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Biomedical subjects

Anna Lee

Publications and source records attributed to Anna Lee.

At least 19 recordsLinked to original sources
PubMed2007

Cesarean delivery or vaginal birth: a survey of patient and clinician thresholds.

OBJECTIVE: To estimate what level of additional fetal risk women and their caregivers in late pregnancy considered acceptable to avoid a cesarean and achieve a vaginal birth. METHODS: Six hundred women in late pregnancy and 294 obstetric consultants, registrars, midwives, and medical students were recruited to the study. With the assistance of a visual probability aid representing 10,000 births, they were asked to consider what level of fetal risk of death or serious disability they would consider acceptable to avoid cesarean and achieve vaginal birth. RESULTS: The median level of fetal risk deemed acceptable to achieve a vaginal birth for pregnant women was 10 per 10,000 births (95% confidence interval [CI] 10-13 per 10,000), although the range of responses was wide (1-5,000 per 10,000). Among staff, the median level of acceptable fetal risk was 13 per 10,000 births (95% CI 10-20 per 10,000). Women participating in lower intervention models of care, such as the birth center or team midwifery, were more tolerant of fetal risk (odds ratios [ORs] 2.1, 95% CI 1.6-2.9 and 1.5, 95% CI 1.0-2.3, for accepting a fetal risk of 20 per 10,000 or greater), whereas women with a complicated pregnancy were less tolerant of fetal risk (OR 0.7, 95% CI 0.5-0.9). CONCLUSION: Pregnant women and their caregivers have a low tolerance for fetal risk associated with vaginal birth. This study demonstrates the difficulty of minimizing obstetric intervention rates in the face of high expectations for fetal outcome. Obstetric and demographic factors were found to significantly impact the "acceptable fetal risk" threshold, which highlights the importance of individualized counseling regarding mode of birth. LEVEL OF EVIDENCE: III.

Attitude of Health Personnel↗
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

Acupuncture and anaesthesia.

Acupuncture and related techniques are increasingly practised in anaesthesia. This paper reviews the current evidence and applicability of acupuncture and related techniques for anaesthetic procedures and postoperative nausea and vomiting. Recent evidence suggests that manual acupuncture is effective for reducing preoperative anxiety and for postoperative pain relief. Current available data do not support the use of acupuncture as an adjunct to the general anaesthetic in the intraoperative setting. There are extensive and good quality data to support the use of P6 acupoint stimulation techniques for preventing postoperative nausea and vomiting in combination with or as an alternative to conventional anti-emetics. The use of acupuncture for labour pain management appears promising but requires further research. Patient selection, acupoint selection, needling techniques, and mode of acupuncture need to be considered when applying acupuncture and related techniques in the perioperative setting. There are guidelines for the conduct and reporting of acupuncture research, and these should be followed to improve the quality of studies.

Acupuncture Therapy↗
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

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↗
PubMed2005

Increased pulmonary responses to acute ozone exposure in obese db/db mice.

Epidemiological studies indicate the incidence of asthma is increased in obese and overweight humans. Responses to ozone (O(3)), an asthma trigger, are increased in obese (ob/ob) mice lacking the satiety hormone leptin. The long form of leptin receptor (Ob-R(b)) is required for satiety; mice lacking this receptor (db/db mice) are also substantially obese. Here, wild-type (WT) and db/db mice were exposed to air or O(3) (2 ppm) for 3 h. Airway responsiveness, measured by the forced oscillation technique, was greater in db/db than WT mice after air exposure. O(3)-induced increases in pulmonary resistance and airway responsiveness were also greater in db/db mice. BALF eotaxin, IL-6, KC, and MIP-2 increased 4 h after O(3) exposure and subsided by 24 h, whereas protein and neutrophils continued to increase through 24 h. For each outcome, the effect of O(3) was significantly greater in db/db than WT mice. Previously published results obtained in ob/ob mice were similar except for O(3)-induced neutrophils and MIP-2, which were not different from WT mice. O(3) also induced pulmonary IL-1beta and TNF-alpha mRNA expression in db/db but not ob/ob mice. Leptin was increased in serum of db/db mice, and pulmonary mRNA expression of short form of leptin receptor (Ob-R(a)) was similar in db/db and WT mice. These data confirm obese mice have innate airway hyperresponsiveness and increased pulmonary responses to O(3). Differences between ob/ob mice, which lack leptin, and db/db mice, which lack Ob-R(b) but not Ob-R(a), suggest leptin, acting through Ob-R(a), can modify some pulmonary responses to O(3).

