Effect of intravenous lipid emulsion on bupivacaine plasma concentration in humans.

Intravenous lipid emulsion is the recommended treatment for severe local anaesthetic intoxication. Lipid emulsion may entrap lipid soluble drugs by functioning as a 'lipid sink', but its effect on bupivacaine pharmacokinetics remains unknown. In this randomised, double-blind, crossover study, eight healthy male volunteers were infused bupivacaine 0.5mg.kg(-1) intravenously over 20 min, followed by an infusion of either intravenous lipid emulsion or Hartmann's solution for 30 min. At 20 and 30 min after the start of the infusion, the total plasma bupivacaine concentration was lower while receiving lipid emulsion than Hartmann's solution (mean difference 111 (95% CI 55-167) µg.l(-1) and 75 (95% CI 26-124 µg.l(-1) at 20 and 30 min, respectively; p<0.02). However, there were no differences in un-entrapped (non-lipid bound) or free (non-protein bound) bupivacaine plasma concentrations during the infusion. Intravenous lipid emulsion infusion reduced the context-sensitive half-life of total plasma bupivacaine from 45 (95% CI 32-76)min to 25 (95% CI 20-33)min; p=0.01. We observed no significant adverse effects of lipid emulsion. In conclusion, lipid emulsion may slightly increase the rate of bupivacaine tissue distribution. No 'lipid sink' effect was observed with the non-toxic dose of bupivacaine used.

Pregabalin has an opioid-sparing effect in elderly patients after cardiac surgery: a randomized placebo-controlled trial.

BACKGROUND: In this prospective, randomized, double-blind, placebo-controlled study, we investigated the effect of pregabalin on oxycodone consumption, postoperative confusion, and pain in elderly cardiac surgery patients. METHODS: Seventy patients, aged ≥75 yr, were randomized to receive either 150 mg of pregabalin before operation and 75 mg of pregabalin twice daily for 5 postoperative days or placebo. Pain intensity was measured with the Verbal Rating Scale (VRS). When pain intensity was ≥2 on the VRS, patients received oxycodone either i.v. (0.05 mg kg(-1)) or orally (0.10-0.15 mg kg(-1)). Postoperative confusion was measured with the Confusion Assessment Method for the intensive care unit (CAM-ICU). Postoperative pain was assessed by a telephone interview 1 and 3 months after operation. RESULTS: Cumulative consumption of parenteral oxycodone during 16 h after extubation was reduced by 44% and total oxycodone consumption from extubation to the end of the fifth postoperative day was reduced by 48% in the pregabalin group. Time to extubation was 138 min shorter and CAM-ICU scores were significantly lower on the first postoperative day in the placebo group, although there was no significant difference with respect to the Mini-Mental State Examination or the Richmond Agitation Sedation Score. The incidence of pain during movement was significantly lower in the pregabalin group at 3 months postoperative. CONCLUSIONS: The administration of pregabalin reduced postoperative opioid consumption after cardiac surgery reduced the incidence of confusion on the first postoperative day and increased time to extubation when compared with placebo. Three months after operation, patients in the pregabalin group experienced less pain during movement.

Evaluation of easily applicable pain measurement tools for the assessment of pain in demented patients.

BACKGROUND AND OBJECTIVES: Difficulties in communication and lack of suitable pain scales may lead to undertreatment of pain in cognitively impaired patients. We performed a study in this type of patients and evaluated the usefulness of four simple pain scales. PATIENTS AND METHODS: We studied 41 hospitalized elderly (76-95 years) who suffered from pain with an acute component. Cognitive function was assessed with the mini-mental state examination (MMSE) and the degree of depression was assessed on the geriatric depression scale (GDS). Pain intensity was assessed at rest and after a pain-provoking movement three times at 2-week intervals by repeating the test at a 10-min interval at each test session. The pain scales were the 50 cm red wedge scale (RWS), the seven-point faces pain scale (FPS), the 10 cm visual analogue scale (VAS) and the five-point verbal rating scale (VRS). RESULTS: In group MMSE> or =24, patients were able to use all four scales rather successfully. In the other groups (MMSE 17-23, 11-16 and < or =10), only the use of VRS was successful to a reasonable degree (64-85% on average). GDS scores did not correlate with the pain scores, with the exception of pain scores on FPS during movement (P<0.01). The estimations of intensity and frequency of pain performed by nurses failed to correlate with the patient's own pain intensity estimations. CONCLUSION: Scoring of pain with RWS, FPS and VAS seems to be feasible in elderly patients with a normal cognitive dysfunction. In our study VRS appeared to be applicable in the elderly with a clear cognitive dysfunction, i.e., with MMSE<17.

