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Biomedical subjects

Paul S Myles

Publications and source records attributed to Paul S Myles.

At least 19 recordsLinked to original sources
PubMed2007

Integrating incident reporting into an electronic patient record system.

Developments in information technology offer new opportunities to design electronic patient record systems (EPR) which integrate a broad range of functions such as clinical decision support, order entry, or electronic alerts. It has been recently suggested that EPR could support new applications for disease surveillance and patient safety. We describe the integration of a voluntary incident reporting system into an EPR used in operating theatres, to allow the reporting of accidents and preventable complications. We assessed system's reliability and users' acceptance. During the 4-years observation period (2002-2006), 48,983 interventional procedures were performed. Clinicians documented 85.1% of procedures on the incident reporting form. Agreement between chart review and electronically reported incidents was 80.6%. The integration of an incident reporting system into an EPR is reliable and well supported by health care professionals.

Adult↗
PubMed2007

Lung transplantation.

PURPOSE OF REVIEW: To describe recent advances in lung transplantation relevant to anesthesiologists. RECENT FINDINGS: There is recent literature describing medical, surgical, anesthetic and critical care of lung transplant recipients. SUMMARY: There have been substantial changes in preoperative selection and preparation of lung transplant recipients; these include donation after cardiac death, and improved lung-preservation solutions. Newer immunosuppression regimens have been successfully evaluated in clinical trials. Particular advances in anesthesia include endorsement of fluid restriction in thoracic surgery, greater use of transesophageal echocardiography, and postoperative extracorporeal membrane oxygenation.

Anesthesia↗
PubMed2006

Preoperative folate and homocysteine status in patients undergoing major surgery.

BACKGROUND & AIMS: Patients with folate deficiency and elevated homocysteine (Hcy) levels have increased risk of cerebrovascular and cardiovascular disease. They may also be at increased risk of complications after surgery because nitrous oxide interferes with folate metabolism. The aim of this study was to assess the incidence of folate deficiency and hyperhomocysteinemia in patients presenting for major surgery. We also tested the utility of a brief preoperative medical and dietary questionnaire to identify those with low folate or elevated Hcy levels. METHODS: We enrolled 390 patients and obtained a preoperative fasting blood sample from each of the study participants (folate [n=386], homocysteine [n=387]). RESULTS: Although only one patient had folate deficiency preoperatively (incidence +/-SD folate and Hcy concentrations were 23.7+/-5.2 nmol/l and 9.4+/-4.2 micromol/l, respectively. There was a negative correlation between folate and Hcy, r=-0.27, P<0.001. Multivariate analyses indicated that vegan status and folate supplementation prevented low folate status (P<0.05), while age of the patient, and history of heart failure and anaemia predicted elevated Hcy concentration. CONCLUSIONS: Some factors identified by a brief medical and dietary questionnaire are associated with folate and homocysteine status. Hyperhomocysteinaemia occurs in about 7.5% of surgical patients; however, both low folate status and elevated Hcy concentration are less likely in those taking folate or vitamin B supplements. This has implications for patients undergoing nitrous oxide anaesthesia because of its inhibition of folate metabolism, and should prompt clinicians to consider folate and other nutritional supplementation before elective surgery.

Anesthetics, Inhalation↗
PubMed2006

A comparison of the effect of high- and low-dose fentanyl on the incidence of postoperative cognitive dysfunction after coronary artery bypass surgery in the elderly.

