EMCrit.org

Airway

(Adapted from the National Emergency Airway Course  http://www.theairwaysite.com and The Airway Cam Guide to Intubation)

RSI evidence review (Can J Anesth 2007;54(9):748)

 

AirwayCam Videos

Levitan Pocket Guide

Universal Algorithms

 

Three Emergent Indications for Intubation

Can't Protect Airway

(Gag reflex is absent in up to 37% of population, so a poor predictor of airway protection (J Accid Emerg Med 16(6):444, 1999)

Lancet. 1995 Feb 25;345(8948):487-8,Clin Otolaryngol. 1993 Aug;18(4):303-7)

Can't Maintain Ventilation/Oxygenation

Expected decline in Clinical Status

Other Reasons include: 

Assess for Potential Difficult Airway

The difficult airway is something you can predict, the failed airway is something that happens to you.  Perform the difficult airway assessment on any patient who has any chance of needing intubation during their stay in the ED.

 

 

 

 

 

Difficult to Bag

·        Beard

·        Obesity                           

·        No Teeth

·        Elderly (>55)

·        Snores

Results: During a 24-month period, 22,660 attempts at MV were recorded. 313 cases (1.4%) of grade 3 MV, 37 cases (0.16%) of grade 4 MV, and 84 cases (0.37%) of grade 3 or 4 MV and difficult intubation were observed. Body mass index of 30 kg/m2 or greater, a beard, Mallampati classification III or IV, age of 57 yr or older, severely limited jaw protrusion, and snoring were identified as independent predictors for grade 3 MV. Snoring and thyromental distance of less than 6 cm were independent predictors for grade 4 MV. Limited or severely limited mandibular protrusion, abnormal neck anatomy, sleep apnea, snoring, and body mass index of 30 kg/m2 or greater were independent predictors of grade 3 or 4 MV and difficult intubation.

Conclusions: The authors observed the incidence of grade 3 MV to be 1.4%, similar to studies with the same definition of difficult MV. Presence of a beard is the only easily modifiable independent risk factor for difficult MV. The mandibular protrusion test may be an essential element of the airway examination. (Anesthesiology 105(5), November 2006, pp 885-891)
 

Difficult to Intubate    (Validated Emerg Med J 2005; 22:99-102)

·        Look at head and neck

·        Evaluate 3-3-2

·        Mallampati (Using Samsoon and Young mod, which added class IV, 1987)

·        Obstruction=hot potato voice, can't handle secretions, and Stridor (if audible=90% obstruction)

·        Neck Mobility

       S for saturation reserve (Ann Emerg Med June 2006)

Difficult Extraglottic Device

·        Evaluate 3-3-2

·        Mallampati

 

Difficult Cricothyrotomy

·        Surgery/Disrupted Airway

·        Hematoma

·        Obese/Access Problems (Can't get to neck)

·        Radiation

·        Tumor

 

MA of difficult airway prediction (Anesthesiology 2005; 103:429–37) best values from combo of mallampati and thyromental distance, but still crappy.

Benumoff's further feelings on extensive evaluation of the difficult airway

Recognition of difficult airway and preoperative evaluation: divided into 11 steps; clinician’s eyes must first focus on teeth, then mouth, oropharyngeal space, mandibular space, and neck; follows line of sight needed when placing laryngoscope blade

Teeth:

1) determine whether maxillary teeth (in involuntary state) lie anterior to mandibular teeth (ie, maxillary teeth “buck” on mandibular teeth); forces laryngoscope blade to enter mouth in more cephalad direction than normal; requires seeing around greater radius of curvature;

2) note length of upper incisors (long upper incisors force laryngoscope blade to enter mouth in more cephalad direction than normal, increasing size of curve);

3) determine whether (in voluntary state) patient can bring mandibular teeth anterior to maxillary teeth (ie, able to prognath); indicates temporomandibular joint not frozen and jaw able to move forward, moving tongue into position to be moved aside during intubation;

4) determine inter-incisor distance (greater than or equal to 3 cm required to get laryngoscope blade into mouth without hitting teeth)
Pharyngeal structures:

5) ability to visualize uvula and tonsillar pillars indicates tongue small relative to size of pharyngeal cavity (therefore relatively easy to move tongue out of line of sight during laryngoscopy; does not necessarily indicate easy intubation); large tongue obscures pharyngeal structures;

6) determine height and narrowness of palate (highly arched and narrow palate can cause intubation difficulty due to smaller oropharyngeal volume)

Mandibular space:

7) determine thyromental distance (ie, distance between inside of mandible and thyroid notch); index of degree vocal cords anterior or posterior relative to other upper airway structures (vocal cords lie directly under midpoint of thyroid cartilage); if thyroid notch very posterior, indicates vocal cords under midpoint lie relatively posterior and relatively straight line from incisors to cords; greater than or equal to 3 fingerbreadths (ie, 6 cm) between inside of mandible and thyroid notch indicates vocal cords posterior, and line of sight relatively straight;

8) determine compliance and distensibility of submandibular space; laryngoscopy retracts tongue into mandibular space; mandibular space made noncompliant by, eg, inflammation, fibrosis, radiation, infection, cancer, edema

Length of neck:

9) qualitative determination; short neck causes intubation difficulty (vocal cords ride relatively high in neck; sharp radius of curvature; lining up angles more difficult); many short-neck syndromes (eg, Klippel-Feil syndrome)

Thickness of neck:

10) qualitative determination; thick neck decreases ability to align upper airway planes

Range of motion:

11) of head and neck; determine whether patient can assume sniffing position (involves 35° flexion of neck on chest; head severely extended (approximately 90°) on neck at atlanto-occipital joint)

Conclusion:

20 to 30 sec required for thorough and complete preoperative evaluation; necessary to have “prepared and educated mind”

 

The 6-D method of airway assessment*
Sign of difficulty Description Quantitative or qualitative findings reported to be associated with difficulty Acceptable findings not usually associated with difficulty
1. Disproportion —Increased size of tongue in relation to pharyngeal size —Mallampati class III or IV —Mallampati class I or II
  —Airway swelling —Possibly difficult to assess  
  —Airway trauma (blunt or penetrating) —Blunt or penetrating airway trauma —Midline trachea
  —Tissue consolidation (e.g., secondary to radiation) —Tracheal deviation —No contractures of the neck
    —Neck asymmetry —No surgical airway scar
2. Distortion —Neck mass —Voice changes —Mobile laryngeal anatomy
  —Neck hematoma —Subcutaneous emphysema (crepitus) —Easily palpated thyroid cartilage
  —Neck abscess —Laryngeal immobility —Easily palpated cricoid cartilage
  —Arthritic changes in the neck joints —Nonpalpable thyroid cartilage  
  —Previous surgical airway —Nonpalpable cricoid cartilage  
3. Decreased thyromental distance —Anterior larynx and decreased mandibular space —Thyromental distance >7 cm (˜3 finger breadths) measured from the superior aspect of the thyroid cartilage to the tip of the chin —Thyromental distance ≥7 cm (-3 finger breadths)
    —Receding chin —No receding chin
4. Decreased interincisor gap —Reduced mouth opening —Distance between upper and lower incisors (i.e., interincisor gap) <4 cm (<2 finger breadths) —Interincisor gap <4 cm (-2 finger breadths)
    —Mandibular condyle fracture  
    —Rigid cervical spine collar  
5. Decreased range of motion in any or all of the joints of the airway (i.e., atlanto-occipital joint, temporomandibular joints, cervical spine); atlantooccipital range of motion is critical for assuming the sniffing position —Limited head extension secondary to arthritis, diabetes, or other diseases —Head extension <35° —Head extension ≥35° of atlanto-occipital extension
  —Previous neck radiation and/or radical surgery —Neck flexion <35° —Cervical spine flexion ≥35°
  —Neck contractures secondary to burns or trauma —Short, thick neck —Long, thin neck
    —Cervical spine collar or cervical spine immobilization —No cervical spine collar or cervical spine immobilization
6. Dental overbite —Large angled teeth disrupting the alignment of the airway axes and possibly decreasing the interincisor gap —Dental overbite —No dental overbite
 

