A Pilot Randomized Controlled Study of Mild Hypercapnia During Cardiac Surgery With Cardiopulmonary Bypass.

OBJECTIVES: To test whether targeted therapeutic mild hypercapnia (TTMH) would attenuate cerebral oxygen desaturation detected using near-infrared spectroscopy during cardiac surgery requiring cardiopulmonary bypass (CPB). DESIGN: Randomized controlled trials. SETTING: Operating rooms and intensive care unit of tertiary hospital. PARTICIPANTS: The study comprised 30 patients undergoing cardiac surgery with CPB. INTERVENTIONS: Patients were randomly assigned to receive either standard carbon dioxide management (normocapnia) or TTMH (target arterial carbon dioxide partial pressure between 50 and 55 mmHg) throughout the intraoperative period and postoperatively until the onset of spontaneous ventilation. MEASUREMENTS AND MAIN RESULTS: Relevant biochemical and hemodynamic variables were measured, and cerebral tissue oxygen saturation (SctO2) was monitored with near-infrared spectroscopy. Patients were followed-up with neuropsychological testing. Patient demographics between groups were compared using the Fisher exact and Mann-Whitney tests, and SctO2 between groups was compared using repeated measures analysis of variance. The median patient age was 67 years (interquartile range [IQR] 62-72 y), and the median EuroSCORE II was 1.1. The median CPB time was 106 minutes. The mean intraoperative arterial carbon dioxide partial pressure for each patient was significantly higher with TTMH (52.1 mmHg [IQR 49.9-53.9 mmHg] v 40.8 mmHg [IQR 38.7-41.7 mmHg]; p < 0.001) as was pulmonary artery pressure (23.9 mmHg [IQR 22.4-25.3 mmHg] v 18.5 mmHg [IQR 14.8-20.7 mmHg]; p = 0.004). There was no difference in mean percentage change in SctO2 during CPB in the control group for both hemispheres (left: -6.7% v -2.3%; p = 0.110; right: -7.9% v -1.0%; p = 0.120). Compliance with neuropsychological test protocols was poor. However, the proportion of patients with drops in test score >20% was similar between groups in all tests. CONCLUSIONS: TTMH did not increase SctO2 appreciably during CPB but increased pulmonary artery pressures before and after CPB. These findings do not support further investigation of TTMH as a means of improving SctO2 during and after cardiac surgery requiring CPB.

Liberal Glucose Control in ICU Patients With Diabetes: A Before-and-After Study.

OBJECTIVES: To assess the feasibility, biochemical efficacy, and safety of liberal versus conventional glucose control in ICU patients with diabetes. DESIGN: Prospective, open-label, sequential period study. SETTING: A 22-bed mixed ICU of a tertiary hospital in Australia. PATIENTS: We compared 350 consecutive patients with diabetes admitted over 15 months who received liberal glucose control with a preintervention control population of 350 consecutive patients with diabetes who received conventional glucose control. INTERVENTIONS: Liberal control patients received insulin therapy if glucose was greater than 14 mmol/L (target: 10-14 mmol/L [180-252 mg/dL]). Conventional control patients received insulin therapy if glucose was greater than 10 mmol/L (target: 6-10 mmol/L [108-180 mg/dL]). MEASUREMENTS AND MAIN RESULTS: We assessed separation in blood glucose, insulin requirements, occurrence of hypoglycemia (blood glucose ≤ 3.9 mmol/L [70 mg/dL]), creatinine and white cell count levels, and clinical outcomes. The median (interquartile range) time-weighted average blood glucose concentration was significantly higher in the liberal control group (11.0 mmol/L [8.7-12.0 mmol/L]; 198 mg/dL [157-216 mg/dL]) than in the conventional control group (9.6 mmol/L [8.5-11.0 mmol/L]; 173 mg/dL [153-198 mg/dL]; p < 0.001). Overall, 132 liberal control patients (37.7%) and 188 conventional control patients (53.7%) received insulin in ICU (p < 0.001). Hypoglycemia occurred in 6.6% and 8.6%, respectively (p = 0.32). Among 314 patients with glycated hemoglobin A1c greater than or equal to 7%, hypoglycemia occurred in 4.1% and 9.6%, respectively (p = 0.053). Trajectories of creatinine and white cell count were similar in the groups. In multivariable analyses, we found no independent association between glucose control and mortality, duration of mechanical ventilation, or ICU-free days to day 30. CONCLUSIONS: In ICU patients with diabetes, during a period of liberal glucose control, insulin administration, and among patients with hemoglobin A1c greater than or equal to 7%, the prevalence of hypoglycemia was reduced, without negatively affecting serum creatinine, the white cell count response, or other clinical outcomes. (Trial Registration: Australian New Zealand Clinical Trials Registry; ACTRN12615000216516).

