Effect of Cigarette Smoking in Non-Per os Period on Gastric Fluid Volume and pH
Background: We investigated the effects of cigarette smoking in non-per os (NPO) period on volume and pH of gastric contents in smoker male patients.
Methods: In a prospective cohort study, 86 male smoker patients undergoing elective non-abdominal surgery under general anesthesia, were surveyed. They were NPO for at least 8-12 hrs. prior to surgery without direction to smoking. Then they were divided in two groups in the operation room based on smoking during NPO period. The study was continued until 43 patients entered in each group. After induction of anesthesia, gastric contents were aspirated by NG tube then volume and pH of gastric contents were measured. There were no significant differences in basic characteristics of patients such as age and weight between two groups.
Results: The pH of gastric content was significantly lower in the smokers group (1.57±0.74 vs 3.12±1.90 p=0.001). The mean volume was significantly higher in the smokers’ group (34.60±20.90 vs 19.86±14.72 ml, p=0.001).
Conclusion: Smoking during NPO period in habitual smokers before elective surgery increases the volume and acidity of gastric contents and probably increases risk of acid pulmonary aspiration.
Adelhøj B, Petring OU, Jensen BN, Mikkelsen S. Refraining from cigarette smoking before premedication does not decrease the risk of acid pulmonary aspiration during anaesthesia. Can Anaesth Soc J. 1985; 32(5): 499-501.
Rodrigo C. The effects of cigarette smoking on anesthesia. Anesth Prog. 2000; 47(4): 143-150.
Zwissler B, Reither A. Preoperative abstinence from smoking. An outdated dogma in anaesthesia? Anaesthesist. 2005; 54(6): 550-9.
Beckers S, Camu F. The anesthetic risk of tobacco smoking. Acta Anaesthesiol Belg. 1991; 42(1): 45-56.
Brady M, Kinn S, Stuart P. Preoperative fasting for adults to prevent preoperative complications. Cochrane Database Syst. Rev. 2003; (4): CD004423.
Mendelson CL. The aspiration of stomach contents into the lungs during obstetric anaesthesia. Am J Obstet Gynecol. 1946; 52:191-205.
Roberts RB, Shirley MA. Reducing the risk of acid aspiration during cesarean section. Anesth. Analg. 1974; 53(6): 859-68.
Vaughan RW, Bauer S, Wise L. Volume and pH of gastric juice in obese patients. Anesthesiology. 1975; 43(6): 686-9.
Søreide E, Holst-Larsen H, Veel T, Steen PA. The effects of chewing gum on gastric content prior to induction of general anesthesia. Anesth Analg. 1995; 80(5): 985-9.
Hardy JF, 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(5): 502-8.
Moore MW, Meyer RM. Elective ambulatory surgery: must the patient be NPO? JAMA. 1990; 263: 733.
Dubin SA, Jense HG, McCranie JM, Zubar V. Sugarless gum chewing before surgery does not increase gastric fluid volume or acidity. Can J Anaesth. 1994; 41(7): 603-6.
Wright DJ, Pandya A. Smoking and gastric juice volume in outpatients. Can Anaesth Soc J. 1979; 26(4): 328-30.
Adelhøj B, Petring OU, Frøsig F, Bigler DR, Jensen BN. Influence of cigarette smoking on the risk of acid pulmonary aspiration. Acta Anaesthesiol Scand. 1987; 31(1): 7-9.