Stress-related mucosal disease in the critically ill patient: risk factors and strategies to prevent stress-related bleeding in the intensive care unit

Risk factors for gastric mucosa lesion in critically ill patients undergoing endoscopy for percutaneous gastrostomy: a case-control study

BACKGROUND

Pharmacologic prophylaxis for gastric ulcer is commonly prescribed in patients hospitalized in the intensive care unit (ICU). The aim of the study was to assess the current prevalence and risk factors for gastric mucosa lesion in ICU patients receiving standard pharmacologic prophylaxis undergoing endoscopy for percutaneous gastrostomy implantation.

METHODS

Patients hospitalized in the mixed medical-surgical ICU undergoing percutaneous endoscopic gastrostomy (PEG) were analyzed. We excluded patients receiving either no or high doses of intravenous proton pump inhibitor (PPI), only patients receiving standard doses of PPI were included. Data retrieved from the electronic medical records included: demographics, risk factors for gastric mucosa lesion (use of stimulants, comorbidities, medications, treatment methods in the ICU, laboratory derangements) and endoscopic findings. The study compared a group of patients with gastric mucosa lesions (cases) vs. patients without gastric mucosa lesions (controls). Inter-group comparisons between cases and controls were performed. Depending on the type of distribution continuous variables were assessed using two-sample t-test or Mann-Whitney test, whereas categorical variables with Chi-squared or Fisher exact test. Odds ratio (OR) with 95% confidence interval (95% CI) were calculated. Statistical significance was assumed at p < 0.05.

RESULTS

Patients with no prophylaxis (n = 8) or receiving high doses (> 40 mg per day) of proton pump inhibitor (n = 2) were excluded. There were 182 patients receiving standard intravenous dose of PPI, 63 (34.6%) women and 119 (65.4%) men, with median age 61.5 (interquartile range IQR 46.0-70.0) years. Majority of patients (n = 169, 92.9%) were receiving pharmacological prophylaxis for venous thromboembolism. There were 53 (29.1%) patients with gastric mucosa lesion. The only risk factor that was significantly different between cases and controls was history of gastric ulcer (p = 0.04) with OR 3.8 (95% CI 1.1-12.5; p = 0.03).

CONCLUSIONS

Majority of various risk factors for gastric ulceration may not predict gastric mucosa lesion in ICU patients receiving standard pharmacological prophylaxis undergoing endoscopy for PEG implantation. We found that history of gastric ulcer may be a risk factor for gastric ulceration in the ICU patients. Patients with history of gastric ulcer might benefit from higher than standard doses of anti-ulcer medication when hospitalized in the ICU.

A Review of Population Pharmacokinetic Models of Posaconazole

Posaconazole is often used for the prophylaxis and treatment of invasive fungal infections (IFI). However, intra- and inter-individual differences and drug interactions affect the efficacy and safety of posaconazole. Precision dosing of posaconazole based on the population pharmacokinetic (PopPK) model may assist in making significant clinical decisions. This review aimed to comprehensively summarize the published PopPK models of posaconazole and analyze covariates that significantly influence posaconazole exposure. Articles published until May 2022 for PopPK analysis of posaconazole were searched in PubMed and EMBASE databases. Demographic characteristics, model characteristics, and results of PopPK analysis were extracted from the selected articles. In addition, the steady-state pharmacokinetic profiles of posaconazole were simulated at different covariate levels and dosing regimens. Out of the 13 studies included in our review, nine studies included adults, three included children, and one included both adults and children. All oral administration models were one-compartment models, and all intravenous administration models were two-compartment models. Body weight, proton pump inhibitors, and incidence of diarrhea were found to be important covariates. Clinically, the potential impact of factors such as patient physiopathologic characteristics and comorbid medications on posaconazole pharmacokinetics should be considered. Dose adjustment in combination with TDM or replacement with a tablet or intravenous formulation with higher exposure may be an effective way to ensure drug efficacy as well as to reduce fungal resistance. Meanwhile, published models require further external evaluation to examine extrapolation.

Integrating Multidisciplinary Individualized Medication Recommendations Into the Traditional Pharmacists' Consultation Method: A Retrospective Study Using Propensity Score Matching Analysis

Chinese clinical pharmacists consider improving the quantity and quality of consultations to be an important task in providing better pharmaceutical care. To achieve this goal, we developed a clinical pharmacist consultation method using multidisciplinary individualized medication recommendations (MIMRs) and studied the effects of its implementation. A retrospective study of 812 clinical pharmacist-led consultations was conducted. In the pre-intervention group, medication advice was given based on the purpose of the consultation. In the post-intervention group, a consultation method using MIMRs was implemented, in which clinical pharmacists with specialties in anticoagulation, gastroenterology, and nutrition were asked to give individualized medication recommendations. Outcomes, including the effectiveness rate of consultations (ERC) and acceptance rate of consultations (ARC), were compared between the two groups using propensity score matching method. Patterns and numbers of consultations and individualized medication recommendations were also compared. The results showed that the ERC in the post-intervention group compared with the ERC in the pre-intervention group was 83.3% vs 74.0%, respectively (P < .05). Significant difference was also shown between the two groups in ARC (98.4% vs 92.2%, P < .05). The total number of consultations increased, as did the number of general consultations, multidisciplinary/difficult consultations, anti-infection consultations, and non-anti-infection consultations specifically. As a result, we proposed that the implementation of MIMRs can improve the effects of treatment and increase the number of consultations by pharmacists, which is worthy of further promotion to better serve physicians and patients.

Prognosis of patients with tracheal intubation in the emergency department

Background

Intubation of critically ill patients is one of the increasing emergency procedures. We designed this study to determine age and sex-related mortality rates after emergency intubation.

Methods

This retrospective study collected and analyzed non-trauma intubated patients in a referral hospital from the years 2017-2019 and before the appearance of COVID-19. Patients who were intubated outside of emergency by EMS technicians were excluded. We recorded data of intubated patients, like sex, age, length of being intubated and final diagnosis. P values of less than 0.05 were significant.

Results

Data of 520 non-trauma intubated patients were collected and analyzed. More than 64% of the patients were over 65 years old and had a higher mortality rate (86.7%; P < 0.001) than younger patients. The overall in-hospital mortality rate was 80%. More than three quarters of the decedents died within a week of intubation (P < 0.001). There was no significant relationship between sex and mortality rate (P = 0.535).

Conclusion

Our data showed that with increased age there was a decrease in the chance of being extubated.

Stress-Related Gastrointestinal Bleeding in Patients with Aneurysmal Subarachnoid Hemorrhage: A Multicenter Retrospective Observational Study

BACKGROUND/OBJECTIVE

Stress-related mucosal bleeding (SRMB) occurs in approximately 2-4% of critically ill patients. Patients with aneurysmal subarachnoid hemorrhage (aSAH) have a (diffuse) space-occupying lesion, are critically ill, often require mechanical ventilation, and frequently receive anticoagulation or antiplatelet therapy after aneurysm embolization, all of which may be risk factors for SRMB. However, no studies have evaluated SRMB in patients with aSAH. Aims of the study were to determine the incidence of SRMB in aSAH patients, evaluate the effect of acid suppression on SRMB, and identify specific risk factors for SRMB.

METHODS

This was a multicenter, retrospective, observational study conducted across 17 centers. Each center reviewed up to 50 of the most recent cases of aSAH. Patients with length of stay (LOS) < 48 h or active GI bleeding on admission were excluded. Variables related to demographics, aSAH severity, gastrointestinal (GI) bleeding, provision of SRMB prophylaxis, adverse events, intensive care unit (ICU), and hospital LOS were collected for the first 21 days of admission or until hospital discharge, whichever came first. Descriptive statistics were used to analyze the data. A multivariate logistic regression modeling was utilized to examine the relationship between specific risk factors and the incidence of clinically important GI bleeding in patients with aSAH.

RESULTS

A total of 627 patients were included. The overall incidence of clinically important GI bleeding was 4.9%. Of the patients with clinically important GI bleeding, 19 (61%) received pharmacologic prophylaxis prior to evidence of GI bleeding, while 12 (39%) were not on pharmacologic prophylaxis at the onset of GI bleeding. Patients who received an acid suppressant agent were less likely to experience GI bleeding than patients who did not receive pharmacologic prophylaxis prior to evidence of bleeding (OR 0.39, 95% CI 0.18-0.83). The multivariate regression analysis identified any instance of elevated intracranial pressure, creatinine clearance < 60 ml/min and the incidence of cerebral vasospasm as specific risk factors associated with GI bleeding. Cerebral vasospasm has not previously been described as a risk for GI bleeding (OR 2.5 95% CI 1.09-5.79).