Erythropoiesis-stimulating Agents in Critically Ill Trauma Patients: A Systematic Review and Meta-analysis.

OBJECTIVE: To perform a meta-analysis of all relevant randomized controlled trials assessing the effect of erythropoiesis-stimulating agents (ESAs) in critically ill trauma patients. BACKGROUND: ESAs have effects beyond erythropoiesis. The administration of the ESA epoetin alfa to critically ill trauma patients has been associated with a reduction in mortality. METHODS: We performed a systematic review and meta-analysis with trial sequential analysis. We searched Medline, Medline in Process, and other nonindexed citations, EMBASE, and the Cochrane Database from inception until September 9, 2015, for randomized controlled trials comparing ESAs to placebo (or no ESA). RESULTS: We identified 9 eligible studies that randomly assigned 2607 critically ill patients after trauma to an ESA or placebo (or no ESA). Compared with placebo (or no ESA), ESA therapy was associated with a substantial reduction in mortality [risk ratio (RR) 0.63, 95% confidence interval (CI) 0.49-0.79, P = 0.0001, I = 0%). In patients with traumatic brain injury, ESA therapy did not increase the number of patients surviving with moderate disability or good recovery (RR 1.00, 95% CI 0.88-1.15, P = 0.95, I = 0%). With the dosing regimens employed in the included studies, ESA therapy did not increase the risk of lower limb proximal deep venous thrombosis (RR 0.97, 95% CI 0.72-1.29, P = 0.78, I = 0%). CONCLUSIONS: The administration of ESAs to critically ill trauma patients is associated with a significant improvement in mortality without an increase in the rate of lower limb proximal deep venous thrombosis. Given the worldwide public health significance of these findings research to validate or refute them is required.

Near-Infrared Spectroscopy in Adult Cardiac Surgery Patients: A Systematic Review and Meta-Analysis.

OBJECTIVES: To identify the normal baseline preoperative range of cerebral tissue oxygen saturation (SctO2) derived using near-infrared spectroscopy (NIRS) and the efficacy of perioperative interventions designed to modulate SctO2 in cardiac surgical patients. DESIGN: Systematic review and meta-analysis of relevant randomized controlled trials (RCTs) extracted from the Medline, Embase, and Cochrane Central Register of Controlled Trials databases. SETTING: Hospitals performing cardiac surgery. PARTICIPANTS: The study comprised 953 participants from 11 RCTs. INTERVENTIONS: Interventions included the following: (1) SctO2 monitoring protocol compared with no monitoring; (2) use of cardiopulmonary bypass (CPB) compared with no CPB; (3) normothermic CPB compared with hypothermic CPB; (4) glyceryl trinitrate during surgery compared with placebo; (5) midazolam during induction of anesthesia compared with propofol; (6) sevoflurane anesthesia compared with total intravenous anesthesia; (7) sevoflurane anesthesia compared with propofol-based anesthesia; and (8) norepinephrine during CPB compared with phenylephrine. MEASUREMENTS AND MAIN RESULTS: Eleven RCTs with 953 participants measured baseline preoperative SctO2 using NIRS. The pooled mean baseline SctO2 was 66.4% (95% CI 65.0-67.7), generating a reference range of 51.0% to 81.8%. Four interventions (1, 3, 4, and 6 described in the Interventions section above) increased intraoperative SctO2 across the majority of reported time points. Postoperative follow-up of SctO2 occurred in only 1 study, and postoperative cognitive assessment correlating SctO2 with cognitive function was applied in only 4 studies using variable methodology. CONCLUSIONS: The authors have established that reference values for baseline NIRS-derived SctO2 in cardiac surgery patients are varied and have identified interventions that modulate SctO2. This information opens the door to standardized research and interventional studies in this field.