*Based on references 1618, 21. The 6-D method of airway assessment helps practitioners remember to assess for each of the six signs that can be associated with a difficult intubation. Each sign begins with the letter D like the word difficult. The potential for difficult intubation is generally proportional to the number of signs observed. (Baylor Proceedings)


 have patient bite their upper lip (Khan ZH, Gharabaghian M, Ferozeh N, Ghiamat M, Mohammadi M. Easy endotracheal intubation of a patient suffering from both Cushing's and Nelson's Syndromes predicted by the upper lip bite test despite a Mallampati class 4 airway. Anesth Analg 2007;105:786–7)

Miscellaneous Statistics

The incidence of failed airways is 10x greater in term pregnant women, they should always be considered a difficult airway.

Intubation must displace the tongue somewhere, that somewhere is the submandibular space, if that space is occupied by infection/tumor or entirely absent=difficult airway

 

Failed Laryngoscopy (with 3 attempts) :  1 in 200-300 intubations

Can't intubate/can't ventilate (CICV):  1 in 10,000-20,000 intubations
 

PGY 1 or 2: 65% successful on 1st attempt of laryngoscopy
PGY 3/4/Attending 85% successful on 1st attempt  of laryngoscopy

 

We performed as well as anesthesiologists in trauma intubations (Academic Emergency Medicine Volume 11, Number 1 66-70)(Ann Emerg Med. 2004;43:48-53)

 

The Seven Ps of Rapid Sequence Intubation

 

Equipment Preparation

All equipment at the bedside, including backup devices (should be present at every intubation)
Have RSI and post-intubation meds already drawn up. An amp of phenylephrine is also a nice thing to have at the bedside in case the intubating agents cause vasodilatory hypotension.

 

Mnemonic for Equipment during routine intubation (Weingart)

Bag

Airway (oral airway)

Suction (preferably two)

Intubating equipment (tube, blades, etc.)

Capnometer
 

Lubricating the ET tube cuff may lower rates of aspiration (anesthesiology 2001;95:377) 

 

Straight to cuff with 35 degree bend probably is best (ACADEMIC EMERGENCY MEDICINE2006;13:1255–1258)

 

Preoxygenation

Eliminate all the N2 in the FRC
Some BVMs allow active breathing by the patient of 100% O2 while others will give only ~30%. Need duckbill one way valve and an exhalation port.
Do not let the patient take a single room air breath from the beginning of this phase. Kids desaturate much more quickly than adults.  So they are not just little adults, they are little, fat adults
8 vital capacity breaths while wearing a non-rebreather mask is also an alternative.  These masks can be augmented to provide near 100% FiO2 by placing a valve over both vents, providing flow at 15 lpm, and tightly fitting the mask to the face (Resuscitation, April 2003, 57:1, 69 - 72)

When a patient is at <90% saturation, be scared, as this level is right at the nose dive point of the oxygen desaturation curve


Abandon the "hold your breath while intubating" method, it just leads to added stress and underestimates the amount of time you have to intubate

Maximum oxygen in lungs is 87% as 6.5% taken up by CO2 and 6.5% by water vapor.  While the fast track (8 vital capacity breaths) method will cause this 87% concentration, it will not fill the tissue and venous compartments.  Therefore the traditional method will in various studies allow up to 1 1/2 minutes of extra time (Benumoff Lecture)

 

The fast track method

 

NRB only provides 70-75% fiO2 at best

 

Much longer time to desat in the obese if you preoxygenate in sitting position (British Journal of Anaesthesia 2005 95(5):706-709)

 

Patients who can not preoxygenate well with mask should be placed on NIV (Am J Respir Crit Care Med 2006;174:171)

 

Can then use Vent to continue oxygenation until ready to intubate (JEM 2006;30(1):63)

Place on AC: IFR-30 LPM, FiO2-100%, RR-15, Vt-500 cc, PEEP-based on situation

attach a ETCO2 line to set-up

 

Two rcts showed better preox when it is preceded with maximal exhalation(Anesth Analg 2003;97:1533) and (Can J Anesth 2000;47:1144)
functional recovery time of 8.5 min after 1 mg/kg of Sux (Anesthesiology 1997;87:979)

 

Airway press <15 cm H20 rarely causes insufflation
>25 will often cause it (Br J Anaesth 1987;59:315 and Acta Anaesthesiol Scand 1961;5:107)
 

Can J Anaesth. 2007 Jun;54(6):448-52. Click here to read Links
Efficacy of preoxygenation using tidal volume and deep breathing techniques with and without prior maximal exhalation.
Nimmagadda U, Salem MR, Joseph NJ , Miko I.

Department of Anesthesiology, Advocate Illinois Masonic Medical Center, 836 W. Wellington Avenue, Chicago, IL 60657, USA.

PURPOSE: We evaluated the influence of prior maximal exhalation on preoxygenation in 15 adult volunteers using tidal volume breathing (TVB) for five minutes and deep breathing (DB) for two minutes with and without prior maximal exhalation. METHODS: Inspired and end-tidal oxygen, nitrogen and carbon dioxide were monitored continuously and recorded during room air breathing and at 30-sec intervals during 100% oxygen TVB or DB (rate of 8 breaths.min(-1)). RESULTS: Tidal volume breathing with prior maximal exhalation resulted in an end-tidal oxygen concentration (ETO(2)) slightly higher (P = 0.028) at 0.5 and 1.0 min as compared with TVB without prior maximal exhalation at the same time periods. Regardless of whether TVB was preceded by maximal exhalation or not, 2.5 min was required to reach a mean ETO(2) value of 90% or higher. With DB, there were no differences in ETO(2) values at any time period and 1.5 min was required to reach an ETO(2) of 90% or greater, with or without prior maximal exhalation. CONCLUSIONS: Maximal exhalation prior to TVB slightly steepens the initial rise in ETO(2) during the first minute, but confers no real benefit if maximal preoxygenation is the goal. Maximal exhalation prior to DB has no added value in enhancing preoxygenation.

 

comparison of Self-inflating manual resuscitators (SIMRs, i.e. bvms)  for preox  If there is not a one-way exhalation valve, useless for preox(Anesthesiology 2000;93:693)

 

 

P

retreatment

Who needs pretreatment?

·        Tight Brain (Elevated ICP/Head Injury/CVA)

·        Tight Vessels (Aortic Dissection/AAA)

·        Tight Heart (ACS)

·        Tight Lungs (Asthma)

        Reflex responses to intubation

         The larynx one of the most richly innervated areas in the body, this is a primitive airway protection scheme.

·        Bronchospasm can result from laryngoscopy and from intubation. Stimulation of the carina also causes Bronchospasm.

