Associations Between Socioeconomic Status, Patient Risk, and Short-Term Intensive Care Outcomes.

OBJECTIVES: To investigate the association of socioeconomic status as measured by the average socioeconomic status of the area where a person resides on short-term mortality in adults admitted to an ICU in Queensland, Australia. DESIGN: Secondary data analysis using de-identified data from the Australian and New Zealand Intensive Care Society Centre for Outcome and Resource Evaluation linked to the publicly available area-level Index of Relative Socioeconomic Advantage and Disadvantage from the Australian Bureau of Statistics. SETTING: Adult ICUs from 35 hospitals in Queensland, Australia, from 2006 to 2015. PATIENTS: A total of 218,462 patient admissions. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The outcome measure was inhospital mortality. The main study variable was decile of Index of Relative Socioeconomic Advantage and Disadvantage. The overall crude inhospital mortality was 7.8%; 9% in the most disadvantaged decile and 6.9% in the most advantaged decile (p < 0.001). Increasing socioeconomic disadvantage was associated with increasing severity of illness as measured by Acute Physiology and Chronic Health Evaluation III score, admission with a diagnosis of sepsis or trauma, cardiac, respiratory, renal, and hepatic comorbidities, and remote location. Increasing socioeconomic advantage was associated with elective surgical admission, hematological and oncology comorbidities, and admission to a private hospital (all p < 0.001). After excluding patients admitted after elective surgery, in the remaining 106,843 patients, the inhospital mortality was 13.6%, 13.3% in the most disadvantaged, and 14.1% in the most advantaged. There was no trend in mortality across deciles of socioeconomic status after excluding elective surgery patients. In the logistic regression model adjusting for severity of illness and diagnosis, there was no statistically significant difference in the odds ratio of inhospital mortality for the most disadvantaged decile compared with other deciles. This suggests variables used for risk adjustment may lie on the causal pathway between socioeconomic status and outcome in ICU patients. CONCLUSIONS: Socioeconomic status as defined as Index of Relative Socioeconomic Advantage and Disadvantage of the area in which a patient lives was associated with ICU admission diagnosis, comorbidities, severity of illness, and crude inhospital mortality in this study. Socioeconomic status was not associated with inhospital mortality after excluding elective surgical patients or when adjusted for severity of illness and admission diagnosis. Commonly used measures for risk adjustment in intensive care improve understanding of the pathway between socioeconomic status and outcomes.

Measuring the quality of perioperative care in cardiac surgery.

Quality of care is of increasing importance in health and surgical care. In order to maintain and improve quality, we must be able to measure it and identify variation. In this narrative review, we aim to identify measures used in the assessment of quality of care in cardiac surgery and to evaluate their utility. The electronic databases Pubmed/MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Database of Systematic Reviews, and CINAHL were searched for original published studies using the terms 'cardiac surgery' and 'quality or outcome or process or structure' as either keywords in the title or text or MeSH terms. Secondary searches and identification of references from original articles were carried out. We found a total of 54 original articles evaluating measurements of quality. While structure, process, and outcome indicators remain the mainstay of quality measurement, new and innovative methods of risk assessment have improved reliability and discrimination. Continuous assessment provides a promising method of both maintaining and improving quality of care. Future studies should focus on long-term and patient-centred outcomes, such as quality-of-life measures.

Protein-bound drugs are prone to sequestration in the extracorporeal membrane oxygenation circuit: results from an ex vivo study.

