350 research outputs found
Three years of Extreme Physiology & Medicine
No full text© 2015 Grocott and Montgomery. This article is distributed under the terms of the Creative Commons Attribution 4.0 Interna‑
tional License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in
any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Com‑
mons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecom‑
mons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated
Survival after postoperative morbidity: a longitudinal observational cohort study.
No full textBACKGROUND: Previous studies have suggested that there may be long-term harm associated with postoperative complications. Uncertainty exists however, because of the need for risk adjustment and inconsistent definitions of postoperative morbidity. METHODS: We did a longitudinal observational cohort study of patients undergoing major surgery. Case-mix adjustment was applied and morbidity was recorded using a validated outcome measure. Cox proportional hazards modelling using time-dependent covariates was used to measure the independent relationship between prolonged postoperative morbidity and longer term survival. RESULTS: Data were analysed for 1362 patients. The median length of stay was 9 days and the median follow-up time was 6.5 yr. Independent of perioperative risk, postoperative neurological morbidity (prevalence 2.9%) was associated with a relative hazard for long-term mortality of 2.00 [P=0.001; 95% confidence interval (CI) 1.32-3.04]. Prolonged postoperative morbidity (prevalence 15.6%) conferred a relative hazard for death in the first 12 months after surgery of 3.51 (P<0.001; 95% CI 2.28-5.42) and for the next 2 yr of 2.44 (P<0.001; 95% CI 1.62-3.65), returning to baseline thereafter. CONCLUSIONS: Prolonged morbidity after surgery is associated with a risk of premature death for a longer duration than perhaps is commonly thought; however, this risk falls with time. We suggest that prolonged postoperative morbidity measured in this way may be a valid indicator of the quality of surgical healthcare. Our findings reinforce the importance of research and quality improvement initiatives aimed at reducing the duration and severity of postoperative complications
Variation of Saturn's UV aurora with SKR phase
No full textpeer reviewedIt is well known that a wide range of kronian magnetospheric phenomena, including the Saturn kilometric radiation (SKR), exhibit oscillations near the planetary rotation period. However, although the SKR is believed to be generated by unstable auroral electrons, no connection has been established to date between diurnal SKR modulations and UV auroral power. We use an empirical SKR phase determined from Cassini observations to order the 'quiet time' total emitted UV auroral power as observed by the Hubble Space Telescope in programs during the interval 2005-2009. Our results indicate that both the northern and southern UV powers are dependent on SKR phase, varying diurnally by factors of similar to 3. We also show that the UV variation originates principally from the morning half of the oval, consistent with previous observations of the SKR sources. Citation: Nichols, J. D., B. Cecconi, J. T. Clarke, S. W. H. Cowley, J.-C. Gerard, A. Grocott, D. Grodent, L. Lamy, and P. Zarka (2010), Variation of Saturn's UV aurora with SKR phase, Geophys. Res. Lett., 37, L15102, doi: 10.1029/2010GL044057
Surfactant phospholipid kinetics in patients with Acute Respiratory Distress Syndrome (ARDS)
No full textIntroduction and Aims ARDS is a significant health burden. Mortality still remains high between 30–50%. Surfactant is a mixture of phospholipids and proteins. Phosphatidylcholines (PC) account for 80% of total phospholipids. PC16:0/16:0 is the main PC with surface tension reducing characteristics. Surfactant abnormalities are well recognised in patients with ARDS However, replacement strategies remain unhelpful in improving mortality. Existing diagnostic definitions fail to identify a homogeneous population and this lack of phenotyping of patients according to surfactant biology may in part explain the absence of therapeutic benefit. The aims of this study are to assess surfactant PC kinetics by the incorporation of methyl-D9-choline in patients with ARDS.
Methods ARDS patients were identified according to American European Consensus Conference (AECC) criteria. Patients were infused with 3.6mg/kg methyl-D9-choline. Small volume bronchoalveolar lavages were performed via a fibre optic bronchoscope at serial time points. Healthy volunteers were used as controls. The phospholipid fraction was extracted and analysed by triple quadrupole electrospray ionisation mass spectrometry.
Results Ten patients and nine healthy controls were recruited. The endogenous PC composition consisted primarily of PC16:0/16:0, PC16:0/18:1 and PC18:0/18:2. There was significant reduction in the relative proportion of endogenous PC16:0/16:0 in patients. Compared to healthy controls, newly synthesised deuteriated PC16:0/16:0 was much lower in patients (26%) than controls (47%).
