Understanding spinal anaesthesia.
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Anesthesia, Spinal↗
Biomedical subjects
J L Scholtes
Publications and source records attributed to J L Scholtes.
Intravenous administration of tenoxicam 40 mg for post-operative analgesia: a double-blind, placebo-controlled multicentre study.
The analgesic efficacy of tenoxicam, a newer injectable non-steroidal anti-inflammatory drug, for post-operative analgesia after abdominal or orthopaedic surgery in ASA Grade I/II patients is reported. Two hundred and fifty-six patients received a single dose of tenoxicam 40 mg intravenous (i.v.) at the end of surgery and this was repeated 24 h later. These patients were compared, with respect to pain or adverse events, with 258 patients that received placebo. All patients were monitored for the next 72 h. Overall, tenoxicam provided reliable analgesia with comparable pain scores at rest, moving and coughing. The cumulative rescue PCA-morphine consumption was always lower in the tenoxicam treated patients and was most marked at 4 and 24 h after the second injection of tenoxicam. This effect was more pronounced after abdominal surgery. The intravenous administration of tenoxicam was associated with a low incidence of adverse events and a high tolerability.
Abdomen↗
Analgesic doses of intrathecal but not intravenous clonidine increase acetylcholine in cerebrospinal fluid in humans.
Epidural clonidine increases acetylcholine (ACh) concentrations in cerebrospinal fluid (CSF) in humans, and experiments in animals support a cholinergic link in spinal alpha2-adrenoceptor-mediated antinociception. The purpose of the present study was to evaluate whether intravenous (I.V.) clonidine is also able to increase CSF ACh in humans. Accordingly, we studied 20 patients scheduled for resection of an acoustic neuroma under general anesthesia. Anesthesia was induced with propofol and maintained with propofol and N2O. After induction, an intrathecal catheter was inserted at the L3-4 interspace. Patients were then assigned, in a random, blind manner to receive either a bolus of 1 microg/kg intrathecal (I.T.) clonidine and an I.V. infusion of saline (n = 10) or an I.V. infusion of 4 microg/kg clonidine given in 20 min and an I.T. injection of saline (n = 10). CSF samples for ACh and clonidine concentration determination were drawn immediately before I.T. injection (time -20), at the end of the I.V. injection (time 0), then every 10 min thereafter. CSF ACh concentrations were determined by high-pressure liquid chromatography and CSF clonidine by radioimmunoassay. There was no significant difference between the groups with respect to age, gender, weight, and ASA physical status. I.T. but not I.V. administration of clonidine increased the CSF ACh concentration. We conclude that I.V. administration of four times the dose of clonidine delivered spinally failed to induce a significant increase of ACh in the CSF. These observations indicate that the analgesic effects observed after I.V. clonidine administration are not mediated by a cholinergic mechanism at the spinal level.
Acetylcholine↗
Epidural clonidine used as the sole analgesic agent during and after abdominal surgery. A dose-response study.
BACKGROUND: Many studies have shown the beneficial effect of epidural clonidine in postoperative pain management. In these studies, the patients received local anesthetics, opioids, or both in combination with clonidine. Due to the interactive potentiation of those drugs, the importance of the intrinsic analgesic properties of the alpha 2-adrenoceptor agonist is difficult to establish. The authors investigated the analgesic potency of epidural clonidine when used as the sole analgesic agent during and after major abdominal surgery. METHODS: Fifty young adult patients undergoing intestinal surgery under general anesthesia with propofol were studied. At induction, the patients received epidurally either an initial dose of 2 micrograms/kg clonidine followed by an infusion of 0.5 microgram.kg-1.h-1 (group 1, n = 10) or 4 micrograms/kg followed by 1 microgram.kg-1.h-1 (group 2, n = 20) or 8 micrograms.kg-1.h-1 followed by an infusion of 2 micrograms.kg-1.h-1 (group 3, n = 20). During the operation, increases in arterial blood pressure or heart rate that did not respond to a propofol bolus (0.5 mg/kg) were treated with a bolus of intravenous lidocaine (1 mg/kg). Three successive injections were allowed. When baseline values were not restored, opioids were added and the patient was removed from the study. After operation, the clonidine infusions were maintained for 12 h. During this period and at every 30 min, sedation scores and visual analog scale values at rest and at cough were noted. In case of subjective scores up to 5 cm at rest or up to 8 cm at cough, the patients were given access to a patient-controlled analgesia device that delivered epidural bupivacaine. The end point of the study was reached once the patient activated the analgesic delivery button. RESULTS: During surgery, 60% of patients in group 1 compared with 33% of patients in group 2 and only 5% of patients in group 3 were removed from the study protocol because of inadequate anesthesia (P < 0.05). After operation, epidural clonidine provided complete analgesia lasting 30 +/- 21 min in group 1 compared with 251 +/- 237 min in group 2 or 369 +/- 256 min in group 3 (P < 0.05 for group 1 vs. groups 2 and 3 and group 2 vs. group 3). CONCLUSIONS: Epidural clonidine used as the sole analgesic agent provided dose-dependent control of the hemodynamic changes associated with surgical stimulation. It also produced dose-dependent postoperative analgesia without major side effects.