·         Laryngoscopy and intubation also cause increased ICP, both directly and by the catecholamine surge.  Succinylcholine increases ICP by causing more afferent traffic to brain, increasing metabolic activity.

·        Catecholamine surge from adrenal cortex during laryngoscopy and intubation.  Hypercapnia and hypoxia are causes of huge catecholamine surge.

        Non-Pharmacologic Methods to Blunt Reflex Response

·        Limit time of laryngoscopy

·        Atraumatic laryngoscopy

        Pretreatment Meds (LOAD)

         Optimally, give premedications 3-5 minutes before RSI

·        Lidocaine

o       Use in tight brain to attenuate reflex increase in ICP from laryngoscopy/intubation

o       Use in tight lungs to blunt bronchospastic response

o       1.5 mg/kg Rapid IVP

While there is evidence that it blunts ICP rise and cough response, there is no good evidence that this has clinical results (Robinson N. Emerg Med Journal 2001; 18(6):453- 7.) Literature is pretty good on endotracheal suctioning.

·        Opiates

o       Use in tight brain/tight vessels/tight heart to blunt catecholamine surge

o       Fentanyl 3 ug/kg slow IVP

·        Atropine

o       In children less than 10 years old to prevent Sux induced Bradycardia

o       In adults and kids>10 y/o, who receive repeat Sux, for the same reason

o       As an antisalagogue if using Ketamine (can also use glycopyrolate 0.2 mg)

o       0.02 mg/kg

·        Defasiculating Dose of Paralytic

  • In tight brain for adults and kids >5 y/o, when using Sux.  Dog experiments show that sux actually increases ICP not by the fasiculations, but by increased afferent input to muscle spindle fibers; vec or roc can cause a partial spinal blockade attenuating this response (Anes 1986; 64:551)
  • Vec .01 mg/kg or Roc .05 mg/kg (Ron Walls ACEP 2003)
  • Lidocaine and Magnesium prevent the fasiculations as well (MA of RCTs Anesthesiology 2005;103(4):877)
  • Succinylcholine mini-dose can also be used (Ann Emerg Med 1992;21(8):929/47.

Can J Anaesth. 1998 Jun;45(6):521-5. Rocuronium is the best non-depolarizing relaxant to prevent succinylcholine fasciculations and myalgia.
double blind randomized study, 120 female patients CONCLUSION: Among the pretreatments tested, 0.06 mg.kg-1 rocuronium was the best to prevent muscular fasciculations following succinylcholine injection. In the population studied, pretreatment did not prevent postoperative myalgia. Succinylcholine 1.5 mg.kg-1 was more effective without a non-depolarizing pretreatment.

 

A randomized, double-blind comparison of rocuronium, d-tubocurarine, and "mini-dose" succinylcholine for preventing succinylcholine-induced muscle fasciculations. (Anesth Analg. 1998 Sep;87(3):719-22.)

 

Intralingual succinylcholine injection provides a rapid onset of muscle relaxation in an emergency.
Anaesthesia. 2001 Dec;56(12):1213.

 

Reglan

in GI bleeds/full stomachs

 

 

P

aralysis after Induction

·        Brutane (forcing non-paralyzed musculature) is the worst choice of medications

      Do not give sedatives without paralytics, as there is a good 6 minutes of IPIST (Interval of Progressively Increasing Sphincter Tone) between administration and full sedation

Induction/Sedative Agents

·        Etomidate or Versed .3 mg/kg

·        Ketamine or Propofol 1.5 mg/kg

·        Pentothal 3 mg/kg

 

     Etomidate mycoclonus can be attenuated c small dose benzo

 

     Use ½ dose of induction agents if vital signs are unstable or the patient is elderly. Consider using a dose of zero if the sympatholysis may result in decreased BP

     In a analysis of NEAR data, thiopental, methohexital, and propofol appeared to facilitate RSI over etomidate and versed.  The                    postulated reason for this is that these agents allow a deeper plane of sedation making up for inadequate waiting time for paralysis.  (Acad EM 10:6, 2003)

 

Dose based on ideal body weight; estimate by Broca index: (height in cm-100 for men, -105 for women)

 

ketamine for head injury review (emerg med australia 2006;18(1):37-44) (also see sedative section)

editorial on the use of ketamine in intubation ( Chest. 2007 Dec;132(6):2054)

Paralytics

Paralytics usually spare pupils (Shah.  Emergency Neurology, p.5)

Depolarizing

Succinylcholine is the only one used in the US.

Sux dosing 1.5-2 mg/kg, always better to give more than less.

Action in 45 seconds, clinical duration 6-8 minutes

Typically causes a rise of 0.5 mEq/L of potassium

Dose based on actual not ideal body weight, gives better conditions in the fattys (Anesth Analg 2006;102(2):438)

 

When not to use Succinylcholine:

·        Any strokes with hemiparesis from 3 days to 6 months

·        Burns/trauma >24 hours old

·        NMJ Disease

·        Myopathies/Muscular Dystrophies

Theoretical Concerns

·        Intraocular pressure:  commonly used by anesthesiologists in this situation.  (Anesth Clin North Am 1996 14:125-150 and Anesthesiology 1985; 62: 637-640)

·        Preexisting Hyperkalemia (Renal failure is not a contraindication): In a retrospective study of all patients  with hyperkalemia (38 of 40,000) receiving sux, there were not adverse events (Anesth Analg 2002 Jul;95(1))

·        Known plasma cholinesterase deficiency: (only risk is prolonged duration of action)

Burns:  no real risk as long as less than 7 days from the burn or several months after (after healing, return of normal appetite, and return to normal weight)

Direct Muscle Damage:  no risk until 4-5 days after insult

Guillain-Barre:  do not use during and for months afterward

ICU:  If chronic muscle atrophy, may be better not to use for up to a year afterwards

Myopathies:  Contraindicated forever if inherited

(From correspondence from G. Gronert, MD)

Multiple Sclerosis: Review of Sux & neuromuscular disorders (Anesth 1984;61:173)

Not a great idea in patients with MS induced paresis (Curr Opin Anaes 2002;15:365)

Case Series of Numerous MS Patients who received Sux (Ann Chir Gynaecol. 1984;73(5):299-303)

1 case report in the literature of hyperkalemia in MS (JAMA 1970;213:1867)

 

Sux remains 90% effective at room temperature for 3 months, longer if not exposed to light (Rosen’s 2001)

Lasts for months at room temp (Emergency Medicine Journal 2007;24:168-169)

 

Sux can be injected intralingually if unable to obtain IV access (Intralingual/Intraoral in Adult Anaesthesia 56:12, 1213 Dec 2001)

 

Submental/Intralingual use of Nalaxone--23-gauge, 1.5-inch needle attached to a 3-mL syringe was inserted in the midline, midway between the mandible and the thyroid cartilage. It was directed 1 inch superior, and 2 mL of naloxone solution was injected. The SM area was then massaged for 30 seconds

Intralingual naloxone injection for narcotic-induced respiratory depression. Ann Emerg Med 1987;16:572-573.
Mercurio JP: Emergency submental injection. JADA 1967;74:717-719.

Redden RJ, Miller M, Campbell RL: Submental administration of succinylcholine in children. Anesth Prog 1984;12:1087-1091.

 

The experience of paralysis when awake is not so bad, but hypercarbia seems to suck (J Clin Anesth. 1993 Sep-Oct;5(5):369-74.)

