The selection of the regional anaesthesia in the transurethral resection of the prostate (TURP) operation

BACKGROUND AND OBJECTIVES: The aim of our study was to compare the three different regional anaesthesia methods in patients who underwent transurethral resection of the prostate (TURP) and to determine the ideal anaesthesia method for TURP operation. METHODS: Totally 77 ASA II-III patients were preloaded with 500 ml 0.9% NaCl solution before regional anaesthesia. In group E (n:27) epidural anaesthesia were achieved by applying 75 mg bupivacaine heavy + 50 microg fentanyl in the L3-L4 intervertebral space. In group SP (n:28) 15 mg bupivacaine heavy + 50 microg fentanyl were used for spinal anaesthesia (L3-L4 intervertebral space) while in group SA (n:30) 10 mg bupivacaine heavy + 50 microg fentanyl were used with saddle blockade. Systolic arterial pressure (SAP), heart rate (HR), peripheral oxygen saturation (SpO2), serum sodium measurement was recorded before and after hydration and during operation. The motor block and sensory level have been measured. RESULTS: Intraoperative SAP values were more stable than the other groups in group SA. The decrease in HR values were significant 15 minutes after prehydration in three groups (p < 0.05). SpO2 values of the groups were stable during the operation. The time to reach the maximum block was very short in patients in Group SA (p < 0.0001). There was a statistically significant difference between the groups in terms of motor block values (p < 0.0001). No fully paralysed sample was seen in Group SA even though there was a sufficient surgical anaesthesia. CONCLUSIONS: Saddle block has some advantages compared to spinal and epidural anaesthesia methods such as achieving adequate anaesthesia, stable haemodynami, the lower degree of motor blockage and no full blockage in patients. Saddle block is an the most optimal anaesthesia method for TURP operation.     

Competition between acetylcholine and a nondepolarizing muscle relaxant for binding to the postsynaptic receptors at the motor end plate: simulation of twitch strength and neuromuscular block

The goal of the study was to simulate twitch strength and neuromuscular block produced by nondepolarizing muscle relaxants. Methods: In the proposed model, affinities of the two binding sites at a single postsynaptic receptor for acetylcholine (A) and the muscle relaxant (D) define the formation of three complexes with A only, three complexes with D only, and two complexes with both A and D. Twitch strength was postulated to be a function of the receptors with both binding sites occupied by A, and two constants. Neuromuscular block (NMB) was calculated from NMB=1-twitch. Results: Stimulus-induced release of A results in rapid, but transient, changes in the concentrations of free A, the eight complexes, and the unoccupied receptors. Muscle relaxants that display either a congruous or an inverse pattern of affinities for the binding sites relative to those of A produce NMB vs. [D] curves with slightly different slopes but markedly different estimates for IC50. Depending on the number of activated receptors at the end plates of muscle fibers, the simulations represent the distributions of contracting fibers in a whole muscle. Conclusion: Simulations of competition between A and D for binding to two sites at a receptor reveal that the potencies of muscle relaxants, defined by IC50, and the slopes of the NMB vs. [D] curves depend on (1) the affinities of D for the two binding sites, (2) the orientation of the affinities relative to those of A, and (3) the affinities of A for the same two sites.     

Prospective randomised double-blind comparative study of rocuronium and pancuronium in adult patients scheduled for elective 'fast-track' cardiac surgery involving hypothermic cardiopulmonary bypass

The majority of cardiac anaesthetists in the UK use pancuronium for fast-track cardiac surgery. We compared the duration of action of pancuronium and rocuronium in patients undergoing fast-track hypothermic cardiopulmonary bypass and cardiac surgery. We determined whether patients would have had residual neuromuscular blockade at extubation. Twenty patients were randomly allocated to receive either pancuronium 0.1 mg x kg(-1) or rocuronium 1 mg x kg(-1). Neuromuscular function was assessed by acceleromyography; spontaneous recovery was evaluated by the train-of-four ratio measured at the adductor pollicis longus muscle. Median times to recover train-of-four ratio of 0.9 were 3 h 38 min for rocuronium and 7 h 52 min for pancuronium. The median difference in recovery times was 4 h 15 min (95% CI 2 h 30 min to 6 h 20 min; p = 0.0003 by Mann-Whitney test). None of the patients in the rocuronium group and seven of 10 patients in the pancuronium group had their extubations delayed because of residual neuromuscular blockade. Unless fast-track patients have neuromuscular function assessed before extubation, pancuronium should not be used.     

