Extradural Blockade Research Articles

Bayesian enhanced meta‐analysis of post‐operative analgesic efficacy of additives for caudal analgesia in children

The authors calculated the effect size for post-operative analgesia of three additives, clonidine, neostigmine, and tramadol to bupivacaine, ropivacaine, or levobupivacaine used for single-dose caudal extradural blockade in children. A meta-analysis was performed for three end points of efficacy: the increase of time until administration of analgesic drugs, the proportion of patients requiring analgesic drugs during the initial 24 post-operative hours, and the amounts of post-operative analgesic drugs. A Bayesian inference supporting direct statements about the probability of the magnitude of an effect was used to compare the effects size. Neostigmine increased the duration of analgesia by 9.96 h (95% confidence interval: 7.75 to 12.16), as compared with 3.68 h (2.65 to 4.7) with clonidine and 4.45 (2.84 to 6.07) with tramadol. There is a 95% probability that neostigmine increases the duration of post-operative analgesia by more than 8 h, clonidine by more than 2.8 h, and tramadol by more than 3.25 h, as compared with local anesthetics alone. The odds ratios for the proportion of patients requiring analgesic drugs were 0.22 [0.13 to 0.37] for clonidine and 0.28 [0.10 to 0.75] for neostigmine. With tramadol, there was no statistically significant difference. All three additives reduced the amounts of post-operative analgesic drugs. Neostigmine and tramadol increase the probability for post-operative nausea or vomiting (PONV). Neostigmine provides the longest post-operative analgesia. With clonidine, the duration of analgesia is shorter and sedation is increased, but the probability for PONV could be decreased.

Effect of Low Dose Propranonol on Perioperative Stress Induced Hemodynamic Changes in Upper Abdominal Surgery

Stress response is accompanied by an increased traffic in sympathetic efferent tracts resulting in potentially severe hypertension, tachycardia and is associated with post-operative morbidity. Study establishes the assumption that ‘stress free' general anesthesia is necessarily advantageous. A recent study has suggested that different pre-medication may lead to an alteration in sympatho-adrenal stress response during surgery. Several agents and regimens have been devised to control this stress induced haemodynamic responses including alphablocker droperidol, lignocaine, low dose opioid and cervical extradural blockade. It has been demonstrated that beta-adrenoceptor blocker, in therapeutic doses, caused only modest reduction in cardiac output while decreasing the incidence of arrhythmia and myocardial ischaemia after laryngoscopy and intubation. It is recommended that their administration to be continued until the day of surgery. Even a single dose of a beta-blocker given as a premedication decreases the incidence of episodes of myocardial ischaemia. Atenolol, a selective beta-blocker, per oral significantly reduces cardiovascular morbidity in non-cardiac surgery. Propranolol, a non-selective beta-blocker, has an added advantage of alleviating effect in anxiety. In addition, cost of propranolol is generally low and the systems required to use them according to the protocol used in this study are already in place. This prospective study was performed to establish its effects on per-operative haemodynamic response in non-cardiac surgery. The effect of propranolol on heart rate, systolic arterial pressure and derived value rate pressure product (RPP) on peri-operative period was significantly different from that of placebo effect. The result showed that propranolol significantly reduces heart rate, SAP & thus RPP & reduces peri-operative morbidity and mortality. Journal of BSA, Vol. 19, No. 1 & 2, 2006 p.14-19