 

If you wait 60 seconds, then induction agent is irrelevant (British Journal of Anaesthesia 2005 95(5):710-714)

 

A  second dose of suxamethonium in the presence of masseter spasm. This should not have occurred for two reasons:

  1. Masseter spasm is an early sign of malignant hyperpyrexia (MH), which has a mortality rate even with dantrolene of around 5%. Suxamethonium is a significant precipitant in susceptible individuals.
     
  2. Repeated doses of suxamethonium change the paralysing effect of the drug from one that wears off within 3–5 minutes ("Phase I block") to one resembling a non-depolarising neuromuscular block ("Phase II block") which lasts significantly longer. It has been long established that this type of block may begin at doses of 2 mg/kg.2

IM Sux-need 4mg/kg to get 2-3 minute induction time (Anaesthesia 2007;62:757)

 

Sux and Hyperkalemia

Anesthesiology 2006; 104:158–69 (massive review down to receptor level)

Ped Emerg Care 2000;16(6):441--can not blunt hyperkalemia with non-depols

Chest 1992;102(4):1259--can not blunt hyperkalemia with non-depols

Seminars in Anesthesiology 1985;4:65--same

Anesth 1975;43:89--article references by Anesth 2006

JAMA 1969;210:490

Anesthesiology. 1973 Jul;39(1):13-22.--The response of denervated skeletal muscle to succinylcholine, using canine muscles both normal and denervated



25. R.E. Tobey, P.M. Jacobsen, C.T. Kahle, R.J. Clubb and M.A. Dean, The serum potassium response to muscle relaxants in neural injury. Anesthesiology 37 (1972), pp. 332–337. View Record in Scopus | Cited By in Scopus (8)

26. A.A. Birch, G.D. Mitchell, G.A. Playford and C.A. Lang, Changes in serum potassium response to succinylcholine following trauma. JAMA 210 (1969), pp. 490–493. View Record in Scopus | Cited By in Scopus (10)

 

27. G.A. Gronert, Potassium response to succinylcholine. JAMA 211 (1970), p. 300.

 

Anaesth Intensive Care. 1990 Feb;18(1):92-101.Links
Suxamethonium and hyperkalaemia.
review including 0.7-1.2 rise in renal pts

 

 

Nondepolarizing

Sugammadex

is being tested; it binds to roc and completely reverses its effects

                    Phase II Study: Anesthesiology 2007;106:935-43

 

  Ephedrine 70 ug/kg Placebo Esmolol 0.5 mg/kg
CO 9.1 8 5.5
Onset of Roc 0.6 mg/kg in sec 52 87 114

(Acta Anaesthesiol Scand. 2003 Oct;47(9):1067-72.)

 

Aspiration is less likely with NMBA

1 mg/kg of Sux will give excellent intubating conditions 63-80% of time

Time until diaphragmatic movement were the same between 1 mg/kg and 0.5 mg/kg dose (Donati, François - Muscule Relaxation for Rapid Sequence Induction IARS 2006 Review Course Lectures)

 

Prefasic dose of Rocuronium is 0.03 mg/kg 3-5 min before intubation

You must increase dose of sux to 2mg/kg  if prefasic dose of non-depol is given

 

Corrugator Supercillii, which moves the eyebrow in response to facial nerve stim has response to NMBAs similar to vocal cords and diaphragm.

 

 

Article on intubating without paralysis (Br J Anaesth 2005;94(2):150)

lidocaine sprayed on cords

remifentanyl 2 mcg/kg


 

ROCURONIUM VERSUS SUCCINYLCHOLINE FOR RAPID SEQUENCE INDUCTION INTUBATION
Background
Rapid sequence induction (RSI) of anaesthesia is a method of quickly producing optimal conditions for intubation in the emergency situation. Classically, succinylcholine (also known as suxamethonium) is the muscle relaxant used because of its rapid onset and brief duration. Contraindications for its use include severe burns, major crush injuries, neurological disease involving acute wasting of major muscle and family history of malignant hyperthermia. Rocuronium is another rapid onset muscle relaxant with fewer contraindications than succinylcholine but its duration is significantly longer. The aim of this meta-analysis was to assess whether rocuronium is as effective as succinylcholine at producing ideal intubating conditions during RSI.


Results
Twenty six studies were identified that met the inclusion criteria. Succinylcholine produced a small but statistically significant increase in the number of excellent versus non-excellent intubation conditions (relative risk (RR) 0.87; 95% CI 0.81 to 0.94). There was no significant difference between the two agents when comparing excellent or good intubating conditions with poor conditions or failure to intubate. When propofol was used in place of thiopental, there was no difference in the numbers of excellent conditions produced by either rocuronium or succinlycholine.


SOCRATES says
Succinylcholine produces excellent intubation conditions more consistently than rocuronium and remains the first choice muscle relaxant for RSI. In cases where it is contraindicated, rocuronium is a valid alternative, especially if combined with propofol.

Perry J, Lee J, Wells G. Rocuronium versus succinylcholine for rapid sequence induction intubation. In: The Cochrane Database of Systematic Reviews. 2005 Issue 4 CD 002788



 

 

 

 

Train of Four

Number of Twitches After Stimulation

Amplitude

Corresponding Level of Neuromuscular Blockade

4

all 4 equal

0% (no blockade)

4

declining

< 75%

3

declining

75-85%

2

declining

85-90%

1

single weak

91-99%

0

none

100%

4:1 50% same 70% occupied
2-3 twitches same 75-85% occupied
1 twitch weak >90%
Post tetanic twitching >5 occurs just beofre rgaining 1 twitch of TOF    

 

To Reverse, Need 1 twitch

Neostigmine 0.07 mg/kg, mix in same syringe with equal volume of glycopyrolate

 

Sedation without Paralysis

Complications of emergency intubation with and without paralysis. (Am J Emerg Med. 1999 Mar;17(2):141-3)
 

 

P

rotection and Positioning

Cricoid Pressure (Sellick's)

from 20-30 seconds after drugs until tube confirmation.  Have assistant apply with third finger and thumb.  Place their index finger on the thyroid cartilage, this will allow you to move it during laryngoscopy to retain BURP pressure. The proper amount of cricoid pressure can be learned by pushing on the bridge of your nose with middle finger and thumb until it hurts.

 

But perhaps, the proper amount is no amount at all. All studies are inconclusive. (Canad J Anesthesia 1997;44:414 in JB) and it often screws up tube placement (Airway·Cam Book)

 

            Position the patient

·        Leave patient sitting until last moment in CHF/Reactive Airway Disease

·        Do not bag unless sat starts to fall below 90.  If you bag with paralysis and properly performed cricoid pressure, 1-2 cc of air is       insufflated per tidal volume ventilation.

·        Also consider bagging patients with increased ICP.

·        Never bag without an oral airway, just as you would not perform a rectal exam without a glove

 

 

P

lacement and Confirmation

Wait till defasiculations cease if using Succinylcholine; flick the mandible to see if pt sufficiently blocked and

 

Intubate

  • see below

       Confirm Placement

·        ETCO2 Detector-yellow is mellow.  If tan, give 6 breaths.  If still tan probably in trachea, but consider direct laryngoscopy to confirm.  Purple with a Pulse, Pull the tube.  If purple without a pulse, confirm with direct laryngoscopy.
If using wave-form CO2, then tracheal intubation should produce waveform.
Vinegar in an animal model turned permanently turned indicator yellow (Journal of Emergency Medicine
Volume 28, Issue 1 , January 2005, Pages 5-11)

 

The colour ranges for the Portex® device (Smiths Medical ASD, Keene, NH) are blue, green, green-yellow, and yellow, which correspond to levels of 0–1, 1–2, 2–5, and >5% CO2, respectively. Normally, end-tidal CO2 is > 4%.1,2
Go to source: CAEP - Canadian Association of Emergency Physicians | ACMU - Association canadienne des médecins d'urgence: - EDUCATION • ÉDUCATION

 

 

 

 

·        Primary assessment (Lung sounds) more for tube depth than confirming tracheal placement.

