Minh Le Cong is a frequent guest and commenter on EMCrit. I have asked him, whenever inspiration strikes, to write guest posts on the blog. Minh is an airway guru and can share the unique perspective of a doc doing prehospital retrieval and care. Here's Minh:
Oxygenation with a needle cricothyrotomy based technique:
I want to provide a host of reference articles for you to decide for yourself the science and the practicality in the cannot intubate/cannot oxygenate scenario. The astute reader will note the crucial difference between total upper airway obstruction model of research and the partially obstructed or unobstructed airway model. High pressure, high flow via a needle catheter carries a low safety index with the margin between safe oxygenation and lethal barotraumas being narrow. Short inspiratory times and long expiratory times ( ratio of more than 1:4 and ideally 1: 9) appear to be safest. In the more common situation of a partially obstructed or unobstructed airway but a failed intubation, failed BVM oxygenation and critical hypoxia, high flow oxygenation via a 14 G needle cannula is practical and much safer as pressure is released via the upper airway.
In his article, Patel describes successful repeat intubation in more than half of the rescue oxygenated patients using the needle cricothyroidotomy technique, avoiding the open surgical technique completely. Low flow transtracheal insufflations of oxygen at 2 l/min as demonstrated by the research Black, Janus and Grothwohl is even safer yet capable in their animal model of rescue oxygenating successfully for at least 1 hr. There are multiple case reports in the literature of human patients being successfully rescued using the needle catheter technique with a variety of improvised as well as dedicated transtracheal oxygenation setups. The reader must decide for themselves but it needs to be pointed out that the needle catheter technique is the only one that is most applicable across all age groups, with open surgical technique in children being even less practiced than in adults!
References compiled by Dr. Minh Le Cong, Jan 2012-01-02:
Patel RG. Percutaneous transtracheal jet ventilation: a safe, quick, and temporary way to provide oxygenation and ventilation when conventional methods are unsuccessful. Chest. 1999 Dec; vol. 116(6) pp. 1689-94. PMID: 10593796
Based on the subsequent insertion of an endotracheal tube into the trachea, there were two important benefits in the patients who underwent PTJV successfully. First, PTJV provided effective oxygenation, while allowing adequate time for upper airway visualization and possible suctioning of oropharyngeal secretions. Second, tracheal intubation was subsequently easier, possibly because the high tracheal pressure from the gas insufflation opened the collapsed glottis, making visualization of the glottic aperture better. PTJV is safe and quick in providing immediate oxygenation, and therefore should be considered as an alternative to insistent, multiple intubation attempts, when neither bag-mask-valve ventilation nor endotracheal intubation is feasible in providing adequate gas exchange.
Black IH, Janus SA, Grathwohl KW. Low-flow transtracheal rescue insufflation of oxygen after profound desaturation. PMID: 16294073
Low-flow TRIO rescued animals from profound hypoxia and maintained oxygenation for at least 1 hour. Low-flow TRIO did not prevent hypercarbia with its subsequent sympathetic activation.
Ayoub IM, Brown DJ, Gazmuri RJ. Transtracheal oxygenation : an alternative to endotracheal intubation during cardiac arrest. Chest. 2001 Nov; vol. 120(5) pp. 1663-70 PMID: 11713151
TTO was as effective as conventional positive-pressure ventilation with 100% O(2) for securing oxygenation, resuscitation, and short-term survival and more effective than O(2) delivered through a mask.
Jawan B, Cheung HK, Chong ZK, Poon YY, Cheng YF, Chen HS, Huang CJ, Lee JH. Aspiration in transtracheal oxygen insufflation with different insufflation flow rates during cardiopulmonary resuscitation in dogs. Anesth. Analg. 2000 Dec; vol. 91(6) pp. 1431-5
We investigated whether transtracheal insufflation of oxygen with different insufflation flow rates protects against aspiration of gastric contents during cardiopulmonary resuscitation (CPR). Its ventilation and oxygenation effects were also evaluated. Cardiac arrest was induced in anesthetized and paralyzed 18 mongrel dogs. Chest compression using an automatic thumper was performed while the dogs randomly received no mechanical ventilation (Group I, n = 6) or were transtracheally insufflated with 4 L/min oxygen (Group II, n = 6) or 10 L/min oxygen (Group III, n = 6). Blood samples were drawn every 5 min for 20 min for blood gas analysis. the mouths of the dogs were then filled with 70 mL mixed barium, and 10 min after chest compression, chest radiographs were taken to evaluate the incidence of pulmonary aspiration. Results showed that pulmonary aspiration occurred in all dogs of Group I and three of the six dogs in Group II, whereas dogs in Group III were free from pulmonary aspiration. Both transtracheal oxygen insufflation groups maintained oxygen saturation significantly better than Group I, but mild hypercapnia was observed in all groups after 20 min of CPR. We conclude that transtracheal oxygen insufflation, but not chest compression alone, was able to maintain oxygenation for 20 min during CPR in dogs with cardiac arrest. Mild hypercapnia was noted in all groups. Chest compression alone caused pulmonary aspiration, whereas insufflation of 10 L O(2)/min provided better protection against pulmonary aspiration than that of 4 L O(2)/min.
Stothert JC, Stout MJ, Lewis LM, Keltner RM. High pressure percutaneous transtracheal ventilation: the use of large gauge intravenous-type catheters in the totally obstructed airway.Am J Emerg Med. 1990 May; vol. 8(3) pp. 184-9. PMID: 2331256
Percutaneous transtracheal ventilation using a large gauge intravenous-type catheter can be used successfully in the setting of complete upper airway obstruction in animals. In this study, using a large animal model, satisfactory oxygenation and ventilation was achieved by inversely varying the catheter size and the inspiration to expiration ratio (I:E). Specifically, 30 to 63 kg ruminants with an obstructed upper airway were resuscitated for 30 minutes from a hypoxic, hypercarbic, and acidotic state using 12- and 14-gauge catheters connected to a 50 psi oxygen source via a two-way valve with an I:E of 1:4 and 1:9 seconds, respectively. Shorter expiratory time or increased inspiratory time with these intravenous catheters resulted in significant hemodynamic compromise, barotrauma, inadequate carbon dioxide elimination, acidemia, and frequent death.