Hugh W. Allen

Peripheral nerve blocks improve analgesia after total knee replacement surgery.

Total knee replacement (TKR) produces severe postoperative pain.Peripheral nerve blocks can be used as analgesic adjuncts for TKR, but the efficacy of femoral nerve blocks alone is controversial. The sciatic nerve innervates posterior regions of the knee; thus, performance of both sciatic and femoral nerve blocks may be necessary to improve analgesia after TKR. We performed this study to determine whether peripheral nerve blocks improve analgesia after TKR. In a randomized, double-blind fashion, 36 patients undergoing TKR received either femoral, sciatic-femoral, or sham nerve blocks after a standardized spinal anesthetic. Further postoperative analgesia was provided by patient-controlled IV morphine and ketorolac. Pain at rest and with physical therapy, morphine use, nausea, pruritus, sedation, and patient satisfaction were assessed. Patients receiving peripheral nerve blocks reported better analgesia at rest for at least 8 h after transfer to the hospital ward (P < 0.05). Morphine use was decreased by approximately 50% in the peripheral nerve block groups until the second postoperative day (P < 0.02). Side effect profiles and patient satisfaction were similar between groups. We conclude that femoral nerve blocks improve analgesia and decrease morphine use after TKR. The addition of a sciatic nerve block to the femoral nerve block did not further improve analgesic efficacy. Implications: Performance of femoral nerve blocks improves analgesia and decreases the need for morphine after total knee replacement surgery. The addition of a sciatic nerve block to the femoral nerve block does not provide additional benefits. (Anesth Analg 1998;87:93-7)

Patient-controlled epidural analgesia with bupivacaine and fentanyl on hospital wards : Prospective experience with 1,030 surgical patients

Background The efficacy and safety of patient‐controlled yepidural analgesia (PCEA) for postoperative analgesia on hospital wards was studied. Methods Postoperative analgesia was provided for 1,030 patients with PCEA using 0.05% bupivacaine and fentanyl, 4 micro gram/ml, in a standardized manner. Patients were seen at least twice a day by the staff of the anesthesia pain management service. Prospectively gathered data included verbal pain scores at rest and activity (0–10); consumption of bupivacaine and fentanyl; and incidences of pruritus, nausea, sedation, hypotension, motor block, and respiratory depression. Descriptive statistics were used. Risk factors for side effects were determined using logistic regression. Results The study included 552 women and 477 men who underwent a median (mode) of 3 (2) days of PCEA. Their mean age was 59 +/‐ 16 yr and their mean weight was 76 +/‐ 19 kg. There were 454 abdominal, 165 gynecologic, 126 urologic, 108 vascular, 90 thoracic, 83 orthopedic, and 4 plastic surgical procedures. Median (mode) pain scores were 1 (0) at rest and 4 (5) with activity on postoperative day 1. Incidences of side effects were 16.7% (pruritus), 14.8% (nausea), 13.2% (sedation), 6.8% (hypotension), 2% (motor block), and 0.3% (respiratory depression). Reasons for termination of PCEA were elective (82%), displaced epidural catheter (12%), anticoagulation (3%), infection (1%), side effects (1%), inadequate analgesia (1%), and other (< 1%). Risk factors for side effects were female sex, patient weight < 73 kg, patient age < 58 yr, bupivacaine and fentanyl consumption > 9 ml/h, use of analgesic adjuncts, and lumbar placement of epidural catheters. Conclusion Patient‐controlled epidural analgesia provides effective and safe postoperative analgesia on hospital wards.