CONCLUSIONS

Clinically important GI bleeding occurred in 4.9% of patients with aSAH, similar to the general critical care population. Risk factors associated with GI bleeding were prolonged mechanical ventilation (> 48 h), creatinine clearance < 60 ml/min, presence of coagulopathy, elevation of intracranial pressure, and cerebral vasospasm. Further prospective research is needed to confirm this observation within this patient population.

Sepsis as an important risk factor for gastrointestinal bleeding in acute coronary syndrome patients: Two case reports

RATIONALE

Sepsis is a common stressor that may decrease microcirculation in the gastrointestinal tract in patients and increase the gastrointestinal bleeding risk of stress-related mucosal disease. However, the CRUSADE (Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the ACC/AHA Guidelines) bleeding risk score, recommended by authoritative guidelines for acute coronary syndrome (ACS), does not include sepsis as a bleeding risk factor.

PATIENT CONCERNS

The 2 cases were about ACS with hemorrhagic complications. The first patient was an 88-year-old man with hypertension, gallstones, hepatic cysts, and chest pain; the second one was a 79-year-old man with chest pain and hypertension. These 2 ACS patients had no bleeding on admission; however, both patients suffered apparent gastrointestinal bleeding immediately after the development of sepsis or severe sepsis.

DIAGNOSES

Both patients were diagnosed as ACS with sepsis.

INTERVENTIONS

The first ACS patient had no use of proton pump inhibitors (PPIs) for prophylaxis prior to the diagnosis of sepsis. The second one was administered PPIs at standard oral doses.

OUTCOMES

The first patient suffered from gastrointestinal bleeding immediately after the onset of sepsis. And oral PPIs failed to prevent upper gastrointestinal bleeding for the second patient, when severe sepsis developed. However, the second patient's gastrointestinal hemorrhage gradually stopped immediately after high doses of PPIs were administered intravenously, rather than orally. When sepsis developed again, the second patient also had no recurrent gastrointestinal bleeding under the protection of PPIs at standard oral doses.

LESSONS

Our report suggests that sepsis may be an important bleeding risk factor for ACS patients, and the reasonable use of PPIs to prevent gastrointestinal bleeding could be vital for ACS patients complicated with sepsis.

Failure of gastric prophylaxis against stress bleeding reflects inadequate pH control

BACKGROUND

Gastric prophylaxis against stress ulceration with histamine 2 blockers or protein pump inhibitors is a quality standard in septic Surgical Intensive Care Unit (SICU) patients to reduce gastric pH below 3.5. This study assesses the efficacy of gastric prophylaxis with pH monitoring.

METHODS

A total of 100 patients were studied for 481 days. All received histamine 2 blockers or protein pump inhibitors. Daily pH control was judged as poor (1-3), moderate (4-5), or good (>5). Patients with poor pH received double-dose or an infusion gastric prophylaxis. Nasogastric tube bile or blood and transfusions for stress ulceration were recorded.

RESULTS

Gastric prophylaxis was poor for 37 days, moderate for 83 days, and good for 279 days. NGT blood occurred on 15 days (40%) with poor, 17 days (20%) with moderate, and 17 days (6%) with good control. Transfusions for stress ulceration occurred on 5 days (14%) during poor, 3 days (4%) during moderate, and 1 day (0.3%) during good control (P < .05). Enhanced gastric prophylaxis improved pH control and reduced nasogastric tube blood. Transfusion for stress ulceration after enhanced therapy was required on 1 day (8%) with poor control and never for moderate or good control.

CONCLUSION

Gastric prophylaxis against stress ulceration should be monitored by nasogastric tube pH.

Profile of peptic ulcer disease and its risk factors in Arar, Northern Saudi Arabia

Background

Peptic ulcer disease is a multifactorial health problem, and its prevalence and risk factors have changed considerably within the past century.

Objective

To determine the prevalence of peptic ulcer among the population of Arar city and to identify risk factors for peptic ulcer and to estimate their relative impact on ulcer incidence.

Methods

A cross-sectional study was carried out on the population of Arar city, Northern Saudi Arabia from November 01, 2016 to April 30, 2017. Data were analyzed by SPSS version 16, using descriptive statistics, prevalence, and Chi-square test.

Results

Total prevalence of peptic ulcer among the studied respondents was thus: 21.9% had peptic ulcer; 16.2% gastric ulcer and 5.6% duodenal ulcer. In 19.7% of the cases, the pain was severe, 92.4% reported that pain was precipitated by certain food. In addition to heartburn, 78.8% reported loss of appetite, 71.2% indigestion, 66.7% regurgitation, 59.1% nausea and vomiting and 42.4% with chest pain. Regarding the risk factors, coffee drinking came in first place (81.8%) followed by physical stress in 77.3%, spicy food in 57.6%, prolonged use of Non-steroidal anti-inflammatory drugs (NSAIDs) in 33.3% and Helicobacter pylori (H. pylori) infection in 24.2%. A further 22.7% reported melena as a complication while only 10.6% reported hematemesis.

Conclusion

This is the first population-based study in Arar, Northern Saudi Arabia reporting point prevalence of peptic ulcer disease. The rate of 16.2% for gastric ulcer and 5.6% for duodenal ulcers are substantially high. Coffee drinking, physical stress, spicy food, prolonged use of NSAID and H. pylori infection were the reported risk factors. Population-based endoscopic studies are recommended.

Current Concepts in Severe Sepsis and Septic Shock

Sepsis is a frequent cause of presentation to the emergency department (ED). Early identification and aggressive management in the ED is paramount to improving morbidity and mortality associated with sepsis. As a result, pharmacists in the ED should be familiar with and assist with the optimization of therapy for sepsis in this patient population. This article will discuss the epidemiology and economic impact of sepsis and the definitions, pathophysiology, and clinical presentation of sepsis and its related syndromes. In addition, the authors will discuss the elements related to treatment of sepsis from the Surviving Sepsis Campaign Guidelines that are particularly germane to the management of sepsis in the ED. Direct support such as source control, early broad-spectrum antibiotic therapy, hemodynamic assessment, and continuous monitoring are essential. In addition, early aggressive fluid resuscitation with titration of therapy to mixed venous oxygen saturation >70%, tight glycemic control and choice of vasopressors and inotropes have been shown to decrease mortality in sepsis. Mechanical ventilation with low tidal volumes, renal replacement therapies, early enteral nutritional support, and stress ulcer prophylaxis are also important considerations in septic patients. Controversies in therapy such as the utility of drotrecogin α activated, low-dose corticosteroids, and vasopressin are also discussed.

Population pharmacokinetics of omeprazole in critically ill pediatric patients

BACKGROUND

To develop a population pharmacokinetic model for intravenous omeprazole in critically ill children.

METHODS

One hundred eighty-six omeprazole concentration-time data from 40 critically ill children were analyzed using the nonlinear mixed-effects approach with the nonlinear mixed-effects modeling software, version 7.2 software. Patients were randomized into 2 groups and received intravenous omeprazole at a dose of 0.5 or 1 mg/kg twice daily. Blood samples were drawn at 0.5, 2, 6, 12, 24, and 48 hours after the first infusion.

RESULTS

The pharmacokinetic profile was best described by a 2-compartment model with a first-order elimination process. Between-patient variability could only be associated with plasma clearance (CL). The typical values for plasma CL were 24.9 L·h·70 kg (10.08%), with a distributional clearance of 53.9 L·h·70 kg (11.00%) and central and peripheral compartment distribution volumes of 4.23 L/70 kg (19.62%) and 674 L/70 kg (0.89%), respectively. Allometric size models seemed to predict changes adequately in all the pharmacokinetic parameters. High values of between-patient variability of CL [75.50% (2.60%)] and residual variability [130.0% (5.26%)] were still found in the final model. Model-based simulations suggested that the most suitable dose was 1 mg/kg because this yielded similar exposure (defined by the area under the concentration-time curve) to that obtained in adults after a 20-mg dose of omeprazole intravenously.

CONCLUSIONS

An allometric size model allows changes to be predicted in all the pharmacokinetic parameters, making dose adjustment by body weight important to achieve the most effective omeprazole exposure. This is the first step toward a population pharmacokinetic study, including more data to develop a predictable model to be used during therapeutic drug monitoring.

