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Biomedical subjects

J J Lehot

Publications and source records attributed to J J Lehot.

At least 19 recordsLinked to original sources

[What can be expected from off-pump coronary artery surgery?].

Coronary artery bypass surgery with beating heart (off-pump) has become more common in the last ten years allowing seven randomized studies with at least 60 patients, comparing off-pump and on-pump coronary bypass. Anaesthesia, monitoring and haemodynamic complications are described. Randomized studies concluded to less elevation of biochemical markers of myocardial and renal injury, less hydric inflation, less cerebral microemboli, reduction of homologous blood transfusions, of hospital stay and global costs. However in low risk patients no reduction in myocardial infarction, atrial fibrillation, stroke, acute renal failure, early reoperation, surgical site infection and mortality were observed. Non-randomized studies suggest a benefit in stroke and mortality in elderly patients but the possibility of incomplete revascularization remains.

Anesthesia↗

[Perioperative administration of betablockers: a practice survey].

OBJECTIVES: To evaluate the anaesthesiologists' attitude concerning the perioperative administration of betablockers (BB), especially prophylactic BB, in order to prevent postoperative cardiac complications. METHODS: A questionnaire including 20 items was sent to 700 anaesthesiologists of 4 French departments (Ain, Isere, Loire et Rhone). RESULTS: The response rate was 30%. Eighty-eight percent of respondents prescribed the BB with the premedication, on the day of the surgery in patients who were on regular BB. Before major surgery, 37% percent of respondents always or usually introduced prophylactic BB in patients with high cardiac risk. Atenolol was the drug of choice for 68% of perioperative BB users. Seventy-one percent of anaesthesiologists using prophylactic BB asked for a cardiologic opinion before starting BB therapy. CONCLUSION: In practice, anaesthesiologists continued BB during the perioperative period in patients who were on chronic treatment with BB. However, prophylactic perioperative administration of BB in patients with high cardiac risk is still inadequate and dependent on a cardiologic opinion.

Adrenergic beta-Antagonists↗

[To understand blood pressure and heart rate variability].

OBJECTIVES: To review current data on the heart rate and blood pressure variability. DATA SOURCES: Search through Medline databases of articles in french or english. DATA SELECTION: Original articles and case reports were selected according to their quality and main advances. The articles were analysed in order to obtain current data about the methods of study and clinical application of blood pressure and heart rate variability. DATA SYNTHESIS: Various regulatory systems in the cardiovascular system play crucial roles in controlling and assuring adequate perfusion of the peripheral tissues. Among them the baroreceptor reflex is the most important regulatory mechanism in the short-term control of the heart rate and blood pressure, and operates through the autonomic nervous system. The gain of the cardiac baroreflex further referred to, as baroreflex sensitivity is an interesting way to study this system. Unfortunately, with our current knowledge, it is not possible to predict the instantaneous output of the baroreceptor in response to instantaneous changes in input within a frequency range of physiological importance. The fast Fourier transform can describe variables as the sum of elementary oscillatory components and it has been established as practical clinical methods for detecting abnormalities in cardiovascular control. A time-frequency distribution provides an indication of how the spectral energy distribution varies with time and it is an interesting tool in non-stationary data. One of the major motivations behind spectral analysis is the hope that the combination of time-domain and frequency-domain analyses will provide dynamical informations about the relation between blood pressure and heart rate.

Animals↗

[Anaphylaxis after rocuronium: advantage of blood tests for early diagnosis].

A 56-year-old patient was scheduled for coronary artery bypass surgery, because of a severe coronary artery disease. Soon after induction of anaesthesia, he rapidly developed a cardiovascular collapse with bronchospasm and rash. Specific immunoglobulin E and tryptase measurements supported the diagnosis of grade III anaphylactic shock due to rocuronium bromide. A few days later, a general anaesthesia was administered without muscle relaxant and was uneventful.

Anaphylaxis↗

[Antibiotic prophylaxis in cardiac surgery: practice patterns].

OBJECTIVE: To assess the prescription patterns in French and foreign centres for antibiotic prophylaxis in cardiac surgery. MATERIAL AND METHODS: Phone and written surveys concerned 64 French and 70 foreign centres. It focused on the first injection, the duration of treatment and the recommended agents. RESULTS: 87% of the French centres and 67% of the foreign centres answered the questionnaire. The first injection took place at anaesthesia induction in all French centres but during administration of premedication in 11% of foreign centres (p < 0.05). The duration of prophylaxis was restricted to the intraoperative period only in 20% and 15% of centres, respectively (ns), as specified by the recommendations. No French centres carried on the antibiotics more than 48 h versus 11% of foreign centres (p < 0.05). Cephalosporines of the second generation were prescribed in 84 and 49% of centres, respectively (p < 0.05). The combination of two antibiotics was less frequent in France than in foreign countries (5 versus 17%, p < 0.01). In absence of betalactamin allergy glycopeptides were not utilized in France versus 8% in foreign countries (p < 0.05). In case of allergy vancomycin was used in 66% of French and 42% of foreign centres. CONCLUSION: The French recommendations may have influenced favourably the antibiotic choice but the prophylaxis duration was too long in most of the non French European centres.