BACKGROUND: Postoperative cognitive dysfunction (POCD) after coronary artery bypass graft surgery is a common complication for which, despite many clinical investigations, no definitive etiology has been found. The current use of both high- and low-dose fentanyl as anesthetic techniques allowed us to investigate the effect of fentanyl on the incidence of POCD. METHODS: Three hundred fifty patients scheduled to undergo elective coronary artery bypass graft surgery were randomized to receive either high-dose fentanyl (50 microg/kg) or low-dose fentanyl (10 mug/kg) as the basis of the anesthetic. All patients underwent neuropsychological testing before surgery and at 1 week, 3 months, and 12 months after surgery. RESULTS: One hundred sixty-eight patients in the low-dose group and 158 patients in the high-dose group were included in the final analysis. Neuropsychological testing was performed on 88%, 93%, and 92% of patients at 1 week, 3 months, and 12 months, respectively. There was no difference between group mean scores at any of the three testing times. Analysis of individual patients by the 20% rule did not detect any differences between groups. The one SD rule, which has fewer false-positive results, detected significantly more patients with POCD in the low-dose group than in the high-dose group at 1 week (23.6% vs. 13.7%; P = 0.03) but not at the other testing times. Patients with POCD spent an average of 1.2 days longer in the hospital than those without POCD (P = 0.021). CONCLUSIONS: High-dose fentanyl is not associated with a difference in the incidence of POCD at 3 or 12 months after surgery. Low-dose fentanyl leads to shorter postoperative ventilation times and may be associated with a greater incidence of POCD 1 week after surgery. Early POCD is associated with an increased duration of stay in the hospital.

Aged↗
PubMed2006

Gender and recovery after general anesthesia combined with neuromuscular blocking drugs.

Previous studies suggest that women recover faster from general anesthesia than men, but it is unclear whether this is a result of a gender effect or differences in the pattern of drug administration or type of surgery. We performed a subset analysis comparing recovery characteristics from general anesthesia combined with neuromuscular blocking drugs of female and male patients, at risk of awareness, enrolled in a large trial testing the effectiveness of bispectral index (BIS) monitoring. We used multivariate statistical methods to adjust for differences in baseline characteristics, duration and extent of surgery, and anesthetic drug administration in 1079 patients (584 male, 495 female). Female patients had higher BIS values than male patients despite similar amounts of anesthetic drug administration (time-averaged mean [sd] BIS: male 44.6 [7.1] versus female 46.4 [6.6]; P = 0.005). Time to eye opening after anesthesia and time to eligibility to discharge from the postanesthesia care unit were less in women than men (male 13.9 [13.2] min versus female 10.6 [11.6] min; P < 0.001; male 133 [209] min versus female 78 [106] min; P < 0.001, respectively). These differences persisted after multivariate adjustment (both P < or = 0.001). Gender has an independent effect on recovery times in patients undergoing general anesthesia combined with neuromuscular blocking drugs, with women recovering faster than men. Higher BIS values during maintenance of anesthesia in women, despite similar amounts of anesthetic drug administration, suggests that women are less sensitive to the hypnotic effect of anesthetic drugs than men and may help explain faster recovery times in women.

Adult↗
PubMed2005

Validity of unplanned admission to an intensive care unit as a measure of patient safety in surgical patients.

BACKGROUND: An unplanned admission to the intensive care unit within 24 h of a procedure (UIA) is a recommended clinical indicator in surgical patients. Often regarded as a surrogate marker of adverse events, it has potential as a direct measure of patient safety. Its true validity for such use is currently unknown. METHODS: The authors validated UIA as an indicator of safety in surgical patients in a prospective cohort study of 44,130 patients admitted to their hospital. They assessed the association of UIA with intraoperative incidents and near misses, increased hospital length of stay, and 30-day mortality as three constructs of patient safety. RESULTS: The authors identified 201 patients with a UIA; 104 (52.2%) had at least one incident or near miss. After adjusting for confounders, these incidents were significantly associated with UIA in all categories of surgical procedures analyzed; odds ratios were 12.21 (95% confidence interval [CI], 6.33-23.58), 4.06 (95% CI, 2.74-6.03), and 2.13 (95% CI, 1.02-4.42), respectively. The 30-day mortality for patients with UIA was 10.9%, compared with 1.1% in non-UIA patients. After risk adjustment, UIA was associated with excess mortality in several types of surgical procedures (odds ratio, 3.89; 95% CI, 2.14-7.04). The median length of stay was increased if UIA occurred: 16 days (interquartile range, 10-31) versus 2 days (interquartile range, 0.5-9) (P < 0.001). For patients with a UIA, the likelihood of discharge from hospital was significantly decreased in most surgical categories analyzed, with adjusted hazard ratios of 0.41 (95% CI, 0.23-0.77) to 0.58 (95% CI, 0.37-0.93). CONCLUSIONS: These findings provide strong support for the construct validity of UIA as a measure of patient safety.

