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Biomedical subjects

J M Bernard

Publications and source records attributed to J M Bernard.

At least 37 records · Page 2Linked to original sources
PubMed1995

Comparison of intravenous and epidural clonidine for postoperative patient-controlled analgesia.

Both epidural and intravenous clonidine are used to provide postoperative analgesia, but in predetermined doses. This double-blind randomized study was designed to 1) determine the clonidine dose inducing pain relief after major orthopedic surgery, when controlled by patient, either intravenously or epidurally; and 2) assess whether these two administration routes are clinically equivalent. At the first complaint of pain after scoliosis correction, patients received an initial dose of 8 micrograms/kg clonidine during 30 min either intravenously (n = 12) or epidurally (n = 12). Then, clonidine was given using a patient-controlled analgesia pump via the corresponding administration route. In both cases, the bolus dose was set at 30 micrograms and the lockout interval at 15 min. Pain (0-100 scale), clonidine requirements, sedation (0-4 scale), and hemodynamics (by fiberoptic pulmonary artery catheter) were measured before and 15, 30, 120, 240, 360, 480, and 600 min after the loading dose was started. Plasma clonidine concentrations and arterial blood gases were determined at the 15th, 30th, 240th, and 480th min. Self-administered and total clonidine doses were larger in the intravenous group than in the epidural group (at 600 min: 372 +/- 110 vs 235 +/- 144 micrograms, and including the initial dose, 814 +/- 114 vs 652 +/- 187 micrograms; mean +/- SD). Clonidine administration resulted in pain relief and sedation in both groups but, for comparable pain relief, sedation scores were lower in the epidural group. No intergroup differences in hemodynamic data were observed, although the decrease in blood pressure occurred earlier in the intravenous group. Plasma clonidine concentrations were higher in the intravenous group than in the epidural group (2.5 +/- 0.6 vs 1.5 +/- 0.5 ng/mL after the initial dose and 2.1 +/- 0.5 vs 1.5 +/- 0.4 ng/mL during self-administration; mean +/- SD). We conclude that analgesia can be achieved postoperatively by both epidural and intravenous clonidine administration. The epidural route is associated with significant reductions in self-administered clonidine dose, and thus in the plasma clonidine concentration, and the level of sedation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Induction of anaesthesia by propofol and hepatic blood flow in the rabbit.

Effects of propofol (12.5 mg kg-1, i.v. bolus injection) or 0.9% sodium chloride on arterial blood pressure, arterial blood gases and hepatic circulation (radio-labelled microsphere technique) were studied in 15 conscious and unpremedicated rabbits. No significant changes were observed after sodium chloride. Propofol resulted in anaesthesia, respiratory depression (-49 +/- 14% decrease in PaO2; mean +/- SD) and hypotension (-49 +/- 13% decrease in mean arterial pressure; mean +/- SD) but no changes in hepatic arterial and portal venous blood flows. We conclude that propofol does not affect the liver circulation despite marked depression of mean arterial pressure and respiration.

Anesthesia↗
PubMed1995

[Influence of post-infarction myocardial revascularization on the prevalence of delayed potentials].

It has been shown that the presence of ventricular late potentials is a predictive factor of ventricular tachycardia and sudden death after myocardial infarction. The value of thrombolysis in the reduction of the prevalence of ventricular late potentials is now well established. However, the effects of other modes of revascularisation is less well known and more controversial. The authors undertook a retrospective study of 139 consecutive patients undergoing coronary angiography after primary myocardial infarction. The presence of ventricular late potentials fulfilling two of the three usual criteria was sought after a revascularisation procedure. The overall prevalence of ventricular late potentials was 30.9%. This was not affected either by the site of infarction of by the single or multiple character of the coronary artery disease. In addition, the left ventricular ejection fraction was not significantly different in patients with positive ventricular late potentials compared with the others. On the other hand, revascularisation of the culprit lesion responsible for the infarction was strongly correlated with a lower incidence of ventricular late potentials (p < 10 (-5)). In particular, the different incidence of positive late potentials between the dilated (9.3%) and non-dilated group (49.2%) was statistically significant (p < 10 (-6)) without any correlation to the single or multiple character of the coronary disease. The authors discuss the different reports in the literature concerning the effects of angioplasty and coronary bypass surgery on the incidence of ventricular late potentials. Conclusion; the review of the literature shows that thrombolysis significantly reduces the incidence of late potentials after myocardial infarction and the present study suggests that angioplasty and coronary bypass surgery may also be effective.