Comparison of effects and plasma concentrations of opioids between elderly and middle-aged patients after cardiac surgery.

BACKGROUND: In elderly patients, opioids may cause prominent postoperative sedation and respiratory depression. We evaluated the influence of age on the effects of opioids and plasma concentrations of fentanyl and oxycodone in cardiac surgery patients. METHODS: Thirty (>or=75 years, gender M9/F21) and 20 (

Applicability of tools to assess pain in elderly patients after cardiac surgery.

BACKGROUND: Post-operatively, elderly patients with impaired vision and cognitive dysfunction may experience difficulties understanding standard pain assessment tools such as the 10-cm Visual Analogue Scale (VAS) and the Verbal Rating Scale (VRS). Thus, there is a need to identify more feasible post-operative pain assessments for elderly patients. With this goal in mind, we compared the VAS and VRS with two more expressive tools: the 50-cm Red Wedge Scale (RWS) and the Facial Pain Scale (FPS). METHODS: Cardiac surgery patients (73 +/- 5 years, mean +/- SD) were allocated to an RWS (n=80) or an FPS (n=80) group. Pain was assessed at rest and after movement during the first 4 days after tracheal extubation. The RWS or FPS assessments were repeated after 10 min. All patients completed the VRS and VAS. RESULTS: The rates of successful pain measurement on study day 1 were: VRS 86%, VAS 62%, RWS 78%, and FPS 60%. Pain measurements with the RWS correlated with the VAS (r=0.758, P<0.001) and weaker with the VRS (r=0.666, P<0.001) measurements. Pain measurements with the FPS correlated well with the VAS (r=0.873, P<0.001) and weaker with the VRS (r=0.583, P<0.001) measurements. With all scales, success rates improved during the study period. CONCLUSION: In elderly patients, immediately after cardiac surgery, the VRS is the most feasible pain scale, followed by the RWS. The traditional 10-cm VAS is unsuitable for pain measurement in this population.

Propacetamol and diclofenac alone and in combination for analgesia after elective tonsillectomy.

BACKGROUND: Diclofenac and paracetamol have different mechanisms and sites of action. Therefore, we tested if their combination is more effective for analgesia after tonsillectomy than either drug alone with respect to rescue analgesic consumption and visual analog scale values. METHODS: The analgesic effects of intravenously administered propacetamol (injectable pro-drug of paracetamol) and diclofenac or a combination on postoperative pain were compared in 71 adult elective tonsillectomy patients in a randomized, double-blind study. After induction of anesthesia the patients received monotherapy with 2 g propacetamol (n = 25) or 75 mg diclofenac (n = 25), or a combined treatment with 2 g propacetamol and 75 mg diclofenac (n = 21) in physiologic saline as an infusion. Postoperatively the propacetamol dosage was repeated twice and diclofenac once on the ward. Oxycodone (0.03 mg kg(-1)) was used as a rescue analgesic by patient-controlled analgesia. RESULTS: On average the patients needed oxycodone 15.3, 13.2 and 10.6 times in the propacetamol, diclofenac and combination groups, respectively (NS). A verbal rating scale and a visual analog scale were employed for assessing post-tonsillectomy pain, nausea and patient satisfaction in all groups. No statistically significant differences were found between the groups. Twelve of the 25 (48%) patients having received propacetamol complained of pain at the cannulation site. CONCLUSION: Combined treatment with propacetamol and diclofenac with the dosages used provided clinically only a minor advantage over monotherapy with propacetamol or diclofenac with respect to postoperative analgesia or the incidence of side-effects in adult tonsillectomy patients.