INTRODUCTION: Vital drugs may be degraded or sequestered in extracorporeal membrane oxygenation (ECMO) circuits, with lipophilic drugs considered to be particularly vulnerable. However, the circuit effects on protein-bound drugs have not been fully elucidated. The aim of this experimental study was to investigate the influence of plasma protein binding on drug disposition in ex vivo ECMO circuits. METHODS: Four identical ECMO circuits comprising centrifugal pumps and polymethylpentene oxygenators and were used. The circuits were primed with crystalloid, albumin and fresh human whole blood and maintained at a physiological pH and temperature for 24 hours. After baseline sampling, known quantities of study drugs (ceftriaxone, ciprofloxacin, linezolid, fluconazole, caspofungin and thiopentone) were injected into the circuit to achieve therapeutic concentrations. Equivalent doses of these drugs were also injected into four polypropylene jars containing fresh human whole blood for drug stability testing. Serial blood samples were collected from the controls and the ECMO circuits over 24 hours, and the concentrations of the study drugs were quantified using validated chromatographic assays. A regression model was constructed to examine the relationship between circuit drug recovery as the dependent variable and protein binding and partition coefficient (a measure of lipophilicity) as explanatory variables. RESULTS: Four hundred eighty samples were analysed. There was no significant loss of any study drugs in the controls over 24 hours. The average drug recoveries from the ECMO circuits at 24 hours were as follows: ciprofloxacin 96%, linezolid 91%, fluconazole 91%, ceftriaxone 80%, caspofungin 56% and thiopentone 12%. There was a significant reduction of ceftriaxone (P = 0.01), caspofungin (P = 0.01) and thiopentone (P = 0.008) concentrations in the ECMO circuit at 24 hours. Both protein binding and partition coefficient were highly significant, with the model possessing a high coefficient of determination (R (2) = 0.88, P <0.001). CONCLUSIONS: Recovery of the highly protein-bound drugs ceftriaxone, caspofungin and thiopentone was significantly lower in the ECMO circuits at 24 hours. For drugs with similar lipophilicity, the extent of protein binding may determine circuit drug loss. Future clinical population pharmacokinetic studies should initially be focused on drugs with greater lipophilicity and protein binding, and therapeutic drug monitoring should be strongly considered with the use of such drugs.

Acute Risk Change for Cardiothoracic Admissions to Intensive Care (ARCTIC index): a new measure of quality in cardiac surgery.

BACKGROUND: Quality of cardiac surgical care may vary between institutions. Mortality is low and large numbers are required to discriminate between hospitals. Measures other than mortality may provide better comparisons. OBJECTIVES: To develop and assess the Acute Risk Change for Cardiothoracic Admissions to Intensive Care (ARCTIC) index, a new performance measure for cardiothoracic admissions to intensive care units (ICUs). METHODS: The Australian and New Zealand Society of Cardiac and Thoracic Surgeons database and Australian and New Zealand Intensive Care Society Adult Patient Database were linked. Logistic regression was used to generate a predicted risk of death first from preoperative data using the previously validated Allprocscore and second on admission to an ICU using Acute Physiology and Chronic Health Evaluation III score. Change in risk as a percentage (ARCTIC) was calculated for each patient. The validity of ARCTIC as a marker of quality was assessed by comparison with intraoperative variables and postoperative morbidity markers. RESULTS: Sixteen thousand six hundred eighty-seven patients at 21 hospitals from 2008 to 2011 were matched. An increase in ARCTIC score was associated with prolonged cardiopulmonary bypass time (P = .001), intraoperative blood product transfusion (P < .001), reoperation (P < .0001), postoperative renal failure (P < .0001), prolonged ventilation (P < .0001), and stroke (P = .001). CONCLUSIONS: The ARCTIC index is associated with known markers of perioperative performance and postoperative morbidity. It may be used as an overall marker of quality for cardiac surgery. Further work is required to assess ARCTIC as a method to discriminate between cardiac surgical units.

Extracorporeal life support devices and strategies for management of acute cardiorespiratory failure in adult patients: a comprehensive review.

