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Biomedical subjects

P Viars

Publications and source records attributed to P Viars.

At least 199 records · Page 11Linked to original sources
PubMed1983

[Acute postoperative pulmonary edema in the coronary patient: effects of myocardial ischemia].

In order to evaluate the incidence of myocardial ischaemia in patients who developed acute pulmonary oedema during the immediate post-operative period, continuous monitoring of the electrocardiogram by the Holter method was used in 200 consecutive patients with coronary artery disease. Fourteen of these patients exhibited ST segment depression during the post-operative period and 13 during surgery. Nine patients developed acute pulmonary oedema immediately after the operation and in 7 cases the oedema was preceded by myocardial ischaemia. A continuous nitroglycerin infusion brought about regression of the pulmonary oedema in 8 cases. One patient died despite treatment. These findings underline the part played by myocardial ischaemia in the pathogenesis of acute post-operative pulmonary oedema in patients with coronary artery disease.

Acute Disease↗
PubMed1983

[Determination of the dose-effect curve of vecuronium in anesthetized man].

Dose-response curves have been determined in 37 healthy subjects, after injection of a single bolus of Organon NC 45 (vecuronium or Norcuron). The doses used were 0.0125, 0.025, 0.037 and 0.05 mg X kg-1. The ulnar nerve was stimulated at the wrist and the force of thumb adduction measured. No premedication was used. Anesthesia was induced with thiopentone and fentanyl, and maintained by a nitrous oxide/oxygen mixture under controlled ventilation. PaCO2 was 37 +/- 0.5 mmHg and temperature 36.8 +/- 0.1 degrees C. The effective doses (ED) were: ED50 at 0.024 mg X kg-1, ED90 at 0.034 mg X kg-1 and ED95 at 0.037 mg X kg-1. At 0.05 mg X kg-1, the degree of twitch inhibition was 99.2 +/- 0.6%, the delay of maximum effect was 7.7 +/- 1.4 min, and the length of action (up to 90% recovery) was 27.2 +/- 2.3 min. Vecuronium is therefore a potent neuromuscular blocking agent with a relatively short duration of action.

Adolescent↗
PubMed1983

[Hemodynamic effects of vecuronium in man].

The cardiovascular effects of vecuronium (Organon NC 45 or Norcuron) in man were determined through different protocols using continuous recording of heart rate, arterial blood pressure and parameters obtained by a Swan-Ganz catheter. In healthy anaesthetized patients (n = 23), the effects of a dose of 0.1 mg X kg-1 pancuronium (group A) were compared to those of two doses of vecuronium: 0.1 mg X kg-1 (group B) and 0.3 mg X kg-1 (group C). Pancuronium induced an increase in heart rate (+12%), arterial pressure (+16%) and cardiac index (+8%). No change occurred with vecuronium. In patients under mechanical ventilation in an intensive care unit, we compared the effects of pancuronium 0.1 mg X kg-1 (group D; n = 10), d-tubocurarine (group E; n = 11), vecuronium 0.1 mg X kg-1 (group F; n = 9) and 0.3 mg X kg-1 (group G; n = 10). Pancuronium induced an increase in heart rate (+12%), arterial pressure (+8%) and cardiac index (+9%). d-Tubocurarine induced an increase in heart rate (+6%), a decrease in arterial pressure (-24%) and cardiac index (-17%). No change was observed after vecuronium 0.1 mg X kg-1. After vecuronium 0.3 mg X kg-1, the changes were minimal: a slight decrease in arterial pressure (-5%), a very slight (+3%) and transient (3 min) increase in heart rate were observed. The doses were approximately equipotent in groups A, B and C, whereas the dose of 0.3 mg X kg-1 in group G is about 10 times the 90% effective dose of vecuronium. In geriatric patients with per- or postoperative circulatory deficiency (group H; n = 10, mean age 83 yr), no hemodynamic side effects were observed. Vecuronium seems to be a non-depolarizing neuromuscular blocking agent devoid of cardiovascular side-effects at the generally usual doses.

Adult↗
PubMed1983

[Clinical use of vecuronium during celioscopy].

