Continuous pralidoxime infusion versus repeated bolus injection to treat organophosphorus pesticide poisoning: a randomised controlled trial. Pralidoxime in acute organophosphorus insecticide poisoning--a randomised controlled trial. Optimal dose of intravenous pantoprazole in patients with peptic ulcer bleeding requiring endoscopic hemostasis in Korea. Can remifentanil be a better choice than propofol for colonoscopy during monitored anesthesia care?
The role of oximes for the treatment of organophosphorus pesticide poisoning has not been conclusively established. We aimed to assess the effectiveness of a constant pralidoxime infusion compared with repeated bolus doses to treat patients with moderately severe poisoning from organophosphorus pesticides.
                200 patients were recruited to our single-centre, open randomised controlled trial after moderately severe poisoning by anticholinesterase pesticide. All were given a 2 g loading dose of pralidoxime over 30 min. Patients were then randomly assigned to control and study groups. Controls were given a bolus dose of 1 g pralidoxime over 1 h every 4 h for 48 h. The study group had a constant infusion of 1 g over an hour every hour for 48 h. Thereafter, all patients were given 1 g every 4 h until they could be weaned from ventilators. Analysis was by intention to treat. Primary outcome measures were median atropine dose needed within 24 h, proportion of patients who needed intubation, and number of days on ventilation. The study is registered at http://www.clinicaltrials.gov with the identifier NCT00333944.
                100 patients were assigned the high-dose regimen, and 100 the control regimen. There were no drop-outs. Patients receiving the high-dose pralidoxime regimen required less atropine during the first 24 h than controls (median 6 mg vs 30 mg; difference 24 mg [95% CI 24-26, p<0.0001]). 88 (88%) and 64 (64%) of controls and high-dose patients, respectively, needed intubation during admission to hospital (relative risk=0.72, 0.62-0.86, p=0.0001). Control patients required ventilatory support for longer (median 10 days vs 5 days; difference 5 days [5-6, p<0.0001]).
                A high-dose regimen of pralidoxime, consisting of a constant infusion of 1 g/h for 48 h after a 2 g loading dose, reduces morbidity and mortality in moderately severe cases of acute organophosphorus-pesticide poisoning. Poisoning with organophosphorus (OP) insecticides is a major global public health problem, causing an estimated 200,000 deaths each year. Although the World Health Organization recommends use of pralidoxime, this antidote's effectiveness remains unclear. We aimed to determine whether the addition of pralidoxime chloride to atropine and supportive care offers benefit.
                We performed a double-blind randomised placebo-controlled trial of pralidoxime chloride (2 g loading dose over 20 min, followed by a constant infusion of 0.5 g/h for up to 7 d) versus saline in patients with organophosphorus insecticide self-poisoning. Mortality was the primary outcome; secondary outcomes included intubation, duration of intubation, and time to death. We measured baseline markers of exposure and pharmacodynamic markers of response to aid interpretation of clinical outcomes. Two hundred thirty-five patients were randomised to receive pralidoxime (121) or saline placebo (114). Pralidoxime produced substantial and moderate red cell acetylcholinesterase reactivation in patients poisoned by diethyl and dimethyl compounds, respectively. Mortality was nonsignificantly higher in patients receiving pralidoxime: 30/121 (24.8%) receiving pralidoxime died, compared with 18/114 (15.8%) receiving placebo (adjusted hazard ratio [HR] 1.69, 95% confidence interval [CI] 0.88-3.26, p = 0.12). Incorporating the baseline amount of acetylcholinesterase already aged and plasma OP concentration into the analysis increased the HR for patients receiving pralidoxime compared to placebo, further decreasing the likelihood that pralidoxime is beneficial. The need for intubation was similar in both groups (pralidoxime 26/121 [21.5%], placebo 24/114 [21.1%], adjusted HR 1.27 [95% CI 0.71-2.29]). To reduce confounding due to ingestion of different insecticides, we further analysed patients with confirmed chlorpyrifos or dimethoate poisoning alone, finding no evidence of benefit.
