Mathieu Gielen

Coronary artery bypass grafting using two different anesthetic techniques: Part 2: Postoperative outcome

The aim of the present investigation was to study the effects of intraoperative and postoperative epidural pain management during and after coronary artery bypass grafting (CABG) on the recovery time, postoperative pulmonary and cardiac parameters, visual analog scale (VAS) scores, and sedation scores (SS) compared with patients anesthetized with general anesthesia (GA) whose postoperative pain was relieved with intermittent intravenous (IV) administration of nicomorphine. Fifty-four patients were studied postoperatively after uncomplicated CABG. In the thoracic epidural analgesia (TEA) group (n = 27), intraoperative analgesia was based on high TEA in combination with GA. In the GA group (n = 27), IV anesthesia with high-dose sufentanil and midazolam was used. Postoperative pain management in the GA group consisted of intermittent IV administration of nicomorphine, 0.1 mg/kg every 6 hours, whereas for the TEA group continuous high TEA with 0.125% bupivacaine plus sufentanil, 1:1,000,000 (0.05 mL/cm body length/hr) was used. Patients in the TEA group awakened earlier (148 [34] minutes vs 335 [51] minutes), resumed spontaneous respiration earlier (326 [79] minutes vs 982 [52] minutes), and were extubated earlier (463 [79] minutes vs 1140 [58] minutes). VAS score, SS, and postoperative PaO2 were significantly (P less than or equal to 0.01) better in the TEA group. The incidence of tachycardia (15 vs 2 patients) and postoperative myocardial ischemia (12 vs 4 patients) was higher in the GA group. It is concluded that intraoperative and postoperative pain treatment with epidurally administered bupivacaine plus sufentanil improved the recovery time, as well as pulmonary and cardiac outcome after CABG, when compared with IV postoperative pain treatment after intraoperative GA with sufentanil and midazolam.

Coronary Artery Bypass Grafting Using Two Different Anesthetic Techniques: Part I: Hemodynamic Results

Hemodynamic changes were studied during two different anesthetic techniques in 54 patients undergoing coronary artery bypass grafting (CABG). All patients had normal to moderately impaired left ventricular function and were randomly assigned to two groups. In 27 patients, high thoracic epidural analgesia (TEA) with bupivacaine 0.375% plus sufentanil 1:200,000 (ie, 5 micrograms/mL) was used in combination with general anesthesia with midazolam/N2O; in the other 27 patients, general anesthesia (GA) with midazolam and sufentanil was used. After induction of epidural analgesia, heart rate and mean arterial pressure (MAP) decreased. Changes in cardiac index, systemic vascular resistance, and pulmonary capillary wedge pressure were not observed, whereas the stroke volume index increased significantly. After induction of intravenous anesthesia MAP decreased (20%) in both groups. During the pre-bypass period, metaraminol was used in 7 of 27 patients in the GA group and in 5 of 27 patients in the TEA group to treat hypotension. Inotopic drugs were used in 5 patients in the GA group and in none in the TEA group to treat a low CO. Ten GA patients and 4 TEA patients developed hypertension after sternal spread and the GA patients required more nitroprusside. Four GA patients developed electrocardiographic evidence of prebypass ischemia and, therefore, more nitroglycerin was needed for treating myocardial ischemia. More sodium nitroprusside was needed in the GA group during cardiopulmonary bypass (CPB) and the post-bypass period to treat hypertension with a high SVR. In conclusion, hemodynamic stability was more pronounced in the TEA than the GA group before and after CPB.

Coronary artery bypass grafting using two different anesthetic techniques: Part 3: Adrenergic responses.

