Local infiltration analgesia with levobupivacaine compared with intrathecal morphine in total hip arthroplasty patients.

BACKGROUND: Recently, local infiltration analgesia (LIA) has been promoted for pain control after total hip arthroplasty (THA). We hypothesized that LIA would offer equal analgesic efficacy but less adverse effects, e.g., nausea and vomiting, when compared with an established regimen [intrathecal morphine (it-M)] after THA. METHODS: This randomized controlled trial comprised 60 patients undergoing THA under spinal anaesthesia. For LIA, the surgeon administered levobupivacaine, ketorolac and epinephrine at the surgical site intraoperatively. LIA patients received a LIA top-up through a wound catheter on the morning of the 1st post-operative day (POD). In group it-M, 0.1 mg morphine was given together with the spinal anaesthetic. Study parameters included pain scores, vital parameters and side effects, e.g., post-operative nausea and vomiting (PONV). Besides, levobupivacaine plasma concentrations were determined in 10 LIA patients. RESULTS: The median (25th/75th percentiles) rescue oxycodone demand differed significantly with LIA 15 (10/25) mg vs. 8.5 (1.5/15) mg with it-M (P < 0.006) during the day of surgery, but not anymore on 1st or 2nd POD. The LIA top-up had no effect. However, both analgesic regimens resulted in comparable pain scores and patient satisfaction. PONV incidence and medication did not vary significantly. LIA offered certain advantages regarding early post-operative mobilization. Maximum levobupivacaine plasma concentrations (229-580 ng/ml) remained under the toxic level. CONCLUSIONS: While LIA might enable earlier mobilization after THA, it was not associated with less nausea as compared with it-M. Less rescue oxycodone was given early after it-M, but urinary retention was more common in that group.

The analgesic effect of continuous subacromial bupivacaine infusion after arthroscopic shoulder surgery: a randomized controlled trial.

BACKGROUND: The benefits of subacromial local anesthetic infusion are controversial. The aim of this study was to evaluate the efficacy of subacromial bupivacaine infusion after arthroscopic acromionplasty and rotator cuff procedures. METHODS: Ninety patients with subacromial impingement disease scheduled for elective shoulder arthroscopy were enrolled in this randomized, prospective and placebo-controlled study. The patients received subacromially either 5.0 mg/ml bupivacaine or 9.0 mg/ml saline at the rate of 2 ml/h post-operatively for 48 h. The primary outcome measure was the use of rescue oxycodone. The consumption of opioids, ibuprofen, paracetamol and codeine, and the intensity of pain were recorded. RESULTS: Patients receiving bupivacaine infusion used significantly less oxycodone compared with patients receiving saline [15 vs. 20 mg (median) oxycodone intravenously on the day of surgery, 0 vs. 10 mg (median) perorally on the first post-operative day]. There was no significant difference in the use of ibuprofen, paracetamol and codeine, except that paracetamol was used more in patients receiving saline during the day of surgery (P = 0.009). The pain scores of patients receiving bupivacaine were lower at 18 h (P = 0.008). Average pain scores for the worst pain experienced did not differ between the groups. There were three (4%) premature discontinuations because of technical problems. CONCLUSIONS: Considering the low need of opioids, expenses and technical problems in these patients, subacromial 5.0 mg/ml bupivacaine infusion 2 ml/h confers only moderate and probably clinically insignificant efficacy compared with placebo. This efficacy might be overweighed by the disadvantages.

Comparison of four pain scales in patients with hip fracture or other lower limb trauma.

