Systematic review and meta-analysis of method comparison studies of Masimo pulse co-oximeters (Radical-7™ or Pronto-7™) and HemoCue® absorption spectrometers (B-Hemoglobin or 201+) with laboratory haemoglobin estimation.

We assessed agreement in haemoglobin measurement between Masimo pulse co-oximeters (Rad-7™ and Pronto-7™) and HemoCue® photometers (201+ or B-Hemoglobin) with laboratory-based determination and identified 39 relevant studies (2915 patients in Masimo group and 3084 patients in HemoCue group). In the Masimo group, the overall mean difference was -0.03 g/dl (95% prediction interval -0.30 to 0.23) and 95% limits of agreement -3.0 to 2.9 g/dl compared to 0.08 g/dl (95% prediction interval -0.04 to 0.20) and 95% limits of agreement -1.3 to 1.4 g/dl in the HemoCue group. Only B-Hemoglobin exhibited bias (0.53, 95% prediction interval 0.27 to 0.78). The overall standard deviation of difference was larger (1.42 g/dl versus 0.64 g/dl) for Masimo pulse co-oximeters compared to HemoCue photometers. Masimo devices and HemoCue 201+ both provide an unbiased, pooled estimate of laboratory haemoglobin. However, Masimo devices have lower precision and wider 95% limits of agreement than HemoCue devices. Clinicians should carefully consider these limits of agreement before basing transfusion or other clinical decisions on these point-of-care measurements alone.

Stability of absolute copy number of housekeeping genes in preeclamptic and normal placentas, as measured by digital PCR.

Measuring mRNA expression is fundamental to placental research. Ideally, mRNA transcript numbers are directly quantified. However, PCR analysis using the ΔΔCT method relies on the stability of housekeeping genes and only reports relative expression. Digital PCR (dPCR) directly quantifies mRNA copy number and is more accurate than quantitative PCR. We quantified absolute mRNA copy number of housekeeping genes in normotensive pre-term (n = 20), severe preeclamptic (n = 11) and term (n = 12) placenta using dPCR. Whilst there was some variation, we confirm absolute mRNA copy number of GAPDH, TOP1, CYC1 and YWHAZ in placenta does not significantly alter between these cohorts, or across gestation.

Comparison of Massimo Pronto-7 and HemoCue Hb 201+ with laboratory haemoglobin estimation: a clinical study.

We prospectively studied agreement in haemoglobin estimation between two point-of-care devices (Pronto-7(®) Pulse CO-Oximetry(™), Masimo Corporation, Irvine, California, USA and HemoCue(®) Hb 201 +, HemoCue, Angelholm, Sweden) and an automated laboratory analyser (Sysmex XE5000, Sysmex Corporation, Kobe, Japan). Venous blood sampling and finger co-oximeter readings were performed on 141 pregnant women undergoing routine mid-trimester haemoglobin assessment. Three replicate measures were performed and analysis used Bayesian-based variance component modelling to provide estimates of repeatability, between person within method bias and precision. Repeatability, assessed by coefficient of variation, was higher for Pronto-7(®) (2.3%) compared to HemoCue(®) (5.2%). Fixed bias (mean difference, device - laboratory) was +1.18 (standard deviation 1.19) g/dl and - 0.01 (standard deviation 1.34) g/dl for Pronto-7(®) and HemoCue(®) respectively, with no statistical evidence of proportional bias. Based upon a single device reading, the 95% prediction limits for Pronto-7(®) were -1.2 to 3.6 g.dl-1 and HemoCue(®) were -2.7 to 2.7 g/dl. For both devices precision was not meaningfully improved by averaging replicate readings. However, repeated readings may allow detection of aberrant results. Overall both devices are imprecise and 95% prediction limits wide. We present further prediction limits, derived from the posterior distribution and adjusted for any fixed bias for set levels of probability (certainty). These may be used to support clinical decisions when using these point-of-care devices.

Time to get comfortable with a labour epidural.

