Ineffective analgesia after extradural tramadol hydrochloride in patients undergoing total knee replacement

Postoperative analgesia after two extradural tramadol regimens was compared with that obtained using a standard extradural morphine regimen in patients undergoing total knee replacement. Extradural anaesthesia with light general anaesthesia was used. Patients received extradurally either: tramadol 50 mg by bolus injection followed by infusion (5 mg.h-1 for 12 h and 2.5 mg.h-1 for a further 12 h) (group T50), tramadol 100 mg by bolus injection followed by infusion (10 mg.h-1 for 12 h and 5 mg.h-1 for a further 12 h) (group T100) or morphine sulphate 2 mg by bolus injection followed by infusion (0.2 mg.h-1 for 12 h and at 0.1 mg.h-1 for further 12 h) (group M). Analgesia was allocated according to a controlled double-blind design. Visual analogue pain scores were markedly poorer (p < 0.05) and patient-controlled analgesic consumption was significantly greater (p < 0.01) in the two tramadol groups when compared with the morphine group. The study was discontinued after recruitment of 12 patients, as analgesia was deemed inadequate in those receiving tramadol extradurally. However, further study of this drug may be warranted to examine its effectiveness where postoperative pain is expected to be less severe, and to assess the effect of larger extradural doses and of co-administration of tramadol and morphine by this route.

Low gastric intramucosal pH: incidence and significance in intensive care patients

Monitoring of gastric intramucosal pH (pHi) is advocated in critical illness to detect tissue acidosis due to regional hypoperfusion. However, the number of patients who may benefit from such monitoring remains unclear and the relationship between low pHi and outcome requires further definition. Sixty consecutive patients with Acute Physiology and Chronic Health Evaluation (APACHE II) scores < 30 were studied throughout ICU stay to investigate the incidence of low pHi (< 7.32 for > or = 1 hour), its relationship to outcome, and temporally associated clinical events. pHi was measured 2 to 6 hours post-ICU admission and 8-hourly thereafter. Forty-four patients (73%) exhibited low pHi. Fourteen patients died in ICU with 13 deaths occurring in the low pHi group (P = 0.05). Length of ICU stay was greater in the low pHi group (P = 0.02). The development of low pHi was temporally associated with maximal sepsis score, weaning from assisted ventilation and commencement of enteral feeding.

Uptake of halothane and isoflurane by mother and baby during caesarean section

Twenty-three patients undergoing Caesarean section received either 0.5% halothane or 0.8% isoflurane to supplement nitrous oxide-oxygen anaesthesia. We studied the rate of uptake of the agents by the mother and fetus by measuring partial pressures in maternal arterial (Pa) and fetal umbilical venous (Puv) blood. Mean induction-delivery interval did not differ between the halothane (10.8 min) and isoflurane (11.7 min) groups. There were no differences in maternal heart rate, arterial pressure, pH and blood-gas tensions and fetal pH, blood-gas tensions or Apgar scores between the two groups. Isoflurane uptake by the mother was more rapid than halothane; at delivery, mean Pa of isoflurane as a fraction of the inspired partial pressure (Pl) was 0.44 compared with 0.35 for halothane (P < 0.05). Mean Puv as a fraction of maternal Pa at delivery was 0.71 for both agents; thus placental transfer was the same for both agents. Consequently mean Puv/Pl was greater for isoflurane (0.32) than halothane (0.26) (P < 0.05). We conclude that both halothane and isoflurane are suitable agents for general anaesthesia for Caesarean section. The rate of uptake of isoflurane by the mother during Caesarean section was more rapid than halothane. The rate of uptake by the fetus from the mother was the same for halothane and isoflurane, so that fetal partial pressure as a fraction of the inspired partial pressure was greater for isoflurane than halothane.

Correction of splanchnic oxygen deficit in the intensive care unit: dopexamine and colloid versus placebo

Correction of the splanchnic oxygen deficit indicated by low gastric intramucosal pH (pHi < 7.35) appears to reduce ICU mortality. Dopexamine hydrochloride is in clinical use for this purpose but its efficacy has not been fully investigated. We report the results of a prospective, randomized, placebo-controlled study with a crossover design to assess the efficacy of dopexamine in correcting low pHi. Twelve patients in whom pHi < 7.32 was detected during eight-hourly monitoring were randomized to receive either incremental dopexamine (4-6 micrograms/kg/min) with colloid or 5% dextrose for three hours prior to crossover. There was no difference in pHi between treatments despite cardiovascular effects during dopexamine infusion. There was, however, a time-related increase in pHi suggesting a beneficial effect of conventional therapy. Dopexamine hydrochloride at 4-6 micrograms/kg/min in conjunction with colloid is not a clinically useful therapy to correct the splanchnic oxygen deficit indicated by low pHi.

