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Biomedical subjects

P G Durand

Publications and source records attributed to P G Durand.

At least 19 recordsLinked to original sources
PubMed2002

[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↗
PubMed2001

[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↗
PubMed1999

[Anesthesia consultation in cardiovascular and thoracic surgery. A survey of patient and physician satisfaction].

OBJECTIVE: To assess the quality of the preadmission anaesthetic consultation prior to cardiovascular and thoracic surgery with a satisfaction inquiry. STUDY DESIGN: Prospective study with a questionnaire, extended over a period of two months. PERSONS: Patients and anaesthetists of the cardiothoracic surgical service. METHODS: The inquiry, which took place after completion of the consultation was achieved by a person non member of the staff. Anaesthetists were questioned on the medical content, its exhaustive character and its value for the patient's perioperative care. RESULTS: Out of the 273 patients included in the study, 121 agreed to answer the questionnaire. Participation in the study was more significant in older patients (58 +/- 20 vs 51 +/- 24 years) and following shorter waiting time (WT) [15 +/- 13 (0-60) vs 25 +/- 18 (0-66) min]. The duration of the consultation (DC) was not different between the two groups [29 +/- 12 (8-70) vs 31 +/- 14 (6-75) min]. However patients' participation increased when the DC exceeded by 0.6 the sum of DC and WT [DC > 0.6 (DC + WT)]. The analogic score (AS) assessing reduction in preoperative anxiety was 8.4 +/- 1.5 (2-10). Finally, 108 patients out of 121 considered to have been well informed about the anaesthetic [AS = 8.7 +/- 1.2 (4-10)], 113 considered the preadmission consultation as a useful procedure [AS = 8.6 +/- 1.5 (2-10)]) and for 41 a personalized follow-up by the same anaesthetist was valuable. Only three operations had to be postponed the day before surgery. One third of the anaesthetists considered that the consultation improved the clinical and therapeutic management of the patients. CONCLUSION: This inquiry showed that the preadmission anaesthesia consultation was considered as benefitful by patients and anaesthetists. However the participation of patients in this study was poor. Subsequently to the inquiry information forms have been produced and handed to the patient prior to the consultation.

Adolescent↗
PubMed1999

Influence of temperature on tracheal tube cuff pressure during cardiac surgery.

BACKGROUND: Lateral wall pressure may cause tracheal injury by affecting tracheal capillary blood flow. Damage to the trachea is less severe when lateral wall pressure exerted by the endotracheal tube cuff does not exceed the mean capillary perfusion pressure of the mucosa. The purpose of this study was to determine the effects of hypothermic and normothermic cardiopulmonary bypass (CPB) on tracheal tube cuff pressure dynamics. METHODS: Twenty-two patients were studied during normothermic CPB (pulmonary artery blood temperature in the CPB period between 36 and 35 degrees C), and 22 patients during hypothermic CPB (pulmonary artery temperature in the CPB period between 32 and 28 degrees C). A Mallinckrodt Medical Lo-Contour Murphy tracheal tube, with high-volume, low-pressure cuff was used without lubricant. Intracuff pressure (ITCP) was recorded at end-expiration before, during and after cardiopulmonary bypass. RESULTS: ITCP measurements were different between groups during CPB at aortic cross-clamping (13.9 +/- 0.8 mmHg in the normothermic group versus 11.3 +/- 0.4 mmHg in the hypothermic group, P < 0.05), and respectively during CPB after aortic declamping (15.3 +/- 0.8 mmHg and 12.6 +/- 0.8 mmHg, P < 0.05) and after CPB at the end of surgery (16.8 +/- 0.7 mmHg and 18.6 +/- 0.3 mmHg, P < 0.05). CONCLUSION: We conclude that the ITCP is higher in normothermic CPB than in hypothermic CPB; however, the clinical significance of this observation needs further investigation.

Aged↗
PubMed1999

Comparison of two semicontinuous cardiac output pulmonary artery catheters after valvular surgery.

