A comparison of operative autonomy between men and women in orthopaedic surgical training in Aotearoa New Zealand.

AIM: Recent studies have shown that women training in surgical and procedural specialties achieve less operative autonomy during training than men do. The aim of this study was to discern if there is a disparity in surgical autonomy for orthopaedic trainees by gender. METHODS: This was a retrospective study of operative procedures performed by 53 orthopaedic trainees (43 men, 10 women) in Aotearoa New Zealand over 10 years. The main outcome measure was the amount of surgical autonomy afforded to individual trainees as recorded in the training logbook, categorised as assisting a: primary surgeon with consultant scrubbed or present; or, primary surgeon unsupervised and teaching a colleague the procedure. RESULTS: Data was obtained for 41,622 procedures in total. Eighty point seven percent were performed by men and 19.3% by women. On average men performed 229 cases per year and women performed 251 cases per year. There was an overall significant difference in autonomy between men and women (p <0.001), with men performing more procedures unsupervised than women (45% of all cases versus 39% of all cases). This difference remained significant when trainee year group was accounted for. CONCLUSIONS: We conclude that women orthopaedic trainees in Aotearoa New Zealand perform fewer cases with meaningful autonomy than men. This disparity may have implications for the quality of training received by men versus women.

Cluster analysis of extracellular matrix biomarkers predicts the development of impaired systolic function within 1 year of acute myocardial infarction.

The clinical utility of combining extracellular matrix (ECM) biomarkers to predict the development of impaired systolic function following acute myocardial infarction (AMI) remains largely undetermined. A combination of ELISA and multiplexing assays were performed to measure matrix metalloproteinase (MMP)-2, MMP-3, MMP-8, MMP-9, periostin, N-terminal type I procollagen (PINP) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in plasma samples from 120 AMI patients. All patients had an echocardiogram within 1 year of AMI, and were divided into impaired (n = 37, LVEF < 50%) and preserved (n = 83, LVEF ≥ 50%) systolic function groups. Exploratory factor analysis was performed on log-transformed biomarkers using principle axis analysis with Oblimin rotation. Cluster analysis was performed on log-transformed and normalised biomarkers using Ward's method of minimum variance and the squared Euclidean distance metric. Upon univariate analysis, current smoking, prescription of ACE inhibitors at discharge, peak hsTnT > 610 ng/L (median), MMP-8 levels, Factor 1 scores and Cluster One assignment were predictive of impaired systolic function. Upon multivariate analysis, Cluster One assignment (odds ratio [95% CI], 2.74 [1.04-7.23], p = 0.04) remained an independent predictor of systolic dysfunction in combination with clinical variables. These observations support the usefulness of combining ECM biomarkers using cluster analysis for predicting the development of impaired systolic function in AMI patients.

Reducing length of stay for patients presenting to general surgery with acute non-surgical abdominal pain.

BACKGROUND: Acute abdominal pain is a common surgical presentation. We previously found that over the last decade, more patients were admitted to hospital with non-surgical diagnoses (e.g. gastroenteritis, constipation and non-specific abdominal pain) and length of stay and use of imaging (mainly computed tomography scan) for these patients increased. This study aimed to reduce length of stay and use of imaging for patients admitted with non-surgical abdominal pain. METHODS: A prospective study was undertaken in a tertiary centre evaluating length of stay and use of additional imaging in patients with a non-surgical diagnosis after a quality improvement intervention was implemented. RESULTS: A total of 454 patients were included; 204 (44.9%) presented with non-surgical abdominal pain. During the study period, a significant reduction in computed tomography scan requests was observed (38.5-25.0%, P = 0.037) and an increasing proportion of these patients were discharged within 12 h (33.3-57.1%, P = 0.018). The number of re-presentations remained unchanged (P = 0.358). CONCLUSIONS: The study intervention increased the proportion of patients with non-surgical diagnoses that were successfully discharged within 12 h and reduced the use of additional imaging in this group. This may lead to improved use of health care resources for patients with more urgent diagnoses.

