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Tony Gin

Publications and source records attributed to Tony Gin.

At least 19 recordsLinked to original sources
PubMed2006

Publication bias affected the estimate of postoperative nausea in an acupoint stimulation systematic review.

BACKGROUND AND OBJECTIVE: To assess the effect of publication bias and country effect on the results and conclusion of a systematic review of wrist P6 acupoint stimulation for the prevention of postoperative nausea and vomiting. METHODS: Reanalysis of a systematic review of 26 randomized trials comparing P6 acupoint stimulation with sham published in the Cochrane Database of Systematic Reviews using the Copas' sensitivity approach. RESULTS: If it is assumed that all studies that have ever been carried out are included, or that those selected for review are truly representative of all such studies, then the estimated relative risk (RR) for nausea was 0.71 (95% CI: 0.58 to 0.88, P<.01) and for vomiting was 0.70 (95% CI: 0.56 to 0.88, P<.01) after adjusting for country effect. For nausea, adjustment for publication bias suggests that the risk has been overestimated. If around 33% of studies have been unpublished, the RR of nausea (0.92, 95% CI: 0.80 to 1.06, P=.25) is no longer significant. For vomiting, however, there is no strong evidence of publication bias. The number of unpublished studies required to substantially overturn the above significant result is implausibly large. CONCLUSION: Publication bias affects the published estimate of postoperative nausea, not vomiting.

Humans↗
PubMed2006

Incidence and risk of adverse perioperative events among surgical patients taking traditional Chinese herbal medicines.

BACKGROUND: The use of traditional Chinese herbal medicines (TCHMs) among the presurgical population is widespread, but their impact on perioperative patient care is unclear. The authors estimated the incidence and risk of TCHM-related perioperative events. METHODS: In a Hong Kong cohort study, 601 patients undergoing major elective surgery were asked about their Western medicine and TCHM use in the 2 weeks before surgery. Unanticipated perioperative events were noted by attending anesthesiologists, blinded to patients' use of specific TCHMs. Modified Poisson regression models were used to obtain the relative risk of combined endpoints of perioperative events associated with TCHM use. RESULTS: Of the 601 patients, 483 patients (80%) took self-prescribed TCHM, and 47 (8%) took TCHM by prescription (with or without self-prescribed TCHM) in the 2 weeks before surgery. The crude incidences of any combined endpoints of preoperative, intraoperative, and postoperative events were 23% (95% confidence interval, 19-26%), 74% (95% confidence interval, 71-78%), and 63% (95% confidence interval, 59-66%), respectively. Compared with nonusers, patients who took TCHM by prescription were more likely to have a preoperative event (adjusted relative risk, 2.21; 95% confidence interval, 1.14-4.29). The authors present four case reports to highlight the effect of TCHM by prescription on prolonged activated partial thromboplastin time and hypokalemia in the preoperative period. In contrast, there was no significant association between the use of any type of TCHM and the occurrence of either intraoperative or postoperative events. CONCLUSIONS: The use of TCHM by prescription near the time of surgery should be discouraged because of the increased risk of adverse events in the preoperative period.

Adolescent↗
PubMed2006

Alfentanil dosage when inserting the classic laryngeal mask airway.

BACKGROUND: The purpose of this study was to determine an optimum dose of alfentanil, coadministered with 2.5 mg/kg propofol, when inserting a classic laryngeal mask airway. METHODS: Seventy-five adult ethnic Chinese patients with an American Society of Anesthesiologists physiologic status classification I or II and requiring anesthesia for minor surgery with a laryngeal mask were recruited. They were randomly assigned to five dosage groups: placebo or 5, 10, 15, or 20 microg/kg. The study drug plus propofol were administered, and 90 s later, insertion conditions were assessed using a six-category score. The duration of apnea was recorded. A probit analysis was performed and used to estimate the ED50 and ED95 with 95% confidence intervals for each assessment. RESULTS: Twenty-five male and 50 female patients, aged 18-59 yr, were studied. The five groups were similar. Laryngeal mask insertion was successful in all but one alfentanil patient. Duration of apnea increased with increasing dosage of alfentanil to over 5 min (P < 0.001). Dose-responses could not be predicted for categories of resistance to mouth opening and to insertion. For the other four categories, swallowing, gagging, movement, and laryngospasm, ED50 and ED95 with confidence intervals for alfentanil could be determined. CONCLUSION: The optimum dose for alfentanil, when coadministered with 2.5 mg/kg propofol, was 10 microg/kg.