Adult↗
Epidemiology of the adverse hemodynamic events occurring during "clonidine anesthesia": a prospective open trial of intraoperative intravenous clonidine.
STUDY OBJECTIVE: Determine the hemodynamic consequences of intraoperative clonidine during major abdominal surgery. DESIGN: Prospective open trial. SETTING: Teaching hospital. PATIENTS: 402 consecutive patients scheduled for major abdominal surgery. INTERVENTIONS: 350 consecutive patients received intravenous (IV) clonidine (loading dose of 4 micrograms/kg in 20 minutes at anesthesia induction, followed by a continuous infusion of 2 micrograms/kg/h until the end of surgery). Fifty-two additional patients served as controls. Anesthetic technique consisted of balanced anesthesia (isoflurane, fentanyl, atracurium). ECG, invasive arterial blood pressure (BP), expiratory PCO2 and pulse oximetry were continuously recorded. Hemodynamic events (HEs) were defined as moderate for a 20% reduction of the baseline systolic blood pressure (SBP) or a heart rate (HR) decreasing between 50 beats per minute (bpm) and 40 bpm. A 30% reduction of the baseline SBP or a HR below 40 bpm was considered an important HE. The rate and duration of these events were recorded from induction to recovery. HEs requiring a specific treatment were noted. Central venous pressure, volume of fluid infused, and urinary output were also recorded. MEASUREMENTS AND MAIN RESULTS: 21% of control patients and 31% of clonidine patients had no adverse HEs. A moderate reduction of the baseline BP was the most common episode in both groups. The incidence of the HEs (moderate and important) was similar in both groups but the duration HEs was significantly longer in the clonidine patients (p < 0.05). 40% of the control patients and 13% of the clonidine patients required specific management for their HEs (p < 0.05), the most common of which was hypotension without bradycardia. Neither coexisting pathology nor preoperative medications influenced the incidence of HEs. CONCLUSION: IV clonidine can be used routinely during anesthesia for major abdominal surgery.
Abdomen↗
Epidural clonidine or sufentanil for intraoperative and postoperative analgesia.
This study contrasts the efficacy and side effects of epidural clonidine and sufentanil in the perioperative period. Using a randomized, prospective, double-blind study design, 40 patients undergoing abdominal surgery under propofol/nitrous oxide anesthesia were enrolled. Before anesthesia, an epidural catheter was inserted at the L1-L2 interspace. At induction of anesthesia, the patients received epidurally either clonidine (4 micrograms/kg in 10 mL) infused in 20 min followed by a 2-micrograms.kg-1.h-1 infusion (5 mL/h) during 12 h (Group 1) or sufentanil (0.5 microgram/kg in 10 mL) in 20 min followed by a 0.25-microgram.kg-1.h-1 infusion (5 mL/h) during 12 h (Group 2). Intraoperatively, increases in arterial blood pressure and heart rate not responding to propofol bolus (0.5 mg/kg) were treated with a bolus of intravenous (IV) sufentanil 0.035 microgram/kg. Postoperatively, IV sufentanil boluses (5 micrograms) were given through a patient-controlled analgesia (PCA) device. Postoperative analgesia was assessed by recording the IV PCA sufentanil requirements and the patients' visual analog scale (VAS) at 3, 6, 12, 18, 24, 36, and 48 h. Sedation analog scales and side effects were also recorded. Plasma clonidine and sufentanil concentrations were measured after 20 min and 6, 12, and 24 h. The number of reinjections of propofol (n = 1.6 +/- 1.6 in Group 1 vs 6.5 +/- 4.0 in Group 2) and of IV sufentanil (n = 0.6 +/- 0.8 in Group 1 vs 3.8 +/- 3.7 in Group 2) was significantly reduced (P < 0.001) in the epidural clonidine group. In the early postoperative period, pain scores and rescue analgesic requirements were very low in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Abdomen↗
[Craniostenosis and craniofacial dysmorphia].