Women frequently request regional analgesia during labour, yet little is known about how long it takes before they become comfortable. This prospective observational study aimed to determine various time-points following maternal request for regional analgesia in labour until comfort was achieved. It was conducted in two tertiary referral centres for maternity care in Australia between December 2009 and May 2010.Midwives and anaesthetists recorded times of maternal request for regional analgesia, anaesthetist contact,anaesthetist's arrival in the labour room, local anaesthetic infiltration on starting the procedure, injection of neuraxial local anaesthetic and first report of maternal comfort. Composite median times and interquartile range were recorded for maternal request to anaesthetist arrival, anaesthetist arrival to maternal comfort and total time from request to comfort. Statistical modelling and regression analyses assessed possible factors associated with these time intervals. A P value <0.05 was considered significant. Of the 324 maternal requests, 244 out of 324 (75.3%, 95% confidence interval 70.2% to 79.9%) were recorded as having achieved satisfactory labour analgesia. Median interquartile range times observed were: maternal request to anaesthetist arrival: 20 (10 to 35) minutes; anaesthetist arrival to maternal comfort: 40 (30 to 50) minutes; and total time from request to comfort: 65 (50 to 85) minutes. We have shown that approximately one hour is required for a mother to achieve comfort following her request for epidural analgesia during labour. Our findings are likely to provide useful information for antenatal education, enhance informed consent and improve the provision of anaesthetic services for labour analgesia.

Peak plasma anti-Xa levels after first and third doses of enoxaparin in women receiving weight-based thromboprophylaxis following caesarean section: a prospective cohort study.

BACKGROUND: Women undergoing caesarean section are at higher risk for thromboembolic complications following delivery than other parturients. The aim of this study was to determine whether higher doses of enoxaparin based on body weight are safe and more likely to achieve plasma anti-Xa levels within the accepted thromboprophylactic range. METHODS: We undertook a prospective cohort study of 80 women undergoing caesarean section in a tertiary obstetric hospital with >6000 deliveries per year. Enoxaparin was administered after caesarean section using the Royal College of Obstetricians and Gynaecologists weight-adjusted dosing guidelines. Plasma anti-Xa levels were measured at baseline and 3-4 h after enoxaparin administration on days one and three postoperatively. The main outcomes of interest were plasma anti-Xa levels and the proportion of patients with plasma anti-Xa levels in the range of 0.2-0.4 IU/mL. RESULTS: The proportion of women with anti-Xa levels between 0.2 and 0.4 IU/mL was 72% (95% CI 60-81%). Unadjusted mean anti-Xa levels were 0.26 ± 0.09 IU/mL and 0.28 ± 0.08 IU/mL on day one and day three respectively. No woman had levels >0.48 IU/mL. CONCLUSION: The majority of women receiving weight-based enoxaparin thromboprophylaxis following caesarean section achieved plasma anti-Xa levels within the putative thromboprophylactic range. No woman achieved levels associated with an increased risk of bleeding (>0.8 IU/mL). These findings provide a safety basis for a large prospective study using this regimen.

Brachial plexopathy in laparoscopic-assisted rectal surgery: a case series.

BACKGROUND: Brachial plexopathy may be caused by malpositioning during surgery when the body's protective mechanism is lost under general anaesthesia. It is the second commonest nerve injury reported in the anaesthetized patient. The exact incidence in colorectal surgery is unclear but there have been numerous cases reported of brachial plexopathy as an adverse event following colorectal surgery. Although it is widely believed that these injuries are preventable by paying special attention to vulnerable areas during patient positioning and by careful intraoperative monitoring, it appears that nerve injury may still occur. METHODS: Patients with post-operative brachial plexopathy in our prospectively kept database were identified. The patient notes were reviewed and documented. RESULTS: In our series, five cases of brachial plexopathy were still observed despite careful precautions taken to prevent nerve injury. The proposed mechanism of nerve injury in our series is most likely due to nerve stretch. All symptoms resolved with the longest taking 7 months before resolution. During this period from 2005 to 2010 our unit performed 548 laparoscopic colorectal resections. The relative incidence of brachial plexopathy in our series is approximately 1 %. CONCLUSION: We recommend certain precautionary steps to follow, as well as predisposing and perioperative factors to be aware of when anticipating a laparoscopic colorectal procedure. These may all contribute to minimising brachial plexopathy which most likely is under-reported in laparoscopic colorectal surgery but is a preventable morbidity to the patient.

