The effect of tourniquet release time on the analgesic efficacy of intraarticular morphine after arthroscopic knee surgery.

A randomized, controlled study was conducted in patients undergoing elective arthroscopic knee surgery to assess the effects of tourniquet release time on analgesia after intraarticular (I.A.) injection of morphine. Standardized general anesthetic and surgical techniques were used for all patients, including a thigh tourniquet inflated at pressures between 300 and 350 mm Hg. At the conclusion of the arthroscopic procedure, 5 mg morphine in 25 mL saline was administered I.A. Patients were then randomized to one of two treatment groups. In Group 1 (n = 20), the tourniquet was kept inflated for 10 min after I.A. injection, whereas in Group 2 (n = 20), the tourniquet was deflated immediately after I.A. injection. Postoperative pain was assessed using a visual analog scale in the recovery room when the patients were awake and at 2, 4, 6, 8, and 24 h after I.A. injection. Patients who complained of pain in the recovery room received increments of intravenous meperidine 25-50 mg. On discharge from the recovery room, patients received oral mefenamic acid 250-500 mg for pain relief. The time and quantity of analgesics required were recorded. Patients in Group 1 had significantly (P < 0.05) lower pain scores than those in Group 2 at 2, 4, 6, and 8 h postoperatively. These low pain scores were associated with lower requirements of supplementary analgesics. We conclude that, as compared with releasing the tourniquet immediately after I.A. injection of morphine, maintaining the tourniquet inflated for 10 min provides superior analgesia and decreases the need for supplemental analgesics.

Postoperative analgesia after lumbar laminectomy: epidural fentanyl infusion versus patient-controlled intravenous morphine.

We compared the efficacy and safety of continuous epidural fentanyl infusion with intravenous morphine via a patient-controlled analgesia system (IV-PCA) in the management of postoperative pain after lumbar laminectomy. Twenty patients undergoing elective lumbar laminectomy were randomly allocated to one of two groups. The epidural group (n = 10) received an epidural fentanyl infusion (2 micrograms/mL at 4-10 mL/h) while the IV-PCA group (n = 10) received IV morphine through a PCA system. The general anesthetic technique was standardized. Visual analog pain scores were recorded at 12, 24, and 48 h after the operation. The amount of morphine (or its equivalent in fentanyl) used over the 48-h postoperative period was documented. The postoperative pain scores were significantly lower in the epidural group than in the IV-PCA group throughout the study period. The total consumption of morphine (or its fentanyl equivalent) over the 48-h period was significantly lower (P < 0.001) in the epidural group compared to the IV-PCA group. Although more patients in the IV-PCA group required urinary catheterization and had somnolence than the epidural group, there was no difference in the incidence of vomiting or pruritus. No patient developed respiratory depression or wound infection. We conclude that continuous epidural infusion of fentanyl is superior to IV-PCA morphine in the management of pain after lumbar laminectomy.

Evaluation of combined spinal-epidural anesthesia using two different techniques.

BACKGROUND AND OBJECTIVES: This investigation was designed to evaluate combined spinal-epidural anesthesia with a needle-through-needle technique using two different needle sets. One kit has a standard 16-gauge Tuohy needle and a 26-gauge spinal needle that extends 13 mm beyond the tip of the Tuohy needle (set A). The other kit consists of a 16-gauge Tuohy needle with an aperture in its curve (back hole) for the insertion of a 26-gauge spinal needle that protrudes 10 mm beyond the tip of the epidural needle (set B). METHODS: Combined spinal-epidural anesthesia was used in 40 consecutive consenting patients scheduled for elective total knee arthroplasty who were randomized into two groups. Needle set A was used in group A, and needle set B was used in group B. Special attention was paid to difficulties in performing the blocks and to any complications of the technique. RESULTS: The length of the spinal needle was inadequate in 15% of patients from group B, whereas the length in group A was adequate in all. The aperture on the back of the Tuohy needle from group B provides a better "feel" of dural puncture. There was no difficulty in the insertion of the epidural catheter. There was no evidence of subarachnoid placement of the epidural catheter in either group. None of the patients had unexpectedly extensive spinal block. No patient developed postdural puncture headache. All patients had adequate surgical anesthesia. Infusion of bupivacaine (0.1%) with fentanyl (2 micrograms/mL) provided adequate postoperative analgesia. No respiratory depression was noted. CONCLUSIONS: Combined spinal-epidural provides satisfactory surgical and postoperative analgesia for total knee arthroplasty. An improved needle set for the needle-through-needle technique would be one with a modified Tuohy needle having an aperture at the back and a spinal needle protruding more than 13 mm beyond the Tuohy needle.