The paper gives a brief historical survey of craniostenosis and the first operative approaches. The authors describe a classification of various types of cranio-facio-stenosis and facio-cranio-stenosis and present a detailed study of their experience in this area. Operative results are discussed in function of the selected surgical procedure, the immediate per- and post-operative complications and the short and long term morbidity. The authors present their current attitude for each dysmorphic type. They underline the heavy nature of this long-lasting and bleeding surgical procedure that concerns small children. They have recorded 31 incidents in relation with surgical procedure, 10 complications at short and long term, and 1 death. Such surgery requires an experienced and vigilant team, associating surgeons, anesthetists and intensive-care physicians.
Child, Preschool↗
Ketorolac tromethamine for postoperative analgesia in oral surgery.
Sixty patients were randomly allocated to receive placebo or i.v. ketorolac tromethamine 30 mg during the induction of anaesthesia for dental removal. Pain score (VAS), mouth opening and oedema were evaluated. Pain intensity was assessed by the patient using a visual analog scale 1, 2, 6 and 24 hrs after surgery. Mouth opening and oedema were evaluated at the same times by an observer not implicated in the study. In ketorolac group, pain relief was better at each considered time (VAS: p < 0.001). Oedema was also significantly lesser. There was no difference in mouth opening. No side effect was observed. These data suggest that ketorolac reduces post-oral surgery pain and oedema.
Adolescent↗
Cervical epidural analgesia for a cancer child at home.
A cervical epidural catheter was placed in a 32-month-old girl suffering from painful bone metastases of a relapsing neuroblastoma in the left forearm. This therapeutic approach was chosen because oral morphine had failed to provide analgesia while producing intolerable side effects. The epidural injection of a mixture of morphine and bupivacaine provided complete analgesia with no side effects. This enabled the parents to take care of their child at home until the end, 35 days later.
Analgesia, Epidural↗
The "ozone-friendly" lidocaine spray affects the monitoring of volatile anesthetics.
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Aerosols↗
Intraoperative and postoperative analgesia using intravenous opioid, clonidine and lignocaine.
The postoperative analgesia afforded after colonic surgery by IV opioid, clonidine and lignocaine given intra- and postoperatively was evaluated. In a double-blind randomised trial, 80 male patients scheduled for colonic resection under general anaesthesia received fentanyl 5 micrograms.kg-1 at induction and another 4 micrograms.kg-1 before skin incision (group A) or fentanyl (same dose) plus clonidine 4 micrograms.kg-1 in 20 min + 2 micrograms.kg-1.h-1 (group B, C) or fentanyl plus clonidine (same dosage) plus lignocaine 2 mg.kg-1 before skin incision, repeated before peritoneal incision and retractor placement (group D). In the four groups, intraoperative boluses of fentanyl 2 micrograms.kg-1 were given in response to the painful stimulation of the procedure. Postoperative pain was managed with PCA delivering 2 mg morphine per request in group A, 1.5 mg morphine in group B, 1.5 mg morphine + 15 micrograms clonidine in group C and 1.2 mg morphine + 15 micrograms clonidine + 23 mg lignocaine in group D. Postoperative analgesia was assessed by recording the analgesic demands (met and unmet) and the dose of morphine delivered at 6, 12, 18, 24, 36 hours. Side-effects, pain and sedation analogue scores were also recorded. Analgesic demands and delivered morphine dose were reduced, at any time interval considered, in groups B, C, D, compared with A (P < 0.001). No differences were noted between the group B, C, D. Pain analogue scores were better in groups B, C, D compared with group A (P < 0.001). Sedation and side-effects were not increased in groups B, C, D.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Effects of intravenous clonidine on the secretion of growth hormone in the perioperative period.
