Cost-effectiveness of routine transoesophageal echocardiography during cardiac surgery: a discrete-event simulation study.

BACKGROUND: The aim of this study was to simulate and compare the healthcare and economic outcomes associated with routine use of intraoperative transoesophageal echocardiography (TOE) in patients undergoing cardiac surgery with those associated with a scenario where TOE is not routinely used. METHODS: The impact of TOE on surgical decision-making was estimated through a systematic literature review. Individual short-term morbidity and mortality estimates were generated by application of the Society of Thoracic Surgeons risk calculator. Long-term event rates, unit costs, and utility weights were sourced from published literature and expert opinion. A discrete-event simulation model was then constructed to simulate both the in-hospital and post-discharge outcomes for patients undergoing cardiac surgery. Robustness of the base case results was examined through deterministic and probabilistic sensitivity analyses. An incremental cost-effectiveness ratio of €30 000 per quality-adjusted life-year gained was assumed to represent acceptable cost-effectiveness. RESULTS: Routine use of intraoperative TOE was associated with lower costs and higher benefits per patient, which indicates that use of TOE is a dominant strategy. The intervention resulted in the avoidance of 299 cardiac complications, 20 strokes, and 11 all-cause deaths per 10 000 patients. Routine intraoperative TOE was associated with an increased occurrence of bleeding owing to more valvular surgery and subsequent long-term anticoagulation. CONCLUSIONS: Routine intraoperative TOE is a cost-effective procedure for patients undergoing cardiac surgery, leading to lower overall costs. It was associated with a decrease in long-term complications including stroke, cardiac complications, and death, although there was a slight increase in extracranial bleeding events.

Vasoplegia after implantation of a continuous flow left ventricular assist device: incidence, outcomes and predictors.

BACKGROUND: Vasoplegia after routine cardiac surgery is associated with severe postoperative complications and increased mortality. It is also prevalent in patients undergoing implantation of pulsatile flow left ventricular assist devices (LVAD). However, less is known regarding vasoplegia after implantation of newer generations of continuous flow LVADs (cfLVAD). We aim to report the incidence, impact on outcome and predictors of vasoplegia in these patients. METHODS: Adult patients scheduled for primary cfLVAD implantation were enrolled into a derivation cohort (n = 118, 2006-2013) and a temporal validation cohort (n = 73, 2014-2016). Vasoplegia was defined taking into consideration low mean arterial pressure and/or low systemic vascular resistance, preserved cardiac index and high vasopressor support. Vasoplegia was considered after bypass and the first 48 h of ICU stay lasting at least three consecutive hours. This concept of vasoplegia was compared to older definitions reported in the literature in terms of the incidence of postoperative vasoplegia and its association with adverse outcomes. Logistic regression was used to identify independent predictors. Their ability to discriminate patients with vasoplegia was quantified by the area under the receiver operating characteristic curve (AUC). RESULTS: The incidence of vasoplegia was 33.1% using the unified definition of vasoplegia. Vasoplegia was associated with increased ICU length-of-stay (10.5 [6.9-20.8] vs 6.1 [4.6-10.4] p = 0.002), increased ICU-mortality (OR 5.8, 95% CI 1.9-18.2) and one-year-mortality (OR 3.9, 95% CI 1.5-10.2), and a higher incidence of renal failure (OR 4.3, 95% CI 1.8-10.4). Multivariable analysis identified previous cardiothoracic surgery, preoperative dopamine administration, preoperative bilirubin levels and preoperative creatinine clearance as independent preoperative predictors of vasoplegia. The resultant prediction model exhibited a good discriminative ability (AUC 0.80, 95% CI 0.71-0.89, p <  0.01). Temporal validation resulted in an AUC of 0.74 (95% CI 0.61-0.87, p <  0.01). CONCLUSIONS: In the era of the new generation of cfLVADs, vasoplegia remains a prevalent (33%) and critical condition with worse short-term outcomes and survival. We identified previous cardiothoracic surgery, preoperative treatment with dopamine, preoperative bilirubin levels and preoperative creatinine clearance as independent predictors.

