This case was reported directly to SALG by the anaesthetist involved in the case

An elderly patient was referred for HoLEP. Apart from hypertension [the patient] was in reasonable health with a starting Hb of 14g/dl. [The patient] received sevoflurane/ N₂O based general anaesthesia, the trachea was intubated and an arterial line sited. The resection lasted approximately 3hrs. 365g of tissue was resected and blood loss was unremarkable. Approximately 200L of 0.9% saline was used for irrigation. The patient remained cardioivascularly stable throughout apart from an episode towards the end of the case. Prominent scleral oedema noticed. There was no significant hypoxia.

Arterial Blood Gas (ABG) taken once resection complete revealed a Hb 7, Cl 117 with a mild acidaemia. 2 units packed red cells were infused. Frusemide 40mg given intravenously as it was considered that excess fluid absorption was likely.

The patient was confused at the time of extubation but settled after 30mins, on arrival in post-operative recovery they reported some hearing loss in the right ear which persisted to discharge. ENT follow-up identified impaired hearing that was considered likely to be permanent.

Commentary:

This case has been shared with SALG’s partners at CORESS, to identify and publish the lessons in this case for surgery. Once this has taken place, we will include a link to their publication here.

As HoLEP is used to treat often very large prostates, resection times can be prolonged and there may be absorption of deleterious amounts of saline – the irrigation fluid used-   although in this case, it seems that more than the usual amount of saline was used.

The patient was given gentamicin in a dose routinely used for surgical prophylaxis- 160mg in divided doses over 5 minutes at induction- which is not associated with toxic levels. Therefore, this was considered unlikely to be the cause of the persistent hearing loss. Fluid overload during HoLEP has been shown to cause temporary hearing loss, and in this case, the patient probably developed cerebral oedema. The considerable drop in haemoglobin concentration was almost certainly due primarily to haemodilution. It is also likely that the patient had some pre-existing hearing loss, which is common in their age group, with a prevalence of 60-75%.

In order to minimise saline absorption, resection time should be limited, and two stage procedures may be needed. Whenever possible venous sinuses should not be breached. During resection, plasma chloride concentrations could be used to monitor absorption.^1,2

References:

1. Slots C, Uvin P, Van Damme E. Irrigation fluid absorption syndrome during HoLEP: A case study. Urol Case Rep, 2022; 45
2. Dodd SE, Jankowski CJ, Krambeck AE, Gali B. Metabolic acidosis with hemodilution due to massive absorption of normal saline as bladder irrigation fluid following holmium laser enucleation of prostate. J Anaesth, 2016; 30: 1060-2