Anesthesia and analgesia
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Anesthesia and analgesia · Oct 2001
Randomized Controlled Trial Clinical TrialThe placement of the epidural catheter at the predicted site by electrical stimulation test.
More accurate segmental and sagittal positioning of the epidural catheter tip is required for the success of continuous epidural analgesia, spinal cord monitoring, and percutaneous epidural spinal cord stimulation. We examined the usefulness of an electrical stimulation test for verifying the proper placement of the epidural catheter tip at the predicted site in the posterior epidural space by using a locally developed epidural catheter with electrodes at its tip. The test included the observation of segmental bilateral muscle twitches and the patient's report of feeling in the region stimulated by moving the epidural catheter electrode back and forth and changing the direction of the bevel of the Tuohy needle. The success rate of midline placement at the required spinal segment was significantly more frequent (99%; P < 0.001) in the group (n = 289) receiving the electrical stimulation test compared with the group (n = 277) not receiving the test (success rate 57%). The results indicate the usefulness of this method. We concluded that the electrical stimulation test is effective for verifying the proper placement of the catheter electrode tip. ⋯ Ideally the epidural catheter tip should be positioned in the posterior epidural space near the midline. We concluded that the electrical stimulation test is effective for verifying the proper placement of the catheter electrode tip.
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Anesthesia and analgesia · Oct 2001
Clinical TrialThe continuous femoral nerve block catheter for postoperative analgesia: bacterial colonization, infectious rate and adverse effects.
We investigated the incidence of bacterial and vascular or neurological complications resulting from femoral nerve catheters used for postoperative analgesia. Patients requiring continuous femoral blockade were consecutively included. Using surgical aseptic procedure, 211 femoral nerve catheters were placed (short-beveled insulated needle, peripheral nerve stimulator). After 48 h, each catheter was removed and semiquantitative bacteriological cultures were performed on each distal catheter tip. Postoperative analgesia and antibiotics were standardized. All complications during the insertion of the catheters and postoperatively (after 48 h and 6 wk) were noted. Few initial complications with no immediate or delayed complications were noted (20 difficult insertions, 3 impossible injections, 3 ineffective catheters, and 12 vascular punctures). After 48 h, 208 catheters were analyzed; 57% had positive bacterial colonization (with a single organism in 53%). The most frequent organisms were Staphylococcus epidermidis (71%), Enterococcus (10%), and Klebsiella (4%). Neither cellulitis nor abscess occurred. Three transitory bacteremias likely related to the catheter occurred. After 6 wk, no septic complications were noted. One femoral paresthesia, partially recovered 1 yr later, was noted. We conclude that the risk of bacterial complications is small with femoral nerve catheters, although the rate of colonization is frequent. ⋯ In this prospective study, continuous femoral nerve catheters were effective for postoperative analgesia but had a frequent rate of bacterial catheter colonization. We found no serious infections after short-term (2-day) infusion. Side effects were few, but one nerve injury occurred.
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Anesthesia and analgesia · Oct 2001
Clinical TrialJugular bulb oxyhemoglobin desaturation, S100beta, and neurologic and cognitive outcomes after coronary artery surgery.