Dose-response characteristics of spinal bupivacaine in volunteers : Clinical implications for ambulatory anesthesia

Background Small doses of bupivacaine may be a reasonable choice for spinal anesthesia for patients having ambulatory surgery. However, few dose‐response data are available to guide the selection of reasonable doses of bupivacaine for different ambulatory procedures. Methods Eight volunteers per group were randomized to receive 3.75, 7.5, or 11.25 mg of 0.75% bupivacaine with 8.25% dextrose in a double‐blind manner. Sensory block was assessed with pinprick, transcutaneous electrical stimulation equivalent to surgical incision at the ankle, knee, pubis, and umbilicus, and with duration of tolerance to pneumatic thigh tourniquet. Motor block at the quadriceps and gastrocnemius muscles was assessed with isometric force dynamometry. Times until recovery from spinal anesthesia were recorded. Dose‐response relationships were determined by linear regressions. Mean (95% confidence intervals) for durations of sensory and motor block per milligram of bupivacaine administered were calculated from linear regressions. Results Significant dose‐response relationships (P < 0.006) were determined for sensory block, motor block, and time until recovery (R from 0.6 to 0.9). Within the range of doses studied, each additional milligram of bupivacaine was associated with an increase in duration of tolerance to transcutaneous electrical stimulation of 10 (7 to 13) min, an increase in tolerance to tourniquet of 7 (2 to 11) min, an increase in duration of motor block of 8 (5 to 12) min, and an increase in time until recovery of 21 (17 to 25) min. Conclusions These dose‐response data may guide the selection of reasonable doses of bupivacaine for various outpatient procedures, although individual responses vary.

Fentanyl Prolongs Lidocaine Spinal Anesthesia Without Prolonging Recovery

Lidocaine spinal anesthesia is a popular anesthetic for short procedures due to its brief duration.The addition of fentanyl may improve the quality and duration of lidocaine spinal anesthesia. Eight volunteers received plain lidocaine 5% in dextrose (50 mg) both with and without 20 micro gram of fentanyl in a randomized, double-blind, cross-over fashion. Sensory analgesia was assessed with pinprick, cold, touch, transcutaneous electrical stimulation equivalent to surgical incision, and duration of tolerance of pneumatic thigh tourniquet. Motor block was assessed with isometric force dynamometry. Regression of pinprick, touch, and cold was prolonged with fentanyl. Duration of tolerance of electrical stimulation at the umbilicus, hip, knee, and ankle was increased with fentanyl (181% increase from plain lidocaine on average; P < 0.01). Duration of tolerance of tourniquet-induced pain was increased by an average of 48% with addition of fentanyl (P = 0.02). Neither motor block nor time to void was prolonged with fentanyl. Pruritus occurred in all subjects receiving fentanyl but was treated easily and were well tolerated. We recommend the addition of 20 micro gram of fentanyl to lidocaine spinal anesthesia as a means to improve duration of sensory anesthesia without prolonging recovery of motor function or time to micturition. (Anesth Analg 1995;80:730-4)

Near-total esophagectomy: the influence of standardized multimodal management and intraoperative fluid restriction.

Background and Objectives Esophagectomy can be associated with high morbidity and mortality. We present our experience managing these patients using a standardized multimodal approach that emphasizes intraoperative fluid restriction and early extubation. Methods This case series includes 56 consecutive patients over a 2-year period (1999-2000) that underwent near-total esophagectomy at a high-volume center. Surgical approach was determined by patient and tumor characteristics; intraoperative fluid replacement was conservative; and patient-controlled epidural anesthesia/analgesia was used to promote early extubation, enteral feeding, and ambulation. Results Overall morbidity was 18%; in-hospital and 30-day mortality was zero. Intraoperative urinary volume averaged 0.57 mL/kg/h. No patient developed postoperative renal dysfunction or pulmonary complications. All patients were extubated in the operating room. First ambulation averaged 1.6 days after surgery. Median intensive care unit and hospital stays were 1 and 10 days, respectively. Side effects from thoracic epidural analgesia were minimal. Conclusions Significant reduction in esophagectomy-related morbidity is possible using a standardized multimodal approach in routine clinical practice. Intraoperative fluid restriction may facilitate early extubation and reduce pulmonary complications without compromising renal function. This preliminary observation warrants further study in a randomized clinical trial.

A comparison of epidural levobupivacaine 0.75% with racemic bupivacaine for lower abdominal surgery.