Adolescent↗
PubMed2006

Intravenous magnesium sulfate after aneurysmal subarachnoid hemorrhage: a prospective randomized pilot study.

We performed a randomized, double-blind, pilot study on magnesium sulfate (MgSO4) infusion for aneurysmal subarachnoid hemorrhage (SAH).Sixty patients with SAH were randomly allocated to receive either MgSO4 80 mmol/day or saline infusion for 14 days. Patients also received intravenous nimodipine. Episodes of vasospasm were treated with hypertensive and hypervolemic therapy. Neurologic status was assessed 6 months after hemorrhage using the Barthel index and Glasgow Outcome Scale. Incidences of cardiac and pulmonary complications were also recorded. Patient characteristics, severity of SAH, and surgical treatment did not differ between groups. The incidence of symptomatic vasospasm decreased from 43% in the saline group to 23% in patients receiving MgSO4 infusion, but it did not reach statistical significance, P=0.06. For patients who had transcranial Doppler-detected vasospasm, defined as mean flow velocity >120 cm/s and a Lindegaard index >3, the duration was shorter in the magnesium group compared with controls (P<0.01). There was, however, no difference between groups in functional recovery or Glasgow Outcome Scale score. The incidence of adverse events such as brain swelling, hydrocephalus, and nosocomial infection was also similar in patients receiving MgSO4 or saline. In this small pilot study, MgSO4 infusion for aneurysmal SAH is feasible. On the basis of the preliminary data, a larger study recruiting approximately 800 patients is required to test for a possible neuroprotective effect of magnesium after SAH.

Acute Disease↗
PubMed2006

Magnesium therapy within 48 hours of an aneurysmal subarachnoid hemorrhage: neuro-panacea.

Whereas advances in neurosurgical treatment and intensive care management improve the results from many of the devastating complications associated with aneurysmal subarachnoid hemorrhage, cerebral vasospasm remains a major cause of neurological morbidity and mortality. Experimental studies suggested that MgSO(4) inhibits excitatory amino acid release, blocks N-methyl-D-aspartate (NMDA) receptors and prevents calcium entry into the cell. Magnesium also increases red blood cell deformability. These changes may reduce the occurrence of cerebral vasospasm and minimize neuronal injury during episodes of cerebral vasospasm. Our group is currently hosting the intravenous magnesium sulfate to improve outcome after aneurysmal subarachnoid hemorrhage (IMASH) trial, which is a randomized, placebo-controlled, double-blinded, multicentered trial to evaluate the effect of magnesium sulfate infusion on the clinical outcome of patients with aneurysmal subarachnoid hemorrhage since 2002. The pilot result showed a trend towards decreased clinical vasospasm and better patient outcome. Magnesium sulfate infusion may prove to be an effective and inexpensive way to reduce the morbidity and mortality associated with aneurysmal subarachnoid hemorrhage, which is a major breakthrough in the current management.

Calcium Channel Blockers↗
PubMed2006

A systematic review (meta-analysis) of the accuracy of the Mallampati tests to predict the difficult airway.

The original and modified Mallampati tests are commonly used to predict the difficult airway, but there is controversy regarding their accuracy. We searched MEDLINE and other databases for prospective studies of patients undergoing general anesthesia in which the results of a preoperative Mallampati test were compared with the subsequent rate of difficult airway (difficult laryngoscopy, difficult intubation, or difficult ventilation as reference tests). Forty-two studies enrolling 34,513 patients were included. The definitions of the reference tests varied widely. For predicting difficult laryngoscopy, both versions of the Mallampati test had good accuracy (area under the summary receiver operating characteristic (sROC) curve = 0.89 +/- 0.05 and 0.78 +/- 0.05, respectively). For predicting difficult intubation, the modified Mallampati test had good accuracy (area under the sROC curve = 0.83 +/- 0.03) whereas the original Mallampati test was poor (area under the sROC curve = 0.58 +/- 0.12). The Mallampati tests were poor at identifying difficult mask ventilation. Publication bias was not detected. Used alone, the Mallampati tests have limited accuracy for predicting the difficult airway and thus are not useful screening tests.

Anesthesia, General↗
PubMed2006

The additive interactions between ondansetron and droperidol for preventing postoperative nausea and vomiting.

