Search PubMed⌕ Search

Biomedical subjects

K Mikawa

Publications and source records attributed to K Mikawa.

At least 127 records · Page 7Linked to original sources
PubMed1993

Attenuation of the pressor response to tracheal intubation with oral nitrendipine.

The effect of nitrendipine on the cardiovascular responses to tracheal intubation was studied in a placebo-controlled, randomised, double-blind trial. Thirty patients (ASA physical status 1) undergoing elective surgery received either 5 or 10 mg nitrendipine, or a placebo orally 3 h before induction of anaesthesia (n = 10 for each group). Anaesthesia was induced with sodium thiopentone 5 mg/kg i.v. and tracheal intubation was facilitated with vecuronium 0.2 mg/kg i.v. Patients receiving the placebo showed a significant increase in the mean arterial pressure and the rate-pressure product in response to tracheal intubation. These increases following intubation were reduced in nitrendipine-treated patients compared with the placebo group (P < 0.05). Oral administration of nitrendipine (5 or 10 mg, 3 h before induction of anaesthesia) was able to attenuate the hypertensive response to tracheal intubation in ASA 1 patients under light anaesthesia. We propose this pharmacological technique with supplementary doses of opioids and/or benzodiazepines for the management of patients with hypertension or coronary artery disease.

Administration, Oral↗
PubMed1993

Effects of 2-, 4- and 12-hour fasting intervals on preoperative gastric fluid pH and volume, and plasma glucose and lipid homeostasis in children.

We evaluated 105 randomly-selected unpremedicated children aged 1-14 years to determine the effects of a 2-, 4- and 12-h preoperative fasting interval on the preoperative gastric fluid pH and volume, and plasma glucose and lipid homeostasis. Each child undergoing elective surgery ingested a large volume (approximately 10 ml/kg b.w.) of apple juice and then fasted for 2, 4 or 12 h before the estimated induction of anaesthesia. After induction of anaesthesia, gastric fluid was aspirated through a large-bore, multiorifice orogastric tube. Plasma concentrations of glucose, total ketone bodies, non-esterified fatty acid (NEFA), triglycerides, and cortisol were measured at the time of induction to evaluate the fasting interval effects on preoperative plasma glucose and lipid homeostasis. There were no significant differences between the three groups in either gastric fluid volume or pH. In addition, there were no significant differences between the groups with respect to the proportion with a pH < 2.5 and volume > 0.4 ml/kg b.w. Neither plasma concentrations of glucose, triglycerides, nor cortisol at the time of anaesthetic induction differed between the three groups. Both 4 and 12 h nil per os (NPO) caused an increase in lipolysis, which was presumably a compensatory mechanism to maintain normoglycaemia. The plasma NEFA and total ketone bodies concentrations were therefore significantly higher in these two fasting intervals than in 2 h NPO. These data suggest that a 2-h NPO, after a large volume of ingested apple juice, may offer additional benefits by preventing an increase in lipolysis during the fasting interval without either increasing the volume of gastric fluid or decreasing the gastric pH.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Effect of reduced alcohol consumption on blood pressure in untreated hypertensive men.

Fifty-four untreated, mildly hypertensive men whose daily alcohol consumption was > or = 28 ml ethanol and who drank at least 4 times per week took part in a randomized, controlled crossover trial. The purpose of the trial was to test the effects of alcohol reduction on blood pressure. After a 2-week familiarization period, the participants were assigned to either a reduced alcohol drinking group or a usual drinking group for 3 weeks (experimental period 1). The situation was then reversed for the next 3 weeks (experimental period 2). The participants were requested to limit their daily alcohol consumption to zero or reduce it as much as possible for the reduced alcohol consumption period. The self-reported alcohol consumption was 56.1 +/- 3.6 (SEM) ml/day during the usual alcohol drinking period and 26.1 +/- 3.0 ml/day during the period of reduced alcohol consumption. Systolic and diastolic blood pressures in the intervention group were found by analysis of variance to be significantly lower (2.6-4.8 and 2.2-3.0 mm Hg, respectively) than those in the control group during experimental period 2 for systolic blood pressure and experimental period 1 for diastolic blood pressure. Significant (3.6 mm Hg) and nonsignificant (1.9 mm Hg) decreases in systolic and diastolic blood pressure, respectively, were observed. The method of Hills and Armitage was used, reducing ethanol in daily alcohol consumption by 28 ml. The lowering effect of reduced alcohol consumption on blood pressure was independent of changes in salt consumption, which were estimated by 24-hour urine collection and body weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Attenuation of the cardiovascular and catecholamine responses to tracheal intubation with oral guanabenz.

