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Biomedical subjects

F Bonnet

Publications and source records attributed to F Bonnet.

At least 235 records · Page 13Linked to original sources
PubMed1990

[Comparison between conventional and continuous spinal anesthesia using bupivacaine].

A study was carried out to find out whether dividing the dose of local anaesthetic would give a better control of the spread and duration of sensory blockade due to spinal anaesthesia. It was carried out in 34 patients (mean age 62 years) scheduled for elective limb vascular surgery. All were classed ASA 2 or 3. Sensory blockade was assessed using a fine needle, and the degree of motor blockade with Bromage's scale. This was carried out every 5 min for the first 30 min, and thereafter, every 15 min until recovery from anaesthesia was complete. In the first group of patients (n = 16), spinal anaesthesia was obtained with a 26 gauge needle, the patient lying on his side; 4 ml of 0.5% bupivacaine were injected (1 ml every 10 seconds) before putting the patient supine. In the second group (n = 18), the catheter for continuous spinal anaesthesia was set up with the patient in the same position as for the first group. Once a length of 1 cm had been introduced in the subarachnoid space, the patient was placed supine and 2 ml of 0.5% bupivacaine were injected. If 15 min later sensory blockade did not reach T10, further 0.5 ml aliquots were given every 10 min so as to obtain a level of sensory blockade between T9 and T11. Maximum extension of sensory blockade was 15.1 +/- 2.3 metamers in group 1, with an extension to T3 in 2 patients. In group 2, 12.9 +/- 3.1 mg bupivacaine anaesthetized 14.2 +/- 1.9 metamers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Diagnosis of severe pulmonary embolism by transesophageal echocardiography].

A 56-year-old woman was admitted to the Emergency Department for profuse diarrhoea, associated with hypokaliemia and dehydration. A subclavian venous catheter was inserted after she had a cardiac arrest. Six days later, the subclavian and innominate veins were thrombosed. Prophylactic low molecular weight heparin was then replaced by sodium heparinate. The patient's platelet count decreased to 65 G.1-1. It was nevertheless decided to remove her villous tumour. After the operation, the patient became shocked, with worsening thrombocytopaenia (15 G.1-1). She was unresponsive to fluid replacement. Transoesophageal echocardiography (TEE) was carried out, as pulmonary arterial catheterization was considered too dangerous. A "white" thromboembolus was discovered in the right pulmonary artery. Embolectomy was successfully performed without extracorporeal circulation. Flow was completely restored in the main pulmonary artery, but only partially in the right branch. Oral anticoagulation was started postoperatively. It is concluded that TEE might be a very helpful technique to promptly diagnose acute pulmonary embolism; moreover, it could be an alternative to pulmonary angiography, especially in patients in a poor state.

Drug Hypersensitivity↗
PubMed1990

[Opening of a foramen ovale during liver transplantation. The value of transesophageal echocardiography].

A case is reported of a foramen ovale becoming patent during orthotopic liver transplantation (OLT). The patient had a hepatoma secondary to post-hepatitis cirrhosis. Monitoring included transesophageal echocardiography (TEE). A veno-venous shunt between the right femoral, portal and left axillary veins was used so as to maintain the venous return during portal and caval clamping. The patient's haemodynamic state remained quite stable throughout this period, and no vasoactive drug was required. Five min after graft reperfusion, pulmonary arterial pressure increased suddenly (mean PAP: 27 mmHg). TEE revealed paradoxical movements of the atrial septum. Colour coded Doppler ultrasound showed blood flowing from the right to the left atrium through a patent foramen ovale. Fifteen min later, mean PAP decreased (18 mmHg) and TEE no longer showed any flow between the two atria. Several studies have reported transient pulmonary hypertension after unclamping when the donor liver is reperfused. This could induce right ventricular failure, with transient inversion of the atrial pressure gradient, which, in turn, could result in a right-to-left shunt through a patent foramen ovale. TEE can monitor regional and overall left ventricular function as well as the atrial septum. This technique might therefore to be useful for cardiac monitoring during OLT.

Cardiomyopathies↗
PubMed1990

Clonidine-induced analgesia in postoperative patients: epidural versus intramuscular administration.