An IL-6-IL-8 score derived from principal component analysis is predictive of adverse outcome in acute myocardial infarction.

INTRODUCTION: Many studies have shown that elevated biomarkers of inflammation following acute myocardial infarction (AMI) are associated with major adverse cardiovascular events (MACE). However, the optimal way of measuring the complex inflammatory response following AMI has not been determined. In this study we explore the use of principal component analysis (PCA) utilising multiple inflammatory cytokines to generate a combined cytokine score that may be predictive of MACE post-AMI. METHODS: Thirteen inflammatory cytokines were measured in plasma of 317 AMI patients, drawn 48-72 h following symptom onset. Patients were followed-up for one year to determine the incidence of MACE. PCA was used to generate a combined score using six cytokines that were detectable in the majority of patients (IL-1ß, -6, -8, and -10; MCP-1; and RANTES), and using a subset of cytokines that were associated with MACE on univariate analysis. Multivariate models using baseline characteristics, elevated individual cytokines and PCA-derived scores determined independent predictors of MACE. RESULTS: IL-6 and IL-8 were significantly associated with MACE on univariate analysis and were combined using PCA into an IL-6-IL-8 score. The combined cytokine score and IL-6-IL-8 PCA-derived score were both significantly associated with MACE on univariate analysis. In multivariate models IL-6-IL-8 scores (OR = 2.77, p = 0.007) and IL-6 levels (OR = 2.18, p = 0.035) were found to be independent predictors of MACE. CONCLUSION: An IL-6-IL-8 score derived from PCA was found to independently predict MACE at one year and was a stronger predictor than any individual cytokine, which suggests this may be an appropriate strategy to quantify inflammation post-AMI. Further investigation is required to determine the optimal set of cytokines to measure in this context.

Long-term hip function in slipped capital femoral epiphysis treated with in situ pinning.

BACKGROUND: In recent years, there has been a trend toward more aggressive management of slipped capital femoral epiphysis (SCFE) with acute anatomical realignment; however, the literature is unclear with regard to the indications for this. QUESTIONS/PURPOSES: To collect long-term patient-reported outcome scores on a group of SCFE patients using modern hip scores. The second aim was to determine whether there is a threshold level of deformity beyond which patients have predictably poor outcomes following in situ pinning. PATIENTS AND METHODS: Patients presenting with SCFE between 2000 and 2009 completed a survey consisting of three modern hip scores and were classified into poor, intermediate, and good outcome groups. The posterior slope angle (PSA) was used to measure slip deformity. We examined the relationship between patient characteristics and functional outcomes. The relationship between PSA score and overall outcome was examined using receiver operator curve (ROC) analysis. RESULTS: The total study population was 63; 14% patients had poor, 29% had intermediate, and 57% had good functional outcomes. The mean Non-Arthritic Hip Scores (NAHSs) for those with poor outcomes was 51, 76 in the intermediate group, and 95 in the good group ( p <0.001). PSA was significantly lower in those with good functional outcomes. ROC analysis demonstrated that a higher PSA was moderately predictive of a poor clinical outcome (area under the curve of 0.668). In both the poor and intermediate outcome groups, 50% of patients had a PSA of 40° or greater, whereas only 31% of those with good clinical outcomes had PSA of 40° or greater. CONCLUSIONS: A significant proportion of post-SCFE patients have ongoing suboptimal hip function after pinning in situ. Those with a PSA more than 40° have a higher chance of a poor outcome.

Can Surgical Registrars Accurately Identify the Urgent from the Non-Urgent Patient Presenting with Acute Abdominal Pain?

