Investigating inhibition of return with converging interdisciplinary methods

This dissertation investigates inhibition of return (IOR) as two forms of inhibitory cueing effects operating on spatially uninformative visual stimuli (i.e., cues): an output form of IOR that is generated when saccades are permitted, and an input form of IOR that arises when saccades are not allowed. Using paradigms adapted from Posner’s (1980) spatial cueing task, our first set of experiments in Chapter 2 attempts to dissociate the two forms of IOR by incorporating an incompatible response paradigm that requires either saccadic or manual keypress responses to targets. This design allowed us to examine separately the input form of IOR at the stimulus level versus the output form that is response related. The event-related potential (ERP) study in Chapter 3 builds upon the previous paradigm but uses saccades to cues to activate the oculomotor system. The activation of the oculomotor system allowed us to probe the neural mechanisms underlying the inhibitory cueing effects that are usually exhibited and studied in terms of behavioural response times. By manipulating stimulus-response compatibility in combination with activation or suppression of the oculomotor system in Chapters 2 and 3, we showed that the input form of IOR can be observed behaviourally when the oculomotor system is supressed. However, since we are ultimately looking for evidence of output-based IOR, which we have not been able to show with the anti-localisation paradigm, we decided that a change in direction was necessary. Chapters 4 and 5 present a shift in focus towards investigating modulations of behavioural cueing effects associated with the inclusion of non-targets (i.e., distractors) in a discrimination-localisation task. Our time-course study laid out the development of IOR in a distractor paradigm, and the results indicate that when distractors are present, oculomotor IOR starts early and slowly decays, whereas sensory-based IOR emerges later but decays relatively faster. The visually balanced ERP experiment in Chapter 6 allowed us to study the N2pc component as a neurophysiological marker of the output form of IOR while the oculomotor system is activated. We provide convincing evidence for behavioural IOR despite the presence of distractors, although ERP results are less clear cut. This dissertation provides converging evidence in support of an input based sensory/attentional IOR that is distinct from output based oculomotor IOR

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

Investigating inhibition of return with converging interdisciplinary methods

This dissertation investigates inhibition of return (IOR) as two forms of inhibitory cueing effects operating on spatially uninformative visual stimuli (i.e., cues): an output form of IOR that is generated when saccades are permitted, and an input form of IOR that arises when saccades are not allowed. Using paradigms adapted from Posner’s (1980) spatial cueing task, our first set of experiments in Chapter 2 attempts to dissociate the two forms of IOR by incorporating an incompatible response paradigm that requires either saccadic or manual keypress responses to targets. This design allowed us to examine separately the input form of IOR at the stimulus level versus the output form that is response related. The event-related potential (ERP) study in Chapter 3 builds upon the previous paradigm but uses saccades to cues to activate the oculomotor system. The activation of the oculomotor system allowed us to probe the neural mechanisms underlying the inhibitory cueing effects that are usually exhibited and studied in terms of behavioural response times. By manipulating stimulus-response compatibility in combination with activation or suppression of the oculomotor system in Chapters 2 and 3, we showed that the input form of IOR can be observed behaviourally when the oculomotor system is supressed. However, since we are ultimately looking for evidence of output-based IOR, which we have not been able to show with the anti-localisation paradigm, we decided that a change in direction was necessary. Chapters 4 and 5 present a shift in focus towards investigating modulations of behavioural cueing effects associated with the inclusion of non-targets (i.e., distractors) in a discrimination-localisation task. Our time-course study laid out the development of IOR in a distractor paradigm, and the results indicate that when distractors are present, oculomotor IOR starts early and slowly decays, whereas sensory-based IOR emerges later but decays relatively faster. The visually balanced ERP experiment in Chapter 6 allowed us to study the N2pc component as a neurophysiological marker of the output form of IOR while the oculomotor system is activated. We provide convincing evidence for behavioural IOR despite the presence of distractors, although ERP results are less clear cut. This dissertation provides converging evidence in support of an input based sensory/attentional IOR that is distinct from output based oculomotor IOR

Prospective observational cohort study on grading the severity of postoperative complications in global surgery research