Post-dural puncture headache,intracranial air and obstetric anesthesia

Recently, a controversy has arisen as to whether air or saline should be recommended for the correct localization of the epidural space with the loss of resistance technique. I report a case of a previously healthy parturient who developed pneumocephalus and severe headache following the use of the loss of resistance to air (LORA) technique to identify the epidural space. This case report raises one more time the question about the safety of the LORA technique for labor analgesia.     

PCEA compared to continuous epidural infusion in an ultra-low-dose regimen for labor pain relief: a randomized study

BACKGROUND: Patient-controlled epidural analgesia, PCEA, has been introduced in obstetric analgesia during the past decade. Many studies have shown that the consumption of analgesic is reduced when the parturient requests her own doses. This study investigates whether this is also true when using an ultra-low-dose regimen. METHODS: Eighty parturients were prospectively randomized to have either continuous epidural infusion (CEI) with ropivacaine 1 mg ml-1 and sufentanil 0.5 micro g ml-1, 6 ml h-1, or patient-controlled epidural analgesia (PCEA) with 4 ml demand doses with 20 min' lockout. The epidural start dose was the same for the two groups, 8 ml of the study solution. Rescue bolus doses were given when needed and the continuous infusion could be increased, which gave the two groups the same maximum possible dose. The consumption of local ropivacaine in combination with sufentanil during labor was registered. Hourly assessments made throughout labor included pain intensity documented with visual analog score, VAS, the patient's opinion on epidural efficacy, motor block, pruritus and need for nitrous oxide. RESULTS: The PCEA group consumed 33% less of the study solution than the CEI group. Mean total consumption was 35 ml (SD 18.0) and 52 ml (SD 19.6), respectively. Mean hourly consumption was 5.2 ml h-1 (SD 2.54) in the PCEA group and 6.9 ml h-1 (SD 1.31) in the CEI group. There were no significant differences between the two groups in pain relief, epidural efficacy, side-effects or obstetric outcome. CONCLUSION: PCEA reduces doses compared to continuous infusion even when ultra-low-dose local anesthetic with opioid is used. The PCEA technique provides individual titration of doses to an acceptable degree of pain relief.     

Intrathecal hyperbaric bupivacaine 3 mg + fentanyl 10 microg for outpatient knee arthroscopy with tourniquet

BACKGROUND: Combination of local anesthetic and opioid enables the use of less spinal anesthetic and increases the success of anesthesia. Intrathecal opioid does not prolong motor recovery and thus should not delay discharge home. We hypothesized that 3 mg of hyperbaric bupivacaine with 10 microg of fentanyl permits fast-tracking or shorter stay in post anesthesia care unit (PACU), and earlier discharge home, compared with 4 mg of hyperbaric bupivacaine. METHODS: In this double-blind study, 100 outpatients undergoing knee arthroscopy received randomly either 4 mg of bupivacaine (B4) or 3 mg of bupivacaine + 10 microg fentanyl (B3F) intrathecally. The volume of 0.8 ml was injected at the L2/3 interspace over a 2-min period. A lateral decubitus position was maintained for 10 min. The sensory block was recorded by using thermal stimuli, and motor block was assessed according to a modified Bromage scale. Fast-tracking criteria were complete recovery of motor block, sensory block Th12 or lower and stable vital signs. RESULTS: One block (1%) failed. Motor recovery was faster in the B3F group: 60% of the patients recovered in 80 min or less compared with 28% in group B4 (P = 0.002). The PACU-time was shorter: 36 (10-103) vs. 55 (10-140) min, respectively (P = 0.005). Seventeen (B3F) vs. nine patients (B4) could bypass PACU (NS). Time to discharge home was similar in both groups. In the B3F group, 75% of the patients developed pruritus. CONCLUSION: Both solutions produced reliable spinal anesthesia for outpatient knee arthroscopy. The PACU-time was shorter in the bupivacaine-fentanyl group, but both groups reached home-readiness equally.     