If confirming in a coded patient, first attempt to verify with DL-Displace tube posteriorly to be able to see it going through the cords (Benumoff 2nd ed)

 

Also can place a boughie down tube, if you hit a stop point, it is in the bronchi and tube is between the cords

 

Tube Cuff Pressure

We probably inflate too much (Academic Emergency Medicine Volume 11, Number 5 490-491)

Emergency Physicians Cannot Inflate or Estimate Endotracheal Tube Cuff Pressure Using Standard Techniques (Annals EM 44:4 Oct 2004) and (AJEM 2006;24:139)

15-25 mmHg is optimal

 

Pulse Ox

Distally placed pulse ox has a 60-90 second lag from true saturation
 

 

 

Postintubation Management

Valium .2 mg/kg

Ativan 4-6 mg

Versed 0.1 mg/kg bolus, then 0.1 mg/kg/hr 2-5 mg/hr  (Drip 50 mg in 250 cc NS, Start at 10-25 cc/hr)

Propofol .5-1 mg/kg then 25-100 mcg/kg/min, start at 10 cc (100 mg)/hr which correlates with 1 mg/kg/hour

 

Vecuronium .1 mg/kg then .03 mg/kg  q25-45 min or 1-2 mcg/kg/min

use 2 electrodes over the ulna nerve, give train of four.  shoot for 2 twitches while holding the thumb in abduction

Acute quadriparetic myopathy syndrome (AQMS) can result in longstanding paresis if NMBAs are given in doses which are too high.

HOB 30°

Big Tubes

Secure ‘em

NGT

HME

ABG

Inline Suction

ETCO2

BVM c peep valve

Cuff Pressure

Abnormal Vital Signs Postintubation

Bradycardia

Assume hypoxia and therefore tube displacement until proven otherwise

Desaturation

Displaced tube

Obstruction-pass suction catheter through tube

Pneumothorax

Equipment failure-take off vent and bag patient

 

if all of the above have been evaluated, consider shunt physiology

Hypotension

·        Pneumothorax

·        Decreased Venous Return from PPV, disconnect from vent for 30-60 seconds and observe for increased BP and decreased pulse.  Consider reducing PEEP and decreasing Vt.  Auto-PEEP in obstructive airway disease.

·        Induction Agents-diagnosis of exclusion, give fluid bolus

·        Cardiogenic-fluid bolus

Skills of Airway Management

Using a BVM

Always use an oral airway

·        Take mask off of bag

·        Lay over nose and let fall on the face

·        Place thumb and first finger on mask with port against thumb web

·        Attach the bag

·        Use the other fingers to grasp along mandible, pulling face into mask

2 hand method:  place  both thumbs on mask, facing the patient’s feet.   Index fingers on mentum of chin.  Other fingers performing jaw thrust.

 

Use 2 nasal and oral airway if difficult to ventilate.

• comparison of 4 standard bags with
high-flow oxygen
• Duck-bill mask with one-way valve gives
FiO2 >0.9, other bags ~0.3
• Laerdal Silicone Resuscitator®,
Mallinckrodt Capno-Flo® > 0.9
• Sims-Intertech 1st Response®, Vital Signs
Code Blue® < 0.4
• Know your bag well: they’re different
Nimmagadda, et al: Anesthesia and Analgesia 93:693-8,2000.
(Ron Wall's Lecture)

 

Esophageal sphincter is 20-25 cm H2O in normal healthy, less in sick or dead

 

Better technique may be to use mask and ventilator (Journal of Emergency Medicine 2006;30(1):63)

 

Nasopharyngeal Airways

Short Female Size 6 (pin 1cm from flange)

Average Female/Short Male Size 6

Tall Female/AVerage Male Size 7

Tall Male Size 8

 

width does not matter, only length so that it is above cricoid but below tongue

(Emerg Med J 2005;22:394-396)

 

 

 

NRB = ~65%
Ø BVM = 90%
• New Hi-Ox® Mask >80% @ 8L/min

 

New smart bag limits IFR (Intensive Care Medicine Volume 34, Number 2 / February, 2008)

 

Laryngoscopy and Intubation

The tongue is your enemy, the epiglottis is your friend.

 

When passing the tube, first touch the hard palette with the tube’s bevel lying horizontally.  Guide the tube to the soft palette.  Approach the cords from the right so as not to obscure your view.  At the last second, rotate the tube counterclockwise 90° to allow narrowest area to go through the cords.

 

Macintosh must indirectly lift the epiglottis by use of the hyoepiglottic ligament.  If the macintosh blade is too short for the patient, you may be able to reach the valeculla, but have inadequate traction to lift the epiglottis.

 

Teach residents by telling them to life the head off of the bed with the blade rather than tilting the head back with the blade

 

Six Steps

  1. Position the patient

  2. Open the mouth: this is key, if the condyles of the mandible do not translate on to the zygoma, the jaw can not be pushed forward

  3. Control the Tongue

  4. Control the Epiglottis

  5. Landmark Recognition

  6. Pass the tube

 

Increased head elevation/neck flexion results in much better view (Annals EM 2003;41(3):322)

Mike Murphy agrees with editorial in same issue (Ann Emerg Med 2003;41(3):338)

                            

Ideal positioning causes the external auditory meatus to be on the same horizontal line as the sternal notch. If this is accomplished using the ramp method in this photo, obesity will not cause difficulty (Obesity Surgery 2004;14:1171)

 

Another review article showing same in pregnant, obese woman  (Can J Anaesth 1989;36(6):668)

 

RCT with crossover of extension vs. 7cm head elevation, trend towards better with ramp, sig. btter in obese or poor head extenders (Anesth 2001;95:836)

 

Laryngoscopy with straight blade allowed better view, but intubating conditions were better with the curved blade. (Can J Anesth 2003, 50:5 p. 501-506)

 

For difficult laryngoscopy, can try the left-molar approach.  It may offer an improved laryngeal view.  It can also be used to augment fiberoptic intubation attempts.  (Anes 92:1, Jan 2000) and (Anaes 2002 57:1028-1044)


Consider having assistant grab the tongue with a 4x4 before the insertion of the blade.

 

BURP and mandibular advancement gave the best visualized view. Either one alone helped over none in inexperienced laryngoscopists (Anesthesiology 2004; 100:598–601)

 

Comparision of cricoid/burp/bimanual laryng. (Ann EMerg Med 2006;47(6):548): on cadaver models, only bimanual consistently improved view

 

 

 

Cormack-Lehane is scale for view of cords

 

Plastic Blades result in lower number of successful intubations (Anesthesiology 2006;104(1):60)

 

Pediatric Airway

High larynx is more accurate than anterior larynx.  Kids airways are very consistent, but you need to know where to look.

Kiddies are very difficult to preoxygenate
Use straight blade in infants/small children

No defasiculating meds in children <10, be very wary of using opoids in kids (they are usually sympathetically dependant when ill) Pretreatment mnemonic is LAD (lidocaine, atropine, ± defasiculating dose) for lads instead of LOAD
 
Collar all peds when tubed, minor changes in neck position can cause extubation.

