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Biomedical subjects

P Viars

Publications and source records attributed to P Viars.

At least 217 records · Page 12Linked to original sources
PubMed1982

[Myocardial ischemia and carotid surgery. Holter study of 21 severe coronary patients. Preventive effect of intravenous trinitrin].

Cervical carotid artery surgery is increasingly being performed in elderly, polyvascular, high risk patients, some of whom have severe coronary artery disease. Is this right? The effects of this almost routine surgical procedure from the technical point of view were analysed with respect to the coronary lesions. 1. A retrospective study of coronary events occurring in the peroperative or immediate postoperative period and at short term was carried out in 367 patients aged over 70 years old (average 73,4 years) undergoing 424 cervical carotid artery procedures with a particularly high coronary risk. 2. A prospective study of ischemic ECG changes occurring in the period between induction of anaesthesia and the 4th postoperative day was performed by Holter monitoring in 21 patients with severe coronary artery disease. The mortality and morbidity observed were very low and could be further reduced by certain anaesthetic and pre-and postoperative techniques. In particular, prophylactic intravenous trinitrin (0,5 to 1,5 gamma kg/min) was most effective in protecting the myocardium in 15 patients with severe angina (classes III and IV of the NYHA classification). The authors conclude that the surgical result depends mainly on the neurological status of the patients, the best results being obtained in asymptomatic patients (stage 0) or those having suffered transient ischemic attacks (stage 1). The global mortality and morbidity rate was less than 2 p. 100 in those groups. On the other hand, long-term survival depends mainly on the severity of the coronary artery disease.

Aged↗
PubMed1981

Plasma morphine concentration after intrathecal administration of low doses of morphine.

Plasma morphine concentration was measured in eight patients who received morphine 0.02 mg kg-1 intrathecally. The concentration was less than 0.5 ng ml-1 at 2 min and 10 min, 2 +/- 1 ng ml-1 at 30 min, 3 +/- 2 ng ml-1 at 1 h, 6 +/- 4 ng ml-1 at 3 h, 5 +/- 3 ng ml-1 at 12 h, 0.8 +/- 0.2 ng ml-1 at 24 h and less than 0.5 ng ml-1 at 36 h. The small plasma morphine concentrations we observed after intrathecal administration of morphine indicated that analgesia is a result of an action of morphine on opiate receptors, either spinal or cerebral.

Humans↗
PubMed1981

Risk of advanced heart block during extradural anaesthesia in patients with right bundle branch block and left anterior hemiblock.

Electrocardiographic recording by Holter monitoring demonstrated the absence of any modification, however minimal, of the intranodal conduction during surgical procedures under extradural anaesthesia in 20 patients with right bundle branch block (RBBB) and left anterior hemiblock (LAHB) but without symptoms. These data suggest that extradural anaesthesia can be used safely in patients with asymptomatic chronic RBBB and LAHB without prophylactic insertion of pacemakers. However, patients having experienced either syncope or transient Mobitz II second degree AV block are likely to have a trifascicular block and increased risk of advanced heart block during extradural anaesthesia.

Aged↗
PubMed1981

Postoperative spinal analgesia with morphine.

Patients with pain after operation received morphine hydrochloride intrathecally in doses of 0.02 mg kg-1 (n = 30) and 0.2 mg kg-1 (n = 30). The high-dose group showed slightly longer-lasting and more potent analgesia than the low-dose group. Sedation, decreases in heart rate and systolic arterial pressure, oliguria, nausea and urinary retention were more frequent in the high-dose group. Two patients of the high-dose group showed evidence of respiratory depression which appeared after a late change in posture (7 and 11 h). We conclude that postoperative analgesia with intrathecal morphine 0.02 mg kg-1 must be followed by a prolonged head-up posture and be performed in hospital units where the treatment of respiratory depression is competent.

Clinical Trials as Topic↗
PubMed1981

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

Seventeen patients received morphine 0.2 mgkg-1 in a 10% dextrose solution i.m. (n = 5), extradurally (n = 6) and intrathecally (n = 6) for pain after operation. Morphine was measured in plasma by radioimmunoassay. Plasma immunoreactive morphine concentration was significantly less after intrathecal administration after i.m. and extradural administration (P less than 0.05) at 2, 10, 15 and 30 min. We conclude that morphine given extradurally has a greater initial rate of vascular absorption than morphine given intrathecally and is similar to that observed after i.m. administration.

Absorption↗
PubMed1981

Hemodynamic and metabolic effects of morphine in the critically ill.

To assess the effects of i.v. injection of morphine, 0.5 mg/kg, hemodynamic studies were performed on 24 critically ill patients under controlled ventilation. An esophageal balloon was used to estimate intrapleural pressure and transmural cardiac filling pressures were calculated. After injection of morphine, there were significant decreases in heart rate (13%), cardiac index (18%), stroke index (17%) and arterial pressure (15%) and there was a nonsignificant increase in esophageal pressure (15%). Transmural cardiac filling pressures decreased significantly (21% for the pulmonary wedge pressure); intravascular filling pressures were unchanged. Oxygen consumption decreased significantly, by 21%, in 10 patients with initially elevated oxygen consumption and by 9% in 14 patients with initially normal oxygen consumption. The oxygen extraction ratio was unchanged, suggesting that the decrease in oxygen consumption was caused by decreased oxygen demand rather than by inadequate oxygen delivery. These results indicate that the hemodynamic effects of morphine (0.5 mg/kg) administered to critically ill patients were associated with a significant decrease in oxygen consumption, which probably reflected sedation and analgesia.

