Managing passive regurgitation in patients under general anaesthesia

Regurgitation is the passive retrograde migration of acidic gastric contents into the oropharynx and/or nasopharynx (Figures 1 and 2). Gastro-oesophageal reflux differs from regurgitation, in that it is the ‘silent’ passage of gastric contents into the oesophagus, and often goes unnoticed as the stomach contents cannot be visualised (Table 1). Subclinical reflux into the oesophagus may occur in up to 55% of anaesthetised patients (Wilson et al, 2005). Patients who experience regurgitation must have already experienced gastro-oesophageal reflux.

The severity of complications depends on the immediate management of the episode and can include oesophagitis, rhinitis, aspiration pneumonia, oesophageal stricture and, in some cases, death.

Regurgitation has been reported to occur between 0.4–5.5% of dogs (Raptopoulos and Galatos, 1997; Wilson et al, 2006). Gastro-oesophageal reflux happens when the effectiveness of the lower oesophageal sphincter is decreased, usually by administration of anaesthetic agents. It has been documented to occur post pre-medication, intra-operatively and postoperatively. The causes for reflux and regurgitation are likely to be related (Galatos et al, 2001). They can also cause the same complications (with the exception of aspiration pneumonia for reflux, as the gastric contents enter only the oesophagus).