Postoperative analgesia after co-administration of clonidine and morphine by the intrathecal route in patients undergoing hip replacement

Postoperative analgesia after intrathecal co-administration of clonidine hydrochloride (75 micrograms) and morphine sulfate (0.5 mg) was compared with analgesia produced after either intrathecal morphine (0.5 mg) or 0.9% sodium chloride in 90 patients undergoing total hip replacement under bupivacaine spinal anesthesia. Patient-controlled morphine requirements were significantly reduced (P < 0.001) postoperation by both clonidine/morphine (median 5 mg/24 h) and morphine (median 7 mg/24 h) compared with control (saline) (median 28 mg/24 h). However, no significant additional reduction in postoperative analgesic requirements was shown with the clonidine/morphine combination compared with morphine alone. Visual analog pain scores, although good in all groups at all times, were significantly poorer in the control group at 2 h (P < 0.04) and 4 h (P < 0.001) after operation compared with both treatment groups, and significantly poorer than the clonidine/morphine group at 6 h (P < 0.002) and 24 h (P < 0.009) postoperation. Mean arterial blood pressure was significantly lower in the clonidine/morphine group than in the two other groups (P < 0.001) between 2 and 5 h after operation. The incidence of emesis was similar in the clonidine/morphine and morphine groups and was significantly more than in the control group.

Co-administration of pethidine and clonidine: a spinal anaesthetic technique for total hip replacement

Co-administration of pethidine 0.75 mg kg-1 and clonidine 75 micrograms intrathecally provided good intraoperative anaesthesia for total hip replacement, similar to that obtained using 0.5% isobaric bupivacaine. Sensory and motor block were of shorter duration than that after 0.5% isobaric bupivacaine and 0.5% isobaric bupivacaine with morphine 0.5 mg (P < 0.001 sensory block, P < 0.001 motor block). Postoperative morphine consumption, measured using a patient-controlled system, was similar to that in patients in the bupivacaine only group (pethidine-clonidine: median 39 mg/24 h; bupivacaine: median 34 mg/24 h) but greater than that in the bupivacaine-morphine group (median 8 mg/24 h) (P < 0.001). Visual analogue pain scores after operation were similar to those with bupivacaine alone at all but one of the recording times but were greater than those in patients who received bupivacaine and morphine at 4, 6 and 10 h after operation (P < 0.001, P < 0.04, P < 0.02). The combination did not offer any major advantage over conventional agents.

Intensive care management of multiple-organ dysfunction due to falciparum malaria in a married couple

A married couple presented simultaneously with malignant tertian malaria and rapidly developed septicaemia and severe multiple-system organ failure. Despite schizonticidal treatment and multisystem support in intensive care the husband died. The selection of chemoprophylactic agents for this couple was not ideal and the duration of therapy before exposure to risk was inadequate. Severe infection with plasmodium falciparum is life-threatening and requires early diagnosis. It is best managed in an intensive care unit where continuous assessment may enable rapid detection of clinical deterioration and allow appropriate treatment to be instituted. The diagnosis should be considered in symptomatic patients who have travelled through areas where malaria is endemic. Recognised guidelines for the prescription of malarial chemoprophylaxis should be followed to ensure adequate protection.

Comparison of the effects of isoflurane and propofol on hepatic glutathione-S-transferase concentrations during and after prolonged anaesthesia

We have studied the effects of isoflurane or propofol anaesthesia on hepatic glutathione-S-transferase (GST) concentrations in 20 patients during and after prolonged plastic and reconstructive surgery (approximately 10 h). Mean plasma concentrations of GST did not exceed the normal range in any sample from any patient. Although GST concentrations in the propofol group were smaller than those in the isoflurane group, these differences were not statistically significant. These data show that prolonged propofol or isoflurane anaesthesia has no statistically significant effect on plasma concentrations of GST during and after extended surgery.