Arrhythmias, Cardiac↗
PubMed1995

[Analgesia after surgery of the spine in adults and adolescents].

Postoperative pain after spinal surgeries is highly dependent on the number of vertebrae included in the operation and on its invasiveness, opposing two extremes, discectomies and cyphoscoliosis corrections. Opiates by intravenous route remain the reference, either continuously given in predetermined doses, or better using a patient-controlled device. Nonsteroidal and steroidal anti-inflammatory drugs are widely popular for medical approach of sciatalgia and it is quite logical to use them for reducing, even to suppress, opiates after spinal surgeries. Supported by many studies, spinal administration of analgesics (opiates, alpha 2-agonists, corticosteroids) may be of interest in pain treatment of spinal surgeries. In order to prolong locoregional analgesia, a catheter may be inserted into epidural space by caudal route or surgically, before skin closure. Morphine is the most popular agent in this indication. Also, epidural clonidine results in excellent pain relief, but is associated with hypotension and marked sedation. In discectomy, injection of dexamethasone into the operative field has been proposed. Whatever the technique used, early diagnosis of neurological complications of spinal surgery should be not ruled out by postoperative analgesia.

Adolescent↗
PubMed1994

Ketoprofen for pain after hip and knee arthroplasty.

In a double-blind, randomized study, we have compared the effects of i.v. ketoprofen 200 mg followed by 12.5 mg h-1 over 13 h, with those of extradural morphine 4 mg in 32 patients after hip and knee arthroplasty. A visual analogue scale was used to score pain before analgesic administration (first complaint after operation), 1 h after and every 2 h subsequently. Pain reduction 1 h after the start of analgesia was mean 44% (SEM 17%) in the extradural morphine group and 54% (9%) in the ketoprofen group (ns). There were no significant differences between groups in pain scores, pain reduction and additional analgesia requirement (i.v. paracetamol). Naloxone 5 micrograms kg-1 h-1 was required for hypercapnia exceeding 6.0 kPa in three patients in the extradural morphine group (vs none in the ketoprofen group; ns). There were no differences between groups in side effects, except for urinary retention, which was more frequent in the extradural morphine group (P < 0.05). As there were few differences between i.v. ketoprofen and extradural morphine, we conclude that ketoprofen may be an efficient alternative to extradural morphine after hip and knee arthroplasty.

Adult↗
PubMed1994

Balanced postoperative analgesia: effect of intravenous clonidine on blood gases and pharmacokinetics of intravenous fentanyl.

Agonist interactions in antinociceptive effects between clonidine and opioids can be used to reduce opioid requirements in surgical patients. However, clonidine can cause marked sedation and associated respiratory dysfunction. Thus, the benefit of using clonidine to reduce opioid use on respiration is questionable. This double-blind randomized study compared the analgesic efficacy, arterial blood gases, and pharmacokinetics of an intravenous (IV) infusion of fentanyl 75 micrograms/h and a mixture of fentanyl 25 micrograms/h plus clonidine 0.3 micrograms.kg-1.h-1 in 32 healthy young adults after surgery for scoliosis correction. Oxygen saturation (FIO2: 0.21) and respiratory rate were monitored as well as supplemental analgesia demands (IV ketoprofen via a patient-controlled device), pain, sedation, and hemodynamics. Oxygen and naloxone (5 micrograms.kg-1.min-1) were administered, respectively, if more than three episodes of oxygen saturation less than 90% were observed within 10 min and if PaCO2 was higher than 50 mm Hg. Pain relief, sedation, and ketoprofen requirements were similar in both groups. The number of episodes of arterial desaturation less than 90% (> 20 s) was 106 for four patients in the fentanyl group (versus none in the clonidine-fentanyl group). Naloxone was required in six patients and oxygen in two patients of the fentanyl group (versus none in the group receiving clonidine). Dopamine, 10 micrograms.kg-1.min-1, was required in one patient of the clonidine-fentanyl group to correct hypotension. Mean arterial blood pressure, plasma clearance, and the elimination rate constant of fentanyl were lower in the clonidine-fentanyl group than in the fentanyl group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Which way for the administration of alpha 2-adrenergic agents to obtain the best analgesia?].

