Population pharmacokinetics of fluconazole in critically ill patients receiving extracorporeal membrane oxygenation and continuous renal replacement therapy: an ASAP ECMO study.

This multicenter study describes the population pharmacokinetics (PK) of fluconazole in critically ill patients receiving concomitant extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT) and includes an evaluation of different fluconazole dosing regimens for achievement of target exposure associated with maximal efficacy. Serial blood samples were obtained from critically ill patients on ECMO and CRRT receiving fluconazole. Total fluconazole concentrations were measured in plasma using a validated chromatographic assay. A population PK model was developed and Monte Carlo dosing simulations were performed using Pmetrics in R. The probability of target attainment (PTA) of various dosing regimens to achieve fluconazole area under the curve to minimal inhibitory concentration ratio (AUC0-24/MIC) >100 was estimated. Eight critically ill patients receiving concomitant ECMO and CRRT were included. A two-compartment model including total body weight as a covariate on clearance adequately described the data. The mean (±standard deviation, SD) clearance and volume of distribution were 2.87 ± 0.63 L/h and 15.90 ± 13.29 L, respectively. Dosing simulations showed that current guidelines (initial loading dose of 12 mg/kg then 6 mg/kg q24h) achieved >90% of PTA for a MIC up to 1 mg/L. None of the tested dosing regimens achieved 90% of PTA for MIC above 2 mg/L. Current fluconazole dosing regimen guidelines achieved >90% PTA only for Candida species with MIC <1 mg/L and thus should be only used for Candida-documented infections in critically ill patients receiving concomitant ECMO and CRRT. Total body weight should be considered for fluconazole dose.

Patient safety and hospital visiting at the end of life during COVID-19 restrictions in Aotearoa New Zealand: a qualitative study.

BACKGROUND: Visiting restrictions were enacted in Aotearoa New Zealand to reduce transmission of COVID-19 and protect the healthcare system. This research aimed to investigate the experiences of families and clinicians of hospital visiting for people with palliative and end-of-life care needs during restrictions. METHODS: Semistructured interviews were completed between March and October 2021 with family members and clinicians who had personally experienced enactment of visiting restrictions during pandemic restrictions. A critical realist ontology was used to approach data analysis, sorting and coding to generate themes. RESULTS: Twenty-seven participants were interviewed, 13 being families who had experienced bereavement of a family member during the restrictions: seven nurses or physicians and seven being non-bereaved family members. Four themes were generated: patient safety-(re)defining the 'Visitor'; the primacy of SARS-CoV-2-patient safety and negotiating risk; dying alone: enduring harms; and agency, strategies and workarounds. CONCLUSION: Visitor rights and visitor policy at the end of life require greater protection during a pandemic. Transparent, coherent, publicly available evidence-based guidelines that key stakeholders, including patients, families and ethicists, are included in producing, are urgently required. We want to avert a legacy of disenfranchised grief in future pandemics.

Antimicrobial Exposures in Critically Ill Patients Receiving Extracorporeal Membrane Oxygenation.

Rationale: Data suggest that altered antimicrobial concentrations are likely during extracorporeal membrane oxygenation (ECMO). Objectives: The primary aim of this analysis was to describe the pharmacokinetics (PKs) of antimicrobials in critically ill adult patients receiving ECMO. Our secondary aim was to determine whether current antimicrobial dosing regimens achieve effective and safe exposure. Methods: This study was a prospective, open-labeled, PK study in six ICUs in Australia, New Zealand, South Korea, and Switzerland. Serial blood samples were collected over a single dosing interval during ECMO for 11 antimicrobials. PK parameters were estimated using noncompartmental methods. Adequacy of antimicrobial dosing regimens were evaluated using predefined concentration exposures associated with maximal clinical outcomes and minimal toxicity risks. Measurements and Main Results: We included 993 blood samples from 85 patients. The mean age was 44.7 ± 14.4 years, and 61.2% were male. Thirty-eight patients (44.7%) were receiving renal replacement therapy during the first PK sampling. Large variations (coefficient of variation of ⩾30%) in antimicrobial concentrations were seen leading to more than fivefold variations in all PK parameters across all study antimicrobials. Overall, 70 (56.5%) concentration profiles achieved the predefined target concentration and exposure range. Target attainment rates were not significantly different between modes of ECMO and renal replacement therapy. Poor target attainment was observed across the most frequently used antimicrobials for ECMO recipients, including for oseltamivir (33.3%), piperacillin (44.4%), and vancomycin (27.3%). Conclusions: Antimicrobial PKs were highly variable in critically ill patients receiving ECMO, leading to poor target attainment rates. Clinical trial registered with the Australian New Zealand Clinical Trials Registry (ACTRN12612000559819).

