Effect of endogenous progesterone and oestradiol-17beta on the incidence of gastro-oesophageal reflux and on the barrier pressure during general anaesthesia in the female dog.
OBJECTIVE
To investigate the potential effect of increased blood progesterone (P(4)) and oestradiol-17beta (E(2)) concentrations on the barrier pressure (BrP) and the incidence of gastro-oesophageal reflux (GOR) in female dogs under general anaesthesia.


METHODS
Prospective, blinded experimental trial.


METHODS
Seven female, adult, healthy dogs weighing 14-21 kg and aged 1-7 years.


METHODS
Each of the animals was studied under the influence of high blood E(2) and basal P(4) (study O), basal E(2) and high P(4) (study P) and basal E(2) and P(4) (study C) concentrations. Animals were premedicated with acepromazine and anaesthesia was induced with thiopental and maintained with halothane. Lower oesophageal pH was monitored continuously for 1 hour after induction. GOR was defined as oesophageal pH >7.5 or <4. Manometry of the posterior oesophageal sphincter (POS) was then performed using the slow pull-through technique.


RESULTS
Acid GOR was detected in only one animal of study O. The three studies did not differ significantly in GOR. Mean BrP was 11.2 (study O), 9.1 (study P) and 11.6 mmHg (study C). No significant differences were detected with respect to mean BrP, intra-gastric pressure and POS pressure.


CONCLUSIONS
It is unlikely that the increased concentrations of E(2) or P(4) during the normal ovarian cycle influence the functional efficiency of the POS as a major barrier to GOR in healthy, female dogs under general anaesthesia.


CONCLUSIONS
The fact that female dogs undergoing obstetrical surgery represented a substantial sub-group of the animals which developed postoperative benign oesophageal stricture, should probably not be attributed to the effects of increased concentrations of female sex steroid hormones.
Anagnostou
Tilemahos L
TL
Anaesthesia and Intensive Care Unit, Department of Clinical Sciences, Faculty of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece. tanagnos@vet.auth.gr
Savvas
Ioannis
I
Kazakos
George M
GM
Ververidis
Haralabos N
HN
Haritopoulou
Maria-Rea
MR
Rallis
Timoleon S
TS
Raptopoulos
Dimitris
D
D000768:Anesthesia, General / Q000009:adverse effects / Q000662:veterinary*; D000818:Animals; D004283:Dog Diseases / Q000139:chemically induced*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004943:Esophagogastric Junction / Q000187:drug effects*; D004958:Estradiol / Q000097:blood*; D030762:Estrous Cycle / Q000097:blood / Q000502:physiology; D005260:Female; D005764:Gastroesophageal Reflux / Q000139:chemically induced*; D011312:Pressure; D011374:Progesterone / Q000097:blood*; D013874:Thiopental / Q000008:administration & dosage / Q000494:pharmacology
D011374:Progesterone; D004958:Estradiol; D013874:Thiopental