We conducted a randomized, placebo-controlled, and double-blind study to evaluate the efficacy of oral guanabenz, an alpha 2-adrenergic agonist, in attenuating the cardiovascular and catecholamine responses to laryngoscopy and tracheal intubation in 30 normotensive (ASA physical status 1) patients undergoing elective surgery. They were allocated to one of three groups (n = 10 for each): placebo, 4 mg, or 6 mg of guanabenz groups. These tablets were administered 2 h before the induction of anesthesia. Anesthesia was induced with thiopental 5.0 mg/kg intravenously (IV), and tracheal intubation was facilitated by the administration of vecuronium, 0.2 mg/kg IV. During anesthesia, ventilation was assisted or controlled with 1% enflurane and 50% nitrous oxide in oxygen. Laryngoscopy lasting 30 s was attempted 2 min after the administration of thiopental and vecuronium. Patients receiving placebo showed a significant increase in mean arterial blood pressure, heart rate, and plasma catecholamine concentrations in response to tracheal intubation. These changes were significantly smaller in patients receiving either dose of guanabenz (P < 0.05). Oral administration of guanabenz before induction of anesthesia is a simple and effective method for attenuating the pressor and tachycardic responses to laryngoscopy and tracheal intubation with the drug acting at least partly via inhibition of the increases in plasma catecholamines concentrations.

Administration, Oral↗
PubMed1993

Influence of milk proteins on the thermostability of the lipase from Pseudomonas fluorescens 33.

The effects of some milk proteins on the thermostability of the lipase from Pseudomonas fluorescens 33 were investigated. All purified milk protein fractions except kappa-casein that dissolved in phosphate buffer were effective for thermostabilization of the lipase. Thermal behavior of the lipase containing beta-lactoglobulin was so specific that, after heating at 80 to 90 degrees C, activity remained high and was comparable with that of unheated treatment. The thermostability of the lipase containing whey proteins in synthetic salts solution was extensively lowered, but that containing casein micelles retained 50% of original activity after heat treatment at 80 degrees C for 10 min. Low temperature inactivation of the lipase was influenced by concomitant milk proteins.

Caseins↗
PubMed1993

Selective intrabronchial instillation of surfactant in a patient with pneumonia: a preliminary report.

The efficacy of treatment with exogenous surfactant has been reported in children with respiratory failure due to severe pneumonia. Its effect in adults with similar features has not been established. We therefore administered 240 mg of surfactant to a 71 year old man, who had developed right lower lobe pneumonia and hypoxaemia following abdominal aortic surgery. After this treatment, the patient's oxygenation, evaluated by arterial oxygen tension/fraction of inspired oxygen (PaO2/FIO2) ratio during artificial ventilation, gradually improved, and ventilator settings could be reduced whilst maintaining PaO2 at the appropriate level. Although the precise mechanism by which surfactant improves respiratory failure due to pneumonia is unclear, administration of the drug may have overcome a quantitative deficiency of endogenous surfactant attributable to the antagonistic effect of pulmonary exudates and reduced production following damage to type II pneumocytes. The present case provides an indirect suggestion of a possible causal relationship between the improvement of oxygenation and administration of surfactant in adult respiratory failure caused by pneumonia.

Aged↗
PubMed1992

Effect of verapamil on the cardiovascular responses to tracheal intubation.

We have studied the efficacy of verapamil in attenuating the cardiovascular responses to tracheal intubation in three groups of ASA grade I patients given verapamil 0.05 mg kg-1 or 0.1 mg kg-1 or saline 45 s before the start of laryngoscopy. Anaesthesia was induced with thiopentone 5 mg kg-1 i.v. and tracheal intubation was facilitated with vecuronium 0.2 mg kg-1. During anaesthesia, ventilation was assisted or controlled with 1% enflurane and 50% nitrous oxide in oxygen. In patients who received saline, there was a significant increase in mean arterial pressure and rate-pressure product associated with tracheal intubation. The increases were significantly less in verapamil-treated patients compared with those in the control group, although verapamil failed to prevent tachycardia caused by laryngoscopy and intubation.