Preoperative determinants of quality of life a year after coronary artery bypass grafting: a historical cohort study.

BACKGROUND: Health related quality of life (HRQL) is an important patient related outcome measure after cardiac surgery. Preoperative determinants for postoperative HRQL have not yet been identified, but could aid in preoperative decision making. The aim of this article is to identify associations between preoperative determinants and change in HRQL 1 year after coronary artery bypass grafting (CABG). METHODS: Single centre retrospective cohort study in 658 patients. Change in HRQL was defined as a decrease or increase of ≥5 points on the physical or mental domain of the Short Form 12 (SF-12) questionnaire. Patients were stratified in three groups according to worse, unchanged, or better HRQL. Multinomial logistic regression analysis was used to investigate the association between preoperative risk factors and postoperative change in HRQL. RESULTS: Physical HRQL improved in 22.8% of patients, did not change in 61.2% of patients and worsened in 16.0% of patients. Comorbidities associated with change in physical HRQL were a history of stroke, atrial fibrillation, vascular disease or pulmonary disease. Most important risk factor for change in physical HRQL was preoperative HRQL. Higher preoperative SF-12 score decreased the odds for worse physical HRQL and increased the odds for better physical HRQL. Mental HRQL improved in 49.8% of patients, remained unchanged in 34.5% of patients and worsened in 15.7% of patients. Preoperative HRQL was an important risk factor for a change in mental HRQL. Higher preoperative physical HRQL increased the odds for improved mental HRQL. Lower preoperative mental HRQL increased the odds for better mental HRQL. CONCLUSIONS: One year after CABG the majority of patients experiences equal or improved HRQL compared to before surgery. Most important preoperative risk factor for change in HRQL is preoperative HRQL.

Implementing Medical Technological Equipment in the OR: Factors for Successful Implementations.

Operating rooms (ORs) more and more evolve into high-tech environments with increasing pressure on finances, logistics, and a not be neglected impact on patient safety. Safe and cost-effective implementation of technological equipment in ORs is notoriously difficult to manage, specifically as generic implementation activities omit as hospitals have implemented local policies for implementations of technological equipment. The purpose of this study is to identify success factors for effective implementations of new technologies and technological equipment in ORs, based on a systematic literature review. We accessed ten databases and reviewed included articles. The search resulted in 1592 titles for review, and finally 37 articles were included in this review. We distinguish influencing factors and resulting factors based on the outcomes of this research. Six main categories of influencing factors on successful implementations of medical equipment in ORs were identified: "processes and activities," "staff," "communication," "project management," "technology," and "training." We identified a seventh category "performance" referring to resulting factors during implementations. We argue that aligning the identified influencing factors during implementation impacts the success, adaptation, and safe use of new technological equipment in the OR and thus the outcome of an implementation. The identified categories in literature are considered to be a baseline, to identify factors as elements of a generic holistic implementation model or protocol for new technological equipment in ORs.

Accuracy of remote continuous respiratory rate monitoring technologies intended for low care clinical settings: a prospective observational study.

PURPOSE: Altered respiratory rate (RR) has been identified as an important predictor of serious adverse events during hospitalization. Introduction of a well-tolerated continuous RR monitor could potentially reduce serious adverse events such as opioid-induced respiratory depression. The purpose of this study was to investigate the ability of different monitor devices to detect RR in low care clinical settings. METHODS: This was a prospective method-comparison study with a cross-sectional design. Thoracic impedance pneumography (IPG), frequency modulated continuous wave radar, and an acoustic breath sounds monitor were compared with the gold standard of capnography for their ability to detect RR in breaths per minute (breaths·min-1) in awake postoperative patients in the postanesthesia care unit. The Bland and Altman method for repeated measurements and mixed effect modelling was used to obtain bias and limits of agreement (LoA). Furthermore, the ability of the three devices to assist with correct treatment decisions was evaluated in Clarke Error Grids. RESULTS: Twenty patients were monitored for 1,203 min, with a median [interquartile range] of 61 [60-63] min per patient. The bias (98.9% LoA) were 0.1 (-7.9 to 7.9) breaths·min-1 for the acoustic monitor, -1.6 (-10.8 to 7.6) for the radar, and -1.9 (-13.1 to 9.2) for the IPG. The extent to which the monitors guided adequate or led to inadequate treatment decisions (determined by Clarke Error Grid analysis) differed significantly between the monitors (P = 0.011). Decisions were correct 96% of the time for acoustic, 95% of the time for radar, and 94% of the time for IPG monitoring devices. CONCLUSIONS: None of the studied devices (acoustic, IPG, and radar monitor) had LoA that were within our predefined (based on clinical judgement) limits of ± 2 breaths·min-1. The acoustic breath sound monitor predicted the correct treatment more often than the IPG and the radar device.