Cardiovascular effects of isoflurane and halothane in young and elderly adult patients

We have studied the cardiovascular effects of 1 MAC end-tidal concentrations of halothane and isoflurane in young (n = 40) and elderly (n = 40) adult patients using non-invasive techniques. Cardiac output was measured by Doppler ultrasonography. Halothane reduced heart rate, systolic, mean and diastolic arterial pressures and cardiac index in both age groups (P < 0.05). Isoflurane reduced systolic, mean and diastolic arterial pressures also, but reduced cardiac index and heart rate only in the older patients (P < 0.05). Halothane depressed cardiovascular state significantly more than isoflurane in the younger adults (P < 0.05), but cardiovascular depression was similar for the two agents in the older age group. The decreases in systolic and diastolic pressures in the older patients were significantly greater with isoflurane compared with halothane (P < 0.05).

Neuromuscular effects and intubating conditions following mivacurium: a comparison with suxamethonium

Mivacurium chloride has been assessed in respect of intubating conditions and neuromuscular effects. The influence of suxamethonium on the onset and duration of subsequently administered mivacurium was also studied. A dose of 0.15 mg.kg-1 of mivacurium was found to provide unacceptable intubating conditions at 2 min in 9/9 patients and further studies were conducted using 0.2 mg.kg-1. Intubating conditions with this dose were acceptable in 65% and 80% of patients at 2 min and 2.5 min respectively. In comparison, intubating conditions were acceptable in 100% of patients at 1 min following 1 mg.kg-1 of suxamethonium. The onset of block occurred in 96 s and 97 s after 0.15 mg.kg-1 and 0.2 mg.kg-1 respectively, and the durations of block in terms of recovery of the first twitch (T1) to 25% and 90% of control, and to recovery of train-of-four ratio to 0.7, were 16.1 and 17.9; 24.1 and 25.8; and 24.2 and 27.0 min respectively with the two doses. The time for the onset of complete block with suxamethonium 1.0 mg.kg-1 was 50 s and the times to 25% and 90% recovery were 9.8 min and 13.3 min. The differences between suxamethonium and both doses of mivacurium were significant (p < 0.05) but there were no significant differences between the two doses of mivacurium in any of the neuromuscular measurements. Prior administration of suxamethonium had no influence on the effects of mivacurium. Cutaneous flushing was observed in 30 out of 75 patients but this was associated with transient hypotension in only two patients.(ABSTRACT TRUNCATED AT 250 WORDS)

A preliminary assessment of epidural chloroprocaine for day procedures

Twenty-five patients underwent epidural anaesthesia with a new formulation of chloroprocaine 3% (1.0-1.5 ml x 10 cm body height-1) for a variety of day procedures. The mean (range) duration of surgery was 17 (5-35) min. The mean (range) time taken to establish maximal block was 16 (15-21) min and the mean (range) time to ambulation was 78 (55-95) min after administration of chloroprocaine. Twenty-three patients experienced a decrease in systolic arterial blood pressure of up to 15% of baseline values with another two decreasing by up to 25%. Two patients complained of severe backache immediately after operation and a further 16 and four patients reported mild or moderate backache respectively. Operating conditions were excellent in all but one patient and 23 patients said they would be happy to have the same anaesthetic again.

Pain on injection of propofol: comparison of lignocaine with metoclopramide

We have conducted a randomized, double-blind study in 255 ASA I and II patients to compare the efficacy of lignocaine and metoclopramide in minimizing the pain of injection of i.v. propofol. When administered immediately before propofol into a dorsal hand vein, compared with placebo both drugs significantly reduced the incidence of pain on subsequent injection of propofol (P < 0.001). Twenty patients who had received metoclopramide (n = 85) experienced pain, compared with 18 who had received lignocaine (n = 85) and 42 who had been pretreated with saline (n = 85).