In order to determine if vecuronium can be used for short operations, 40 women were studied during laparoscopy, randomly assigned to four groups: suxamethonium 1 mg X kg-1 in a single bolus followed by an infusion (group A), vecuronium 0.05 mg X kg-1 (group B), vecuronium 0.06 mg X kg-1 (group C) and vecuronium 0.07 mg X kg-1 (group D). Mean duration of operation was 22-25 min. Tracheal intubation can be performed in good conditions in all patients in group A and D, in 5/10 in group B and in 7/10 in group C. During laparoscopy, muscular relaxation was considered excellent in all patients in group A and D, 5/10 sufficient and 5/10 excellent in group C, 5/10 insufficient and 5/10 sufficient in group B. There were 7 reinjections in group B, 2 in group C and 1 in group A. The delay between the end of the procedure and extubation was the same in group A and C (7 min). This delay was significantly higher in group D (9 min). The delay between extubation and positive head lift test was significantly higher in group D. We conclude that the time course of action of vecuronium 0.06 mg X kg-1 is that required for a pelvic laparoscopy of 22-25 min; however, the conditions of intubation are not always perfect. Intubation is easier with a 0.07 mg X kg-1 dose; this dose induces a slight delay for extubation and positive head lift test. In all cases, the patient must be closely watched in a recovery ward.

Adult↗
PubMed1982

[Early jejunal catheter feeding in heavy gastrointestinal surgery (author's transl)].

Fifty patients undergoing extensive gastrointestinal surgery were fed through a jejunal catheter introduced during the operation. After surgery, feeding was started 48 hours, except for 10 patients who had pre-operative intestinal obstruction or a suture below the site of liquid food instillation. The decision to feed patients enterally must by taken during surgery, and the method requires a trained nursing team, but it considerably improves the patient's nitrogen balance and, accessorily, his comfort. There does not seem to be any contra-indication. The onset of enteral feeding only depends upon the type of operation performed.

Catheterization↗
PubMed1982

[Prevention of per-operative myocardial ischemia with continuous nitroglycerin infusion].

The aim of this work is to assess the possible beneficial effects of intra and post operative nitroglycerin infusion in patients with disabling angina pectoris (Class III of the New-York Heart Association). We thus compared the occurrence of myocardial ischemia detected by means of continuous electrocardiographic recording of lead V5 in 31 patients which were divided in two groups. The control group (I) included 16 patients, group II included 15 patients undergoing similar surgical procedures, given a permanent nitroglycerin infusion. Mean dose of nitroglycerin was 0,91 +/- 0,18 micrograms . kg-1 . min-1. An ischemic type S T segment depression occurred in 15 out 16 patients in group I and in only 3 out of 15 patients in group II (p less than 0,001). No S T segment depression occurred following a decrease of more than 25 p. 100 in systolic blood pressure in 8 patients of group II at the time of induction. These hypotensive episodes were easily corrected by decrease of the nitroglycerin infusion rate associated with a rapid blood volume expansion. The very high incidence of intra operative myocardial ischemia in control group demonstrates the severity of the coronary disease in the observed patients. The significantly lower frequency of ischemic S T segment depression observed in the patients given nitroglycerin infusion suggests that this drug is highly effective in preventive myocardial ischemia in patients with severe coronary artery disease. The administration of nitroglycerin in our patients had been easy to control, blood pressure reaching normal value within a few minutes after decrease of the rate of drug infusion when needed.

Aged↗
PubMed1982

[Nitrous oxide and pressures exerted on the trachea by endotracheal tubes. Study on a tracheal model].

The authors studied the effects of nitrous oxide diffusion, using a tracheal model, on the pressure of several endotracheal tube cuffs. Studies carried out showed an increase in volume and pressure of the cuffs related to time exposure and nitrous oxide concentrations used. Use of a self-controlled pressure cuff or filling the cuff with inspired gas composition should be of value to counteract or to prevent the diffusion effect.

Anesthesia, Inhalation↗
PubMed1982

Suppression of antidiuretic hormone hypersecretion during surgery by extradural anaesthesia.