Growth hormone (GH) improves the metabolic and immunitary parameters in the postoperative period. Clonidine, a central acting alpha 2-adrenoceptor agonist stimulates GH release and is currently used as a screening test for GH-deficiency. A continuous iv infusion of clonidine may lead to a sustained increase in GH secretion during the perioperative period. With institutional approval and after informed consent, 20 healthy (ASA 1) patients scheduled for functional middle ear surgery under deliberate hypotensive anesthesia were studied. The anesthetic technique consisted of isoflurane, fentanyl and atracurium. Patients were randomly assigned to two groups. In group 1, hemodynamic stabilisation was obtained with a loading dose of clonidine (4 micrograms.kg-1 in 30 min) and maintained with an infusion of 1 microgram.kg-1.h-1. In group 2, a loading dose of labetalol 0.2 mg.kg-1 was followed by an infusion of 0.1 mg.kg-1.h-1. These infusions were stopped 30 min. before the end of the procedure. GH and glucose concentrations were assayed before the induction of anesthesia, after the loading dose and every 30 min. during the procedure and after the recovery during 2 hours. Serum clonidine levels were assayed after the loading dose, 1 and 3 hours later. Somatomedin C (IGF-I) concentration was measured before the induction and in the first postoperative morning along with GH, glucose and clonidine.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Clonidine combined with sufentanil and bupivacaine with adrenaline for obstetric analgesia.
Clonidine produces analgesia via a non-opioid mechanism and it may be used as an interesting adjuvant to local anaesthetics and opioids in obstetric analgesia. To examine the effects of the addition of clonidine to bolus injections of bupivacaine, adrenaline and sufentanil, we enrolled 50 women receiving extradural analgesia for vaginal delivery into a double-blind study. They were allocated randomly to two groups: group A received a 10-ml extradural solution of bupivacaine 12.5 mg combined with adrenaline 25 micrograms and sufentanil 10 micrograms; group B received the same solution with clonidine 30 micrograms. Each patient was allowed two subsequent injections of the chosen solution. Subsequently, if still in the first stage of labour, analgesia was augmented with additional 10-ml injections of bupivacaine 12.5 mg with adrenaline 25 micrograms, without sufentanil or clonidine. The latter solution was used for perineal analgesia in group A; clonidine 30 micrograms was added in group B. During the first and second stages of labour, there was no difference between the two groups in duration of analgesia after the first injection (142 min in group A; 127 min in group B), number of injections (1.8 in group A; 1.9 in group B) and the total bupivacaine requirements (33.9 mg in group A; 34 mg in group B). The quality of analgesia was evaluated as very good in both groups (23/25 in group A; 24/25 in group B). The degree of motor block or the frequency of other side effects were not enhanced by clonidine.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Clonidine pretreatment reduces the systemic toxicity of intravenous bupivacaine in rats.