Evolution of extracorporeal life support (ECLS) technology has added a new dimension to the intensive care management of acute cardiac and/or respiratory failure in adult patients who fail conventional treatment. ECLS also complements cardiac surgical and cardiology procedures, implantation of long-term mechanical cardiac assist devices, heart and lung transplantation and cardiopulmonary resuscitation. Available ECLS therapies provide a range of options to the multidisciplinary teams who are involved in the time-critical care of these complex patients. While venovenous extracorporeal membrane oxygenation (ECMO) can provide complete respiratory support, extracorporeal carbon dioxide removal facilitates protective lung ventilation and provides only partial respiratory support. Mechanical circulatory support with venoarterial (VA) ECMO employed in a traditional central/peripheral fashion or in a temporary ventricular assist device configuration may stabilise patients with decompensated cardiac failure who have evidence of end-organ dysfunction, allowing time for recovery, decision-making, and bridging to implantation of a long-term mechanical circulatory support device and occasionally heart transplantation. In highly selected patients with combined severe cardiac and respiratory failure, advanced ECLS can be provided with central VA ECMO, peripheral VA ECMO with timely transition to venovenous ECMO or VA-venous ECMO upon myocardial recovery to avoid upper body hypoxia or by addition of an oxygenator to the temporary ventricular assist device circuit. This article summarises the available ECLS options and provides insights into the principles and practice of these techniques. One should emphasise that, as is common with many emerging therapies, their optimal use is currently not backed by quality evidence. This deficiency needs to be addressed to ensure that the full potential of ECLS can be achieved.

Routine angiography in survivors of out of hospital cardiac arrest with return of spontaneous circulation: a single site registry.

BACKGROUND: Coronary revascularization in resuscitated out of hospital cardiac arrest (OOHCA) patients has been associated with improved survival. METHODS: This was a retrospective review of patients with OOHCA between 01/07/2007 and 31/03/2009 surviving to hospital admission. Cardiac risk factors, demographics, treatment times, electrocardiogram (ECG), angiographic findings and in-hospital outcomes were recorded. RESULTS: Of the 78 patients, 63 underwent coronary angiography. Traditional cardiac risk factors were common in this group. Chest pain occurred in 33.3% pre-arrest, 59.0% were initially treated at a peripheral hospital, 83.3% had documented ventricular tachycardia or ventricular fibrillation, 55.1% had specific ECG changes, 65.4% had acute myocardial infarction (AMI) as the cause of OOHCA and the majority had multi-vessel disease. ST elevation strongly predicted AMI. The in-hospital survival was 67.9% with neurological deficit in 13.2% of survivors. The group of patients who had an angiogram were more likely to have AMI as a cause of cardiac arrest (71.4% vs 40.0%, p = 0.01) and more likely to have survived to discharge (74.6% vs 40.0%, p < 0.01). Poor outcome was associated with older age, cardiogenic shock, longer transfer times, diabetes, renal impairment and a long duration to return of spontaneous circulation. CONCLUSIONS: Acute myocardial infarction was the commonest cause of OOHCA and a high rate of survival to discharge was seen with a strategy of routine angiography and revascularization.

The combined effects of extracorporeal membrane oxygenation and renal replacement therapy on meropenem pharmacokinetics: a matched cohort study.

INTRODUCTION: The scope of extracorporeal membrane oxygenation (ECMO) is expanding; however, optimal drug prescription during ECMO remains a developing science. Currently, there are no clear guidelines for antibiotic dosing during ECMO. This open-label, descriptive, matched-cohort pharmacokinetics (PK) study aimed to compare the PK of meropenem in ECMO patients to critically ill patients with sepsis not receiving ECMO (controls). METHODS: Eleven adult patients on ECMO (venovenous (VV) ECMO, n = 6; venoarterial (VA) ECMO, n = 5) receiving intravenous (IV) meropenem were included. Meropenem plasma concentrations were determined using validated chromatography. Population PK analysis was performed using non-linear mixed effects modelling. This data was compared with previously published meropenem PK data from 10 critically ill adult patients not on ECMO (preserved renal function (n = 5) or receiving renal replacement therapy (RRT) (n = 5). Using these data, we then performed Monte Carlo simulations (n = 1,000) to describe the effect of creatinine clearance on meropenem plasma concentrations. RESULTS: In total, five (two VV, three VA) out of eleven ECMO patients received RRT. The other six patients (four VV, two VA) had no significant impairment in renal function. A two-compartment model adequately described the data. ECMO patients had numerically higher volume of distribution (0.45 ± 0.17 versus 0.41 ± 0.13 L/kg, P = 0.21) and lower clearance compared to controls (7.9 ± 5.9 versus 11.7 ± 6.5 L/h, P = 0.18). Variability in meropenem clearance was correlated with creatinine clearance or the presence of RRT. The observed median trough concentrations in the controls were 4.2 (0.0 to 5.7) mg/L. In ECMO patients, while trough meropenem concentrations >2 mg/L were achieved in all patients, a more aggressive target of >8 mg/L for less susceptible microorganisms was observed in only eight out of eleven patients, with five of them being on RRT. CONCLUSIONS: ECMO patients exhibit high PK variability. Decreased meropenem CL on ECMO appears to compensate for ECMO and critical illness-related increases in volume of distribution. Routine target concentrations >2 mg/L are maintained with standard dosing (1 g IV 8-hourly). However, an increase in dose may be necessary when targeting higher concentrations or in patients with elevated creatinine clearance.

