Apneic oxygenation through a nasal cannula can help intubation in the ER, particularly by preventing low oxygen saturation (SO2) during intubation, according to a meta-analysis.
The eight-study meta-analysis, totaling 1,837 patients, also found that the technique increases the first-pass success rate of intubation.
“Apneic oxygenation is one of the few beneficial interventions that is inexpensive to administer,” said senior author M. Fernanda Bellolio, MD, research chair for the Department of Emergency Medicine at Mayo Clinic in Rochester, Minn.
Experts recommend apneic oxygenation for managing high-risk airway scenarios. “The relative simplicity and safety of the procedure, along with high success and low complication rates, had led to its widespread use,” Dr. Bellolio said. “In fact, some people consider apneic oxygenation to be standard of care, despite little evidence to support its value.”
Finding the Benefits
The purpose of the systematic review and meta-analysis, which was published in Annals of Emergency Medicine (2017;70:483-494), was to determine whether apneic oxygenation was helpful in an ER setting. “Not everyone uses this intubation technique in such a setting,” Dr. Bellolio said. “It is more common in the ICU and the operating room. ENT [ear, nose and throat] surgeons also often employ the technique when performing certain surgeries on the airway for continuous oxygen through the nose or through another pathway.”
The study found that apneic oxygenation during emergency intubation “is associated with increased peri-intubation oxygen saturation and first-pass success rates, as well as decreased incidence of hypoxemia in patients intubated in the emergency department or ICU,” Dr. Bellolio said.
The incidence of hypoxemia (SO2 <93%) was 17% among patients who received apneic oxygenation compared with 24.4% for standard intubation, according to the analysis. But there was no decrease in the rate of severe hypoxemia (SO2 <80%).
Similarly, the first-pass intubation success rate was 88% for apneic oxygenation versus 80% for standard intubation.
“It is reassuring that among nearly 2,000 patients, apneic oxygenation was advantageous,” Dr. Bellolio said. “Our results are in line with what we see in practice. These data apply to the emergency department and ICU, but not to the operating room. A patient who is intubated in the emergency department is different than most patients intubated in the operating room. The patient in the emergency room usually requires an urgent or emergent airway. It is never an elective intubation. These patients are also usually hemodynamically unstable. So I would not expect to see the same results in the operating room.”
A Solution Meant for the ER
Dr. Bellolio said apneic oxygenation is especially helpful for emergency departments with residents and other learners because the technique is safe and provides a longer apnea time and higher intubation success rate. “However, this intervention may not be needed for an expert intubator,” she said.
Although the analysis concluded that the oxygen level improved with apneic oxygenation, “we cannot prove that long-term outcomes were better,” Dr. Bellolio said. “It is unrealistic to expect that a short-term intervention will change long-term mortality.” Still, the analysis found that apneic oxygenation decreased ICU length of stay by 2.9 days.
Most of the evaluated studies of apneic oxygenation in the operating room were experimental in that they tried to ascertain how long a patient can function without extra oxygen. “These studies concluded that you can prolong the safe apnea time by up to 9 or 10 minutes,” Dr. Bellolio said.
The evidence of using apneic oxygenation in the operating room, however, was poor. “So with current evidence, I cannot recommend its use in the operating room setting,” Dr. Bellolio said.
One of the major limitations of the meta-analysis is the variation in preoxygenation and other peri-intubation techniques, as well as cointerventions. “These differences could impact the likelihood of developing hypoxemia during the apneic period,” Dr. Bellolio said.
Likewise, most of the evaluated studies did not describe techniques for the maintenance of airway patency during apneic oxygenation, “which could affect the quality of this intervention,” Dr. Bellolio said.
Nonetheless, apneic oxygenation for patients requiring emergency intubation “is a low-cost, universally available technique that can reduce the incidence of hypoxemia and increase first-pass intubation rates, and no adverse effects have been reported,” Dr. Bellolio said. “What all apneic oxygenation techniques have in common is that there is a focus on better peri-intubation techniques and better preoxygenation.”