Population Pharmacokinetics and Dosing Simulations of Ceftriaxone in Critically Ill Patients Receiving Extracorporeal Membrane Oxygenation (An ASAP ECMO Study).

BACKGROUND: Despite the surge in use of extracorporeal membrane oxygenation (ECMO) in the adult intensive care unit, little guidance is available on the appropriate dosing of antimicrobials in this setting. Ceftriaxone is an antimicrobial with a high affinity to plasma protein, a property identified in the literature as susceptible to sequestration into extracorporeal circuits and hypothesised to require dosage adjustments in this setting. OBJECTIVE: The aim of this study was to describe the pharmacokinetics of ceftriaxone and identify the best dosing regimen for critically ill adult patients receiving ECMO. METHODS: Serial blood samples were taken from patients receiving both ECMO and ceftriaxone. Total and unbound drug concentrations were measured in plasma by chromatographic assay and analysed using a population pharmacokinetic approach with Pmetrics®. Dosing simulations were performed to identify the optimal dosing strategy: 60 and 100% of time with free (unbound) drug concentration exceeding the minimum inhibitory concentration (fT>MIC). RESULTS: In total, 14 patients were enrolled, of which three were receiving renal replacement therapy (RRT). Total and unbound ceftriaxone was best described in a two-compartment model with total body weight, serum albumin concentrations, creatinine clearance (CrCL), and the presence of RRT included as significant predictors of pharmacokinetics. Patients not on RRT generated a mean renal clearance of 0.90 L/h, non-renal clearance of 0.33 L/h, and central volume of distribution of 7.94 L. Patients on RRT exhibited a mean total clearance of 1.18 L/h. ECMO variables were not significant predictors of ceftriaxone pharmacokinetics. Steady-state dosing simulations found that dosages of 1 g every 12 h and 2 g every 24 h achieved >90% probabilities of target attainment in patients with CrCL of 0 mL/min with RRT and 30 and 100 mL/min and various serum albumin concentrations (17 and 26 g/L). CONCLUSIONS: Dosing recommendations for critically ill adult patients not on ECMO appear to be sufficient for patients on ECMO. Patients exhibiting augmented renal clearance (> 130 mL/min) or treatment of less susceptible pathogens may require higher doses, which requires further investigation.

Population Pharmacokinetics of Vancomycin in Critically Ill Adult Patients Receiving Extracorporeal Membrane Oxygenation (an ASAP ECMO Study).

