Ryan Qasawa*, Semeret Munie and Keith Killu
Department of Surgery, Henry Ford Hospital, USAFulltext PDF
Background: Bradycardia during weaning from Mechanical Ventilation (MV) and Pressure Support Ventilation (PSV) is a rare occurrence, with only one such case report found in the literature. We present the case of a 23-year-old transgender (male to female) Abdominal Gunshot Wound (GSW) victim who developed significant bradycardia and sinus pause during PSV trial. Case Presentation: The patient presented to the Emergency Department with multiple GSWs to the abdomen. She was intubated for airway protection. Exploratory laparotomy was performed and patient underwent partial liver resection for liver lacerations and right hemidiaphragm injury. She remained intubated in the Surgical Intensive Care Unit (SICU) post-operatively and had multiple planned returns to the Operating Room (OR). On hospital day 9 the patient was on minimal MV settings, 0.8 mcg/kg/h of Dexmedetomidine, and 6 mg/h of Morphine. Continuous Positive Airway Pressure (CPAP) and PSV trial was initiated, pressure Support (PSupp) 7 cm H2O and Positive End Expiratory Pressure (PEEP) 5 cm H2O. Immediately, the patient became bradycardic and had a sinus pause for approximately 15 sec, at which point the ventilator mode was switched back to Pressure Regulated Volume Control (PRVC), and the patient instantly converted back to Normal Sinus Rhythm (NSR) 70 to 90 beats per minute. The following day, another CPAP trial was performed after stopping all sedation, which again resulted in episode of bradycardia and pause, reverting to NSR after being placed back on PRVC. The patient self-extubated ahead of the third CPAP trial, on 20 mcg/kg/h of Propofol and 1.2 mcg/kg/h of Dexmedetomidine. She became bradycardic to 30 to 40 beats per minute for approximately 10 sec, and spontaneously returned to NSR 70 to 80 beats per minute. Conclusion: MV setting alterations during weaning procedures have direct effects on patient hemodynamics, due to effect on intrathoracic pressure and the autonomic nervous system. The decreased airway pressure during CPAP and PSV trials or immediately after extubating produces an increase in cardiac output due to decreased intra-thoracic pressure and thus, increased venous return to the right atrium. This, in turn, causes an increase in parasympathetic output, which may cause profound bradycardia or sinus pause.
Bradycardia; Weaning; Ventilator; Critical care
Qasawa R, Munie S, Killu K. Bradycardia and Sinus Pause with Pressure Support Ventilation and Weaning from Mechanical Ventilation. Ann Clin Case Rep. 2020; 5: 1881..