Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2004
Comparative StudyThe mechanical properties of continuous spinal small-bore catheters.
Continuous spinal anesthesia (CSA) has a nearly 100-yr history. In situations of difficult removal of a CSA small-bore catheter, mechanical properties of the different catheters might be important, because breakage could occur. We compared 5 different CSA small-bore catheters, 22- to 28-gauge from 3 manufacturers, for tensile strength, tensile stress, distension, and yield strength. ⋯ The material characteristics of different CSA small-bore catheters for maximal tensile strength were: 22-gauge = 29.56 +/- 1.56 (mean +/- sd) Newton (N), 24-gauge = 16.77 +/- 1.61 N, 25-gauge = 9.20 +/- 0.48 N, 27-gauge = 4.61 +/- 0.25 N, 28-gauge = 5.07 +/- 0.59 N at room temperature. A strong correlation between maximal tensile strength and the outer diameter (r = 0.957, P < 0.001) and maximal tensile strength and the wall thickness (r = 0.9, P < 0.001) was observed. Although extrapolation from experimental studies to clinical routine should be made with care, our data suggest that catheters with higher-strength characteristics may reduce the risk of catheter breakage in patients, although clinical correlations are lacking.
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Anesthesia and analgesia · Dec 2004
Case ReportsIntrinsic spinal cord catheter placement: implications of new intractable pain in a patient with a spinal cord injury.
We present a case of new intractable flank pain after intrathecal infusion system placement in a 45-yr-old man with a history of a T12 spinal cord injury with dysesthetic leg pain. Pain after intrathecal infusion system placement was evaluated by magnetic resonance imaging and the catheter was found to be intraparenchymal. ⋯ Increased vigilance is warranted when caring for paraplegic patients. When new pain persists, intrathecal medication tapering should be considered.
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Anesthesia and analgesia · Dec 2004
Ventricular fibrillation median frequency may not be useful for monitoring during cardiac arrest treated with endothelin-1 or epinephrine.
In this study, we evaluated whether median fibrillation frequency (MF) and mean fibrillation amplitude (AMP) reflect coronary perfusion pressure (CoPP) and predict successful defibrillation. MF, AMP, and CoPP were measured during prolonged ventricular fibrillation (VF) cardiac arrest and resuscitation in pigs. After 5 min of VF, cardiopulmonary resuscitation was started. ⋯ In a nonparametric spectral analysis of the individual MF versus CoPP and AMP versus CoPP curves, we found no link between the different curves in different animals or therapies. No difference was found in MF in pigs with ROSC (n = 8) compared with animals not achieving ROSC (n = 23) immediately before defibrillation (P = 0.85). Our data suggest that, in prolonged VF cardiac arrest, MF and AMP might not be useful tools to reflect myocardial perfusion.
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Anesthesia and analgesia · Dec 2004
Measuring depth of sedation with auditory evoked potentials during controlled infusion of propofol and remifentanil in healthy volunteers.
Avoiding excessively deep levels of sedation is a major problem in intensive care patients. We studied whether clinically relevant levels of sedation can be objectively assessed using long latency auditory evoked potentials. We measured the auditory evoked potentials at 100 ms after the stimulus (N100) in 10 healthy volunteers during stepwise increasing, clinically relevant levels of sedation (Ramsay score [RS] 2-4). ⋯ During both propofol-induced and propofol/remifentanil-induced sedation, the N100 amplitude decreased similarly without an effect on the latencies as the level of sedation increased from Ramsay score 2 to Ramsay score 4 (P < 0.01). At the same clinical level of sedation, propofol plasma concentrations were larger when sedation was achieved by propofol alone (propofol versus propofol/remifentanil, RS 3: 2.12 mug/mL +/- 0.51 versus 1.32 +/- 0.43, P < 0.01; RS 4: 3.37 +/- 0.47 versus 1.86 +/- 0.34, P < 0.01). Our results suggest that long latency auditory evoked potentials provide an objective electrophysiological analog to the clinical assessment of sedation independent of the sedation regime used.
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Anesthesia and analgesia · Dec 2004
Comparative StudyA comparison of postoperative pain control in patients after right lobe donor hepatectomy and major hepatic resection for tumor.
After initiating a living donor liver transplant program at our institution, we observed that donor patients experienced significant postoperative pain despite the use of thoracic patient-controlled epidural analgesia (PCEA) infusion catheters. We retrospectively compared patients who underwent right lobe donor hepatectomy (RLDH, n = 15) with patients who had undergone major hepatic resection for tumor (MHRT, n = 15) to elucidate the cause for this observation. All patients had preoperative thoracic epidural catheters placed, and both groups had similar surgical exposure. ⋯ There was no significant difference between patient groups for the amount of bupivacaine and volume of PCEA solution administered. These observations may be explained, in part, by the longer duration of surgery in the RLDH group. The possible role of preemptive analgesia via PCEA infusion and better perioperative teaching of PCEA use are discussed; these may lead to improved early postoperative pain control in RLDH patients.