OBJECTIVE: To compare semicontinuous cardiac output (CCO) with bolus cardiac output (BCO), in the immediate postoperative period after valvular surgery, under hypothermic cardiopulmonary bypass with two CCO pulmonary artery catheters, based on the pulsed warm thermodilution technique, i.e., Opti-Q from Abbott or IntelliCath from Baxter-Edwards (Abbott and Baxter groups, respectively). DESIGN: Prospective study. SETTING: University hospital. PATIENTS: Forty-four adult patients scheduled for mitral and/or aortic valve surgery were randomized into two groups. Tricuspid or pulmonary valvulopathy diagnosed by echocardiography was excluded. INTERVENTIONS: Cardiac output was measured every 20 mins during the 3 postoperative hrs. BCO was the mean of three boluses (10 mL) of an ice-cold saline solution injected within 3 secs. CCO was the mean of two CCO values obtained in normal mode immediately before and after BCO measurements. MEASUREMENTS AND MAIN RESULTS: Two groups of 22 patients underwent 198 pairs of cardiac output measurements. The mean difference or bias was calculated as the difference between BCO and CCO, and precision was the SD of the mean bias. The limits of agreement were defined as bias +/- 2 SD. A two-sample Wilcoxon's test was used for comparison of bias and precision in sinus and non-sinus rhythm, and stable and unstable mean arterial pressure in each group and between the two pulmonary artery catheters. The coefficient of correlation was also calculated. Bias +/- precision was 0.066+/-0.526 L/min, r2 = .83, for the Abbott group, and 0.015+/-0.490 L/min, r2 = .85 (not significant), for the Baxter group. There was no significant difference within and between groups for bias and precision in sinus and non-sinus rhythm, nor in stable and unstable mean arterial pressure. CONCLUSIONS: This study, during the immediate postoperative period in valvular surgery under hypothermic cardiopulmonary bypass, showed a satisfactory correlation between CCO and BCO with the two systems.

Aged↗
PubMed1998

Brachial plexus injury during cardiac catheterisation in children. Report of two cases.

The arm is particularly vulnerable to neurological injury, due to the intimate anatomical relationship between the brachial plexus and the traction zones. Severe injuries of the brachial plexus can be caused by compression, traction or laceration. Fortunately, many deficits are superficial and permanent neurovascular deficits are rare. Nevertheless, it is important to identify the probable cause of the injury since the prognosis for recovery directly depends on the underlying nature of the neurological deficit. Two anaesthetised children who suffered brachial plexus injury during cardiac catheterisation are reported. The first, with Ebstein's anomaly and significant pulmonary valve stenosis, presented, after the procedure, with a right arm motor deficit with proximal predominance. The second patient, with tetralogy of Fallot and pulmonary atresia, presented difficulty in left arm abduction and external rotation on awakening. The risk factors for brachial plexus lesions during anaesthesia are discussed. These include improper positioning, anaesthetic agents, extreme variations of body mass index and anatomical anomalies. Prevention, evolution and treatment of the brachial plexus injury are also considered. With proper care by the cardio-radiologist and anaesthesiologist the frequency of this injury can be reduced.

Adolescent↗
PubMed1997

Predictive factors for usefulness of fiberoptic pulmonary artery catheter for continuous oxygen saturation in mixed venous blood monitoring in cardiac surgery.