Mechanisms of the analgesic actions of alpha 2-adrenergic agonists are likely related to various modulating systems of nociceptive neurotransmission, especially those dependent on opiate receptors. Analgesic action of alpha 2-adrenergic agonists implies alpha 2-adrenergic receptors, strategically located on the dorsal horn neurones of the spinal cord to inhibit the release of substance P in response to peripheral stimuli. However, these receptors are included in the control that supraspinal sites exert via the descending medullospinal noradrenergic pathway. Because of its high lipophilic structure, alpha 2-adrenergic agonist can easily penetrate into the central nervous system, reproducing the effects of activation of medullospinal noradrenergic pathway. Alpha 2-adrenergic agonists have been found to be efficient in human pain treatment after systemic, spinal or troncular administration, but there were few randomized clinical studies comparing analgesia potency and adverse effects of either systemic or regional administrations. Clonidine added to local anaesthetic agents increases the analgesic effects in a greater extent than systemic administration of similar dose, probably because this effect depends on the local clonidine concentration. Extradural administration of clonidine is also more efficient than systemic administration, at least when high doses are injected. This superiority is questionable when low-dose clonidine is used. Adverse effects are quite similar in both systemic and spinal routes. Invasiveness of extradural route may be considered in regard to the gain which may be expected in analgesia efficiency.

Adrenergic alpha-Agonists↗
PubMed1994

[Data exploration using post-factorial analysis: use of structured data interrogation software].

The language for interrogating data (LID) allows the graphical and numerical exploration of a cloud of points resulting from a factorial analysis. The interest of a post-factorial analysis in epidemiology is shown in the present paper: a measure of the department effect; a measure of year effect; an assessment of the adjustment on one factor in the framework of a survey on the risk factors of milk quality.

Animals↗
PubMed1993

Diltiazem reduces the dose requirement for nitroprusside-induced hypotension.

The efficacy of diltiazem, a calcium channel blocker, for reducing the dose requirement for nitroprusside-induced hypotension was studied in 20 healthy patients during spine fusion for scoliosis. Anesthesia included methohexital (3 mg/kg followed by 3 mg.kg-1.h-1 intravenously), nitrous oxide, and alfentanil (40 micrograms/kg, followed by 0.7 microgram.kg-1.min-1 intravenously). Patients were assigned randomly to two groups, receiving either nitroprusside alone or nitroprusside and diltiazem (bolus of 80 micrograms/kg with two consecutive infusions of 4.5 micrograms.kg-1.min-1 during the first 30 min and then 1.3 micrograms.kg-1.min-1). Nitroprusside was used to maintain mean arterial pressure at 55-60 mm Hg in both groups. Hypotension was obtained in similar times, 4 min in the group receiving nitroprusside alone (range, 1-8 min) and 2 min in the group receiving nitroprusside and diltiazem (range, 1-8 min). Nitroprusside administration lasted 186 +/- 17 min (mean +/- SEM) in the group receiving nitroprusside alone and 214 +/- 26 min (mean +/- SEM) in the other group (NS). After hypotension, arterial blood pressure returned to its initial value in a time of 7 min in the group receiving nitroprusside alone (range, 5-9 min) and 9 min in the group receiving nitroprusside and diltiazem (range, 7-13 min) (NS). Cumulative doses of nitroprusside were larger in the group receiving nitroprusside alone (0.47 +/- 0.07 mg/kg; mean +/- SEM) than in the other group (0.24 +/- 0.05 mg/kg; mean +/- SEM) (P < 0.01). Significant increase in plasma thiocyanate concentration, cardiac index, and heart rate was observed only in the group receiving nitroprusside alone, but no intergroup differences were found.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[How to reduce the consumption of opioids used in the postoperative period].

The use of local anesthetic agents, non steroidal anti-inflammatory drugs and clonidine, and the use of patient-controlled devices are among the most efficient techniques to reduce postoperative requirements in narcotics. It is likely that this practice is accompanied by a reduced risk of respiratory depression and may result sometimes in substantial improvement of the pain relief.

Adrenergic alpha-Agonists↗
PubMed1993

Heel pain in the older patient.

Older Americans are the fastest growing segment of the US population. For this group, mobility is a significant factor in individual well-being. Heel pain is primarily a symptom found in adults, and like most health problems, increased age has a compounding effect on most disease processes. If heel pain becomes the cause of immobility in an older patient, significant consequences may arise. The true prevalence of heel pain in older individuals is not known precisely. The frequency may lie between 12.5% and 15% on the basis of reports in the literature. The scientific basis of these figures, however, is open to question. No one method of organizing heel pain according to a causative agent or condition is accepted universally. A review of the literature, however, reveals that most reporters ultimately include the same elements in whatever schema they use. In general terms, management of heel pain, regardless of the cause, can be organized according to noninvasive to invasive treatment methods. The authors have found the categories of mechanical, pharmacologic, and surgical to be useful. Selection of a therapeutic method is based on the patient's specific physical circumstance and social situation.