Prophylactic ondansetron or droperidol reduces the incidence of postoperative nausea and vomiting (PONV). Previous studies showed that the combination of these two drugs produced better antiemetic effect than either drug alone. We present a nonparametric method to determine the pharmacologic interaction between ondansetron and droperidol and compared the observed response of the drug combination with that predicted from additivity. This is calculated as the product of the individual drug response, normalized to that of the controls. Five minutes before induction of anesthesia, 400 patients scheduled for laparoscopic gynecologic surgery were randomly assigned to receive 1) saline IV; 2) ondansetron 4 mg IV; 3) droperidol 1.25 mg IV; or 4) a combination of droperiodol 1.25 mg and ondansetron 4 mg IV. A standardized anesthetic technique and postoperative analgesic regimen were used. Patients were reviewed regularly for 48 h. Changes in the heart rate adjusted QT (QTc) interval were measured from electrocardiograms recorded before and 5 min after study drug administration. In a subgroup of 160 patients, QTc intervals were measured again at 2-3 h after surgery. During the first 48 h after the surgery, the proportion of patients experiencing PONV was 68% (95% CI 58-77) in the control group. A single dose of ondansetron or droperidol decreased the incidence of PONV to 30% (95% CI 21-40) and 28% (95% CI 20-38), respectively. The predicted incidence of PONV after drug combination, 11.8% (7.1-11.9), was similar to that observed, 12.1% (6.4-20.2), P = 0.94. The corresponding predicted and observed treatment responses in the combination group were 88.2% and 87.9%, respectively. There was a modest and transient increase in QTc interval after administration of ondansetron, droperidol, or their combination. The changes were however similar among groups. We conclude that the interaction between ondansetron and droperiodol was additive. Both drugs acted independently of each other through their specific mechanisms of action. The incidence of QTc prolongation did not increase with the drug combination.

Adolescent↗
PubMed2005

Arterial and venous pharmacokinetics of ropivacaine with and without epinephrine after thoracic paravertebral block.

BACKGROUND: Animal and volunteer studies indicate that ropivacaine is associated with less neurologic and cardiac toxicity than bupivacaine. Ropivacaine may offer advantages when used for thoracic paravertebral block. This study was designed to describe the pharmacokinetics of ropivacaine after thoracic paravertebral block. METHODS: Twenty female patients undergoing elective unilateral breast surgery were randomly assigned to receive a single bolus thoracic paravertebral injection of 2 mg/kg ropivacaine, with or without 5 mug/ml epinephrine. Simultaneous arterial and venous blood samples were obtained for plasma ropivacaine assay. Data were analyzed with NONMEM, using two possible absorption models: conventional first-order absorption and absorption following the inverse gaussian density function. RESULTS: Epinephrine reduced the peak plasma concentrations and delayed the time of peak concentration of ropivacaine in both the arterial and venous blood. The time course of drug input into the systemic circulation was best described by two inverse gaussian density functions. The median bioavailability of the rapid component was approximately 20% higher when epinephrine was not used. The mean absorption times were 7.8 min for the rapid absorption phase and 697 min for the slow absorption phase, with wide dispersion of the absorption function for the acute phase. The half-time of arterial-venous equilibration was 1.5 min. CONCLUSION: The absorption of ropivacaine after thoracic paravertebral block is described by rapid and slow absorption phases. The rapid phase approximates the speed of intravenous administration and accounts for nearly half of ropivacaine absorption. The addition of 5 mug/ml epinephrine to ropivacaine significantly delays its systemic absorption and reduces the peak plasma concentration.

Absorption↗
PubMed2005

Educating patients about anaesthesia: effect of various modes on patients' knowledge, anxiety and satisfaction.

PURPOSE OF REVIEW: This review summarizes the current research on the effects of preoperative education about anaesthesia on patient knowledge, anxiety, and satisfaction. RECENT FINDINGS: Misconceptions about the process and the risks of general and regional anaesthesia are common. Information leaflets should be formally assessed to ensure that patient knowledge is increased. Patients should be surveyed to see what information they want, rather than just providing what healthcare professionals think is appropriate. The amount of information requested by patients can vary considerably. Providing detailed drug information leaflets for anaesthetic drugs was not thought necessary by many patients, but was not associated with increased preoperative state anxiety. Information sessions to small groups of patients by multidisciplinary healthcare professionals were useful for patients undergoing total hip arthroplasty, with a small reduction in preoperative state anxiety, but patient satisfaction levels remained unchanged. Patient satisfaction should be measured by a valid and reliable questionnaire. When this was done, the introduction of pamphlets did not improve patient satisfaction. The evidence for better patient outcomes after patient education interventions is not convincing. SUMMARY: Preoperative patient education should recognize that different patients have various misconceptions, expectations and needs. Multiple modes may be required to increase knowledge for informed consent and decrease patient anxiety. Patient satisfaction is generally high irrespective of the mode of patient education.