BACKGROUND: Acute abdominal pain is a common surgical presentation with a wide range of causes. Differentiating urgent patients from non-urgent patients is important to optimise patient outcomes and the use of hospital resources. The aim of this study was to determine how accurately urgent and non-urgent patients presenting with abdominal pain can be identified. METHODS: A prospective study of consecutive patients admitted with abdominal pain was undertaken. Urgent patients were classified as requiring treatment (theatre, intensive care unit, endoscopy, or radiologic drainage) within 24 h. Differentiation between urgent and non-urgent was made on the basis of the initial assessment prior to the use of advanced imaging. Outcomes were compared to a final classification based on final diagnosis as adjudicated by an expert panel. RESULTS: Of the 301 patients included, 93 (30.9%) were deemed urgent based on initial assessment, compared to 83 (27.6%) on final diagnosis. Overall sensitivity for recognising urgent patients was 74.7% and specificity 89.9%, and overall accuracy was higher for senior registrars compared to junior registrars (p = 0.015). Urgent patients more often looked unwell or had peritonism on examination (39.8 vs. 17.4% and 56.6 vs. 14.7%, respectively, p < 0.001 for both). CONCLUSIONS: Registrars can accurately differentiate urgent from non-urgent patients with acute abdominal pain in the majority of cases. Accuracy was higher amongst senior registrars. The "end-of-the-bed-o-gram" and clinical examination are the most important features used for making this differentiation. This demonstrates that there is no substitute for exposure to acute presentations to improve a trainee's diagnostic skill.

Early radiological and functional outcomes for a cementless press-fit design modular femoral stem revision system.

AIM:: To assess early radiological and functional outcomes of revision hip surgery with a cementless press-fit design femoral stem. PATIENTS AND METHODS:: A retrospective review of 48 consecutive revision total hip replacements using the RECLAIM revision hip system, between October 2012 and August 2015. Radiographic assessment was undertaken with serial anteroposterior (AP) X-rays of the pelvis. Risk factors for subsidence were evaluated. Prospective clinical follow up was performed on 21 patients to assess functional outcomes. RESULTS:: Mean stem subsidence was 1.1 mm (95% confidence interval[CI]: 0.63-1.57). Median follow up of 12 months. An inverse relationship was observed between level of subsidence and femoral stem diameter r = -0.45, p = 0.001. Subsidence at the time of follow-up assessment was correlated with initial subsidence (correlation coefficient rho 0.69, p = 0.001). The mean Merle d'Aubigne score at the latest follow up was 14.2 (range 8-17). The mean OHS was 34.1 (range 15-48). CONCLUSION:: Early radiological and functional outcomes for the RECLAIM revision system showed very low levels of subsidence and good functional outcomes. There was an association with smaller diameter femoral stems and greater levels of subsidence.

Neoadjuvant therapy in rectal cancer: how are we choosing?

BACKGROUND: Neoadjuvant therapy has revolutionized the management of rectal cancer; however, there is a need to examine the factors driving neoadjuvant treatment allocation. This study aimed to describe patterns of treatment allocation for patients with rectal cancer at our institution and identify predictors for receiving neoadjuvant therapy, and for choice of short- or long-course therapy. METHODS: A retrospective review of a prospectively maintained database of 122 patients undergoing surgical resection for rectal cancer with curative intent, between 1 November 2012 and 31 October 2017. Univariate and multivariate analyses were performed to identify factors that determined which patients received neoadjuvant therapy, and whether it was short or long course. RESULTS: Eighty-six patients (70%) received neoadjuvant therapy. Independent predictors for receiving neoadjuvant therapy were T3-4 tumours (P < 0.001), node-positive disease (P = 0.005) and mid (P = 0.045) or low rectal cancers (P < 0.001). Of those receiving neoadjuvant therapy, 38 (44%) received short course and 48 (56%) received long course. Node-positive disease was the only predictor for receiving long rather than short-course neoadjuvant therapy (P = 0.002). Overall, these factors predicted 76% of neoadjuvant treatment allocation. Our predictor model identified important areas of variance in our decision-making. CONCLUSION: Utilizing the identified factors, it appears that consistent decisions regarding neoadjuvant therapy are being made the majority of the time. These decisions are largely driven by T and N stage as well as tumour height. Mesorectal fascia involvement, pre-treatment carcinoembryonic antigen, age and comorbidity also influenced decision-making to a lesser and more variable extent.