To ventilate, oscillate, or cannulate?

Ventilatory management of acute respiratory distress syndrome has evolved significantly in the last few decades. The aims have shifted from optimal gas transfer without concern for iatrogenic risks to adequate gas transfer while minimizing lung injury. This change in focus, along with improved ventilator and multiorgan system management, has resulted in a significant improvement in patient outcomes. Despite this, a number of patients develop hypoxemic respiratory failure refractory to lung-protective ventilation (LPV). The intensivist then faces the dilemma of either persisting with LPV using adjuncts (neuromuscular blocking agents, prone positioning, recruitment maneuvers, inhaled nitric oxide, inhaled prostacyclin, steroids, and surfactant) or making a transition to rescue therapies such as high-frequency oscillatory ventilation (HFOV) and/or extracorporeal membrane oxygenation (ECMO) when both these modalities are at their disposal. The lack of quality evidence and potential harm reported in recent studies question the use of HFOV as a routine rescue option. Based on current literature, the role for venovenous (VV) ECMO is probably sequential as a salvage therapy to ensure ultraprotective ventilation in selected young patients with potentially reversible respiratory failure who fail LPV despite neuromuscular paralysis and prone ventilation. Given the risk profile and the economic impact, future research should identify the patients who benefit most from VV ECMO. These choices may be further influenced by the emerging novel extracorporeal carbon dioxide removal devices that can compliment LPV. Given the heterogeneity of acute respiratory distress syndrome, each of these modalities may play a role in an individual patient. Future studies comparing LPV, HFOV, and VV ECMO should not only focus on defining the patients who benefit most from each of these therapies but also consider long-term functional outcomes.

Effect of preoperative renal function on long-term survival after cardiac surgery.

OBJECTIVES: The study objective was to investigate the effect of renal failure on intermediate-term survival in cardiac surgery patients. METHODS: All patients aged 18 years or older undergoing coronary artery bypass grafting, valvular surgery, thoracic aortic surgery, or a combination of these from January 1, 2002 to December 1, 2005 were included. Data were obtained from the cardiac surgery and intensive care databases. Using a matching algorithm, the date of death was obtained from the National Death Index. The simplified Medical Diet for Renal Disease formula was used to calculate the estimated glomerular filtration rate, and the patients were stratified accordingly. An estimation of the effect of the preoperative renal function on the interval to death was determined using Cox regression analysis with and without cubic splines and polynomial regression. The long-term survival was described using the Kaplan-Meier product limit method. RESULTS: A total of 5297 patients were included in the present study. The vital status of all patients was obtained at a mean of 2.9 years (range, 1-5) postoperatively. The actuarial 1-year survival rate was 96% ± 1%, and the 3-year survival rate was 92% ± 1%. The greatest early mortality occurred in the severe renal dysfunction group; however, the dialysis-dependent renal failure group showed increased mortality over time compared with the other groups. The lowest risk of death (longest interval to death) occurred with an estimated glomerular filtration rate of approximately 90 mL/min/1.73 m(2). CONCLUSIONS: The results of our study have shown that preoperative renal dysfunction is an independent predictor of long-term mortality in cardiac surgery patients.

ASAP ECMO: Antibiotic, Sedative and Analgesic Pharmacokinetics during Extracorporeal Membrane Oxygenation: a multi-centre study to optimise drug therapy during ECMO.