Lidocaine versus ropivacaine for continuous interscalene brachial plexus block after open shoulder surgery

BACKGROUND: This study compared the postoperative infusion of 1% lidocaine and 0.2% ropivacaine for continuous interscalene analgesia in patients undergoing open shoulder surgery. METHODS: Forty patients undergoing open shoulder surgery received an interscalene brachial plexus block with 30 ml of either 1.5% lidocaine (n = 20) or 0.5% ropivacaine (n = 20), followed by a continuous patient-controlled interscalene analgesia with 1% lidocaine or 0.2% ropivacaine, respectively. A blinded observer recorded the quality of analgesia and recovery of motor function during the first 24 h of infusion. RESULTS: Onset of the block occurred after 7.5 (5-40) min with lidocaine and 30 (10-60) min with ropivacaine (P = 0.0005). Postoperative pain intensity was higher with lidocaine than ropivacaine for the first 8 h of infusion. The ratio between boluses given and demanded from the pump was 0.5 (0.13-0.7) with lidocaine and 0.7 (0.4-1.0) with ropivacaine (P = 0.005). Rescue IV tramadol was required during the first 24 h of infusion by 16 patients of the lidocaine group (84%) and eight patients of the ropivacaine group (46%) (P = 0.05). At the 16 h and 24 h observation times a larger proportion of patients receiving ropivacaine had complete regression of motor block (70% and 95%) than patients receiving lidocaine (50% and 55%) (P = 0.05 and P = 0.013, respectively). CONCLUSIONS: Although 1% lidocaine can be effectively used for postoperative patient-controlled interscalene analgesia, 0.2% ropivacaine provides better pain relief and motor function.     

Chronic lumbar epidural haematoma presenting with acute paraparesis

Summary ¶Chronic spinal epidural haematomas are very rare and have been reported to occur only in the lumbar region. They usually become symptomatic through radicular pain or neurogenic claudication. The epidural bleeding is thought to originate from a rupture of an epidural vein due to a sudden increase in intra-abdominal pressure or due to trauma.The patient reported on here developed acute paraparesis about 8 weeks after a mild fall on the buttocks. MRI showed a spinal epidural mass located dorsolaterally at the level of L3–L5. The mass was surgically removed. Histological and immunohistological studies disclosed an organised haematoma.The clinical, radiological and intra-operative features of this case are described, and the relevant literature is analysed.Published online October 20, 2003     

Zebrafish embryos express an orthologue of HERG and are sensitive toward a range of QT-prolonging drugs inducing severe arrhythmia

A wide range of drugs has been shown to prolong the QT interval of the electrocardiogram by blocking the pore-forming subunit of the rapidly activating delayed rectifier K+ channel, HERG (ether-à-go-go-related gene), sometimes leading to life-threatening arrhythmia. In this paper we describe cloning, sequence, and expression of the zebrafish orthologue of HERG, Zerg. Further, we studied effects of Zerg inhibition in zebrafish embryos caused by drugs or by an antisense approach. Zerg is expressed specifically in both heart chambers of zebrafish embryos, is composed of six transmembrane domains, and shows an especially high degree of amino acid conservation in the S6 and pore domain (99% identity). Several QT-prolonging drugs added to the bathing medium elicited bradycardia and arrhythmia in zebrafish embryos. The arrhythmia induced ranged from an atrioventricular 2:1 block, the ventricle beating half as often as the atrium, to more severe irregular arrhythmia with higher concentrations of the drugs. These effects were highly specific, reproducible, and rapid, e.g., 10 microM astemizole caused a 2:1 heartbeat within a minute after addition of the compound in all the embryos studied. Morpholino antisense oligonucleotides targeting Zerg were injected into zebrafish embryos and elicited similar dose-sensitive and specific arrhythmia as the QT-prolonging drugs, suggesting an evolutionarily conserved role for Erg in regulating heartbeat rate and rhythm. Further, we identified a mutation in the Per-Arnt-Sim domain of the Zerg channel in the breakdance mutant, also characterized by a 2:1 atrioventricular block. In conclusion, the zebrafish could be a tractable model organism for the study of Erg function and modulation but might also have a value in the field of cardiovascular pharmacology, e.g., as an early preclinical model for testing drugs under development for potential QT prolongation.