The concentrations of antidiuretic hormone in plasma and urine were determined in three groups of patients submitted to the same operative procedure. Seven (group I) underwent general anaesthesia with thiopentone, fentanyl and nitrous oxide and received an infusion of isotonic saline solution 5ml min-l. Seven patients (group II) anaesthetized similarly, received isotonic saline solution 15 ml min-1. In group III (five patients) anaesthesia was produced by extradural blockade. Surgery under general anaesthesia induced a significant increase in plasma and urine ADH concentrations which were not modified by the fluid load. Extradural anaesthesia suppressed almost completely the release of ADH during surgery. This effect of extradural anaesthesia could be related to the interruption of conduction along nociceptive neural pathways.

Aged↗
PubMed1982

Plasma pharmacokinetics of morphine after i.m., extradural and intrathecal administration.

Eighteen patients received morphine 0.2 mg kg-1 in 0.9% saline i.m. (n = 6), extradurally (n = 6), or in a 10% dextrose solution intrathecally (n = 6) for pain relief operation. Plasma unmetabolized morphine was isolated by extraction using liquid-solid chromatography and measured by radioimmunoassay. Conjugated morphine was calculated from the difference between total immunoreactive morphine and unmetabolized morphine. Initial vascular absorption was significantly less in the intrathecal group than in the i.m. and extradural groups. This accounts for persistence of plasma unmetabolized morphine at 24 h and for more prolonged analgesia in the intrathecal group. Prolonged analgesia observed following extradural and intrathecal administration was caused by a small quantity of unmetabolized morphine. Extradural and i.m. groups showed the same pharmacokinetic patterns although extradural analgesia is much more prolonged. Morphine glucuronide appeared later in blood in the intrathecal group than in the two other groups.

Epidural Space↗
PubMed1982

Resistance to sodium nitroprusside in hypertensive patients.

Eleven patients in hypertensive crisis were treated with iv sodium nitroprusside (SNP). In all cases, rapid clinical improvement was obtained. Nevertheless, 9 patients developed progressive resistance to the hypotensive effect of the drug. For the first 2 h, the mean infusion rate was 1.68 +/- 0.64 micrograms/kg . min. For the next 6 h, the mean infusion rate had to be increased to 3.1 +/- 1.14 micrograms/kg . min in order to maintain diastolic blood pressure below 110 mm Hg. Hemodynamic measurements demonstrated that this resistance was related to a marked rise in cardiac index without tachycardia. In the 6 patients with pulmonary edema who developed resistance to SNP, blood pressure control was obtained by fluid depletion. In the 3 patients without pulmonary edema who developed resistance to SNP, blood pressure control was obtained by iv acebutolol. The authors conclude that SNP rapidly improves critical hypertension. Progressive resistance to the hypotensive effect of the drug can occur in some cases and is related to a marked rise in cardiac index, which can be rapidly antagonized with fluid depletion or a beta-blocking agent to avoid SNP accumulation and cyanide toxicity.

Acebutolol↗
PubMed1982

Clinical predictors of intraoperative myocardial ischemia in patients with coronary artery disease undergoing non-cardiac surgery.

In order to detect the incidence of myocardial ischemia during the perioperative period and to determine during which situation it occurred, continuous monitoring of the electrocardiogram by the Holter method was used in 51 patients with coronary artery disease who were undergoing a vascular surgical procedure. Clinical parameters measured preoperatively were evaluated as predictors of the occurrence of myocardial ischemia during the perioperative period. Twenty of 51 patients demonstrated 36 episodes of myocardial ischemia, which started in 11 cases during induction. Fourteen of 16 patients with disabling angina pectoris (Class III and IV) developed myocardial ischemia, whereas only six patients out of 35 with Class II or less or no angina experienced peroperative ischemic episodes (P less than 0.001). All the patients without or with only mild angina who experienced perioperative ischemia showed ST-T abnormalities at the preoperative resting electrocardiogram. Our data suggest that the risk of intraoperative myocardial ischemia can be predicted during the preoperative period by the degree of disability exhibited by patients with coronary artery disease.

Adult↗