Background The Clavien–Dindo classification is perhaps the most widely used approach for reporting postoperative complications in clinical trials. This system classifies complication severity by the treatment provided. However, it is unclear whether the Clavien–Dindo system can be used internationally in studies across differing healthcare systems in high- (HICs) and low- and middle-income countries (LMICs). Methods This was a secondary analysis of the International Surgical Outcomes Study (ISOS), a prospective observational cohort study of elective surgery in adults. Data collection occurred over a 7-day period. Severity of complications was graded using Clavien–Dindo and the simpler ISOS grading (mild, moderate or severe, based on guided investigator judgement). Severity grading was compared using the intraclass correlation coefficient (ICC). Data are presented as frequencies and ICC values (with 95 per cent c.i.). The analysis was stratified by income status of the country, comparing HICs with LMICs. Results A total of 44 814 patients were recruited from 474 hospitals in 27 countries (19 HICs and 8 LMICs). Some 7508 patients (16·8 per cent) experienced at least one postoperative complication, equivalent to 11 664 complications in total. Using the ISOS classification, 5504 of 11 664 complications (47·2 per cent) were graded as mild, 4244 (36·4 per cent) as moderate and 1916 (16·4 per cent) as severe. Using Clavien–Dindo, 6781 of 11 664 complications (58·1 per cent) were graded as I or II, 1740 (14·9 per cent) as III, 2408 (20·6 per cent) as IV and 735 (6·3 per cent) as V. Agreement between classification systems was poor overall (ICC 0·41, 95 per cent c.i. 0·20 to 0·55), and in LMICs (ICC 0·23, 0·05 to 0·38) and HICs (ICC 0·46, 0·25 to 0·59). Conclusion Caution is recommended when using a treatment approach to grade complications in global surgery studies, as this may introduce bias unintentionally

Critical care admission following elective surgery was not associated with survival benefit: prospective analysis of data from 27 countries

This was an investigator initiated study funded by Nestle Health Sciences through an unrestricted research grant, and by a National Institute for Health Research (UK) Professorship held by RP. The study was sponsored by Queen Mary University of London

The surgical safety checklist and patient outcomes after surgery: a prospective observational cohort study, systematic review and meta-analysis

© 2017 British Journal of Anaesthesia Background: The surgical safety checklist is widely used to improve the quality of perioperative care. However, clinicians continue to debate the clinical effectiveness of this tool. Methods: Prospective analysis of data from the International Surgical Outcomes Study (ISOS), an international observational study of elective in-patient surgery, accompanied by a systematic review and meta-analysis of published literature. The exposure was surgical safety checklist use. The primary outcome was in-hospital mortality and the secondary outcome was postoperative complications. In the ISOS cohort, a multivariable multi-level generalized linear model was used to test associations. To further contextualise these findings, we included the results from the ISOS cohort in a meta-analysis. Results are reported as odds ratios (OR) with 95% confidence intervals. Results: We included 44 814 patients from 497 hospitals in 27 countries in the ISOS analysis. There were 40 245 (89.8%) patients exposed to the checklist, whilst 7508 (16.8%) sustained ≥1 postoperative complications and 207 (0.5%) died before hospital discharge. Checklist exposure was associated with reduced mortality [odds ratio (OR) 0.49 (0.32–0.77); P\u3c0.01], but no difference in complication rates [OR 1.02 (0.88–1.19); P=0.75]. In a systematic review, we screened 3732 records and identified 11 eligible studies of 453 292 patients including the ISOS cohort. Checklist exposure was associated with both reduced postoperative mortality [OR 0.75 (0.62–0.92); P\u3c0.01; I2=87%] and reduced complication rates [OR 0.73 (0.61–0.88); P\u3c0.01; I2=89%). Conclusions: Patients exposed to a surgical safety checklist experience better postoperative outcomes, but this could simply reflect wider quality of care in hospitals where checklist use is routine

Kuluttajabarometri maakunnittain 2000, 2. neljännes

Suomen virallinen tilasto (SVT

Use of failure-to-rescue to identify international variation in postoperative care in low-, middle- and high-income countries: a 7-day cohort study of elective surgery

This was an investigator-initiated study funded by Nestle Health Sciences through an unrestricted research grant and by a National Institute for Health Research (UK) Professorship held by R.P. The study was sponsored by Queen Mary University of London