Stress-related mucosal disease in the critically ill patient

Bleeding from stress-related mucosal disease in critically ill patients remains an important clinical management issue. Although only a small proportion (1-6%) of patients admitted to an intensive care unit (ICU) will bleed, a substantial proportion exhibit clinical risk factors (mechanical ventilation for >48 h and a coagulopathy) that predict an increased risk of bleeding. Furthermore, upper gastrointestinal mucosal lesions can be found in 75-100% of patients in ICUs. Although uncommon, stress-ulcer bleeding is a severe complication with an estimated mortality of 40-50%, mostly from decompensating an underlying condition or multiorgan failure. Although the vast majority of patients in ICUs receive stress-ulcer prophylaxis, largely with PPIs, some controversy surrounds their efficacy and safety. Indeed, no single trial has shown that stress-ulcer prophylaxis reduces mortality. Some reports suggest that the use of PPIs increases the risk of nosocomial infections. However, several meta-analyses and cost-effectiveness studies suggest PPIs to be more clinically effective and cost-effective than histamine-2 receptor antagonists, without considerable increases in nosocomial pneumonia. To help clinicians use the most appropriate strategy for treatment of patients in the ICU, this Review presents the latest information on all aspects of stress-related mucosal disease.

The comparison of extemporaneous preparations of omeprazole, pantoprazole oral suspension and intravenous pantoprazole on the gastric pH of critically ill-patients

Background:

Stress-related mucosal disease occurs in many critically ill-patients within 24 h of admission. Proton pump inhibitor therapy has been documented to produce more potent inhibition of gastric acid secretion than histamine 2 receptor antagonists. This study aimed to compare extemporaneous preparations of omeprazole, pantoprazole oral suspension and intravenous (IV) pantoprazole on the gastric pH in intensive care unit patients.

Materials and Methods:

This was a randomized single-blind-study. Patients of ≥ 16 years of age with a nasogastric tube, who required mechanical ventilation for ≥ 48 h, were eligible for inclusion. The excluded patients were those with active gastrointestinal bleeding, known allergy to omeprazole and pantoprazole and those intolerant to the nasogastric tube. Fifty-six patients were randomized to treatment with omeprazole suspension 2 mg/ml (40 mg every day), pantoprazole suspension 2 mg/ml (40 mg every day) and IV pantoprazole (40 mg every day) for up to 14 days. Gastric aspirates were sampled before and 1-2.5 h after the drug administration for the pH measurement using an external pH meter. Data were analyzed using SPSS (version 21.0).

Results:

In this study, 56 critically ill-patients (39 male, 17 female, mean age: 61.5 ± 15.65 years) were followed for the control of the gastric pH. On each of the 14 trial days the mean of the gastric pH alteration was significantly higher in omeprazole and pantoprazole suspension-treated patients than in IV pantoprazole-treated patients (P < 0.001).

Conclusion:

Omeprazole and pantoprazole oral suspension are more effective than IV pantoprazole in increasing the gastric pH.

Potential costs of inappropriate use of proton pump inhibitors

BACKGROUND

Proton pump inhibitors (PPIs) are commonly overused in hospitalized patients. The objectives of this study were to determine the extent of their inappropriate initiation in patients with low risk for gastrointestinal hemorrhage, factors associated with their continuation on discharge and potential cost of this trend.

METHODS

Retrospective examination of patients with low risk for gastrointestinal hemorrhage admitted to a tertiary-care teaching hospital over a 3-month period who received esomeprazole. The following information was collected: age, gender, PPI status (de novo or continued) and admitting diagnoses. Additional information collected from the de novo subgroup included indication for PPI, number of days on PPI and continuation of the drug on discharge. The cost of the medication was obtained from pharmacy records.

RESULTS

Four hundred nine patients were admitted during the study period and 204 (49.9%) received PPI de novo. Among these, 155 patients (76%) had an inappropriate indication for PPI. Of these, 62 (40%) patients were continued on PPI on discharge. Older age was a significant predictor of continuation of PPI at discharge. The estimated cost of the inpatient and outpatient inappropriate use of PPI was $12,272 and $59,272, respectively.

CONCLUSIONS

PPIs are overused in the majority of hospitalized patients with low risk for gastrointestinal bleeding and this practice gets perpetuated at discharge, especially in older patients. The cost of this phenomenon is alarming.

Gastroesophageal reflux during enteral feeding in stroke patients: a 24-hour esophageal pH-monitoring study

BACKGROUND

Patients who are unable to eat or drink after stroke may receive percutaneous endoscopic gastrostomy (PEG) or nasogastric tube feeding. Although the most common serious complication is well known to be aspiration pneumonia, the role of gastroesophageal reflux (GER) has not been fully assessed. The aim of this study was to examine, by means of 24-hour esophageal pH monitoring, whether GER is related to aspiration pneumonia and whether the size and laterality of brain lesions influence GER.

METHODS

Sixteen stroke patients were examined using a Degitrapper pH400 (Medtronic Japan Co., Tokyo, Japan) and Zinetics 24ME multiuse pH catheter (Medtronic). All patients had stroke lesions in the territory of the left or right middle cerebral artery that were confirmed by magnetic resonance imaging (MRI) and were receiving PEG or nasogastric feeding. Stroke volume was measured with MRIcron software.

RESULTS

Nine patients (56%) were diagnosed with GER, and 10 (63%) developed aspiration pneumonia after enteral feeding. The rate of aspiration pneumonia was significantly higher in patients with GER (88.9%) than in those without GER (42.9%; P = .04). Patients with left hemispheric lesions had a significantly higher incidence of acid reflex than those with right lesions (116 ± 105 vs 13 ± 17; P = .04). There were no significant differences in total time of acid reflux or mean pH value between patients with left and right hemispheric lesions. The lesion volume had no significant effect on any of 3 indices of GER.

CONCLUSIONS

GER is associated with aspiration pneumonia and occurs more often in patients with stroke lesions in the left hemisphere.

0.5 mg/kg versus 1 mg/kg of intravenous omeprazole for the prophylaxis of gastrointestinal bleeding in critically ill children: a randomized study

OBJECTIVE

To compare the effect of 2 doses of intravenous omeprazole on gastric pH, gastrointestinal bleeding, and adverse effects in critically ill children.

STUDY DESIGN

We undertook a prospective randomized clinical trial in critically ill children at risk of gastrointestinal bleeding. The effect of 2 intravenous omeprazole regimens (0.5 or 1 mg/kg every 12 hours) on the gastric pH and incidence of gastrointestinal hemorrhage was compared. The efficacy criteria were a gastric pH >4 and the absence of clinically significant gastrointestinal bleeding.

RESULTS

Forty patients, 20 in each treatment group, were studied. Overall, the gastric pH was greater than 4 for 57.8% of the time, with no difference between the doses (P = .66). The percentage of time with a gastric pH > 4 increased during the study (47.8% between 0 and 24 hours vs 76% between 24 and 48 hours, P = .001); the greater dose showed a greater increase in the percentage of time with a pH > 4: between hours 24 and 48 of the study, the gastric pH was greater than 4 for 84.5% of the time with the 1 mg/kg dose and for 65.5% of the time with the 0.5 mg/kg dose (P = .036). Plasma omeprazole levels were greater with 1 mg/kg dose, but no correlation was found between omeprazole plasma levels and gastric pH. No toxic adverse effects were detected, and there was no clinically significant bleeding.

CONCLUSION

Neither of the 2 omeprazole regimens achieved adequate alkalinization of the gastric pH during the first 24 hours. Between 24 and 48 hours, the 1 mg/kg dose maintained the gastric pH greater than 4 for a greater percentage of the time.

[Hemodynamic effects of intravenous omeprazole in critically ill children]

INTRODUCTION

Critical patients usually have hemodynamic disturbances which may become worse by the administration of some drugs. Omeprazole is a drug used in the prophylaxis of the gastrointestinal bleeding in these patients, but its cardiovascular effects are unknown. The objective was to study the hemodynamic changes produced by intravenous omeprazole in critically ill children and to find out if there are differences between two different doses of omeprazole.

MATERIAL AND METHODS

A randomized prospective observational study was performed on 37 critically ill children aged from 1 month to 14 years of age who required prophylaxis for gastrointestinal bleeding. Of these, 19 received intravenous omeprazole 0.5mg/kg every 12 hours, and 18 received intravenous omeprazole 1mg/kg every 12 hours. Intravenous omeprazole was administered in 20 minutes by continuous infusion pump. Heart rate, systolic, diastolic and mean arterial blood pressure, central venous pressure and ECG were recorded at baseline, and at 15, 30, 60 and 120 minutes of the infusion.

RESULTS

There were no significant changes in the electrocardiogram, heart rate, blood pressure and central venous pressure. No patients required inotropic therapy modification. There were no differences between the two doses of omeprazole.

