Factors Affecting Intraoperative Gastro-Oesophageal Reflux in Dogs/Cats: History
View Latest Version
Please note this is an old version of this entry, which may differ significantly from the current revision.
Subjects: Veterinary Sciences
Contributor:
Ioannis Savvas

Gastro-oesophageal reflux (GOR) is an anaesthetic complication that causes oesophageal inflammation and stricture in animals. There are many factors affecting the development of GOR during anaesthesia in dogs. Evidence in cats is even more scarce. More studies are necessary for safer conclusions.

  • anaesthesia
  • cat
  • dog
  • gastro-oesophageal reflux

1. Introduction

Gastro-oesophageal reflux (GOR) is the “silent” movement of gastric and/or duodenal contents into the oesophagus without associated eructation or vomiting, and can lead to oesophageal mucosal injury and oesophagitis in dogs and cats [1][2]. Anaesthetic agents seem to reduce the lower oesophageal sphincter (LOS) tone and this is a major factor involved in the pathogenesis of reflux [3][4][5]. The refluxate in the oesophagus can originate only from the stomach (acid reflux) or can be a mixture of gastric and duodenal contents (non-acid reflux) [6]. The incidence of GOR during anaesthesia has been investigated by the measurement of oesophageal pH. GOR occurs when the effectiveness of LOS is decreased by anaesthetic agents, gastric acidity and food withholding [3][4][5][7].
As GOR is thought to be the main cause of oesophageal inflammation and stricture in animals, it can lead to death or euthanasia [8][9]. During general anaesthesia, GOR is a common complication that occurs in 4.8% to 66.7% of dogs [6][10][11][12][13][14][15][16]. According to the literature, there are many factors that contribute to the development of GOR, such as preoperative food withholding, volume and acidity of the gastric contents, age, type of the surgical procedure, positioning of the patient and anaesthetic agents [6][10][15][17][18][19][20][21][22].
In humans, pulmonary aspiration following GOR is one of the most common causes of death related to anaesthesia. Over the years, a lot of research has been conducted to establish fasting guidelines prior to anaesthesia to reduce the risk of GOR. The traditional guideline was nil by mouth (NPO) from midnight if the surgery was scheduled for the morning, and toast with a tea (light breakfast) for the patients who were scheduled for the afternoon [23][24][25].
Thirteen years ago, the American Society of Anesthesiologists (ASA) adopted the guideline of a 6 h fast from solids and 2 h fast from clear liquids prior to an anaesthetic procedure [26][27]. Moreover, the Canadian Anaesthetists’ Society recommends a total fast of no less than five hours and suggests that policies be constructed within individual departments [28].
In human medical literature, there are two large systematic reviews with meta-analyses in the Cochrane Collaboration on preoperative fasting. According to the first one, there is no evidence that a shortened fluid fast can increase the risk of aspiration, regurgitation, or mortality compared to the standard NPO fasting practice in adults [29]. In the second one on preoperative fasting in children, no evidence was found that children who do not receive any fluids for more than 6 h preoperatively benefit compared to the children who had free access to fluids for up to 2 h preoperatively [30].
Another factor that seems to affect the development of GOR in humans is the volume and acidity of gastric content (GC), and several reports have investigated a potential correlation between them [31][32][33][34][35][36][37][38]. According to Hardy et al. [37], there is no correlation between the GC volume and the incidence of reflux at induction of anaesthesia. Moreover, it has been reported that a prolonged duration of fasting does not guarantee a decrease in the volume of GC, and a light breakfast 2–3 h before surgery does not change the pH and the volume of GC [31].
In dogs, although there are no clearly proposed fasting guidelines before induction of anaesthesia, there is evidence that an increased duration of preoperative fasting may cause a high incidence of GOR [10][15][18]. Other suggested guidelines are withholding of food and water for approximately 12 h before surgery [10][12][13][21][39][40][41][42] or overnight [6][22][43]. Furthermore, the effect of various types of food given on two different preoperative fasting times, 3 or 10 h beforehand, on GC volume and acidity has been studied in dogs. It suggests that feeding dogs with canned food at a half daily rate 3 h before anaesthesia nonsignificantly increased the GC volume, while the GC acidity decreased significantly [18].
On the other hand, in a recent study by Viskjer et al. [14], a 3 h fasting period was associated with significantly greater odds for reflux compared to an 18 h fasting period. However, the pH of the refluxate was significantly higher in the 3 h fasting group. Another study in which the dogs were fed with canned food at half daily rate 12 h before the induction of anaesthesia reported an overall incidence (44.1%) of GOR in dogs [16].
A factor that seems to affect the incidence of GOR in dogs is the different types of drugs (anaesthetic/nonanaesthetic agents). Studies have investigated the effect of opioids such as morphine [6] and pethidine [21], injectable anaesthetic agents, (propofol and thiopentone) [42], inhalant anaesthetic agents, (halothane, isoflurane and sevoflurane) [22] on the incidence of GOR. Except for these agents, other drugs have also been investigated for their impact on GOR in dogs, such as D2 receptor antagonists [13][43], antiemetics [41] and antacids [12][39][40].
In anaesthetized cats, there is little evidence about the effect of different drugs on the LOS and on the incidence of GOR. There are studies investigating the effect of acepromazine, atropine, pethidine [4], propofol, thiopentone, alphaxalone, ketamine and xylazine [3] on LOS, and other studies about the action of induction agents [20] and antacids [44] on GOR.