A survey of pediatric caudal extradural anesthesia practice

Caudal extradural blockade is one of the most commonly performed procedures in pediatric anesthesia. However, there is little information available on variations in clinical practice. To perform a survey of members of the Association of Paediatric Anaesthetists of Great Britain and Ireland who undertake caudal anesthesia. An 'online' World Wide Web questionnaire collected information on various aspects of clinical practice. The survey ran from April to June 2008. There were 366 questionnaires completed. The majority of respondents had >5 years of pediatric experience and performed up to ten caudal extradural procedures a month. The commonest device used was a cannula (69.7%) with 68.6% using a 22G device. There was a trend toward the use of a cannula in those anesthetists with <15 years experience, while those with >15 years experience tended to use a needle. Most anesthetists (91.5%) did not believe that there was a significant risk of implantation of dermoid tissue into the caudal extradural space. The majority used a combination of clinical methods to confirm correct placement. Only 27 respondents used ultrasound. The most popular local anesthetics were bupivacaine (43.4%) and levobupivacaine (41.7%). The most common additives were clonidine (42.3%) and ketamine (37.5%). The caudal catheter technique was used by 43.6%. Most anesthetists (74%) wear gloves for a single shot caudal injection. This survey provides a snapshot of current practice and acts a useful reference for the development of enhanced techniques and new equipment in the future.

One hundred and fifty hepatic resections: evolution of technique towards bloodless surgery.

A technique of hepatic resection is described and the results of 150 resections are reviewed. Hepatic transection was performed, under intermittent portal inflow occlusion, using ultrasonic aspiration to skeletonize portal branches and venous tributaries. Control of venous haemorrhage during resection was optimized by argon beam coagulation and lowering central venous pressure to between 0 and 4 cmH2O by extradural blockade and systemic nitroglycerine infusion. One patient with jaundice died in hospital, giving a mortality rate of 0.7 per cent. There were no deaths in patients without jaundice and cirrhosis. Fifteen patients (10.0 per cent) had significant complications, nine medical and six surgical, including three bile leaks (2.0 per cent). Mean blood loss was 814 ml for the whole study but only 434 ml in the last 4 years. During this latter period mean blood transfusion in hospital was 0.5 units and mean postoperative haemoglobin value fell by 0.7 g per 100 ml. Hepatic resection can be performed with the same degree of confidence and similar low morbidity as any other major surgical procedure.

Changes in Plasma Metallothionein-1, Interleukin-6, and C-Reactive Protein in Patients After Elective Surgery

Surgical trauma is a stimulus for the acute-phase response (APR), which is thought to be mediated by cytokines such as interleukin-6 (IL-6) (1). Features of the APR include changes in plasma concentrations of proteins such as C-reactive protein (CRP) and albumin and a lowering of plasma Zn and Fe concentrations (2). The metallothioneins (MTs), a family of metal-binding proteins, are also likely to be increased during the APR. Indeed, MT-1 and MT-2 genes are responsive to a wide variety of stimuli, including metals, cytokines, glucocorticoid hormones, and stress (3)(4). We previously reported a sevenfold increase in circulating MT-1 concentrations 24–48 h after elective surgery (5), confirming observations in animal experiments that MT can act as an acute-phase reactant (6)(7). We also previously showed (8) that extradural anesthesia added to general anesthesia resulted in lower concentrations of cortisol and growth hormone than did general anesthesia alone, but IL-6, CRP, and Zn concentrations did not change significantly. Here, we have investigated the time course of the changes in plasma concentrations of MT-1, CRP, and IL-6 in patients undergoing elective surgery. We also studied the effects of extradural blockade in addition to general anesthesia. Because MT is induced …

Aspirin is contraindicated in extradural blockade

Aspirin is contraindicated in extradural blockade

Safety and Efficacy of a Low Volume Extradural Test Dose of Bupivacaine in Labour

In order to test the safety and effectiveness of a 1.6 ml test dose of 0.5% bupivacaine to determine if intrathecal injection has taken place during extradural blockade, 2 groups of women who required anesthesia for labor and delivery were studied. Group I (20) comprised individuals scheduled for elective cesarean section who received an intrathecal injection of 1.6 ml of 0.5% bupivacaine, followed by introduction of a standard epidural space catheter. Group II patients received an epidural catheter and had 1.6 ml of 0.5% bupivacaine injected via the catheter. In all patients progressive determination was made of spread of response to pinprick, extent of motor blockade and the incidence of hypotension.