Journal Article↗
PubMed2005

A comparison of patients' and health care professionals' preferences for symptoms during immediate postoperative recovery and the management of postoperative nausea and vomiting.

In this study we sought to examine the differences in patients' and health care professionals' preferences for symptoms during immediate postoperative recovery and the management of postoperative nausea and vomiting (PONV). The key differences between symptoms during immediate postoperative recovery (PONV, sedation, and pain) and management of PONV (prophylaxis, efficacy of antiemetic, and extra cost) were used to develop 14 scenarios in a questionnaire. Fifty-two health care professionals (anesthesiologists and recovery room nurses) and 200 women undergoing elective gynecological surgery were recruited (overall response rate, 97%). From patients' and health care professionals' perspectives, conjoint analysis showed that the most important attribute for immediate postoperative recovery was a reduction in the risk of PONV. Health care professionals placed more importance on postoperative sedation than patients did. They were more concerned about the cost of the antiemetic to the patient than the patients were themselves. There was no preference for a policy of effective treatment versus routine prophylaxis. This study shows that there were small differences in the importance of pain, sedation, efficacy of the antiemetic, and extra cost of treatment between patients and health care professionals.

Adult↗
PubMed2004

Possible interaction between sevoflurane and Aloe vera.

OBJECTIVE: To describe a patient with massive intraoperative bleeding after oral consumption of Aloe vera tablets. CASE SUMMARY: A 35-year-old woman lost 5 L of blood during surgery as a result of a possible herb-drug interaction between Aloe vera and sevoflurane. DISCUSSION: Aloe vera is a common herb used for antiinflammatory and antiarthritic activity, as well as antibacterial, hypoglycemic, and lipid-lowering effects. Compounds contained within Aloe vera can cause a reduction in prostaglandin synthesis, which may inhibit secondary aggregation of platelets. Sevoflurane inhibits thromboxane A(2) formation by suppression of cyclooxygenase activity, impairs platelet aggregation, and prolongs bleeding. Although the vascularity and size of the hemangioma were the most important factors for the massive intraoperative blood loss, concomitant use of sevoflurane and Aloe vera played a contributory role. An objective causality assessment revealed that this adverse event was possible as a result of the sevoflurane and Aloe vera interaction. CONCLUSIONS: There is a potential herb-drug interaction between Aloe vera and sevoflurane based on the antiplatelet effects of these 2 agents. Herbal medications with antiplatelet potential should be discontinued before anesthesia and surgery.

Adult↗
PubMed2004

Interventional neurophysiologic monitoring.

PURPOSE OF REVIEW: Intraoperative neurophysiologic monitoring provides useful information on the functional status of the nervous system. This review focuses on recently published data concerning the impact of monitoring on patient outcome. RECENT FINDINGS: There is level I evidence to support the use of bispectral index monitoring to prevent awareness during anesthesia in high-risk patients. A number of randomized trials have shown that monitoring-guided anesthesia using the bispectral index or other devices will expedite recovery and improve perioperative drug utilization. There are also preliminary reports suggesting that anesthesia dictated by bispectral index monitoring may alter long-term outcome and reduce mortality. In surgical procedures, however, it is less clear whether neurophysiologic monitoring will improve patient outcome. Currently, the majority of data are derived from respective case series. Nonetheless, monitoring with somatosensory evoked potential has been shown to reduce postoperative neurologic deficits after spinal surgery. There is also evidence to suggest that electromyography and motor evoked potential are essential complements to somatosensory evoked potential for monitoring of spinal cord surgery. SUMMARY: Brain monitoring facilitates anesthetic drug administration. An increasing number of neurosurgical procedures will require some form of intraoperative neurophysiologic monitoring to achieve higher degrees of safety and accuracy. In many instances, the data derived from monitoring will guide and influence surgical decisions. In this context, neurophysiologic monitoring should be regarded as interventional.

Journal Article↗
PubMed2004

A dose-response meta-analysis of prophylactic intravenous ephedrine for the prevention of hypotension during spinal anesthesia for elective cesarean delivery.

