P039: CARDIOVASCULAR COLLAPSE DURING CESAREAN DELIVERY - WHEN TOO MUCH AIR BECOMES A PROBLEM
Juan Mora, MD, Brooke Ingram, MD; University of Florida - Jacksonville
Introduction: Venous Air Embolism (VAE) a preventable but serious complication, occurs as a result of a pressure gradient between the atmosphere and the venous vasculature that allows air to enter the blood stream.
A small amount of air inside the venous compartment can be easily absorbed, giving no symptoms to the patient. However, in larger doses (3-5ml/kg) it can produce circulatory arrest due to occlusion of the right outflow tract with a mortality rate above 50%.
Diagnosis and monitoring can be done via transesophageal echo, precordial doppler, end-tidal nitrogen, and less accurately by end-tidal CO2. The management depends on the severity of the symptoms and the surgical team should be informed as they can contribute by decreasing the air entrance. In addition, nitrous oxide should be discontinued and 100% oxygen should be delivered to the patient. If needed, CPR should be started along with hemodynamic and ventilatory support.
The incidence of VAE during cesarean delivery is underreported but has been described to be 26-97%. It usually occurs after the delivery and the closure of the hysterotomy. Hypovolemia, deep inspiration, an operative site located at 5 or more centimeters above the right atrium, Trendelenburg position, exteriorization of the uterus, abruptio, placenta previa and uterine incision-to-delivery time higher than 30 seconds were all related with a higher risk for VAE.
Case description: 29-year-old P4G3A0 female with PMH of chronic hypertension, sickle cell trait, and 3 prior cesarean deliveries (requiring general anesthesia in 2 of them due to the failure of neuraxial technique). Her mother died at age 29 due to unspecific “cardiac reasons”.
She presented for elective repeated C-section at 39 weeks of gestational age. ASA monitors placed and a combined spinal-epidural technique was used with adequate analgesia and no complications. A uterine incision was made and a viable male neonate and placenta were delivered and the uterus was exteriorized and cleaned. Once the obstetrical team started to repair the uterine incision, the patient suddenly became unresponsive with agonal breath, PEA was noted and ACLS protocol commenced, 4 rounds of chest compressions provided, 1mg of IV epinephrine given and an endotracheal tube was placed. Having return of spontaneous circulation to sinus tachycardia after 5 minutes of CPR. The surgical procedure was completed and the patient was transferred to MICU. Head and chest CT, echocardiogram, lower extremities Doppler, EKG, EEG, ABG, and electrolytes, were all within normal limits. The patient was extubated on postoperative day 1, hemodynamically stable, neurologically intact and amnestic to the event. She was discharged home on postoperative day 4.
Conclusion: Females undergoing cesarean delivery are at high risk of having a VAE event. Adequate perioperative monitors aimed to detect VAE are rarely used, and because the majority of the times the amount of air is not big enough, the patients remain asymptomatic and the VAE episode is unrecognized. Special precautions and preventive actions should be taken to avoid an unfortunate bad outcome, active communication with the patients and the obstetrical team is necessary for the adequate management of this situations.