Comparison of remifentanil versus ketamine for paediatric day case adenoidectomy.

Few studies exist of using remifentanil and intravenous ketamine for anaesthetic induction in paediatric day case anaesthesia. Therefore, we studied 75 unpremedicated ASA I-II children (age 1-7 years) who were randomly assigned in a double-blind fashion to receive either remifentanil (1 microgram/kg), ketamine (0.7 mg/kg) or placebo before the anaesthetic induction. Anaesthesia was induced with propofol and maintained with O2-N2O-sevoflurane. Induction characteristics, recovery times and the need for postoperative analgesia were evaluated. The required induction dose of propofol was lower in the groups receiving remifentanil and ketamine compared with the group receiving placebo. After tracheal intubation heart rate and blood pressure were better attenuated with remifentanil than with ketamine or placebo. In the recovery room children in the placebo group required more doses of oxycodone than the other two groups but this did not reach statistical significance. There were no differences between the groups in achieving predetermined recovery end-points, attaining full points on the Steward score or in the well being at home. In conclusion, remifentanil provides haemodynamically more stable induction of anaesthesia compared with ketamine or placebo. Ketamine with its' longer duration of action does not prolong recovery but does not have a clear opioid-sparing effect either in the immediate postoperative period.

Confirmation of caudal needle placement using nerve stimulation.

BACKGROUND: The study was designed to examine a new method of confirming proper caudal needle placement using nerve stimulation. METHODS: Thirty-two pediatric patients were studied. A 22-gauge insulated needle was inserted into the caudal canal via the sacral notch until a "pop" was felt. The needle placement was classified as correct or incorrect depending upon the presence or absence of anal sphincter contraction (S2-S4) to electrical simulation (1 to 10 mA). RESULTS: Three patients were excluded, two because they inadvertently received neuromuscular blockers and one because the patient's anatomy precluded any attempt at a caudal block. The sensitivity and specificity of the test were both 100% in predicting clinical outcomes of the caudal block. Six patients had a negative stimulation test after the first attempt to place the needle. Four of these went on to receive a second attempt of needle insertion after a subcutaneous bulge or resistance to local anesthetic injection were observed. Following needle reinsertion, positive stimulation tests were elicited. These patients received the local anesthetic injection with ease and had good analgesia postoperatively. No attempt was made to reinsert the needle in the remaining two patients with a negative stimulation test, as they did not show subcutaneous bulge or resistance upon injection. These patients had poor analgesia postoperatively. The positive predictive value of the test was greater than the presence of a "pop" alone (P < 0.05) but not significantly different (P = 0.492) over the presence of "pop" and easy injection. CONCLUSION: This test may be used as a teaching and adjuvant tool in performing caudal block.

Premedication with midazolam delays recovery after ambulatory sevoflurane anesthesia in children.

UNLABELLED: We studied the effect of oral premedication with midazolam on the recovery characteristics of sevoflurane anesthesia in small children. In a randomized, double-blinded study, 60 children (1-3 yr, ASA physical status I or II) undergoing ambulatory adenoidectomy received either midazolam 0.5 mg/kg (Group M) or placebo (Group P) PO approximately 30 min before the induction of anesthesia. All children received atropine 0.01 mg/kg IV and alfentanil 10 microg/kg IV before the induction of anesthesia with sevoflurane up to 8 vol% inspired concentration in N2O 67% in O2. Tracheal intubation was facilitated with mivacurium 0.2 mg/kg. Anesthesia was continued with sevoflurane adjusted to maintain hemodynamic stability. In the postanesthesia care unit, predetermined recovery end points (emergence, recovery, discharge) were recorded. A pain/ discomfort scale was used to determine the quality of recovery. A postoperative questionnaire was used to evaluate the well-being of the patient at home 24 h after surgery. Emergence (spontaneous eye opening), recovery (full points on the modified Aldrete scale), and discharge were achieved later in Group M than in Group P (15+/-6 vs. 11+/-3 min [P = 0.002], 25+/-17 vs. 16+/-6 min [P = 0.01], and 80+/-23 vs. 70+/-23 min [P = 0.03]). Side effects, postanesthetic excitement, and analgesic treatment did not differ significantly between groups. At home, more children in Group P (30%) experienced disturbed sleep during the night compared with those in Group M (4%) (P = 0.007). IMPLICATIONS: In this randomized, double-blinded, placebo-controlled study, premedication with midazolam 0.5 mg/kg PO delayed recovery in children 1-3 yr of age after brief (<30 min) sevoflurane anesthesia. Except for more peaceful sleep at home, premedication did not affect the quality of recovery.