Effects of intraarticular morphine on analgesic requirements after anterior cruciate ligament repair.

BACKGROUND AND OBJECTIVES: Intraarticular morphine has been shown to provide postoperative pain relief after knee arthroscopy. The analgesia results from local action within the knee joint. This study was conducted to assess the efficacy of intraarticular morphine as a treatment for postoperative pain after anterior cruciate ligament repair. METHODS: A randomized double blind-study was conducted in patients undergoing elective anterior cruciate ligament repair. Patients in the study group (n = 10) received intraarticularly 5 mg of morphine in a 25 ml dilution. Those in the control group (n = 10) received 25 ml of saline by the same route. Intravenous morphine with patient-controlled analgesia was used in the postoperative period in both the groups. Visual analog scores were recorded at 1, 2, 4, 8, and 24 hours after the operation. The amount of morphine used over the 24-hour postoperative period was documented. RESULTS: The total consumption of morphine over the 24-hour period was significantly lower (p < 0.01) in the study group compared to the control group. The postoperative pain scores were lower in the study group throughout the study period, but this did not reach statistical significance. CONCLUSIONS: Intraarticular morphine reduces analgesic requirements after anterior cruciate ligament repair and is an effective method of providing postoperative analgesia.

Analgesia following arthroscopic knee surgery. A controlled study of intra-articular morphine, bupivacaine or both combined.

In a double-blind, randomised controlled trial, we studied 40 patients who received one of four intra-articular injections at the end of arthroscopic surgery. Each group contained ten patients. The patients in Group 1 received normal saline 25 ml; those in Group 2 received bupivacaine 0.25% 25 ml; those in Group 3 received morphine 5 mg in normal saline 25 ml; and those in Group 4 received a combination of bupivacaine 0.5% 12.5 ml and 5 mg of morphine made up to 25 ml with normal saline to produce the same bupivacaine concentration as Group 2. At the time the patient awoke, and 30min, 1hr, 1hr 30min, 2hr, 4hr, 8hr, 12hr, and 24hr postoperatively, pain was assessed using a visual analogue scale. The need for supplementary analgesic agents in the first 24 hours was recorded. All pain scores were significantly lower (P < 0.05) in Groups 2, 3 and 4 compared with the control group with the exception of Group 2 at 24 hours. Pain scores were significantly lower (P < 0.05) for Group 2 compared with Group 3 for the first 90 minutes postoperatively. At 4, 8, 12 and 24 hours postoperatively the pain scores were significantly lower (P < 0.05%) for Group 3 compared with Group 2. Group 4 had the lowest pain scores over the recorded period compared with the other groups. The need for supplemental analgesia was significantly lower (P < 0.05) in the treatment Groups 2, 3 and 4 compared to the control Group 1. There was no significant difference in supplemental analgesic requirements between Groups 2, 3 and 4.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood transfusion in total hip arthroplasty: guidelines to eliminate overtransfusion.

This study was designed to evaluate the effect of transfusion guidelines on perioperative blood usage with a view to identifying a protocol for transfusion therapy in our hospital. Eighty consecutive patients with normal haemoglobin concentrations presenting for total hip arthroplasty were studied. The maximum allowable blood loss (MABL) was calculated for each patient using the formula of Kallos et al. Blood loss up to this value was replaced with Haemaccel. When the MABL was reached, a haematocrit (Hct) was performed and blood was given if the Hct was less than 30 in men and 27 in women. Otherwise replacement was with Haemaccel. All postoperative complications, duration of hospital stay, and physiotherapy compliance assessments were recorded. A discharge Hct > 36% was the criterion for overtransfusion. The results were compared with findings from a retrospective group before the introduction of these guidelines. Analysis of the data demonstrated a reduction in the frequency of transfusion (97% vs 32% P < 0.05), the volume transfused (2.7 vs 1.3 units P < 0.05), and the incidence of overtransfusion (45% vs 5% P < 0.05) between the two groups of patients. There was no difference between the groups in complication rate, duration of hospital stay or physiotherapy scoring. We conclude that the introduction of guidelines for transfusion in total hip arthroplasty patients has produced a marked reduction in blood usage in our hospital without detrimental effect.