The influence of particle size on the bioavailability of inhaled temazepam

1. Temazepam was administered by aerosol using a standard protocol to healthy volunteers. Two studies are reported in which different dosage formulations were used: a) 30 mg of the 5 mu diameter particle (n = 6); b) 10 mg of the 2 mu diameter particle (n = 6). 2. An open crossover design was followed in each study. On one occasion in both studies subjects used a gargling procedure to remove drug which had been deposited in the mouth and oropharynx. 3. Serial venous blood samples were drawn for a period of 24 h. The mean total AUC of the 5 mu preparation was significantly reduced by gargling (3153 ng ml-1 h to 1066 ng ml-1 h) (F = 0.32). Gargling also had a significant effect on the mean AUC(0-1 h). 4. In contrast gargling had no significant effect on the mean AUC associated with the smaller diameter particle preparation (630 ng ml-1 h) vs 397 ng ml-1 h (F = 0.74). 5. These findings also indicate that temazepam deposition in the pulmonary tree is enhanced by the use of a 2 mu rather than a 5 mu diameter particle. However, the plasma drug concentrations achieved are unlikely to produce a sufficiently marked sedative effect for endoscopic investigations such as gastroscopy.

Cardiovascular support during combined extradural and general anaesthesia

We have examined the effect of prophylactic treatment with i.v. fluid 1000 ml, ephedrine 24 mg or methoxamine 4 mg on cardiovascular responses to both extradural and combined extradural and general isoflurane anaesthesia in 45 adult patients undergoing knee arthroplasty. Heart rate (HR) and systemic arterial pressure (AP) were measured using automated oscillotonometry and cardiac output was measured using continuous wave suprasternal Doppler ultrasonography. After lumbar extradural anaesthesia (LEA) there were no significant differences in arterial pressure between treatments, although cardiac index was significantly greater after fluid preloading (mean 4.3 (95% confidence interval 3.7-4.9) litre min-1 m-2) than after ephedrine (3.1 (2.6-3.6) litre min-1 m-2) or methoxamine (2.6 (2.0-3.2) litre min-1 m-2). During combined LEA and general anaesthesia, systolic AP was significantly greater after ephedrine (114 (103-125) mm Hg) than after either preloading (98 (88-107) mm Hg) or methoxamine (97 (89-105) mm Hg). The reduction in AP after induction of general anaesthesia was associated with a decrease in cardiac index after fluid preloading and a decrease in vascular resistance after methoxamine.

Arterial washin of halothane and isoflurane in young and elderly adult patients

We have studied the effect of age on washin of isoflurane and halothane by comparing end-tidal (PE') and arterial (Pa) partial pressures of the agents in young (18-32 yr) and elderly (63-82 yr) healthy patients for 20 min after introduction of the agents, before surgery. PE' was measured by infra-red analysis and Pa by gas chromatography. Washin of isoflurane occurred at the same rate in the young and elderly, with no significant difference between young and elderly in PE' or Pa as proportions of the inspired partial pressure (PI). After 20 min of isoflurane administration, mean Pa/PI in the young was 0.57 (95% confidence limit (CL) 0.53-0.62) and 0.55 in the elderly (95% CL 0.51-0.59). Washin of halothane was slower in the elderly than in the young, with Pa/PI significantly less in the elderly from 10 min after introduction of halothane. The difference between age groups, however, was small: mean Pa/PI after 20 min of halothane administration 0.45 (95% CL 0.41-0.49) in the young and 0.38 (95% CL 0.35-0.41) in the elderly. Washin of isoflurane was significantly faster than that of halothane in both young and elderly subjects. For isoflurane, the PE'-Pa gradient was small relative to Pa and did not differ significantly between young and elderly. For halothane, PE'-Pa in the young did not differ significantly from that for isoflurane. In the elderly, PE'-Pa for halothane was significantly greater than in the young and than PE'-Pa for isoflurane.

Diclofenac for day-care arthroscopy surgery: comparison with a standard opioid therapy

Sixty unpremedicated patients presenting for day-care arthroscopy surgery were allocated randomly to receive diclofenac 1 mg kg-1 i.m., fentanyl 1 microgram kg-1 i.v. or no analgesic during the course of anaesthesia. Patients receiving fentanyl had slightly, although not significantly prolonged recovery times. Patients receiving diclofenac had significantly improved postoperative visual analogue pain scores compared with patients receiving placebo medication (P less than 0.05). With fentanyl, pain scores were reduced also, but the effect was not statistically significant. Both fentanyl and diclofenac produced significant reduction in postoperative analgesic requirements (P less than 0.05). We conclude that diclofenac 1 mg kg-1 i.m. was an effective analgesic for arthroscopic procedures on the knee and is a useful alternative to opioids for day-care patients.