Benzoyl peroxide + chlorhexidine versus chlorhexidine alone skin preparation to reduce Propionibacterium acnes: a randomized controlled trial.

BACKGROUND: Traditional skin preparation for shoulder surgery is not specific for Propionibacterium acnes. Topical benzoyl peroxide for 48 h preoperatively has been shown to reduce the bacterial load of P. acnes on the skin. Our aim was to investigate whether skin preparation with a single application of benzoyl peroxide combined with 2% chlorhexidine/alcohol immediately prior to surgery was superior to 2% chlorhexidine/alcohol alone at inhibiting P. acnes. METHODS: We conducted a single-blinded interventional study. Each shoulder of the participant was assigned a different preparation through a randomization process. Two sites were assessed per shoulder. The intervention was the application of benzoyl peroxide followed by chlorhexidine/alcohol to the shoulder. The control was two applications of 2% chlorhexidine/alcohol. Superficial skin swabs for semi-quantitative culture were taken pre- and post-skin preparation. RESULTS: A total of 22 male participants were randomized. All participants were colonized with P. acnes on baseline swabs. We found complete inhibition of P. acnes at 14 days at 80% of sites prepared with benzoyl peroxide + chlorhexidine/alcohol compared with 86% inhibition at shoulder sites prepared with chlorhexidine alone. CONCLUSION: There was no reduction in the growth of P. acnes over 14 days with chlorhexidine/alcohol and benzoyl peroxide compared with chlorhexidine alone. On the basis of these results, the addition of benzoyl peroxide at the time of surgery does not appear to increase the efficacy of the surgical preparation for inhibiting P. acnes growth.

Platelets regulate leucocyte responses to Toll-like receptor stimulation.

OBJECTIVES: Platelets are important regulators of vascular thrombosis and inflammation and are known to express Toll-like receptors (TLRs). Through TLRs, platelets mediate a number of responses by interacting with leucocytes. Here, we report the extent to which platelets modulate in vitro peripheral blood mononuclear cells (PBMCs) and granulocyte responses to TLR4, TLR2/1 and TLR2/6 stimulation in healthy subjects. METHODS: Peripheral blood mononuclear cells and granulocytes from 10 healthy volunteers were cultured alone or cocultured with platelets. Cultures were left unstimulated or stimulated with 1 or 100 ng mL-1 of either LPS (TLR4 agonist), Pam3CSK4 (TLR2/1 agonist) or fibroblast-stimulating lipopeptide (FSL)-1 (TLR2/6 agonist). Neutrophil activation (CD66b expression), monocyte activation (HLA-DR), granulocyte elastase production and PBMC cytokine and chemokine production were examined. RESULTS: Platelet coculture decreased neutrophil CD66b expression in response to LPS, Pam3CSK4 and FSL-1, and modestly decreased monocyte HLA-DR expression in response to low-dose LPS. Platelets reduced granulocyte elastase secretion in response to low doses of all TLR agonists tested. In response to LPS, platelet coculture reduced IL-6, tumor necrosis factor (TNF)-α and MIP-1ß production, and increased IL-10 production by PBMCs. In response to FSL-1, platelets increased IL-6, IL-10 and MIP-1ß production, but reduced TNF-α production. Platelet coculture did not alter PBMC cytokine/chemokine production in response to Pam3CSK4. CONCLUSION: This study challenges the notion that platelets act solely in a pro-inflammatory manner. Rather, platelets are complex immunomodulators that regulate leucocyte responses to TLR stimulation in a TLR agonist-specific manner. Platelets may modulate leucocyte responses to dampen inflammation, and this platelet effect may play an important role in reducing inflammation-mediated host damage.

Patients requiring an acute operation: where are the delays in the process?