Our study aimed to describe the population pharmacokinetics (PK) of vancomycin in critically ill patients receiving extracorporeal membrane oxygenation (ECMO), including those receiving concomitant renal replacement therapy (RRT). Dosing simulations were used to recommend maximally effective and safe dosing regimens. Serial vancomycin plasma concentrations were measured and analyzed using a population PK approach on Pmetrics. The final model was used to identify dosing regimens that achieved target exposures of area under the curve (AUC0-24) of 400-700 mg · h/liter at steady state. Twenty-two patients were enrolled, of which 11 patients received concomitant RRT. In the non-RRT patients, the median creatinine clearance (CrCL) was 75 ml/min and the mean daily dose of vancomycin was 25.5 mg/kg. Vancomycin was well described in a two-compartment model with CrCL, the presence of RRT, and total body weight found as significant predictors of clearance and central volume of distribution (Vc). The mean vancomycin renal clearance and Vc were 3.20 liters/h and 29.7 liters respectively, while the clearance for patients on RRT was 0.15 liters/h. ECMO variables did not improve the final covariate model. We found that recommended dosing regimens for critically ill adult patients not on ECMO can be safely and effectively used in those on ECMO. Loading doses of at least 25 mg/kg followed by maintenance doses of 12.5-20 mg/kg every 12 h are associated with a 97-98% probability of efficacy and 11-12% probability of toxicity, in patients with normal renal function. Therapeutic drug monitoring along with reductions in dosing are warranted for patients with renal impairment and those with concomitant RRT. (This study is registered with the Australian New Zealand Clinical Trials Registry [ANZCTR] under number ACTRN12612000559819.).

Patient's experiences of endotracheal tubes and suction following cardiac surgery.

BACKGROUND: There is a growing body of evidence addressing the patient experience of intensive care, including patient reports that the presence of an endotracheal tube is bothersome and distressing, and that endotracheal suction is moderately to extremely painful. Yet there remains little information about the patient experience of the endotracheal tube and suction in those patients receiving planned short-term mechanical ventilation. AIMS AND OBJECTIVES: This study aimed to describe the patient experience of the endotracheal tube and suction, following mechanical ventilation in post-operative cardiac surgical patients. DESIGN: This qualitative study used inductive thematic analysis. Participants having planned cardiac surgery, anticipated to receive less than 12-hours mechanical ventilation, were approached pre-operatively and written consent provided. METHODS: Ten participants were recruited using purposive sampling. Semi-structured interviews were conducted between days four and six post-operatively. One researcher interviewed all participants; two researchers independently read, coded, and agreed themes. FINDINGS: None of the participants recalled endotracheal suction, while half had no recollection of the endotracheal tube. Three themes were identified; the experience of the endotracheal tube and extubation, the experience of emerging from sedation, and participants concerns about the future. The presence of the endotracheal tube was described as bothersome, whilst breathing through the tube and extubation were described as 'weird' and 'strange' but not painful. CONCLUSIONS: Knowledge of the patient experience can help inform nursing practice by improving pre and post-operative care planning. RELEVANCE TO CLINICAL PRACTICE: This study adds to the body of knowledge about the patient experience of the endotracheal tube and extubation. TRIAL REGISTRATION: Prospective registration with the Australian New Zealand Clinical Trials Registry. www.anzctr.org.au (ACTRN12616001515482).

A pilot randomized clinical trial of cryopreserved versus liquid-stored platelet transfusion for bleeding in cardiac surgery: The cryopreserved versus liquid platelet-New Zealand pilot trial.

BACKGROUND AND OBJECTIVES: Platelets for transfusion have a shelf-life of 7 days, limiting availability and leading to wastage. Cryopreservation at -80°C extends shelf-life to at least 1 year, but safety and effectiveness are uncertain. MATERIALS AND METHODS: This single centre blinded pilot trial enrolled adult cardiac surgery patients who were at high risk of platelet transfusion. If treating clinicians determined platelet transfusion was required, up to three units of either cryopreserved or liquid-stored platelets intraoperatively or during intensive care unit admission were administered. The primary outcome was protocol safety and feasibility. RESULTS: Over 13 months, 89 patients were randomized, 23 (25.8%) of whom received a platelet transfusion. There were no differences in median blood loss up to 48 h between study groups, or in the quantities of study platelets or other blood components transfused. The median platelet concentration on the day after surgery was lower in the cryopreserved platelet group (122 × 103 /µl vs. 157 × 103 /µl, median difference 39.5 ×103 /µl, p = 0.03). There were no differences in any of the recorded safety outcomes, and no adverse events were reported on any patient. Multivariable adjustment for imbalances in baseline patient characteristics did not find study group to be a predictor of 24-h blood loss, red cell transfusion or a composite bleeding outcome. CONCLUSION: This pilot randomized controlled trial demonstrated the feasibility of the protocol and adds to accumulating data supporting the safety of this intervention. Given the clear advantage of prolonged shelf-life, particularly for regional hospitals in New Zealand, a definitive non-inferiority phase III trial is warranted.