Total surfactant PC D9-incorporation was linear until 48 hours (0.019%/h, r2=0.9734, P<0.05) and reached its maximum at 48 hours (0.93±0.15%). Steady state of incorporation was achieved between 48–96 hours. There was ∼80% increase in the fractional D9 labelling in patients at 48 hours compared to healthy controls.
Total plasma PC D9-incorporation was linear until 24 hours (0.032%/h, r2=0.9825, P<0.05) and reached its maximum (0.755±0.056%) at 24 hours. Linear decline in enrichment was noted after 24 hours at a rate of 0.003% per hour (r2=0.9915, P<0.05). The total surfactant PC D9-incorporation was much higher for patients at 24 hours and 48 hours reflecting increased synthetic rate.
Conclusions By labelling surfactant PC precursors, it is possible to study surfactant kinetics in patients with ARDS. The methodology may be utilised to phenotype patients according to alveolar surfactant kinetics prior to replacement strategies
Standardizing end points in perioperative trials: Towards a core and extended outcome set
No full textCOMPAC-StEP Group members include: J. Bartoszko, W. S. Beattie, R. Bellomo, D. Buggy, L. Cabrini, J. Canet, T. Cook, D. J. Cooper, T. Corcoran, P. J. Devereaux, R. Eckenhoff, L. Evered, T. J. Gan, T. Gin, H. Grocott, G. Haller, S. Howell, M. Jayarajah, C. Kalkman, K. Karkouti, B. Kavanagh, A. Klein, G. Landoni, K. Leslie, D. R. McIlroy, D. Mazer, A. Moller, M. Mythen, M. Neuman, M. Neuman, R. Pearse, P. Peyton, J. Prowle, T. Richards, D. A. Scott, D. Sessler, A. Shaw, T. Short, M. Shulman, B. Silbert, M. Singer, J. R. Sneyd, D. Story, D. van Dijk, and W. van Klei
Bronchoalveolar lavage, tracheal wash and induced sputum surfactant phospholipid kinetics from healthy volunteers
No full textIntroduction and Aims: Pulmonary surfactant is a complex mixture of lipoproteins synthesised and secreted by alveolar type II cells. The assessment of surfactant synthetic function and metabolism may provide essential information in disease states characterised by surfactant dysfunction. Airway surfactant is thought to be of alveolar origin. However, surfactant kinetics from airway secretions may vary from alveolar surfactant. Stable isotope labelling of surfactant precursors enables dynamic mapping of surfactant PC molecular species. This study aimed to compare three surfactant recovery methods [bronchoalveolar lavage (BAL), tracheal wash (TW) and induced sputum (IS)] to assess surfactant PC kinetics in healthy adults. Surfactant phosphatidylcholine (PC) is synthesised de novo from choline via CDP-choline pathway. By labelling choline with deuterium, a naturally occurring isotope of hydrogen, it is possible to assess surfactant PC synthesis and metabolism in humans.
Methods: Healthy human volunteers had an infusion of methyl-D9-choline-chloride [3.6mg/kg] for 3 hours. BAL and TW specimens were taken at 24 and 48 hours and induced sputum samples were taken at 0, 8, 24, 48 and 96 hours after choline infusion. The lipid fraction was extracted with chloroform and methanol. The samples were analysed by triple quadrupole electro spray ionisation mass spectrometer (ESI/MS). The results are expressed in mean (+/–standard error of mean).
Results: Ten healthy volunteers were recruited. The endogenous PC composition from BAL and TW were similar. The newly synthesised PC fraction mirrored the endogenous composition at 48 hours for both BAL and TW IS PC composition and D9 labelled PC fraction was variable. The total PC D9-incorporation at 48 hours was higher than 24 hours for BAL (0.55±0.04%), TW (0.56±0.04%) and IS (0.58±0.06). PC16:0/16:0 D9-incorporation had significant correlation for BAL and TW (r2=0.8201, P<0.05).
