Case
A 26-year-old female underwent endoscopic resection of a sinonasal alveolar rhabdomyosarcoma. Anaesthesia was initiated with propofol, remifentanil and rocuronium, and maintained with propofol and sevoflurane. Shortly after induction, the patient developed increased urine output >550 mL/hr, accompanied by rising serum sodium, osmolality and lactate which peaked at 5 hours after induction (Figure 1). The urine was dilute at 160 mosmol/kg. Five hours post-induction, the copeptin level was 0.8 pmol/L with a serum osmolality of 310 mosmol/kg and serum sodium of 154 mmol/L, consistent with AVP-deficiency (AVP-D).
Five hours and thirty-five minutes post-induction, one microgram of subcutaneous desmopressin was administered, resulting in reduction of urine output (Figure 1). She required a second dose twenty-three hours later.
Twenty-five hours post-induction, at least partial recovery was demonstrated with a copeptin of 4.1 pmol/L, serum osmolality of 285 mosmol/kg and serum sodium 140-143 mmol/L. Urine output was monitored for the following seventy-two hours with no further polyuria.
Discussion
Anaesthesia-induced AVP dysfunction is rare, but potentially life-threatening. Within the literature, there are two reported case of propofol-induced AVP dysfunction. Kassebaum et al. present a case demonstrating normalisation of urine output, plasma osmolality and plasma sodium following administration of desmopressin(1), supporting an AVP-D driven aetiology. In the case of the patient exposed to both sevoflurane and propofol, switching the anaesthetic agent to propofol caused a dramatic increase in urine output, while switching to sevoflurane resulted in prompt reduction(2). A potential mechanism is offered by murine models, in which propofol inhibited the secretory capacity of supraoptic nuclei cells(3). Case reports of sevoflurane-induced AVP dysfunction have not responded to desmopressin(4,5), suggesting a nephrogenic cause, possibly secondary to a transient decrease in aquaporin-2(6). Given the reported rapid response to discontinuation of causative anaesthetic agents(2,7), it may be a viable management option to switch the anaesthetic agent and monitor.