The main goal of this prospective study was to identify among cardiac surgery patients, usually monitored through a standard pulmonary artery catheter (PAC), those in whom a fiberoptic catheter oximeter to measure oxygen saturation in mixed venous blood (SVO2 PAC) would be most useful. Data from 286 patients who underwent coronary artery bypass graft (50%) or valvular surgery were recorded, including ASA physical status, New York Heart Association (NYHA) classification, and Parsonnet score (PS). Hemodynamic events and SVO2 changes were collected intra- and postoperatively until weaning from mechanical ventilation. The anesthesiologist in charge graded the usefulness of SVO2 PAC, and another anesthesiologist carried out a blindly controlled overall evaluation. Usefulness was defined as the presence of a change in therapeutic maneuver triggered solely by continuous SVO2 data that would not have occurred based on other routine parameters. SVO2 was also considered useful if earlier recognition of significant adverse events occurred. SVO2 PAC was useful in 57% of the patients. Independent predictive factors (multivariate analysis) for the perioperative usefulness of SVO2 in the whole population consisted of ASA class > or = 4 (P < 10(-5); relative risk [RR] 1.78, 1.51-2.07), mitral surgery (P < 10(-4); RR 1.72, 1.4-2.02), and NYHA score > or = 3 (P < 0.01; RR 1.66, 1.35-2.05). Independent predictive factors for the perioperative usefulness of SVO2 in the coronary artery bypass graft population were NYHA score > or = 3 (P < 10(-5); RR 1.90, 1.42-2.55) and ASA class > or = 4 (P < 0.01; RR 1.99, 1.51-2.63). The presence of three stenosed coronary arteries showed borderline significance (P < 0.06). Independent predictive factors for perioperative usefulness of SVO2 in the valvular population were mitral pathology (P < 10(-5)) and ASA class > or = 4 (P < 0.01). The receiver operator characteristic curve assessed the predictivity of the PS. SVO2 PAC was more useful in the group of patients with the greatest severity of illness (PS in useful group 17.0 +/- 10.3; in nonuseful group 8.7 +/- 6.6; P < 10(-4)). Intensive care unit duration and hospital stay in the useful group was prolonged compared with the nonuseful group. Similarly, morbidity was frequent in the useful group, although it was not always significantly different from the nonuseful group according to the type of complications. Mortality was comparable in the groups despite their different degree of illness and was reduced when taking into account the predictive and observed mortality provided by the PS. This study defined independent preoperative factors associated with SVO2 PAC monitoring and proposed a cutoff point above which SVO2 may be useful.

Aged↗
PubMed1994

Relationship between oxygen uptake and mixed venous oxygen saturation in the immediate postoperative period.

BACKGROUND: During muscular exercise, a negative correlation has been demonstrated between the value of mixed venous oxygen saturation (SvO2) and the level of muscular work, expressed at each level as the ratio of oxygen uptake (VO2) to each subject's maximal oxygen uptake (VO2max). Because the immediate postoperative period is associated with an increase in whole body oxygen demand, and in this regard resembles the effects of muscular exercise, a similar correlation may exist during this period. METHODS: VO2max was determined in 11 patients 3-5 days before coronary artery bypass surgery. During the first 2 postoperative h, VO2 and SvO2 were monitored. VO2 was measured by indirect calorimetry and SvO2 by a fiberoptic pulmonary arterial catheter. RESULTS: The highest postoperative value of VO2 was most often associated with visible shivering and ranged among patients from 19% to 53% of preoperatively measured VO2max. There was a highly significant negative correlation between SvO2 and the ratio VO2/VO2max. This correlation was observed when data were examined collectively (136 simultaneous determinations of the two variables) and at the individual level (10-18 determinations for each patient). The slopes and the y intercepts of individual lines of correlation were within a narrow range. CONCLUSIONS: During the first 2 postoperative h after coronary artery bypass surgery, VO2 rarely exceeds 50% of preoperative VO2max. Assuming a stable state of myocardial function, SvO2 measurement may provide an indirect means of assessment of the "exercise test" imposed on patients recovering from general anesthesia.

Aged↗
PubMed1994

Effect of cardiopulmonary bypass on plasma concentrations of diltiazem and its two active metabolites.

Diltiazem is often used to prevent myocardial ischaemia during the perioperative period of coronary artery bypass surgery. The purpose of this study was to investigate the effect of cardiopulmonary bypass (CPB) on plasma concentrations of diltiazem and of its two main and active metabolites (N-monodemethyldiltiazem (N-desmethyldiltiazem) and desacetyldiltiazem). The patients were administered their usual treatment during the preoperative days. The last dose was administered immediately before anaesthesia. At the onset of CPB, a significant decrease in the plasma concentrations of diltiazem and its metabolites was observed, whereas the variation was slight and not significant when the plasma concentrations were corrected for haemodilution. These results confirm that the decrease observed at the initiation of the bypass procedure can be ascribed to the haemodilution induced by the CPB. During CPB, the concentrations of diltiazem and its metabolites remained constant suggesting that the rate of metabolism and excretion of the drug was altered during the bypass procedure. At the end of CPB, there was no increase of drug plasma concentrations suggesting that no redistribution of diltiazem from tissues to plasma occurred. Furthermore, this study shows that only 33% of subjects have therapeutic levels of diltiazem before anaesthesia, and that all subjects have subtherapeutic levels during and after the CPB. These results suggest that a higher chronic oral dose of the drug should be given in patients undergoing cardiac surgery with CPB.