The association between aortic cross clamp time and postoperative morbidity and mortality in mitral valve repair: a retrospective cohort study.

BACKGROUND: The aim of this study was to estimate the association between aortic cross clamp time and postoperative morbidity and mortality in patients undergoing mitral valve repair. METHODS: A retrospective cohort study between 2006 and 2014 was performed as a single Center study in the University Medical Center Utrecht. In total 1007 patients who underwent mitral valve repair were included. The patients were divided into a group who underwent isolated mitral valve repair and a group who underwent mitral valve repair with concomitant intervention(s). The primary endpoint was a composite consisting of in-hospital mortality or postoperative major complications. RESULTS: In the isolated mitral valve group (N.=405), patients were significantly younger, healthier and had fewer complications (9.9%). Patients with concomitant intervention(s) had a twofold higher rate of postoperative complications and mortality (18.1%). After adjustment for confounding there was no association between aortic cross clamp time and the primary endpoint in both the isolated mitral valve group (odds ratio 1.04; 95% CI: 0.98-1.11) and the group with concomitant interventions (odds ratio 1.02; 95% CI: 0.97-1.06). CONCLUSIONS: In patients undergoing mitral valve repair surgery a longer aortic cross clamp time was not associated with postoperative complications and mortality. The higher postoperative morbidity and mortality in combined procedures appears to be due to a higher age, more comorbidities and an extra intervention rather than to the duration of aortic cross clamp time.

Typical rise and fall of troponin in (peri-procedural) myocardial infarction: A systematic review.

AIM: To identify the typical shape of the rise and fall curve of troponin (Tn) following the different types of myocardial infarction (MI). METHODS: We conducted a systematic search in PubMed and Embase including all studies which focused on the kinetics of Tn in MI type 1, type 4 and type 5. Tn levels were standardized using the 99(th) percentile, a pooled mean with 95%CI was calculated from the weighted means for each time point until 72 h. RESULTS: A total of 34 of the 2528 studies identified in the systematic search were included. The maximum peak level of the Tn was seen after 6 h after successful reperfusion of an acute MI, after 12 h for type 1 MI and after 72 h for type 5 MI. In type 1 MI there were additional smaller peaks at 1 h and at 24 h. After successful reperfusion of an acute MI there was a second peak at 24 h. There was not enough data available to analyze the Tn release after MI associated with percutaneous coronary intervention (type 4). CONCLUSION: The typical rise and fall of Tn is different for type 1 MI, successful reperfusion of an acute MI and type 5 MI, with different timing of the peak levels and different slopes of the fall phase.

Non-Invasive Continuous Respiratory Monitoring on General Hospital Wards: A Systematic Review.

