A comparison of the effects of ranitidine and omeprazole on volume and pH of gastric contents in elective surgical patients:

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

Background and Aims

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.

Material and Methods

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.

Results

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).

Conclusion

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.

Practice Guidelines for Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration: Application to Healthy Patients Undergoing Elective Procedures

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Split-dose sodium picosulfate-magnesium citrate colonoscopy preparation achieves lower residual gastric volume with higher cleansing effectiveness than a previous-day regimen

BACKGROUND AND AIMS

It is known that sodium picosulfate-magnesium citrate (SPMC) bowel preparations are effective, well tolerated and safe, and that split-dosing is more effective for colon cleansing than previous-day regimens. Anesthetic guidelines consider that residual gastric fluid is independent of clear liquid fasting times. However, reluctance to use split-dosing persists. This may be due to limited data on residual gastric fluid volumes (RGFVs) and split-dosing bowel preparations, and that these may not be perceived as standard clear liquids. Furthermore, no studies are available on RGFV/residual gastric fluid pH (RGFpH) and SPMC. We aimed to evaluate the cleansing effectiveness and the RGFV/RGFpH achieved after an SPMC split-dosing regimen compared with a SPMC previous-day regimen.

METHODS

This was a single-center observational study. A total of 328 outpatients scheduled for simultaneous EGD and colonoscopy and following a split-dosing or previous-day regimen of SPMC were included. We prospectively measured colon cleanliness by using the Ottawa Bowel Preparation Scale, RGFV, and RGFpH.

RESULTS

Ottawa Bowel Preparation Scale scores for overall, right, mid-colon, and colon fluid were significantly better in the split-dosing group. In the split-dosing group, the 3- to 4-hour fasting time consistently achieved the best cleansing quality. RGFV was significantly lower in the split-dosing group (11.09 vs 18.62, P < .001). No significant differences in RGFpH were detected.

CONCLUSIONS

Split-dosing SPMC provides higher colon cleansing quality with lower RGFVs than previous-day SPMC regimens. SPMC in split-dosing acts exactly as a standard clear liquid acts, and thus anesthetic guidelines on this issue may be applied with no concerns.

Meta-analysis: comparative efficacy of H2-receptor antagonists and proton pump inhibitors for reducing aspiration risk during anaesthesia depending on the administration route and schedule

H2-receptor antagonists (H2RA) and proton pump inhibitors (PPI) are widely used for aspiration prophylaxis in patients receiving general anaesthesia. Many randomized trials have compared these agents but it remains unclear which drug type is more effective in reducing the number of patients at risk of complications. The study aimed to compare their efficacy for decreasing the number of patients at risk of acid aspiration during general anaesthesia. Major databases were systematically searched. Randomized controlled trials comparing PPI and H2RA were selected. Sub-analyses were performed considering the dose, the dosing schedule, and the route of administration. Eighteen studies fulfilled the inclusion criteria. The main analysis showed a non-significant trend for H2RA being more effective than PPI. Only when both drugs were administered per os, as a single dose and immediately before surgery, was H2RA significantly more effective than PPI. By contrast, the effect of PPI and H2RA was similar when they were administered in two doses (the night before and on the morning of surgery) or when the drugs were given intravenously. A single H2RA dose before surgery is highly effective in reducing the number of patients at risk of acid aspiration. PPI administered in two oral doses or in a single intravenous infusion seems to be as effective as H2RA.

Hypersensitivity reaction to ranitidine: description of a case and review of the literature

Ranitidine is an H2-receptor antagonist which is usually well tolerated. Hypersensitivity reactions to ranitidine, as well as other H2 antihistamines, have been rarely described. We report the case of a 47-year-old woman who developed an anaphylactic reaction to ranitidine used as intravenous premedication before anesthesia induction. The patient's history revealed that previous use of oral ranitidine for a peptic ulcer disease did not cause any adverse reaction. Intradermal test with ranitidine at a dilution of 1:100 gave an intense positive reaction. The protective role of H2-receptor antagonists as premedication is still unclear and should be carefully reconsidered on the basis of the available controversial evidence and the possible risk of hypersensitivity reactions.