Adolescent↗
PubMed2005

Fast-track cardiac anesthesia: choice of anesthetic agents and techniques.

Fast-track cardiac anesthesia (FTCA) incorporates early tracheal extubation, decreased length of intensive care unit (ICU) and hospital stay, and (ideally) should avoid or reduce complications to safely achieve cost-savings. A growing body of evidence from randomized trials has identified many anesthetic interventions that can improve outcome after cardiac surgery. These include new short-acting hypnotic, opioid, and neuromuscular blocking drugs. An effective FTCA program requires the appropriate selection of suitable patients, a low-dose opioid anesthetic technique, early tracheal extubation, a short stay in the ICU, and coordinated perioperative care. It is also dependent on the avoidance of postoperative complications such as excessive bleeding, myocardial ischemia, low cardiac output state, arrhythmias, sepsis, and renal failure. These complications will have a much greater adverse effect on hospital length of stay and healthcare costs. A number of clinical trials have identified interventions that can reduce some of these complications. The adoption of effective treatments into clinical practice should improve the effectiveness of FTCA.

Anesthesia↗
PubMed2004

Prehospital hypertonic saline resuscitation of patients with hypotension and severe traumatic brain injury: a randomized controlled trial.

CONTEXT: Prehospital hypertonic saline (HTS) resuscitation of patients with traumatic brain injury (TBI) may increase survival but whether HTS improves neurological outcomes is unknown. OBJECTIVE: To determine whether prehospital resuscitation with intravenous HTS improves long-term neurological outcome in patients with severe TBI compared with resuscitation with conventional fluids. DESIGN, SETTING, AND PATIENTS: Double-blind, randomized controlled trial of 229 patients with TBI who were comatose (Glasgow Coma Scale score, <9) and hypotensive (systolic blood pressure, <100 mm Hg). The patients were enrolled between December 14, 1998, and April 9, 2002, in Melbourne, Australia. INTERVENTIONS: Patients were randomly assigned to receive a rapid intravenous infusion of either 250 mL of 7.5% saline (n = 114) or 250 mL of Ringer's lactate solution (n = 115; controls) in addition to conventional intravenous fluid and resuscitation protocols administered by paramedics. Treatment allocation was concealed. MAIN OUTCOME MEASURE: Neurological function at 6 months, measured by the extended Glasgow Outcome Score (GOSE). RESULTS: Primary outcomes were obtained in 226 (99%) of 229 patients enrolled. Baseline characteristics of the groups were equivalent. At hospital admission, the mean serum sodium level was 149 mEq/L for HTS patients vs 141 mEq/L for controls (P<.001). The proportion of patients surviving to hospital discharge was similar in both groups (n = 63 [55%] for HTS group and n = 57 [50%] for controls; P =.32); at 6 months, survival rates were n = 62 (55%) in the HTS group and n = 53 (47%) in the control group (P =.23). At 6 months, the median (interquartile range) GOSE was 5 (3-6) in the HTS group vs 5 (5-6) in the control group (P =.45). There was no significant difference between the groups in favorable outcomes (moderate disability and good outcome survivors [GOSE of 5-8]) (risk ratio, 0.99; 95% confidence interval, 0.76-1.30; P =.96) or in any other measure of postinjury neurological function. CONCLUSION: In this study, patients with hypotension and severe TBI who received prehospital resuscitation with HTS had almost identical neurological function 6 months after injury as patients who received conventional fluid.

Adult↗
PubMed2004

Where to now with carbon monoxide poisoning?