Antibiotic Prophylaxis↗

[Fulminant mediastinitis from Streptococcus pneumoniae following cardiac surgery].

A 62-year-old patient was scheduled for coronary artery bypass surgery because of tritroncular coronary artery disease. The early postoperative period was uncomplicated until the 10th postoperative day when purulent fluid appeared from the sternal wound. Cultures of blood, wound and mediastinal tissues yielded Streptococcus pneumoniae with decreased susceptibility to penicillin G. Despite prompt surgical debridement and appropriate antibiotics, a septic shock with multiorgan failure occurred and the patient died on the 19th postoperative day. Although Streptococcus pneumoniae is uncommonly implicated in postoperative mediatinitis, it frequently leads to multiple organ failure and death.

Adult↗

[Use of midazolam in postoperative sedation of patients with multiple organ failure treated with hemodiafiltration. Clinical study and pharmacokinetics].

OBJECTIVES: Evaluate the risk of accumulation of midazolam and conjugated 1-hydroxy-midazolam in high-risk ICU patients treated by continuous veno-venous haemofiltration. STUDY DESIGN: A prospective pharmocokinetic and clinical evaluation in 11 patients, with hepatic and renal failure. METHODS: Midazolam and metabolites were dosed in plasma and ultratiltration liquid by chromatography. Sedation was assessed by a simplified Ramsay score (EDS) with 4 levels. RESULTS: The mean duration of continuous infusion was 11 +/- 6 days. Peak plasma levels were over 150 ng ml-1 during the first 3 days, but normalized after that, only by drug adjustment based on scoring and clinical observation. There was no progressive accumulation of OH-midazolam, in spite of high levels (> 1000 ng ml-1). The Sieving coefficient (S) was 0.11 +/- 0.10 and 0.44 +/- 0.15 for midazolam and conjugated OH-midazolam respectively. A significant clearance (9.6 +/- 1.9 ml min-1) was observed for the conjugated products. T 1/2 beta was 11 h and was correlated with the mean time of recovery. A significant correlation was found between sedation score and both midazolam (r = 0.47) and OH-midazolam (r = 0.32). CONCLUSION: OH-midazolam risk of accumulation and significant clearance by haemodiafiltration should be taken into account in the drug adjustment in patients treated by continuous veno-venous haemofiltration.

Adjuvants, Anesthesia↗

Effect of diaspirin cross-linked haemoglobin (DCLHb) on mean arterial pressure during cardiopulmonary bypass in swine.

Diaspirin cross-linked haemoglobin (DCLHb) is a haemoglobin-based oxygen carrier which had been proposed as a resuscitative solution to replace red cell transfusion in many clinical situations. The present study was designed to evaluate the effect of different volumes of DCLHb 10% (1, 5 and 10 mL kg-1) on the cardiovascular system during cardiopulmonary bypass (CPB), and to determine the effect of DCLHb (18 mL kg-1) when added directly to the CPB prime in anaesthetized swine. DCLHb, when used as a priming solution, induced a significant increase (around 20%) in mean arterial pressure (MAP), which persisted during the entire period of CPB (P < 0.05) as compared with controls. Administration of increasing doses of DCLHb during the time course of CPB resulted in a progressive increase in MAP (P < 0.05), suggesting a linear dose-response relationship. Nicardipine, a calcium channel blocker, returned MAP to baseline. Finally, weaning of CPB was easier in animals that received DCLHb, thereby suggesting a potential protective effect of free haemoglobin in this particular clinical situation.

Animals↗

Pharmacological preconditioning: comparison of desflurane, sevoflurane, isoflurane and halothane in rabbit myocardium.