To compare the analgesic efficacy and plasma concentration of intramuscular (IM) versus epidural (EP) clonidine, 20 patients recovering from orthopedic or perineal surgery were randomly divided into two groups of ten. Clonidine (2 micrograms/kg) was administered epidurally in group 1 and intramuscularly in group 2. Analgesia was assessed using a visual analog scale (VAS) over a period of 6 h following clonidine administration. Venous blood samples were obtained at specific intervals for radioimmunoassay determination of plasma clonidine concentrations. The maximum reduction in VAS pain score was 78.5 +/- 20.6% in the EP group and 68.1 +/- 31.5% in the IM group (NS). Onset of analgesia was similar (within 15 min of injection), but duration tended to be longer after epidural than intramuscular administration (208 +/- 87 min vs. 168 +/- 95 min, mean +/- SD, P greater than 0.05). The peak plasma clonidine concentration after EP injection was 0.82 +/- 0.22 ng/ml and 1.02 +/- 0.76 ng/ml after IM injection. Hypotension, bradycardia, and drowsiness occurred with both methods of administration. None of these effects required treatment. Thus, in postoperative patients clonidine produces similar analgesia and side effects after parenteral or EP administration.

Adult↗
PubMed1990

Aortic surgery: effect of clonidine on intraoperative catecholaminergic and circulatory stability.

Twenty-eight patients presenting for aortic surgery were randomly assigned in a double-blind, placebo-controlled protocol to receive placebo (n = 14) or clonidine (4.7 +/- 1.2 micrograms.kg-1 po; n = 14), in addition to flunitrazepam 120 min before induction of anesthesia. Plasma catecholamines (CA) and hemodynamic variables were determined at 7 stages during surgery. In the placebo group, plasma epinephrine (E) and norepinephrine (NE) had risen twofold at skin closure compared to baseline (E: from 109 +/- 51 pg.ml-1 to 294 +/- 161 pg.ml-1; NE: from 658 +/- 226 to 1150 +/- 494 pg.ml-1). Plasma CA were significantly lower in the clonidine group (P less than 0.001 and 0.01 vs placebo for NE and E respectively). In both groups, similar directional changes were observed for the circulatory variables, upon aortic clamping and declamping. In the clonidine group, however, mean arterial pressure was lower at most stages (P less than 0.05 vs placebo); moreover, stroke volume index was greater in the clonidine group (P less than 0.05) upon declamping. This improved stability in the clonidine group was achieved with a halving in the number of anesthetic/circulatory interventions (P less than 0.05 vs placebo). Provided intravascular volume is adequate, clonidine suppresses the increase in plasma catecholamines induced by aortic surgery and improves circulatory stability, with a reduced number of anesthetic, circulatory adjustments.

Adult↗
PubMed1990

Comparison of the effects of fentanyl on respiratory mechanics under propofol or thiopental anaesthesia.

Twenty patients were randomly anaesthetized with either thiopental 5 mg/kg followed by a 15 mg/kg/h continuous infusion, or propofol 2.5 mg/kg followed by a 9 mg/kg/h continuous infusion, paralysed with vecuronium 0.1 mg/kg, intubated and ventilated with nitrous oxide 50% in oxygen. Fifteen minutes after induction, fentanyl 5 micrograms/kg was injected. Inspiratory tracheal pressure (PT), gas flow (V) and volume (V) were continuously measured while the lungs were inflated with a constant inspiratory flow ventilator. Respiratory compliance (Crs) and resistance (Rrs) were calculated from the regression of PT on V. In both groups Crs decreased following anaesthesia. Fentanyl injection elicited an increase in Rrs (from 1.04 +/- 0.70 to 1.63 +/- 0.92 kPa x l-1 x s) and a further decrease in Crs (from 0.55 +/- 0.30 to 0.42 +/- 0.10 l x kPa-1) in the thiopental group but not in the propofol group (Rrs: 1.26 +/- 0.69 to 1.08 +/- 0.44 kPa x l-1 x s, Crs: 0.49 +/- 0.11 to 0.48 +/- 0.13 l x kPa-1). These results suggest that the dose of propofol administered in this study may prevent fentanyl-induced bronchoconstriction.

Adult↗
PubMed1989

[Cervical epidural anesthesia in carotid artery surgery].

A series of 394 patients who underwent surgery of the carotid artery under cervical extradural anaesthesia is presented. With this technique the patient remains conscious throughout the operation, which facilitates neurological monitoring. Due to failure or complication, extradural anaesthesia was abandoned and replaced by general anaesthesia in 1.5 per cent of the cases. The mortality rate in this series was 2.3 per cent; in 2 out of 3 cases death was of neurological origin; 21 per cent of the patients had peroperative neurological accidents which, in 9 out of 10 cases, were due to a low cerebral blood flow rate during clamping. Thirty-five intra-arterial shunts (8.9 per cent) were installed, and none of these accidents was permanent. Twenty-five patients (6.3 per cent) had postoperative deficit which did not regress in 12 cases (3 per cent). The risk of peroperative neurological accident was significantly increased in patients with bilateral lesions of the vertebral arteries (x 3.5) or with occlusion of the contralateral carotid artery (x 4.5). Surgery of the carotid artery in conscious patients reveals a high incidence of ischaemic neurological events the reversibility of which is ensured by appropriate therapeutic procedures (arterial shunt, increase of brain perfusion pressure). Patients at risk of neurological accidents may benefit from cervical extradural anaesthesia.