Population Pharmacokinetics of Piperacillin and Tazobactam in Critically Ill Patients Receiving Extracorporeal Membrane Oxygenation: an ASAP ECMO Study.

Our study aimed to describe the population pharmacokinetics (PK) of piperacillin and tazobactam in patients on extracorporeal membrane oxygenation (ECMO), with and without renal replacement therapy (RRT). We also aimed to use dosing simulations to identify the optimal dosing strategy for these patient groups. Serial piperacillin and tazobactam plasma concentrations were measured with data analyzed using a population PK approach that included staged testing of patient and treatment covariates. Dosing simulations were conducted to identify the optimal dosing strategy that achieved piperacillin target exposures of 50% and 100% fraction of time free drug concentration is above MIC (%fT>MIC) and toxic exposures of greater than 360 mg/liter. The tazobactam target of percentage of time free concentrations of >2 mg/liter was also assessed. Twenty-seven patients were enrolled, of which 14 patients were receiving concurrent RRT. Piperacillin and tazobactam were both adequately described by two-compartment models, with body mass index, creatinine clearance, and RRT as significant predictors of PK. There were no substantial differences between observed PK parameters and published parameters from non-ECMO patients. Based on dosing simulations, a 4.5-g every 6 hours regimen administered over 4 hours achieves high probabilities of efficacy at a piperacillin MIC of 16 mg/liter while exposing patients to a <3% probability of toxic concentrations. In patients receiving ECMO and RRT, a frequency reduction to every 12 hours dosing lowers the probability of toxic concentrations, although this remains at 7 to 9%. In ECMO patients, piperacillin and tazobactam should be dosed in line with standard recommendations for the critically ill.

A Multicenter, Open-Label, Randomized Controlled Trial of a Conservative Fluid Management Strategy Compared With Usual Care in Participants After Cardiac Surgery: The Fluids After Bypass Study.

OBJECTIVES: There is little evidence to guide fluid administration to patients admitted to the ICU following cardiac surgery. This study aimed to determine if a protocolized strategy known to reduce fluid administration when compared with usual care reduced ICU length of stay following cardiac surgery. DESIGN: Prospective, multicenter, parallel-group, randomized clinical trial. SETTING: Five cardiac surgical centers in New Zealand conducted from November 2016 to December 2018 with final follow-up completed in July 2019. PATIENTS: Seven-hundred fifteen patients undergoing cardiac surgery; 358 intervention and 357 usual care. INTERVENTIONS: Randomization to protocol-guided strategy utilizing stroke volume variation to guide administration of bolus fluid or usual care fluid administration until desedation or up to 24 hours. Primary outcome was length of stay in ICU. Organ dysfunction, mortality, process of care measures, patient-reported quality of life, and disability-free survival were collected up to day 180. MEASUREMENTS AND MAIN RESULTS: Overall 666 of 715 (93.1%) received at least one fluid bolus. Patients in the intervention group received less bolus fluid (median [interquartile range], 1,000 mL [250-2,000 mL] vs 1,500 mL [500-2,500 mL]; p < 0.0001) and had a lower overall fluid balance (median [interquartile range], 319 mL [-284 to 1,274 mL] vs 673 mL [38-1,641 mL]; p < 0.0001) in the intervention period. There was no difference in ICU length of stay between the two groups (27.9 hr [21.8-53.5 hr] vs 25.6 hr [21.9-64.6 hr]; p = 0.95). There were no differences seen in development of organ dysfunction, quality of life, or disability-free survival at any time points. Hospital mortality was higher in the intervention group (4% vs 1.4%; p = 0.04). CONCLUSIONS: A protocol-guided strategy utilizing stroke volume variation to guide administration of bolus fluid when compared with usual care until desedation or up to 24 hours reduced the amount of fluid administered but did not reduce the length of stay in ICU.