BACKGROUND: Delays to surgery for patients requiring an acute operation are associated with increased morbidity and mortality. A recent study from our institution observed long waiting times for patients booked for an acute operation. The aim of this study was to evaluate the patient's progress from presentation to arrival in the operating theatre and to identify where delays occurred. METHODS: Patients undergoing acute general surgery between July 2016 and May 2017 were studied. Data were obtained for time of presentation, imaging, theatre and booking. A time interval from presentation to booking for theatre of greater than 6 h was defined as a diagnostic delay. A time interval from booking to theatre greater than the category defined time (four-level priority system) was defined as a logistic delay. RESULTS: A total of 683 patients were included. A diagnostic delay was observed in 55.1%. This occurred more frequently in patients who required imaging prior to their operation (82.5 versus 41.1%, P < 0.001). Logistic delay occurred in 31.0% of the patients, and this was most common for patients booked as a category 3 (requiring surgery within 6 h, 41.8%, P < 0.001). Patients who had a diagnostic delay were significantly more likely to have a post-operative complication compared to patients who did not (17.2 versus 10.0%, P = 0.009). CONCLUSION: There are significant delays associated with patients presenting to the acute general surgery service and their transition to theatre. Addressing both the diagnostic and the logistic delays in our institution should result in a significant improvement in patient care.

Systematic review of diagnostic pathways for patients presenting with acute abdominal pain.

PURPOSE: Abdominal pain is the most common reason for surgical referral. Imaging, aids early diagnosis and treatment. However unnecessary requests are associated with increased costs, radiation exposure and increased length of stay. Pathways can improve the quality of the diagnostic process. The aim of this systematic review was to identify the current evidence for diagnostic pathways and their use of imaging and effect on final outcomes. DATA SOURCES: A systematic search of Embase, Medline and Cochrane databases was performed using keywords and MeSH terms for abdominal pain. STUDY SELECTION: All papers describing a pathway and published between January 2000 and January 2017 were included. DATA EXTRACTION: Data was obtained about the use of imaging, complications and length of stay. Quality assessment was performed using MINORS and Level of Evidence. RESULTS: Ten articles were included, each describing a different pathway. Five studies based the pathway on literature reviews alone and five studies on the results of their prospective study. Of the latter five studies, four showed that routine imaging increased diagnostic accuracy, but without showing a reduction in length of stay, complication rate or mortality. None of the studies included evaluated use of hospital resources or costs. CONCLUSION: Pathways incorporating routine imaging will improve early diagnosis, but has not been proven to reduce complication rates or hospital length of stay. On the basis of this systematic review conclusions can therefore not be drawn about the pathways described and their benefit to the diagnostic process for patients presenting with abdominal pain.

Review of appendicectomies over a decade in a tertiary hospital in New Zealand.

BACKGROUND: Acute appendicectomy is the most common emergency operation for patients with abdominal pain. In the last decade, computed tomography (CT) scans have increasingly been used to aid in the diagnosis in order to reduce the negative appendicectomy rate. The aim of this study was to evaluate our institution's negative appendicectomy rate and the use of pre-operative imaging. METHODS: A retrospective review was undertaken for all adult patients (>16 years), who underwent an appendicectomy on emergency basis in the years 2004, 2009 and 2014. Cases were identified from the hospital electronic theatre record system. Data were also obtained from the patients records and laboratory reports. RESULTS: A total of 874 patients were included, 227 in 2004, 308 in 2009 and 339 in 2014. The negative appendicectomy rate was 29.1% in 2004, 20.1% in 2009 and 19.5% in 2014 (P = 0.014). Negative appendicectomies were more common in women (P = <0.001), patients between the ages of 16-30 years (P = <0.001) and were associated with low inflammatory markers (median white cell count of 10.2, C-reactive protein of 8, P = <0.001). The use of CT scan prior to operation increased between 2009 and 2014 (34 (11.0%) versus 64 (18.9%), P = <0.001). CONCLUSION: Though the number of appendicectomies being performed in our institution has increased over the last decade, the negative appendicectomy rate remains fairly static and the increased use of CT scans did not further decrease the proportion of negative appendicectomies between 2009 and 2014.