CONCLUSIONS

Intravenous omeprazole administration of 0.5mg/kg and 1mg/kg is a hemodynamically safe drug in critically ill children.

A review of stress-related mucosal disease

OBJECTIVE

To review and summarize the human and veterinary literature regarding stress-related mucosal disease (SRMD) pathogenesis, patient risk factors, and therapeutic options for prophylaxis and treatment.

ETIOLOGY

SRMD is a common sequela of critical illness in human patients. Development of SRMD results from splanchnic hypoperfusion, reperfusion injury, and exposure of the gastric mucosa to acid, pepsin, and bile acids following breakdown of the gastric mucosal defense system. Human patients with the highest risk of stress ulceration include those with respiratory failure necessitating mechanical ventilation greater than 48 h or coagulopathy. Currently, little is known about the incidence and pathophysiology of SRMD in critically ill veterinary patients.

DIAGNOSIS

A presumptive diagnosis can be made in high-risk patient populations following detection of occult or gross blood in nasogastric tube aspirates, hematemesis, or melena. Definitive diagnosis is achieved via esophagogastroduodenoscopy. Lesions are localized to the acid-producing portions of the stomach, the fundus, and body.

THERAPY

Therapy is aimed at optimization of tissue perfusion and oxygenation. Pharmacologic interventions are instituted to increase intraluminal pH and augment natural gastric defenses. Histamine(2)-receptor antagonists, proton pump inhibitors, and sucralfate are the mainstays of therapy. In people, clinically significant bleeding may necessitate additional interventions (eg, packed red blood cell transfusions, endoscopic, or surgical hemostasis).

PROGNOSIS

Mortality is increased in people with clinically significant bleeding compared to those patients who do not bleed. Institution of prophylaxis is recommended in high-risk patients. However, no consensus exists regarding initiation of prophylaxis, preference of frontline drug class, or indication for discontinuation of therapy. The prognosis of veterinary patients with SRMD remains unknown at this time.

The use of mechanical ventilation in the ED

OBJECTIVES

Although EDs are responsible for the initial care of critically ill patients and the amount of critical care provided in the ED is increasing, there are few data examining mechanical ventilation (MV) in the ED. In addition, characteristics of ED-based ventilation may affect planning for ventilator shortages during pandemic influenza or bioterrorist events. The study examined the epidemiology of MV in US EDs, including demographic, clinical, and hospital characteristics; indications for MV; ED length of stay (LOS); and in-hospital mortality.

METHODS

This study was a retrospective review of the 1993 to 2007 National Hospital Ambulatory Medical Care Survey ED data sets. Ventilated patients were compared with ED patients admitted to the intensive care unit (ICU) and to all other ED visits.

RESULTS

There were 3.6 million ED MV visits (95% confidence interval [CI], 3.2-4.0 million) over the study period. Sex, age, race, and payment source were similar for mechanically ventilated and ICU patients (P > .05 for all). Approximately 12.5% of ventilated patients underwent cardiopulmonary resuscitation compared with 1.7% of ICU admissions and 0.2% of all other ED visits (P < .0001). Accordingly, in-hospital mortality was significantly higher for ventilated patients (24%; 95% CI, 13.1%-34.9%) than both comparison groups (9.3% and 2.5%, respectively). Median LOS for ventilated patients was 197 minutes (interquartile range, 112-313 minutes) compared with 224 minutes for ICU admissions and 140 minutes for all other ED visits.

CONCLUSIONS

Patients undergoing ED MV have particularly high in-hospital mortality rates, but their ED LOS is sufficient for implementation of evidence-based ventilator interventions.

A marked increase in gastric fluid volume during cardiopulmonary bypass

Major physiological stress occurs during cardiac surgery with cardiopulmonary bypass. This is related to hypothermia and artificial organ perfusion. Thus, serious gastrointestinal complications, particularly upper gastrointestinal bleeding, sometimes follow cardiac surgery. We have compared the antisecretory effects of a preanesthetic H(2) antagonist (roxatidine, cardiopulmonary bypass-H(2) group, n = 15) and a proton pump inhibitor (rabeprazole, cardiopulmonary bypass-PPI group, n = 15) in patients undergoing cardiac surgery with cardiopulmonary bypass, and also compared in patients undergoing a off-pump coronary artery bypass graft surgery (off-pump cardiopulmonary bypass-H(2) group, n = 15). Gastric pH (5.14 ± 0.61) and gastric fluid volume (13.2 ± 2.4 mL) at the end of surgery in off-pump cardiopulmonary bypass-H(2) groups was significantly lower and higher than those in both cardiopulmonary bypass-H(2) (6.25 ± 0.54, 51.3 ± 8.0 mL) and cardiopulmonary bypass-PPI (7.29 ± 0.13, 63.5 ± 14.8 mL) groups, respectively although those variables did not differ between groups after the induction of anesthesia. Plasma gastrin (142 ± 7 pg/mL) at the end of surgery and maximal blood lactate levels (1.50 ± 0.61 mM) in off-pump cardiopulmonary bypass-H(2) group were also significantly lower than those in both cardiopulmonary bypass-H(2) (455 ± 96 pg/mL, 3.97 ± 0.80 mM) and cardiopulmonary bypass-PPI (525 ± 27 pg/mL, 3.15 ± 0.44 mM) groups, respectively. In addition, there was a significant correlation between gastric fluid volume and maximal blood lactate (r = 0.596). In conclusion, cardiopulmonary bypass may cause an increase in gastric fluid volume which neither H(2) antagonist nor PPI suppresses. A significant correlation between gastric fluid volume and maximal blood lactate suggests that gastric fluid volume may predict degree of gastrointestinal tract hypoperfusion.

The efficacy and safety of proton pump inhibitors vs histamine-2 receptor antagonists for stress ulcer bleeding prophylaxis among critical care patients: a meta-analysis

OBJECTIVE

To examine the efficacy and safety of proton pump inhibitors in comparison with histamine-2 receptor antagonists for stress-related upper gastrointestinal bleeding prophylaxis among critical care patients.

DATA SOURCES

PubMed, EMBASE, Cochrane Library, and ClinicalTrials.gov.

STUDY SELECTION

Randomized, controlled trials that directly compare proton pump inhibitors with histamine-2 receptor antagonists in prevention of stress-related upper gastrointestinal bleeding in intensive care unit patients published before May 30, 2008.

DATA EXTRACTION

Two reviewers independently applied selection criteria, performed quality assessment, and extracted data. The primary outcome was the incidence of stress-related upper gastrointestinal bleeding, and the secondary outcome measures were the incidence of pneumonia and intensive care unit mortality.

DATA SYNTHESIS

The random effect model was used to estimate the pooled risk difference between two treatment arms irrespective of drug, dosage, and route of administration.

RESULTS

We identified seven randomized, controlled trials with a total of 936 patients for planned comparison. The overall pooled risk difference (95% confidence interval; p value; I statistics) of stress-related upper gastrointestinal bleeding comparing proton pump inhibitors vs. histamine-2 receptor antagonists was -0.04 (95% confidence interval, -0.09-0.01; p = .08; I = 66%). In the sensitivity analysis, removing the Levy study significantly reduced the heterogeneity (from I = 66% to I = 26%) and shifted the overall risk difference closer to the null (pooled risk difference, -0.02; 95% confidence interval, -0.05-0.01; p = .19). There was no difference between proton pump inhibitors and histamine-2 receptor antagonists therapy in the risk of pneumonia and intensive care unit mortality, with pooled risk differences of 0.00 (95% confidence interval, -0.04-0.05; p = .86; I = 0%) and 0.02 (95% confidence interval, -0.04-0.08; p = .50; I = 0%), respectively.

CONCLUSIONS

This meta-analysis did not find strong evidence that proton pump inhibitors were different from histamine-2 receptor antagonists in terms of stress-related upper gastrointestinal bleeding prophylaxis, pneumonia, and mortality among patients admitted to intensive care units. Because of limited trial data, future well-designed and powerful randomized, clinical trials are warranted.

Therapeutic intent of proton pump inhibitor prescription among elderly nonsteroidal anti-inflammatory drug users

BACKGROUND

Prescription of proton pump inhibitors (PPIs) has increased dramatically.

AIM

To assess therapeutic intent of PPI prescription among elderly veterans prescribed nonsteroidal anti-inflammatory drugs.

METHODS

Medical-record abstraction identified therapeutic intent of PPI prescription. An 'appropriate therapeutic intent' was defined as symptomatic gastro-oesophageal reflux disease or endoscopic oesophagitis, Zollinger-Ellison disease, dyspepsia, upper gastrointestinal event, Helicobacter pylori infection or nonsteroidal anti-inflammatory drug gastroprotection. Logistic regression predicted the outcome while adjusting for clinical characteristics.