2. Factors Affecting Intraoperative Gastro-Oesophageal Reflux in Dogs/Cats

The fasting duration before anaesthesia seems to be an important factor that influences the incidence of GOR, and there is a lot of discussion about the proper fasting guidelines in humans and animals. In the study by Galatos et al. [10], an increased duration of preoperative fasting was associated with a high incidence of reflux. The clinical study by Savvas et al. [15] is also in favour of fasting duration less than 5 h. These findings are in agreement with the GOR incidence discussed in another study, investigating the effect of fasting on GC volume and pH, in which the administration of canned food at half daily rate 3 h before anaesthesia increased the risk of GOR is dogs, but this would be an effect of chance alone (nonsignificant effect) [18].

In contrast, two other studies (Viskjer et al. [14] and Tsompanidou et al. [45]) revealed a totally different outcome. A light meal 3 h before anaesthesia was associated with a significantly higher incidence of GOR in comparison with overnight food withholding. The authors of the first study (Viskjer et al. [14]) gave some explanations as to why their results differed from other studies. The large volume of the meal and the different composition of food (the amount of proteins and fibres were higher in comparison with the food in the study by Savvas et al. [18]) may have been responsible for the different findings in comparison with the other two studies. Moreover, the administration of an opioid as preanaesthetic medication in combination with the amount and type of food may influence gastric motor function. Another important point in the design is that the dogs that underwent pelvic limb surgery received an additional dose of morphine epidurally prior to surgery. All these limitations could explain the different findings in that study regarding the appropriate duration of fasting. Likewise, in the other study (Tsompanidou et al. [45]) pethidine was used to premedicate the dogs. From the subgroup analysis, it seems that the use of opioids in the anaesthetic protocol may lead to a threefold increase in the risk of GOR. It has been shown that opioids can induce GOR [6][21], so clinicians must always bear in mind this effect when they use opioids.

Not only antacids but also antiemetics, such as maropitant, and D2 receptor antagonists, such as metoclopramide, influence the incidence of GOR. The findings on the effect of metoclopramide on GOR during anaesthesia are different between the two relevant studies by Favarato et al. [13] and Wilson et al. [43]. The lack of a beneficial effect of metoclopramide alone or with ranitidine in preventing GOR in the study by Favarato et al. [13] may be due to the anaesthetic protocol used, which was not anticipated to contribute to a high occurrence of GOR, as an opioid was not included. Their findings are in contrast to the results of the study by Wilson et al. [43], which showed a reduced risk of GOR after the administration of metoclopramide, however morphine was part of the anaesthetic protocol as preanaesthetic medication in the study by Wilson et al. [43].

Different induction agents, thiopentone and propofol [42], or different inhalant agents for the maintenance of anaesthesia halothane, isoflurane and sevoflurane [22], seem to affect GOR differently, but a definite conclusion cannot be drawn.

