Acid Aspiration Prophylaxis Research Articles

Comparison of ultrasonographic measurement of gastric antral volume and pH with or without pharmacological acid aspiration prophylaxis in low-risk surgical patients - A randomized clinical trial.

The role of preoperative pharmacological prophylaxis in preventing aspiration pneumonitis under general anesthesia (GA) in patients at low risk of aspiration pneumonitis is still under debate. We addressed the need for routine pharmacological aspiration prophylaxis in at-risk population by assessing the change in gastric volume using ultrasound with and without pharmacological acid aspiration prophylaxis. A single-center, randomized double-blinded trial, with 200 adult patients scheduled for elective surgical procedures under GA, were randomized into a prophylaxis group, in which the patients received oral famotidine and metoclopramide, and a no prophylaxis group, in which the patients did not receive any prophylaxis. Gastric volume derived from preinduction measurement of gastric antral volume by ultrasound, postinduction gastric pH, and incidences of aspiration pneumonitis were compared. Bland-Altman plot was used to determine the level of agreement between measured gastric volume and ultrasonography based on calculated gastric volume. The gastric antral cross-sectional area (CSA) and volume in the no prophylaxis group (3.12 cm2 and 20.11 ml, respectively) were comparable to the prophylaxis group (2.56 cm2 and 19.67 ml, respectively) (P-values 0.97 and 0.63, respectively). Although there was a statistically significant decrease in gastric pH in the no prophylaxis group (P-value 0.01), it was not clinically significant to increase the risk of aspiration pneumonitis based on Roberts and Shirley criteria (P-value 0.39). In an adequately fasted low-risk population, the amount of residual gastric volume was similar and below the aspiration threshold, regardless of the aspiration prophylaxis status.

Anaesthesia for Caesarean section and acid aspiration prophylaxis

Anaesthesia for Caesarean section and acid aspiration prophylaxis

Acid aspiration prophylaxis in labour: a survey of UK obstetric units

The risk of acid aspiration is still a major concern in pregnant patients. In view of the increasing numbers of drugs available to decrease gastric acid production, it seemed timely to reassess acid aspiration prophylaxis policies in the UK. An OAA-approved postal survey of 250 UK lead consultant obstetric anaesthetists was conducted in 2004 in order to establish the current practice of acid aspiration prophylaxis in labour. If acid aspiration prophylaxis was used, further questions were asked relating to subgroups of patients, category, dose and route of administration of drugs used and whether there was an anticipated change in practice. A response rate of 83% was achieved. There had been a decrease in the routine use of acid aspiration prophylaxis to 32% of units, an increase in the use of acid aspiration prophylaxis in "at risk" groups to 61% and a decrease in the number of units never using prophylaxis to 7%. Oral ranitidine administered six-hourly is the most common practice. There is little use of proton pump inhibitors. Compared to previous surveys of UK practice there has been an overall increase in the use of acid aspiration prophylaxis.

Acid aspiration prophylaxis in obstetrics in France: a comparative survey of 1998 vs. 1988 French practice

Background and objective: To survey French anaesthetic practice regarding acid aspiration prophylaxis and compare it with an earlier survey. Methods: A confidential questionnaire was sent to all 800 maternity units in France to assess three major topics: (a) drugs used for pharmacological prophylaxis; (b) regional anaesthesia for labour and Caesarean section and (c) techniques used for general anaesthesia and endotracheal intubation. Results: Two-hundred-and-two units responded. Pharmacological prophylaxis was regularly used for labouring women in 78% of the responding units in 1998 (compared with 63% in 1988, P < 0.05). Antacid drug use before Caesarean section had increased from 75% in 1988 to 97% in 1998 (P < 0.05). General anaesthesia was used for Caesarean section by less than 2% of responding units (vs. 21% in 1988, P < 0.05). In contrast, there was little change in the use of endotracheal intubation for instrumental delivery (53% vs. 50%) or manual removal of the placenta (15% vs. 16%) between 1988 and 1998. The use of cricoid pressure increased significantly during the 10 yr period (50% vs. 88%, P < 0.05) and the technique was correctly described by 80% of the responding units (vs. 50%, P < 0.05). Similarly, the use of succinylcholine increased significantly from 25% (1988) to 47% (1998) (P < 0.05). Conclusions: There was a significant overall improvement of French practice regarding acid aspiration prophylaxis in obstetrics. However, the complete prophylaxis strategy is still not used in every patient emphasizing the need for continuing medical education.

Aspiration and regurgitation prophylaxis in paediatric anaesthesia.