Aged↗
PubMed1992

Effects of sevoflurane and isoflurane on hepatic circulation in the chronically instrumented dog.

To compare the effects of sevoflurane and isoflurane on hepatic circulation, eighteen dogs were chronically instrumented for measurements of mean aortic blood pressure and cardiac output and for simultaneous measurements of hepatic and portal blood flows. Each animal was studied while awake and during 1.2 and 2 MAC of either isoflurane or sevoflurane. Both anesthetics induced tachycardia and a dose-dependent decrease in mean aortic blood pressure (isoflurane -27% and -39%; sevoflurane -22% and -37%). Cardiac output decreased only at the highest concentration (isoflurane -10%; sevoflurane -21%). During sevoflurane, portal blood flow decreased at both 1.2 and 2 MAC (-14 and -33%, respectively), whereas an increase in hepatic arterial blood flow was recorded at 2 MAC (+33%). During isoflurane, the only significant change was a decrease in portal blood flow (-16%) at 1.2 MAC. Neither anesthetic significantly changed renal blood flow. Therefore, both anesthetics led to similar systemic and hepatic vasodilation.

Anesthetics↗
PubMed1992

Long-term hypotensive technique with nicardipine and nitroprusside during isoflurane anesthesia for spinal surgery.

Short-term infusion of nicardipine can be used to induce deliberate hypotension but may result in plasma drug accumulation. To assess long-term nicardipine administration for deliberate hypotension in 10 patients in a moderately hemodiluted state who were undergoing spinal surgery, hemodynamics and plasma nicardipine concentrations were concomitantly measured before and 20, 80, and 140 min after starting nicardipine, at drug discontinuation, and 20 and 80 min later. A dose of 6.2 +/- 0.9 mg (mean +/- SEM) of nicardipine was initially required to obtain mean arterial blood pressures at 55-60 mm Hg. Maintenance doses of nicardipine were 3-5 mg/h. The duration of nicardipine administration was 270 +/- 20 min (mean +/- SEM). Hypotension was associated with decreased systemic and pulmonary vascular resistances, increased cardiac index, and decreased arteriovenous difference in O2 contents. Only two patients required homologous blood transfusion. Plasma nicardipine concentrations peaked at 110 +/- 21 ng/mL (mean +/- SEM) and then decreased to 38 +/- 11 ng/mL (mean +/- SEM) without changes in arterial blood pressure. After vasodilator discontinuation, hypotension was observed during a mean time of 43 min (range 27-88 min) despite plasma concentrations less than 20 ng/mL. No relationship was found between plasma nicardipine concentrations and hemodynamics. These findings suggest that an increasing effect of nicardipine over time may occur during prolonged administration. Because the reasons for this hysteresis remain unclear, use of nicardipine infusion during major surgery and anesthesia requires particular caution.

Adult↗
PubMed1992

Warfarin sodium. Practitioner beware.

The use of warfarin sodium in the US has increased dramatically over the last 40 years. Warfarin sodium or Coumadin is the most popular oral anticoagulant used in the US. The podiatric physician frequently encounters patients taking this agent and therefore needs to understand its potential impact. This article will familiarize the reader with the history, pharmacology, clinical applications, side effects, and frequent drug interactions encountered with warfarin sodium.

Contraindications↗
PubMed1991

[Effects of intravenous clonidine on postoperative shivering].

A study was designed to assess the possible effects of intravenous clonidine on postoperative shivering. Fifty patients undergoing spinal fusion under isoflurane anaesthesia were randomly assigned to two groups (n = 25). Patients in one group were given intravenous clonidine (5 micrograms.kg-1 during the first hour, and 0.3 microgram.kg-1.h-1 thereafter) or placebo. Shivering intensity (rated from 0 to 2) and pulmonary artery blood temperature (theta) was recorded every ten minutes for two hours. Haemodynamic and metabolic data were obtained by way of a Swan-Ganz catheter prior to administering the test drug, and then after 1 and 2 hours. On arrival at the recovery room, theta was 36.2 +/- 0.3 degrees C in the clonidine group, and 36.5 +/- 0.2 degrees C in the placebo group. There were no significant differences in shivering between the two groups. Clonidine significantly decreased blood pressure, heart rate, cardiac output and whole body oxygen consumption. The patients in these series were free from any cardiac disease. Further studies are required to assess the possible beneficial effects of clonidine on postoperative oxygen consumption in patients suffering from heart failure.

Adult↗