Aged↗
PubMed1994

[Automatic implantable defibrillators; subdiaphragmatic insertion].

Although the material and techniques of implantation of the electrodes of implantable defibrillators have been improved, the abdominal implantation of the generator remains widely used as described by Mirowski in 1980. Despite a progressive reduction in their size, the generators remain bulky and a source of local complications. The risks and discomfort of implantation in the abdominal wall led the authors to try subdiaphragmatic implantation in 22 patients. There was no morbidity with perfect healing in all 22 cases. The mean follow-up period was 11 months. The patients felt very comfortable, a significant advance with respect to abdominal implantations.

Adolescent↗
PubMed1993

[Plasma concentrations of diltiazem and its metabolites in coronary surgery: relation with preoperative treatment].

Preoperative oral administration of calcium channel blocking agents has been found ineffective to prevent perioperative myocardial ischaemia. Our hypothesis was that low plasma concentrations may account for this inefficiency. Twenty-three male patients, scheduled for surgical myocardial revascularisation, were administered their usual anti-anginal treatment, including 180 to 360 mg of diltiazem since more than one week. The usual dosage was given at 8.00 p.m. on the day before surgery. On the morning of surgery, after withdrawal of a first blood sample, 60 mg of diltiazem were administered per month before the induction of anaesthesia. The anaesthesia was obtained with fentanyl, midazolam or flunitrazepam, pancuronium and isoflurane as required. The cardiopulmonary bypass (CPB) was associated with total haemodilution with Ringer's Lactate and a membrane oxygenator. A second blood sample was withdrawn after CPB. Plasma concentrations of diltiazem and its two active metabolites, N-monodemethyldiltiazem (MA) and desacetyldiltiazem (M1), were assessed by HPLC. Plasma diltiazem concentrations decreased from 78 +/- 66 (mean +/- SD) to 51 +/- 42 micrograms.l-1 (p < 0.05) with wide individual variations. These concentrations were under therapeutic levels in 18 out of 23 patients before (p < 0.05) with wide individual variations. These concentrations were under therapeutic levels in 18 out of 23 patients before induction and in 22 patients after CPB. The metabolite/diltiazem ratios remained constant. A dosage-plasma concentration relationship was observed preoperatively with diltiazem and MA. It is concluded that plasma concentrations of diltiazem should be optimized preoperatively in order to prevent myocardial ischaemia.

Aged↗
PubMed1993

[A comparison of 3.5% dextran 40 and 4% albumin used as volume expansion solutions following heart surgery. Effects on the hemodynamic parameters and the oncotic colloidal pressure].

Dextran 40 (3.5%), a synthetic colloid solution used as a volaemic expander was compared to albumin 4% in 30 patients (15 in each group) during the first twenty hours after cardiac surgery. The patients were administered 500-600 ml.m-2 either dextran 40 or albumin at a rate of 10-12 ml.kg-1 x h-1 between 2nd and 4th postoperative hour. In the two groups, heart rate and mean arterial pressure did not change significantly but left and right filling pressures and cardiac index increased similarly. Colloid oncotic pressure and haemoglobin varied in the same way in the two groups. Proteinemia and albuminaemia were increased significantly in the albumin group during all the study. Diuresis was not different in the two groups. No side effect was observed. Dextran 40 was efficient and could be used as a volaemic expander after cardiac surgery.

Adolescent↗
PubMed1993

[Problems posed by calcium antagonists and anesthesia: pharmacology, interactions, indications].