Animals↗
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

An assessment of the telehealth needs and health-care priorities of Tanna Island: a remote, under-served and vulnerable population.

We surveyed eight Canadian physicians who had each provided medical care for six months on the remote and under-served island of Tanna in Vanuatu. The most frequently encountered medical problems on Tanna were infectious diseases (tuberculosis, hepatitis, abscesses, malaria, pneumonia, typhoid fever, meningitis and skin infections). When physicians were asked about the top three health-care priorities, they ranked tuberculosis control, clean water and improved health-care delivery/communication between hospital and outposts as most important. The key issues were: (1) basic public health needs and infrastructure development are higher in priority than telehealth; (2) telehealth consultants must have knowledge pertinent to local conditions and resources available to the population; (3) electronic equipment suited to tropical environments is needed; (4) projects must be developed locally rather than internationally. Understanding how telehealth can provide support to health professionals under challenging conditions may assist with the health priorities in developing countries and potentially provide access to resources both locally and internationally.

Developing Countries↗
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↗
PubMed2005

Testing the reliability of a new ultrasonic cardiac output monitor, the USCOM, by using aortic flowprobes in anesthetized dogs.

We have used an animal model to test the reliability of a new portable continuous-wave Doppler ultrasonic cardiac output monitor, the USCOM. In six anesthetized dogs, cardiac output was measured with a high-precision transit time ultrasonic flowprobe placed on the ascending aorta. The dogs' cardiac output was increased with a dopamine infusion (0-15 microg x kg(-1) x min(-1)). Simultaneous flowprobe and USCOM cardiac output measurements were made. Up to 64 pairs of readings were collected from each dog. Data were compared by using the Bland and Altman plot method and Lin's concordance correlation coefficient. A total of 319 sets of paired readings were collected. The mean (+/-sd) cardiac output was 2.62 +/- 1.04 L/min, and readings ranged from 0.79 to 5.73 L/min. The mean bias between the 2 sets of readings was -0.0l L/min, with limits of agreement (95% confidence intervals) of -0.34 to 0.31 L/min. This represents a +/-13% error. In five of six dogs, there was a high degree of concordance, or agreement, between the 2 methods, with coefficients >0.9. The USCOM provided reliable measurements of cardiac output over a wide range of values. Clinical trials are needed to validate the device in humans.

Animals↗
PubMed2005

E-health and the Universitas 21 organization: 3. Global policy.

There is an urgent need to develop global e-health policy in order both to facilitate and to manage the potential of e-health. As part of the Universitas 21 (U21) project in e-health, an evaluation of the status of global e-health policy was performed using a SWOT analysis (strengths, weaknesses, opportunities and threats). The analysis showed that the greatest threat to global e-health policy is the autonomous nature of domestic health-care systems. The greatest opportunity may be the prospect for nations and individuals to work together in establishing mechanisms necessary to offer health-care access through global e-health--a new 'global public good'. Full integration of e-health into existing health-care systems could be achieved in both a practical and a policy sense through global e-health policy initiatives that facilitate integration across jurisdictions. There is a pressing need to resolve a range of e-health policy issues, and a concomitant need for research that will inform and support the process. A process that adopts a global approach is recommended.

Attitude to Health↗
PubMed2004

Insulin resistance in the skeletal muscle of women with PCOS involves intrinsic and acquired defects in insulin signaling.