Management of pain in advanced intrapelvic malignant disease by caudal extradural neurolytic blockade

Management of pain in advanced intrapelvic malignant disease by caudal extradural neurolytic blockade

Complications of Spinal Anaesthesia Following Extradural Block for Caesarean Section

After extradural blockade failed to extend sufficiently for elective Caesarean section, spinal anaesthesia was performed using 1.6 ml of hyperbaric 0.5% bupivacaine solution in 8% glucose (Marcain Heavy). The patient rapidly developed sensory blockade to the level of T2, and became distressed and dyspnoeic. General anaesthesia was induced. Despite i.v. ephedrine and fluid loading, severe hypotension occurred, which responded subsequently to further doses of ephedrine and infusion of colloid. A healthy infant was delivered by Caesarean section.

Extradural Block With Bupivacaine

In a randomized, double-blind study the influences of the characteristics of both solution (dose, volume, concentration) and patient (age, weight, height, body mass index) on the development of extradural blockade produced by a low lumbar injection of bupivacaine were investigated. Thirty patients aged between 20 and 50 yr received one of three solutions (groups I-III, respectively): 0.75% 10ml (75 mg); 0.5% 15ml (75mg); 0.75% 15ml (112.5mg). A further 20 patients older than 50 yr received 0.75% bupivacaine 10ml (group IV, n=10) or 15 ml (group IV, n=10). The number of segments blocked at maximal extent of block was virtually the same in each group: group I (0.75 % 10ml) 13.3 (SD 1.4); group II (0.5 % 15 ml) 14.1 (2.9); group III (0.75% 15 ml) 13.8 (2.2); group IV (0.75 % 10 ml) 14.2 (2.1); group V (0.75% 15 ml) 16.7 (3.1). The larger dose of bupivacaine (112.5 mg) produced the fastest onset and longest duration of block. Onset and recovery intervals were similar with 0.75% and 0.5% solutions when administered at the same dose (75 mg in 10 ml or 15 ml). There was no correlation between the level of block and the age, weight and height of the patient In patients who received 15-ml injections, there was a positive association between the upper level of block and body mass index.

PULSE OXIMETRY DURING EXTRADURAL ANALGESIA FOR EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY

Exracorporeal shock wave lithotripsy (ESWL) may require immersion of the patient in water and extradural blockade for analgesia, which may both affect pulmonary and cardiovascular function and increase the likelihood of hypoxaemia. Twenty-four patients (ASA I-III) with extradural blockade and six healthy subjects were studied by pulse oximetry during immersion. Oxygen saturation (SaO2) tended to decrease after induction of extradural analgesia. Immersion decreased SaO2 further, by up to 2% in healthy volunteers (P less than 0.05) and 3% in patients (P less than 0.05). In two patients with arteriosclerosis, an SaO2 of 92% was accompanied by arrhythmias which resolved after administration of oxygen.

Failure of Extradural Blockade in Obstetrics. A New Hypothesis

The incidence of unsatisfactory extradural blockade during labor varies from 1.5% to 21% with unilateral blockade the most common complaint. Explanations for this problem have included midline septa, fibrous adhesions, dural folds, and separate anterior/posterior extradural spaces. The authors consider that the commonest cause is incorrect, lateral placement of the catheter by the operator.

EXTRADURAL BLOCK WITH BUPIVACAINE: INFLUENCE OF DOSE, VOLUME, CONCENTRATION AND PATIENT CHARACTERISTICS

In a randomized, double-blind study the influences of the characteristics of both solution (dose, volume, concentration) and patient (age, weight, height, body mass index) on the development of extradural blockade produced by a low lumbar injection of bupivacaine were investigated. Thirty patients aged between 20 and 50 yr received one of three solutions (groups I-III, respectively): 0.75% 10 ml (75 mg); 0.5% 15 ml (75 mg); 0.75% 15 ml (112.5 mg). A further 20 patients older than 50 yr received 0.75% bupivacaine 10 ml (group IV, n = 10) or 15 ml (group V, n = 10). The number of segments blocked at maximal extent of block was virtually the same in each group: group I (0.75% 10 ml) 13.3 (SD 1.4); group II (0.5% 15 ml) 14.1 (2.9); group III (0.75% 15 ml) 13.8 (2.2); group IV (0.75% 10 ml) 14.2 (2.1); group V (0.75% 15 ml) 16.7 (3.1). The larger dose of bupivacaine (112.5 mg) produced the fastest onset and longest duration of block. Onset and recovery intervals were similar with 0.75% and 0.5% solutions when administered at the same dose (75 mg in 10 ml or 15 ml). There was no correlation between the level of block and the age, weight and height of the patient. In patients who received 15-ml injections, there was a positive association between the upper level of block and body mass index.