Avoidance of Routine Endotracheal Suction in Subjects Ventilated for ≤ 12 Hours Following Elective Cardiac Surgery.

BACKGROUND: Mechanical ventilation requires an endotracheal tube. Airway management includes endotracheal suctioning, a frequent procedure for patients in the ICU. Associated risks of endotracheal suctioning include hypoxia, atelectasis, and infection. There is currently no evidence about the safety of avoiding endotracheal suction. We aimed to assess the safety of avoiding endotracheal suction, including at extubation, in cardiac surgical patients who were mechanically ventilated for ≤ 12 h. METHODS: We conducted a single-center, noninferiority, randomized controlled trial in a cardiac ICU in a metropolitan tertiary teaching hospital. Subjects were assigned to either avoidance of endotracheal suction or to usual care including endotracheal suctioning during mechanical ventilation. In total, we screened 468 patients and randomized 249 subjects (usual care, n = 125; intervention, n = 124). Subjects were elective cardiac surgical patients anticipated to receive ≤ 12 h of mechanical ventilation. The primary outcome was the [Formula: see text]/[Formula: see text] on room air 6 h after extubation, with a noninferiority margin of 10% (lower bound of one-sided 95% CI to be < 30). RESULTS: There were no differences in group characteristics at baseline. The primary analysis was a per-protocol analysis performed on 154 subjects. The median [Formula: see text]/[Formula: see text] was 323 for the intervention group and 311 for the standard care group (median difference = 12, one-sided 95% CI -14.3). The results were consistent when using an intention-to-treat analysis and a 97.5% CI. There were no differences between groups in complications or safety measures, including the escalation of oxygen therapy. CONCLUSIONS: Endotracheal suctioning can be safely minimized or avoided in low-risk patients who have had cardiac surgery and are expected to be ventilated for < 12 h after surgery.

Study protocol: A randomized controlled trial assessing the avoidance of endotracheal suction in cardiac surgical patients ventilated for ≤ 12 hr.

AIMS: To assess the safety and efficacy of avoiding endotracheal suction in postoperative cardiac surgical patients mechanically ventilated for ≤ 12 hr. DESIGN: A prospective, single centre, single blind, non-inferiority, randomized controlled trial evaluating the safety and efficacy of avoiding suction in uncomplicated, postoperative, adult cardiac surgical patients mechanically ventilated for ≤ 12 hr. METHODS: Randomization will be performed on return to intensive care (ICU) with allocation to either usual postoperative care including suction or to usual care with no suction (intervention arm). The primary outcome is the ratio of partial pressure of oxygen (PaO2 ) to fraction of inspired oxygen (FiO2 ) (P/F) 6 hr after extubation. Pain assessments will be performed before, during and after endotracheal suction (ETS) and the patient experience will be investigated with a brief interview the following day. Ethics approval was received in October 2015. DISCUSSION: Endotracheal suction is performed as part of airway management but has potential complications and there is little robust evidence to guide practice. This study will add to the evidence base about the need and benefit of endotracheal suction in this patient cohort. IMPACT: As there is currently no published evidence about the safety of avoiding endotracheal suction. This study will provide the first evidence about avoidance of endotracheal suction in patients ventilated for less than 1 day. If non-inferior, the results have the capacity to change nursing practice by avoiding a potentially unnecessary procedure, it will build on the body of knowledge about the patient experience.

Endotracheal suction in intensive care: A point prevalence study of current practice in New Zealand and Australia.