Levobupivacaine, the S(−) isomer of bupivacaine, is less cardiotoxic than racemic bupivacaine. In this prospective, randomized, double-blinded study of epidural anesthesia, the onset, extent, and duration of sensory and motor block produced by 0.75% levobupivacaine (20 mL, 150 mg) was compared with that of 0.75% racemic bupivacaine in 56 patients undergoing elective lower abdominal surgery. The time to onset of adequate sensory block (T10 dermatome) was similar in both treatment groups (13.6 ± 5.6 min for levobupivacaine and 14.0 ± 9.9 min for bupivacaine), with an average peak block height of T5 reached at 24.3 ± 9.4 and 26.5 ± 13.2 min, respectively. Time to complete regression of sensory block was significantly longer with levobupivacaine (550.6 ± 87.6 min) than bupivacaine (505.9 ± 71.1 min) (P = 0.016). Abdominal muscle relaxation was adequate for the scheduled procedure in all patients, and there were no significant differences between the groups in rectus abdominis muscle scores (P = 0.386) and quality of muscle relaxation as determined by the surgeon and anesthesiologist (P = 0.505 and 0.074, respectively). In conclusion, both 0.75% levobupivacaine and 0.75% bupivacaine produced effective epidural anesthesia and their effects were clinically indistinguishable. Implications: The results of this study indicate that the sensory and motor block produced by 0.75% levobupivacaine is equivalent to that of 0.75% racemic bupivacaine. Both local anesthetics are well tolerated and effective in producing epidural anesthesia for patients undergoing lower abdominal surgery.

Intravenous versus epidural administration of hydromorphone : effects on analgesia and recovery after radical retropubic prostatectomy

Background It remains unclear whether epidural administration of hydromorphone results in spinal analgesia or clinical benefit when compared with intravenous administration. Therefore, we undertook this study to determine whether epidural administration of hydromorphone resulted in decreased opioid requirement, improved analgesia, reduced side effects, more rapid return of gastrointestinal function, or shorter duration of hospital stay than intravenous administration. Methods Sixteen patients undergoing radical retropubic prostatectomy were randomized in a double‐blind manner to receive either intravenous or epidural hydromorphone via patient‐controlled analgesia (PCA) for postoperative analgesia. All patients underwent a standardized combined epidural and general anesthetic and all received ketorolac for 72 h postoperatively. To decrease variability, patients were cared for according to a standardized protocol and were deemed ready for discharge according to prospectively defined criteria. Results Patients in the intravenous PCA group required approximately twice as much opioid than the epidural PCA group (P < 0.008), but there were no differences between groups in pain scores or patient satisfaction. Epidural administration resulted in a greater incidence of pruritus (P ‐ 0.02). Gastrointestinal function recovered quickly in all patients with little variation, and there were no differences between groups. All patients were deemed ready for discharge by the third postoperative day, and removal of surgical drains was the last discharge criterion reached in all patients. Conclusions Our results indicate that epidural administration of hydromorphone results in spinally mediated analgesia. However, epidural administration did not provide significant benefits in terms of postoperative analgesia, recovery of gastrointestinal function, or duration of hospitalization. Furthermore, we suggest that radical retropubic prostatectomy no longer be used as a model to assess the effects of analgesic technique on postoperative recovery, because control of discharge criteria revealed that hospital discharge was primarily dependent on removal of surgical drains.

Comparison of 5% with Dextrose, 1.5% with Dextrose, and 1.5% Dextrose-Free Lidocaine Solutions for Spinal Anesthesia in Human Volunteers

The use of lidocaine in concentrations less than 5% for spinal anesthesia may be advantageous but has not been carefully studied.Lidocaine 50 mg (1.5% with dextrose and 1.5% dextrose-free) was administered to eight volunteers in a randomized, double blind, cross-over fashion. All of these subjects had previously received 5% lidocaine with dextrose using the same experimental protocol. Sensory analgesia was assessed with pinprick, transcutaneous electrical stimulation (TES) equivalent to surgical incision, and duration of tolerance of pneumatic thigh tourniquet. Motor block was assessed with isometric force dynamometry. Peak dermatomal level was the highest and duration until regression of pinprick the longest with the 5% solution (P < 0.05). Duration of tolerance to TES was increased (33 +/- 10 min) with the 5% solution (P < 0.04). Duration of tolerance to tourniquet pain was increased (11 +/- 3 min) with the 5% solution (P < 0.02). Duration of motor block was increased (45 +/- 9 min) with the 5% and the 1.5% without dextrose solutions (P < 0.04). Time to void was increased (33 +/- 5 min) with the 5% solution (P < 0.03). In conclusion, the use of different solutions of lidocaine for spinal anesthesia results in significant differences in sensory and motor block and time until recovery of micturition. (Anesth Analg 1995;81:697-702)

