Effects of atropine sulfate and neostigmine on gastric electrical activity in human subjects--electrogastrographic study.

BACKGROUND/AIMS: There are few reports about the cholinergic regulation of gastric electrical activities using percutaneous electrogastrograms (EGG). To determine the effect of intravenous administration of a vagal blocker (atropine sulfate) or a vagal stimulator (neostigmine) on gastric electrical activities EGG was utilized in this study. METHODOLOGY: EGG was recorded before and after administration of a vagal blocker (atropine sulfate, 0.02mg/kg) and/or vagal stimulator (neostigmine, 0.008mg/kg) in six normal volunteers. RESULTS: After administration of atropine sulfate, the original waves on EGG almost disappearedand decreased amplitudes were detected by visual inspection in all subjects. Moreover, increase amplitude on EGG was clearly demonstrated after administration of neostigmine in all subjects. It was also shown that the effects of these medicines persisted more than 60 minutes after injection. CONCLUSIONS: These findings suggest that the EGG reflected gastric motility, and that neurological regulation of EGG was mediated through the vagal and/or cholinergic efferent pathway.

[Current status of pulmonary aspiration associated with general anesthesia: a nationwide survey in Japan].

BACKGROUND: Aspiration has been considered as a morbid complication of anesthesia. The current status of anesthesia-associated pulmonary aspiration, however, has not yet been assessed in modern Japanese anesthesia practices. METHODS: A written questionnaire was sent to all of the Japanese anesthesia-teaching hospitals certified by the Japan Society of Anesthesiologists and 56% of questionnaires were recovered and analyzed. RESULTS: In the year 2002, 58 cases of pulmonary aspiration were reported (approximately 0.8/ 10,000 anesthesia cases). Approximately one-third of patients with aspiration subsequently suffered severe pulmonary complications necessitating mechanical ventilation and/or admission to the intensive care unit. Mortality in patients with aspiration was 5% (3/57; 1/250,000 anesthesia cases). Predisposing factors of emergency abdominal surgery with bowel obstruction, but not short fasting period, appeared to be associated with occurrence of severe pulmonary aspiration. Unproven therapies for aspiration were frequently applied, including bronchial toileting, systemic high-dose steroids and prophylactic antibiotics. CONCLUSIONS: Aspiration remains a significant complication, even in modern anesthesia practices. Given the high morbidity and few proven therapies, nationwide clinical trials should be conducted and national therapeutic guidelines should be established in Japan.

Current practice of preoperative fasting: a nationwide survey in Japanese anesthesia-teaching hospitals.

PURPOSE: We conducted a nationwide survey to investigate the current practice of the preoperative fasting period in Japanese anesthesia-teaching hospitals. Acceptance of the clinical practice guideline published by the American Society of Anesthesiologists (ASA) was also surveyed. METHODS: A written type of questionnaire was mailed to 795 teaching hospitals. RESULTS: The response rate of the questionnaires was 57%. Most (>90%) of the respondents had been applying a longer fasting period than the ASA-recommended minimum period specifically in adults; the median duration of fasting was 12-13 h for solids and 6-9 h for liquids. Children or infants were allowed a more liberalized fasting period, frequently being permitted an oral intake of clear fluids up to 3 h before anesthesia. The incidence of pulmonary aspiration was 1/12,500 general anesthesia cases, and application of the ASA guideline appeared not to affect the incidence. Japanese anesthesiologists were still reluctant to depart from their traditional long fasting periods, as most of them could find little benefit in reducing the fasting periods. CONCLUSION: The long preoperative fasting period is still common practice in Japanese anesthesia-teaching hospitals. A national guideline for a preoperative fasting policy is worth exploring to change the current practice.

Bioelectrical impedance analysis for assessment of severity of illness in pediatric patients after heart surgery.

OBJECTIVE: To investigate whether perioperative changes in bioelectrical impedance reflect the severity of illness in pediatric patients after heart surgery. DESIGN: Prospective, controlled study. SETTING: University-affiliated children's hospital. PATIENTS: A total of 107 patients admitted to a pediatric intensive care unit after congenital heart surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Single frequency (50 kHz) bioelectrical impedance was measured in the lower extremities before surgery and immediately, 16 hrs, and 40 hrs after admission (D0, D1, D2) to the pediatric intensive care unit. Postoperative changes in bioelectrical impedance were assessed by calculating values relative to the preoperative data (bioelectrical impedance ratio). These bioelectrical impedance ratios at D0 in both the nonsurviving and surviving patients were 0.84 +/- 0.06 and 0.85 +/- 0.01 (mean +/- SE), respectively, indicating that the initial decrease caused by surgical stress itself was not directly related to the prognosis. The bioelectrical impedance ratio showed an increase toward preoperative values in surviving patients (0.94 +/- 0.02) at D1, and they showed a sustained decrease (0.70 +/- 0.06) in nonsurviving patients. Patients with a bioelectrical impedance ratio at D1 of < 0.8 showed a higher mortality (25%) compared with those patients with a day-1 bioelectrical impedance ratio of > or = 1.0 (0%). The duration of the stay in the pediatric intensive care unit, mechanical ventilation, and inotropic support were all significantly longer in the patients with the lower bioelectrical impedance ratio. CONCLUSIONS: Measurement of the relative changes in postoperative bioelectrical impedance, which reflects perioperative alterations in body composition, provides a quantitative estimation of the critical illness in pediatric patients after heart surgery.

Comparative effects of nitroglycerin on intestinal vascular capacitance and conductance.

BACKGROUND: Nitroglycerin (NTG) dilates capacitance veins and resistance arterioles, but its relative effects on veins and arterioles are not known. OBJECTIVES: To compare NTG-induced changes in capacitance and conductance. ANIMALS AND METHODS: Aortic, left ventricular and portal venous (P(port)) pressures, portal flow and relative changes in intestinal blood volume (IBV) ((99m)technetium blood-pool scintigraphy) were measured in seven isoflurane-anesthetized, splenectomized dogs. Changes in intestinal vascular capacitance and conductance (mean portal flow/[mean aortic pressure - mean P(port)]) were determined when NTG was continuously administered (0.8 to 150 microg/kg/min) into a jugular vein. Pressure-volume (ie, P(port)-IBV) curves were defined by impeding portal flow, and capacitance was defined as the IBV at P(port)=7.5 mmHg. RESULTS: At lower doses, NTG increased capacitance without increasing conductance, but conductance increased considerably with little further increase in capacitance at higher doses. Dose-response analysis revealed that the half-maximum capacitance effect was achieved at an NTG infusion rate of 3.5 microg/kg/min, whereas a rate of 35 microg/kg/min was required for the half-maximum conductance effect. CONCLUSIONS: At lower doses, NTG dilates capacitance vessels primarily, and that effect approaches its maximum before significant dilation of conductance vessels is manifest. However, at higher doses, the increase in conductance is substantial with little additional effect on capacitance.