Calcium-channel inhibitors are widely used in therapeutics. Many patients administered calcium channel inhibitors undergo surgical procedures and the cardiologists or the anaesthesiologists are concerned with pharmacological interactions with anaesthetic agents such as halogenated gases. The combination of calcium channel inhibitors and halogenated anaesthetics may exert an additive effect on myocardial depression, conduction disturbances and arterial vasodilatation. The continuation of oral calcium channel inhibitors until the day of surgery is recommended provided the use of enflurane is restrained. Calcium-channel inhibitors such as dihydropyridines are currently administered intravenously to control intra and postoperative arterial hypertension while verapamil and diltiazem are used to treat supraventricular arrhythmias and myocardial ischaemic episodes. In patients with cardiac disease, haemodynamic monitoring may allow to anticipate or to treat episodes of cardiac dysfunction associated with I.V. calcium-channel inhibitors during the perioperative period.

Anesthetics↗
PubMed1992

[Vascular effects of urapidil administrated during extracorporeal circulation].

Urapidil exerts a combined central sympathetic and peripheral alpha-1 adrenergic receptor inhibition. Urapidil induces arterial vasodilation but its effects on venous capacitance are more difficult to assess. During cardiopulmonary bypass with constant perfusion index (2.4 l.min-1 x m-2) total peripheral resistance varies similarly as to arterial pressure and, as the apparatus venous reservoir is filled continuously by simple gravity from the right atrium, a decrease in venous blood reservoir level reflects an increased venous capacitance. Twenty-six patients undergoing cardiac surgery were anaesthetized with fentanyl and midazolam and randomly assigned to one of two groups. During normothermic cardiopulmonary bypass, group 1 was administered i.v. urapidil 12.5 mg and group 2 a placebo. In group 1, arterial pressure decreased by 33 +/- 14% (mean +/- SD) at the second minute while total peripheral resistance decreased from 1,384 +/- 255 to 927 +/- 193 dyn.s.cm-5. Then this two parameters regained group 2 values after the eighth minute. Reservoir blood level was lower in group 1 than in group 2 from the second to the eight minute (p < 0.05) with maximum effect at 7 minutes. It is concluded that urapidil exerts arterial and venous dilation. Its arterial effects seem greater during normothermic cardiopulmonary bypass than in normal conditions and its maximum venous effects seem to occur after its maximum arterial effects. The short duration of action may be due to the small dose administered.

Aged↗
PubMed1991

Calcium-channel blockers and anaesthesia.

Verapamil was the first calcium-channel blocker (CCB). It has been used since 1962 in Europe then in Japan for its antiarrhythmic and coronary vasodilator effects. The CCB have become prominent cardiovascular drugs during the last 15 years. Many experimental and clinical studies have defined their mechanism of action, the effects of new drugs in this therapeutic class, and their indications and interactions with other drugs. Due to the large number of patients treated with CCB it is important for the anaesthetist to know the general and specific problems involved during the perioperative period, the interactions with anaesthetics and the practical use of these drugs.

Anesthetics↗
PubMed1990

[Beta blockers and anesthesia].

Beta-adrenoceptor antagonists (BB) demonstrate a competitive antagonism with endogenous catecholamines. Beta-1 receptor blockade mediates the depressive action on contractility, heart rate and atrio-ventricular conduction. Beta-2 receptor blockade mediates vascular, bronchial and uterine smooth muscle constriction. BB with beta-1 selective and intrinsec sympathomimetic activity do not increase systemic vascular resistance. BB are mostly used to treat ischaemic heart disease, hypertension and arrhythmias. Bradycardia, hypotension and bronchospasm are the main hazards in BB treated patients undergoing anaesthesia. However giving BB with premedication to patients taking usely this treatment allows better perioperative haemodynamic stability and avoids rebound effect. Experimentally, oxprenolol reverses regional dysfunction in ischaemic myocardium under halothane anaesthesia. During and after anaesthesia, intravenous (i.v.) BB must be used with caution to treat hypertension associated with tachycardia. In controlled hypotension, i.v. BB potentialise other agents. In phaechromocytoma surgery, alpha-blocking drugs are essential but additional BB can control tachycardia successfully. In coronary artery bypass surgery, giving BB prior to induction decreases cardiac enzymes serum levels. Esmolol, a new ultra-short-acting BB, would control perioperative tachycardia and hypertension without risk of prolonged cardiac depression.

Adrenergic beta-Antagonists↗