BACKGROUND: The applicability of the Visual Analogue Scale (VAS) has been questioned in the assessment of pain in the elderly. We compared VAS with three other pain scales, Verbal Rating Scale (VRS), Red Wedge Scale (RWS) and Box Scale (BS), in hip fracture patients. METHODS: VAS, VRS, RWS and BS were compared in 140 analysable patients undergoing surgery, 70 with hip fracture and 70 with other lower limb trauma. Pain scores were recorded once a day, repeated after 10 min, for 4 subsequent days starting pre-operatively. The primary endpoint was the rate of successful pain measurements in hip fracture patients and 90% was chosen as a sufficient level for an applicable pain scale. RESULTS: Age was different between the groups (hip fracture 78 ± 11, other trauma 49 ± 11 years, P<0.0001). In hip fracture patients, 67-83% of pain measurements were successful with VAS, 82-100% with VRS, 83-96% with RWS and 79-91% with BS. The success rate with VAS was significantly <90% on 2 days (P<0.0001) and with BS on 1 day (P=0.04). All the other success rates with the four scales in both groups were above or not different from 90%. CONCLUSION: VRS and RWS were the most applicable scales, unlike VAS, which appeared to be an unreliable pain scale in perioperative hip fracture patients. In patients with other lower limb trauma, all four scales provided excellent applicability. Our results are in accordance with the accumulating evidence suggesting that VAS is not an ideal tool for pain measurement in the elderly.

Plasma levels of bupivacaine and its metabolites after subacromial infusions in concentrations 2.5 or 5.0 mg/ml.

BACKGROUND: We studied plasma bupivacaine concentrations in patients with a continuous subacromial bupivacaine infusion after an ambulatory arthroscopic shoulder surgery to evaluate whether it is feasible to discharge patients with an on-going infusion early on the operation day. METHODS: Sixteen ASA I-III patients undergoing elective arthroscopic shoulder surgery were randomized in 1:1 ratio to receive a continuous infusion of either 2.5 or 5.0 mg/ml bupivacaine subacromially for 48 h post-operatively. Before the commencement of the infusion, 20 ml of 5.0 mg/ml bupivacaine was injected subacromially in both groups. Plasma bupivacaine concentrations were defined as the primary endpoint and concentrations of its metabolites, side effects and pain scores as the secondary endpoints. RESULTS: The mean total plasma bupivacaine concentration increased up to 48 h, the highest mean being 0.87 (SD 0.30) µg/ml during the 5.0 mg/ml treatment and 0.24 (0.10) µg/ml during the 2.5 mg/ml bupivacaine treatment. After 48 h, there was a significant difference between the groups in the plasma levels. The highest mean 4-hydroxy-bupivacaine and desbutylbupivacaine concentrations were 0.11 and 0.22 µg/ml, respectively. In the pain scores, no significant difference was found. No clear signs of toxicity were observed. CONCLUSIONS: The concentrations of total bupivacaine and its metabolites remained below toxic levels. Excluding patients with renal or liver diseases, both 2.5 and 5.0 mg/ml bupivacaine as subacromial infusion 2 ml/h for 48 h following shoulder arthroscopy seem to be well tolerated, enabling patient discharge with an on-going infusion on the operation day. Because of similar side effects and pain scores in both groups, 2.5 mg/ml may be preferable.

The effect of desmopressin on blood loss in patients with rheumatoid arthritis undergoing hip arthroplasty.