BACKGROUND: Clonidine prolongs the duration of sensory and motor block induced by bupivacaine, and this association, in constant infusion by the epidural route, is used for postoperative analgesia. After a near-fatal intravenous bolus of bupivacaine in dogs, clonidine improves ventricular electrophysiologic parameters, but probably worsens bupivacaine-induced bradycardia and depression of the myocardial contractility. The current study, using a rodent animal model, evaluated the influence of clonidine pretreatment on the systemic toxic effects of bupivacaine overdose induced by a constant intravenous infusion. METHODS: Twenty Wistar male rats were anesthetized with thiopental, and controlled ventilation was started with an equal mixture of O2 and N2O. Electrocardiogram (ECG), electroencephalogram (EEG), and invasive arterial blood pressure were continuously recorded. Clonidine (5 micrograms/kg) or saline was injected intravenously in a randomized fashion. After 15 min, an intravenous infusion of bupivacaine was started at 2 mg.kg-1 x min-1. The time of occurrence of the bupivacaine-induced toxic events was recorded and the doses were calculated. Ten (five in each group) additional rats, pretreated according to the same protocol, were killed at the time of the first dysrhythmia, for blood sampling and plasma bupivacaine concentration measurement. RESULTS: Clonidine reduced heart rate and arterial blood pressure before bupivacaine infusion (P < 0.05). The threshold doses at the first QRS modification (11.3 +/- 5.6 vs. 2.1 +/- 0.9 mg/kg) and the first dysrhythmia (40.6 +/- 15.3 vs. 8.48 +/- 3.7 mg/kg), the increase in EEG total spectral power (33.3 +/- 21.9 vs. 8.2 +/- 5.1 mg/kg), the 25 and 50% reduction in baseline mean arterial pressure and heart rate, the isoelectric EEG (58.6 +/- 14 vs. 22 +/- 6.6 mg/kg), and the final systole (99 +/- 16 vs. 51.8 +/- 14.5 mg/kg) were significantly greater in the clonidine group than in the saline group (P < 0.01). The time between the first dysrhythmia and 50% reduction of baseline mean arterial blood pressure was not different between the groups. In the additional series, the first dysrhythmia occurred later (10.9 +/- 4.5 vs. 3.2 +/- 1.0 min, P < 0.01) and plasma bupivacaine levels were greater (18.7 +/- 8.0 vs. 7.8 +/- 3.2 micrograms/ml, P < 0.01) in the clonidine group than in the saline group. CONCLUSIONS: In this model, clonidine given prophylactically delays the toxic manifestations of bupivacaine overdose and does not accentuate the subsequent hypotension.
Anesthesia, Epidural↗
Intravenous or epidural clonidine for intra- and postoperative analgesia.
BACKGROUND: Intravenous and epidural clonidine both produce postoperative analgesia. Several experimental reports demonstrate a spinal site of action for the analgesic effects of this alpha 2-adrenoceptor agonist. Therefore, the authors evaluated the clinical analgesic benefits of using clonidine, both intra- and postoperatively, by the epidural or the intravenous route. METHODS: Using a randomized prospective double-blind study design, 40 patients, between 18 and 50 yr of age, undergoing intestinal surgery under general propofol/nitrous oxide anesthesia, were enrolled. Before anesthesia, an epidural catheter was inserted at the L1-L2 interspace. At induction, a clonidine infusion was started at the doses of 4 micrograms/kg in 10 ml during 20 min, followed by 2 micrograms.kg-1 x h-1 (5 ml/h) during 12 h, either by the epidural (group 1) or by the intravenous (group 2) route. Intraoperatively, increased blood pressure and heart rate not responding to additional propofol bolus (0.5 mg/kg) was treated with a bolus of alfentanil (7 micrograms/kg). Postoperatively, morphine boluses (1.5 mg) were given through a PCA device according to the patient's need. Intraoperative analgesia was assessed by the alfentanil requirements. Postoperative analgesia was assessed by recording the morphine requirements, the visual analogue scale (VAS) at rest and after mobilization, and the patients' analgesia scale at 0, 3, 6, 12, 18, 24, and 36 postoperative hours. Sedation analogue scale and side effects were also recorded. Heart rate and blood pressure were particularly detailed during the first 2 h of the clonidine infusion. Plasma clonidine concentrations were measured after 20 min and 6, 12, and 24 h. RESULTS: Epidural clonidine significantly reduced the intraoperative alfentanil requirements (0.93 +/- 1.2 in group 1 vs. 2.4 +/- 1.8 mg in group 2). The postoperative morphine requirements were also reduced during the first 6 h (8.3 +/- 5.8 in group 1 vs. 17.8 +/- 13.4 mg in group 2). The VAS were comparable in both groups, despite the better patients' analgesia score reported in the epidural group during the first 12 h. There was no difference in sedation score at any time interval considered. Epidural and intravenous clonidine reduced heart rate and blood pressure to the same extent. The plasma clonidine concentrations were less in the epidural group only after the loading doses. CONCLUSIONS: Epidural clonidine reduces the intra- and early postoperative analgesic requirements when compared with the same dose given by the intravenous route. The side effects were similar with the two routes of administration.
