SAN DIEGO—What do you do when your obese, medically fragile patient presents profoundly short of breath? This was the scenario that Michael Winters, MD, MBA, FACEP, professor of emergency medicine and medicine at the University of Maryland School of Medicine in Baltimore, used to present current research in critical care medicine with significant relevance to the practice of the emergency medicine physician in his Monday session, “Cruising the Literature: Top Articles in Critical Care.”
Noninvasive ventilation (NIV) techniques such as bilevel positive airway pressure and continuous positive airway pressure are useful for cases of acute chronic obstructive pulmonary disease and congestive heart failure where patients are experiencing significant respiratory distress. However, in situations such as pneumonia, the delay caused by prolonged use of noninvasive ventilation to more definite airway management via endotracheal intubation, can result in higher intubation rates and worse 90-day mortality compared to patients who received high flow oxygen via nasal canula (. It appears that the patients who are most apt to benefit from early intubation are obese, remain tachypneic and tachycardic an hour after admission, and have high expiratory volume an hour (greater than 9 ml/kg predicted body weight) after implementing NIV.
Intubating a crash airway is fraught with risk, according to Dr. Winters. A randomized clinical trial reported in JAMA earlier this year indicated that the use of an endotracheal introducer or bougie stick in a first time intubation attempt resulted in a significantly higher success rate when compared to the traditional endotracheal stylet. This is especially true in patients with at least one difficult airway marker, such as obesity, obstructed airway or edema, short neck, or small mandible. A bougie may also be very helpful in situations where the glottis opening is partly obscured or where cervical precautions are present.
Many emergency physicians have experienced situations where patients arrest during intubation. An ICU study published in Critical Care Medicine indicated a 2.7 percent cardiac arrest rate occurred during the intubation procedure. Common predisposing factors included hypotension, hypoxemia prior to intubation, absence of preoxygenation, obesity, and age over 75 years. A comparison of 28-day mortality rates between intubated-related and nonintubated-related cardiac arrest showed a much higher rate among those who were intubated. The researchers concluded that intubation of a critically ill patient was an independent risk factor for 28-day mortality.
A pearl in critical care medicine is to “resuscitate before intubate,” said Dr. Winters. One very common resuscitation approach is volume resuscitation using a crystalloid fluid. A recent ICU study conducted by Vanderbilt University compared the outcomes of ICU patients who received normal saline versus those who received a balanced crystalloid such as lactated ringers or plasmalyte. Those who received a balanced solution were at less risk for a major adverse kidney effect compared to the saline group at 30 days, and experienced reduced mortality secondary to sepsis.
Epinephrine has been a mainstay of cardiac arrest resuscitation. A Paramedic-2 study published in NEJM may alter that practice. In the multicenter, randomized, double-blind, placebo-controlled study, while patients who received epinephrine compared to saline had higher admission and 30-day survival rates, there was no difference in favorable neurologic outcomes.
Exposure to early hyperoxia may also have an adverse impact to patient outcomes. A prospective cohort study conducted among six U.S. hospitals revealed post-arrest patients exposed to early hyperoxia, ie, in the emergency department, had much worse neurologic outcomes. Maintaining FiO2 levels between 92 and 97 percent can minimize the chance of hyperoxia.