Ketoprofen, diclofenac or ketorolac for pain after tonsillectomy in adults?

We have compared the analgesic and opioid sparing effect of three i.v. non-steroidal anti-inflammatory drugs with placebo in a randomized, double-blind, placebo-controlled study in 80 adult patients after elective tonsillectomy. A standard anaesthetic was used. After induction of anaesthesia, patients received ketoprofen 100 mg, diclofenac 75 mg or ketorolac 30 mg by i.v. infusion over 30 min. Patients in the placebo group received saline. Ketoprofen and diclofenac infusions were repeated after 12 h and ketorolac infusion at 6 h and 12 h. Oxycodone was used as rescue analgesic. Patients in the ketoprofen group requested 32% less opioid and patients in the diclofenac and ketorolac groups 42% less opioid than those in the placebo group (P < 0.05). There were one, two and six patients in the placebo, diclofenac and ketorolac groups, respectively, but none in the ketoprofen group, who did not request opioid analgesia during the study (P < 0.05, ketorolac vs placebo and ketoprofen). Visual analogue pain scores were similar in all groups. Visual analogue satisfaction scores were significantly higher in the diclofenac group compared with the placebo group. The incidence of nausea was 44-54%. There were no differences in the incidence of other adverse reactions. We conclude that all three non-steroidal anti-inflammatory drugs were superior to placebo after tonsillectomy.

Sevoflurane-maintained anesthesia induced with propofol or sevoflurane in small children: induction and recovery characteristics.

PURPOSE: To compare the induction and recovery characteristics of sevoflurane anesthesia induced with either propofol or sevoflurane in pediatric outpatients. METHODS: Fifty-two children, aged 1-3 yr, presenting for ambulatory adenoidectomy were randomly allocated to receive 3 mg.kg-1 propofol i.v. or sevoflurane 8% inspired concentration for induction of anesthesia. Tracheal intubation was facilitated with 0.2 mg.kg-1 mivacurium. Anesthesia was maintained with nitrous oxide/oxygen (FiO2 0.3) and sevoflurane approximately 3-5% inspired concentration with controlled ventilation. Intubation was assessed by an anesthetist blinded to the induction method. Recovery characteristics were compared using the modified Aldrete scoring system, the Pain/Discomfort scale and measuring specific recovery times. A postoperative questionnaire was used to evaluate the children's well-being at home. RESULTS: Intubating conditions were similar in both groups. Emergence from anesthesia occurred earlier with sevoflurane for induction than with propofol (11 +/- 4 vs 17 +/- 7 min (mean +/- SD), P = 0.0002). More children in the sevoflurane group achieved full points on the modified Aldrete scoring system during the first 20 min after anesthesia (P < 0.05). However, children in the sevoflurane group scored higher in the Pain/Discomfort scale at 10 min after anesthesia (P = 0.04) and were given postoperative analgesics earlier than children in the propofol group (13 +/- 5 min vs 18 +/- 11 min, P = 0.03). The time to meet discharge criteria and recovery at home were similar. CONCLUSIONS: Induction of sevoflurane anesthesia with propofol for day-case adenoidectomy results in longer, but more calm, early recovery but does not delay discharge or affect recovery at home.