Preoperative diagnosis of Lynch syndrome with DNA mismatch repair immunohistochemistry on a diagnostic biopsy.

BACKGROUND: DNA mismatch repair immunohistochemistry on tumor tissue is a simple, readily available, and cost-effective method of identifying patients with Lynch syndrome in the postoperative setting. The aim of the study was to assess whether the mismatch repair status of a colorectal cancer can be confirmed by mismatch repair immunohistochemistry on preoperative biopsy. DESIGN: Germline positive patients with Lynch syndrome were identified from a prospectively collected Familial Cancer Clinic database. Preoperative colorectal cancer biopsy specimens were obtained from the source pathology provider to generate a cohort of matched preoperative and postoperative specimens. The specimens were sectioned and stained for 4 mismatch repair proteins (MLH1, MSH2, MSH6, PMS2). An age-matched cohort to compare specimens was selected from Bethesda positive but mismatch repair immunohistochemistry negative patients. All slides were reviewed by a single blinded pathologist. The Wilson method was used to calculate a true underlying proportion of patients for whom the preoperative result matched the postoperative test result with a 95% confidence interval. RESULTS: Of 128 germline positive mutation carriers, 40 patients (mean age 41, SD 11.3) had colorectal resections. Thirty-three preoperative specimens were retrievable and were matched with biopsies from 33 controls. The germline mutations included in the study were 8 MLH1, 19 MSH2, 3 MSH6, and 2 PMS2. In patients where germline positive status was known, sensitivity was 100% (95% CI 89.2-100) and specificity was 100% (95% CI 89.2-100). Identical sensitivity and specificity were observed in 33 age-matched patients. The sensitivity of the endoscopic biopsy in predicting germline status was 94.9% (95% CI 80.4-98.3). CONCLUSION: The mismatch repair disease status of a colorectal cancer can be reliably confirmed by mismatch repair immunohistochemistry on a diagnostic colorectal cancer biopsy sample before definitive surgery. Ascertaining a diagnosis of Lynch syndrome before definitive surgery can influence surgical planning.

Physiology of diffuse esophageal spasm (DES)--when normal swallows are not normal.

BACKGROUND: Diffuse esophageal spasm (DES) is characterized on manometry by a combination of simultaneous contractions and normal swallows. The aim of this study was to examine the manometric characteristics of simultaneous and 'normal' swallows in patients with DES patients compared with normal controls. METHODS: Manometric studies from 69 patients with DES and 20 controls were analysed to determine the proportion of normal, hypertensive, ineffective and simultaneous contractions, and the velocity of propagation along the esophagus, the duration and amplitude of contraction and the relaxation characteristics (nadir and duration) of the lower esophageal sphincter. KEY RESULTS: The propagation velocity was the only significant difference between normal swallows and simultaneous contractions in DES patients (middle third: 49.2 VS 101.2 mm s(-1), P ≤ 0.001 lower third: 44.1 VS 88.7 mm s(-1), P ≤ 0.001). 'Normal' swallows in patients with DES had a greater velocity of propagation than those in age-matched control subjects (middle third: 49.2 VS 37.0 mm s(-1), P = 0.02, lower third: 44.1 VS 23.3 mm s(-1), P ≤ 0.001). CONCLUSIONS & INFERENCES: As expected, simultaneous contractions of DES patients differ from 'normal' swallows in DES patients mainly regarding the velocity of propagation of contraction but are similar in amplitude, however 'normal' swallows of DES patients are also more rapidly propagated along the esophagus than normal swallows of a control group suggesting that all swallows in DES are affected to some degree by the same process.