RESULTS

Of 1491 patients [mean 73 years (s.d. 5.6), 73% white and 99.8% men], among those charts which did document a therapeutic indication, 88.8% were appropriate. Prior gastroscopy was predictive of an appropriate therapeutic intent (OR 2.7; 95% CI: 1.9-3.7). Prescription to patients who used VA pharmacy services only, to in-patients, or by a cardiologist or an otolaryngologist were less likely to be appropriate. Gastroprotection was poorly recognized as an indication for PPI prescription, except by rheumatologists (OR 46.7; 95% CI: 15.9-136.9), or among highly co-morbid patients (OR 1.8; 95% CI: 1.1-2.9). Among in-patients, 45% of PPI prescriptions were initiated for unknown or inappropriate reasons.

CONCLUSIONS

Type of provider predicts appropriate PPI use. In-patient prescription is associated with poor recognition of necessary gastroprotection and unknown therapeutic intent.

Use of intravenous proton-pump inhibitors in a teaching hospital practice

OBJECTIVE

To evaluate intravenous proton-pump inhibitor (IV PPI) prescribing in a single academic teaching hospital.

METHODS

A retrospective pilot study of 107 patients in a single United States military teaching hospital was conducted over a 1-month period. Clinical data were collected and analyzed for demographic features, prior medication use, admission hemoglobin level, service prescribing the IV PPI, indication for IV PPI, IV PPI treatment duration, gastroenterology consultant use, endoscopic findings, and blood products given. Indications for use were compared with current established guidelines to determine appropriate usage.

RESULTS

A total of 683 doses of IV pantoprazole were prescribed over a 1-month period. Seventy-six patients (71%; 95% confidence interval [CI], 62-79%) who received IV PPIs did not meet the criteria for an appropriate indication for use. Ninety-nine patients in the study (93%; 95% CI, 86-96%) met criteria for an acceptable dosage given. The most common appropriate indication given was stress ulcer prophylaxis in a high-risk setting (13%; 95% CI, 8-21%) with appropriate use of this indication 45% of the time (95% CI, 29-62%). IV PPIs were appropriately prescribed most often by the medical intensive care unit (66.7%; 95% CI, 43-84%) and least often by the surgical wards services (16%; 95% CI, 7-33%). No discernable indication was given in 52% of cases (95% CI, 43-62%), and patients were not actually nil per os in 46% of these instances (95% CI, 34-59%).

CONCLUSIONS

Intravenous PPI prescribing habits in this military hospital facility are poor. A multifaceted approach including physician/pharmacist education, IV PPI ordering templates, and a consensus medical position statement from a major gastroenterological or prominent medical association may lead to more appropriate use.

Inhibitory effects of somatostatin on cholecystokinin octapeptide induced bile regurgitation under stress: ionic and molecular mechanisms

OBJECTIVE

To investigate the possible effects and related ionic and molecular mechanisms of changes of plasma cholecystokinin octapeptide and somatostatin on stress-induced bile regurgitation in rats.

METHODS

In forty healthy adult rats, changes of plasma cholecystokinin octapeptide, somatostatin and intragastric bile concentration under stressful condition were respectively measured by specific radioimmunoassay methods. Contractile responses of gastric antral smooth strips isolated from healthy adult rats were recorded by polyphysiograph. Immunoprecipitation was used to determine the regulatory effect of protein kinase C on regulating the phosphorylation of type 3 inositol 1,4,5-triphosphate receptor (InsP3R3) in gastric smooth muscle cells. Changes of intracellular calcium fluorescence intensity of smooth muscle cells presented as intracellular calcium ([Ca2+]i) were analyzed under laser scanning confocal microscopy and L-type voltage-dependent calcium currents of smooth muscle cells were recorded by patch-clamp techniques.

RESULTS

Compared with the normal control group, plasma cholecystokinin octapeptide and gastric bile concentration of each stress group significantly increased during the stress, while adverse effect was obtained in plasma somatostatin, which decreased from the beginning of the stress and attained the minimum nearly at the same time when the plasma cholecystokinin octapeptide concentration reached the maximum. Respective addition of cholecystokinin octapeptide and somatostatin with increasing concentrations caused rapid, sustained, concentration-dependent increase and decrease in muscle contraction of gastric antral strips, and cholecystokinin octapeptide that increased the contractile response could be blocked by respective administration of nifedipine and somatostatin significantly. Similar results were obtained in the changes of calcium fluorescence intensity and calcium currents of smooth muscle cells. Pretreatment with somatostatin significantly increased cholecystokinin octapeptide-increased phosphorylation of InsP3R3 in smooth muscle cells.

CONCLUSIONS

Gastric mucosal damage induced by bile regurgitation is closely connected with gastric antral dysmotility evoked by the changes of cholecystokinin octapeptide and somatostatin under stressful condition. Cholecystokinin octapeptide-intensified contraction depends on the release of intracellular calcium stores and the influx of extracellular calcium via L-type voltage-dependent calcium channels, while this excitatory effect of cholecystokinin octapeptide could be blocked by somatostatin, suggesting that both of the two peptides play important roles in the regulation of gastric motility.

Efficacy of a single 24-hour pre-anesthetic dose of proton pump inhibitors

BACKGROUND AND AIM

The H(2) receptor antagonist roxatidine is routinely used as an oral pre-anesthetic medication in surgical patients at night and 2 h before surgery. In the present study, we have compared the effects of roxatidine, rabeprazole and lansoprazole given singly at night as an alternative to the standard double roxatidine medication.

METHODS

120 adult patients undergoing urological surgery were randomly assigned to three groups: roxatidine, rabeprazole and lansoprazole (n = 40 each). Following induction of anesthesia, gastric fluid was obtained by aspiration using a syringe to measure pH and volume of gastric contents.

RESULTS

Gastric volume (14.1 +/- 1.9 mL) in the lansoprazole group was significantly larger than that in roxatidine (8.6 +/- 1.7 mL) and rabeprazole (7.5 +/- 1.1 mL) groups (P < 0.05). Gastric pH in lansoprazole group (4.10 +/- 0.38) was also significantly lower than that in the roxatidine group (5.41 +/- 0.31, P < 0.05). The numbers of patients with critical factors for acid aspiration pneumonia (gastric pH < 2.5 or volume > 25 mL) in the lansoprazole group was significantly higher than in the roxatidine group (P < 0.05). Gastric pH and volume in all groups were constant even in the afternoon.

CONCLUSION

Single rabeprazole (but not lansoperazole) medication may be a suitable alternative to standard roxatidine for prophylaxis of acid aspiration pneumonia.

Effects of staff training on the care of mechanically ventilated patients: a prospective cohort study

BACKGROUND

Adherence to guidelines to avoid complications associated with mechanical ventilation is often incomplete. The goal of this study was to assess whether staff training in pre-defined interventions (bundle) improves the quality of care in mechanically ventilated patients.

METHODS

This study was performed on a 50-bed intensive care unit of a tertiary care university hospital. Application of a ventilator bundle consisting of semirecumbent positioning, lung protective ventilation in patients with acute lung injury (ALI), ulcer prophylaxis, and deep vein thrombosis prophylaxis (DVTP) was assessed before and after staff training in post-surgical patients requiring mechanical ventilation for at least 24 h.

RESULTS

A total of 133 patients before and 141 patients after staff training were included. Overall bundle adherence increased from 15 to 33.8% (P<0.001). Semirecumbent position was achieved in 24.9% of patient days before and 46.9% of patient days after staff training (P<0.001). Administration of DVTP increased from 89.5 to 91.5% (P=0.048). Ulcer prophylaxis of >90% was achieved in both groups. Median tidal volume in patients with ALI remained unaltered. Days on mechanical ventilation were reduced from 6 (interquartile range 2.0-15.0) to 4 (2.0-9.0) (P=0.017). Rate of ventilator-associated pneumonia (VAP), ICU length of stay, and ICU mortality remained unaffected. In patients with VAP, the median ICU length of stay was reduced by 9 days (P=0.04).

CONCLUSIONS

Staff training by an ICU change team improved compliance to a pre-defined ventilator bundle. This led to a reduction in the days spent on mechanical ventilation, despite incomplete bundle implementation.

Gastrointestinal symptoms in intensive care patients

BACKGROUND

Gastrointestinal (GI) problems are not uniformly assessed in intensive care unit (ICU) patients and respective data in available literature are insufficient. We aimed to describe the prevalence, risk factors and importance of different GI symptoms.