Efficacy and side effects of tramadol versus oxycodone for patient-controlled analgesia after maxillofacial surgery.

Tramadol, a weak opioid mu-receptor agonist, may have a favourable potency and side effect profile for intravenous patient-controlled analgesia (PCA). In a prospective, double-blind, randomized study involving 54 patients, tramadol was compared with oxycodone in PCA after maxillofacial surgery. All the patients were given diclofenac sodium 1 mg kg-1 intramuscularly and dexamethasone 8 mg twice a day. Post-operatively patients received tramadol or oxycodone by a PCA apparatus (lockout 5 min, tramadol 0.3 mg kg-1 bolus, oxycodone 0.03 mg kg-1 bolus). During the immediate recovery period, opioid was administered i.v. in a double-blind fashion, either tramadol 10 mg or oxycodone 1 mg increments until the pain control was judged to be satisfactory by the patient. Pain was assessed at rest and during activity (mouth opening) before and after loading, at 2 h after commencing the PCA, as well as at 21.00 and at 09.00 hours on the following morning. Side effects were recorded. The potency ratio of tramadol to oxycodone was found to be approximately 8:1. There was no significant difference between the groups in the VAS scores for pain. No respiratory depression was identified. Tramadol was found to provide adequate analgesia after maxillofacial surgery without risk of respiratory depression. However, the incidence of nausea was slightly greater in the tramadol group than in the oxycodone group (44% vs. 28%, NS).

Controlled release gel of ibuprofen and lidocaine in epidural use--analgesia and systemic absorption in pigs.

PURPOSE: Reduction of the frequency of injections and localization of the absorption of drug molecules to the injection site would be of great advantage in epidural pain treatment. The epidural use of a controlled release gel of lidocaine and ibuprofen was studied. METHODS: The effect of a poloxamer gel (25%) containing 2% lidocaine.HCl and 2% ibuprofen.Na on the duration of analgesia after epidural administration to pigs was compared with drug in solution. Analgesia was assessed by observing the motor function and the nociceptive reflex-withdrawal response to painful pressure stimulation on the feet. Pharmacokinetic and histological examinations were performed. RESULTS: Analgesia lasted significantly longer after epidural lidocaine gel injection in comparison with the solution. The gel prolonged the systemic absorption, thereby increasing the epidural availability of lidocaine for spinal analgesia. Although the absorption of ibuprofen was prolonged after epidural gel injection, the duration of analgesia as compared with the solution was not prolonged. After epidural injection, only slight inflammatory changes were observed in the tissue structures of the epidural space, but none in the spinal cord. CONCLUSIONS: These results demonstrate poloxamer gel to be a promising controlled-release, injectable epidural formulation for the management of pain.

Comparison of intrathecal morphine and continuous femoral 3-in-1 block for pain after major knee surgery under spinal anaesthesia.

Major knee surgery is associated with moderate or severe post-operative pain. Intrathecal morphine and continuous femoral 3-in-1 block were compared prospectively in 40 patients for pain after major knee surgery under spinal anaesthesia, with 4 mL isobaric 0.5% bupivacaine. In a random order, 20 patients received preservative free morphine 0.3 mg mixed with spinal bupivacaine. In 20 patients, following spinal anaesthesia with only bupivacaine, femoral 3-in-1 block was performed post-operatively with 0.5% bupivacaine 2 mg kg-1. The block was continued via a catheter with 0.25% bupivacaine 0.1 mL h-1 kg-1 until the next morning (24 h after induction of spinal anaesthesia). Intramuscular oxycodone was given as a rescue analgesic in all patients. Two patients from the femoral group were excluded due to technical failure. Three patients in the morphine group and one patient in the femoral group did not need any additional oxycodone. In the morphine group on average 2.8 (range 0-7) and in the femoral group 3.2 (0-5) additional doses of oxycodone were needed during the 24 h observation period. The mean pain scores were significantly lower in the morphine group at 9 and 12 h into the 24-h trial. Itching was seen only in the morphine group (40% of the patients). Other side effects were similar in the two groups. All patients were satisfied with their pain therapy. Both intrathecal morphine and femoral 3-in-1 block alone were insufficient for the treatment of severe pain after major knee surgery.