BACKGROUND: Given the expanding scope of extracorporeal membrane oxygenation (ECMO) and its variable impact on drug pharmacokinetics as observed in neonatal studies, it is imperative that the effects of the device on the drugs commonly prescribed in the intensive care unit (ICU) are further investigated. Currently, there are no data to confirm the appropriateness of standard drug dosing in adult patients on ECMO. Ineffective drug regimens in these critically ill patients can seriously worsen patient outcomes. This study was designed to describe the pharmacokinetics of the commonly used antibiotic, analgesic and sedative drugs in adult patients receiving ECMO. METHODS/DESIGN: This is a multi-centre, open-label, descriptive pharmacokinetic (PK) study. Eligible patients will be adults treated with ECMO for severe cardiac and/or respiratory failure at five Intensive Care Units in Australia and New Zealand. Patients will receive the study drugs as part of their routine management. Blood samples will be taken from indwelling catheters to investigate plasma concentrations of several antibiotics (ceftriaxone, meropenem, vancomycin, ciprofloxacin, gentamicin, piperacillin-tazobactum, ticarcillin-clavulunate, linezolid, fluconazole, voriconazole, caspofungin, oseltamivir), sedatives and analgesics (midazolam, morphine, fentanyl, propofol, dexmedetomidine, thiopentone). The PK of each drug will be characterised to determine the variability of PK in these patients and to develop dosing guidelines for prescription during ECMO. DISCUSSION: The evidence-based dosing algorithms generated from this analysis can be evaluated in later clinical studies. This knowledge is vitally important for optimising pharmacotherapy in these most severely ill patients to maximise the opportunity for therapeutic success and minimise the risk of therapeutic failure. TRIAL REGISTRATION: ACTRN12612000559819.

Sequestration of drugs in the circuit may lead to therapeutic failure during extracorporeal membrane oxygenation.

INTRODUCTION: Extracorporeal membrane oxygenation (ECMO) is a supportive therapy, with its success dependent on effective drug therapy that reverses the pathology and/or normalizes physiology. However, the circuit that sustains life can also sequester life-saving drugs, thereby compromising the role of ECMO as a temporary support device. This ex vivo study was designed to determine the degree of sequestration of commonly used antibiotics, sedatives and analgesics in ECMO circuits. METHODS: Four identical ECMO circuits were set up as per the standard protocol for adult patients on ECMO. The circuits were primed with crystalloid and albumin, followed by fresh human whole blood, and were maintained at a physiological pH and temperature for 24 hours. After baseline sampling, fentanyl, morphine, midazolam, meropenem and vancomycin were injected into the circuit at therapeutic concentrations. Equivalent doses of these drugs were also injected into four polyvinylchloride jars containing fresh human whole blood for drug stability testing. Serial blood samples were collected from the ECMO circuits and the controls over 24 hours and the concentrations of the study drugs were quantified using validated assays. RESULTS: Four hundred samples were analyzed. All study drugs, except meropenem, were chemically stable. The average drug recoveries from the ECMO circuits and the controls at 24 hours relative to baseline, respectively, were fentanyl 3% and 82%, morphine 103% and 97%, midazolam 13% and 100%, meropenem 20% and 42%, vancomycin 90% and 99%. There was a significant loss of fentanyl (p = 0.0005), midazolam (p = 0.01) and meropenem (p = 0.006) in the ECMO circuit at 24 hours. There was no significant circuit loss of vancomycin at 24 hours (p = 0.26). CONCLUSIONS: Sequestration of drugs in the circuit has implications on both the choice and dosing of some drugs prescribed during ECMO. Sequestration of lipophilic drugs such as fentanyl and midazolam appears significant and may in part explain the increased dosing requirements of these drugs during ECMO. Meropenem sequestration is also problematic and these data support a more frequent administration during ECMO.

Development of simulated and ovine models of extracorporeal life support to improve understanding of circuit-host interactions.