BACKGROUND: Failure to recognize acute deterioration in hospitalized patients may contribute to cardiopulmonary arrest, unscheduled intensive care unit admission and increased mortality. PURPOSE: In this systematic review we aimed to determine whether continuous non-invasive respiratory monitoring improves early diagnosis of patient deterioration and reduces critical incidents on hospital wards. DATA SOURCES: Studies were retrieved from Medline, Embase, CINAHL, and the Cochrane library, searched from 1970 till October 25, 2014. STUDY SELECTION: Electronic databases were searched using keywords and corresponding synonyms 'ward', 'continuous', 'monitoring' and 'respiration'. Pediatric, fetal and animal studies were excluded. DATA EXTRACTION: Since no validated tool is currently available for diagnostic or intervention studies with continuous monitoring, methodological quality was assessed with a modified tool based on modified STARD, CONSORT, and TREND statements. DATA SYNTHESIS: Six intervention and five diagnostic studies were included, evaluating the use of eight different devices for continuous respiratory monitoring. Quantitative data synthesis was not possible because intervention, study design and outcomes differed considerably between studies. Outcomes estimates for the intervention studies ranged from RR 0.14 (0.03, 0.64) for cardiopulmonary resuscitation to RR 1.00 (0.41, 2.35) for unplanned ICU admission after introduction of continuous respiratory monitoring. LIMITATIONS: The methodological quality of most studies was moderate, e.g. 'before-after' designs, incomplete reporting of primary outcomes, and incomplete clinical implementation of the monitoring system. CONCLUSIONS: Based on the findings of this systematic review, implementation of routine continuous non-invasive respiratory monitoring on general hospital wards cannot yet be advocated as results are inconclusive, and methodological quality of the studies needs improvement. Future research in this area should focus on technology explicitly suitable for low care settings and tailored alarm and treatment algorithms.

Reporting critical incidents in a tertiary hospital: a historical cohort study of 110,310 procedures.

PURPOSE: Investigation of adverse events associated with anesthetic procedures is a method of quality control that identifies topics to improve clinical care and patient safety. Most research to date has been based on closed claim registries and anonymous reports which have specific limitations. Therefore, to evaluate a hospital's reporting system, the present study was designed to describe critical incidents that anesthesiologists voluntarily and non-anonymously reported through an anesthesia information management system. METHODS: This is a historical observational cohort study on patients (age > 18 yr) undergoing anesthetic procedures in a tertiary referral hospital. A 20-item list of complications, as developed by the Netherlands Society of Anesthesiologists, was prospectively completed for each procedure. All critical incidents registered in the anesthesia information management system were then reclassified into 95 different critical incidents in a reproducible way. RESULTS: There were 110,310 procedures performed in 65,985 patients, and after excluding 158 reports that did not depict a critical incident, 3,904 critical incidents in 3,807 (3.5%) anesthetic procedures remained. Technical difficulties with regional anesthesia (n = 445; 40 per 10,000 anesthetics; 95% confidence interval [CI], 36 to 44), hypotension (n = 432; 39 per 10,000 anesthetics; 95% CI, 35 to 43), and unexpected difficult intubation (n = 216; 20 per 10,000 anesthetics; 95% CI, 18 to 23) were the most frequently documented critical incidents. CONCLUSION: Accurate measurement and monitoring of critical incidents is crucial for patient safety. Despite the risk of underreporting and probable misclassification of manual reporting systems, our results give a comprehensive overview on the occurrence of voluntarily reported anesthesia-related critical incidents. This overview can direct development of a new reporting system and preventive strategies to decrease the future occurrence of critical incidents.

Nonelective surgery at night and in-hospital mortality: Prospective observational data from the European Surgical Outcomes Study.

