Persistent left superior vena cava diagnosed by transesophageal echocardiography.
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Aged↗
Biomedical subjects
L Delaunay
Publications and source records attributed to L Delaunay.
Partial reversal of the effects of extradural clonidine by oral yohimbine in postoperative patients.
Extradural clonidine produces analgesia, with sedation, hypotension and bradycardia, in postoperative patients. This study assessed if oral yohimbine would reverse these side effects. We studied 30 ASA I-II patients undergoing orthopaedic surgery. After operation they were allocated randomly to three groups to receive placebo, extradural clonidine 450 micrograms or extradural clonidine 450 micrograms plus oral yohimbine 16 mg. Pain score was measured on a visual analogue scale (VAS); sedation was assessed on a simple scale graded from 0 (awake and alert) to 3 (deeply sedated, awakening after tactile stimulations) and heart rate and arterial pressure were monitored for 5 h. Yohimbine reversed the sedation induced by extradural clonidine, but also shortened the duration of analgesia (31 (SD 15) min, 186 (72) min and 126 (52) min in the placebo, extradural clonidine and extradural clonidine+yohimbine groups, respectively) (P < 0.05), and did not reduce the hypotension and bradycardia related to clonidine administration. These results suggest that alpha 2 adrenoceptors are mediators of the sedation induced by clonidine and that the haemodynamic effects are not related to stimulation of supraspinal alpha 2 receptors.
Administration, Oral↗
Clonidine comparably decreases the thermoregulatory thresholds for vasoconstriction and shivering in humans.
BACKGROUND: Clonidine stops postoperative shivering, but its underlying mechanism of action is unknown. Clonidine may impair central control of thermoregulation or act on peripheral receptors. Accordingly, the authors tested the hypothesis that clonidine reduces both the vasoconstriction and shivering thresholds, a pattern consistent with central thermoregulatory impairment. METHODS: Seven healthy volunteers participated in the study. Thermoregulatory vasoconstriction was evaluated using forearm minus fingertip, skin-temperature gradients; values exceeding 4 degrees C were considered to be significant vasoconstriction. Systemic oxygen consumption (VO2) was measured with a canopy system. In addition, shivering was qualitatively evaluated using a simple scale, graduated from 0 (no shivering) to 2 (intense shivering). The tympanic membrane temperatures triggering significant vasoconstriction and grade 1 shivering were considered to be the thresholds for the two thermoregulatory responses. Measurements were performed after a 10-min steady state period and during cooling by central venous infusion of Ringer's lactate solution at 4 degrees C. Each subject was evaluated at two sessions, separated by at least 48 h. They were randomly and blindly assigned to received either an intravenous bolus of 75 micrograms clonidine or a placebo before cooling. When the shivering score equaled 2, 75 micrograms clonidine was injected intravenously, and repeated if necessary, to completely stop shivering.
Adult↗
[Patient-controlled analgesia: effect of adding continuous infusion of morphine].
This double blind study aimed to assess the effects of a continuous intravenous (i.v.) infusion of morphine added to an intermittent bolus patient controlled analgesia on morphine demand and related side-effects. Patients scheduled for abdominal and thoracic surgery (ASA 2 or 3) were randomly allocated postoperatively to three groups (n = 10 each): group 1 were given i.v. boluses of 2 mg of morphine (lockout interval = 15 min); the other two groups were given the same boluses as well as a continuous i.v. infusion of either 1 mg.kg-1 of morphine (group 2) or 2 mg.kg-1 (group 3). Pain was assessed with a visual analog scale before starting analgesia, and after 1, 2, 3, 4, 8, 16, 24 and 36 h. Total and bolus morphine doses were recorded at the same time. Breathing rate and the level of sedation were measured every hour and blood gases every time 40 mg of morphine had been consumed. Morphine administration was stopped if breathing rate decreased to less than 10 c.min-1, the patient became too sedated, or PaCO2 rose to more than 45 mmHg. Pain scores were similar in the three groups. Total amounts of morphine were higher in groups 2 (56.8 +/- 23.8 mg) and 3 (116.2 +/- 41.8 mg) compared with group 1 (38.2 +/- 17.8 mg) (p < 0.05). Morphine administration was stopped in 5 patients in group 3 and in 1 in group 2 because PaCO2 had risen to more than 45 mmHg. Therefore, a continuous i.v. infusion is not required in patients receiving PCA, all the more so as this has deleterious respiratory effects.
