thiopental and Pneumonia--Aspiration

All patients undergoing general anaesthetic are at risk of acid aspiration, particularly in emergency situations when they have not been starved preoperatively. To minimise the risk of acid aspiration, anaesthetists and anaesthetic nurses employ Rapid Sequence Induction of anaesthesia, cricoid pressure and endotracheal intubation. Knowledge of airway anatomy, airway management techniques, anaesthetic agents, muscle relaxant drugs, and Sellick's Manoeuvre help the anaesthetic nurse ensure the safety of the high risk patient.

Topics: Anesthesia, General; Anesthetics, Intravenous; Atracurium; Etomidate; Humans; Neuromuscular Agents; Nurse Anesthetists; Nurse's Role; Pneumonia, Aspiration; Propofol; Risk Factors; Safety Management; Succinylcholine; Thiopental

Topics: Abortion, Septic; Adult; Anesthesia, General; Anesthesia, Local; Anesthesia, Obstetrical; Anesthesiology; Anesthetics, Local; Apgar Score; Cesarean Section; Cyclopropanes; Ether; Female; Humans; Infant, Newborn; Ketamine; Maternal-Fetal Exchange; Monitoring, Physiologic; Nitrous Oxide; Obstetric Labor Complications; Pneumonia, Aspiration; Pregnancy; Shock, Septic; Succinylcholine; Thiopental

In cases of aspiration of gastric contents the risk of pneumonitis is dependent on the pH and volume of the gastric contents. Omeprazole and rantidine each decrease gastric volume and increase gastric pH. We evaluated the efficacy of preoperative administration of omeprazole (60 mg) or ranitidine (150 mg) in the prophylaxis of aspiration pneumonitis.. Data were obtained from 75 elective female surgical patients randomly allocated to one of three groups, who received either omeprazole 60 mg orally, or ranitidine 150 mg orally, or neither, on the evening prior to, and on the morning of, surgery. Gastric volume and pH was measured using blind aspiration.. Both pH < 2.5 and volume > 25 mL were present in none of the patients in either the ranitidine or omeprazole groups, compared to 15 of 25 control patients (P < 0.0001).. Preoperative oral administration of omeprazole (60 mg) or ranitidine (150 mg) reduced residual gastric content volume and increased pH > 2.5, possibly reducing the effects of pulmonary aspiration of gastric contents.

Topics: Administration, Oral; Adult; Anesthetics, Inhalation; Anesthetics, Intravenous; Anti-Ulcer Agents; Elective Surgical Procedures; Female; Gastrointestinal Contents; Humans; Hydrogen-Ion Concentration; Intubation, Gastrointestinal; Isoflurane; Middle Aged; Nitrous Oxide; Omeprazole; Pneumonia, Aspiration; Premedication; Ranitidine; Statistics, Nonparametric; Thiopental

A questionnaire survey examining rapid sequence induction techniques was sent to all anaesthetists in Wales. The questionnaire presented five common clinical scenarios: emergency appendicectomy; elective knee arthroscopy with a symptomatic hiatus hernia; elective knee arthroscopy with an asymptomatic hiatus hernia; elective Caesarean section; and emergency laparotomy for bowel obstruction. Completed surveys were received from 421 anaesthetists, a 68% response rate. Rapid sequence induction was chosen by 398/400 respondents (100%) for bowel obstruction, 392/399 (98%) for Caesarean section, 388/408 (95%) for appendicectomy, 328/395 (83%) for symptomatic hiatus hernia but only 98/399 (25%) for asymptomatic hiatus hernia (p < 0.001). Trainees were more likely to use a rapid sequence induction technique than consultants and staff grades for the appendicectomy (p = 0.025), symptomatic hiatus hernia (p = 0.004) and asymptomatic hiatus hernia (p = 0.001) scenarios and were also more likely to use a thiopental-suxamethonium combination for rapid sequence induction (p < 0.001).

