Focus on the Literature

   At each year's EMS State of the Sciences Conference, Nashville EMS medical director Corey Slovis, MD, presents his five most important EMS studies of the preceding year. Here are his top choices for 2010.

ACLS

   The evidence showing compression-only CPR works as well as the traditional version continues to mount, but there have been other important recent changes to CPR and emergency cardiovascular care. Major points of the 2010 international consensus treatment recommendations concern intubation, capnography, atropine, adenosine and therapeutic hypothermia. Some pearls:

• There's no evidence to support endotracheal tubes as better than supraglottic airways. Consider Kings, LMAs and Combitubes, especially without frequent retraining.
• Waveform capnography is recommended for ETT placement confirmation; colorimetric is acceptable.
• Atropine is no longer recommended for PEA or asystole.
• Adenosine may be useful for paroxysmal supraventricular tachycardia and can be used in regular monomorphic wide-complex tachycardias.

   Morrison LJ, Deakin CD, et al. 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. Circ 122(supp2): s345-421, 2010.

Bougie Use

   With a simulated difficult airway, Pennsylvania researchers found, bougie-assisted intubation is more successful than traditional ETI without increasing intubation time. In this study, 35 paramedics, flight nurses and emergency physicians randomly intubated a manikin both ways; using the bougie resulted in 94% success, ETI 77%. Half of subjects said using the bougie was easier, while just 9% preferred the ET tube.

   Messa MJ, Kupas DF, Dunham DL. Comparison of bougie-assisted intubation with traditional endotracheal intubation in a simulated difficult airway. Prehosp Emerg Care 15(1): 30-3, Jan 2011.

Oxygen and COPD

   Researchers in Tasmania compared standard high-flow oxygen to titrated oxygen for prehospital patients with acute exacerbation of chronic obstructive pulmonary disease. They found the risk of death was significantly lower in the titrated oxygen group for patients with COPD and overall. Overall mortality was 9% in the high-flow group vs. 4% in the titrated group; mortality in the COPD subgroup was 9% vs. 2% respectively. Titrated oxygen treatment reduced mortality compared with high-flow oxygen by 58% for all patients and by 78% for patients with COPD. Titrated COPD patients were also less likely to have respiratory acidosis or hypercapnia.

   Austin MA, Wills KE, Blizzard L, Walters EH, Wood-Baker R. Effect of high flow oxygen on mortality in chronic obstructive pulmonary disease patients in prehospital setting: randomized controlled trial. BMJ 341: c5462, 2010.

Easier Intubation

   What else can we do to make difficult airways easier? Recent literature has addressed ways to better intubate obese patients (two people/two hands, videoscope, early bougie/supraglottic, CPAP, ketamine); the two-handed jaw-thrust vs. one-handed "EC-clamp" technique for mask ventilation of unconscious and apneic patients (the former is superior); and a new position for intubation: the Alexandrou Angle, which elevates the supine patient's head 20°-30° in relation to the body and legs. Students in New York who tried different positions on manikins preferred this position to flat or Trendelenburg for visualizing the vocal cords.

   Dargin J, Medzon R. Emergency department management of the airway in obese adults. Ann Emerg Med 56(2): 95-104, Aug 2010.

   Joffe AM, Hetzel S, Liew EC. A two-handed jaw-thrust technique is superior to the one-handed "EC-clamp" technique for mask ventilation in the apneic unconscious person. Anesthesiology 113(4): 873-9, Oct 2010.

   Alexandrou NA, Yeh B, Barbara P, Leber M, Marshall LW Jr. An innovative approach to orotracheal intubations: The Alexandrou angle of intubation position. J Emerg Med 40(1): 7-13, Jan 2011.

Nasal Oxygen for Obese Patients

   Michigan researchers sought to evaluate the influence of nasal oxygen on the duration of arterial oxygen saturation of 95% or more during simulated difficult laryngoscopies on obese patients. Half of their 30 patients got additional nasal O2 during periods of apnea while anesthetized, and they measured duration of SpO2 greater than or equal to 95% up to a maximum of 6 minutes, as well as lowest SpO2 values and time to regain 100% SpO2.

   Their results: Giving the nasal O2 was associated with significant prolongation of SpO2 time of 95% or more; a significant increase in patients with apnea but SpO2 greater than or equal to 95% at 6 minutes; and significantly higher minimum SpO2. Resaturation times were no different. The nasal O2, they concluded, is associated with significant increases in frequency and duration of SpO2 greater than or equal to 95%, and higher minimum SpO2 during prolonged laryngoscopy in obese patients.

   Ramachandran SK, Cosnowski A, Shanks A, Turner CR. Apneic oxygenation during prolonged laryngoscopy in obese patients: A randomized, controlled trial of nasal oxygen administration. J Clin Anesth 22(3): 164-8, May 2010.