The Effect of the Preoperative Fasting Regimen on the Incidence of Gastro-Oesophageal Reflux in 90 Dogs

Abstract

This study aimed to investigate the effect of three different preoperative fasting regimens on the incidence of gastro-oesophageal reflux (GOR) in dogs under general anaesthesia. Ninety dogs undergoing non-abdominal and non-thoracic elective surgery were included in the study and equally allocated to three groups. Dogs received canned food providing half the daily resting energy requirements (RER) 3 h prior to premedication (group 3H), a quarter of the daily RER 3 h before premedication (group 3Q), and half the daily RER 12 h before premedication (group 12H). The animals were premedicated with acepromazine and pethidine, anaesthesia was induced with propofol and maintained with isoflurane vaporised in oxygen. Oesophageal pH was monitored throughout anaesthesia. Demographic and surgery-related parameters were not different among groups. The incidence of GOR was 11/30 in group 3H (36.7%), 9/30 in group 3Q (30.0%) and 5/30 in group 12H (16.7%), which was not statistically different (p = 0.262). Reduction of the amount of the preoperative meal from half to a quarter of the daily RER did not reduce the incidence of GOR but resulted in a lower oesophageal pH (p = 0.003). The results of this study suggest that the administration of a meal 3 h before anaesthesia does not have any beneficial effect in the reduction of GOR incidence in dogs compared to the administration of a meal 12 h before anaesthesia.

Factors Affecting Intraoperative Gastro-Oesophageal Reflux in Dogs and Cats

“…Because of the high heterogeneity, the four publications were rigorously inspected. It was obvious that two of them (Viskjer et al [14] and Tsompanidou et al [47]) were in favour of >5 h fasting, whereas the other two (Galatos et al [10] and Savvas et al [15]) were in favour of <5 h fasting. The main difference between these two groups of publications was the use of opioids in the anaesthetic protocol.…”

“…Overall, 4 out of 13 studies on dogs investigated the effect of preanaesthetic fasting on GOR (Table 1) [10,14,15,47], 1/13 studies was about the effect of induction agents on GOR (Table 2) [42], 1/13 studies was about the effect of inhalant agents for the maintenance of anaesthesia on GOR [22] (Table 3), 1/13 was about the effect of morphine on GOR [6] (Table 4), 3/13 were about the effect of antacids on GOR [12,39,40] (Table 5), Overall, 4 out of 13 studies on dogs investigated the effect of preanaesthetic fasting on GOR (Table 1) [10,14,15,47], 1/13 studies was about the effect of induction agents on GOR (Table 2) [42], 1/13 studies was about the effect of inhalant agents for the maintenance of anaesthesia on GOR [22] (Table 3), 1/13 was about the effect of morphine on GOR [6] (Table 4), 3/13 were about the effect of antacids on GOR [12,39,40] (Table 5), 2/13 were about the effect of metoclopramide on GOR [13,43] (Table 6), and 1/13 was about the effect of maropitant on GOR [41] (Table 7). One out of two studies in cats investigated the effect of omeprazole on GOR [44], and the other one investigated the effect of induction agents on GOR [20] (Table 8).…”

“…The remaining six groups of >5 h fasting were merged into one group, in order for this paper to be included in the meta-analysis. In the publication by Tsompanidou et al [47], the dogs had been allocated into three groups, two with a <5 h fasting and one with >5 h fasting. In order to include this paper in the meta-analysis, the two <5 h groups were merged into one.…”

“…Thus, a sensitivity analysis (subgroup analysis) was performed, which revealed a statistically significant difference between the subgroups (chi 2 = 14.11, df = 1, p = 0.0002, I 2 = 92.9%). When opioids were used (Viskjer et al [14] and Tsompanidou et al [47]), the overall effect was statistically significant in favour of >5 h fasting (z = 2.40, p = 0.02, odds ratio = 2.98, 95% CI 1.22, 7.30), with low heterogeneity (tau 2 = 0.17, chi 2 = 1.67, df = 1, p = 0.20, I 2 = 40%), whereas when opioids were not used (Galatos et al [10] and Savvas et al [15]) the overall effect was statistically significant in favour of <5 hours fasting (z = 2.9, p = 0.004, odds ratio = 0.17, 95 CI 0.05, 0.56), again with very low heterogeneity (tau 2 = 0.00, chi 2 = 0.65, df = 1, p = 0.42, I 2 = 0%).…”

“…Animals 2022, 12, x 10 of 17 by Tsompanidou et al [47], the dogs had been allocated into three groups, two with a <5 hours fasting and one with >5 h fasting. In order to include this paper in the meta-analysis, the two <5 h groups were merged into one.…”