Do smoking cessation programmes influence geographical inequalities in health? An evaluation of the impact of the PEGS programme in Christchurch, New Zealand.

OBJECTIVE: To identify the impact of a smoking cessation programme on area-based social and ethnic inequalities in smoking rates through social and ethnic differences in enrolment and quitting. METHODS: Analysis of records of 11 325 patients who enrolled in an innovative smoking cessation programme in Christchurch, New Zealand between 2001 and 2006. We compare enrolment, follow-up, quitting and impact on population smoking rates in the most and least deprived neighbourhoods and the neighbourhoods with the lowest and highest proportions of Maori. RESULTS: Enrolment as a proportion of the population was higher from the most deprived areas but as a proportion of neighbourhood smokers, it was lower. Enrolees from the least deprived quintile were 40% more likely to quit than those from the most deprived quintile. Smoking rates were 2.84 (2.75 to 2.93) times higher in the most deprived neighbourhoods. If the programme had not been available we estimate that this differential would have reduced to 2.81 (2.72 to 2.90). In neighbourhoods with the highest proportion of Maori, smoking rates were 2.33 (2.26 to 2.41) times higher and we estimate that without the programme smoking rates would be 2.30 (2.23 to 2.37) times higher. CONCLUSIONS: Although enrolees were drawn from a wide variety of backgrounds, those most likely to quit tended to reside in affluent areas or areas with a low proportion of Maori. There was no evidence that this smoking cessation programme increased or decreased inequalities within the Christchurch population. For smoking cessation programmes to have an impact on health inequalities more effort is required in targeting hard-to-reach groups and in encouraging them to quit.

The neighbourhood effects of geographical access to tobacco retailers on individual smoking behaviour.

OBJECTIVE: To investigate whether neighbourhood measures of geographical accessibility to outlets selling tobacco (supermarkets, convenience stores and petrol stations) are associated with individual smoking behaviour in New Zealand. METHODS: Using geographical information systems, travel times from the population-weighted centroid of each neighbourhood to the closest outlet selling tobacco were calculated for all 38,350 neighbourhoods across New Zealand. These measures were appended to the 2002/03 New Zealand Health Survey, a national survey of 12, 529 adults. Two-level logistic regression models were fitted to examine the effects of neighbourhood locational access upon individual smoking behaviour after controlling for potential individual- and neighbourhood-level confounding factors, including deprivation and urban/rural status. RESULTS: After controlling for individual-level demographic and socioeconomic variables, individuals living in the quartiles of neighbourhoods with the best access to supermarkets (OR 1.23, 95% CI 1.06 to 1.42) and convenience stores (OR 1.19, 95% CI 1.03 to 1.38) had a higher odds of smoking compared with individuals in the worst access quartiles. However, the association between neighbourhood accessibility to supermarkets and convenience stores was not apparent once other neighbourhood-level variables (deprivation and rurality) were included. CONCLUSIONS: At the national level, there is little evidence to suggest that, after adjustment for neighbourhood deprivation, better locational access to tobacco retail provision in New Zealand is associated with individual-level smoking behaviour.

A national study of neighbourhood access to gambling opportunities and individual gambling behaviour.

OBJECTIVE: To investigate associations between neighbourhood accessibility to gambling outlets (non-casino gaming machine locations, sports betting venues and casinos) and individual gambling behaviour in New Zealand. DESIGN: A Geographical Information Systems (GIS) measure of neighbourhood access to gambling venues. Two-level logistic regression models were fitted to examine the effects of neighbourhood access on individual gambling behaviour after controlling for potential individual- and neighbourhood-level confounding factors. SETTING: 38,350 neighbourhoods across New Zealand. PARTICIPANTS: 12,529 respondents of the 2002/03 New Zealand Health Survey. RESULTS: Compared with those living in the quartile of neighbourhoods with the furthest access to a gambling venue, residents living in the quartile of neighbourhoods with the closest access were more likely (adjusted for age, sex, socio-economic status at the individual-level and deprivation, urban/rural status at the neighbourhood-level) to be a gambler (OR 1.60, 95% CI 1.20 to 2.15) or problem gambler (OR 2.70, 95% CI 1.03 to 7.05). When examined independently, neighbourhood access to venues with non-casino gaming machines (gambling: OR 1.67, 95% CI 1.28 to 2.18; problem gambling: OR 2.71, 95% CI 1.45 to 5.07) and sports betting venues (gambling: OR 1.67, 95% CI 1.28 to 2.18; problem gambling: OR 2.71, 95% CI 1.45 to 5.07) were similarly related. CONCLUSIONS: Neighbourhood access to opportunities for gambling is related to gambling and problem gambling behaviour, and contributes substantially to neighbourhood inequalities in gambling over and above-individual level characteristics.