Twenty patients were studied during and after coronary artery bypass grafting (CABG). The patients were randomly assigned to two groups. In 10 patients, intraoperative general anesthesia (GA) was based on a combination of intravenous (IV) sufentanil and midazolam. In 10 other patients, thoracic epidural analgesia (TEA) with 0.375% bupivacaine plus sufentanil, 1:200,000 (5 micrograms/mL), and intraoperative GA with midazolam/N2O were used. During the prebypass period, lower heart rates (HR), less variability in mean arterial pressure (MAP), and systemic vascular resistance (SVR) was accompanied by less variability in plasma norepinephrine (NE) concentrations in the TEA group. Although no differences were observed between the groups in perfusion pressure and the amount of vasoactive drugs used during the bypass period, variability in SVR was less in the TEA group. This was accompanied by less increase in NE and less variability in epinephrine (E) plasma concentrations. However, cortisol (Co) release was higher during this period in the TEA group. Weaning from bypass was accompanied by higher MAP and SVR in the TEA group at a lower HR, whereas no differences were observed in the E, NE, and Co plasma concentrations between the groups. During the first and second postoperative days, better pain relief and lower E and Co plasma concentrations were found in the TEA group. It can be concluded that better hemodynamic stability during the prebypass and bypass periods was accompanied by less E and NE release during these periods. Co release in the TEA group was higher during the bypass period. Weaning from bypass was characterized by better hemodynamics in the TEA group.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrasound-guided subgluteal sciatic nerve blocks with stimulating catheters in children: a descriptive study.

We describe our clinical experience of combining ultrasound guidance and nerve stimulation for the insertion of subgluteal sciatic catheters in children. Ten children scheduled for lower limb surgery with a combined general anesthetic and a subgluteal sciatic catheter placement for both operative anesthesia and postoperative pain relief were studied. Under ultrasonographic guidance the sciatic catheter was placed using an 17-gauge 50-mm Arrow® continuous peripheral nerve block needle and a 19-gauge stimulating catheter (Stimucath®). The minimal electrical current required for muscle contraction on the stimulating needle and catheter differed widely among patients. Based on the visualization of the spread of local anesthetic during injection through the catheter, a successful prediction for the sciatic block was made in all patients. All catheters were successfully placed and provided excellent postoperative pain relief without complications.

Epidural bupivacaine, sufentanil or the combination for post‐thoracotomy pain

Analgesia with epidural bupivacaine, sufentanil or the combination was studied in 50 patients who had undergone thoracotomy. During operation all patients received an initial dose of bupivacaine 0.5% with adrenaline 5 μg±ml‐1 (5–10 ml) by thoracic epidural catheter. One hour later the patients were divided into three groups: the bupivacaine group (bupivacaine 0.125%), the sufentanil group (50 μg sufentanil in 60 ml normal saline) and the combination group (50 μg sufentanil in 60 ml bupivacaine 0.125%). Analgesia in the three groups was provided by a continuous epidural infusion (5–10 ml±h‐1) for 3 days. The mean dose of bupivacaine was significantly higher (P<0.05) in the bupivacaine group (12.07 mg±h‐1 (s.e.mean 0.97 mg±h‐1)), compared with the combination group (9.82 mg±h‐1 (s.e.mean 0.43 mg±h‐1)). The mean dose of sufentanil in the sufentanil group was similar to the combination group (6.37 μg±h‐1 (s.e.mean 0.23 μg±h‐1) and 6.52 μg±h‐1 (s.e.mean 0.28 μg±h‐1), respectively. The pain scores on the inverse visual analogue scale of most patients in the bupivacaine group were unacceptably low. The sufentanil group had much better pain scores, but on exercise these patients experienced more pain than the combination group. The combination group had, overall, better pain scores. In the combination group, there were better respiratory results.

Optimization of the Dose of Intrathecal Morphine in Total Hip Surgery: A Dose-Finding Study

UNLABELLED We designed this study to determine the optimal intrathecal dose of morphine in total hip surgery. The optimal intrathecal dose was defined as that providing effective analgesia and minimal side effects 24 h after total hip surgery. Patients (n = 143) scheduled for total hip surgery were randomized to four double-blinded groups with a standardized bupivacaine dose but different doses of intrathecal morphine (Group I = 0.025 mg, Group II = 0.05 mg, Group III = 0.1 mg, and Group IV = 0.2 mg). Pain scores, i.v. morphine intake (patient-controlled analgesia), and morphine-related side effects (respiratory depression, postoperative nausea and vomiting, itching, urinary retention) were recorded for 24 h after surgery. Excellent postoperative pain relief was present in all groups. The highest pain scores were found in Group I. The mean use of systemic morphine administered by patient-controlled analgesia infusion pump was 23.7, 17.8, 10.9, and 9.9 mg in Groups I-IV, respectively (P < 0.01 for Groups III and IV versus Group I). We conclude that 0.1 mg of intrathecal morphine is the optimal dose for pain relief after hip surgery with minimal side effects. IMPLICATIONS Earlier studies showed excellent postoperative pain relief after intrathecal morphine. However, the severity of side effects resulted in decreased enthusiasm for this anesthesia technique. In the present study, we show that an intrathecal dose of 0.1 mg of morphine can be used safely in total hip surgery with excellent postoperative pain relief.