Use commercial tube holders preferentially.

Upper Airway Obstruction

Should still be able to bag

 

Nobody actually gets to do needle crics on kids, even the people who author articles may never have done it on a real kid.  Use 14 g angiocath or better yet, non-bendable 12 g specifically made for this purpose.  Put the needle anywhere (Pretend you are cannulating a vein) and use #3 ET connector.  It will be very difficult to bag, this is normal. Or use 2.5 et adapter with infusion tubing. (AJEM Jan 2004)

 

Partial obstruction=wait for back up

Full Obstruction=

Back blows/chest thrusts

Look c McGill's

Push down mainstem with ET tube

Pediatric Airway Equipment

Dangerous Equipment

The Difficult Airway

Blind Nasotracheal Intubation

Consider awake BNTI in a predicted difficult airway

 

start with 32 french trumpet anesthetize through it to get post pharynx

 

Use the left nostril or if using the right turn tube 180° 

Facilitated by neutral head position and ET tube cuff inflation to 15cc.  This study used trachlite without guidewire (Can J Anesth 50(5):511, May 2003)

 

depth is 26-28 cm at nares

 

aim towards contralateral nipple

 

If BVM and intubation are predicted to be successful, do double set-up RSI with failed airway equipment already set up and cric set open

 

Quick Look

Give intubating dose of propofol, perform laryngoscopy, give paralytics if a good view is obtained

Awake Intubation

Topicalization (Choose 1 of the 4)

·        5 cc 2% lidocaine and 5cc 2% Lidocaine with 1:100,000 Epi nebulized

·        Lidocaine 4% 5cc nebulized

·        4cc of 4% Lidocaine and 1 cc of 0.5-1% Neosynephrine nebulized (alternative 3 cc of 4% and 3 cc of NS)

·        Lidocaine/Hurricaine spray (if no time for nebs) or use mucosal atomization device to spray 4% Lidocaine in oropharynx

Anesthetize Lower Airways

·        Translaryngeal injection of 2-4 cc 4% lidocaine

Nasal Vasoconstriction/Anesthesia

·        Soak pledgets in 4% lidocaine and leave in nose for 5 minutes and/or spray c 2% neo-synephrine. Or use 4% cocaine (max 1-3 mg/kg) or Lidocaine with 1:25,000 epinephrine

Antisalagogue (Choose 1)

·        Glycopyrolate 0.2 mg IV

·        Atropine .01 mg/kg IV

Sedate (Choose 1)

·        Versed 2-4 mg (takes 3-5 minutes for effect)

·        50% Ketamine and 50% Propofol in a syringe (5 cc of each)  Give in small aliquots. Ketamine alone, give 1/5 dose intubating dose, wait and repeat if necessary (Volume 92(6) June 2001 pp 1465-1469 The Effects of Small-Dose Ketamine on Propofol Sedation: Respiration, Postoperative Mood, Perception, Cognition, and Pain)


Placing the tube is even more physiologically invasive than laryngoscopy.  Consider taking quick look and if the cords are easily visualized in a non-dynamic situation, consider RSI at that point, otherwise just pass the tube.

 

2% viscous for swishing through mouth, coat nasal trumpet

5% ointment place on back of tongue and oropharynx with tongue blade

 

Pacey's pastemake slurry by combining 2% viscous with 4% using 3 way stopcock to mix

can add sweet & low to make more palatable

Crash Airway

Nearly Dead, Newly Dead

Still may consider using Sux if any muscle tone at all

Failed Airway


Can't Intubate/Can't Ventilate or three failed attempts

Best Attempt Definition:

  1. Performed by a reasonably experienced laryngoscopist

  2. No significant muscle tone

  3. Use of optimal sniff position

  4. Use of external laryngeal manipulation

  5. One change in length of blade

  6. One change in type of blade

 

Devices and Techniques in the Failed/Difficult Airway

Eschmann/Gum Rubber Bougie

Pass till 20 cm at the teeth, you will feel it sliding over tracheal rings.  Railroad the tube over the Eschmann while the laryngoscope is still in the mouth.

 

The laryngoscopist obtains the optimal laryngeal view. The bougie is then passed below the epiglottis and through the vocal cords. This should elicit a clicking feel at the distal end of the GEB due to the "hockey stick" angled distal end [5]. If clicking is not felt distinctly, the GEB is advanced further until it "holds up" at the carina or when it comes in contact with a peripheral airway of a smaller diameter [5]. Advancement always must be gentle. The laryngoscope blade is left in place as the ETT is inserted over the GEB and into the trachea. It is important to rotate the ETT 90 degrees counterclockwise before the tip of the ETT passes through the vocal cords. This maneuver prevents the beveled tip of the ETT from catching on the right arytenoid process, aryepiglottic fold, right vocal cord, or epiglottis. Clicking and holding up are cardinal signs of tracheal insertion by the GEB, both of which were noted during the insertion of the GEB in our patient with the open zone II neck injury.

Possible complications from a bougie insertion are pharyngeal perforation, mediastinal emphysema, and pneumothorax. (JEM April 2003)

 

The obstruction is caused by impingement of the tube on the right vocal cord complex and arytenoids [2]. Cossham [3] described a pre-emptive 90° anti-clockwise rotation of the tube (90CCWR), the Cossham twist

 

: Am J Emerg Med. 2004 Oct;22(6):479-82. Links
Use of the endotracheal bougie introducer for difficult intubations.
Phelan MP
Department of Emergency Medicine/E19, The Cleveland Clinic Foundatin, OH 44195, USA. phelanm@ccf.org
A difficult to intubate patient occurs infrequently in the emergency department. The endotracheal tube introducer or gum elastic bougie is a device used by British anesthesiologists in difficult airways. The device is inexpensive, has few complications and is easy to use. Similar to the Seldinger technique for gaining access to a large central vein, the endotracheal tube introducer is used to assist in cannulating the trachea and acts like the wire in central vein access.
PMID: 15520943 [PubMed - indexed for MEDLINE]
 

Combitube

Hold right above yellow balloon

Use thumb to press tongue out of way

 

Place until teeth between two black lines

Inflate blue cuff until lower black line moves above the teeth (relative amount)

Inflate white for 12 cc (absolute amount)

Blue is first for everything (inflation, deflation, ventilation)

Combitube Video

 

Trach Light

·        Cut Tube to 27 cm and reattach connector.  Lube wire and lube stylet

·        Bulb should be flush with distal part of bevel, it should just touch your finger.

·        Hold like a cup of tea (between thumb and index finger, pinky up is your choice)

·        In Peds, only pull back 2-3 cm on wire

·        Must bend 90 or it will not work

·        Touch it to the patient’s chest in midline and then rotate it in while performing a jaw thrust.