METHODS

We prospectively studied all patients hospitalized to the General ICU of Tartu University Hospital in 2004-2007.

RESULTS

Of 1374 patients, 62 were excluded due to missing data. Seven hundred and seventy-five (59.1%) patients had at least one GI symptom at least during 1 day of their stay, while 475 (36.2%) suffered from more than one symptom. Absent or abnormal bowel sounds were documented in 542 patients (41.3%), vomiting/regurgitation in 501 (38.2%), high gastric aspirate volume in 298 (22.7%), diarrhoea in 184 (14.0%), bowel distension in 139 (10.6%) and GI bleeding in 97 (7.4%) patients during their ICU stay. Absent or abnormal bowel sounds and GI bleeding were associated with significantly higher mortality. The number of simultaneous GI symptoms was an independent risk factor for ICU mortality. The ICU length of stay and mortality of patients who had two or more GI symptoms simultaneously were significantly higher than in patients with a maximum of one GI symptom.

CONCLUSION

GI symptoms occur frequently in ICU patients. Absence of bowel sounds and GI bleeding are associated with impaired outcome. Prevalence of GI symptoms at the first day in ICU predicts the mortality of the patients.

Incidence and risk factors of upper gastrointestinal bleeding in mechanically ventilated children

OBJECTIVE

To identify the incidence and factors related to upper gastrointestinal (UGI) bleeding in children requiring mechanical ventilation for longer than 48 hrs.

DESIGN

Prospective analytic study.

SETTING

Ten-bed-pediatric intensive care unit of a tertiary care University Hospital.

PATIENTS

A total of 110 patients requiring mechanical ventilation for longer than 48 hrs from January 1, 2005 to December 31, 2005.

MEASUREMENTS AND RESULTS

UGI bleeding was defined by evidence of blood in nasogastric aspirates, hematemesis, or melena within 5 days of pediatric intensive care unit admission. We prospectively collected data on patient demographics, admission diagnosis, operative status, and pediatric risk of mortality score. UGI bleeding and the potential risk factors including organ failure, coagulopathy, maximum ventilator setting, enteral feeding, stress ulcer prophylaxis as well as sedation were daily monitored. Of the 110 patients who required mechanical ventilation for >48 hrs, the incidence of UGI bleeding was 51.8%, in which 3.6% of the cases presented with clinically significant bleeding (shock, requiring blood transfusion and/or surgery). Significant risk factors were thrombocytopenia, prolonged partial thromboplastin time, organ failure, high pressure ventilator setting >/=25 cm H2O, and pediatric risk of mortality score >/= 10 using univariate analysis. However, the independent factors of UGI bleeding in the multivariate analysis were organ failure (relative risk = 2.85, 95% confidence interval 1.18-6.92) and high pressure ventilator setting >/=25 cm H2O (relative risk = 3.73, 95% confidence interval 1.59-8.72).

CONCLUSION

The incidence of UGI bleeding is high in children requiring mechanical ventilation. Organ failure and high pressure ventilator setting are significant risk factors for UGI bleeding.

Altered pharmacology in the Intensive Care Unit patient

Critically ill patients, not infrequently present alterations of physiological parameters that determine the success/failure of therapeutic interventions as well as the final outcome. Sepsis and polytrauma are two of the most common and complex syndromes occurring in Intensive Care Unit (ICU) and affect drug absorption, disposition, metabolism and elimination. Pharmacological management of ICU patients requires consideration of the unique pharmacokinetics associated with these clinical conditions and the likely occurrence of drug interaction. Rational adjustment in drug choice and dosing contributes to the appropriateness of treatment of those patients.

Activation of p38 MAPK by reactive oxygen species is essential in a rat model of stress-induced gastric mucosal injury

Stress ulceration is a common complication in critically ill patients and can result in significant upper gastrointestinal bleeding associated with a high morbidity and mortality. At present, little is known of the molecular mechanisms underlying the incidence of this type of gastric damage. In the present study, we investigated the temporal activation of the redox-sensitive p38 signaling transduction cascade and its roles in a well-defined experimental model of cold immobilization stress-induced gastric ulceration. Exposure of Sprague-Dawley rats to 6 h of cold immobilization stress led to a rapid activation of p38 in the gastric mucosa at as early as 15 min after stress, and this activation was maximal after 1.5 h of stress and still persisted until the end of stress. Selectively blocking p38 by pretreatment with SB 239063, a potent and selective p38 inhibitor, suppressed the stress-promoted TNF-alpha, IL-1beta, and CINC-1 production and then prevented the subsequent neutrophil infiltration, gastric mucosal epithelial necrosis and apoptosis, and the ulcerative lesions formation. Prior administration of the free radical scavengers, tempol and N-acetyl-L-cysteine, abolished the stress induction of p38 activation and the resulting mucosal inflammation and gastric injury. These results demonstrate that reactive oxygen species-mediated p38 activation plays an essential role in the pathogenesis of stress-induced gastric inflammatory damage in the rat model of cold immobilization stress. Our findings suggested that inhibition of p38 activation might be a potential strategy for the prophylaxis and treatment of stress ulceration.

[Importance of prevention of acute mucosal lesions in patients in intensive care units]

At least three-quarters of critically ill patients develop mucosal lesion as a direct consequence of stress within the first 24 hours following the admission to intensive care unit. These mucosal lesions occur as superficial or deep mucosal lesions which can lead to massive gastrointestinal bleeding and it can put at risk the life of critically ill patient. There are multiple risk factors for the occurence of mucosal lesion such as: respiratory failure requiring mechanical ventilation, sepsis, hypotension, bums, severe trauma, neurotrauma, ileus, coagulopathy, renal and hepatic failure, myocardial infarction etc. The incidence of silent (ocult) bleeding in critically ill patients is almost 100%, but only about 5% of patients have clinically apparent (overt) hemorrhage and 1-2% have clinically significant bleeding which requires blood transfusions. In patients who are at the greatest risk of developing mucosal lesion, prophylactic treatment ought to be started immediately in order to achieve pH4 with adequate perfusion and coagulation. Today several groups of medications are used for the prevention of mucosal gastrointestinal lesion and they include: antacids, sucralfate, hisamine-2 receptor antagonists and proton pump inhibitors.

[Risk factors for bleeding from stress ulcer in severely injured and critically ill persons]

Bleeding stress ulcus is a mucosal stress induced lesion which appears as a result of mucosal damage in severely injured and critically ill persons. Prophylaxis treatment has dramatically reduced the incidence of bleeding in Intensive care units. We conducted a prospective study for the five years period. Of 954 patients (196 with acute necrotizing pancreatitis and 758 with severe injuries), 84 (8.5%) has clinically important bleeding. About 80% of these patients had more than one independent risk for acute bleeding from gastrointestinal tract. Prophylaxis treatment reduced bleeding in 90% risk patients (according Zinner score). Despite of prophylaxis, 13 patients required surgery. Overall mortality was 29 (34%) of 84 patients, including seven of 13 who required surgery. Sepsis and respiratory failure were identified as strong risk factors for bleeding in our group. The choice of the best prophylactic agens still remains the question.

Sustained activation of nuclear factor-kappaB by reactive oxygen species is involved in the pathogenesis of stress-induced gastric damage in rats

OBJECTIVE

Stress ulceration is a common complication in critically ill patients, but the mechanisms involved are poorly understood. In this study we investigated the temporal activation of the redox-sensitive transcription factor nuclear factor-kappaB and its roles in an experimental model of cold immobilization stress-induced gastric mucosal lesions.

DESIGN

Prospective, controlled, and randomized animal study.

SETTING

University research laboratory.

SUBJECTS

Male Sprague-Dawley rats.

INTERVENTIONS

The rats were subjected to cold immobilization stress for a total of 6 hrs. The temporal profiles of nuclear factor-kappaB activation and expression of tumor necrosis factor-alpha, interleukin-1beta, cytokine-induced neutrophil chemoattractant-1 (CINC-1), intercellular adhesion molecule-1 (ICAM-1), and inducible nitric oxide synthase (iNOS) were determined in the gastric corpus mucosa of stressed rats. To study the roles of nuclear factor-kappaB activation, rats received an intravenous bolus of a specific nuclear factor-kappaB inhibitor Bay 11-7082 (20 mg/kg) 1 hr before stress. For antioxidant administration, rats were treated with intravenous injection of a free radical scavenger pyrrolidine dithiocarbamate (50, 100, and 200 mg/kg) 1 hr before stress.