Intraarticular analgesia following knee arthroscopy.

A randomized, double-blind, controlled study was conducted in patients undergoing elective knee arthroscopy to assess the analgesic effect of intraarticular morphine and bupivacaine, alone and in combination. Patients in group 1 (n = 10) received 5 mg of morphine in 25 mL of saline; patients in group 2 (n = 10) received 25 mL of 0.25% bupivacaine (62.5 mg); patients in group 3 (n = 10) received a combination of 5 mg of morphine and 62.5 mg of bupivacaine in 25 mL dilution; and patients in group 4 (n = 10) received 25 mL of saline. All the drugs were injected intraarticularly. Postoperative pain was assessed using the visual analogue scale at 1, 2, 4, 8, and 24 h after the intraarticular injection. The need for supplemental analgesia was recorded. Results showed that there was no significant difference in the pain scores or analgesic requirements between groups 1 and 3. Patients in groups 1 and 3 had significantly lower pain scores than those in groups 2 and 4. These low pain scores were associated with lower requirements of supplementary analgesics. The patients in group 4 showed the highest pain scores and analgesic requirements. We conclude that intraarticular morphine significantly reduces postoperative pain following knee arthroscopy and that there is no advantage of combining bupivacaine with morphine.

Intra-articular morphine for pain relief after anterior cruciate ligament repair.

We have performed a randomized, double-blind controlled study in patients undergoing elective anterior cruciate ligament repair, to assess the effect of intra-articular morphine on postoperative pain. The morphine group (n = 11) received morphine 5 mg in saline 25 ml and the control group (n = 9), saline 25 ml intra-articularly. Patients in the morphine group had significantly smaller pain scores throughout the 24-h postoperative period compared with those in the control group (P < 0.05). There was less requirement for supplementary analgesics in the morphine group.

Intra-articular morphine for pain relief after knee arthroscopy.

We performed a randomised double-blind controlled study in patients undergoing elective knee arthroscopy to assess the effect of intra-articular morphine on postoperative pain relief. Patients in the study group (n = 10) received 5 mg of morphine in a 25 ml dilution intra-articularly while those in the control group (n = 10) received 25 ml of saline. Postoperative pain was assessed at intervals by a visual analogue scale and the requirement for supplementary analgesia was recorded. Those in the study group had significantly lower pain scores and required less systemic analgesics than those in the control group. Plasma profiles for morphine and its metabolites were assayed and showed that they were too low to produce effective analgesia. Evidence suggests that analgesia was mediated by local action within the joint.

Effects of three anesthetic induction techniques on heart rate variability.