Liberal Versus Conventional Glucose Targets in Critically Ill Diabetic Patients: An Exploratory Safety Cohort Assessment.

OBJECTIVES: To assess the feasibility, safety, and impact on relative hypoglycemia of liberal versus conventional blood glucose concentration targets in critically ill diabetic patients. DESIGN: Prospective, open-label, sequential-period exploratory study. SETTING: A 22-bed multidisciplinary ICU of a tertiary care hospital in Australia. PATIENTS: Eighty adult diabetic patients, 40 from the conventional before period and 40 from the liberal after period. INTERVENTIONS: Blood glucose concentration targets were 6-10 mmol/L during the before period and 10-14 mmol/L during the after period. MEASUREMENTS AND MAIN RESULTS: We used admission glycated hemoglobin to estimate premorbid baseline blood glucose concentration. We defined glycemic distance as the difference between blood glucose concentration in ICU and baseline blood glucose concentration. During the first 48 ICU hours, we recorded absolute (blood glucose concentration, < 3.9 mmol/L) and relative (glycemic distance, > 30% below baseline) hypoglycemia rates, insulin administration, and outcomes. The groups had similar baseline characteristics. We observed a negative glycemic distance in 248 of 488 blood glucose concentrations (50.8%) during the before period and 164 of 485 (33.8%) during the after period (p < 0.001). We detected relative hypoglycemia in 20 (50.0%) and nine (22.5%) patients in the before and after periods, respectively (p = 0.01). On day 1, 50.0% and 16.7% received insulin in the before and after periods (p = 0.007). ICU and hospital length of stay and mortality were similar between groups. CONCLUSIONS: In a safety cohort of critically ill diabetic patients, a blood glucose concentration target of 10-14 mmol/L resulted in fewer episodes of negative glycemic distance or relative hypoglycemia and reduced insulin administration compared with a target of 6-10 mmol/L.

A Pilot Assessment of Carotid and Brachial Artery Blood Flow Estimation Using Ultrasound Doppler in Cardiac Surgery Patients.

OBJECTIVES: To estimate carotid and brachial artery blood flow with Doppler ultrasound in cardiac surgery patients and relate such estimates to cardiac index, lactate levels, and markers of renal function. DESIGN: A prospective observational study. SETTING: A teaching hospital. PARTICIPANTS: Twenty-five elective cardiac surgery patients. INTERVENTIONS: The authors measured bilateral carotid and brachial artery blood flows using Doppler ultrasound and, simultaneously, cardiac index using a pulmonary artery catheter; lactate and serum creatinine levels; and urine output. The relationship between these indices and biomarkers was assessed statistically. MEASUREMENTS AND MAIN RESULTS: Median carotid arterial blood flow was estimated at 0.323 L/min (interquartile ratio [IQR], 0.256-0.429 L/min) on the right and 0.308 L/min (IQR, 0.247-0.376 L/min) on the left at baseline. Median brachial arterial blood flow was estimated at 0.063 L/min (IQR, 0.039-0.115 L/min) on the right and 0.063 L/min (IQR, 0.039-0.081 L/min) on the left at baseline. There was a weak correlation between right- and left-sided flows (brachial: rho = 0.285; carotid: rho = 0.384) and between brachial and carotid flow (right: rho = 0.135, left: rho = 0.225). There also was a weak correlation between cardiac index and brachial flow (right: rho = 0.215; left: rho = 0.320) and carotid flow (left: rho = 0.159) immediately after surgery, and no correlation 1 day after surgery (right brachial: rho = -0.010; left brachial: rho = -0.064; left carotid: rho = -0.060). There were no significant correlations between carotid or brachial flows and lactate and serum creatinine levels or urine output. CONCLUSIONS: In cardiac surgery patients, Doppler-estimated carotid and brachial arterial blood flows have only a weak correlation with cardiac index and no correlation with lactate or creatinine levels or urine output. Thus, Doppler estimation of these blood flows cannot be used to provide noninvasive estimates of cardiac index in patients after cardiac surgery.