Do proton-pump inhibitors increase the risk for nosocomial pneumonia in a medical intensive care unit?

PURPOSE

The aim of this study was to determine whether the use of gastric acid-suppressive agents increases the risk of nosocomial pneumonia (NP) in a medical intensive care unit population.

MATERIALS AND METHODS

Retrospective cohort study in a medical intensive care unit of a 554-bed, university-affiliated, academic medical center.

RESULTS

A total of 924 medical records were included in the database during the study period of which 787 patients were included in the study. Out of this cohort,104 patients (13.2%) eventually developed a NP. The risk for patients who received proton-pump inhibitors (adjusted hazard ratio [AHR] 0.63; 95% CI 0.39-1.01) was not significantly different than in non exposed patients. Variables most strongly associated with NP were the administration of sedatives or neuromuscular blockers for at least 2 consecutive days (AHR 3.39;95% CI 1.99-5.75), an Acute Physiology and Chronic Health Evaluation II (APACHE II) severity score greater than 15 (AHR, 3.34; 95% CI 1.82-6.50), and presence of a central venous catheter (AHR, 1.76; 95% CI 1.12-2.76).

CONCLUSIONS

Prior use of a proton-pump inhibitor did not correlate with a significant increase in the risk of developing NP. This risk was higher with the administration of sedatives or neuromuscular blockers, increased disease severity, and placement of a central venous catheter.

Effect of preoperative intravenous pantoprazole in elective-surgery patients: a pilot study

BACKGROUND

This study evaluated the effects of intravenous pantoprazole on gastric volume and acid output in elective-surgical patients.

METHODS

This is a multicenter, randomized, pilot study of adult patients receiving intravenous pantoprazole: 40 mg every 24 h, 40 mg every 12 h (q12h) or 80 mg q12h. The first dose was administered 1 h before general anesthesia for surgery. All gastric fluid was aspirated through a nasogastric tube 1 h before dosing and through the postoperative period. Aspirate volume was recorded; pH and H(+) concentrations were measured.

RESULT

Twenty-six patients were enrolled and 21 were evaluable. Pantoprazole was well tolerated. All regimens decreased gastric acid output and volume, and increased pH within 1 h of dosing. Effects were sustained for up to 12 h following single-dose administration.

CONCLUSIONS

Intravenous pantoprazole administered prior to anesthesia induction may be efficacious for the reduction of gastric volume and acid output, and for pulmonary aspiration prophylaxis in surgical patients.

Extending acute trials to remote populations: a pilot study during interhospital helicopter transfer

BACKGROUND AND PURPOSE

Methods to increase recruitment into acute stroke trials are needed. The purposes of this study were to evaluate the safety and acceptability of initiating acute stroke trials during early helicopter evacuation and to test an intervention to facilitate informed consent.

METHODS

A randomized, controlled trial was done with patients with acute stroke who were transferred by helicopter to the University of Iowa Hospitals and Clinics from February 2007 to January 2008. The intervention to be evaluated was the use of fax and a telephone call to the patient/surrogate ahead of helicopter arrival at the outside emergency department. The aim was to improve the rate of subsequent consent (primary outcome) for a pilot trial of a potentially beneficial, low-risk medical intervention (ranitidine) to prevent aspiration pneumonitis. Consenting eligible patients received the infusion during the flight to University of Iowa Hospitals and Clinics.

RESULTS

One hundred patients were enrolled. Consent rate was 54% in the intervention group and 50% in the control group (P=0.69). However, the consent rate was higher (69%) when prearrival communications between the coinvestigator and potential subjects were successful (P=0.04). This approach resulted in an average gain of 59 minutes as compared with initiating recruitment on arrival to University of Iowa Hospitals and Clinics.

CONCLUSIONS

Enrollment into stroke intervention trials is feasible during helicopter transportation from a community hospital emergency department to a tertiary stroke center. This underused resource may improve trial efficiency by enabling and expediting participation of remote populations currently excluded from research. Consent rates might be further improved by communication strategies that are more successful in reaching patients at outside emergency departments.