We reported that a decline in cognitive performance 3 mo after coronary artery bypass grafting surgery is associated with palpable aortic atheroma, but not postoperative jugular bulb oxyhemoglobin saturation (SjO2) <50%. However, the effect of SjO2 on clinical neurologic findings is not known. S100beta is a possible surrogate biochemical marker of brain injury, and we report here the scored clinical neurologic findings in 98 patients from our previous study in relation to SjO2, cognitive performance, aortic atheroma, and S100beta. Patients underwent a scored neurologic examination and cognitive assessment the day before and 3 mo after coronary artery bypass grafting surgery. Intraoperatively, intermittent blood sampling was performed, and postoperatively, the area under the curve describing SjO2 <50% in relation to time was calculated from continuous jugular bulb reflectance oximetry. Palpation was used to assess the ascending aorta for the presence of atheroma. The jugular bulb concentration of S100beta was measured 6 h after completion of surgery. The neurologic score 3 mo after surgery did not correlate with either intra- or postoperative SjO2 (r = 0.111, P = 0.278; and r = -0.074, P = 0.467, respectively). The main determinant of neurologic score at 3 mo was the preoperative neurologic score (r(2) = 0.63, P < 0.001), whereas palpable atheroma of the ascending aorta made a small but significant contribution (r(2) = 0.034, P = 0.004). Neurologic and cognitive scores correlated before surgery (r = 0.226, P = 0.022) and at 3 mo after surgery (r = 0.348, P < 0.001). A preoperative neurologic deficit of two or more had a small but significant negative effect on cognitive performance at 3 mo (standardized beta = -0.097, P = 0.018). There was a significant univariate correlation between S100beta and the 3-mo neurologic score (r = -0.232, P < 0.05), but not a multivariate correlation (beta = -0.090, P = 0.156). ⋯ Intraoperative jugular bulb oxyhemoglobin saturation (SjO2) and postoperative SjO2 <50% do not have an important influence on long-term neurologic outcome after coronary artery bypass graft surgery. Subtle preoperative neurology is associated with long-term cognitive decline, and aortic atheroma is a risk factor for both cognitive and neurologic decline.
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Anesthesia and analgesia · Oct 2001
Clinical TrialThe pharmacokinetics of epidural ropivacaine in infants and young children.
The pharmacokinetic variables of ropivacaine were characterized after epidural bolus injection in pediatric patients. The subjects, 7 infants (aged 3-11 mo) and 11 young children (aged 12-48 mo), received 1.7 mg/kg of ropivacaine via a lumbar epidural catheter. Total plasma concentrations of ropivacaine measured over 24 h were assayed by high-pressure liquid chromatography, and pharmacokinetic modeling was performed by Nonlinear Mixed Effects Modeling analysis. The median peak venous plasma concentrations (C(max)) in infants and young children were 610 microg/L (interquartile range [IQR], 550-725 microg/L) and 640 microg/L (IQR, 540-750 microg/L), respectively. The median times to maximum plasma ropivacaine concentration (T(max)) were 60 min (IQR, 60-120 min) in infants and 60 min (IQR, 30-90 min) in young children. There were no statistical differences between median values of C(max) and T(max) between infants and young children. The calculated clearance (CL) in infants was 4.26 mL x min(-1) x kg(-1) (9% coefficient of variation), and in young children it was 6.15 mL x min(-1) x kg(-1) (11% coefficient of variation). The CL for infants was significantly less than the CL for young children (P < 0.01). The volume of distribution was estimated to be 2370 mL/kg (9% coefficient of variation) for both young children and infants. No systemic toxicity was observed in either group. ⋯ This study revealed that the pharmacokinetic variables of lumbar epidural bolus ropivacaine in pediatric patients aged 3 to 48 mo are similar to those of adults, except that drug clearance was less in infants compared with older children.
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Anesthesia and analgesia · Oct 2001
Clinical TrialThe optimal length of insertion of central venous catheters for pediatric patients.
Incorrect positioning of central venous catheters (CVC) in infants and children may lead to serious complications such as perforation of the heart or great vessels. CVC position is not usually assessed until the first postoperative chest radiograph, potentially leaving malposition undetected for several hours. We studied a series of 452 right internal jugular and subclavian catheter placements in infants and children undergoing surgery for congenital heart disease, and measured the distance from the skin insertion site to the radiographic junction of the superior vena cava and right atrium (RA). Based on these data, the following formulae predict that a CVC will be positioned above the RA 97% of the time: correct length of insertion (cm) = (height in cm/10) - 1 for patients < or =100 cm in height, and (height in cm/10) - 2 for patients >100 cm in height. Weight-based recommendations were also developed which predict placement of CVC above the RA 98% of the time. ⋯ This study assessed central venous catheter placement in 452 infants and children undergoing cardiac surgery. Simple, clinically useful guidelines based on height and weight were developed to prevent malposition of these catheters, which may cause serious complications such as perforation of the heart or great vessels.