Search PubMed⌕ Search

Biomedical subjects

T Gin

Publications and source records attributed to T Gin.

At least 37 records · Page 2Linked to original sources
PubMed1999

Continuous infusion ceftazidime in intensive care: a randomized controlled trial.

We randomized 18 critically ill patients to receive ceftazidime 6 g/day by continuous infusion or bolus dosing (2 g 8 hourly), each with a loading dose of 12 mg/kg ceftazidime. During the first 8 h, plasma ceftazidime concentration fell below 40 mg/L in only one patient (trough 38 mg/L) from the infusion group, compared with eight from the bolus group (2-33 mg/L) for periods ranging from 73 to 369 min. Thereafter all infusion patients remained above 40 mg/L for 40 h of study versus 20-30% of bolus patients. The pharmacokinetic and pharmacodynamic characteristics of ceftazidime suggest that continuous infusions should be clinically investigated in outcome studies.

Adult↗
PubMed1999

Propofol requirement is decreased in patients with large supratentorial brain tumor.

BACKGROUND: The anesthetic requirement is decreased in animals with head injury, but there are no data regarding the effect of intracranial tumor on the potency for intravenous anesthetics. The authors compared the quantal dose-response curves for propofol in patients having large (> or = 30 mm, mass effect) brain tumor with those having smaller (< 30 mm) lesions and with control patients undergoing noncranial surgery. METHODS: Sixty patients in each group were randomly assigned to receive one of the six doses of propofol (0.5, 0.7, 1.0, 1.3, 1.8, or 2.5 mg/kg) over 10 s. Two minutes after drug administration, patients were asked to open their eyes as a test for response to verbal command. Patients who failed to respond were given a 10-s, 50-Hz, 80-mA transcutaneous tetanic electrical current to the ulnar nerve as a test for response to painful stimulus. Purposeful movement indicated positive response. Log dose-response curves for loss of response to verbal command and tetanic stimulus were calculated after logit transformation. RESULTS: The median effective doses (ED50s; 95% confidence interval) for suppressing response to verbal command and tetanic stimulus were 0.75 (0.65-0.86) mg/kg and 1.28 (1.11-1.49) mg/kg, respectively, in patients with large brain tumor. These values were significantly less than the corresponding ED50s in patients with small tumor, 1.01 (0.88-1.15) mg/kg and 1.76 (1.51-2.07) mg/kg, or healthy control subjects, 0.98 (0.86-1.12) mg/kg and 1.89 (1.62-2.23) mg/kg. CONCLUSIONS: The doses of propofol required to suppress response to verbal command and tetanic stimulus were 23% less and 32% less in patients with large brain tumor compared with control subjects. Small tumor did not affect potency of propofol.

Adolescent↗
PubMed1999

Long-term drusen study.

PURPOSE: To determine the yearly incidence of visual loss in the fellow eyes of patients with unilateral neovascular age-related macular degeneration (ARMD) and to assess the drusen characteristics portending the greatest risk for this outcome. METHODS: A total of 101 patients with unilateral exudative ARMD and drusen only in the fellow eye were entered into the study and prospectively followed up to 9 years. Visual acuity, color fundus photography, fluorescein angiography, and grading of drusen characteristics were obtained for each patient on entry into the study. Patients were followed at annual intervals with color fundus photography. The study endpoint was the development of choroidal neovascularization (CNV) or geographic atrophy (GA) in the fellow eye. RESULTS: Yearly incidence rates for the development of an endpoint lesion were between 5 and 14%. The risk of CNV peaked at 4 years and dissipated thereafter. Longer follow-up was associated with a slightly increased incidence of GA. Greater drusen number was most highly associated with the development of an endpoint lesion. Drusen size and confluence were also significant. CONCLUSIONS: The risk of CNV in patients with ARMD is heralded by an increase in the number, size, and confluence of drusen. This risk eventually declines and is followed by later increased risk of GA.