Aged↗
A dose-range study of intrathecal meperidine combined with bupivacaine.
Twenty-one patients were included in a randomized study to receive either 10 mg of 0.5% hyperbaric bupivacaine alone or combined with 0.05, 0.1, 0.2, 0.3, 0.4 or 0.5 mg.kg-1 meperidine for spinal anaesthesia. Sensory blockade was assessed by pin prick, motor blockade by the Bromage scale, and postoperative analgesia by VAS scores and by the time before the first demand for analgesia. Spinal meperidine did not change the duration of sensory blockade, but induced a dose-related increase in postoperative efficient analgesia. Spinal meperidine might be considered as a means to obtain postoperative analgesia in the hours immediately following surgery.
Aged↗
Effect of thoracic epidural anesthesia combined with general anesthesia on segmental wall motion assessed by transesophageal echocardiography.
Patients scheduled for vascular surgery are considered at risk for perioperative cardiac complications. Choice of anesthetic in such patients is guided by a desire not to adversely affect myocardial function. On the basis of data from laboratory studies, thoracic epidural anesthesia (TEA) has been advocated to prevent myocardial ischemia. The aim of this study was to assess whether TEA combined with general anesthesia has any effect on segmental wall motion (SWM) monitored by transesophageal echocardiography in these patients. Patients received alfentanil, midazolam, vecuronium, and 50% N2O in oxygen, and ventilation was controlled after orotracheal intubation; 12.5 mL of 2% lidocaine HCl was injected through an epidural catheter placed at T6-7 or T7-8. Hemodynamic measurements and transesophageal echocardiographic recordings were obtained before and 10, 20, 30, 40, and 60 min after lidocaine injection. Segmental wall motion was graded a posteriori by two independent experts on a predetermined scale (from 1 = normal to 5 = dyskinesia). A decrease greater than or equal to 2 grades was considered an SWM abnormality indicative of ischemia. Thoracic epidural anesthesia induced a decrease in systemic arterial blood pressure, heart rate, and cardiac index. The SWM score decreased slightly from 1.34 +/- 0.68 to 1.27 +/- 0.64 (mean +/- SD) (at 10 and 20 min, respectively) (P less than 0.05). Patients were a posteriori analyzed according to whether they had documented coronary artery disease or not. The SWM score before TEA was significantly higher in patients with documented coronary artery disease (1.51 +/- 0.88 vs 1.17 +/- 0.51, respectively; P less than 0.05) and did not change significantly after TEA.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Effect of preoperative normovolemic hemodilution on left ventricular segmental wall motion during abdominal aortic surgery.
Preoperative normovolemic hemodilution (PNH) has been proposed for patients scheduled to undergo aortic surgery. Coronary artery disease is frequent in these patients. The aim of the study was to assess the effect of PNH on hemodynamics and segmental wall motion (SWM) evaluated by transesophageal echocardiography in such patients. Twenty patients with coronary artery disease were allocated randomly to either PNH or no PNH; PNH was performed after anesthetic induction using dextran 60,000. Patients were operated on under general anesthesia and monitored intraoperatively with electrocardiographic lead CM5, radial and pulmonary artery catheters, and transesophageal echocardiography positioned to obtain a short-axis view. Hemodynamic and transesophageal echocardiographic data were collected after anesthetic induction and after PNH, before and 5 min after aortic clamping, after unclamping, and at the end of surgery. Aortic clamping induced a significant increase in systemic vascular resistance and arteriovenous difference in oxygen and a decrease in cardiac index (P < 0.05), but the effect of aortic clamping was inversely related to hemodilution. The SWM score (graded from 1 = normal to 5 = dyskinesia) was significantly increased after aortic clamping, mainly in the anterior segment (P < 0.05). Four patients in the control (no PNH) group and one in the PNH group developed new SWM abnormalities indicative of myocardial ischemia during surgery (P = NS). This study suggests that PNH may improve hemodynamic tolerance to aortic clamping in patients with coronary artery disease. The observed changes in SWM indicate that PNH may not worsen myocardial ischemia in patients scheduled to undergo aortic surgery.