BACKGROUND: Evidence suggests that sleep deprivation associated with night-time working may adversely affect performance resulting in a reduction in the safety of surgery and anaesthesia. OBJECTIVE: Our primary objective was to evaluate an association between nonelective night-time surgery and in-hospital mortality. We hypothesised that urgent surgery performed during the night was associated with higher in-hospital mortality and also an increase in the duration of hospital stay and the number of admissions to critical care. DESIGN: A prospective cohort study. This is a secondary analysis of a large database related to perioperative care and outcome (European Surgical Outcome Study). SETTING: Four hundred and ninety-eight hospitals in 28 European countries. PATIENTS: Men and women older than 16 years who underwent nonelective, noncardiac surgery were included according to time of the procedure. INTERVENTION: None. MAIN OUTCOME MEASURES: Primary outcome was in-hospital mortality; the secondary outcome was the duration of hospital stay and critical care admission. RESULTS: Eleven thousand two hundred and ninety patients undergoing urgent surgery were included in the analysis with 636 in-hospital deaths (5.6%). Crude mortality odds ratios (ORs) increased sequentially from daytime [426 deaths (5.3%)] to evening [150 deaths (6.0%), OR 1.14; 95% confidence interval 0.94 to 1.38] to night-time [60 deaths (8.3%), OR 1.62; 95% confidence interval 1.22 to 2.14]. Following adjustment for confounding factors, surgery during the evening (OR 1.09; 95% confidence interval 0.91 to 1.31) and night (OR 1.20; 95% confidence interval 0.9 to 1.6) was not associated with an increased risk of postoperative death. Admittance rate to an ICU increased sequentially from daytime [891 (11.1%)], to evening [347 (13.8%)] to night time [149 (20.6%)]. CONCLUSION: In patients undergoing nonelective urgent noncardiac surgery, in-hospital mortality was associated with well known risk factors related to patients and surgery, but we did not identify any relationship with the time of day at which the procedure was performed. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT01203605.

Implementation of the third universal definition of myocardial infarction after coronary artery bypass grafting: a survey study in Western Europe.

BACKGROUND: Diagnosing a postoperative myocardial infarction in patients undergoing coronary artery bypass grafting is challenging, as the normally used criteria are more difficult to interpret. The rate of implementation of the consensus-based new diagnostic criteria for postoperative myocardial infarction proposed by the third universal definition of myocardial infarction is unknown. Therefore, the primary objective of this study was to address the implementation of the third universal definition of postoperative myocardial infarction following coronary artery bypass grafting. METHODS AND RESULTS: We conducted a web-based survey by sending 4 waves of invitations via e-mail to cardiothoracic surgeons in 12 Western European countries. Of the 302 participating cardiothoracic specialists, from 182 different centers, 213 (71%) were aware that troponin is the preferred biomarker and 112 (37%) knew that using a cut-off level of >10 times the 99th percentile is recommended. Overall, 90 (30%) participants (strongly) agreed with implementation of this cut-off level in their clinical practice. Troponin was used in clinical practice by 149 (49%) of the participants. In total, 117 (89%) of the 131 participants with a local guideline confirmed ECG changes as a diagnostic criterion in that guideline. ST segmental changes (75, 64%) were used more often for diagnosing postoperative myocardial infarction than Q waves (64, 55%) or new left bundle branch blocks (34, 29%). CONCLUSIONS: Cardiac biomarkers and ECG changes were not used in concordance with the third universal definition, and only a minority had a positive attitude toward implementation of the proposed cut-off level for troponin in their clinical practice.

Capnography during deep sedation with propofol by nonanesthesiologists: a randomized controlled trial.

BACKGROUND: Propofol, a short-acting hypnotic drug, is increasingly administered by a diverse group of specialists (e.g., cardiologists, gastroenterologists) during diagnostic and therapeutic procedures. Standard monitoring during sedation comprises continuous pulse oximetry with visual assessment of the patient's breathing pattern. Because undetected hypoventilation is a common pathway for complications, capnographic monitoring of exhaled carbon dioxide has been advocated. We examined whether the use of capnography reduces the incidence of hypoxemia during nonanesthesiologist-administered propofol sedation in patients who did not receive supplemental oxygen routinely. METHODS: An open, stratified, randomized controlled trial was conducted in 427 healthy adult women during minor gynecology procedures in an outpatient clinic in the Netherlands. Patients were randomly assigned to receive either standard respiratory monitoring (standard care) or standard respiratory monitoring combined with capnography (capnography group). To replicate usual clinical practice, capnography monitoring was performed by the same medical team that provided sedation. The primary end point was the incidence of hypoxemia, defined as oxygen saturations <91%. RESULTS: From April 2010 to January 2011, 427 patients were enrolled. In the capnography group, 206 patients and in the standard care group, 209 patients were analyzed. The percentage of patients with a hypoxemic episode was 25.7% (53 of 206) in the capnography group and 24.9% (52 of 209) in the standard care group, resulting in an absolute difference of 0.8% (-7.5 to 9.2%). CONCLUSIONS: We were unable to confirm an additive role for capnography in preventing hypoxemia during elective nonanesthesiologist-administered propofol (monotherapy) sedation in healthy women in whom supplemental oxygen is not routinely administered. Based on the confidence interval, the benefit of adding capnography is at most an absolute hypoxemia reduction of 7.5%, suggesting that adding it in this practice setting to the routine monitoring strategy does not necessarily improve patient safety in daily practice.

