(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)
(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 they talk?
Can they swallow and manage secretions?
SaO2 <90% on High Flow O2 or PaO2<60 on FiO2>40%
PaCO2 >55 if baseline is normal, or >10 increase from baseline
Respiratory Rate
Deterioration/Impending Compromise
Transport
Airway protection during procedures (ie. endoscopy)
Other Reasons include:
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.
· 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)
·
Look
at head and neck
·
Evaluate
·
Mallampati
· 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)
Restricted Mouth Opening
·
Evaluate
·
Mallampati
· 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.
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
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)
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
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)
10) qualitative determination; thick neck decreases ability to align upper airway planes
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)
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 16–18, 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)
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)
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)
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)
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)
|
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retreatment
· Tight Brain (Elevated ICP/Head Injury/CVA)
· Tight Vessels (Aortic Dissection/AAA)
· Tight Heart (ACS)
· Tight Lungs (Asthma)
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.
· Limit time of laryngoscopy
· Atraumatic laryngoscopy
Optimally, give premedications 3-5 minutes before RSI
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.
o Use in tight brain/tight vessels/tight heart to blunt catecholamine surge
o Fentanyl 3 ug/kg slow IVP
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
- 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
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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
· 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 usually spare pupils (Shah. Emergency Neurology,
p.5)
Succinylcholine
is the only one used in the
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:
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
Benzylsoquinolones-curare, atracurium. These cause histamine release
Aminosteroids
Vecuronium- Priming dose for vecuronium .01 mg/kg followed by .15 mg/kg will make it act quicker or use high dose vecuronium .3 mg/kg (Acta Anaes Scand 1993;37(5):465)
Pancuronium-Only if others not available
Rocuronium-ignore package dosing and use 1 mg/kg (46 min paralysis at this dose)
Gantacurium-new extremely short acting non-depolarizing???
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
|
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
Complications of emergency intubation with and without
paralysis. (Am J Emerg Med. 1999 Mar;17(2):141-3)
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rotection and Positioning
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)
· 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
|
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lacement and Confirmation
Wait till defasiculations cease if using Succinylcholine; flick the mandible to see if pt sufficiently blocked and
see below
·
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
· Primary assessment (Lung sounds) more for tube depth than confirming tracheal placement.
Self-Inflating Bulb-reliable even with uncuffed tubes (Acad Emerg Med April 2003, 10:4)
Can confirm depth by ballotment. Location of the
Endotracheal Tube by Pilot Balloon-Cuff
Counter-Ballottement (Anesth Analg. 1995 Jul;81(1):135-8)
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
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
Distally placed pulse ox has a 60-90 second lag from true
saturation
|
|
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
Assume hypoxia and therefore tube displacement until proven otherwise
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
· 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
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)
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
Position the patient
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
Control the Tongue
Control the Epiglottis
Landmark Recognition
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)
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)
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.
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.
Partial obstruction=wait for back up
Full
Back blows/chest thrusts
Look c McGill's
Push down mainstem with ET tube
Dangerous Equipment
0 Straight blade is too short for term and older infants, only for preemies.
#1 Curved blade is inappropriate for infants, straight blade much better
250 cc BVM, for newborns only
Cuffed ETs below size 5.5 Occasionally useful for asthmatics, but should not be in emergency airway carts
Large handle, too bulky for peds
Consider awake BNTI in a predicted difficult airway
start with 32 french trumpet anesthetize through it to get post pharynx
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
Give intubating dose of propofol, perform laryngoscopy, give paralytics if a good view is obtained
· 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
· Translaryngeal injection of 2-4 cc 4% lidocaine
· 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
· Glycopyrolate 0.2 mg IV
· Atropine .01 mg/kg IV
· 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)
Consider Scopolamine
Best choice these days is probably precedex (One series
Dexmedetomidine and Awake Fiberoptic Intubation for Possible Cervical
Spine Myelopathy: A Clinical Series.
Journal of Neurosurgical Anesthesiology. 17(2):97-99, April 2005.) also
now (Can J Anesth 2005; :776 Dexmedetomidine is a useful adjunct for awake
intubation)
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
Nearly Dead, Newly Dead
Still may consider using Sux if any muscle tone at all
Can't Intubate/Can't Ventilate or three failed attempts
Best Attempt Definition:
Performed by a reasonably experienced laryngoscopist
No significant muscle tone
Use of optimal sniff position
Use of external laryngeal manipulation
One change in length of blade
One change in type of blade
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]
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)
·
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)
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.
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.
· 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.
Pull back a few cm, jaw thrust, push forward
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.
so