BACKGROUND: Blood loss is an important issue for patients with rheumatoid arthritis undergoing hip surgery. We hypothesised that intraoperative desmopressin treatment would result in a reduction in blood loss in rheumatoid patients undergoing total hip arthroplasty. METHODS: Seventy-five patients scheduled for elective total hip arthroplasty were randomised to three groups to receive 0.4 microg/kg desmopressin (D 0.4), 0.2 microg/kg desmopressin (D 0.2) or placebo intraoperatively in a double-blind fashion. Blood transfusions were based on calculated safe allowable blood loss and haemoglobin measurements (trigger 90 g/l, 5.59 mmol/l). The primary endpoint was the total blood loss measured till the end of the fourth post-operative day. Secondary endpoints included red cell transfusion requirements and haemoglobin. RESULTS: Total blood loss during the study period was not significantly different between the groups (D 0.4 1829 +/- 1068; D 0.2 2240 +/- 843 and placebo 2254 +/- 1040 ml; P= 0.50). The total amount of red cell transfusions was fewer in group D 0.4 (3.6 +/- 1.6 U) when compared with D 0.2 (4.4 +/- 1.7 U; P=0.009) and placebo (4.5 +/- 2.0 U; P= 0.011) groups. Haemoglobin concentration was lower in the placebo group in the first (5.42 +/- 1.16 vs. 5.98 +/- 0.47 mmol/l; P=0.033) and the second (6.28 +/- 0.66 vs. 6.69 +/- 0.47 mmol/l; P=0.033) post-operative mornings compared with group D 0.4. CONCLUSION: Despite a lack of difference in the primary outcome, total blood loss, intraoperative administration of 0.4 microg/kg desmopressin resulted in fewer total red cell transfusion requirements in rheumatoid patients undergoing total hip arthroplasty when compared with 0.2 microg/kg treatment and placebo.

Spread of spinal block in patients with rheumatoid arthritis.

BACKGROUND: In clinical practice, we noticed a greater than expected spread of sensory spinal block in patients with rheumatoid arthritis. We decided to test this impression and compared the spread of standard spinal anaesthesia in rheumatoid and non-rheumatoid control patients. METHODS: Spinal anaesthesia with 3.4 ml (17 mg) of plain bupivacaine was administered to 50 patients with seropositive rheumatioid arthritis and to 50 non-rheumatoid control patients. The protocol was standardised for all patients. All the patients were undergoing lower limb surgery and the rheumatoid patients were operated on due to their rheumatoid disease. The spread of sensory block was recorded 30 min from the dural puncture using a pin prick test and a cold ice-filled container. The impact of body mass index (BMI), height and age on the spread were analysed. RESULTS: The spread of sensory block was greater in patients with rheumatoid arthritis (15.6+/-3.1 dermatomes) than in non-rheumatoid patients (14.1+/-3.3 dermatomes) (P<0.05). Increasing BMI was related to cephalad spread of block in the rheumatoid group (P<0.05), but not in the control group. CONCLUSION: The mean spread of sensory block 30 min after the injection of plain bupivacaine was 1.5 segments cephalad in patients with rheumatoid arthritis than in those without this disease. BMI might be a patient-related factor contributing to the extent of the block in rheumatoid patients. These findings should be considered when performing a spinal block in rheumatoid patients.

The validity of the static-charge-sensitive bed in the detection of fentanyl-induced respiratory depression.

BACKGROUND: Only a few methods for the measurement of breathing are non-invasive and do not interfere with measured parameters. The static-charge-sensitive bed (SCSB) could be such a monitor. The aim of this study was to evaluate the validity of the SCSB compared with the respiratory inductive plethysmograph (RIP) using a fentanyl-induced respiratory depression model. METHODS: Eight healthy male volunteers were infused with intravenous (i.v.) fentanyl (15 microg/kg/h) until a decrease in SpO2 below 90% for 1 min emerged. Breathing was continuously and simultaneously measured with SCSB and RIP. Oxygenation, hemodynamics, arterial blood gas analysis, and subjective opioid-related effects were monitored. Fentanyl concentration was measured from an arterial blood sample. The respiratory rate data of the SCSB (automated analysis and manual calculation) were compared with the corresponding RIP data, using analysis of variance for repeated measures. The validity of the SCSB compared with RIP was evaluated using an intra-class correlation coefficient. RESULTS: Mean fentanyl dose was 629 microg. A statistically significant association was found between the RIP and SCSB data in the manual SCSB analysis (P < 0.0001), but not in the automated SCSB analysis (P = 0.91). After adjusting for the effect of time and the SCSB method, an intra-class correlation coefficient between the manually calculated SCSB values and the RIP values was 0.66. CONCLUSION: Clinically significant changes in respiratory rate were detected with the SCSB, but the results had to be analyzed manually. The SCSB best suits situations, where comprehensive data are needed. It is not suitable for on-line respiratory monitoring, as the automated analysis did not calculate the respiratory rate correctly.