Aged↗
[Place of locoregional spinal anesthesia: indications and possibilities].
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Anesthesia, Epidural↗
[The principles of managing postoperative pain].
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Analgesia, Patient-Controlled↗
Pharmacokinetics of midazolam in children: comparative study of intranasal and intravenous administration.
Twelve children 1-5 y old were randomly assigned to receive midazolam 0.2 mg.kg-1 either by the intravenous (IV) or intranasal (IN) routes. After IN administration the rapid onset of absorption was observed (tmax 12 min). After both routes of administration the half-life was similar (2.2 h IN and 2.4 h IV). After IN administration the apparent plasma clearance and volume of distribution were about twice as high as after IV administration. The results are consistent with an estimated mean bioavailability of 55%.
Administration, Intranasal↗
[Analysis of failures of spinal anesthesia as a function of practice development in a university hospital].
This study is a retrospective analysis of 303 consecutive spinal anaesthesia performed in orthopaedic patients of a University Hospital between January and December 1990. Failure of spinal anaesthesia was defined as the requirement for general anaesthesia to perform surgery. The parameters studied as possible risk factors of failure were patients demographics, local anaesthetic agents and solutions and techniques of spinal anaesthesia (single injection versus continuous spinal anaesthesia). Failures were related to inadequate or incomplete extension of sensory blockade or to difficulties to perform spinal injection. Continuous spinal anaesthesia was performed in 209 patients mostly with 0.5% isobaric bupivacaine, while 94 patients received a single injection of either hyperbaric 0.5% tetracaine with adrenaline or 0.5% bupivacaine or 5% lidocaine. Failures occurred in 6.3% of the cases but were significantly less frequent with continuous spinal anaesthesia (4.8%) than with the conventional technique (9.6%). The incidence of failure was higher with hyperbaric tetracaine (11.1%) confirming its poor reliability. Inadequate extension of the anaesthetic block was the main cause of failure whatever the spinal anaesthetic technique. These results point out the reliability of continuous spinal anaesthesia but problems may occasionally occur due to spinal catheter misplacement.
Academic Medical Centers↗
Clonidine decreases postoperative oxygen consumption in patients recovering from general anaesthesia.
Twenty ASA I patients, undergoing thyroid surgery were allocated randomly to receive at the end of surgery either an isotonic saline solution or clonidine 2 micrograms kg-1 i.v. administered over 20 min. Oxygen consumption (VO2) and carbon dioxide production (VCO2) were measured during recovery in patients breathing spontaneously with a head canopy system. Clonidine was found to attenuate the increase in VO2 and VCO2 associated with recovery from anaesthesia. The effect of clonidine was associated with a reduction in shivering. Sedative and analgesic properties of clonidine may also contribute to the reduction in metabolic demand during recovery from anaesthesia.
Adult↗
[Pharmacology and mechanism of action of opiates administered by the subarachnoid route].
The sites of action of spinally administered opiates are specific receptors (mu kappa delta) located in the spinal dorsal horn. Pharmacokinetics of spinally administered opiates are determined by their lipophilic property. Morphine has a weak octanol-water partition coefficient and remains in the CSF during a long period following the cephalic movements of lumbar CSF to the supraspinal structures. More lipophilic opiates are rapidly eliminated from the CSF. Nevertheless, significant pethidine concentrations are documented in the ventricular CSF, due to vascular absorption of the drug. Pharmacokinetics features of different opiates determine the duration of analgesia and the risk of respiratory depression after spinal injection.