EFFECTS OF POSTURE AND BARICITY ON SPINAL ANAESTHESIA WITH 0.5% BUPIVACAINE 5 ML: A Double-Blind Study

In four groups of 10 patients, 0.5% bupivacaine 5 ml was used in spinal anaesthesia for gynaecological surgery. Group 1 received plain solution in the sitting position, group 2 plain solution in the lateral position, group 3 hyperbaric solution in the sitting position and group 4 hyperbaric solution in the lateral position. All patients were returned to the horizontal supine position, the sitting subjects 2 min after, and the lateral subjects immediately after, spinal injection. In each group the mean height of block was to the mid-thoracic segments, but there was no significant difference between the groups. There was, however, considerable scatter within each group. Posture had some effect on the speed of onset of the analgesia, but no significant effect on the final outcome. The use of 0.5% bupivacaine as a test dose in extradural blockade is discussed.

EFFECT OF EXTRADURAL BUPIVACAINE OR I.V. DIAMORPHINE ON CALF BLOOD FLOW IN PATIENTS AFTER SURGERY

Strain gauge venous occlusion plethysmography was used to measure arterial flow, venous capacity and maximum venous outflow in the calves of seven patients undergoing gynaecological surgery. Plethysmography was performed before surgery, before, and for 30 min after, the extradural injection of 0.5% bupivacaine. On the morning after surgery, 0.5% bupivacaine was injected extradurally and plethysmography performed. With regression of the extradural blockade and the re-emergence of pain, analgesia was produced with diamorphine i.v. and plethysmography repeated. Control measurements were also made. Compared with a mean control value of 100% (3.4 ml dl-1 min-1) calf arterial flow increased from 160% to 285% after the preoperative extradural blockade, and from 123% to 191% following the postoperative analgesic extradural blockade, but there was no significant change when pain was relieved after i.v. diamorphine. Mean arterial pressure changed insignificantly after all the injections. No significant changes were measured in venous capacity or maximum venous outflow.

Delayed vomiting after papavaretum in paediatric outpatient surgery.

The contribution of papavaretum to the incidence of vomiting observed in the 24 hours after paediatric outpatient anaesthesia was assessed in 129 children undergoing circumcision. Postoperative analgesia in all patients was achieved using caudal extradural blockade. The incidence of vomiting in the 24 hours after discharge from hospital was 56 per cent in those receiving papavaretum, compared with 15 per cent in those who did not (p less than 0.0001). The significance of this finding and the use of opiates in paediatric outpatient anaesthesia are discussed.

INFLUENCE OF EXTRADURAL BLOCKADE AND EPHEDRINE ON TRANSCUTANEOUS OXYGEN TENSION

The influence of lumbar extradural blockade with 0.5% pain bupivacaine on transcutaneous oxygen tension (PtcO2) and skin temperature was studied in 20 patients, 10 scheduled for vascular surgery and 10 for urological surgery. At the time of maximum extent of blockade, mean arterial pressure (MAP) had decreased significantly (P less than 0.001) from 96.6 +/- 18.8 mm Hg to 69.5 +/- 10.1 (mean +/- SD) in the vascular group and from 88.0 +/- 14.7 mm Hg to 71.1 +/- 12 mm Hg in the urological group. In the vascular group PtcO2 decreased significantly in the ischaemic (P less than 0.01) and non-ischaemic (P less than 0.001) limbs. In the urological group, there was a significant (P less than 0.001) decrease in PtcO2 in both limbs. There was no change in cutaneous temperature in the ischaemic limbs (vascular group), but the temperature in the non-ischaemic limbs increased significantly (P less than 0.01). In the urological group, the cutaneous temperature increased significantly (P less than 0.001) in both limbs. When ephedrine 10 mg was administered i.v., MAP increased significantly (P less than 0.001) in both groups to pre-blockade values. This was accompanied in both groups by significant increases in PtcO2' but not by a change in skin temperature. There was a significant correlation between change in MAP and change in PtcO2 in both groups after ephedrine.