UNLABELLED: We systematically reviewed available studies to determine the dose-response characteristics of prophylactic i.v. ephedrine for the prevention of hypotension during spinal anesthesia for cesarean delivery. We searched for randomized controlled trials (RCTs) or cohort studies-obtained through MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and reference lists of published articles-in which two or more different doses of prophylactic i.v. ephedrine were used to prevent hypotension during spinal anesthesia for cesarean delivery. Four RCTs and one cohort study were found (total n = 390). There was a significant dose-response relationship in the RCTs pooled for hypotension (slope = -0.0128; 95% confidence interval [CI], -0.0213 to -0.0044), hypertension (slope = 0.0563; 95% CI, 0.0235 to 0.0892), and umbilical arterial pH (slope = -0.03; 95% CI, -0.05 to 0.00). The efficacy of ephedrine for preventing hypotension was small. At 14 mg, the number-needed-to-treat was only 7.6 (95% CI, 4.8-21.1), and this was the same as the number-needed-to-harm (7.6; 95% CI, 3.7-23.4). At larger doses, the likelihood of causing hypertension was actually more than that of preventing hypotension, and there was also a minor decrease in umbilical arterial pH. IMPLICATIONS: The authors performed a systematic review of dose-response studies of i.v. bolus ephedrine for preventing hypotension during spinal anesthesia for cesarean delivery. Prophylactic ephedrine cannot be recommended. The efficacy is poor at smaller doses, whereas at larger doses, the likelihood of causing hypertension is actually more than that of preventing hypotension.

Adult↗
PubMed2004

Preoperative ketamine improves postoperative analgesia after gynecologic laparoscopic surgery.

UNLABELLED: In this study, we evaluated the preemptive effect of a small dose of ketamine on postoperative wound pain. In a randomized, double-blinded, controlled trial, we compared the analgesic requirement in patients receiving preincision ketamine with ketamine after skin closure or placebo after gynecologic laparoscopic surgery. One-hundred-thirty-five patients were randomly assigned to receive preincision or postoperative ketamine 0.15 mg/kg or saline IV. Anesthetic technique was standardized. Patients were interviewed regularly up to 4 wk after surgery. Pain score, morphine consumption, side effects, and quality of recovery score were recorded. Patients receiving preincision ketamine had a lower pain score in the first 6 h after operation compared with the postoperative (P = 0.001) or placebo groups (P < 0.001). The mean (95% confidence intervals) time to first request for analgesia in the preincision group, 1.8 h (1.4-2.1), was longer than the postoperative group, 1.2 h (0.9-1.5; P < 0.001), or the placebo group, 0.7 h (0.4-0.9; P < 0.001). The mean +/- SD morphine consumption in the preincision group, 1.5 +/- 2.0 mg, was less than that in the postoperative group, 2.9 +/- 3.1 mg (P = 0.04) and the placebo group, 3.4 +/- 2.7 mg (P = 0.003). There was no significant difference among groups with respect to hemodynamic variables or side effects. No patient complained of hallucinations or nightmares. We conclude that a small dose of ketamine is not only safe, but it also provides preemptive analgesia in patients undergoing gynecologic laparoscopic surgery. IMPLICATIONS: In women undergoing laparoscopic gynecologic surgery, a small preoperative dose of ketamine (0.15 mg/kg) produced preemptive analgesia. There were no significant hemodynamic and psychological side effects with this dose.

Adult↗
PubMed2003

Educating patients about anesthesia: a systematic review of randomized controlled trials of media-based interventions.

UNLABELLED: In this systematic review, we compared the effectiveness of media-based patient education about anesthesia. Fifteen randomized controlled trials (n = 1506) were identified after a systematic search of electronic databases (MEDLINE, EMBASE, CINAHL, PSYCINFO, The Cochrane Controlled Trials Registry), published articles, and contact with authors. Outcomes assessed were anxiety, knowledge, and patient satisfaction. Anxiety levels before anesthesia were less intense in subjects receiving the video and printed information compared with those receiving no intervention (weighted mean difference of 3; 95% confidence interval [95%CI], 1-5 Spielberger's State and Trait Anxiety Inventory). Patients in the video group were more likely to answer all knowledge questions correctly compared with patients with no intervention (relative risk of 6.64; 95%CI, 2.05-21.52). The level of knowledge about pain management was higher in the video group compared with patients with no intervention (weighted mean difference of 17%; 95%CI, 9-25). However, the level of patient satisfaction with the intervention (expectation versus actual anesthetic experience) was similar between the groups (relative risk of 1.06; 95%CI, 0.93-1.22). This systematic review supports the use of video and printed information about general process and risks of anesthesia for patient education before surgery. IMPLICATIONS: The effectiveness of media-based interventions for educating patients about general process and risks of anesthesia were compared in this systematic review. The use of video and/or printed information can decrease patient anxiety and increase patient knowledge. However, patient satisfaction was similar between media-based intervention and nonintervention groups.

Adult↗