BACKGROUND: Extracorporeal life support (ECLS) is a lifesaving technology that is being increasingly used in patients with severe cardiorespiratory failure. However, ECLS is not without risks. The biosynthetic interface between the patient and the circuit can significantly alter inflammation, coagulation, pharmacokinetics and disposition of trace elements. The relative contributions of the pump, disease and patient in propagating these alterations are difficult to quantify in critically ill patients with multiple organ failure. OBJECTIVE: To design a model where the relevance of individual components could be assessed, in isolation and in combination. DESIGN AND SUBJECTS: Four ECLS models were developed and tested - an in-vitro simulated ECLS circuit; and ECLS in healthy sheep, sheep with acute lung injury (ALI), and sheep with ALI together with transfusion of old or new blood. MAIN OUTCOME MEASURES: Successful design of in-vitro and in-vivo models. RESULTS: We successfully conducted multiple experiments in the simulated circuits and ECLS runs in healthy and ALI sheep. We obtained preliminary data on inflammation, coagulation, histology, pharmacokinetics and trace element disposition during ECLS. CONCLUSIONS: The establishment of in-vitro and in-vivo models provides a powerful means for enhancing knowledge of the pathophysiology associated with ECLS and identification of key factors likely to influence patient outcomes. A clearer description of the contribution of disease and therapeutic interventions may allow improved design of equipment, membranes, medicines and physiological goals for improved patient care.

Outcomes of the first 30 cases of an adult extracorporeal membrane oxygenation program: strategies to manage the "learning curve" and implications for intensive care unit risk adjustment models.

BACKGROUND: We established an adult extracorporeal membrane oxygenation (ECMO) service for cardiorespiratory support in April 2009. Complex therapies may show a learning curve and volume-outcome relationship. OBJECTIVES: To describe our model of care, casemix and outcomes for the first 30 cases together with unique features of this service and potential strategies to manage the learning curve. METHODS: Data were obtained from the intensive care unit database, medical record and minutes of multidisciplinary ECMO review meetings. RESULTS: The model of care was based heavily on that used at an experienced ECMO centre following Extracorporeal Life Support Organization guidelines. ECMO was established as an ICU-managed, multidisciplinary service with collaboration from other specialties using standardised policies and procedures, staff training and formal case review. A specific budget was allocated to training and education and a clinical perfusionist was present on site for the first 10 cases. Seventeen patients received venoarterial (VA) and 13 received venovenous (VV) ECMO. Median duration of ECMO was 7 days for VA and 15 days for VV ECMO. Median ICU stay was 22 days. Twenty patients were referred from 13 hospitals throughout Queensland. Hospital mortality was 47% for VA ECMO and 15% for VV ECMO. The unique features of this service are the use of a Levitronix CentriMag system as well as the Rotaflow system, and the use of extended daily haemodiafiltration using the Fresenius 4008s ARrT plus connected into the ECMO circuit. The clinical implications of conducting plasma exchange and sustained low-efficiency dialysis via direct ECMO circuit connection using the Fresenius ARrT machine, and using a second system for ECMO support, were notable challenges. CONCLUSION: Satisfactory outcomes were achieved using an ICU-based multidisciplinary approach with a broadly based education strategy with additional clinical perfusionist support to manage the learning curve.

Impact of blood product transfusion on short and long-term survival after cardiac surgery: more evidence.

BACKGROUND: Despite the proven benefits in hemorrhagic shock, blood transfusions have been linked to increased morbidity and mortality. The short-term adverse effects of blood transfusion in cardiac surgical patients are well documented but there are very few studies that adequately assess the long-term survival. This study was undertaken to evaluate the effects of transfusion on both short-term and long-term survival after cardiac surgery. METHODS: Data from 5,342 patients who underwent a cardiac surgical procedure from January 2002 to December 2005 at our institution were reviewed. The effect of transfusion of packed red blood cells (PRBC) and other blood products was tested in a 2-level approach of transfusion (any) versus no transfusion, and also a 4-level approach of transfusion (PRBC, other blood products, and both blood and blood products) versus no transfusion. Long-term survival data of these patients were obtained. Cox proportional hazard models, Kaplan-Meier survival plots, and hazard functions were used to compare the groups. RESULTS: A total of 3,013 of the 5,342 study patients (56.4%) received transfusion during or within 72 hours of their cardiac surgery. Median time to death was significantly lower for patients who received transfusions; 1.15 years for PRC and 0.83 years for any transfusion, compared with 4.68 years in the non-transfused group. The overall 30-day mortality was 1.7%, but in patients who received transfusions (3.6%) was significantly higher than the non-transfused group (0.3%, p<0.001). The 1-year mortality (overall 3.9%) in the transfused group (7.3%, p<0.001) was also significantly higher than that in the non-transfused group (1.3%). The 5-year mortality rate in the transfused group was more than double that in the non-transfused group (16% vs 7%). After correction for comorbidities and other factors, transfusion was still associated with a 66% increase in mortality. CONCLUSIONS: This study suggests that blood or blood product transfusion during or after cardiac surgery is associated with increased short-term and long-term mortality. It reinforces the need for prospective randomized controlled studies for evaluation of restrictive transfusion triggers and objective clinical indicators for transfusion in the cardiac surgical patient population.