BACKGROUND: Despite the evidence and available guidelines about endotracheal suction (ETS), a discrepancy between published guidelines and clinical practice persists. To date, ETS practice in the adult intensive care unit (ICU) population across New Zealand and Australia has not been described. OBJECTIVE: To describe ICU nurses' ETS practice in New Zealand and Australia including the triggers for performing endotracheal suction. METHODS: A single day, prospective observational, binational, multicentre point prevalence study in New Zealand and Australian ICUs. All adult patients admitted at 10:00 on the study day were included. MAIN OUTCOME MEASURES: In addition to patient demographic data, we assessed triggers for ETS, suction canister pressures, use of preoxygenation, measures of oxygenation, and ETS at extubation. RESULTS: There were 682 patients in the ICUs on the study day, and 230 were included in the study. Three of 230 patients were excluded for missing data. A total of 1891 ETS events were performed on 227 patients during the study day, a mean of eight interventions per patient. The main triggers reported were audible (n = 385, 63%) and visible (n = 239, 39%) secretions. Less frequent triggers included following auscultation (n = 142, 23%), reduced oxygen saturations (n = 140, 22%), and ventilator waveforms (n = 53, 9%). Mean suction canister pressure was -337 mmHg (standard deviation = 189), 67% of patients received preoxygenation (n = 413), and ETS at extubation was performed by 84% of nurses. CONCLUSION: Some practices were inconsistent with international guidelines, in particular concerning patient assessment for ETS and suction canister pressure.

Design and statistical analysis plan for a trial comparing a conservative fluid management strategy with usual care in patients after cardiac surgery: the FAB study.

BACKGROUND: Cardiac surgery is one of the most frequently performed major surgical procedures. Following surgery, haemodynamic instability and prevention of organ dysfunction may be treated in the intensive care unit (ICU) with intravenous fluid, inotropes and vasopressors. In other surgical groups, liberal intravenous fluid administration and a positive fluid balance have been associated with adverse outcomes and increased risk of morbidity and mortality. There is a paucity of evidence to guide intravenous fluid administration in cardiac surgery patients. We have previously shown that a protocol-guided strategy avoiding unnecessary fluid administration significantly reduces fluid loading. OBJECTIVE: To present the design and statistical analysis plan for a randomised controlled trial comparing a conservative fluid management strategy to usual care in patients after cardiac surgery. METHODS: We designed a prospective, multicentre, parallel-group, randomised controlled trial - the FAB (Fluids After Bypass) study. A total of 700 patients undergoing cardiac surgery using cardiopulmonary bypass who have a European System for Cardiac Operative Risk Evaluation (EuroSCORE) II ≥ 0.9 will be enrolled in this study and randomly allocated to a protocol-guided strategy using stroke volume variation to guide administration of bolus fluid or to usual care fluid administration in a 1:1 ratio, stratified by centre. Study treatment will be administered from post-operative admission to the ICU until de-sedation or for a 24-hour period (whichever is shorter). The primary outcome is ICU length of stay. Secondary endpoints include quality of life and disability-free survival at 3 and 6 months after surgery, and process-of-care, physiological and safety measures. CONCLUSION: This trial aims to determine whether a protocol-guided strategy that avoids unnecessary fluid administration reduces ICU length of stay and improves outcomes in higher-risk adults undergoing cardiac surgery.

Fluid resuscitation associated with elevated angiopoietin-2 and length of mechanical ventilation after cardiac surgery.