Adult↗
PubMed1981

[Sulfentanil citrate. Administration of intramuscular injections in conscious man (author's transl)].

In the case of a conscious man suffering from a painful injury in the facial and trigeminal nerves, the administration of intra-muscular injections of increasing doses of morphine and sulfentanil provokes constant analgesia in direct proportion to the administered dose. The admitted dosages for each product are as follows. M = 0,100, 0,150, 0,200 mg/kg S = 0,00015, 0,0003, 0,0006 mg/kg. Sulfentanil is a highly active analgesic whose activity is about 333 times greater than that of morphine and 13 times greater than that of fentanyl. In the case of each of the 3 products, the point at which analgesia becomes clinically discernable is the same. Optimum intensity of action of the analgesia is arrived at in all 3 cases within a period of 60 to 90 minutes. The higher the dose administered, the longer sulfentanil can be expected to work. Although effective for a shorter period of time than morphine and fentanyl sulfentanil effectiveness is too great for it to be considered a short-acting analgesic.

Adult↗
PubMed1981

[Sulfentanil and morphine by intramuscular injection. Side effects compared in conscious man (author's transl)].

For the purposes of this study, sulfentanil is administered to conscious men in increasing doses (0,00015, 0,0003, 0,0006 mg/kg) by intra-muscular injection, and the results are compared with those obtained in the same condition by administration of morphine (0,100, 0,150, 0,200 mg/kg). The administration of both drugs provokes the same side-effects. The failure of the breathing rate is as fast as observed following the administration of morphine in equi-analgesic doses. As in the case of analgesia, the time taken for the falling off of the breathing rate to occur, and its duration are shorter with sulfentanil, than with morphine. In any case their persistence is too great for one, to be able to consider sulfentanil as a drug of very short-term effect. The effects of sulfentanil on the cardiac rhythm (bradycardia) and on arterial pressure (low blood pressure) are slightly less intense, but above all, much shorter than that of a equi-analgesic dose of morphine. The other side-effects which are clinically discernable, particularly those felt by the patient, vomiting and changes in behaviour patterns are minimal; certainly lesser after administration of S than after tha of M. The sedative value are the same and often identical after administration of both drugs. Finally, the euphoric effect of sulfentanil appears to be slighter than that of morphine.

Adult↗
PubMed1981

[Blockade of renin secretion by epidural anaesthesia (author's transl)].

In order to determine the rule of neurologic stimuli on the renin-angiotensin system, during surgery, plasma renin activity (PRA) was measured in two groups of patients submitted to either general (group I, N = 7) or epidural (group II, N = 5) anaesthesia during total hip replacement. Salt intakes were normal for all patients before the operation and the perfusion rate, of isotonic saline solution was 5 ml/minute during the surgical procedure. A significant rise in PRA was observed after the skin incision in the first group of patients under general anaesthesia. Epidural anaesthesia suppressed the renin response to surgery. The blockade of conduction along nervous pathways afferent from the surgical area and along renal sympathetic pathways explains the effect of epidural anaesthesia. The lack of increase in PRA despite a significant fall in blood pressure after epidural anaesthesia, also suggests an inhibition of the catecholamines secretion.

Anesthesia, Epidural↗
PubMed1981

[Suxamethonium. Haemodynamic study in man excepting general anaesthesia (author's transl)].

Haemodynamic effects of suxamethonium IV 1 mg/kg were studied in eight comatose, mechanicaly ventilated, normotensive patients. Drug interference, including atropine was avoid. A transitory but significant increase in heart rate and cardiac output (CO) was observed, respectively + 27 p. cent (p less than 0.02) and + 29 p. cent (p less than 0.025) at the first minute. Right auricular, pulmonary capillary wedge, and pulmonary arterial pressures increased significantly from the first to the eighth minute. Mean arterial blood pressure unsignificantly increased (+ 5 p. cent) wether systemic arterial resistance decreased from - 11 p. cent (p less than 0.02) at the first minute. No arrhythmia occurred throughout the study. In the conditions of this study suxamethonium induces an early and transient increase in CO. Both tachycardia and increased venous return can explain the rise in CO. Such an increase could be due to the transient abdominal hyperpressure, and can be one of the factors which explain the poor tolerance of suxamethonium in patients with heart failure.

Adolescent↗
PubMed1981

[Intervention among patients with right bundle branch block and left anterior hemiblock. Operatory risk (author's transl)].

In order to assess the risk of advanced heart block during anesthesia in patients with right bundle branch block and left anterior hemiblock, 35 consecutive patients were monitored throughout the pre-, intra- and postoperative period. As conventional ECG monitoring may only detect advanced atrioventricular block, patients were monitored according to the Holter method which can easily detect even minor changes of atrioventricular conduction namely slight increased PR interval or dropped P wave. All patients were asymptomatic, in normal sinus rhythm without second degree AV block. Surgical procedures were performed under general anesthesia (n = 15) and epidural anesthesia using lidocaine (n = 20). No episode of second or third degree atrioventricular block occurred. The only modifications observed were rare and transient increase of PR, occurring during surgical procedures in 5 patients, always associated with a sinus bradycardia. They immediately regressed at the termination of the sinus bradycardia either spontaneously or following atropine injection, strongly suggesting the responsability of increased vagal tone. Thus general or epidural anesthesia did not compromise infranodal conduction in any of the observed patients. These data indicate that anesthesia can be safely used without prophylactic preoperative insertion of pacemakers in patients with asymptomatic chronic right bundle branch block and left anterior hemi-block.

Aged↗