Risk factors and survival in patients with respiratory failure after cardiac operations.

BACKGROUND: Respiratory failure is a known complication of cardiac operations and contributes to postoperative morbidity and death. This study assessed the relevance of risk factors in the development of respiratory failure, defined as postoperative ventilation exceeding 48 hours, and looked at the effect of respiratory failure on short-term and long-term mortality rates. METHODS: De-identified data for patients who underwent cardiac surgical procedures at The Prince Charles Hospital between January 2002 and December 2007 were collected prospectively and analyzed using logistic regression to identify significant risk factors associated with respiratory failure. Long-term mortality data were analyzed for patients who underwent operations between 1994 and 2005 using Kaplan-Meier survival curves. RESULTS: The risk factor analysis included 7,440 patients. Identified risk factors for respiratory failure included critical preoperative state, neurologic dysfunction, poor left ventricular function, active endocarditis, chronic obstructive pulmonary disease, elevated preoperative creatinine, previous cardiac operation, and age. Survival was assessed in 18,488 patients and demonstrated increased short-term and long-term mortality rates when respiratory failure developed and increased mortality rates with increasing duration of respiratory failure. CONCLUSIONS: Respiratory failure is complication of cardiac operations associated with increased mortality and cost. Identification of patients at risk of respiratory failure may help select surgical candidates and aid resource planning and optimization.

An application of outcomes monitoring for coronary artery bypass surgery 2005-2008 at TPCH.

OBJECTIVE: To describe monitoring of four years' isolated coronary artery bypass surgery outcomes and complications at The Prince Charles Hospital, Brisbane, Australia. METHODS: Analysis of Cardiac Surgical Register database using tabulations, funnel plots and random-effects (Bayesian shrinkage) analysis for aggregated data. Combined CUSUM and cumulative observed minus expected (modified VLAD) charts and combined CUSUM and cumulative funnel plots used for individual observation sequential data and binomial control charts and generalised additive models (GAMs) for quarterly sequential data. Risk adjustment employed re-calibrated EuroSCORE. RESULTS: There were 2575 procedures with an unadjusted in-hospital mortality rate of 1.17%. Mean age was 65 years and 21% of patients were female; 43.6% were elective procedures. Median ventilation time was 10 hours and median length of stay in intensive care (ICU) was 23 hours. Return to theatre for bleeding occurred in 3% of cases. Return to theatre for surgical site infection occurred in 0.4% of cases; 4% were re-do procedures. Permanent stroke or neurological deficit occurred in 1%, perioperative myocardial infarction in 0.8%, arrest in 1.2%, renal failure in 1.6% and ICU return in 2.3% of cases. CONCLUSIONS: Complication rates and mortality were comparable with similar units. Use of random-effects (Bayesian shrinkage) analysis for aggregated data is encouraged together with generalised additive models (GAMs) and combined CUSUM and cumulative observed minus expected (modified VLAD) charts for sequential data.

A prospective pilot study evaluating the 'cardiac decompensation score' in the setting of intraaortic balloon counterpulsation.