Factors Affecting the Distribution of Neural Blockade by Local Anesthetics in Epidural Anesthesia and a Comparison of Lumbar Versus Thoracic Epidural Anesthesia

The spread of sensory blockade after epidural injection of a specific dose of local anesthetic (LA) differs considerably among individuals, and the factors affecting this distribution remain the subject of debate. Based on the results of recent investigations regarding the distribution of epidural neural blockade, specifically for thoracic epidural anesthesia, we noted that the total mass of LA appears to be the most important factor in determining the extent of sensory, sympathetic, and motor neural blockade, whereas the site of epidural needle/catheter placement governs the pattern of distribution of blockade relative to the injection site. Age may be positively correlated with the spread of sensory blockade, and the evidence is somewhat stronger for thoracic than for lumbar epidural anesthesia. Other patient characteristics and technical details, such as patient position, and mode and speed of injection, exert only a small effect on the distribution of sensory blockade, or their effects are equivocal. However, combinations of several patient and technical factors may aid in predicting LA dose requirements. Based on these results, we have also formulated suggested epidural insertion sites that may optimize both analgesia and sympathicolysis for various surgical indications.

3‐in‐1 lumbar plexus block for muscle biopsy in malignant hyperthermia patients. Amide local anaesthetics may be used safely

A 3411–1 lumbar plexus block with the aid of a nerve stimulator was performed in 32 patients and a psoas compartment block was performed in five patients for muscle biopsy of the upper leg for diagnosis of malignant hyperthermia (MH) susceptibility. Twenty‐two patients were found to be MH susceptible by the in vitro contracture test. Twenty patients received 40 ml prilocaine 1.5% with epinephrine 1:200000 and two received 40 ml bupivacaine 0.5% with epinephrine 1:200000 without any untoward reaction. The 3‐in‐1 block provides a high success rate and excellent analgesia for muscle biopsy of the upper leg. Amide local anaesthetics are safe in MH‐susceptible patients.

Extension of sensory blockade after thoracic epidural administration of a test dose of lidocaine at three different levels

To evaluate the relationship between the level of thoracic epidural injection and the extension of sensory blockade, we inserted radiopaque epidural catheters in 87 patients at the high (C7-T2, n = 28), mid (T3-5, n = 29) or low (T7-9, n = 30) thoracic levels. Fifteen minutes after the epidural administration of 60 mg of lidocaine, the mean (+/- SD) sensory block extension varied from 5.4 +/- 3.1 to 7.7 +/- 1.8 segments. The level of epidural puncture was a statistically significant factor in determining the cranial and caudal borders of sensory blockade (P = 0.0001, analysis of variance), but in determining for the total number of segments blocked. The number of blocked dermatomes located cranially of the puncture level increased significantly with descending injection site (P = 0.0001). We acquired chest radiographs in 61 patients to determine epidural catheter tip position. Direction of the epidural catheter tip was not a significant factor in determining the extension or borders of sensory blockade. We conclude that the extension of sensory blockade in thoracic epidural anesthesia is not influenced by the level of epidural puncture or catheter tip direction. There is, however, a more cranial spread of sensory blockade in the low thoracic region compared with the high thoracic region. Implications: After evaluating the extension and pattern of sensory blockade in high, mid, and low thoracic epidural analgesia, the authors suggest that it is safe to use similar dosage regimens in all three regions, and that in high thoracic epidural analgesia, it is important to insert the epidural catheter at the level of the intended cranial border of blockade. (Anesth Analg 1998;86:332-5)

Ultrasound-guided interscalene brachial plexus block in a child with femur fibula ulna syndrome.

Ultrasound‐guided interscalene brachial plexus block is described in a 7‐year‐old child with femur fibula ulna syndrome. It is suggested that ultrasound is a useful tool in situations where nerve stimulation for nerve localization cannot be used.