Adolescent↗
Intraoperative clonidine enhances postoperative morphine patient-controlled analgesia.
In this prospective study, the postoperative analgesic effects of intraoperative iv clonidine were evaluated. Two hundred consecutive patients undergoing major abdominal surgery were randomly assigned to either balanced anaesthesia with iv clonidine (Group 1) or balanced anaesthesia alone (Group 2). A PCA infuser was connected immediately after tracheal extubation. It was programmed to deliver morphine "on demand" iv boluses at doses of 1 mg for patients greater than 65 yr and 1.5 mg for women or 2 mg for men less than 65 yr old. A blinded observer assessed postoperative analgesia by recording the analgesic demands (both met and unmet), patient pain scores, sedation scores, and any side effects during the first 36 hr after surgery. Intraoperative clonidine reduced the number of analgesic demands during the observation period (45 +/- 27 demands in Group 1 vs 81 +/- 60 in Group 2, P = 0.0001). This resulted in a reduction in morphine delivered (55.4 +/- 30.6 mg vs 67.1 +/- 45.1 mg, P less than 0.05), mainly during the first 12 hr (19.7 +/- 11.1 mg vs 27.6 +/- 18.1, mg P less than 0.001) and the unmet demand rate was also reduced at all time intervals (P less than 0.01). Clonidine did not exacerbate sedation or side effects. However, clonidine provided better analgesia in men and in patients less than 65 yr of age. Intraoperative iv clonidine enhances morphine analgesia after abdominal surgery.
Adult↗
Central effects of epidural and intravenous clonidine in patients anesthetized with enflurane/nitrous oxide. An electroencephalographic analysis.
Epidural clonidine produces regional anesthesia as well as sedation and a decrease in anesthetic requirements. To assess these effects, the electroencephalogram (EEG) was recorded after epidural or intravenous (iv) injection of clonidine during enflurane/N2O anesthesia. Eighteen ASA physical status 1 women undergoing vaginal hysterectomy were allocated randomly to receive epidural clonidine (8 micrograms.kg-1 in 4 ml over 2 min) and iv saline (10 ml over 14 min); or epidural saline (4 ml over 2 min) and iv clonidine (8 micrograms.kg-1 in 10 ml over 14 min); or epidural saline (4 ml over 2 min) and iv saline (10 ml over 14 min). The level of anesthesia was kept constant beginning 10 min before and until 44 min after epidural injection. EEG power spectral analysis was performed throughout the study period using a 2-min average of 8-9-s epochs. Clonidine significantly reduced EEG total power only after epidural administration (P less than 0.05). Relative power increased in the delta band in both the epidural and iv clonidine groups (P less than 0.001). The depression of the total EEG power after epidural injection could be explained neither by systemic absorption alone nor by hemodynamic variations. It may represent the contribution of the direct spinal action of this alpha 2-adrenergic agonist to general anesthesia.
Anesthesia, General↗
Postoperative P.C.A. in abdominal surgery. Analysis of 200 consecutive patients.
Patient-Controlled-Analgesia (PCA) is becoming a standard in post-operative analgesia. This prospective study was designed to get more information on the safety and the efficiency of morphine PCA following abdominal surgery. Two hundred patients were enrroled Morphine requirements, number of unsatisfied demands, patients' satisfaction and side effects were recorded for 36 hours postoperatively. The mean morphine requirement was 23.2 mg for the first 12 hours, 22.2 mg for the next 12 hours and 16 mg for the last 12 hours. Female patients required significantly less morphine than male. Interestingly such difference was no more present for patients older than 60 years. The larger the morphine bolus dose, the greater the total amount needed without any better analgesia. A bolus dose of 1 mg seemed to be the best to be recommended. The variability in the number of unsatisfied demands (i.e. demands during the lockout interval) was quite large. The number of unsatisfied demands was not influenced by the size of the bolus dose. The patients' satisfaction was high: 60% enthusiastic, 36% satisfying, 4% negative. There was no difference in satisfaction linked to gender. On the other hand, a history of a previous surgery experience without PCA raised patients' satisfaction score. Side effects were uncommon. It is concluded that morphine PCA is an efficient and safe technique of post-operative analgesia in abdominal surgery.
Abdomen↗