·        Patient’s head can be in neutral position

Pictures of Insertion at the Airway Site

Several tips have been suggested in the literature for improving the success of Trachlight®-guided intubation. These include lifting the tongue with the thumb of the nondominant hand or having an assistant pull the tongue while the intubator continues to provide a jaw thrust, lubricating the wand and the stylet,1 dimming operating room lights, using smaller size endotracheal tubes, inserting the wand side-on, or providing at least a 90° bend to the wand.2 Others have suggested gauging the appropriate "bent length" by measuring the distance from the thyroid prominence to the angle of the mandible.3 Patients with buck teeth may benefit from the addition of another bend to the wand at the level of the buck teeth.4

Following repeated use, the internal rigid stylet sometimes assumes a "snake-like" bend that poses difficulty in retraction of the wand. In such situations, it has been suggested that the stylet be straightened, if possible, before reuse, failing which it needs to be disposed. 5 We have also encountered a similar situation leading to difficulty in withdrawing the wand along with the rigid internal stylet after successfully negotiating the endotracheal tube-Trachlight® assembly into the trachea. We have noticed that the snake-like bend of the stylet poses a problem when it crosses the endotracheal tube connector, which happens to be not only the narrowest, but also the most rigid portion of the endotracheal tube-connector assembly. We have successfully overcome "hold up" at this level by separating the endotracheal tube connector from the endotracheal tube prior to withdrawal of the wand-stylet assembly. The distal 90° bent portion of the wand-stylet assembly is the other point at which difficulty is encountered during withdrawal of the stylet, especially in the pediatric age group due to the small size of the tube and its connector. Our suggestion provides a solution to this problem also. We therefore recommend that the connector be routinely separated from the endotracheal tube to facilitate smooth removal of the stylet and possibly prolong the life of the stylet. We have applied this technique of removal of the endotracheal tube connector to aid in Trachlight®-guided oral intubation using the Ring Adair Elwyn (Mallinckrodt Medical, Athlone, Ireland) tube also.

In obese individuals, the midline tissues of the neck may be obscured by folds of fat arising either from a double-chin above, or from the anterior chest wall below, posing difficulty in appreciation of the circumscribed glow in front of the neck. Dimming the operating room lights and placing a support under the shoulder to extend the neck often improves success of Trachlight®-guided intubation in obese patients. We have found that having an assistant retract the fold of fatty tissue down and away from the neck so as to avoid formation of skin folds over the neck helps in shortening the time to obtain the classical well-circumscribed midline glow.

Since its introduction in 1959, the lightwand has proven its utility in several clinical situations. Our experience gleaned from the use of the Trachlight® for more than 350 intubations has prompted us to share some of the practical solutions that we have used to overcome problems that we have commonly encountered during its use. (Can J Anesth 2007;54:398-399)
 

Glidescope

More maneuvers to facilitate tracheal intubation with the GlideScope®
David C. Kramer, MD and Irene P. Osborn, MD
Mount Sinai Medical Center, New York, USA, E-mail: david.kramer@msnyuhealth.org


To the Editor:

The GlideScope® (Diagnostic Ultrasound Corporation,Bothell, WA, USA), is a videolaryngoscope, whichincorporates a fibreoptic and digital camera systeminto the blade.1 The blade displays a video output to adedicated monitor. The flange of the blade has a 60°angulation, which facilitates better exposure of the larynxthan traditional Macintosh blades.2,3 Some authorshave reported difficulty intubating the trachea despitethe superior view offered by the GlideScope®.1 In thelargest series of Glidescope use (728 patients), 14 ofthe 26 failed intubations occurred in spite of achievinga Cormack-Lehane grade 1 view.4 In that study,failures resulted not from an inability to view the larynx,but in directing the endotracheal tube throughthe glottic opening. In our experience, the device hasbeen successful in over 500 patients, especially thosewith large tongues, relatively small mouths, and inpatients with limited neck mobility. We have used thedevice for conventional induction, in rapid sequenceintubation, and for awake intubation. Because theGlideScope lifts the tongue rather than displacing itinto the submental space, patients with Mallampaticlass III and IV airways are usually afforded Cormack-Lehane grades 1 or 2 glottic views.

We have found the following maneuvers to be helpfulwhen intubating the trachea with the GlideScope®:


Using a stylette, bend the endotrachealtube (ETT) into a "hockey stick" shape; thisusually facilitates tracheal intubation if oneobtains a Cormack-Lehane grade 1 view. Ifthe larynx appears anteriorly, bending the ETTinto a steeper curve is helpful. This can beachieved by emulating the bend of theGlideScope® flange and handle.

Introduce the ETT through the mouth in ahorizontal plane, and once the tube has passedthe flange of the GlideScope®, rotate the ETTto the vertical position.

If the ETT advances posteriorly to the arytenoids, the following is helpful: With the ETTheld between the fingertips, pull it superiorly,rotate the ETT over the left arytenoid, and gently twist the tube over the epiglottic aperture.

If the ETT abuts the glottic lip, rotate the ETTclockwise into the glottic aperture, while with-drawing the stylet.5

A midline approach and positioning to achievean optimal laryngeal view is also important. The described maneuvers have helped the authors facilitateintroduction of the ETT into the mouth, past theGlideScope®, and decrease the risk of trauma to theposterior larynx and tracheal glottis. These approacheshave also been very helpful in teaching proper useof the GlideScope®, and in managing failed trachealintubations at our institution.
 

LMAs

 

CLINICAL SKILLS FOR THE PREHOSPITAL USE OF THE LMA
Similar to the first laryngoscopy,41 the first LMA insertion attempt should be optimized.

Is the Correct LMA Size Selected?
The LMA Classic is available in six sizes. The manufacturer recommends two size selection criteria: weight based (for adults patients: size 3, 30 to 50 kg, size 4, 50–70 kg, size 5, 70–100 kg, and recently size 6 for >100 kg) and gender based (size 4 for female and size 5 for male adults). The manual also recommends that clinical judgment should be used in selecting the size.

Is the LMA Ready to Use?
The device is prepared (deflation and lubrication of the dorsal surface with a water soluble lubricant), stored, and used in an uncontrollable and unpredictable environment. The LMA, water soluble lubricant and a syringe should be packaged together. The disposable LMA-Unique (sizes #3, #4, and #5) (LMA North America, San Diego, Calif.) offers this advantage.

Is the Patient Ready to Accept the LMA?
Insertion of the LMA during inadequate level of anesthesia is a common mistake. A patient who is not “deep enough” (gagging, coughing …) will fight the LMA insertion and discourage the rescuer from inserting the index finger deep into the mouth resulting in misplacement of the device. A misplaced LMA is more likely to be dislodged or to trigger reflexes (laryngospasm, glottic closure, vomiting, or hiccups).42

In the OR the loss of motor response to the “jaw thrust” is considered more reliable to assess adequate “depth” than the loss of verbal contact with the patient.43 Unwanted effects of the jaw thrust may include cervical spine mobilization and stimulation of the patient.