Regarding the opioids, contradictory results have been reported by different studies. There is little evidence on the effect of opioids on GOR. Only two studies have been published on the effect of morphine [6] and pethidine [21] on GOR in dogs. Morphine increases the incidence of GOR during anaesthesia, while the use of pethidine decreases the incidence of GOR when compared to morphine premedication [21]. In the study on morphine, a prolonged period of food withholding (10–30 h) was implemented, and this may have contributed to the high incidence of GOR [6]. The food was withheld from the dogs for a mean of 18 h prior to anaesthesia and this is in agreement with other studies [10][19]. However, no animal that had a fasting duration between 2–4 h, had an episode of GOR. So, it seems that the association between fasting duration and the effect of morphine on GOR is a subject that requires further investigation.

This entry is adapted from the peer-reviewed paper 10.3390/ani12030247

References

  1. De Miguel Garcia, C.; Pinchbeck, G.; Dugdale, A.; Senior, J. Retrospective Study of the Risk Factors and Prevalence of Regurgitation in Dogs Undergoing General Anaesthesia. Open Vet. Sci. J. 2013, 7, 6–11.
  2. Raptopoulos, D.; Galatos, A.D. Post anaesthetic reflux oesophagitis in dogs and cats. Vet. Anaesth. Analg. 1995, 22, 6–8.
  3. Waterman, A.E.; Hashim, M.A. Effects of thiopentone and propofol on lower oesophageal sphincter and barrier pressure in the dog. J. Small Anim. Pract. 1992, 33, 530–533.
  4. Hashim, M.A.; Waterman, A.E. Effects of thiopentone, propofol, alphaxalone-alphadolone, ketamine and xylazine-ketamine on lower oesophageal sphincter pressure and barrier pressure in cats. Vet. Rec. 1991, 129, 137–139.
  5. Hashim, M.A.; Waterman, A.E. Effects of acepromazine, pethidine and atropine premedication on lower oesophageal sphincter pressure and barrier pressure in anaesthetised cats. Vet. Rec. 1993, 133, 158–160.
  6. Wilson, D.V.; Evans, A.T.; Miller, R. Effects of preanesthetic administration of morphine on gastroesophageal reflux and regurgitation during anesthesia in dogs. Am. J. Vet. Res. 2005, 66, 386–390.
  7. Strombeck, D.R.; Harrold, D. Effects of atropine, acepromazine, meperidine, and xylazine on gastroesophageal sphincter pressure in the dog. Am. J. Vet. Res. 1985, 46, 963–965.
  8. Adamama-Moraitou, K.K.; Rallis, T.S.; Prassinos, N.N.; Galatos, A.D. Benign esophageal stricture in the dog and cat: A retrospective study of 20 cases. Can. J. Vet. Res. 2002, 66, 55–59.
  9. Wilson, D.V.; Walshaw, R. Postanesthetic Esophageal Dysfunction in 13 Dogs. J. Am. Anim. Hosp. Assoc. 2004, 40, 455–460.
  10. Galatos, A.D.; Raptopoulos, D. Gastro-oesophageal reflux during anaesthesia in the dog: The effect of preoperative fasting and premedication. Vet. Rec. 1995, 137, 479–483.
  11. Anagnostou, T.L.; Savvas, I.; Kazakos, G.M.; Ververidis, H.N.; Haritopoulou, M.R.; Rallis, T.S.; Raptopoulos, D. Effect of endogenous progesterone and oestradiol-17β on the incidence of gastro-oesophageal reflux and on the barrier pressure during general anaesthesia in the female dog. Vet. Anaesth. Analg. 2009, 36, 308–318.
  12. Panti, A.; Bennett, R.C.; Corletto, F.; Brearley, J.; Jeffrey, N.; Mellanby, R.J. The effect of omeprazole on oesophageal pH in dogs during anaesthesia. J. Small Anim. Pract. 2009, 50, 540–544.