Conclusions: Isotope labelling of choline using ESI/MS analytical method, it is possible to assess surfactant PC metabolism. The tracheal aspirate is an alternative technique to assess surfactant metabolism in patients otherwise unable to tolerate invasive bronchoscopy. This methodology may be utilised to assess surfactant synthetic function in patients with acute lung injury
Dynamic subauroral ionospheric electric fields observed by the Falkland Islands radar during the course of a geomagnetic storm
No full textWe present an analysis of ionospheric electric field data observed during a geomagnetic
storm by the recently deployed HF radar located on the Falkland Islands. On 3 August
2010 at ∼1800 UT evidence of the onset of a geomagnetic storm was observed in ground
magnetometer data in the form of a decrease in the Sym‐H index of ∼100 nT. The
main phase of the storm was observed to last ∼24 hours before a gradual recovery lasting
∼3 days. On 4 August, during the peak magnetic disturbance of the storm, a high velocity
(>1000 m s−1) channel of ionospheric plasma flow, which we interpret as a subauroral
ion drift (SAID), located between 53° and 58° magnetic south and lasting ∼6.5 hours, was
observed by the Falkland Islands radar in the pre‐midnight sector. Coincident flow data
from the DMSP satellites and the magnetically near‐conjugate northern hemisphere
Blackstone HF radar reveal that the SAID was embedded within the broader subauroral
polarization streams (SAPS). DMSP particle data indicate that the SAID location closely
followed the equatorward edge of the auroral electron precipitation boundary, while
remaining generally poleward of the equatorward boundary of the ion precipitation. The
latitude of the SAID varied throughout the interval on similar timescales to variations in
the interplanetary magnetic field and auroral activity, while variations in its velocity were
more closely related to ring current dynamics. These results are consistent with SAID
electric fields being generated by localized charge separation in the partial ring current, but
suggest that their location is more strongly governed by solar wind driving and associated
large‐scale magnetospheric dynamics
Preoperative aerobic exercise training in elective intra-cavity surgery: a systematic review
No full textReduced physical fitness is associated with increased risk of complications after intra-cavity surgery. Aerobic exercise training interventions improve physical fitness in clinical populations. However, it is unclear whether implementing a preoperative aerobic exercise training intervention improves outcome after intra-cavity surgery. We conducted a systematic review (Embase and PubMed, to April 2011) to address the question: does preoperative aerobic exercise training in intra-cavity surgery result in improved postoperative clinical outcomes? Secondary objectives were to describe the effect of such an intervention on physical fitness and health-related quality of life (HRQL) and report feasibility, safety, and cost-effectiveness. Ten studies were identified from 2443 candidate abstracts. Eight studies were small (<100 patients) and all were single centre. Seven studies reported clinical outcomes. Two studies were controlled trials and two used a sham intervention group. One study in cardiac surgery demonstrated reduced postoperative hospital and intensive care length of stay in the intervention group. Eight studies showed improvement in ?1 measure of physical fitness after the intervention. HRQL was reported in five studies; three showed improved HRQL after the intervention. The frequency, duration, and intensities of the exercise interventions varied across the studies. Adherence to exercise interventions was good. Two exercise-related adverse events (transient hypotension) were reported. Evidence for improved postoperative clinical outcome after preoperative aerobic exercise training interventions is limited. However, preoperative aerobic exercise training seems to be generally effective in improving physical fitness in patients awaiting intra-cavity surgery and appears to be feasible and safe
Peri-operative care pathways: re-engineering care to achieve the ‘triple aim’
No full textSummary: Elective surgical pathways offer a particular opportunity to plan radical change in the way care is delivered, based on patient need rather than provider convenience. Peri-operative pathway redesign enables improved patient experience of care (including quality and satisfaction), population/public health, and healthcare value (outcome per unit of currency). Among physicians with the skills to work within peri-operative medicine, anaesthetists are well positioned to lead the re-engineering of such pathways. Re-engineered pre-operative pathways open up opportunities for intervention before surgery including shared decision-making, comorbidity management and collaborative behavioural change. Individualised, risk-adapted, intra-operative interventions will drive more reliable and consistent care. Risk-adapted postoperative care, particularly around transitions of care, has a significant role in improving value through peri-operative medicine. Improved integration with primary care providers offers the potential for minimising errors around transitions of care before and after surgery, as well as maximising opportunities for population health interventions, including lifestyle modification (e.g. activity/exercise, smoking and/or alcohol cessation), pain management and sleep medicine. Systematic data collection focused on quality improvement is essential to drive continuous clinical improvement and will be enabled by technological development in predictive analytics, systems modelling and artificial intelligence.</p
sj-docx-1-inc-10.1177_17511437231192385 – Supplemental material for The effect of conservative oxygen therapy on mortality in adult critically ill patients: A systematic review and meta-analysis of randomised controlled trials
No full textSupplemental material, sj-docx-1-inc-10.1177_17511437231192385 for The effect of conservative oxygen therapy on mortality in adult critically ill patients: A systematic review and meta-analysis of randomised controlled trials by Daniel S Martin, Helen T Mckenna, Kathryn M Rowan, Doug W Gould, Paul R Mouncey, Michael PW Grocott and David A Harrison in Journal of the Intensive Care Society</p
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