Surveys of aspiration prophylaxis in paediatric anaesthesia do not exist. A postal survey was sent out to all UK members of the Association of Paediatric Anaesthetists (APA) to assess current practice. We asked about minimum fasting times for liquids and solids/milk, their routine acid aspiration prophylaxis and perceived risk factors for emergency and elective surgery in children those less than 1 year old and those aged 1-14 years. We also asked if the APA member had more than 10 years experience in paediatric anaesthesia. One hundred and two (55.1%) APA members replied out of a total of 185 questionnaires sent. Eighty-eight (88/102) were considered valid. Fasting in emergencies is approximately 4 h for solids/milk and 2 h for clear liquids. Fasting for elective surgery is between 5 and 6 h for solids/milk and 2 h for clear liquids. Pharmacological methods to reduce the risk of aspiration are not used. Mechanical methods vary from 40-50% for cricoid pressure and 20-30% for nasogastric aspiration if a tube is present. The presence of a hiatus hernia is perceived by over 80% as a risk factor, previous aspiration by over 60%, difficult intubation, cerebral palsy and sepsis by 20-30%. Perceived risk factors vary with "experience": hiatus hernia, difficult intubation and cerebral palsy are less important whereas previous aspiration and renal failure appear to be more important for paediatric anaesthetists with less than 10 years in paediatric anaesthetic practice.

Anesthesia for Cesarean Section and Acid Aspiration Prophylaxis: A German Survey

Anesthesia for Cesarean Section and Acid Aspiration Prophylaxis: A German Survey

Anesthesia for Cesarean Section and Acid Aspiration Prophylaxis

Anesthesia for Cesarean Section and Acid Aspiration Prophylaxis

Anesthesia for Cesarean Section and Acid Aspiration Prophylaxis

Anesthesia for Cesarean Section and Acid Aspiration Prophylaxis

Anesthesia for Cesarean Section and Acid Aspiration Prophylaxis

In Response: We greatly appreciate the interest of Dr. Goudsouzian, who was among the first investigators to recommend H2 blockers in pediatric anesthesia. Concerning the first paragraph of his letter, however, he obviously misread our summary, which states, "more widespread use in obstetric anesthesia and [instead of than] in other patients at risk." Moreover, we clearly stated that the number of more than one fatality per year relies on death from acid aspiration in Germany in the context of cesarean section only. We have no data allowing even for a guess on fatalities in other surgical fields. With an incidence of acid aspiration of approximately 1:1500-3000 and a mortality as low as 5%, no ethically conducted study will ever prove the benefit of prophylactic measures in humans, be it drugs, positioning, esophageal compression, or even nil per os. We are as uncomfortable as Dr. Goudsouzian seems to be with what is generally called critical gastric volume or critical acidity, because both have been arbitrarily set after a single, not too elaborate, experiment in one almost suffocated monkey [1]. A later well designed study in primates clearly showed that aspirating gastric juice of pH 1.0 was deleterious only if high volumes were administered [2]. In other species, however, acidity of the aspirate proved crucial for outcome [3,4]. We fully agree with Dr. Goudsouzian that there are no data to scientifically prove the benefit of any prophylactic measure to avoid acid aspiration or to alleviate its consequences once it occurs. However, with the data from animal studies and clinical observations in mind, we still believe that lowering gastric volume (e.g., by fasting), decreasing the probability of regurgitation (e.g., by positioning, cricoid pressure, or fast induction), and reducing the acidity of an occasionally aspirated aliquot is worth the small effort. We believe this even more because, in most circumstances, a sensible head-up position, an expertly performed Sellick's maneuver, newer H2 blockers, and sodium citrate are easily applied, without real side effects, and inexpensive. In the worst case, all recommended measures may be unnecessary. This, however, cannot be proven, either. Because all measures are not really harmful, we would prefer taking the risk of applying useless measures instead of missing a potential benefit. Hajo Schneck, MD Michaela Scheller, MD Eberhard Kochs, MD Institut fur Anaesthesiologie der Technischen; Universitat Munchen; Klinikum Rechts der Isar; 81675 Munchen, Germany

Anesthesia for Cesarean Section and Acid Aspiration Prophylaxis

Anesthesia for Cesarean Section and Acid Aspiration Prophylaxis

Anesthesia for cesarean section and acid aspiration prophylaxis: a German survey.

