Apneic Oxygenation During Airway Management in Pediatric Patients

This observational (i.e. nonrandomized) study aims to investigate the effect of a planned practice change; instituting oxygenation via nasal cannula during induction of anesthesia. The use of a nasal cannula during the peri-intubation period is of minimal risk and is not considered a standard of care in pediatric anesthesia. Some providers use it in certain clinical situations, but it is not broadly used and has virtually no pediatric literature to support or refute its use. At our institution, intubation of pediatric patients by inexperienced (learner) providers under expert supervision is routine. The attending physician intervenes if necessary before the patient experiences excessive loss of oxygenation.

Participants will be enrolled in the study once they have entered the pre-operative area and are determined by the attending anesthesiologist to be an eligible study participant. Participants enrolled in the first three months of the study (up to N=200) will be assigned to the baseline condition as described below. Participants enrolled in the second phase of the study (up to N=300) will be assigned to the with-cannula condition described below.

Apneic oxygenation is based on the physiology of the lungs: they absorb a greater volume of oxygen, 250 ml/min in an adult, than the volume of carbon dioxide, 8-20 mL/min, that is released by the lungs, because the majority of carbon dioxide is buffered in the blood stream during apnea. With the imbalanced volumes of absorption and release of gases in the lungs there is a lower than atmospheric pressure in the lungs, creating a passive movement of gases from pharynx to alveoli. If the gas in the pharynx has a significantly higher percentage of oxygen instead of room air at 21% oxygen, a higher amount of oxygen can be passively delivered to the lungs for absorption prolonging the time to hemoglobin desaturation.

For the Baseline Group of this observational (nonrandomized) study, all intubation procedures will be performed as per usual practice. Patients will receive premedication as determined by anesthesiologist/resident/midlevel. Once patients are brought to the operating room and vital signs are being monitored, patients will be preoxygenated via mask per standard of care, with an expired oxygenation concentration minimum of 0.75. Vitals will be recorded at the moment prior to removal of the face mask at the end of the preoxygenation period. Anesthetic induction will be performed with agents and dosages as per the provider's clinical judgment. Airway management consisting of oral endotracheal intubation or laryngeal mask airway insertion will take place. As per standard of care, an attending physician who is expert in pediatric airway management will supervise the procedure and intervene before the patient experiences excessive oxygen desaturation.

For the With-Cannula Group, all of the above steps will be maintained. The sole difference will be nasal cannula placement after induction. It will be set to deliver oxygen at 5 liters per minute. Airway management consisting of oral endotracheal intubation or laryngeal mask airway insertion will take place. As per standard of care, an attending physician who is expert in pediatric airway management will supervise the procedure and intervene before the patient experiences excessive oxygen desaturation.

Apneic oxygenation will not be used as a long-term oxygenation strategy. No patient will be allowed to become hypoxic for research reasons.

All intubation procedures in both study groups will proceed as per usual practice. The goal of all intubation procedures has always been and remains the maintenance of adequate oxygen saturation.

Inclusion criteria

• Pediatric patients presenting for surgery at University of New Mexico Children's Hospital
• Age range: adjusted gestational age 40 weeks, to 8 years

Exclusion criteria

• Patients whose airways would be maintained with mask ventilation only
• American Society of Anesthesiologists classes 4-6