Topics: Adult; Aged, 80 and over; Anesthesia, General; Anesthesia, Obstetrical; Appendectomy; Cesarean Section; Emergencies; Female; Health Care Surveys; Hernia, Hiatal; Humans; Hypnotics and Sedatives; Intestinal Obstruction; Intubation, Intratracheal; Male; Neuromuscular Blockade; Pneumonia, Aspiration; Pregnancy; Professional Practice; Thiopental; Wales

Topics: Adult; Anesthesia, Inhalation; Anesthesia, Obstetrical; Cesarean Section; Emergencies; Female; Fetal Distress; Humans; Infant, Newborn; Pneumonia, Aspiration; Postoperative Complications; Pregnancy; Risk Factors; Thiopental

In an attempt to explain the discrepancy between the high number of patients said to be at risk of aspiration pneumonitis and the low reported incidence of this anaesthetic complication, 100 ASA physical status I-II elective surgical patients were studied. The volume of fluid present in the stomach at the time of induction of anaesthesia was correlated with gastroesophageal reflux (GER) detected by visual inspection of the pharynx and by continuous measurement of upper oesophageal pH. Mean gastric volume was 30 +/- 28 ml (range 0-210 ml). Gastric fluid volume greater than or equal to 0.4 ml.kg-1 at pH less than or equal to 2.5 was present in 46 patients. No GER was detected during induction of anaesthesia in our sample of 100 patients. Furthermore, patient age, duration of preoperative fasting, body mass index, cigarette smoking, alcohol consumption, preoperative anxiety, and a history of preoperative GER were not correlated with significant modifications of gastric volume or pH. We conclude that the low incidence of aspiration pneumonitis in elective surgical patients may be explained in part by the very low risk of GER, despite gastric fluid volumes of more than 0.4 ml.kg-1 in a high proportion of this patient population.

Topics: Adult; Female; Gastroesophageal Reflux; Gastrointestinal Contents; Humans; Male; Middle Aged; Pneumonia, Aspiration; Risk Factors; Thiopental

Twenty-five non-smokers and 35 smokers who had abstained overnight from cigarette smoking and were undergoing minor elective orthopaedic surgery were studied in order to compare gastric volume and pH. There was no significant difference in aspirated volume and pH both just after intubation and prior to extubation between the two groups, thus indicating that habitual smokers undergoing elective surgery in general anaesthesia do not have increased risk of acid pulmonary aspiration compared with non-smokers.

Topics: Adolescent; Adult; Aged; Anesthesia, General; Female; Gastric Acidity Determination; Gastric Juice; Halothane; Humans; Male; Middle Aged; Nitrous Oxide; Orthopedics; Pneumonia, Aspiration; Risk; Smoking; Thiopental

Topics: Anesthesia; Anesthesia, Inhalation; Burns; Diazepam; Enflurane; Fentanyl; Halothane; Humans; Intubation, Intratracheal; Isoflurane; Ketamine; Monitoring, Physiologic; Neuromuscular Nondepolarizing Agents; Nitrous Oxide; Pneumonia, Aspiration; Succinylcholine; Thiopental

In a double-blind study, 107 patients undergoing elective and emergency surgical procedures were given 15 ml of either sodium citrate 0.3 M or placebo 10 minutes before induction of anaesthesia. Gastric contents were sampled immediately after induction and the pH was measured. The mean pH of the Gastric contents of patients given sodium citrate was 5.67, whereas for those given the placebo it was 3.21 (p less than 0.001). Of patients given sodium citrate 92% had a gastric pH above 3.0 compared with only 37% in the placebo group (p less than 0.001). At the end of surgery gastric contents were emptied as completely as possible and the volume and pH measured. There was no significant difference in the mean volume of gastric contents in the two groups. In neither group was the mean pH at the end of surgery significantly different from that after induction.

Topics: Adolescent; Adult; Aged; Anesthesia, General; Antacids; Citrates; Citric Acid; Double-Blind Method; Female; Gastric Acidity Determination; Humans; Male; Middle Aged; Placebos; Pneumonia, Aspiration; Postoperative Complications; Preanesthetic Medication; Thiopental

Hydrochloric acid was instilled into the bronchial tree in anaesthetized dogs. A severe respiratory acidosis resulted. The metabolic component of acid-base balance was little affected.

Topics: Acidosis, Respiratory; Anesthesia, General; Animals; Carbon Dioxide; Disease Models, Animal; Dogs; Female; Halothane; Hematocrit; Hydrochloric Acid; Hydrogen-Ion Concentration; Lung; Male; Nitrous Oxide; Organ Size; Oxygen; Pneumonia, Aspiration; Respiration; Thiopental

Topics: Anesthesia, General; Anesthesia, Obstetrical; Antacids; Cesarean Section; Cognition; Female; Humans; Infant, Newborn; Infant, Newborn, Diseases; Inhalation; Intubation, Gastrointestinal; Intubation, Intratracheal; Laryngeal Edema; Nitrous Oxide; Pneumonia, Aspiration; Posture; Pregnancy; Pregnancy Complications, Cardiovascular; Succinylcholine; Syndrome; Thiopental; Time Factors; Vascular Diseases; Vena Cava, Inferior