Aged↗
PubMed1989

Evaluation of Doppler examination for diagnosis of catheter-related deep vein thrombosis.

The accuracy of Doppler examination was evaluated for the diagnosis of catheter-related venous thrombosis in 40 postoperative patients. Deep vein thrombosis was detected by venography in 15 patients and confirmed by the Doppler technique in a double blind study. Only one false-positive and one false-negative result were obtained with the Doppler technique. This technique appears to be valuable for the early diagnosis of catheter-related vein thrombosis, even in asymptomatic patients.

Catheterization, Central Venous↗
PubMed1989

[Comparison of blood pressure profiles with flunitrazepam/fentanyl/nitrous oxide vs cervical epidural anesthesia in surgery of the carotid artery].

A study was carried out to compare the evolution of arterial blood pressure during carotid endarterectomy performed under either general anaesthesia (GA) or cervical epidural anaesthesia (CEA). 20 patients were randomly assigned to two equal groups. In the CEA group, 15 ml of 0.375% bupivacaine and 150 micrograms fentanyl were injected into the epidural space at C7-D1 level. In the GA group, patients were anaesthetized with 0.2 mg.kg-1 flunitrazepam and 5 micrograms.kg-1 fentanyl; intubation was carried out using 0.08 mg.kg-1 vecuronium, and the patients were ventilated with a mixture of nitrous oxide and oxygen (50% of each). Further injections, every 30 min, of 2 micrograms.kg-1 fentanyl were given to the patients in group GA. Blood pressure was monitored continuously, up to 4 h postoperatively, with a radial arterial catheter. Per- or postoperative hypertension was defined as a rise in systolic arterial blood pressure (Pasys) over 180 mmHg for greater than 3 min; this was treated with 20 mg nifedipine intranasally (group CEA) or 100 micrograms fentanyl with 0.5 mg flunitrazepam with or without nifedipine (group GA). Per- or postoperative hypotension was defined as a fall in Pasys below 100 mmHg and or a 30% fall in mean arterial blood pressure for greater than 3 min; this was treated, in both groups, with an intravenous bolus of 3 mg ephedrine. Patients in group CEA experienced more frequent episodes of peroperative hypertension (8/2; p less than 0.02) and postoperative hypotension (5/1) than group GA.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Baroreceptor control after cervical epidural anesthesia in patients undergoing carotid artery surgery.

Baroreceptor (BR) reactivity was studied in 16 patients scheduled for carotid artery surgery performed under cervical epidural anesthesia with 0.375% bupivacaine (15 mL). In the first seven patients, BR reactivity was assessed by measurement of the slopes of the linear relationship between systolic arterial pressure (SAP) and the RR interval on the electrocardiogram. Alterations of blood pressure (BP) were produced using sequential intravenous (IV) doses of nitroglycerin (NTG; 100 to 200 micrograms) or phenylephrine (PHE; 100 to 200 micrograms), before and 30 minutes after epidural anesthesia. The changes in SAP and heart rate (HR) determined during the four phases of a Valsalva maneuver were evaluated in a second set of measurements before and after cervical epidural blockade. In nine additional patients, a third set of measurements studying BR reactivity after carotid clamping and unclamping was performed in order to assess the effect of carotid handling on BP control. Cervical epidural anesthesia induced moderate decreases in BP (SAP, 150 +/- 18 mmHg before cervical block, 143 +/- 27 mmHg after cervical block, P less than 0.05) and HR (RR, 812 +/- 120 ms before cervical block, 938 +/- 130 ms after cervical block, P less than 0.05). Cervical epidural anesthesia depressed BR reactivity during deactivation as assessed by the decrease in the BR slope after PHE injection (6.6 +/- 4.4 ms/mmHg before cervical block v 2.5 +/- 1.8 ms/mmHg after cervical block, P less than 0.01) and activation as assessed by the changes in SAP and HR during phases II and IV of the Valsalva maneuver.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Neuroleptanesthesia versus thoracic epidural anesthesia for abdominal aortic surgery.