Contemporary antiplatelet therapy in acute coronary syndromes: are there differences in outcomes and discontinuation between clopidogrel and ticagrelor?

BACKGROUND/AIM: We studied clinical outcomes and discontinuation rates in a 'real-world' population presenting with myocardial infarction treated with ticagrelor or clopidogrel. METHODS: Between January 2012 and May 2015, 992 patients with acute myocardial infarction undergoing invasive management and adequately pre-treated with dual antiplatelet therapy were prospectively enrolled. Platelet aggregation was measured using the Multiplate analyser. Baseline characteristics, in-hospital outcomes and 1-year outcomes were collected. RESULTS: Patients treated with ticagrelor were younger and less likely to be diabetic, have a previous myocardial infarction or present with a ST-elevation myocardial infarction (all P < 0.05). Those treated with ticagrelor also had lower CRUSADE (Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the ACC/AHA guidelines; 20 ± 9.4 vs 23 ± 10.1, P < 0.0001) and GRACE (119 ± 28 vs 126 ± 32, P = 0.002) scores. High platelet reactivity was greatly reduced with ticagrelor compared to clopidogrel (16.1% vs 37.0%, respectively; P < 0.0001). Non-coronary artery bypass grafting-related thrombolysis in myocardial infarction major and minor bleeding occurred at similar rates in those treated with ticagrelor and clopidogrel. Rates of drug discontinuation in those treated with ticagrelor and clopidogrel were similar in hospital (20.2% vs 16.2%, P = 0.18) and between discharge and 1 year (29.9% vs 27.9%, P = 0.63). However, discontinuation due to dyspnoea, (3.3% vs 0%, P < 0.0001) and discontinuation due to any possible drug-related adverse event (9.3% vs 2.2%, P = 0.0001) was more common in those treated with ticagrelor compared to clopidogrel CONCLUSION: Ticagrelor is paradoxically being used in lower-risk patients rather than those most likely to benefit. Ticagrelor was associated with similar rates of bleeding but higher discontinuation rates due to adverse effects compared to clopidogrel.

Differing Clinical Characteristics Between Young and Older Patients Presenting with Myocardial Infarction.

BACKGROUND: To date, there has been no detailed study of the risk factors and clinical characteristics of patients presenting with myocardial infarction (MI) at a young age in our region. The purpose of this study was to assess the rate and clinical profile of those presenting with young MI in New Zealand. METHODS: We identified a cohort of 1199 patients presenting with acute MI between January 2012 and November 2015 from the Wellington Acute Coronary Syndrome Registry. We compared those presenting with young MI, defined as presentation with MI aged 50 years or younger, to those aged over 50 years. RESULTS: Myocardial infarction at a young age occurred in 154 (12.8%) patients. Compared to those in the older MI group, the young MI group were more likely to be male (80% vs. 71%, p=0.026), of Maori or Pacific Island ethnicity (21% vs. 10%, p<0.0001), have a higher BMI (31kg/m2 vs. 29kg/m2, p<0.0001), have a family history of premature coronary artery disease (49% vs. 34%, p<0.0001) and to be current smokers (47% vs. 20%, p<0.001). Young MI patients were less likely to have hypertension, dyslipidaemia and diabetes than the older MI patient population. Within the young MI group 36% had none or only one traditional risk factor for MI, and would have been classified as low risk prior to their index event. CONCLUSION: Those with young MI accounted for 12.8% of our cohort and had a different risk factor profile to the older MI group with smoking and obesity being particularly prevalent.

Pharmacological therapy following acute coronary syndromes in patients with atrial fibrillation: how do we balance ischaemic risk with bleeding risk?