From accuracy to patient outcome and cost-effectiveness evaluations of diagnostic tests and biomarkers: an exemplary modelling study.

BACKGROUND: Proper evaluation of new diagnostic tests is required to reduce overutilization and to limit potential negative health effects and costs related to testing. A decision analytic modelling approach may be worthwhile when a diagnostic randomized controlled trial is not feasible. We demonstrate this by assessing the cost-effectiveness of modified transesophageal echocardiography (TEE) compared with manual palpation for the detection of atherosclerosis in the ascending aorta. METHODS: Based on a previous diagnostic accuracy study, actual Dutch reimbursement data, and evidence from literature we developed a Markov decision analytic model. Cost-effectiveness of modified TEE was assessed for a life time horizon and a health care perspective. Prevalence rates of atherosclerosis were age-dependent and low as well as high rates were applied. Probabilistic sensitivity analysis was applied. RESULTS: The model synthesized all available evidence on the risk of stroke in cardiac surgery patients. The modified TEE strategy consistently resulted in more adapted surgical procedures and, hence, a lower risk of stroke and a slightly higher number of life-years. With 10% prevalence of atherosclerosis the incremental cost-effectiveness ratio was € 4,651 and € 481 per quality-adjusted life year in 55-year-old men and women, respectively. In all patients aged 65 years or older the modified TEE strategy was cost saving and resulted in additional health benefits. CONCLUSIONS: Decision analytic modelling to assess the cost-effectiveness of a new diagnostic test based on characteristics, costs and effects of the test itself and of the subsequent treatment options is both feasible and valuable. Our case study on modified TEE suggests that it may reduce the risk of stroke in cardiac surgery patients older than 55 years at acceptable cost-effectiveness levels.

Comparison of approaches to estimate confidence intervals of post-test probabilities of diagnostic test results in a nested case-control study.

BACKGROUND: Nested case-control studies become increasingly popular as they can be very efficient for quantifying the diagnostic accuracy of costly or invasive tests or (bio)markers. However, they do not allow for direct estimation of the test's predictive values or post-test probabilities, let alone for their confidence intervals (CIs). Correct estimates of the predictive values itself can easily be obtained using a simple correction by the (inverse) sampling fractions of the cases and controls. But using this correction to estimate the corresponding standard error (SE), falsely increases the number of patients that are actually studied, yielding too small CIs. We compared different approaches for estimating the SE and thus CI of predictive values or post-test probabilities of diagnostic test results in a nested case-control study. METHODS: We created datasets based on a large, previously published diagnostic study on 2 different tests (D-dimer test and calf difference test) with a nested case-control design. We compared six different approaches; the approaches were: 1. the standard formula for the SE of a proportion, 2. adaptation of the standard formula with the sampling fraction, 3. A bootstrap procedure, 4. A approach, which uses the sensitivity, the specificity and the prevalence, 5. Weighted logistic regression, and 6. Approach 4 on the log odds scale. The approaches were compared with respect to coverage of the CI and CI-width. RESULTS: The bootstrap procedure (approach 3) showed good coverage and relatively small CI widths. Approaches 4 and 6 showed some undercoverage, particularly for the D-dimer test with frequent positive results (positive results around 70%). Approaches 1, 2 and 5 showed clear overcoverage at low prevalences of 0.05 and 0.1 in the cohorts for all case-control ratios. CONCLUSION: The results from our study suggest that a bootstrap procedure is necessary to assess the confidence interval for the predictive values or post-test probabilities of diagnostic tests results in studies using a nested case-control design.