MEASUREMENTS AND MAIN RESULTS

Exposure of rats to 6 hrs of stress led to a rapid and persistent activation of nuclear factor-kappaB, which was associated with transient degradation of inhibitory protein IkappaBalpha and slower but sustained degradation of IkappaBbeta. Nuclear factor-kappaB activation preceded the induction of tumor necrosis factor-alpha, interleukin-1beta, CINC-1, ICAM-1, and iNOS messenger RNAs, all of which were linearly increased with the duration of stress. Bay 11-7082 selectively blocked the stress-induced nuclear factor-kappaB activation and up-regulation of tumor necrosis factor-alpha, interleukin-1beta, CINC-1, ICAM-1, and iNOS messenger RNAs. Inhibition of expression of these proinflammatory genes prevented the increases in myeloperoxidase activity (an indicator of neutrophil infiltration) in gastric mucosa and the development of gastric damage. Pyrrolidine dithiocarbamate dose-dependently inhibited the stress-induced nuclear factor-kappaB pathway activation and consequential proinflammatory gene expression, neutrophil infiltration, and gastric damage, suggesting the involvement of reactive oxygen species in these processes.

CONCLUSIONS

Sustained activation of nuclear factor-kappaB by reactive oxygen species is an important in vivo mechanism mediating stress-induced gastric inflammatory damage in rats.

Does long-term medication with a proton pump inhibitor induce a tolerance to H2 receptor antagonist?

BACKGROUND

Previous reports suggest that complete tolerance to H2 receptor antagonists (H2RAs) in patients with regular H2RA medication may be due to hypergastrinemia-increased histamine synthesis or upregulation of H2 receptors. As proton pump inhibitors (PPIs) have been reported to induce hypergastrinemia (similar to H2RAs), patients receiving long-term medication with PPIs may show tolerance to preanesthetic H2RA. Therefore, we studied the efficacy of an H2RA, roxatidine, in patients receiving long-term PPI medication.

METHODS

Effects of H2RA in 15 surgical patients receiving a regular PPI for more than 4 weeks (PPI+H2RA group) were compared with those in 30 patients not receiving regular PPIs or H2RAs (None+H2RA group and None+None group, n = 15 each). Oral roxatidine was given to both PPI+H2RA and None+H2RA group patients as an anesthetic premedication, while it was not given to None+None group patients. Gastric volume and pH were measured after induction of anesthesia.

RESULTS

Gastric pH and volume (ml) in the PPI+H2RA group (5.79 +/- 1.61 and 9.1 +/- 16.7, respectively) were both similar to those in the None+H2RA group (5.54 +/- 2.20 and 9.7 +/- 10.8, respectively) but were significantly higher (gastric pH) and lower (volume) than in the None+None group (2.29 +/- 1.84 and 29.3 +/- 22.8, respectively, P < 0.01).

CONCLUSIONS

These data suggest that long-term PPI medication may not induce a tolerance to H2RAs.

Quality Assurance Assessment of the Use of Linezolid in the Treatment of Thermal Injury Patients at a Community Teaching Hospital

We sought to evaluate the adverse effect profile of linezolid among thermal injury patients requiring treatment for Enterococcus species or other Gram-positive infection warranting treatment with linezolid. Seventy-six inhalation injury and/or thermal injury patients experiencing 94 exposures to linezolid for 48 hours or longer (range, 2-83 days) were included. We evaluated leukocyte count and platelet count for the time period preceding, during, and after therapy with linezolid based on specified time periods of exposure for evaluation of specific adverse effects. Sixty-three of 76 (83%) patient admissions were complicated by inhalation injury. The average TBSA involvement was 34.4% (range, 0-98%). The onset of thrombocytopenia before linezolid therapy was noted in 21 of 57 patients (36.8%), which was attributable to fluid resuscitation and acute platelet consumption. After they were exposure to linezolid, 12 patients developed thrombocytopenia. Platelet counts recovered in 7 of these 12 patients with continued exposure to linezolid; however, thrombocytopenia persisted for more than 9 days after therapy in 9 patients, of whom 6 patients succumbed to sepsis. On average, thrombocytes increased by 102,000/mm3 during linezolid treatment. Leucopenia was rare in thermal injury patients, and persisting thrombocytopenia in this population was associated with sepsis and mortality. Continuing linezolid therapy after the onset of thrombocytopenia among survivors almost always resulted in recovery from thrombocytopenia.

Stress ulcer prophylaxis in mechanically ventilated patients: integrating evidence and judgment using a decision analysis

OBJECTIVE

Stress ulcer prophylaxis with a histamine-2 receptor antagonist can reduce the risk of gastrointestinal bleeding in mechanically ventilated patients but may also increase the risk of ventilator-associated pneumonia. We sought to clarify the tradeoffs involved in selecting a prophylactic strategy.

DESIGN

Decision analysis.

PATIENTS AND PARTICIPANTS

A decision tree was constructed for a hypothetical cohort of patients receiving mechanical ventilation for an expected duration of longer than 48 h, using probabilities estimated from the published literature.

INTERVENTIONS

Patients in the model could receive either prophylaxis with a histamine-2 receptor antagonist or no prophylaxis. Sensitivity analyses were preformed varying the estimated probabilities over their plausible ranges.

MEASUREMENTS AND RESULTS

Both strategies were associated with approximately the same baseline expected mortality (16.6% for histamine-2 receptor antagonists and 16.9% for no prophylaxis, risk difference 0.3%). Varying the estimated probabilities resulted in only small changes in both the expected mortality and the absolute risk reduction associated with the preferred treatment. At the extremes of assumptions the absolute mortality reduction ranged from 0.1% to 3.3%.

CONCLUSIONS

No single strategy of stress ulcer prophylaxis is preferred when mortality is used as the outcome. In the absence of a clinical trial demonstrating survival benefit the individual clinician's assumptions regarding the effect of prophylaxis on gastrointestinal bleeding and pneumonia and the attributable mortality of pneumonia vs. gastrointestinal bleeding will have a significant effect on the decision.

Dynamic functional and ultrastructural changes of gastric parietal cells induced by water immersion-restraint stress in rats

AIM: To investigate the dynamic functional and ultrastructural changes of gastric parietal cells induced by water immersion-restraint stress (WRS) in rats.

METHODS: WRS model of Sprague-Dawley (SD) rats was established. Fifty-six male SD rats were randomly divided into control group, stress group and post-stress group. The stress group was divided into 1, 2 and 4 h stress subgroups. The post-stress group was divided into 24, 48 and 72 h subgroups. The pH value of gastric juice, ulcer index (UI) of gastric mucosa and H⁺, K⁺-ATPase activity of gastric parietal cells were measured. Ultrastructural change of parietal cells was observed under transmission electron microscope (TEM).

RESULTS: The pH value of gastric juice decreased time-dependently in stress group and increased in post-stress group. The H⁺, K⁺-ATPase activity of gastric parietal cells and the UI of gastric mucosa increased time-dependently in stress group and decreased in post-stress group. Compared to control group, the pH value decreased remarkably (P = 0.0001), the UI and H⁺, K⁺-ATPase activity increased significantly (P = 0.0001, P = 0.0174) in 4 h stress subgroup. UI was positively related with stress time (r = 0.9876, P < 0.01) but negatively with pH value (r = -0.8724, P < 0.05). The parietal cells became active in stress group, especially in 4 h stress subgroup, in which plenty of intracellular canalicular and mitochondria were observed under TEM. In post-stress group, the parietal cells recovered to resting state.

CONCOUSION: The acid secretion of parietal cells is consistent with their ultrastructural changes during the development and healing of stress ulcer induced by WRS and the degree of gastric mucosal lesions, suggesting gastric acid play an important role in the development of stress ulcer and is closely related with the recovery of gastric mucosal lesions induced by WRS.

Protective effect of pantoprazole on gastric mucosal lesions in rats and its mechanism

AIM: To explore the protective effect of pantoprazole on the gastric mucosal lesions in rats and its related mechanism.

METHODS: Before the gastric mucosal lesion was in-duced by pure alcohol, the rats were intravenously injected with pantoprazole (20 mg/kg), Nω-nitro-L-arginine methyl ester (L-NAME, 4 mg/kg), and L-arginine (250 mg/kg). The gastric mucosal blood flow (GMBF) was detected by laser Doppler flowmetry (LDF), and the level of NO^-₂/NO^-₃ in the gastric mucosa and serum was measured by cadmium granulation reduction and colorimetric method. The ulcer index (UI), the severity of tissue necrosis, and neutrophils infiltration were observed.