BACKGROUND: Dual anti-platelet therapy (DAPT) with aspirin and a P2Y12receptor antagonist is standard of care following an acute coronary syndrome (ACS), as it has been shown to reduce recurrent myocardial infarction (MI) and death. In atrial fibrillation (AF) patients, the use of oral anticoagulants (OACs) is the standard of care as these agents have been shown to reduce the risk of stroke and death. Current guidelines suggest that decisions around antithrombotic therapy should be made by assessing ischaemic and bleeding risks. The aim of this study was to examine current pharmacotherapy of AF inpatients with ACS. METHODS: We prospectively enrolled ACS patients being managed invasively with a medical history of AF, or those in AF during admission ECG, from the pre-existing Wellington ACS registry. Enrolment criteria included pre-treatment on DAPT. Demographics, clinical characteristics, management, in-hospital outcomes and discharge medications were recorded. RESULTS: At discharge, only 11.8% of AF patients were prescribed an OAC and this was not related to risk of stroke (CHA2DS2-VASc score), bleeding (CRUSADE score) or any other clinical characteristics. However, discharge OAC use was associated with whether the patient was treated with an OAC at admission (OR 14, CI 3.4-58, p=0.001). DAPT was the default discharge treatment and occurred in 72% of AF patients. A moderate correlation between stroke risk and bleeding risk was identified (rs=0.68, p=0.01). A group of 44 (47%) patients were identified who were at high risk of stroke (CHA2DS2-VASc ≥2) and low risk of bleeding (CRUSADE score ≤30). CONCLUSION: At discharge we observed a very low rate of OAC prescription. Despite most AF patients being high risk for stroke, DAPT was the preferred treatment option. Our data suggests there is a group of patients with high stroke risk and relatively low bleeding risk, in who OAC use may be appropriate. Developing a guideline to assist clinicians in targeting this group of patients may help improve outcomes in AF patients following MI.

Methodological considerations for the assessment of ADP induced platelet aggregation using the Multiplate® analyser.

Factors affecting the Multiplate® assay's analytical precision have not been well defined. We investigated the effect of methodological factors on the measurement of ADP-induced platelet aggregation using the Multiplate® assay. ADP-induced platelet aggregation was analysed in whole blood using the Multiplate® assay. We tested the reproducibility of measurement, the effect of different anticoagulants (hirudin, citrate and heparin) and the effect of time delay (15, 30, 45, 60, 120 and 180 minutes) between sampling and analysis in patients. The use of a manual calibrated pipette with the Multiplate® analyser was also tested. The mean coefficient of variation (CV) using the manufacturers recommended methods was 10.8 ± 8.7% (n = 30). When compared to hirudin (359.5 ± 309 AU*min) the use of heparin (521.0 ± 316 AU*min, p = 0.0015) increased platelet aggregation, while the use of sodium citrate (245.0 ± 209 AU*min, p = 0.003) decreased the platelet aggregation (n = 20). The addition of CaCl2 to the citrate-anticoagulated blood resulted in platelet aggregation levels similar to hirudin. Platelet aggregation varied with time delay (n = 20). When compared to platelet aggregation at 30 minutes (391.1 ± 283 AU*min), platelet aggregation was reduced at 60 minutes (335.2 ± 251.6 AU*min, p < 0.05), 120 minutes (198.8 ± 122.9 AU*min, p < 0.001) and 180 minutes (160.7 ± 92 AU*min, p < 0.001). The use of a manual calibrated pipette did not significantly reduce the mean CV in the assay (n = 20). Methodological factors such as the anticoagulant used and the time delay should be standardised where possible to reduce variability, and allow thresholds derived from one study to be comparable across multiple studies.

A study of airline pilot morbidity.

INTRODUCTION: It has long been believed that airline pilots are healthier than the general population. There are a number of reasons why this should be the case. However, there is very little evidence to support this belief as fact. This study investigates the health of the pilot population of an Oceanic based airline compared to the health of the general population. METHODS: Pilots who conducted their medical certificate renewal at the airline's medical unit between 1 November 2009 and 31 October 2010 were included. A medical questionnaire was completed by each pilot at the time of their medical certificate renewal. Data from the questionnaire was entered into a database as well as the pilot's BMI, blood pressure, lipid profile, and blood glucose level. The comparison population was the population who completed the New Zealand Health Survey (NZHS) between 2006-2007. Demographic, lifestyle characteristics, and health status data from the pilots was compared to the NZHS using a Chi-squared test. RESULTS: Included in the study were 595 pilots. With respect to most medical conditions, pilots had a lower prevalence when compared to the general population. Pilots had a higher prevalence of kidney disease (3.3% vs 0.6%) and melanoma skin cancer (19 per 1000 vs 0.4 per 1000). DISCUSSION: This study suggests that pilots in New Zealand are healthier than the general population with respect to most medical conditions. The two medical conditions that were identified as being overrepresented in pilots may be the result of the occupational environment.

