Anesthesia and analgesia
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Anesthesia and analgesia · Aug 2001
The prevalence and predictive value of abnormal preoperative laboratory tests in elderly surgical patients.
Because data to determine which preoperative laboratory tests are important in elderly surgical patients are limited, we performed a prospective cohort study to evaluate the prevalence and predictive value of abnormal preoperative laboratory tests in consecutive patients > or =70 yr old who were undergoing noncardiac surgery. Patients presenting for surgery requiring only local anesthesia or monitored anesthesia care were excluded. Preoperative risk factors and laboratory test results were measured and evaluated for their association with the occurrence of predefined in-hospital postoperative adverse outcomes. In 544 patients, the prevalence of preoperative electrolytes and platelet count abnormalities (<115 x10(9)/L) was small (0.5%-5%), and abnormal creatinine (>1.5 mg/dL), hemoglobin (<10 g/dL), and glucose (>200 mg/dL) values were 12%, 10%, and 7%, respectively. Univariate predictors for adverse outcome of abnormal sodium and creatinine were not as predictive as ASA classification and surgical risk. By multivariate logistic regression, only ASA classification (>II) (odds ratio [OR], 2.55; 95% confidence interval [CI], 1.56-4.19; P < 0.001) and surgical risk (OR, 3.48; 95% CI, 2.31-5.23; P < 0.001) were significant independent predictors of postoperative adverse outcomes. The prevalence of abnormal preoperative electrolyte values and thrombocytopenia was small and had low predictive values. Although more prevalent, abnormal hemoglobin, creatinine, and glucose values were also not predictive of postoperative adverse outcomes. Routine preoperative testing for hemoglobin, creatinine, glucose, and electrolytes on the basis of age alone may not be indicated in geriatric patients. Rather, selective laboratory testing, as indicated by history and physical examination, which will determine patient's comorbidities and surgical risk, seems to be indicated. ⋯ The prevalence of abnormal preoperative electrolyte values and thrombocytopenia was small and had low predictive values. Although more prevalent, abnormal hemoglobin, creatinine, and glucose values were also not predictive of postoperative adverse outcomes. Routine preoperative testing for hemoglobin, creatinine, glucose, and electrolytes on the basis of age alone may not be indicated in geriatric patients. Rather, selective laboratory testing, as indicated by history and physical examination, which will determine patient's comorbidities and surgical risk, seems to be indicated.
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Anesthesia and analgesia · Aug 2001
The effect of intrathecal analgesia on the success of external cephalic version.
External cephalic version (ECV), the procedure whereby a fetus in the breech position is converted to vertex, is often performed to avoid an operative delivery. Potential benefits of epidural and spinal anesthesia for this procedure are controversial. Several previous studies have evaluated the use of epidural anesthesia with varying results. We sought to determine whether analgesia produced by subarachnoid sufentanil would safely improve the success of ECV. Patients who received subarachnoid analgesia (n = 20) were compared with those who did not (n = 15) in regard to success of ECV, level of pain during ECV, and satisfaction. ECV was successful in 21 patients (60%), with more frequent success in women who received spinal analgesia as compared with those who did not (80% vs 33%, respectively; P = 0.005). Patients who received spinals also reported smaller pain scores and were more satisfied with ECV. None of the women who received spinal analgesia developed a postdural puncture headache, and the only case of fetal bradycardia occurred in a patient who did not receive spinal analgesia. More profound patient comfort after spinal analgesia may have permitted greater manipulation of the abdomen during ECV, thus improving success rates of ECV without increasing risk. ⋯ The success of external cephalic version (ECV) was compared in women who received spinal analgesia and those who did not. Successful ECV occurred more frequently in those women who received spinal analgesia. Because term singleton pregnancies associated with breech position usually require cesarean delivery, an increase in success of ECV may decrease the number of cesarean deliveries performed.
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Anesthesia and analgesia · Aug 2001
A study of the paravertebral anatomy for ultrasound-guided posterior lumbar plexus block.
We investigated the feasibility of posterior paravertebral sonography as a basis for ultrasound-guided posterior lumbar plexus blockades. Posterior paravertebral sonography proved to be a reliable as well as accurate imaging procedure for visualization of the lumbar paravertebral region except the lumbar plexus.
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Anesthesia and analgesia · Aug 2001
An evaluation of the infraclavicular block via a modified approach of the Raj technique.
Infraclavicular plexus block has recently become a technique of increasing interest. However, no approach has provided easily identifiable landmarks, good conditions for catheter placement, and lack of complications (mainly pneumothorax). We describe a modified approach of the Raj technique based on the identification of the anterior acromial process, jugular notch, and emergence of the axillary artery within the axillary fossa, with the arm abducted to 90 degrees and elevated by approximately 30 degrees. We evaluated the clinical characteristics of this approach by injecting 40 to 50 mL of ropivacaine 0.6% in 150 patients scheduled for elective surgery of the forearm, wrist, or hand. Success was defined as a sensory block of the 5 nerves with territories distal to the elbow within 30 min after performing the block. The success rate was 97% when a distal response (flexion or extension of the wrist or fingers) was elicited and 44% when a proximal (contraction of the triceps, biceps) was obtained using a nerve stimulator. Complications were rare: aspiration of blood was seen in 2% of patients and hematoma was seen at the puncture site in 0.6%; no pneumothorax occurred. Eleven patients (7%) complained of some pain during the procedure. We conclude that the modified approach of the Raj technique for infraclavicular block is very effective when a distal nerve stimulator response is obtained with a small complication rate and a high degree of patient satisfaction. ⋯ We describe a modified approach of the Raj technique for the infraclavicular brachial plexus. The elicitation of a distal nerve stimulator response is associated with a high success rate, a low incidence of complications and a high degree of patient satisfaction.
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Anesthesia and analgesia · Aug 2001
The effect of large-dose intrathecal opioids on the autonomic nervous system.
Decreases in blood pressure after the spinal injection of opioids suggest that intrathecal (IT) opioids may have a sympatholytic effect similar to that of local anesthetic drugs. We compared two groups of patients aged 10-16 yr (n = 10 in each group). Group One (IT group) received IT opioids. Group Two (Epidural group) received 0.5% bupivacaine epidurally. The sympathetic effects of IT opioids and epidural bupivacaine were monitored by the changes in toe relative to calf temperature and by the changes in pulse wave gradients with digital plethysmography. Changes in temperature gradients comparing calf to toe and increases in pulse amplitude indicate vasodilatation caused by sympathetic blockade in this model. Calf to toe temperature gradients (Deltacalf-Deltatoe) were evaluated by subtracting the two measurements. Pulse wave plethysmography was recorded before and after spinal and epidural injection at intervals of 10 min for 40 min. All patients demonstrated changes in their calf to toe gradients after IT and epidural injections (-3.2 +/- 1.6). Systolic blood pressure decreased from a mean of 70 +/- 15 mm Hg to 55 +/- 10 mm Hg. Pulse wave plethysmography amplitude increased after the intrathecal opioid and epidural bupivacaine injection similarly. We conclude that the increases in pulse wave amplitude and decreases in calf-toe gradients indicate a sympatholytic effect after IT opioids similar to that of local anesthetics. ⋯ The sympatholytic effects of neuraxial opioids were compared with those of local anesthetics. Two groups of patients were assigned to receive a neuraxial opioid or bupivacaine. Our results demonstrate that opioids cause hypotension and peripheral vasodilatation similar to bupivacaine. This finding suggests that neuraxial opioids have a sympatholytic effect comparable to that of local anesthetic drugs.