BACKGROUND: Recent investigations showed that isoflurane can induce pharmacological preconditioning. The present study aimed to compare the potency of four different halogenated anaesthetics to induce preconditioning. METHODS: Anaesthetized open-chest rabbits underwent 30 min of coronary artery occlusion followed by 3 h of reperfusion. Before this, rabbits were randomized into one of five groups and underwent a treatment period consisting of either no intervention for 45 min (control; n = 10), or 30 min of 1 MAC halogenated anaesthetic inhalation followed by 15 min of washout. End-tidal concentrations of halogenated agents were 3.7% for sevoflurane (n = 11), 1.4% for halothane (n = 9), 2.0% for isoflurane (n = 11), and 8.9% for desflurane (n = 11). Area at risk and infarct size were assessed by blue dye injection and tetrazolium chloride staining. RESULTS: Mean (SD) infarct size was 54 (18)% of the risk area in untreated controls and 40 (18)% in the sevoflurane group (P > 0.05, ns). In contrast, mean infarct size was significantly smaller in the halothane, isoflurane, and desflurane groups: 26 (18)%, 32 (18)% and 16 (17)%, respectively (P < 0.05 vs control). CONCLUSIONS: Halothane, isoflurane and desflurane induced pharmacological preconditioning, whereas sevoflurane had no significant effect. In this preparation, desflurane was the most effective agent at preconditioning the myocardium against ischaemia.

Anesthetics, Inhalation↗

Cardiac surgery with cardiopulmonary bypass in patients with type II heparin-induced thrombocytopenia.

BACKGROUND: The use of cardiopulmonary bypass (CPB) in patients with a history of type II heparin-induced thrombocytopenia (HIT) may be associated with complications related to their anticoagulation management. METHODS: Between January 1997 and December 1999, among 4,850 adults patients who underwent cardiac surgery in our institution, 10 patients presented with preoperative type II HIT. In 4 patients, anticoagulation during CPB was achieved with danaparoid sodium. In 6 other patients, heparin sodium was used after pretreatment with epoprostenol sodium. RESULTS: No significant change in platelet count occurred in any patient. No intraoperative thrombotic complication was encountered. Total postoperative chest drainage ranged from 250 to 1,100 ml in patients pretreated with epoprostenol and 1,700 to 2,470 ml in patients who received danaparoid sodium during CPB (p < 0.05, Mann-Whitney U test). CONCLUSIONS: During CPB, inhibition of platelet aggregation by prostacyclin may be a safe anticoagulation approach in patients with type II HIT.

Aged↗

Safety of oral nicorandil before coronary artery bypass graft surgery.

Nicorandil is a K(ATP) channel opener used to treat angina. It is cardioprotective and a vasodilator. We conducted a prospective, randomized, double-blind, placebo-controlled study to assess oral nicorandil in patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB). Twenty-two patients received nicorandil (10 mg twice a day) and 23 patients received placebo. Haemodynamic data were recorded before induction of anaesthesia (T0), 5 and 20 min after starting mechanical ventilation (T1, T2), before aortic cannulation (T3), after 30 min of CPB (T4), 10 min after CPB (T5) and after 3, 8 and 18 h in the intensive care unit (T6, T7, T8). Serum proteins (creatine kinase metabolite and cardiac troponin I) were measured before and 8 and 18 h after surgery. Haemodynamic values did not differ between the two groups. There was no tachycardia during the study, no significant difference in hypotensive episodes, ST segment changes and no changes in cardiac enzymes. Myocardial infarction after surgery was similar in the two groups. Vasoactive therapy was similar in the two groups. Nicorandil can be continued safely up to premedication without deleterious haemodynamic consequences, but a myocardial protective effect of nicorandil in CABG surgery was not found.

Administration, Oral↗

[Anesthesia for carotid endarterectomy].

Carotid endarterectomy (CE) is among the most common vascular procedures. Recent studies have examined indications for CE and the usefulness of multiple vascular procedures, and have compared general and locoregional anesthesia. Randomized prospective trials have confirmed that the efficacy of CE exceeds 70% in patients experiencing a transient ischemic attack (TIA) with an ipsilateral stenotic carotid lesion. When both carotid surgery and coronary revascularization are indicated, CE can be performed two weeks before or concurrent with coronary artery bypass. The greatest risk in CE is of neurological complications (usually < 6%); the risk of myocardial infarction (MI) is < 4%. General anesthesia is most comfortable for the patient and the surgeon. Barbiturates, opiates and isoflurane are widely employed. Cerebral monitoring involves residual pressure after clamping, although that approach is unreliable. Other forms of hemodynamic (cerebral flow with 133Xe, transcranial Doppler, jugular SvO2, conjunctival PO2) and electrical monitoring (EEG, somatosensory evoked potentials) are often unavailable, are expensive or require trained personnel. Locoregional anesthesia (cervical nerve block or cervical epidural anesthesia) can be monitored more reliably, allows therapeutic maneuvers such as carotid unclamping, placement of an intracarotid stent, increasing of arterial pressure to be carried out. Regional anesthesia decreases the incidence of intraluminal shunts. Blood pressure and heart rate are higher during cervical block than during general anesthesia, but hypertension is more common during general anesthesia. A randomized controlled trial comparing general anesthesia and cervical block found no significant differences in mortality, MI or TIA. Regional anesthesia is more cost-effective, given that less intensive care and shorter hospital stays are required.

Anesthesia↗