Optimal Insertion of the LMA
The rescuer will insert the LMA in variable positions: standing (emergency room), kneeling (scene, ambulance), sitting (helicopter), and from the patient’s side (difficult extrication). Experienced anesthesiologists need at least 2 cm distance between the upper and the lower incisors to insert the LMA.44 The kneeling position is suboptimal for the ETT placement but advantageous for the LMA insertion. The standard index finger technique is used when standing or kneeling at the patient’s head. This technique is superior to any other insertion techniques.45 The thumb technique is useful when the victim is trapped (motor vehicle crash) or difficult to reach from above the head. The rescuer standing by the side of the patient will use the thumb of the dominant hand that substitutes the index finger to guide the LMA along the palato-pharyngeal path. The insertion success rate of the thumb technique is lower than the index finger technique.46

The most common error made during the early learning phase with the standard technique is the insertion of the LMA straight into the mouth without using the hard palate as a slide and with the index finger not inserted deep enough into the mouth, misplacing the LMA. Other reasons for failure are: choice of wrong LMA size, incomplete cuff deflation, inability to get the mask past the teeth, inability to advance the cuff past the base of the tongue, insufficient air, or overinflation of the LMA cuff.47 An automated voice advisory manikin may correct these predictable mistakes.48

Neutral head position, CP, and MILS can complicate the LMA insertion. Insertion of the LMA should be attempted with the anterior half of the cervical collar removed and MILS applied. Brimacombe recommends that LMA insertion with CP applied should be attempted only if the oxygen saturation (SpO2) is >95%. If insertion fails, CP should be released for the second attempt. If the SpO2 is <95% initial insertion should be with CP released as ventilation/oxygenation is more important than preventing aspiration.13

Optimal Cuff Inflation
Inflate the cuff with two-thirds of the maximum volume recommended (marked on the LMA tube), then, add 3 to 5 mL of air, as needed up to the maximum volume recommended. A rigid over inflated cuff will loose its ability to mold on the soft periglottic tissues: over inflation will not compensate for malposition but will further compromise the seal and the use of PPV. The manufacturer recommends the use of a pressure gauge for optimal cuff inflation. All current literature pertinent to supraglottic airway devices (SGD) standardizes cuff inflation pressure to 60 cm H2O.

LMA Ventilation
Pharyngeal and esophageal leaks are expected with airway pressure over 20 cm H2O. Overzealous ventilation with no airway pressure monitoring can lead to a “misperceived” leak in an otherwise correctly placed LMA. Chest movement with small TV may be difficult to evaluate in a dressed victim, with chest trauma or strapped chest. Auscultation (chest, neck, and epigastrum) with small TV in a noisy environment may be deceiving. The use of the inflatable bulb (esophageal detector device) with the LMA is discouraged.49

In the OR the most specific test to detect LMA misplacement (defined fiberoptically) was the ability to generate airway pressure of 20 cm H2O without a leak whereas, the ability to ventilate manually (movement of the chest, condensation of expired gases, adequacy of expired gas volume and the feel of the bag) had the highest overall accuracy.

Is the Patient Ready for Transport?
Tape the LMA firmly in the midline to the upper jaw without bending the tube toward the forehead; keep the LMA tube in a neutral position (bended toward the chin) being vigilant not to dislodge the device during transport or manipulation of the resuscitation bag. A bite block will increase the device’s stability.50 Asai et al. considers that although CP applied after correct placement of the LMA significantly decreases the incidence of gastric insufflation, it also decreases the adequacy of ventilation.51

Ventilation should be reassessed after the application of the anterior cervical collar. If monitored, the airway pressure should be kept under 20 cm H2O.

Regurgitation in the LMA Tube
Brain considers the LMA cuff protective by filling the pharyngeal space otherwise filled with aspirate and should not be removed; also the LMA tube represents a path of minimal resistance, an alternative to the trachea.52

In the event of regurgitation/aspiration disconnect the breathing tube and allow regurgitated material to drain, and then gently ventilate using small tidal volumes (TV) with 100% Fio2. Place the patient with cervical spine precautions in Trendelenburg position. Sedate and/or paralyze the patient that is “too light.” Oxygenation should be maintained during the incident.

Suction the LMA tube. There is no predictable continuum between the LMA tube and the glottic opening.53 A suction catheter will most likely not penetrate the trachea (for the same reason rescue medications administered through the LMA will not reach consistently the trachea). If the LMA fails (reduced chest wall movement, deteriorating O2SAT and ETCO2, increased airway pressure) other airway management options should be considered.
 

ILMA

·        Lubricate the tip of the tube.

·        Hold et tube at black line and insert and withdraw until lube on tube is totally spread, so there is no resistance. 

·        Lift and tilt back on handle until minimum air leak when ventilating, this is the position the tube should be passed in. 

 

ILA

Klein Maneuver

Pull back a few cm, jaw thrust, push forward

 

Chandy Maneuver

The Chandy maneuver (Figure 2) was developed by Dr. Chandy Verghese and significantly improves the effectiveness of the ILMA (25). It incorporates two maneuvers that improve lung ventilation and tracheal intubation using the ILMA. Part one of the Chandy maneuver facilitates positioning of the ILMA in the upper airway so that lung ventilation is maximized through the device. This is done by grasping the ILMA by the handle and moving it back and forth in the sagittal plane while observing the patient's tidal volume and/or the capnographic waveform (if ventilation is being controlled manually). However, if the patient is breathing spontaneously, an airway whistle (e.g., Patil intubation guide [Anesthesia Associates, San Marcos, CA] or Beck Airway Airflow Monitor [Great Plains Ballistics, Lubbock, TX]) can be attached to the proximal portion of the ILMA to optimize ventilation through it. The whistle will sound with each breath the patient takes. The ILMA is then moved slowly back and forth in the sagittal plane using part one of the Chandy maneuver until maximal whistling is attained. Maximal whistling indicates optimal positioning of the ILMA. The second part of the Chandy maneuver involves aligning the ILMA to facilitate smooth passage of the endotracheal tube (ETT) into the trachea.


A special Euromedical ETT is provided with the ILMA. The ETT has a longitudinal line, which should be oriented to face the patient's nose superiorly. Proper orientation of the longitudinal line causes the ETT to exit the ILMA at an angle that eases its passage into the trachea. The ETT also has a circumferential line at a distance from the distal tip of the ETT that is equal to the length of the ILMA from the proximal to the distal port. At the point where the circumferential line is advanced to the proximal port of the ILMA, the distal tip of the ETT will be in contact with the epiglottic elevator bar (which covers the distal port of the ILMA). The epiglottic elevator bar raises the epiglottis so that the ETT can enter the glottis unimpeded. Just before the distal tip of the ETT contacts the epiglottic elevator bar, the second part of the Chandy maneuver is performed. This involves lifting the handle of the ILMA at a 45° angle to the patient's chest. This helps align the trajectory of the ETT into the trachea inferiorly and usually facilitates smooth passage of the ETT into the trachea.
If the patient is breathing spontaneously, an airway whistle attached to the proximal end of the ETT will sound with each ventilation. As the tip of the ETT enters the trachea, the volume of the whistle increases. When the cuff of the ETT is inflated, the volume of the whistle will increase even more, heralding the sealing of the ETT within the trachea and securement of the patient's airway. Tracheal intubation should always be confirmed with an evidence-based method, using a carbon dioxide detector if the patient has a perfusing cardiac rhythm or a self-inflating bulb if the patient does not have a perfusing cardiac rhythm (39). Additionally, auscultation of bilateral breath sounds will confirm that the ETT is lying in a midtracheal position. The ILMA can then be removed over the ETT using the stabilizing rod (Figure 1) or left in place with the mask deflated until the trachea is extubated. (Proc Bayl Univ Med Cent 2005 July; 18(3): 220–227. James M. Rich, CRNA, MA)

 

The two steps of the Chandy maneuver. (a) After insertion of the LMA-Fastrach, optimal ventilation is established by slightly rotating the device in the sagittal plane, using the metal handle, until the least resistance to bag ventilation is achieved. This helps to align the internal aperture of the device with the glottic opening, (b) Just before blind intubation, the LMA-Fastrach is slightly lifted (but not tilted) away from the posterior pharyngeal wall using the metal handle. This prevents the endotracheal tube (ETT) from colliding with the arytenoids and facilitates the smooth passage of the ETT into the trachea. Reprinted from reference 25 with permission.
 

 

 


 

Laryngeal Tube

so