Sequential Spinal Anesthesia and Dexmedetomidine-Ketamine Infusion Preserving Spontaneous Ventilation in a Super-Obese Parturient (BMI 63.7 kg/m²) Undergoing Emergency Cesarean Section: An Observational Analytic Case Study

Abstract

Background. Cesarean delivery in super-obese parturients (body mass index [BMI] ≥ 50 kg/m²) carries a high risk of airway failure and hemodynamic instability, particularly with preeclampsia. When surgery outlasts a single-shot spinal anesthetic, conversion to general anesthesia adds a 'cannot intubate, cannot oxygenate' hazard.

Objective. To describe the cardiorespiratory course of a planned transition from spinal anesthesia to a dexmedetomidine-ketamine infusion in a super-obese parturient undergoing emergency cesarean section.

Methods. Single case report (CARE guideline). A 38-year-old woman (157 kg, 157 cm, BMI 63.7 kg/m², STOP-BANG 5, Mallampati class III) with preeclampsia and fetal hypoxia was followed across five operative epochs (T0 to T4) and postoperative surveillance (T5).

Results. Single-shot spinal anesthesia gave surgical conditions for 120 minutes. When the block regressed, dexmedetomidine (0.5 mcg/kg loading, then 0.5 mcg/kg/h) and ketamine (0.5 mg/kg loading, then 0.5 mg/kg/h) were started and spontaneous ventilation continued. During uterine atony with 2,000 mL blood loss, mean arterial pressure fell to 71.7 mmHg (−37.7% from 115.0 mmHg at baseline) and recovered with crystalloid, colloid, two units of packed red blood cells, uterotonics and norepinephrine, without intubation. The 4,025-g neonate recovered and was discharged on day 10. The mother had no hypoxemic episode, needed under 5 morphine milligram equivalents and was discharged on postoperative day 5.

Conclusion. In this patient, a planned spinal-to-infusion sequence was followed by spontaneous ventilation without airway instrumentation during a prolonged hemorrhagic cesarean delivery. This single observation needs confirmation in larger series.