BACKGROUND: Fluid restriction in patients with acute respiratory distress syndrome increases ventilator-free days while lowering plasma angiopoietin-2 (Ang-2), a marker of pulmonary endothelial injury. We hypothesised that fluid resuscitation may lead to endothelial injury after cardiac surgery and analysed Ang-2, angiopoietin-1 (Ang-1) and phospholipase A2 (PLA2) levels and the impact of fluid management on ventilation time. METHODS: Patients enrolled in a single-centre, prospectively randomised interventional study of liberal or conservative fluid resuscitation strategy had plasma Ang-2, Ang-1 and PLA2 levels measured at baseline (pre-operative), 6 and 24 hours after commencement of cardiopulmonary bypass, and analysed by linear mixed models as liberal v conservative (intention to treat) or high v low fluid group (actual treatment, ≥ 3250 mL of fluid administered), and further subclassified as EuroSCORE (European System for Cardiac Operative Risk Evaluation) II ≥ 0.9 or < 0.9. RESULTS: Over 9 months, 144 patients were randomly allocated to either liberal (n =74) or conservative (n =70) fluid. Patients in the liberal fluid arm tended to an increased Ang-2 (P =0.12) and had higher PLA2 levels (P =0.03). Based on actual fluid administered, Ang-2 levels were higher, the Ang-1/Ang-2 ratio lower, and the length of mechanical ventilation and intensive care unit (ICU) stay was longer in the high fluid group (P < 0.001). The highest levels of Ang- 2 and corresponding lowest Ang-1/Ang-2 ratio, along with longest length of mechanical ventilation and ICU stay, were found with both the liberal and high fluid groups in patients with a EuroSCORE II ≥ 0.9 (P < 0.01). CONCLUSION: Liberal fluid resuscitation after cardiac surgery was associated with both pulmonary endothelial injury and prolonged length of mechanical ventilation. CLINICAL TRIAL REGISTRATION: ACTRN12612000754842.

Nonocclusive mesenteric infarction after cardiac surgery: potential biomarkers.

BACKGROUND: Nonocclusive mesenteric ischemia can cause intestinal infarction but the diagnosis is challenging. This prospective study evaluated three plasma biomarkers of intestinal infarction after cardiac surgery. MATERIALS AND METHODS: Patients were recruited after cardiac surgery if they required laparotomy (with or without intestinal resection) for suspected nonocclusive mesenteric ischemia. Plasma levels of D-lactate, intestinal fatty acid-binding protein (i-FABP), and smooth muscle actin (SMA) before laparotomy were measured. RESULTS: Twenty patients were recruited (68 ± 9 y, EuroSCORE: 8.7 ± 2.8, mortality 70%). A positive laparotomy (n = 13) was associated with no change in D-lactate (P = 0.95), decreased i-FABP (P = 0.007), and increased SMA (P = 0.01). All patients with high SMA had a positive laparotomy. A subgroup analysis was undertaken in the eight patients who required multiple laparotomies. D-lactate increased between the two laparotomies in nonsurvivors (n = 4). Plasma i-FABP (P = 0.008) and SMA (P = 0.036) significantly decreased after the bowel resection, regardless of survival outcome. CONCLUSIONS: None of the biomarkers were accurate enough to reliably diagnose intestinal infarction. However, all patients with high values of SMA developed intestinal infarction, thus warranting further investigation. An increasing D-lactate after intestinal resection suggests impending death.

A Multicenter, Randomized, Controlled Phase IIb Trial of Avoidance of Hyperoxemia during Cardiopulmonary Bypass.

BACKGROUND: Cardiac surgery utilizing cardiopulmonary bypass (CPB) is one of the most common forms of major surgery. Cardiac surgery-associated multiorgan dysfunction (CSA-MOD) is well recognized and includes acute kidney injury (AKI), hepatic impairment, myocardial damage, and postoperative neurologic deficit. Pathophysiology of CSA-MOD involves numerous injurious pathways linked to the use of CPB including oxidative stress and formation of reactive iron species. During cardiac surgery with CPB, arterial return blood is oxygenated to supranormal levels. This study aimed to determine whether the avoidance of arterial hyperoxemia decreased oxidative stress and reduced the severity of the multiorgan dysfunction in patients undergoing cardiac surgery utilizing CPB. METHODS: The study was a multicenter, open-label, parallel-group, randomized controlled study of the avoidance of arterial hyperoxemia versus usual care in patients undergoing cardiac surgery involving CPB. Primary outcome was the incidence and severity of AKI. Secondary outcomes included serum biomarkers for CSA-MOD, duration of mechanical ventilation, and length of intensive care and hospital stay. RESULTS: A total of 298 patients were randomized and analyzed at two hospitals in New Zealand and Australia. Mean PaO2 was significantly different between groups during CPB. There was no difference in the development of AKI (intervention arm 72.0% vs. usual care 66.2%; difference, -5.8% [95% CI, -16.1 to 4.7%]; P = 0.28), other markers of organ damage, or intensive care unit and hospital length of stay. CONCLUSIONS: Avoiding modest hyperoxemia during CPB failed to demonstrate any difference in AKI, markers of organ damage, or length of stay.