A comparison of levobupivacaine 0.125%, fentanyl 4 μg/mL, or their combination for patient-controlled epidural analgesia after major orthopedic surgery

UNLABELLED Levobupivacaine, the isolated S(-) isomer of bupivacaine, is less cardiotoxic than racemic bupivacaine in animal studies. We studied the effectiveness of patient-controlled epidural analgesia (PCEA) with either levobupivacaine 0.125% or fentanyl 4 microg/mL alone, or a combination of levobupivacaine and fentanyl in 65 patients after total joint arthroplasty in a prospective, random, double-blinded fashion. Intraoperatively, all patients received 20 mL of 0.75% levobupivacaine. Study medication was infused at an initial rate of 4 mL/h, with additional medication available on patient demand (2 mL/10 min). The combination of levobupivacaine and fentanyl produced better analgesia (longer time to first PCEA request; P = 0.007 combination versus fentanyl and P = 0.006 combination versus levobupivacaine) than either drug alone. Patients in the levobupivacaine groups had appreciable sensory blockade to pinprick with minimal motor impairment. Resting and dynamic visual analog scale pain scores were lower in the combination group than in the plain fentanyl group at 6 (P = 0.022 and 0.036) and 12 h (P = 0.002 and 0.001). The 24-h overall patient- and investigator-rated visual analog scale pain scores were also lower in the combination group (resting P = 0.007, dynamic P = 0.005). There was no significant difference among the groups in the incidence of postoperative nausea (26.2%), pruritus (9.2%), hypotension (23.1%), or sedation (0%). We conclude that the analgesic effects of levobupivacaine 0.125% and fentanyl (4 microg/mL) are additive and beneficial for the management of orthopedic surgical pain by the PCEA method. Patients in this study began demand-dosing later, reported lower pain scores, and had no greater risk of adverse events than those who were given either levobupivacaine or fentanyl alone. IMPLICATIONS We demonstrated a significant additive effect of the combination of levobupivacaine (0.125%) and fentanyl (4 microg/mL), compared with either drug alone, when using patient-controlled epidural analgesia in patients after total joint arthroplasty.

A comparison of epidural levobupivacaine 0.5% with or without epinephrine for lumbar spine surgery.

Levobupivacaine, the S(−) isomer of bupivacaine, is less cardiotoxic than racemic bupivacaine. In this prospective, randomized, double-blinded study of epidural anesthesia, we compared the onset, extent, and duration of sensory and motor blockade produced by plain 0.5% levobupivacaine (15 mL, 75 mg) with that of 0.5% levobupivacaine with the addition of 1:400,000 or 1:200,000 epinephrine in 117 patients undergoing elective spine surgery. The time to onset of adequate sensory block (T10 dermatome) was similar in all groups (12.4 ± 6.6 min for plain levobupivacaine, 13.9 ± 7.9 min for levobupivacaine with 1:400,000 epinephrine, and 12.7 ± 4.9 min for levobupivacaine with 1:200,000 epinephrine), with an average peak block height of T5. Time to complete regression of sensory blockade was also similar between groups (357 ± 119 min for plain levobupivacaine, 378 ± 98 min for levobupivacaine with 1:400,000 epinephrine, and 348 ± 80 min for levobupivacaine with 1:200,000 epinephrine). Peak serum levobupivacaine levels were reduced in each of the epinephrine-containing groups. We conclude that 0.5% levobupivacaine with or without 1:200,000 or 1:400,000 epinephrine produced effective epidural anesthesia in patients having lumbar spine surgery. Epinephrine 1:400,000 is as effective as 1:200,000 in reducing the resultant serum levobupivacaine levels after epidural anesthesia.