Aged↗
PubMed1999

Induction of anaesthesia in patients with coronary artery disease: a comparison between sevoflurane-remifentanil and fentanyl-etomidate.

In a prospective, randomized study, sevoflurane-remifentanil (Group SR) was compared with fentanyl-etomidate (Group FE) for induction of anaesthesia in patients with ischaemic heart disease. Cardiovascular stability, heart rate, mean arterial pressure, rate pressure product, rescue medications and associated myocardial ischaemia were measured. For Group SR (n = 20), anaesthesia was induced with vital capacity breaths of sevoflurane 5% in oxygen. After loss of consciousness, the inspired sevoflurane was reduced to 3% and remifentanil was administered as a 0.5 microgram.kg-1 bolus over 90 seconds (0.33 microgram.kg-1.min-1) followed by a 0.025 microgram.kg-1.min-1 infusion. After intubation, the inspired sevoflurane was reduced to 2%. For Group FE (n = 20), anaesthesia was induced with fentanyl 10.5 micrograms.kg-1 and etomidate 0.2 mg.kg-1 given 60 seconds later. Isoflurane 1% in oxygen was administered after loss of consciousness. Both groups received rocuronium and the trachea was intubated two minutes later. Sevoflurane gaseous induction was smooth, with cardiovascular stability comparable to fentanyl-etomidate. Significantly more patients in Group SR (P < 0.05) were on beta-blocking medication, and, overall, the HR and RPP was lower pre-intubation in Group SR. Remifentanil administration was associated with severe bradycardia in three patients and asystole in a fourth. All four patients were on beta-blocking medication and three of the four were on diltiazem. The study was terminated due to the high incidence of bradycardic/asystolic complications in Group SR.

Adrenergic beta-Antagonists↗
PubMed1998

Postpartum patients have slightly prolonged neuromuscular block after mivacurium.

UNLABELLED: Postpartum patients have decreased plasma cholinesterase activity, which may slow the metabolism of mivacurium. We compared the duration of a mivacurium neuromuscular block in 11 women undergoing postpartum tubal ligation 36-99 h after delivery with that in 11 control women undergoing gynecological surgery. Anesthesia was induced with propofol and fentanyl and maintained with propofol and nitrous oxide. Neuromuscular block was monitored by electromyography, and the ulnar nerve was stimulated transcutaneously using a train-of-four pattern. Patients received a bolus dose of mivacurium 0.15 mg/kg. The median (range) duration of neuromuscular block until 25% recovery of the first twitch response was longer in the postpartum group, 19.4 (15.6-25.2) min, compared with the control group, 16.3 (11.0-23.4) min (P = 0.04). The median (range) plasma cholinesterase activity was decreased in the postpartum group, 4.0 (0.1-5.5) kU/L, compared with the control group, 7.1 (6.2-10.0) kU/L (P < 0.001). The duration of neuromuscular block was inversely correlated with cholinesterase activity (Kendall rank correlation tau = -0.43, P = 0.005). The slight prolongation of neuromuscular block should not be significant clinically. IMPLICATIONS: Postpartum patients have decreased amounts of the plasma cholinesterase enzyme. This would slow the metabolism of the muscle relaxant mivacurium. However, the duration of muscle paralysis is only prolonged by approximately 3 min, which would not normally cause any significant problems.

Adult↗
PubMed1998

A comparison of the Hamamatsu NIRO 500 and the INVOS 3100 near-infrared spectrophotometers.