Analgesics, Opioid↗
[Serum immune complexes and cardiopulmonary bypass. A review of thirty-four cases (author's transl)].
The immunologic status of patients undergoing cardiopulmonary bypass as investigated. Rheumatoid factor, cryoglobulinemia and serum immune complexes were looked for. Studies were performed before the operation and eight or fifteen days later. From the results, it is concluded that the immunologic changes that occur in the immediate postoperative period cannot be interpreted because of the profound modifications resulting from cardiopulmonary bypass.
Antigen-Antibody Complex↗
Blocks at the wrist provide effective anesthesia for carpal tunnel release.
PURPOSE: Distal blocks are not recommended even for a short procedure when a tourniquet is used. This study was designed to evaluate the tolerance, effectiveness, patient acceptance and safety of distal blocks at the wrist. METHODS: Consecutive patients (n=273, mean age 53 +/-15 yr) undergoing endoscopic carpal tunnel release with a pneumatic tourniquet were included in this study. The median nerve was blocked 6 cm above the wrist crease by injecting 10 mL of 2% lidocaine and 0.5% bupivacaine (v/v). The ulnar nerve was blocked by injecting 8 mL of the same anesthetic mixture below the flexor carpi ulnaris tendon 6 cm above the wrist crease. Finally, 2 mL of local anesthetic were infiltrated sc and laterally below the crease to block the musculocutaneous nerve. The intensity of the block was evaluated after five, ten and 20 min. In addition, pain associated with block performance and tolerance of the tourniquet were evaluated. Finally, neurological complications associated with this technique were investigated. Data are presented as means +/- SD. RESULTS: At ten minutes after the block was performed, 9% and 32% of patients required an additional injection to complete the block in the median and ulnar territories, respectively. In more than 75% of patients, performance of the block was associated with either no or mild pain. The tourniquet was inflated for 12.6 +/- 5.4 min and was well tolerated in 99% of patients. Finally, neither transient nor permanent neurological deficit were recorded postoperatively. CONCLUSION: Blocks at the wrist are effective, well accepted by the patient and safe when a pneumatic tourniquet is used for a short procedure.
Aged↗
Epidural clonidine decreases postoperative requirements for epidural fentanyl.
OBJECTIVE: This study assesses the possibility that clonidine may decrease analgesic opioid demand in postoperative patients. METHODS: Twenty-five patients were allocated randomly after abdominal surgery to receive either an epidural bolus dose of fentanyl (1.0 mcg.kg-1) followed by a 1.0 mcg.kg-1h-1 continuous epidural infusion, or an epidural bolus dose of fentanyl (1.0 mcg.kg-1) followed by a continuous epidural infusion combining fentanyl 0.5 mcg.kg-1 x h-1 and clonidine 0.3 mcg.kg-1 x h-1. Pain was assessed at definite intervals on a visual analog scale (VAS) over 3 postoperative days. Epidural infusion was halved when VAS score was lower than 2. Patients were monitored with a pulse oximeter over 12 hours during the first postoperative night. Plasma fentanyl was measured by radioimmunoassay when patients left the recovery room and at 8 a.m. on the first and the second postoperative days. RESULTS: VAS scores were comparable in the two groups of patients. The amount of fentanyl delivered was significantly lower in the fentanyl + clonidine group, as were the plasma fentanyl concentrations. The duration of SaO2 < 90% episodes was significantly less prolonged in the fentanyl + clonidine group (3.5 +/- 4.8 minutes versus 14.4 +/- 14.6 minutes). CONCLUSIONS: The combination of clonidine to epidural fentanyl allows a decrease in opioid requirements without impairing analgesia. Reduction of opioids administration may have beneficial effects on respiratory function in postoperative patients.
Abdomen↗