Adult↗
PubMed1992

Perioperative complement activation in neonates under halothane or fentanyl anaesthesia.

We investigated perioperative changes in complement activation in 18 neonates undergoing elective abdominal surgery with or without thoracotomy by measuring plasma concentrations of C3a and C5a, and leucocyte counts in peripheral blood. The 18 neonates, ranging in age from 1 to 17 days, were randomly divided into two groups according to type of anaesthetic procedures; the "halothane group" consisted of nine neonates in whom general anaesthesia was maintained with halothane and nitrous oxide (N2O) in oxygen, while the "fentanyl group" consisted of nine neonates in whom general anaesthesia was maintained with fentanyl and N2O in oxygen. Plasma C3a and C5a concentrations were higher in the fentanyl group than in the halothane group during the perioperative period. We have demonstrated that abdominal surgical trauma caused complement activation even in neonates undergoing the fentanyl rather than the halothane anaesthesia. Further studies are required to elucidate the precise mechanisms and the clinical implication of perioperative complement activation in neonates.

Abdomen↗
PubMed1992

Effects of mexiletine on the haemodynamic responses to tracheal intubation.

The efficacy of intravenous mexiletine in attenuating the cardiovascular responses to laryngoscopy and tracheal intubation was studied in 30 normotensive patients undergoing elective surgery. The patients were randomly allocated to one of three treatment groups: saline (n = 10); 2 mg/kg mexiletine (n = 10); and 3 mg/kg mexiletine (n = 10). The placebo/mexiletine was administered immediately before induction of anaesthesia using 5 mg/kg thiopentone and tracheal intubation was facilitated with 0.2 mg/kg vecuronium; laryngoscopy lasting 30 s was attempted 2 min after induction of anaesthesia. All groups showed a significant (P less than 0.05) increase in mean arterial pressure and heart rate associated with tracheal intubation. The increase in mean arterial pressure was significantly (P less than 0.05) smaller in patients receiving 3 mg/kg mexiletine compared with those receiving either saline or 2 mg/kg mexiletine. There was no significant attenuation in heart rate in either of the mexiletine treatment groups compared with the saline group. It is concluded that 3 mg/kg mexiletine given intravenously provides a simple and effective method for attenuating the pressor response to laryngoscopy and tracheal intubation.

Adult↗
PubMed1992

[Coronary artery spasm during coronary artery bypass surgery].

We report two cases of coronary artery spasm during coronary artery bypass surgery. As one of the complications during cardiac surgeries, coronary vasoconstriction occurs mainly after coming off cardiopulmonary bypass. The factors responsible for the spasm include high endogenous catecholamine levels due to inadequate anesthesia and hypothermia, exogenous catecholamines for circulatory support, various chemical mediators and combination of these factors. Coronary artery spasm was suspected strongly because of sudden ischemic change in electrocardiography and simultaneous aggravation of circulatory parameters, which improved immediately after direct injection of coronary vasodilators into vein graft. This method, popular in coronary angiography and catheterization, is effective for release of coronary-artery spasm observed particularly after cardiopulmonary bypass. Then mechanical circulatory assist is readily available to treat possible systemic side effect of the vasodilators.

Coronary Artery Bypass↗
PubMed1991

Effects of trimetaphan on the cardiovascular response to tracheal intubation.

In three groups of 10 patients, we have studied the effect on the cardiovascular responses to laryngoscopy and intubation of bolus doses of saline or trimetaphan 0.05 mg kg-1 or 0.1 mg kg-1 given 1.75 min before the start of laryngoscopy. Anaesthesia was induced with thiopentone 5 mg kg-1 i.v. and tracheal intubation was facilitated with vecuronium 0.2 mg kg-1. During anaesthesia, ventilation was assisted or controlled with 1% enflurane and 50% nitrous oxide in oxygen. Patients receiving saline showed a significant increase in mean arterial pressure and rate-pressure product associated with tracheal intubation. These increases following tracheal intubation were less in trimetaphan-treated patients compared with those of the control group (P less than 0.05). There was no significant difference in heart rate following tracheal intubation between the three groups. These data suggest that trimetaphan may be used as a supplement during induction, to attenuate the hypertensive response associated with laryngoscopy and tracheal intubation.

Anesthesia, General↗