The Clinical Investigation of Gastric Volume and pH Under General Anesthesia / 대한마취과학회지

In recent years, there has been renewed interest in preoperative methods to reduce gastric acidity, thus lessening the risk of a serious pulmonary reactions following aspiration of gastric contents. Emergency obstetrical patients frequently have large volumes of gastric fluid. It is less commonly appreciated that patients fasting prior to elective surgery afterive in operating room with large gastric fluid volumes with a low pH. Prophylactic preoperative oral administration of antacids has been shown to reduce preoperative gastric acidity in significant percentage of patients, but aspiration of antacids can be associated with pulmonary complications, and there use may be associated with increased gastric volume. Preoperative adrpinistration of glycopyrrolate may decrease the frequency of surgical patients with a low gastric pH, and it appears that the volume of gastric fluid may be reduced by medication that relax the pylorus. However, none of these pharmacologic manuevers completely abolisbes the possibility of serious pulmonary damage with aspiration. Mendelson and Teabeat demonstrated the importance of pH in the etiology of acid aspiration and it is generally accepted that the critical pH is 2. 5 or less, i.e. the risk of aerious pulmonary reaction increases progressively as the pH of the aspirate falls below 2.5. A critical volume of acid aspirate is also necessary for widespread pulmonary damage to occur irrespective of a low gastric pH. The critical volume is rhesus monkeys has been shown to be 0.4 ml/kg, but the critical volume in man is less well difined. Several investigators have determined the patient to be at risk of serious pulmonary complications with aspiration if at least 25 ml of gastric fluid with a pH of 2.5 or less is aspirated. The present study was undertaken to investigate the effects on the volume and pH of gastric juice under general anesthesia. The 35 patients were studied, and were divided. into 4 group account to the kind of premedicants, N.P.O. time, weight, and obstetric patients Gastric juice, aspirated through a Levine tube, was examined for pH and. volume under general anesthesia.

The Observation of Complications after General Anesthesia / 대한마취과학회지

Recently, with the remarkable theoretical progress made in anesthesiology these years, reports are being made on the results of the study on the complications, minor or major, caused by previous general anesthesia. However, .the reports on incidence vary according to the reporters. According to Riding, the recent development of anesthesiology, anesthetic inatruments, knowledge of physiology, anesthetics, induction agents and muscle relaxants are said to have reduced the incidence of complications to a great extent. Riding, Gold and Dyrberg report that the factors capable of influencing the incidence of complication, in the post-operative period include age, sex, premedicants for anesthetics, inhalation method of anesthetics, time of anesthesia, muscle relaxant, use of induction agent, acid-base imbalance and developed knowledge of physioloy, operation site, mental state of patients before operation, general condition, anesthetic technique, and. adequate selection of medicine. Working for Department of Anesthesiology, Hanyang University, from October 1976 to August 1977, we selected, out of the patients who received general anesthesia, 523 males and 372 females, totalling 895, who showed no abnormal symptoms in their respiratory systems, circulatory systems and metabolic systems and observed the incidence of complication in the light of sex, age and operation site, the factors supposed to affect the incidence. An hour prior to the general anesthesia, the patients were given intramuscular injection with premedicants atropine 0. 01 mg per kg, Valium 0. 2 mg or Demerol 1 mg per kg of body weight. For induction of anesthesia, Epontol 10 mg per kg and succinylcholine 1 mg per kg of body weight were injected in the veins, then ventilation was made for a minute with mask and then endotracheal tubes were inserted. and then a minimum amount of air was injected. into the cuff of the endotracheal tube, and the ventilation was done in a semi-closed system. During the period of maintenance, anesthesia was administered in a semi-closed system with 0. 5~l. 0% halothane, 3 L/min of nitrous oxide, 2 L/min of oxygen; and if need be, muscle relaxant was injected into the vein. In case a nondenolarizing agent was used in the course of maintenance, atropine 0. 5~1. 0 mg and neostigmine 2.0 ~ 4.0 mg were injected into the vein for reversion at the recovery time. After the patient was completely recovered, the endotracheal tube was cautiously removed, so as not to give trauma to the throat. As for method of observations, 24 hours after the patient had recovered, we visited the patient in the ward, first observing the existence or nonexistence of incidence of minor complications, and then calculating the incidence by the distribution of sex, age and operation site. The outcome of the observation of the above results by statistics and by chi square test is as follows; 1) the incidence of complications after general anesthesia was high in females. 2) Age has not affected the incidence of complications. 3) The incidence of nausea was highest in the patients with abdominal operation. 4) The incidence of sore throat was highest in the head and neck patients. 5) The incidence of fever was highest in the abdomen patients. 6) The incidence of headache was highest in the head and neck patients.