                Despite clear reactivation of red cell acetylcholinesterase in diethyl organophosphorus pesticide poisoned patients, we found no evidence that this regimen improves survival or reduces need for intubation in patients with organophosphorus insecticide poisoning. The reason for this failure to benefit patients was not apparent. Further studies of different dose regimens or different oximes are required. The lowest effective dose of proton pump inhibitors (PPI) for prevention of peptic ulcer rebleeding remains unclear. The objective of the present study was to evaluate whether low-dose PPI has a similar efficacy to high-dose i.v. administration for maintaining intragastric pH above 6.
                Sixty-one patients with bleeding ulcers were randomized into one of three groups after endoscopic hemostasis: pantoprazole 80 mg bolus followed by 8 mg/h; 40 mg, 4 mg/h infusion; and bolus injection of 40 mg every 24 h. Intragastric pH values and rebleeding rates were measured. In addition, pharmacokinetic parameters and association with CYP2C19 polymorphisms and H. pylori infection were assessed.
                Mean percentage of time with intragastric pH > 6, and the proportion of patients with pH > 6 for more than 60% of the time were significantly higher in the 40 mg, 4 mg/h infusion group compared to the 40 mg bolus injection. There was no significant difference between the 80 mg, 8 mg/h and the 40 mg, 4 mg/h groups. In the H. pylori (-) group, only 40% of patients that received continuous infusion reached the target pH > 6 for more than 60% of the time; this was significantly lower than the H. pylori (+) group, 87.5% (P = 0.026).
                A continuous infusion, regardless of high or low dose, was more effective for acid suppression than a 40 mg bolus PPI injection in Korea. H. pylori infection was an important factor for the maintenance of an intragastric pH > 6. This prospective, randomized trial was designed to test the hypothesis that continuous infusion of low-dose remifentanil can provide effective analgesia, sedation, amnesia, patient comfort and stable recovery profile without respiratory depression when compared with propofol infusion during colonoscopy.
                One hundred patients were randomly assigned to receive either remifentanil (group R, 0.5 microg/kg followed by 0.05 microg/kg/min, n = 50) or propofol (group P, 0.5 mg/kg followed by 50 microg/kg/min, n = 50). Supplemental doses of remifentanil 12.5 microg in group R and propofol 10 mg in group P were given to treat complaints of moderate to severe pain and discomfort. Hemodynamic and respiratory data, pain, discomfort and sedation scores, patient and gastroenterologist satisfaction and recovery profiles were recorded.
                The duration of colonoscopy was longer in group P. The mean arterial pressure, heart rate and end-tidal CO2 remained stable during the procedure and were comparable between the groups. After bolus injection of the study drugs, the respiratory rate and oxygen saturation values were lower in group R than in group P. Only one patient in group R required airway support. Pain and discomfort scores were better in group R than in group P. Sedation levels were higher in group P than in group R. Group P needed more supplemental doses than group R. The time to reach an Aldrete score of nine or more was shorter in group R, but discharge times were similar in the two groups. Amnesia was better in group P. Nausea and vomiting were more frequent in group R during the recovery phase.
                Low-dose remifentanil infusion with intermittent bolus injections can provide adequate sedation, amnesia and better analgesia than propofol infusion during colonoscopy. However, remifentanil-induced nausea and vomiting may be a problem during the recovery phase.
Current evidence is insufficient to indicate whether oximes are harmful or beneficial. The WHO recommended regimen (30 mg/kg pralidoxime chloride bolus followed by 8 mg/kg/hr infusion) is not supported. Further RCTs are required to examine other strategies and regimens. There are many theoretical and practical reasons why oximes may not be useful, particularly for late presentations of dimethyl OP and those with a large excess of OP that simply re-inhibits reactivated enzymes. Future studies should screen for patient sub-groups that may benefit and may need flexible dosing strategies as clinical effectiveness and doses may depend on the type of OP.