  13. Favarato, E.S.S.; Souza, M.V.V.; Costa, P.R.S.R.S.; Favarato, L.S.C.S.C.; Nehme, R.C.C.; Monteiro, B.S.S.; Bonfá, L.P.P. Evaluation of metoclopramide and ranitidine on the prevention of gastroesophageal reflux episodes in anesthetized dogs. Res. Vet. Sci. 2012, 93, 466–467.
  14. Viskjer, S.; Sjöström, L. Effect of the duration of food withholding prior to anesthesia on gastroesophageal reflux and regurgitation in healthy dogs undergoing elective orthopedic surgery. Am. J. Vet. Res. 2017, 78, 144–150.
  15. Savvas, I.; Raptopoulos, D.; Rallis, T. A “Light Meal” Three Hours Preoperatively Decreases the Incidence of Gastro-Esophageal Reflux in Dogs. J. Am. Anim. Hosp. Assoc. 2016, 52, 357–363.
  16. Flouraki, E. The Effect of Premedication on the Incidence of of Gastroesophageal Reflux during General Anesthesia in the Dog; Aristotle University of Thessaloniki: Thessaloniki, Greece, 2017.
  17. Waterman, A.E.; Hashim, M.A.; Pearson, H. Effect of body position on oesophageal and gastric pressures in the anaesthetised dog. J. Small Anim. Pract. 1995, 36, 196–200.
  18. Savvas, I.; Rallis, T.; Raptopoulos, D. The effect of pre-anaesthetic fasting time and type of food on gastric content volume and acidity in dogs. Vet. Anaesth. Analg. 2009, 36, 539–546.
  19. Galatos, A.D.; Raptopoulos, D. Gastro-oesophageal reflux during anaesthesia in the dog: The effect of age, positioning and type of surgical procedure. Vet. Rec. 1995, 137, 513–516.
  20. Galatos, A.D.; Savas, I.; Prassinos, N.N.; Raptopoulos, D. Gastro-Oesophageal Reflux during Thiopentone or Propofol Anaesthesia in the Cat. J. Vet. Med. Ser. A Physiol. Pathol. Clin. Med. 2001, 48, 287–294.
  21. Wilson, D.V.; Tom Evans, A.; Mauer, W.A. Pre-anesthetic meperidine: Associated vomiting and gastroesophageal reflux during the subsequent anesthetic in dogs. Vet. Anaesth. Analg. 2007, 34, 15–22.
  22. Wilson, D.V.; Boruta, D.T.; Evans, A.T. Influence of halothane, isoflurane, and sevoflurane on gastroesophageal reflux during anesthesia in dogs. Am. J. Vet. Res. 2006, 67, 1821–1825.
  23. Maclean, A.R.; Renwick, C. Audit of pre-operative starvation. Anaesthesia 1993, 48, 164–166.
  24. Pearse, R.; Rajakulendran, Y. Pre-operative fasting and administration of regular medications in adult patients presenting for elective surgery. Has the new evidence changed practice? Eur. J. Anaesthesiol. 1999, 16, 565–568.
  25. Crenshaw, J.T.; Winslow, E.H. Preoperative fasting: Old habits die hard. Am. J. Nurs. 2002, 102, 36–44.
  26. Warner, M.A.; Caplan, R.A.; Epstein, B.S.; Gibbs, C.P.; Keller, C.E.; Leak, J.A.; Maltby, R.; Nickinovich, D.G.; Schreiner, M.S.; Weinlander, C.M. Practice Guidelines for Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration: Application to Healthy Patients Undergoing Elective Procedures. Anesthesiology 2017, 126, 376–393.
  27. Engelhardt, T.; Webster, N.R. Pulmonary aspiration of gastric contents in anaesthesia. Br. J. Anaesth. 1999, 83, 453–460.
  28. Candian Anaesthetist’s Society The shortened fluid fast and the Canadian Anaesthetists’ Society’s new guidelines for fasting in elective/ emergency patients. Candian J. Anaesth. 1990, 37, 905–906.
  29. Brady, M.C.; Kinn, S.; Stuart, P.; Ness, V. Preoperative fasting for adults to prevent perioperative complications. Cochrane Database Syst. Rev. 2003, 1–126.
