A series of 10 cases of acid aspiration syndrome obtained from a study of the records of the anaesthetic Unit, Singapore General Hospital between 1962-1968 is described. Seven of these cases occurred in obstetric procedures and the remaining three were general surgicalprocedures. Eight of the ten cases died.
Restriction of oral food intake is a generally accepted step in the preoperative preparation of all surgical patients. Nevertheless, during anesthesia of patients, often pulmonary aspiration from regurgitated stomach contents occurred. This clinical study was done to determine stomach content: which might be present in the stomach despite an order that all food and fluid be withheld from the patients. Forty-five adult patients, twentynine children and thirty-four emergency obstetrical patients were suctioned at appropriate time andthe volume measured. Findings indicate that considerable volume of stomach contents is to be expected in even the best prepared cases. It is suggested that acid aspiration syndrome might be occurred in all the anesthetic patients including even the best prepared cases.
Aspiration of gastric contents occurring during general anesthesia is still a very serious complication. This syndrome entity resembles bronchial asthma. Bronchospasm, tachycardia, andpulmonary edema are the characteristic findings but the history, radiological and autopsy findings are quite unlike those of bronchial asthma. In most of cases, deaths which occurred rapidly was due to cardiovascular collapse.
Acid aspiration syndrome occurred in some cases where there was no history of vomiting or regurgitation. Among those cases where vomiting or regurgitation preceded aspiration it is noted that regurgitation is more liable to be followed by aspiration than vomiting.
The onset of symtoms from the time of regurgitation or vomiting varied from 30 minutes to 3 hours. This syndrome is more commonly seen in obstetric procedures than in other types of patients.
The use of intermittent positive pressure ventilation in cases of this Syndrome has been found to have no effect on the pulmonary edema. However, no explanation can be offered for this observation.
Among the cases which survived, there was rapid radiological clearing of the lung fields usually one week from the onset.
It is suggested that in obstetric patients in whom an unexplained tachycardia or mild bronchial wheezing is noted following recovery from general anesthe use of bronchial lavage and steroid may be of value in preventing the development ofa full -blown acid aspiration syndrome.
In conclusion it is clear that there are at present no methods available which will prevent aspiration occurring or after anesthesia. The only factor which significantly reduces the incidence of this condition is the more close care of the anesthetists.
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