Near-infrared spectroscopy is a technique used for non-invasive measurement of cerebral oxygenation and a number of commercial devices are currently available for use. We compared measurements of cerebral oxygenation made with two near-infrared spectrophotometers--the Somanetics Invos 3100 cerebral oximeter and the Hamamatsu NIRO-500 near-infrared spectrophotometer. Hypoxia was induced in six healthy male volunteers with and without occlusion of scalp blood flow. Oxygen saturation, end-tidal carbon dioxide tension, regional cerebral oxygen saturation, change in regional cerebral oxyhaemoglobin concentration and change in regional cerebral total haemoglobin concentration were measured. The INVOS 3100 displays cerebral oxygen saturation directly. The NIRO-500 displays change in total haemoglobin concentration and oxyhaemoglobin concentration, and the cerebral oxygen saturation was calculated offline. Statistical analysis disproved the assumption that the INVOS 3100 and the NIRO-500 were measuring the same changes in cerebral oxygenation. Neither machine can be confirmed for reliability against a gold standard and operational difficulties mean that neither can be recommended for routine clinical use.

Brain↗
PubMed1997

Intermittent bolus dosing of ceftazidime in critically ill patients.

Ceftazidime is frequently used in critically ill patients, particularly for the treatment of Pseudomonas aeruginosa infections. The recommended dosing regimen is based on pharmacokinetic data obtained in healthy volunteers and may not be appropriate in the critically ill. We administered ceftazidime in the maximum recommended dose (2 g i.v. every 8 h) to ten critically ill patients with normal plasma creatinine. Eighteen arterial blood samples were taken from each patient over the first 8 h for measurement of ceftazidime concentrations and subsequent compartmental pharmacokinetic analysis. An additional trough sample was taken from each patient on day 3. Although mean pharmacokinetic variables did not differ from previously reported data in normal volunteers there was wide variability in plasma drug concentrations. Three of our patients had plasma ceftazidime concentrations less than the MIC for P. aeruginosa (8 mg/L) and nine had concentrations less than 5 x MIC, which has been recommended to ensure efficacy. On day 3 trough ceftazidime concentrations were less than the MIC in four out of the seven patients in whom measurements were made and less than 5 x MIC in the remaining three. There was no clinical predictor of which patients would have low plasma concentrations. Our results show that plasma concentrations of ceftazidime are very variable when the recommended intermittent bolus dosing regimen is used and may result in inadequate plasma concentrations of drug in critical infections. This may result in treatment failure and the emergence of antibiotic resistance. A loading dose followed by continuous infusion should overcome these problems but this awaits in-vivo evaluation.

Adult↗
PubMed1997

Epidural meperidine after cesarean section: the effect of diluent volume.

We investigated the effect of diluent volume on analgesia and systemic absorption from epidural meperidine after cesarean section in a randomized, double-blind study. At the first request for postoperative analgesia, 36 parturients were given epidural meperidine 25 mg diluted with saline to either 2 mL (12.5 mg/mL), 5 mL (5 mg/mL), or 10 mL (2.5 mg/mL). Visual analog pain scores measured in the first 30 min were greater in the 2-mL group compared with both the 5-mL group (P = 0.028) and the 10-mL group (P = 0.031). Onset of analgesia (time for visual analog pain scores to decrease by 50%) was also slower in the 2-mL group (17.5 min) compared with the 5-mL group (9 min; P = 0.015) and the 10-mL group (12 min; P = 0.003); there were no differences between the 5-mL group and the 10-mL group. Duration of analgesia and plasma concentrations of meperidine were similar among groups. No adverse side effects were recorded. Previous work has suggested that injection of epidural opioids in large volumes increases the potential risk of respiratory depression from cephalad spread of the drug. Therefore, we conclude that analgesia is optimum when epidural meperidine is administered diluted to 5 mL.

Absorption↗
PubMed1997

Postoperative analgesic requirement after cesarean section: a comparison of anesthetic induction with ketamine or thiopental.