Comparison of respiratory effects of tramadol and pethidine.

Tramadol is a centrally acting opioid with a low affinity for mu-opioid receptors, which has been claimed not to depress respiration as do the classic opioids. The respiratory effects of intravenous (i.v.) pethidine (0.6 mg kg-1) and tramadol (0.6 mg kg-1) were compared in 36 ASA Grade I-II patients in a placebo-controlled double-blind study. After induction of anaesthesia with propofol followed by suxamethonium-facilitated endotracheal intubation, the patients spontaneously breathed halothane in 70% nitrous oxide and oxygen via a non-rebreathing valve. Inspiratory and expiratory oxygen, and end-tidal carbon dioxide concentrations (PETCO2), tidal volume (VT), minute volume of ventilation (MV) and respiratory rate were monitored by a side-stream spirometry at an end-tidal halothane of 0.3%. The recordings were collected before surgery. Pethidine caused significant respiratory depression seen as an increase in fractional inspiratory-expiratory oxygen difference and PETCO2 and as a decrease in MV and respiratory rate. However, the effects of tramadol were similar to those of a placebo. Tidal volume was not affected by any study drug. In conclusion, tramadol 0.6 mg kg-1 was shown not to be associated with respiratory depression, unlike equipotent dose of pethidine in this setting.

Perioperative analgesia with non-steroidal analgesics.

Non-steroidal anti-inflammatory drugs are widely used for perioperative analgesia as a sole analgesic after minor surgical procedures and in combination with other types of analgesics after major surgery. The development and use of new selective cyclo-oxygenase-2 inhibitors hopefully reduce the likelihood of perioperative adverse effects that may prevent the use of non-steroidal anti-inflammatory analgesics in many patients. It remains to be determined, however, whether they can offer effective analgesia with minimal risks of side-effects in everyday clinical use.

Comparison of respiratory effects of tramadol and oxycodone.

STUDY OBJECTIVE: To compare the respiratory effects of tramadol and oxycodone. DESIGN: Placebo-controlled, double-blind randomized study. SETTING: IV Department of Surgery, Helsinki University Central Hospital. PATIENTS: 36 ASA physical status I and II patients undergoing minor surgery with general anesthesia. INTERVENTIONS: The respiratory effects of intravenous (i.v.) tramadol 0.6 mg/kg and oxycodone 0.04 mg/kg were compared after induction of anesthesia with propofol and succinylcholine-facilitated endotracheal intubation. Patients spontaneously breathed halothane in 70% nitrous oxide and oxygen via a nonrebreathing valve. The trial drugs or placebo were given after recovery from neuromuscular block. MEASUREMENTS AND MAIN RESULTS: Inspiratory and expiratory oxygen and end-tidal carbon dioxide concentrations (ETCO2), tidal volume (VT) minute volume of ventilation (VE), and respiratory rate (RR) were recorded by side-stream spirometry with end-tidal halothane of 0.3% for 30 minutes before surgery. Oxycodone caused a significant respiratory depression seen as an increase in the inspiratory-expiratory oxygen difference and ETCO2 and as a decrease in VE and RR. On the contrary, the effect of tramadol were similar to those of placebo. VT was not affected by any study drug. CONCLUSION: Tramadol was not associated with respiratory depression in the present setting.

Home-readiness after spinal anaesthesia with small doses of hyperbaric 0.5% bupivacaine.