The controversy regarding the role of hyperbaric oxygen (HBO) in the treatment of carbon monoxide (CO) poisoning has been re-ignited following the publication of a further randomized controlled trial by Weaver et al., the results of which appear to conflict with our findings. Comparative analysis suggests that the apparent outcome differences may be secondary to the design, analysis and interpretation of the results of the two studies. Following careful analysis of these two papers and further results from a study by Raphael et al on 385 CO-poisoned patients, we can still find no convincing evidence favouring HBO therapy. Pending further research to determine optimal oxygen therapy for CO-poisoning, current therapy should involve stratifying patients for risk of a poor outcome. This stratification may be aided by the evolving availability of biochemical markers of brain injury and the finding that patients with transient loss of consciousness and poor performance on neuropsychological tests of the supervisory attention system are at higher risk of neuropsychological sequelae. We propose that those patients most at risk be admitted and receive more prolonged normobaric oxygen therapy whilst those with more minor CO-poisoning should be provided with normobaric oxygen of no less than 6 h duration and certainly until sign and symptom free.

Carbon Monoxide Poisoning↗
PubMed2004

Artifact in the bispectral index in a patient with severe ischemic brain injury.

UNLABELLED: The electroencephalogram (EEG) has been used to predict neurological outcome in patients with anoxic-ischemic brain injury. The bispectral index (BIS) may be a useful alternative. A persistently low BIS associated with burst-suppression of the raw EEG in the setting of minimal hypnotic drug administration may indicate severe cerebral ischemia. We report a case where a patient with presumed ischemic brain injury and an extremely low BIS had an unexplained increase in BIS that could be attributed to electrocardiogram artifact. Care should be taken when interpreting BIS in the setting of anoxic-ischemic brain injury or brain death. IMPLICATIONS: The bispectral index (BIS) can be prone to artifact. In this report we found that electrocardiogram artifact led to an apparent normal BIS in a patient with complete burst-suppression associated with severe brain injury.

Artifacts↗
PubMed2003

Perioperative epidural analgesia and outcome after major abdominal surgery in high-risk patients.

In a primary analysis of a large recently completed randomized trial in 915 high-risk patients undergoing major abdominal surgery, we found no difference in outcome between patients receiving perioperative epidural analgesia and those receiving IV opioids, apart from the incidence of respiratory failure. Therefore, we performed a selected number of predetermined subgroup analyses to identify specific types of patients who may have derived benefit from epidural analgesia. We found no difference in outcome between epidural and control groups in subgroups at increased risk of respiratory or cardiac complications or undergoing aortic surgery, nor in a subgroup with failed epidural block (all P > 0.05). There was a small reduction in the duration of postoperative ventilation (geometric mean [SD]: control group, 0.3 [6.5] h, versus epidural group, 0.2 [4.8] h; P = 0.048). No differences were found in length of stay in intensive care or in the hospital. There was no relationship between frequency of use of epidural analgesia in routine practice outside the trial and benefit from epidural analgesia in the trial. We found no evidence that perioperative epidural analgesia significantly influences major morbidity or mortality after major abdominal surgery.

Abdomen↗
PubMed2003

Reporting of ethical approval and informed consent in clinical research published in leading anesthesia journals.

BACKGROUND: Ethical conduct in human research in anesthesia includes approval by an institutional review board (IRB) or ethics committee and informed consent. Evidence of these is sometimes lacking in journal publications. METHODS: The authors reviewed all publications involving human subjects in six leading anesthesia journals for the year 2001 (n = 1189). Rates of IRB approval and informed consent were examined and compared with potential predictors that included journal, type of publication, and patient demographics (age, sex, elective or emergency status). Rates were compared by use of chi-square and logistic regression. RESULTS: The authors found that IRB approval was documented in 71% of publications and consent was obtained in 66% of publications. Significant variation in IRB approval and consent was found among journals (P < 0.0005) and according to type of publication (P < 0.0005). Because publication type affected rates of IRB approval and consent (trials > mechanistic studies > observational studies > case reports), an analysis restricted to prospective studies also found a significant difference in IRB approval and consent among journals (P < 0.0005). CONCLUSIONS: This study suggests that rates of IRB approval and informed consent vary among publications in anesthesia journals. Clearer guidelines (and author adherence) for all types of publication are needed, both as a protection for research subjects and to maintain public trust in the process.

Anesthesiology↗