UNLABELLED: In a randomized, double-blind study, we compared postoperative pain and analgesic requirement in patients who underwent elective cesarean section under general anesthesia induced with thiopental 4 mg/kg (n = 20) or ketamine 1 mg/kg (n = 20). Anesthesia was maintained with nitrous oxide and isoflurane. Postoperative analgesia was provided by patient-controlled analgesia (PCA) using morphine. Median (range) time to first PCA demand was greater in the ketamine group (28 [3-134] min) compared with the thiopental group (20.5 [3-60] min; P = 0.04). Median (range) morphine consumption over 24 h was less in the ketamine group (24.3 [3-41] mg) compared with the thiopental group (35 [4-67] mg; P = 0.017). Visual analog scale pain scores were similar between groups. No patients had recall of intraoperative events or unpleasant dreams. Two patients in the thiopental group and one patient in the ketamine group had pleasant intraoperative dreams. Apgar scores were similar between groups. Median umbilical venous pH was higher (7.33 vs 7.31; P = 0.04) and attributable to lower median umbilical venous Pco2 (5.72 vs 6.14 kPa; P = 0.02) in the ketamine group compared with the thiopental group. Induction of anesthesia for cesarean section using ketamine is associated with a lower postoperative analgesic requirement compared with thiopental. IMPLICATIONS: Patients who had anesthesia for cesarean section induced with ketamine required less analgesic drugs in the first 24 h compared with patients who received thiopental. Ketamine, unlike thiopental, has analgesic properties that may reduce sensitization of pain pathways and extend into the postoperative period.

Adult↗
PubMed1997

Decreased thiopental requirements in early pregnancy.

BACKGROUND: Anesthetic requirements for inhalational agents are decreased during pregnancy, but there are no data regarding requirements for intravenous agents. The quantal dose-response curves for thiopental were calculated for 70 nonpregnant women having gynecologic surgery and for 70 pregnant women of 7-13 weeks' gestation having elective abortions. METHODS: Groups of 10 patients were given 2, 2.4, 2.8, 3.3, 3.8, 4.5, or 5.3 mg/kg thiopental as a bolus dose during a period of 10 s. Two minutes later, patients were asked to open their eyes as a test for hypnosis. Patients who did not open their eyes were given a 10-s, 50-Hz, 80-mA transcutaneous tetanic electrical stimulus to the ulnar nerve as a test for anesthesia. Purposeful movement indicated that there was no anesthesia. Log dose-response curves for hypnosis and anesthesia were calculated after logit transformation. RESULTS: In the nonpregnant women, the median effective doses (ED50s) (95% confidence interval) for hypnosis and anesthesia were 3.1 (2.8-3.4) mg/kg and 4.9 (4.5-5.4) mg/kg, whereas in the pregnant women the corresponding ED50s were 2.6 (2.3-2.8) mg/kg and 4 (3.7-4.4) mg/kg. In the non-pregnant women, the ED95s (95% CI) for hypnosis and anesthesia were 4.4 (3.9-5.4) mg/kg and 6.4 (5.7-7.9) mg/kg, whereas in the pregnant women the corresponding ED95s were 3.7 (3.3-4.5) mg/kg and 5.2 (4.7-6.3) mg/kg. The pregnant to nonpregnant relative median potency (95% CI) ratio for hypnosis was 0.83 (0.67-0.96) and for anesthesia it was 0.82 (0.62-0.94). CONCLUSIONS: The dose of thiopental for hypnosis was 17% less and that for anesthesia was 18% less in pregnant women of 7-13 weeks' gestation compared with that in nonpregnant women.

Adult↗
PubMed1997

Computer-controlled infusion of propofol for long neurosurgical procedures.

This study evaluated the performance of a computer-controlled infusion (CCI) system for propofol during long neurosurgical procedures. Anesthesia was induced and maintained in 15 patients using a CCI of propofol. The initial target concentration was set at 3 micrograms/ml, and this was then titrated according to the clinical situation. A total of 284 blood samples were taken for propofol assay. The performance of the system during anesthesia, assessed using the median performance error (MDPE), median absolute performance error (MDAPE), wobble, and divergence, were -5.3%, 20.6%, 9.0%, and 0.3%/h, respectively. MDPE and MDAPE during the first 20 min after stopping the infusion were -38.7% and 39.0%, respectively. The CCI system did not show significant changes in predictive ability, with time during anesthesia lasting up to 12 h. Changes in the measured blood concentration were in the same direction as changes in the target concentration.