The study objective was to determine whether the 'cardiac decompensation score' could identify cardiac decompensation in a patient with existing cardiac compromise managed with intraaortic balloon counterpulsation (IABP). A one-group, posttest-only design was utilised to collect observations in 2003 from IABP recipients treated in the intensive care unit of a 450 bed Australian, government funded, public, cardiothoracic, tertiary referral hospital. Twenty-three consecutive IABP recipients were enrolled, four of whom died in ICU (17.4%). All non-survivors exhibited primarily rising scores over the observation period (p<0.001) and had final scores of 25 or higher. In contrast, the maximum score obtained by a survivor at any time was 15. Regardless of survival, scores for the 23 participants were generally decreasing immediately following therapy escalation (p=0.016). Further reflecting these changes in patient support, there was also a trend for scores to move from rising to falling at such treatment escalations (p=0.024). This pilot study indicates the 'cardiac decompensation score' to accurately represent changes in heart function specific to an individual patient. Use of the score in conjunction with IABP may lead to earlier identification of changes occurring in a patient's cardiac function and thus facilitate improved IABP outcomes.

Influence of timing of intraaortic balloon placement in cardiac surgical patients.

OBJECTIVE: The study objective was to evaluate the association between timing of intraaortic balloon pump insertion and outcomes in patients undergoing cardiac surgery. METHODS: All patients aged 18 years or more who underwent coronary artery bypass surgery, cardiac valve surgery, or thoracic aortic surgery between January 2002 and December 2007 were included. Data were obtained from cardiac surgery and intensive care databases. Patients were categorized as receiving a preoperative, intraoperative, or postoperative intraaortic balloon pump and compared with a reference group who did not receive an intraaortic balloon pump. Summary and descriptive statistics were used to compare the groups. Logistic regression was used to model in-hospital mortality, and survival methods were used to model time to event data, such as length of stay. RESULTS: There were 7440 patients included over a 6-year period, of whom 217 (2.9%) received a preoperative intraaortic balloon pump, 184 (2.4%) received an intraoperative intraaortic balloon pump, and 42 (0.56%) received a postoperative intraaortic balloon pump. Logistic European System for Cardiac Operative Risk Evaluation-derived predicted risk of death was higher across all intraaortic balloon pump groups compared with the group with no intraaortic balloon pump. Observed in-hospital mortality was significantly lower in the preoperative group (10%) and the group with no intraaortic balloon pump (0.8%) compared with the intraoperative (16%) and postoperative (29%) groups. Risk-adjusted mortality was also lower in the preoperative group. CONCLUSION: This study comparing outcomes in patients undergoing cardiac surgical procedures with timing of intraaortic balloon pump placement revealed that the use of preoperative intraaortic balloon pumps was associated with a strong trend toward reduction in in-hospital mortality despite a higher predicted mortality in this group. The study provides support to the growing body of literature advocating preoperative use of intraaortic balloon pumps in carefully selected patients.

The association between preoperative eGFR and outcomes in cardiac surgical patients.

AIM: To study the relationship between preoperative renal function and outcomes in patients undergoing cardiac surgery. DESIGN, SETTING AND PARTICIPANTS: A retrospective descriptive study was performed on all patients who had coronary artery bypass, cardiac valve surgery and/or aortic arch surgery at a tertiary-referral hospital between January 2002 and December 2007. MAIN OUTCOME MEASURES: Clinical and demographic variables were compared across renal dysfunction categories, defined by glomerular filtration rate (eGFR) calculated using the modified Modification of Diet in Renal Disease (MDRD) equation. Logistic regression was used to assess the association between eGFR and outcomes, primarily in-hospital mortality. RESULTS: 7440 patients were included, with a mean age of 64 years and overall mortality of 1.6%. Across worsening renal function states, excluding patients receiving dialysis, patients were older, more likely to be women and to have comorbidities (particularly diabetes and vascular disease), as well as ventricular dysfunction, and to require emergency or more complex surgery. Unadjusted outcomes, as well as univariate and multivariate analysis, consistently demonstrated that odds ratios for adverse events increased with worsening renal function, even at moderate levels of dysfunction. CONCLUSIONS: Preoperative renal dysfunction is independently associated with mortality after cardiac surgery. This is consistent with the accumulating evidence supporting preoperative renal dysfunction as a powerful predictor of adverse outcomes.