Fifty-four patients were studied prospectively to evaluate home-readiness after a small dose (1 or 2 ml) of subarachnoid hyperbaric 0.5% bupivacaine. The block regressed significantly earlier in the 1 ml group than in the 2 ml group (p < 0.05). The patients were also able to walk significantly earlier in the 1 ml group (median 161 min and 231 min in the 1 ml and 2 ml groups, respectively) (p < 0.05). However, there were no significant differences between the groups in time of ability to void. We conclude that adequate surgical anaesthesia can be achieved with small doses of hyperbaric bupivacaine used for spinal anaesthesia. Although the sensory and motor block after 1 or 2 ml hyperbaric bupivacaine recovered within a reasonable time for day-case surgery, in some patients recovery of the ability to void was delayed to an undesirable extent.

Influence of alkaline buffers on cytoplasmic pH in myocardial cells exposed to metabolic acidosis.

The influence of different clinically used alkaline buffers on cytoplasmic pH in normal as well as acidotic rat myocardial cells was investigated in this study by means of the fluorescent intracellular probe 2',7'-bis-(carboxyethyl)-5,6-carboxyfluorescein acetoxymethyl ester (BCECF-AM). It was shown that both sodium bicarbonate and Tris buffer mixture (Tribonat) caused a significant and dose-dependent acidification of the cytoplasm of suspended myocardial cells with normal initial intracellular pH. This decrease was followed by a slow increase during the observation period. The initial cytoplasmic pH value was more easily reached when Tris buffer mixture was used. Ringer's acetate also caused a decrease of intracellular pH, but this change persisted and was further amplified during the experiment. Carbicarb in larger dosages as well as pure trometamol (Tris) caused a pronounced dose-dependent and lasting intracellular alkalinization. Intracellular acidosis was achieved by preincubating the cells in sodium acetate. Addition of sodium bicarbonate caused an initial and dose-dependent acidification of the cytoplasm followed by a slow increase to values slightly above the induced acidosis. In contrast, Tris buffer mixture showed a tendency towards an initial acidification only when larger dosages were used, and correction of the induced acidosis was possible by use of moderate to large volumes. Ringer's acetate produced a lasting and dose-dependent decrease of cytoplasmic pH, while Carbicarb and pure trometamol caused an immediate, pronounced and persistent alkalinization. Myocardial cells with low initial cytoplasmic pH due to preincubation in an acid buffer also showed an early decrease of intracellular pH after addition of sodium bicarbonate and Tris buffer mixture. In the case of sodium bicarbonate correction of the acid-base disturbance was not achieved during the observation period, while this was accomplished by use of larger volumes of Tris buffer mixture. Carbicarb in larger volumes caused an increase in intracellular pH. The most significant and persistent increases of cytoplasmic pH was achieved by use of pure trometamol. In conclusion, the present in vitro study implies that Tris buffer mixture (Tribonat) is well-suited for correction of intracellular acidosis since it acts without causing a pronounced initial intracellular acidosis or a later potentially hazardous huge cytoplasmic alkalinization.

Intravenous ketorolac vs diclofenac for analgesia after maxillofacial surgery.

PURPOSE: To compare the efficacy of the non-steroidal antiinflammatory drugs (NSAID), ketorolac and diclofenac in prevention of pain after maxillofacial surgery. METHODS: Sixty ASA I-II patients (30 in each group) received randomly, and double blindly either ketorolac 0.4 mg.kg-1 or diclofenac 1.0 mg.kg-1 iv after general anaesthesia induction, before surgical incision. In the ketorolac group, the same dose was repeated iv three times at six hour intervals. The diclofenac group patients received diclofenac 1.0 mg.kg-1 after 12 hr iv. Rescue analgesic medication consisting of oxycodone 0.03 mg.kg-1 iv, was administered by a patient controlled analgesia apparatus. RESULTS: Two patients in the ketorolac and three patients in the diclofenac group did not need oxycodone during the study period. On average, 12 and 11 doses of oxycodone were needed in the ketorolac and the diclofenac groups, respectively (NS). Side-effects were similar in both groups. All patients except one were satisfied with the pain therapy. CONCLUSION: Parenteral ketorolac (0.4 mg.kg-1 four times in 24 hr) and diclofenac (1 mg.kg-1 twice in 24 hr) were similar, but insufficient alone, for analgesia after maxillofacial surgery.