End-tidal concentrations of halothane and isoflurane during induction of anaesthesia in young and elderly patients

Twenty-two young (18-32 yr) and 22 healthy elderly (60-80 yr) patients received either halothane or isoflurane for maintenance of anaesthesia during controlled ventilation. End-tidal fractional concentrations (FE) of the agents were measured for 20 min after their introduction into inspired gas and the increase in end-tidal concentrations of the two agents was compared during induction of anaesthesia using the ratios of FE to the inspired fraction (FI). FE:FI ratios for isoflurane were higher than those for halothane in both young and elderly patients, confirming that equilibration of end-tidal with inspired concentration occurs more rapidly with isoflurane than with halothane in both age groups. FE:FI ratios for isoflurane became significantly lower in the elderly than in the young after 15 min administration of isoflurane. This suggests slower induction of anaesthesia in the elderly if equipotent concentrations of isoflurane are used; the clinical significance of this difference is probably small. Mean FE:FI ratios for halothane in elderly patients were similar to those in the young throughout induction of anaesthesia.

Analgesia after hip replacement surgery: comparison of nalbuphine with morphine

Two groups of 40 patients undergoing hip replacement received either nalbuphine 0.3 mg kg-1 or morphine 0.15 mg kg-1 i.m. on up to three occasions: 1 h before operation, as soon as requested after operation, and 3 h subsequently if required. Pain intensity was assessed by the patient as severe, moderate or none, and pain relief by a "blind" nurse observer as slight, moderate or complete. Assessments of pain and sedation were carried out at 30-min intervals for 2 h and at 1-h intervals thereafter for up to 6 h. Six patients who received nalbuphine and eight who received morphine before operation required no postoperative analgesia. Ten patients in the nalbuphine group and two in the morphine group failed to obtain adequate pain relief (P less than 0.05) and were given i.v. morphine.

Factors that influence cutaneous reactions following administration of thiopentone and atracurium

Atracurium was administered by a variety of techniques to determine whether these influence the onset or duration of muscular relaxation, and the frequency of cutaneous reactions, after a standard induction dose of thiopentone. One-hundred-and-fifty patients were allocated randomly to receive the drug by one of five methods: into a fast-flowing crystalloid infusion in the antecubital fossa; into a winged needle in the antecubital fossa with flushing after the thiopentone; into a winged needle in the antecubital fossa without flushing; into a winged needle in the dorsum of the hand without flushing. The above groups received atracurium freshly removed from the refrigerator whereas the fifth group were given atracurium which had been maintained at room temperature for at least 2 weeks. The frequency of cutaneous reactions was between 60 and 70% overall and there were no significant differences either in this or in the onset or duration of action between the groups. A further 25 patients with a history of drug allergy were also investigated by the first method and showed no significant differences in response, but 25 patients aged over 70 years had a significantly lower frequency of cutaneous reactions with a higher frequency of hypotension than the other groups.

Cimetidine and ranitidine increase midazolam bioavailability

Cimetidine has been shown to inhibit the oxidative metabolism of a variety of low- and high-extraction drugs. Despite the findings of initial investigators, there is evidence that ranitidine may exert similar effects. Eight healthy volunteer subjects took part in a within-subject crossover study. They received midazolam, 15 mg, by mouth after pretreatment with cimetidine, ranitidine, or nothing and midazolam, 10 mg, intravenously on separate occasions. Mean absolute bioavailability of midazolam was increased by more than 30% after cimetidine (P less than 0.01) and 26% after ranitidine (P less than 0.05). The data, which agree with a concurrent clinical study indicating greater hypnotic action of midazolam after ranitidine, indicate that this is not a result of enhanced midazolam absorption and that reduced hepatic clearance is the most likely explanation.

Bioavailability of three formulations of intravenous diazepam

It has been generally assumed that the bioavailability of different formulations of intravenous diazepam is identical. In a within-subject crossover study using eight healthy volunteers, we have found that both the initial and the overall plasma diazepam levels are significantly lower after both emulsion (Diazemuls) and micelle preparations than after an organic formulation (Valium). These findings are relevant to the interpretation of the results of past, present and future clinical studies involving intravenous diazepam. The studies with Valium and Diazemuls confirm the clinical impression of the lesser potency of the latter formulation.