The hemodynamic consequences of abdominal aortic surgery with infrarenal cross-clamping were studied in 21 patients randomized in two groups. In Group I (11 patients), neuroleptanesthesia was utilized, while Group II (10 patients) received thoracic epidural anesthesia at the T8-9 level. Hemodynamic measurements were performed using Swan-Ganz catheters during the surgical procedures in all patients, with special attention to the periods of clamping and unclamping of the abdominal aorta. The thoracic epidural anesthesia group was characterized by greater hemodynamic stability during surgery, while patients in the neuroleptanesthesia group had significant lability of blood pressure, heart rate, and cardiac index. Nevertheless, in the two groups of patients, it is suggested that cardiac function was unfitted to the tissue oxygen demand after unclamping of the aortic prosthesis because the saturation in oxygen of the mixed venous blood and an increase in arteriovenous difference in oxygen were documented. These results point out that, whatever the anesthesia technique, the critical period in abdominal surgery could be aortic unclamping.

Anesthesia, Epidural↗
PubMed1989

Prevention of tourniquet pain by spinal isobaric bupivacaine with clonidine.

In order to assess the effect of spinal clonidine on tourniquet pain, 30 patients scheduled to undergo orthopaedic surgery under spinal anaesthesia were allocated randomly to two groups. Patients in group I (n = 15) received 0.5% isobaric bupivacaine 15 mg plus isotonic saline 1 ml. Patients in group II (n = 15) received 0.5% bupivacaine 15 mg plus clonidine 1 ml (150 micrograms). Sensory block was evaluated by pinprick and motor block with Bromage's scale. The presence of clonidine significantly prolonged the duration of sensory and motor block. Three patients in group I, but none in group II, experienced tourniquet pain. Hypotension and bradycardia were not worsened by spinal clonidine. The use of clonidine may be a useful technique to augment bupivacaine spinal block.

Adult↗
PubMed1989

Postoperative analgesia with extradural clonidine.

The analgesic effect of extradural clonidine was evaluated in a double-blind study. In the recovery room, following orthopaedic or perineal surgery 20 ASA I and II patients were allocated randomly to two groups. The extradural clonidine (EC) group received clonidine 2 micrograms kg-1 in isotonic saline solution 15 micrograms ml-1. The extradural saline (ES) group received the equivalent volume of plain isotonic saline solution. Pain was evaluated by a visual analogue scale (VAS) at 15-min intervals for the first 2 h and subsequently at 30-min intervals for the following 4 h. Morphine 5 mg was given s.c. when patients complained of pain after extradural saline or clonidine. In the EC group, the mean (SD) maximum pain relief was 68.2 (24.1)% of the initial VAS score, but it was only 14.7 (25.2)% in the ES group. The mean duration of analgesia, before injection of morphine, was significantly longer in the EC group (210 (87) min) compared with the ES group (45 (27) min) (P less than 0.001). Drowsiness and moderate hypotension were observed in the EC group.

Adult↗
PubMed1989

Abnormalities in myocardial segmental wall motion during lumbar epidural anesthesia.

The effect of lumbar epidural anesthesia on myocardial wall motion was compared in two groups of patients using precordial two-dimensional echocardiography (2DE). All patients were scheduled to undergo lower abdominal or peripheral surgery. Group 1 included five healthy ASA PS 1 subjects and group 2 included 10 patients with coronary artery disease (CAD). In all patients 12.5 ml of 2% lidocaine HCl was injected into the lumbar epidural space, and systolic and diastolic blood pressures, and heart rate were continuously monitored. 2DE evaluation was performed before and at 10, 20, 30, and 60 min (T10-T60) after epidural lidocaine injection. The left ventricular wall was divided into 16 segments for parasternal long-axis, short-axis and apical four-chamber views. The wall motion of each segment was graded on a scale from 1 (dyskinesia) to 6 (hyperkinesia), with 5 representing normal motion. A decrease in segmental wall motion greater than or equal to 2 grades was considered indicative of ischemia. Plasma lidocaine and catecholamine levels were measured before and 10, 20, and 60 min after epidural lidocaine injection. Peak plasma lidocaine levels in groups 1 and 2 were 2.79 +/- 1.06 micrograms/ml (mean +/- SD) and 2.58 +/- 1.48 micrograms/ml at 10 min, respectively (NS). Plasma epinephrine and norepinephrine levels were unchanged from baseline. Systolic pressures decreased significantly in group 2 from T10 to T60. Diastolic pressure decreased significantly in the same group from T20 to T60, and in group 1 only at T10. Mean arterial pressure decreased significantly in both groups at T30, without change in heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