We surveyed routine anesthetic practice and measures to prevent acid aspiration syndrome (AAS) in patients undergoing cesarean section (CS) throughout Germany. Of 1061 questionnaires, 81.9% were returned. For scheduled CS, general anesthesia was used in 63% of cases, and for urgent CS, it was used in 82% of cases. Regional anesthesia was used less often for both scheduled and urgent CS in smaller (< or =500 deliveries/yr; 28% and 16%, respectively) than in medium-sized (500-1000 deliveries/yr; 42% and 19%, respectively) or major obstetric departments (>1000 deliveries/yr; 45% and 21%, respectively). Among the regional techniques, epidural anesthesia (59%) was preferred more than spinal anesthesia (40%) in scheduled CS. In urgent CS, spinal anesthesia predominated (56% vs 42%). Pharmacological AAS prophylaxis is routinely used in 69% (68%) of departments before elective (urgent) CS under general anesthesia and in 52% under regional anesthesia. H2-blocking drugs are preferred for AAS prophylaxis over H2-blocker plus sodium citrate and sodium citrate alone. Both the incidence of and the mortality from AAS at CS are very low in Germany (<1 fatality per year). Nevertheless, AAS prophylaxis deserves more widespread use in obstetric anesthesia and in other patients at risk (e.g., children, outpatients). According to a countrywide survey, the use of regional anesthesia for cesarean section and pharmacological prophylaxis of acid aspiration syndrome is considerably less common in Germany than in the United States, United Kingdom, or other European countries.

Anaesthesia for caesarean section--a German survey.

Anaesthetic practice for caesarean section has changed during the last decades. There is a world-wide shift in obstetric anaesthetic practice in favour of regional anaesthesia. Current data concerning anaesthetic practice in patients undergoing caesarean section from Germany are not available. A comparison with figures from the UK, USA, Norway and other European countries might be of general interest. Questionnaires on the practice of anaesthesia for caesarean section and anaesthetic coverage of the obstetric units were sent to 1178 university, tertiary care, district, community and private hospitals in Germany. The 532 completed replies of this survey represent 46.9% of the German obstetric units. Most hospitals (42.3%) have delivery rates between 500 and 1000 per year. General anaesthesia is the most common anaesthetic technique for elective (61%), urgent (83%) and emergency caesarean section (98%). Epidural anaesthesia is performed in 23% of scheduled and 5% of non-scheduled caesarean sections, and spinal anaesthesia in 14% and 10% respectively. Acid aspiration prophylaxis before elective caesarean section is used in 68.7% of the departments. The majority of the departments provide a 24-hour anaesthetic coverage; however, in only 6.2% of the units, this service is assigned to obstetric anaesthesia, exclusively. Compared to data from 1978, anaesthetic practice for caesarean section has changed with an increase in regional anaesthesia. However, German anaesthetists prefer general anaesthesia for caesarean section. In contrast, anaesthetists in other countries predominantly use regional techniques, and the difference to German practice is striking. International consensus discussion and recommendations as well as comparable European instruments of quality control in obstetric anaesthesia are desirable.

Acid aspiration prophylaxis for emergency Caesarean section

Over a 3.5 year period, 384 patients requiring emergency Caesarean section under general anaesthesia received at random one of six acid aspiration prophylaxis regimens as soon as the decision was made for surgery. In the first phase of the study, sodium citrate administered orally 0.3 M, 30 ml (group C, n = 120) was compared with metoclopramide 10 mg administered intravenously and sodium citrate (group MC, n = 65). In the second phase, all patients received sodium citrate, and either intravenous administration of ranitidine 50 mg (group RC, n = 50), omeprazole 40 mg (group OC, n = 50), ranitidine 50 mg with metoclopramide 10 mg (group RMC, n = 50) or omeprazole 40 mg with metoclopramide 10 mg (group OMC, n = 49). Gastric contents were aspirated using a 16 FG Salem sump tube and acidity measured with a pH meter. Non-parametric tests were used for comparisons. There was no difference in gastric volume or pH between groups C and MC, or among OC, RC, OMC and RMC. After pooling the data, median (range) gastric volume in groups C and MC (55 (0-360) ml) was greater than in groups OMC and RMC (40 (3-270) ml, p < 0.05). Median (range) pH was lower in groups C and MC (4.97 (0.76-6.99)) than in groups OC, RC, OMC and RMC (5.76 (1.11-7.5), p < 0.001). The proportion of patients with pH < 3.5 and volume > 25 ml in the C and MC groups (43/185) was greater than that in the OC, RC, OMC and RMC groups (18/199, p < 0.001). Ranitidine and omeprazole administered intravenously were equally effective adjuncts to sodium citrate in reducing gastric acidity for emergency Caesarean section. Compared with sodium citrate alone, the addition of either ranitidine, omeprazole or metoclopramide alone did not reduce gastric volume while small reductions in gastric volume were seen with the addition of metoclopramide and either ranitidine or omeprazole.