Insulin resistance in polycystic ovary syndrome (PCOS) is due to a postbinding defect in signaling that persists in cultured skin fibroblasts and is associated with constitutive serine phosphorylation of the insulin receptor (IR). Cultured skeletal muscle from obese women with PCOS and age- and body mass index-matched control women (n = 10/group) was studied to determine whether signaling defects observed in this tissue in vivo were intrinsic or acquired. Basal and insulin-stimulated glucose transport and GLUT1 abundance were significantly increased in cultured myotubes from women with PCOS. Neither IR beta-subunit abundance and tyrosine autophosphorylation nor insulin receptor substrate (IRS)-1-associated phosphatidylinositol (PI) 3-kinase activity differed in the two groups. However, IRS-1 protein abundance was significantly increased in PCOS, resulting in significantly decreased PI 3-kinase activity when normalized for IRS-1. Phosphorylation of IRS-1 on Ser312, a key regulatory site, was significantly increased in PCOS, which may have contributed to this signaling defect. Insulin signaling via IRS-2 was also decreased in myotubes from women with PCOS. In summary, decreased insulin-stimulated glucose uptake in PCOS skeletal muscle in vivo is an acquired defect. Nevertheless, there are intrinsic abnormalities in glucose transport and insulin signaling in myotubes from affected women, including increased phosphorylation of IRS-1 Ser312, that may confer increased susceptibility to insulin resistance-inducing factors in the in vivo environment. These abnormalities differ from those reported in other insulin resistant states consistent with the hypothesis that PCOS is a genetically unique disorder conferring an increased risk for type 2 diabetes.

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

AMP-kinase regulates food intake by responding to hormonal and nutrient signals in the hypothalamus.

Obesity is an epidemic in Western society, and causes rapidly accelerating rates of type 2 diabetes and cardiovascular disease. The evolutionarily conserved serine/threonine kinase, AMP-activated protein kinase (AMPK), functions as a 'fuel gauge' to monitor cellular energy status. We investigated the potential role of AMPK in the hypothalamus in the regulation of food intake. Here we report that AMPK activity is inhibited in arcuate and paraventricular hypothalamus (PVH) by the anorexigenic hormone leptin, and in multiple hypothalamic regions by insulin, high glucose and refeeding. A melanocortin receptor agonist, a potent anorexigen, decreases AMPK activity in PVH, whereas agouti-related protein, an orexigen, increases AMPK activity. Melanocortin receptor signalling is required for leptin and refeeding effects on AMPK in PVH. Dominant negative AMPK expression in the hypothalamus is sufficient to reduce food intake and body weight, whereas constitutively active AMPK increases both. Alterations of hypothalamic AMPK activity augment changes in arcuate neuropeptide expression induced by fasting and feeding. Furthermore, inhibition of hypothalamic AMPK is necessary for leptin's effects on food intake and body weight, as constitutively active AMPK blocks these effects. Thus, hypothalamic AMPK plays a critical role in hormonal and nutrient-derived anorexigenic and orexigenic signals and in energy balance.

Adenylate Kinase↗
PubMed2004

Practicality of performing medical procedures in chemical protective ensembles.

OBJECTIVE: To determine whether certain life saving medical procedures can be successfully performed while wearing different levels of personal protective equipment (PPE), and whether these procedures can be performed in a clinically useful time frame. METHODS: We assessed the capability of eight medical personnel to perform airway maintenance and antidote administration procedures on manikins, in all four described levels of PPE. The levels are: Level A--a fully encapsulated chemically resistant suit; Level B--a chemically resistant suit, gloves and boots with a full-faced positive pressure supplied air respirator; Level C--a chemically resistant splash suit, boots and gloves with an air-purifying positive or negative pressure respirator; Level D--a work uniform. Time in seconds to inflate the lungs of the manikin with bag-valve-mask, laryngeal mask airway (LMA) and endotracheal tube (ETT) were determined, as was the time to secure LMAs and ETTs with either tape or linen ties. Time to insert a cannula in a manikin was also determined. RESULTS: There was a significant difference in time taken to perform procedures in differing levels of personal protective equipment (F21,72 = 1.75, P = 0.04). Significant differences were found in: time to lung inflation using an endotracheal tube (A vs. C mean difference and standard error 75.6 +/- 23.9 s, P = 0.03; A vs. D mean difference and standard error 78.6 +/- 23.9 s, P = 0.03); time to insert a cannula (A vs. D mean difference and standard error 63.6 +/- 11.1 s, P < 0.001; C vs. D mean difference and standard error 40.0 +/- 11.1 s, P = 0.01). CONCLUSIONS: A significantly greater time to complete procedures was documented in Level A PPE (fully encapsulated suits) compared with Levels C and D. There was however, no significant difference in times between Level B and Level C. The common practice of equipping hospital and medical staff with only Level C protection should be re-evaluated.

Antidotes↗
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↗