The contextual effects of neighbourhood access to supermarkets and convenience stores on individual fruit and vegetable consumption.

BACKGROUND: It is often suggested that neighbourhood access to food retailers affects the dietary patterns of local residents, but this hypothesis has not been adequately researched. We examine the association between neighbourhood accessibility to supermarkets and convenience stores and individuals' consumption of fruit and vegetables in New Zealand. METHODS: Using geographical information systems, travel times from the population-weighted centroid of each neighbourhood to the closest supermarket and convenience store were calculated for 38,350 neighbourhoods. These neighbourhood measures of accessibility were appended to the 2002-3 New Zealand Health Survey of 12,529 adults. RESULTS: The consumption of the recommended daily intake of fruit was not associated with living in a neighbourhood with better access to supermarkets or convenience stores. Similarly, access to supermarkets was not related to vegetable intake. However, individuals in the quartile of neighbourhoods with the best access to convenience stores had 25% (OR 0.75, 95% CI 0.60% to 0.93%) lower odds of eating the recommended vegetable intake compared to individuals in the base category (worst access). CONCLUSION: This study found little evidence that poor locational access to food retail provision is associated with lower fruit and vegetable consumption. However, before rejecting the common sense notion that neighbourhood access to fruit and vegetables affects personal consumption, research that measures fruit and vegetable access more precisely and directly is required.

A prospective randomised double-blind controlled trial evaluating the effect of trans-sacral magnetic stimulation in women with overactive bladder.

Overactive bladder (OAB) is a prevalent condition with 16% of adults having one or more symptoms that significantly affect quality of life. Transcutaneous electrical nerve stimulation and neuromodulators have had success in treating OAB but are expensive, invasive, and sometimes cumbersome. We developed an alternative neuromodulatory technique that involves electromagnetic stimulation of the sacral nerve roots with a portable electromagnetic device to produce trans-sacral stimulation of the S3 and S4 sacral nerve roots. The aim of this study was to evaluate the impact of this device on OAB symptoms in women with a prospectively randomised double-blind controlled study. Following a power analysis, women with symptoms of OAB were prospectively recruited with ethical approval for randomisation to an active treatment (n = 33) or placebo group (n = 30) in a double-blind trial. The patient, at home, used the belt device daily for 20 min over 12 weeks. Outcome measures included a 3-day voiding diary, 1 h pad test, visual analogue score (VAS) for symptom impact (0-100%), Kings Health Questionnaire (KHQ) and Australian Quality of Life questionnaire (AQOL) at baseline, 6 and 12 weeks. Overall, no difference was found between groups for any of the research questions. Specifically, we were unable to demonstrate any difference between the active and sham device groups in frequency, nocturia, urinary leakage, or quality of life, nor was there any evidence of a placebo effect. The quality of the data was high with the number of missing observations (especially for disease specific KHQ and general AQOL) being few. This attempt to promote trans-sacral electromagnetic neuromodulation with a specially created device was ineffective on the symptoms of OAB.

Injectable silicone biomaterial for fecal incontinence caused by internal anal sphincter dysfunction is effective.

