Inadvertent
ventilator triggering can occur for various reasons. Leaks in the
ventilator circuit, endotracheal tube leaks, tracheal cuff leaks, cardiac oscillations, water condensate causing oscillations in the circuit tubing,
ventilator expiratory valve integrity, and overly sensitive triggering mechanism settings may precipitate this phenomena. We present a case of inadvertent
ventilator triggering caused by electrical stimulation of the diaphragm from surgically placed pacing wires post cardiothoracic surgery. A 47-year-old woman underwent surgical placement of a left (LVAD) and right (RVAD)
ventricular assist device for severe end stage
cardiomyopathy, as a bridge to
cardiac transplantation. The patient was observed to have inadvertent
ventilator triggering while deeply sedated postoperatively. The
ventilator set respiratory rate was 16 breaths/min, with patient respiratory rate of 30 breaths/min while deeply sedated. Upon assessment of
ventilator waveforms and arterial blood gas revealing a profound
respiratory alkalosis, the pressure/time waveform demonstrated a -2 cm H(2)O decrease in pressure prior to each cycled breath. The
ventilator was subsequently changed from flow trigger sensitivity of 3 L/min to pressure trigger sensitivity of -3 cm H(2)O to eliminate the autotriggering. Later in the patient's ICU stay, inadvertent
ventilator triggering was again observed. Further adjustment of the pressure trigger sensitivity to -3 cm H(2)O eliminated the autotriggering. Clinical assessment found the pacing wires were responsible for stimulating the patient's diaphragm, therefore causing airway pressure decreases and premature breath delivery. Once the electrical amplitude of the pacemaker was decreased, the inadvertent
ventilator triggering resolved and normal trigger sensitivity and pH was restored.