Acid aspiration prophylaxis in elective biliary surgery A comparison of omeprazole and famotidine using manually aided gastric aspiration

We have compared the effects of single oral doses of omeprazole 40 mg, famotidine 40 mg or placebo on gastric secretion in 45 non-obese patients the night before elective biliary surgery. After stable anaesthesia had been established, a Salem orogastric tube was introduced and gastric contents were aspirated by a blinded observer. The volume and pH were noted. After the abdomen was opened aspiration was repeated but on this occasion with the surgeon's manual assistance. We found that the initial aspirate volume underestimated total gastric volume by an average (SD) of 7.1 (6.6) ml. Famotidine, but not omeprazole, produced a significant decrease in gastric volume and acidity. Patients were considered to be at risk if pH < 2.5 and volume > 0.4 ml.kg-1. Three patients in the omeprazole group, three in the placebo group and none in the famotidine group came into this category. We conclude that a single oral dose of omeprazole 40 mg given the night before surgery does not afford adequate prophylaxis for acid aspiration syndrome.

Acid aspiration prophylaxis in 202 obstetric anaesthetic units in the UK

A postal survey of obstetric anaesthetic units in the UK was conducted by questionnaire to gain information about current acid aspiration prophylaxis. Information regarding the delivery rate and the caesarean section rate under regional techniques was also requested. Replies were received from 202 obstetric anaesthetic units in the UK, a 75% response rate. The results are compared to similar surveys carried out in 1984 and 1988. Sodium citrate and the H 2 antagonist ranitidine remain the drugs most commonly used for acid aspiration prophylaxis. However, the number of departments carrying out routine prophylaxis for patients in active labour has fallen from 75% in 1988 to 57% in the current survey.

Perioperative pulmonary aspiration in children: a review

SummaryThe incidence of significant pulmonary aspiration in children is very low. Factors determining risk include the anaesthetist's experience, the child's ASA status, gastro‐oesophageal disease, obesity, intra‐abdominal obstruction, emergencies, trauma and the occurrence of laryngospasm. The diagnosis of pulmonary aspiration may be confused with post‐obstructive pulmonary oedema. Several approaches to risk reduction can be used and include appropriate pre‐operative fasting, acid aspiration prophylaxis and anaesthetic management. The widespread use of acid aspiration prophylaxis cannot be justified. Less emphasis should be placed on the ‘cut‐off’ values for gastric fluid contents of pH 2.5 and volume 0.4 ml·kg−1 in defining aspiration risk. Clear fluid fasts beyond 2–3 h do not result in reduced gastric fluid volume and if prolonged can be potentially harmful. It seems appropriate to use this interval in fasting guidelines for clear fluids. Recommended guidelines for solids vary from 4 h to no solids on the day of surgery.

Does 360 ml of Apple Juice Ingested Before Elective Surgery Worsen Gastric Volume and Acidity in Patients Given Acid Aspiration Prophylaxis?

Does 360 ml of Apple Juice Ingested Before Elective Surgery Worsen Gastric Volume and Acidity in Patients Given Acid Aspiration Prophylaxis?

Evaluation of omeprazole for acid aspiration prophylaxis in cardiac surgery

Evaluation of omeprazole for acid aspiration prophylaxis in cardiac surgery

Does 360 ml of apple juice ingested before elective surgery worsen gastric volume and acidity in patients given acid aspiration prophylaxis?

Does 360 ml of apple juice ingested before elective surgery worsen gastric volume and acidity in patients given acid aspiration prophylaxis?

Does 360 ml of apple juice ingested before elective surgery worsen gastric volume and acidity in patients given acid aspiration prophylaxis?

Study Objective: To evaluate whether 360 ml of oral clear liquids consumed within 4 hours of elective surgery worsens gastric volume and acidity in patients given acid aspiration prophylaxis. Design: Randomized, unblinded study. Setting: Main operating room at a U.S. military hospital. Patients: Eighty-three adult inpatients scheduled to receive general anesthesia for elective surgery. Interventions: Nineteen patients (Group 1) were given 150 mg of oral ranitidine (two doses), 10 mg of metoclopramide, and 360 ml of apple juice 3 hours before the scheduled start of surgery. Thirty-four patients (Group 2) fasted before surgery but received acid aspiration prophylaxis identical to that given to Group 1. Twenty-three additional patients (Group 3) received no oral fluids or acid aspiration prophylaxis before surgery. Measuremnts and Main Results: The residual gastric volume (RGV) and the pH of Group 1 patients were compared with measurements obtained in the two groups of patients who fasted. RGV measurements in Group 1 (14 ± 3 ml) were similar to those in Group 2 (11 ± 2 ml) and were significantly less than ( p < 0.05) those in Group 3 (26 ± 4 ml). Gastric pH was significantly higher ( p < 0.001) in Group 1 (5.16 ± 0.69) and Group 2 (5.78 ± 0.43) than in Group 3 (1.97 ± 0.27). Conclusions: Three hundred and sixty ml of apple juice consumed within 4 hours of elective surgery by patients given ranitidine and metoclopramide did not worsen gastric volume and acidity.