PURPOSE: Fecal incontinence caused by a weak or disrupted internal anal sphincter is common but there has been no effective treatment. This prospective study evaluates the medium-term clinical effects of an injectable silicone biomaterial, PTP (Bioplastique), used to augment the internal anal sphincter. METHOD: Eighty-two patients (64 females; median age, 66 years) with severe fecal incontinence and a low anal resting pressure caused by internal anal sphincter dysfunction (defect, n = 11; intact, n = 71) were randomized to PTP injection into intersphincteric space and internal anal sphincter with (Group A, n = 42) or without (Group B, n = 40) guidance by endoanal ultrasound. Both groups were similar in terms of age, gender, past anorectal surgery, duration of follow-up (median, 6 months; range, 1-12 months), and baseline continence score. Sixty-two percent of Group A and 55 percent of Group B had prolonged pudendal nerve terminal motor latency. RESULTS: There was no significant complication. Two patients in Group A and four patients in Group B noted minor discomfort at injection sites. At one month postprocedure, endoanal ultrasound confirmed retention of silicone biomaterial without migration. In both groups, fecal continence was significantly improved by PTP implants 1 month after injection, but continued to improve significantly for up to 12 months in Group A and 6 months in Group B (P < 0.001). Improvement in fecal continence and maximum anal resting pressure was significantly greater in Group A, in whom injection was guided by endoanal ultrasound, than in Group B. At three months after injection, significantly more Group A patients than Group B patients achieved >50 percent improvement in Wexner's continence score (69 percent vs. 40 percent; P = 0.014). Ninety-three percent of Group A and 92 percent of Group B had >50 percent improvement in global quality of life scores (visual analog scale). At a median follow-up of 6 months, all domains of the fecal incontinence quality of life scale improved significantly in both groups; however, the physical function and mental health scores of Short Form-12 only improved in Group A. A prolonged pudendal nerve terminal motor latency had no effect on functional outcome in either group. CONCLUSION: Injection of silicone biomaterial provided a marked improvement in fecal continence and quality of life in patients with internal sphincter dysfunction, despite the presence of pudendal neuropathy.

Pharmacokinetics of bupivacaine enantiomers during interpleural infusion.

Interpleural infusions (24 hr) were given to 14 adults (29-81 yr) having surgery via right subcostal incisions. Patient-controlled analgesia with morphine was also available for 72 hours following surgery. An infusion of 0.25% bupivacaine with adrenaline 1/400,000 was commenced at 0.1 ml/kg/hr at the conclusion of surgery after an initial 20 ml bolus. The 24 hr cumulative morphine dose increased by 62% (P < 0.01) on the second postoperative day after the bupivacaine infusion was ceased, but the pain score did not change. There was no clinical evidence of bupivacaine toxicity although the maximum bupivacaine concentration ranged from 0.74-6.52 mg/l, mean 2.90 (SEM 0.44) mg/l and vascular uptake was rapid in two patients. The concentration of S-bupivacaine was consistently greater than R-bupivacaine (P < 0.05) and total body clearance was less. The unbound bupivacaine fraction also changed from 3.6% (SEM 0.6) at the start of the infusion to 2.0% (SEM 0.3) at 24 hr (P < 0.005). The total body clearance of each enantiomer was reduced during the 24 hours (P < 0.001). No relationship between pharmacokinetic parameters and weight, age or sex was found (P > 0.25 for each). Variation between patients was reduced when parameters were estimated for the free (unbound) bupivacaine (P < 0.001).

133 Xenon air contamination: a radiation safety aspect of pulmonary ventilation imaging.

Potential leakage of 133 xenon is a covert, insidious facet of ventilation imaging procedures. Airborne xenon is often unrecognized and, consequently, unmanaged. The presence of xenon in air is usually unrecognized because it is not sought! Ventilation imaging procedures should incorporate safeguards for the protection of people against the internal exposure of radiation due to the inadvertent release of xenon gas in the air. Protective measures include surveillance by area survey and air monitoring, maintenance of equipment, establishment and preservation of safety procedures, and management of airborne contamination. The need to follow the accepted health physics objective to reduce radiation exposure of humans to the lowest practicable level is reaffirmed!