Targeted therapeutic mild hypercapnia after cardiac arrest: A phase II multi-centre randomised controlled trial (the CCC trial).

BACKGROUND: In intensive care observational studies, hypercapnia after cardiac arrest (CA) is independently associated with improved neurological outcome. However, the safety and feasibility of delivering targeted therapeutic mild hypercapnia (TTMH) for such patients is untested. METHODS: In a phase II safety and feasibility multi-centre, randomised controlled trial, we allocated ICU patients after CA to 24h of targeted normocapnia (TN) (PaCO2 35-45mmHg) or TTMH (PaCO2 50-55mmHg). The primary outcome was serum neuron specific enolase (NSE) and S100b protein concentrations over the first 72h assessed in the first 50 patients surviving to day three. Secondary end-points included global measure of function assessment at six months and mortality for all patients. RESULTS: We enrolled 86 patients. Their median age was 61 years (58, 64 years) and 66 (79%) were male. Of these, 50 patients (58%) survived to day three for full biomarker assessment. NSE concentrations increased in the TTMH group (p=0.02) and TN group (p=0.005) over time, with the increase being significantly more pronounced in the TN group (p(interaction)=0.04). S100b concentrations decreased over time in the TTMH group (p<0.001) but not in the TN group (p=0.68). However, the S100b change over time did not differ between the groups (p(interaction)=0.23). At six months, 23 (59%) TTMH patients had good functional recovery compared with 18 (46%) TN patients. Hospital mortality occurred in 11 (26%) TTMH patients and 15 (37%) TN patients (p=0.31). CONCLUSIONS: In CA patients admitted to the ICU, TTMH was feasible, appeared safe and attenuated the release of NSE compared with TN. These findings justify further investigation of this novel treatment.

Intravenous fluid use after cardiac surgery: a multicentre, prospective, observational study.

BACKGROUND: The optimal strategy for fluid replacement after major surgery remains unclear and there is considerable interest in the investigation of more restrictive fluid regimens. OBJECTIVE: We aimed to establish current practice of fluid administration to patients after cardiac surgery. DESIGN, SETTING AND PARTICIPANTS: A multicentre, prospective observational study, over an 8-week period, of consecutive patients admitted to five intensive care units in New Zealand and Australia. MAIN OUTCOME MEASURES: We collected patient demographic data and details of fluid boluses and all other intravenous (IV) fluids administered in the first 24 hours after ICU admission. RESULTS: We included 235 patients, and 1226 fluid boluses with an average volume of 504 mL/bolus were administered. The median total fluid given for volume expansion in the first 24 hours was 2250mL (interquartile range [IQR], 1250-3500mL) from a median total IV fluid intake of 4493mL/patient (IQR, 2842-5498 mL). The decision to administer a fluid bolus was made 40% of the time by nursing staff, 45% by an ICU resident and 12% by an ICU specialist. The most common reason for fluid administration was hypotension (65%), and crystalloid fluid was used for 65% of the boluses. CONCLUSIONS: We showed that fluid boluses are responsible for a large proportion of the positive fluid balance seen in patients after cardiac surgery. These data justify further study to evaluate whether modification of fluid bolus administration can improve patient outcomes.

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.