Interactions between heart rate variability and pulmonary gas exchange efficiency in humans.

The respiratory component of heart rate variability (respiratory sinus arrhythmia, RSA) has been associated with improved pulmonary gas exchange efficiency in humans via the apparent clustering and scattering of heart beats in time with the inspiratory and expiratory phases of alveolar ventilation, respectively. However, since human RSA causes only marginal redistribution of heart beats to inspiration, we tested the hypothesis that any association between RSA amplitude and pulmonary gas exchange efficiency may be indirect. In 11 patients with fixed-rate cardiac pacemakers and 10 healthy control subjects, we recorded R-R intervals, respiratory flow, end-tidal gas tension and the ventilatory equivalents for carbon dioxide and oxygen during 'fast' (0.25 Hz) and 'slow' paced breathing (0.10 Hz). Mean heart rate, mean arterial blood pressure, mean arterial pressure fluctuations, tidal volume, end-tidal CO(2), and were similar between pacemaker and control groups in both the fast and slow breathing conditions. Although pacemaker patients had no RSA and slow breathing was associated with a 2.5-fold RSA amplitude increase in control subjects (39 +/- 21 versus 97 +/- 45 ms, P < 0.001), comparable (main effect for breathing frequency, F(1,19) = 76.54, P < 0.001) and reductions (main effect for breathing frequency, F(1,19) = 23.90, P < 0.001) were observed for both cohorts during slow breathing. In addition, the degree of (r = 0.36, P = 0.32) and reductions (r = 0.29, P = 0.43) from fast to slow breathing were not correlated to the degree of associated RSA amplitude enhancements in control subjects. These findings suggest that the association between RSA amplitude and pulmonary gas exchange efficiency during variable-frequency paced breathing observed in prior human work is not contingent on RSA being present. Therefore, whether RSA serves an intrinsic physiological function in optimizing pulmonary gas exchange efficiency in humans requires further experimental validation.

Effective nonanatomical endoscopy training produces clinical airway endoscopy proficiency.

We studied the effectiveness of two nonanatomical endoscopic dexterity training models: "Choose the Hole" and Dexter. Effectiveness was assessed in terms of time spent training, subjective rating, performance on an anatomical manikin, and clinical performance on fellow participants who acted as awake subjects. Forty-three anesthesia specialists, trainees, and technicians volunteered. Performances were videotaped, timed, and scored with a Global Rating Scale (GRS) from 1 (very poor) to 5 (clearly superior). The Dexter group spent more time training than the Choose the Hole group (median time [range], 152 min [70-510 min] versus 75 min [17-281 min]; P < 0.01). Subjective ratings were better in the Dexter group. In clinical bronchoscopy, the Dexter group was faster (30.7 s [17.1-43.5 s] versus 36.6 s [22.8-105.1 s]; P = 0.02) and had higher GRS scores (mean [sd]: 3.0 [0.4] versus 2.6 [0.6]; P = 0.04), indicating superior performance. Clinical and manikin performance (GRS scores) were significantly correlated (rho = 0.62; P = 0.0001). Benchmark levels of clinical bronchoscopic performance can be anticipated from bench model performance without a clinical learning curve. Dexter is a more effective model for learning endoscopic dexterity than the Choose the Hole model. Airway topicalization with lidocaine in a dose range consistent with published series (490-980 mg or 7.14-14.77 mg/kg) resulted in a frequent incidence of side effects. No major adverse events occurred.