RESULTS: Compared with that in the control group, the UI was significantly decreased (5.7±2.1 vs 25.4±2.5, P <0.01), and the degrees of tissue necrosis and neutrophils infiltration were markedly lightened. The protective effect of pantoprazole was significantly decreased by L-NAME. The inhibitory effect of L-NAME was antagonized by prior administration of L-arginine. The GMBF and the content of NO^-₂/NO^-₃ in gastric mucosa and serum were increased by the intravenous administration of pantoprazole. This effect was prevented by the pretreatment of L-NAME, but the antisecretion effect of pantoprazole was not affected by L-NAME.

CONCLUSION: Pantoprazole can protect gastric muc-osa against the lesions in rats by the mediation of nitric oxide (NO), and the protective effect has no relation with its antisecretory action of gastric acid.

Gastric juice: a barrier against infectious diseases

All vertebrates produce gastric acid. Its main function is inactivation of ingested microorganisms. The majority of microbiological pathogens ingested never reaches the intestine because of the gastric barrier. Although gastric hypochlorhydria is fairly common due to atrophic gastritis, gastric surgery or use of inhibitors of gastric acid secretion, the resulting susceptibility to infection has not been studied extensively. Drug-induced blockade of acid secretion leads to gastrointestinal bacterial overgrowth; the clinical significance of this is still controversial. Gastric acidity is known to protect against non-typhoid salmonellosis and cholera and it is suspected that it protects against several parasitic diseases as giardiasis and strongyloides. There is a lack of studies focusing on the impact of the gastric acidic barrier on viral infections. Concerning prion infections only a single study has been performed, demonstrating a possible role of gastric acidity in the protection against foodborne prion disease in mice. The combination of malnutrition and hypochlorhydria may contribute to the high prevalence of gastrointestinal infections in developing countries. Further studies are needed to evaluate the clinical consequences of impaired gastric acidity with respect to susceptibility to infections.

The Efficacy of Preanesthetic Proton Pump Inhibitor Treatment for Patients on Long-Term H2 Antagonist Therapy

We previously reported that H2-antagonist medication given for longer than 4 wk may produce complete tolerance to preanesthetic H2 antagonist therapy. In this study, we evaluated the efficacy of preanesthetic proton pump inhibitor (PPI; oral rabeprazol) use in patients receiving regular H2-antagonist (oral famotidine) therapy for more than 4 wk. Forty-eight patients with assumed complete tolerance to H2 antagonists undergoing elective surgery were recruited and randomly assigned to receive either a preanesthetic PPI (rabeprazol 20 mg; n = 24) or H2-antagonist (H2 group; roxatidine 75 mg; n = 24) at 9:00 pm on the day before surgery and 2 h before the induction of anesthesia. Volume of gastric contents and pH values were measured after the induction of anesthesia. Gastric pH value in the PPI group (5.38 +/- 2.42) was significantly higher than in the H2 group (3.27 +/- 1.98; P < 0.01). Gastric volume in the PPI group (8.6 +/- 1.5 mL) was significantly smaller than in the H2 group (15.4 +/- 2.8 mL; P < 0.05; cf. PPI). Fourteen patients in the H2 group were at risk of acid aspiration pneumonia (gastric pH <2.5 or volume >25 mL), whereas only four patients in the PPI group (P < 0.05) were at risk. These data suggest that in patients receiving H2-antagonist therapy for longer than 4 wk, prophylaxis for acid aspiration pneumonia should include preanesthetic PPI medication.

IMPLICATIONS

We previously reported that more than 4 wk of administration of H2-antagonists may produce a full tolerance to preanesthetic H2-antagonists. The present study suggests that a proton pump inhibitor may be effective for prophylaxis of acid aspiration pneumonia in patients showing the full tolerance to H2 antagonists.

The Role of Proton Pump Inhibitors in Acute Stress Ulcer Prophylaxis in Mechanically Ventilated Patients

This article reviews the use of proton pump inhibitors, other pharmacological therapies, and nonpharmacological therapies for the prevention of acute stress ulcers in critically ill patients.

Randomized, double-blind comparison of immediate-release omeprazole oral suspension versus intravenous cimetidine for the prevention of upper gastrointestinal bleeding in critically ill patients

OBJECTIVE

To demonstrate that a new immediate-release omeprazole oral suspension is effective in preventing upper gastrointestinal bleeding in critically ill patients.

DESIGN

A noninferiority analysis was used to compare rates of clinically significant upper gastrointestinal bleeding in a prospective, phase 3, double-blind trial with parallel omeprazole suspension and cimetidine treatment groups.

SETTING

A total of 47 intensive care units in the United States.

PATIENTS

A total of 359 critically ill patients who required mechanical ventilation for > or =48 hrs, had an Acute Physiology and Chronic Health Evaluation score of > or =11 at baseline, had an intact stomach with a nasogastric or orogastric tube in place, and had at least one additional risk factor for upper gastrointestinal bleeding.

INTERVENTIONS

Patients were randomized to treatment with omeprazole suspension (two 40-mg doses on day 1, via orogastric or nasogastric tube, and 40 mg each day thereafter) or intravenous cimetidine (300-mg bolus and 50 mg/hr thereafter) for up to 14 days. Gastric aspirates were sampled for bleeding and pH. Medication doses were doubled for failure of pH control (two successive aspirates with pH < or = 4).

MEASUREMENTS AND MAIN RESULTS

Clinically significant upper gastrointestinal bleeding (bright red blood not clearing after 5-10 mins of lavage or persistent Gastroccult-positive "coffee-grounds" material for 8 hrs on days 1-2 or for 2-4 hrs on days 3-14 and not clearing with > or =100 mL of lavage) was the primary end point of the trial. The rate of clinically significant bleeding in the per-protocol population was 4.5% with omeprazole suspension and 6.8% with cimetidine, meeting the criteria for the noninferiority of omeprazole suspension. Median gastric pH was > or =6 on all trial days with omeprazole suspension treatment and on 50% of days with cimetidine treatment (p < .001, all trial days). In the omeprazole suspension group, median gastric pH was >4 on each trial day in 95% of patients.

CONCLUSIONS

Immediate-release omeprazole suspension is effective in preventing upper gastrointestinal bleeding and more effective than intravenous cimetidine in maintaining gastric pH of >4 in critically ill patients.

Role of capsaicin-sensitive nerves and histamine H1, H2, and H3 receptors in the gastroprotective effect of histamine against stress ulcers in rats

It is assumed that an overproduction of gastric acid is the most important factor in the development of peptic ulcer. However, it has been also demonstrated that gastric defense mechanisms, which prevent mucosal injury, are enhanced by the same factors that increase acid secretion. The aim of this study was to examine the role of capsaicin-sensitive sensory nerves and histamine H1, H2, and H3 receptors in histamine-induced gastroprotection against stress ulcers. Studies were performed on rats with intact or ablated sensory nerves. Ablation of sensory nerves was induced by neurotoxic doses of capsaicin. Gastric ulcers were induced by water immersion and restrain stress. Before exposure to stress, rats were pretreated with saline (control), histamine (10 micromol/kg), histamine H1 receptor antagonist pyrilamine (100 micromol/kg), histamine H2 receptor antagonist ranitidine (100 micromol/kg), histamine H3 receptor antagonist thioperamide (100 micromol/kg), or a combination of histamine with these histamine receptor antagonists.

RESULTS

Histamine alone reduced ulcer area evoked by stress and this effect was accompanied by an increase in gastric mucosal blood flow and mucosal DNA synthesis, as well as a decrease in serum pro-inflammatory interleukin-1beta concentration. Treatment with combination of pyrilamine plus histamine caused an increase in gastric ulcer area and serum interleukin-1beta above the value observed in animals treated with saline, and this effect was accompanied by a decrease in gastric mucosal DNA synthesis. Ranitidine, in combination with histamine, reduced the ulcer area and serum interleukin-1beta to a minimal value, whereas gastric mucosal blood flow and DNA synthesis reached a maximal value. Pretreatment with thioperamide before histamine administration abolished the histamine-evoked reduction in gastric ulcer area. Ablation of sensory nerves increased the ulcer area in animals treated with saline or histamine, or histamine in combination with pyrilamine or ranitidine. In animals with sensory nerves ablation combined with administration of thioperamide plus histamine, the ulcer area was similar to that in saline-treated animals with intact sensory nerves. We conclude that: (1) histamine exhibits protective effect against stress-induced gastric ulcer and that this gastroprotection is related to stimulation of histamine H1 and H3 receptors; (2) blockade of histamine H2 receptors exhibited beneficial effect on gastric mucosa against stress-induced gastric ulcers; and (3) ablation of sensory nerves aggravates stress-induced gastric ulcer and reduces histamine-evoked gastroprotection related to stimulation of histamine H3 receptors.