STUDY OBJECTIVE: To investigate the effects of different clinical induction techniques on heart rate variability (HRV). DESIGN: Two studies are reported. Study 1 prospectively compared the effects of two induction techniques (etomidate vs. thiopental sodium) known to have widely disparate effects on cardiovascular reflexes. Study 2 specifically investigated whether the vagotonic effects of sufentanil cause an increase in vagally mediated HRV. SETTING: Elective surgery in a university-affiliated hospital. PATIENTS: Study 1: 18 ASA physical status I patients having minor surgery; Study 2: 10 ASA physical status III and IV patients having cardiac surgery. INTERVENTIONS: In Study 1, anesthesia was induced with either etomidate 0.3 mg/kg or thiopental sodium 4 mg/kg with 60% nitrous oxide in oxygen. In Study 2, anesthesia was induced with a sufentanil infusion (total dose 2.9 +/- 0.2 micrograms/kg). MEASUREMENTS AND MAIN RESULTS: The electrocardiogram-derived heart rate signal was subjected to power spectral analysis (similar to electroencephalographic analysis) to obtain measurements of (1) absolute HRV power [units of (beats per minute)2] within defined frequency ranges (HRVLO = power between 0 and 0.125 Hz; HRVHI = power between 0.126 and 0.5 Hz; HRVTOT = HRVLO + HRVHI) and (2) normalized HRV power (the percentage of total power) within these same frequency ranges [e.g., %HRVHI = (HRVHI/HRVTOT) x 100%]. In Study 1, both techniques caused large reductions in HRVTOT. The reduction caused by the thiopental sodium technique (-89% +/- 2%) significantly exceeded that caused by the etomidate technique (-58% +/- 13%, p less than 0.02). In Study 2, sufentanil decreased absolute power measurements of vagally mediated HRV (-69 +/- 12 change in HRVHI) but increased corresponding normalized measurements of vagally mediated HRV (90% +/- 30% increase in %HRVHI). CONCLUSIONS: In Study 1, the greater reduction in HRV with the thiopental sodium technique provides evidence that the depressant effects of anesthetics on HRV are related in part to their effects on cardiovascular reflexes. However, the significant depression in HRV caused by the etomidate technique suggests that mechanisms other than baroreflex depression (e.g., impaired consciousness) also are important in these depressant effects. In Study 2, the decrease in HRVHI caused by sufentanil documents that absolute power measurements of vagally mediated HRV are not correlated with changes in parasympathetic tone during a potent opioid induction. This lack of a correlation may result from the decrease in total HRV observed with loss of consciousness. The increase in %HRVHI suggests that normalized measurements of HRV may still provide an index of changes in sympathetic-parasympathetic balance, even when total HRV is decreased following anesthetic administration.

Transfusion therapy in elective total hip arthroplasty.

A retrospective audit of transfusion practice in 150 consecutive elective primary total hip arthroplasties was undertaken, to examine blood usage and to determine the potential for reduction in its use. Predetermined criteria were used to measure unnecessary transfusions. Transfusion was considered unnecessary if the discharge haematocrit exceeded 36%, or if patients who lost less than 30% of their estimated blood volume, were transfused. Using these criteria, overtransfusion occurred in 42-45% patients. The intra-operative blood transfused correlated well with intra-operative blood lost. All other variables showed no significant correlation with both intra-operative and post-operative blood transfused. Females lost less and were transfused significantly more than males. The study corroborates previous reports of blood overuse. These results suggest that adopting standards of practice to measure and to monitor transfusion practice (quality assurance programmes) would be a worthwhile objective.

Dose-response curves for edrophonium, neostigmine, and pyridostigmine after pancuronium and d-tubocurarine.

To determine the potencies of neostigmine, pyridostigmine, and edrophonium in reversing pancuronium and d-tubocurarine blockade, dose-response curves were established for first twitch height recovery and train-of-four ratio. One hundred and twenty ASA physical status I or II patients scheduled for elective surgery received either 0.06 mg/kg pancuronium or 0.36 mg/kg d-tubocurarine during a thiopental-nitrous oxide-enflurane anesthetic. Train-of-four stimulation was applied every 12 s, and the force of contraction of the adductor pollicis muscle was recorded. When first twitch height had recovered spontaneously to 10% of its initial value, neostigmine (0.005, 0.01, 0.02 or 0.05 mg/kg), pyridostigmine (0.02, 0.04, 0.1, or 0.2 mg/kg), or edrophonium (0.1, 0.2, 0.4 or 1 mg/kg) was injected by random allocation. Recovery was measured 10 min after the injection of the antagonist. First twitch ED50's were 0.013, 0.085, and 0.17 mg/kg after pancuronium, and 0.017, 0.11, and 0.27 mg/kg after d-tubocurarine, for neostigmine, pyridostigmine, and edrophonium, respectively. The ED50 for pyridostigmine and edrophonium obtained after d-tubocurarine was significantly larger (P less than 0.05) than that after pancuronium. The train-of-four dose-response curves were significantly flatter for edrophonium than for the other two agents, indicating a greater ability of edrophonium to antagonize fade at low doses. It is concluded that the potency of reversal agents may be different for different relaxants, and that potency ratios might depend upon the end-point chosen as full neuromuscular recovery.