Adolescent↗
PubMed1997

Uterine rupture and epidural analgesia during trial of labour.

A case of complete uterine rupture during a trial of labour in which epidural analgesia was used is described. The pain of uterine rupture was not masked by the addition of fentanyl 25 micrograms to bupivacaine 0.25% 6 ml but was relieved by bupivacaine 0.375% 6 ml.

Adult↗
PubMed1997

Comparison of patient-controlled epidural analgesia with patient-controlled intravenous analgesia using pethidine or fentanyl.

We compared patient-controlled epidural analgesia (PCEA) with patient-controlled intravenous analgesia (PCIA) using pethidine or fentanyl in a randomized, double-blind crossover study of 80 patients after caesarean section. Patients received pethidine by PCEA or PCIA, or fentanyl by PCEA or PCIA, with a crossover of the route of administration at 12h. For pethidine, pain scores were lower with PCEA vs PCIA from 4 to 16h (P < 0.05). Pethidine consumption was lower with PCEA vs PCIA from 12 to 24h (P = 0.0005). Patients preferred PCEA to PCIA (P = 0.015). For fentanyl, pain scores were lower with PCEA vs PCIA at 12h (P = 0.045). Fentanyl consumption was lower with PCEA vs PCIA from 0 to 12h (P = 0.0007). Patients had similar preference for PCEA and PCIA. Pain scores and side-effects were similar between drugs. Plasma pethidine was similar between groups. Plasma fentanyl was higher with PCIA vs PCEA at 12h (P = 0.002). PCEA has advantages over PCIA and pethidine may be the preferred drug.

Analgesia, Epidural↗
PubMed1997

Opioid requirements and responses in Asians.

The provision of good analgesia can be influenced by ethnic differences in how pain is expressed, the attitudes of patients and health professionals towards pain management and pharmacological differences in the responses to opioids. It is difficult to generalize results so that they are applicable to any ethnic group as a whole. There is also the question of how best to categorize ethnic Asians who have been in Australasia for several generations. Much of the pharmacogenetic work has focused on the metabolism of codeine, morphine and pethidine, and there are some differences between Chinese and Caucasians. Asians may receive less analgesia because they are more likely to experience, or are less tolerant of the adverse effects of opioids. Despite this, ethnic factors are probably only a small contributor to the inter-individual variation in opioid requirements. Unlike earlier studies, recent larger studies using patient-controlled analgesia have shown similar opioid usage between Asians and Caucasians in the postoperative period. An individualized pain management program is essential for any patient, whatever his or her ethnic origin. The use of patient-controlled analgesia will minimize some of the problems that may occur because of poor communication between the patient and the healthcare staff. Nevertheless, in a multicultural society like Australia's, health professionals should be conscious of the many factors that may influence the effects of prescribed treatment to manage pain in different ethnic groups.

Analgesia↗
PubMed1997

Patient-controlled epidural analgesia after caesarean section using a disposable device.

We have evaluated the use of a disposable device, the Patient Controlled Epidural Infusor, for patient-controlled epidural analgesia (PCEA) using pethidine, for pain relief in the first 24 hours after elective Caesarean section. Patients using the Patient Controlled Epidural Infusor (n = 20) were compared with a control group (n = 20) who received PCEA using a standard electronic device. Efficacy, as assessed by visual analogue scores, was comparable to that achieved in the control group. Patient and nursing satisfaction was high and similar to that in the control group. There was a low incidence of side-effects with both devices. Patients using the disposable device used less pethidine than patients using the electronic device (median (interquartile range) 181 (100-275) mg versus 238 (213-375) mg; p = 0.035). Use of this disposable device is an acceptable alternative to more expensive and bulkier electronic devices for PCEA after Caesarean section.

Adult↗