  30. Brady, M.; Kinn, S.; O’Rourke, K.; Randhawa, N.; Stuart, P. Preoperative fasting for preventing perioperative complications in children. Cochrane Database Syst. Rev. 2009, 7, 1–134.
  31. Miller, M.; Wishart, H.Y.; Nimmo, W.S. Gastric contents at induction of anaesthesia: Is a 4-hour fast necessary? Br. J. Anaesth. 1983, 55, 1185–1188.
  32. Lewis, M.; Crawford, J.S. Can one risk fasting the obstetric patient for less than 4 hours? Br. J. Anaesth. 1987, 59, 312–314.
  33. Agarwal, A.; ChariI, P.; Singh, H. Fluid deprivation before operation: The effect of a small drink. Anaesthesia 1989, 44, 632–634.
  34. Crawford, M.; Lerman, J.; Christensen, S.; Farrow-Gillespie, A. Effects of duration of fasting on gastric fluid pH and volume in healthy children. Anesth. Analg. 1990, 71, 400–403.
  35. Phillips, R.J.; Powley, T.L. Gastric content volume inhibits rather than food intake nutrient. Am. J. Physiol. 1996, 271, 766–769.
  36. Soreide, E.; Hausken, T.; Soreide, J.A.; Steen, P.A. Gastric emptying of a light hospital breakfast: A study using real time ultrasonography. Acta Anaesthesiol. Scand. 1996, 40, 549–553.
  37. Hardy, J.F.; Lepage, Y.; Bonneville-Chouinard, N. Occurrence of gastroesophageal reflux on induction of anaesthesia does not correlate with the volume of gastric contents. Can. J. Anaesth. 1990, 37, 502–508.
  38. Mcgrady, E.M.; Macdonald, A.G. Effect of the preoperative administration of water on gastric volume and ph. Br. J. Anaesth. 1988, 60, 803–805.
  39. Lotti, F.; Twedt, D.; Warrit, K.; Bryan, S.; Vaca, C.; Krause, L.; Fukushima, K.; Boscan, P. Effect of two different pre-anaesthetic omeprazole protocols on gastroesophageal reflux incidence and pH in dogs. J. Small Anim. Pract. 2021, 62, 677–682.
  40. Zacuto, A.C.; Marks, S.L.; Osborn, J.; Douthitt, K.L.; Hollingshead, K.L.; Hayashi, K.; Kapatkin, A.S.; Pypendop, B.H.; Belafsky, P.C. The Influence of Esomeprazole and Cisapride on Gastroesophageal Reflux During Anesthesia in Dogs. J. Vet. Intern. Med. 2012, 26, 518–525.
  41. Johnson, R.A. Maropitant prevented vomiting but not gastroesophageal reflux in anesthetized dogs premedicated with acepromazine-hydromorphone. Vet. Anaesth. Analg. 2014, 41, 406–410.
  42. Raptopoulos, D.; Galatos, A.D. Gastro-oesophageal reflux during anaesthesia induced with either thiopentone or propofol in the dog. Vet. Anaesth. Analg. 1997, 24, 20–22.
  43. Wilson, D.V.; Evans, A.T.; Mauer, W.A. Influence of metoclopramide on gastroesophageal reflux in anesthetized dogs. Am. J. Vet. Res. 2006, 67, 26–31.
  44. Garcia, R.S.; Belafsky, P.C.; Della Maggiore, A.; Osborn, J.M.; Pypendop, B.H.; Pierce, T.; Walker, V.J.; Fulton, A.; Marks, S.L. Prevalence of Gastroesophageal Reflux in Cats during Anesthesia and Effect of Omeprazole on Gastric pH. J. Vet. Intern. Med. 2017, 31, 734–742.
  45. Tsompanidou, P.; Robben, J.H.; Savvas, I.; Anagnostou, T.; Prassinos, N.N.; Kazakos, G.M. The Effect of the Preoperative Fasting Regimen on the Incidence of Gastro-Oesophageal Reflux in 90 Dogs. Animals 2022, 12, 64.
More
© Text is available under the terms and conditions of the Creative Commons Attribution (CC BY) license; additional terms may apply. By using this site, you agree to the Terms and Conditions and Privacy Policy.
This entry is offline, you can click here to edit this entry!
ScholarVision Creations
Feedback