Anesthesia and analgesia
-
Anesthesia and analgesia · Feb 1998
Extension of sensory blockade after thoracic epidural administration of a test dose of lidocaine at three different levels.
To evaluate the relationship between the level of thoracic epidural injection and the extension of sensory blockade, we inserted radiopaque epidural catheters in 87 patients at the high (C7-T2, n = 28), mid (T3-5, n = 29) or low (T7-9, n = 30) thoracic levels. Fifteen minutes after the epidural administration of 60 mg of lidocaine, the mean (+/- SD) sensory block extension varied from 5.4 +/- 3.1 to 7.7 +/- 1.8 segments. The level of epidural puncture was a statistically significant factor in determining the cranial and caudal borders of sensory blockade (P = 0.0001, analysis of variance), but in determining for the total number of segments blocked. The number of blocked dermatomes located cranially of the puncture level increased significantly with descending injection site (P = 0.0001). We acquired chest radiographs in 61 patients to determine epidural catheter tip position. Direction of the epidural catheter tip was not a significant factor in determining the extension or borders of sensory blockade. We conclude that the extension of sensory blockade in thoracic epidural anesthesia is not influenced by the level of epidural puncture or catheter tip direction. There is, however, a more cranial spread of sensory blockade in the low thoracic region compared with the high thoracic region. ⋯ After evaluating the extension and pattern of sensory blockade in high, mid, and low thoracic epidural analgesia, the authors suggest that it is safe to use similar dosage regimens in all three regions, and that in high thoracic epidural analgesia, it is important to insert the epidural catheter at the level of the intended cranial border of blockade.
-
Anesthesia and analgesia · Feb 1998
The effects of red-cell scavenging, hemodilution, and active warming on allogenic blood requirements in patients undergoing hip or knee arthroplasty.
Since 1993, we have progressively adopted three techniques to reduce transfusion requirements during major orthopedic surgery: red-cell scavenging, acute normovolemic hemodilution, and active patient warming. We retrospectively evaluated all 821 elective hip and knee arthroplasties performed in our institution beginning with July 1993. Target minimal hematocrits were guided by patient ages and cardiovascular status. The first approximately 500-mL blood loss was replaced with crystalloid at a ratio of 3 mL for each milliliter of blood loss. Additional blood loss was replaced with colloid, hemodilution blood (when available), and scavenged red cells (when available). Allogenic transfusions were then administered as necessary to maintain target hematocrits, which were prospectively defined based on the patient ages and cardiovascular health. Univariate analysis was applied initially. Significant predictors of transfusion requirement were subsequently entered into a stepwise multiple regression to account for confounding factors, including age, type of anesthesia (regional versus general) and type of surgery (primary versus hardware replacement). Postoperative hemoglobin concentrations were similar over the years of study and among the patients given each treatment. During the study period, allogenic blood requirements decreased from 1.3 +/- 1.7 U/patient to 0.6 +/- 1.4 U/patient (mean +/- SD). Both univariate and regression analyses indicated that each treatment significantly reduced transfusion requirements (P < 0.05). We conclude that red-cell scavenging, hemodilution, and active cutaneous warming each reduce allogenic blood requirements during hip and knee arthroplasties. ⋯ We retrospectively evaluated three strategies to reduce overall blood loss: red-cell scavenging, acute normovolemic hemodilution, and active patient warming. During the study period, allogenic blood requirements decreased by a factor of 2. Each treatment contributed to this reduction. We therefore conclude that each treatment reduces allogenic blood requirements during hip and knee arthroplasties.
-
Anesthesia and analgesia · Feb 1998
Randomized Controlled Trial Clinical TrialIntravenous lidocaine speeds the return of bowel function, decreases postoperative pain, and shortens hospital stay in patients undergoing radical retropubic prostatectomy.
Postoperative ileus is a concern among surgical patients. Epidural anesthesia and analgesia with local anesthetics can decrease the duration of ileus. Significant systemic absorption of local anesthesia occurs during epidural use. In this study, we examined whether many of the beneficial effects on bowel function seen with epidural lidocaine are also present when the drug is given parenterally. Forty patients undergoing radical retropubic prostatectomy were studied with one half of the patients receiving a lidocaine bolus (1.5 mg/kg) and infusion (3 mg/min, unless weight <70 kg, then 2 mg/min); the other half received a saline infusion. A blind observer recorded the patient's daily pain score, the time the patient first experienced flatulence and had the first bowel movement, and the total use of analgesics. Lidocaine-treated patients first experienced flatulence in a significantly shorter time (P < 0.01) than control patients. Lidocaine patients' hospital stay was also significantly shorter (P < 0.05); on average, they spent 1.1 fewer days in the hospital. I.V. lidocaine initiated before anesthesia and continued 1 h postoperatively significantly sped up the return of bowel function. Lidocaine patients were also more comfortable postoperatively. Many of the bowel function benefits attributed to epidural lidocaine are also present when the drug is administered parenterally. Additionally, the length of hospital stay was reduced in lidocaine-treated patients. ⋯ This study prospectively examined whether I.V. lidocaine could affect the return of bowel function after radical prostate surgery. Lidocaine-treated patients had shorter hospital stays, less pain, and faster return of bowel function. In this population, lidocaine infusion can be a useful adjunct in anesthetic management.
-
Anesthesia and analgesia · Feb 1998
Randomized Controlled Trial Clinical TrialAdding sodium bicarbonate to lidocaine enhances the depth of epidural blockade.
It is controversial whether adding CO2 or sodium bicarbonate to local anesthetics enhances the depth of epidural blockade. Repeated electrical stimulation is a reliable test for assessing epidural analgesia and evokes temporal summation. We used this test to investigate the analgesic effect of lidocaine, with or without CO2 or bicarbonate. Twenty-four patients undergoing epidural blockade with 20 mL lidocaine 2% at L2-3 were randomly divided into three groups: lidocaine hydrochloride, lidocaine CO2, and lidocaine plus 2 mL sodium bicarbonate 8.4%. Pain threshold after repeated electrical stimulation (five impulses at 2 Hz), pinprick, and cold test were performed at S1 and L4. Motor block was assessed. The addition of bicarbonate resulted in higher pain thresholds (P < 0.0001), faster onset of action (P = 0.009), and higher degree of motor block (P = 0.004) compared with lidocaine hydrochloride. We found no significant differences between lidocaine CO2 and hydrochloride. Most of these results were not confirmed by pinprick and cold tests. We conclude that the addition of sodium bicarbonate to lidocaine enhances the depth of epidural blockade, increases inhibition of temporal summation, and hastens the onset of block. Pinprick and cold are inadequate tests for comparing drugs for epidural anesthesia. ⋯ We measured pain perception during epidural anesthesia by delivering electrical stimuli to the knee and foot. We found that the addition of sodium bicarbonate to the local anesthetic lidocaine enhances analgesia. We observed no effect of adding carbon dioxide to lidocaine.