EFFECT OF EXTRADURAL ANALGESIA ON GLUCOSE METABOLISM AND GLUCONEOGENESIS: Studies in Association with Upper Abdominal Surgery

Concentrations of glucose and gluconeogenic substrates across the splanchnic circulation were studied in 20 patients undergoing cholecystectomy with general anaesthesia. In 10 patients, general anaesthesia was administered alone, and in 10 general anaesthesia was combined with thoracic extradural analgesia. All patients received a constant i.v. infusion of glucose. Blood glucose concentration increased markedly in the general anaesthesia group in contrast to a moderate and shortlived increase in the patients given extradural analgesia, in whom the splanchnic release of glucose tended to be lower. The splanchnic uptake of glycerol was lower in the patients given extradural analgesia, while the uptake of lactate and the increase in alanine uptake was similar in both groups. Plasma catecholamine and serum cortisol concentrations were higher in the group receiving general anaesthesia alone, while serum growth hormone concentration was higher after surgery in the extradural group. The addition of extradural blockade to general anaesthesia suppresses the increase in blood glucose concentration--and this may be related to a reduced splanchnic release of glucose combined with an increased peripheral uptake.

EFFECTS OF COMBINED EXTRADURAL BLOCKADE AND GENERAL ANAESTHESIA ON INDOCYANINE GREEN CLEARANCE AND HALOTHANE METABOLISM

Cardiovascular effects, indocyanine green clearance and the reductive metabolism of halothane were compared in 10 patients having peripheral surgery who received either general anaesthesia or general anaesthesia plus extradural blockade. Bupivacaine or saline was given extradurally 1 h before anaesthesia with nitrous oxide:oxygen (70:30) and halothane (end-tidal concentration 0.35%). Indocyanine green clearance was measured before (stage I) and after (stage II) bupivacaine or saline, during anaesthesia before surgery (stage III), and during surgery (stage IV). Reductive metabolism of halothane was assessed by measurement of exhaled 2-chloro-1,1,1-trifluoroethane. In the general anaesthesia plus extradural blockade group, arterial pressure was decreased to 58% (SD = 6) of stage I values over stages II-IV, whereas no changes were observed in the general anaesthesia group. There was no significant difference in indocyanine green clearance or the reductive metabolism of halothane, despite the occurrence of significant decreases in arterial pressure.

COMPARISON OF THE EFFICAY OF CHLORMETHIAZOLE AND DIAZEPAM AS I.V.SEDATIVES FOR SUPPLEMENTATION OF EXTRADURAL ANAESTHESIA

The clinical efficacy of two sedative agents was compared in 21 young healthy patients undergoing surgery under extradural blockade. A state of sedation and amnesia in which patients lapsed into a sleep-like state when left undisturbed, yet spontaneously opened their eyes to make comments and co-operate with verbal commands, was sought. This was achieved readily by careful titration of responses and required a diazepam loading dose of 20 (+/- 15) mg given at a rate of 1 mg min-1 or 0.8% chlormethiazole edisylate infusion 10 ml min-1 given over 16 (+/- 6) min. Control of this state was easier with chlormethiazole (by varying the rate of infusion) than by giving repeated doses of diazepam. Both agents provided good anterograde amnesia; there was no retrograde amnesia. Considerable postoperative somnolence with a high incidence of relapse into amnesic and sedated states were noted with both agents. However, if the total volume of chlormethiazole infused was less than 300 ml, then a distinct advantage of abrupt and lucid recovery was apparent. Blood concentrations producing the desired clinical state were more variable for diazepam than for chlormethiazole.