Barbiturate anesthesia and brain proton spectroscopy.

BACKGROUND AND PURPOSE: Thiopentone reduces CBF and metabolic rate. Still, it is widely used for sedation during MR spectroscopy. We investigated whether barbiturate anesthesia and preanesthetic fasting have an effect on metabolic ratios in proton MR spectroscopy of the brain. METHODS: Eight healthy, consenting, male volunteers were studied twice in a random, crossover fashion. The study sessions were conducted during fasting (F) and nonfasting (nonF), with glucose infusion mimicking the fed state. During both sessions, two sets of spectroscopic data were collected, one during the awake state (F or nonF) and one under barbiturate anesthesia (F+B or nonF+B), using TEs of 135 and 270. Spectral areas of N-acetylaspartate (NAA), choline-containing compounds (Cho), and creatine plus phosphocreatine (Cr) were calculated, and the presence of lactate or lipid was noted. Venous blood samples for glucose, beta-hydroxybutyrate, lactate, and electrolytes were collected. RESULTS: Barbiturate anesthesia caused a 42% reduction in blood lactate levels during fasting, but not during glucose infusion. There were no differences in NAA/Cho, NAA/Cr, or in Cho/Cr between the groups F, nonF, F+B, or nonF+B. No lactate or lipid resonances were detected. CONCLUSION: Barbiturate anesthesia with preanesthetic fasting can be used for proton spectroscopy at TEs of 135 or 270 without interference from NAA/Cho, NAA/Cr, or Cho/Cr or from the appearance of lactate or lipid.

Effects of tramadol and meperidine on respiration, plasma catecholamine concentrations, and hemodynamics.

STUDY OBJECTIVE: To evaluate the effects of high analgesic doses of tramadol and meperidine on respiration, plasma catecholamine concentrations, and hemodynamic parameters. STUDY DESIGN: Randomized, double-blind, cross-over, controlled volunteer study. SETTING: Laboratory at a university hospital. SUBJECTS: 8 healthy male volunteers. INTERVENTIONS: Tramadol was given as a 150 mg bolus plus a succeeding 3-hour steady infusion of 250 mg (83.3 mg/hr). Meperidine was given in a similar manner as a bolus dose of 112.5 mg plus 187.5 mg in a 3-hour steady infusion (62.5 mg/hr). Experimental pain was induced using a tourniquet. MEASUREMENTS AND MAIN RESULTS: Respiration was studied noninvasively with respiratory inductive plethysmography and pulse oximetry. Arterial line was used for measurement of hemodynamics and blood sampling. Tramadol did not have any clinically significant effects on respiration, breathing pattern, or hemodynamics, but an increase in plasma epinephrine levels was noted. Meperidine bolus decreased tidal volume (p < 0.05, difference from baseline) and pulse oxygen saturation (from 97% to 94%, p < 0.05), but during the succeeding infusion, the respiratory drive, measured as mean inspiratory flow, was enhanced (p < 0.05 difference from baseline), and the respiratory parameters returned to baseline level. No change in hemodynamics was noted, but a significant increase in plasma norepinephrine and epinephrine levels (from 0.9 to 1.6 nmol/L and from 0.3 to 0.8 nmol/L, respectively; p < 0.05) was observed after meperidine administration. Tramadol caused nausea more often than meperidine (p < 0.05, between treatments). CONCLUSIONS: Tramadol exhibited a minimal effect on respiration and breathing pattern in healthy volunteers. The respiratory effects of meperidine bolus were predictable with decreasing tidal volume and pulse oxygen saturation. In contrast, during meperidine infusion, adequate respiration was preserved despite the large amount of meperidine infused.