Fluid Bolus Therapy-Based Resuscitation for Severe Sepsis in Hospitalized Children: A Systematic Review.

OBJECTIVES: To review systematically data from randomized and nonrandomized studies of fluid bolus therapy in hospitalized children with septic shock. DATA SOURCES: Medline, EMBASE, and Cochrane Central Register of Controlled Trials. STUDY SELECTION: We searched for randomized controlled studies of fluid bolus therapy in children with severe sepsis. We identified retrospective, prospective, and observational studies. We excluded studies of severe sepsis/septic shock due to a specific microbiological etiology, neonatal studies, and studies where advanced supportive therapies were unavailable. DATA EXTRACTION: Two authors screened articles for inclusion. DATA SYNTHESIS: We identified and analyzed three randomized controlled trials and eight nonrandomized studies. Heterogeneity precluded meta-analysis. Two single-center Indian studies and one Brazilian study assessed three different fluid bolus therapy regimens in small cohorts with different populations, physiological triggers, and physiological and clinical outcomes. No randomized controlled trials compared fluid bolus therapy with alternative interventions, such as vasopressors. The nonrandomized studies were heterogeneous in populations, methodology, and outcome measures. No observed physiological differences were identified based on volume of fluid bolus therapy. CONCLUSIONS: There are only limited data to support the use of fluid bolus therapy in hospitalized children. Prospective observational data and randomized controlled trials are urgently needed to evaluate this therapy in resource rich settings.

Urinary Neutrophil Gelatinase-Associated Lipocalin as Predictor of Short- or Long-Term Outcomes in Cardiac Surgery Patients.

OBJECTIVES: To determine the ability of urinary neutrophil gelatinase-associated lipocalin (uNGAL) to predict cardiac surgery-associated acute kidney injury (CSA-AKI), continuous renal replacement therapy (CRRT), mortality, and a composite outcome of major adverse kidney events at 365 days (MAKE365), and to investigate the influence of cardiopulmonary bypass (CPB) on NGAL release. DESIGN: A prospective observational study. SETTING: A single-center university hospital. PARTICIPANTS: A cohort of 288 adult cardiac surgery patients. INTERVENTIONS: uNGAL was measured at baseline, immediately after surgery, and on days 1 and 2 postoperatively. The authors used the recent Kidney Disease Improving Global Outcomes consensus criteria to define CSA-AKI. MEASUREMENTS AND MAIN RESULTS: CSA-AKI occurred in 36.1% of patients. uNGAL rapidly became significantly higher in patients who developed AKI, with peak value immediately after surgery (349.9 [76.6-1446.6] v 90.1 [20.8-328] ng/mg creatinine; p<0.001). No measure of uNGAL (peak, postsurgery, day 1 or 2 postsurgery) accurately predicted CSA-AKI, CRRT, mortality, or MAKE365. However, immediately after surgery, CPB induced greater uNGAL release compared with off-pump surgery (265.5 µmol/L [71-989.6] v 48.7 ng/mg creatinine [17-129.8]; p<0.001). Moreover, such early uNGAL release correlated with CPB duration (r = 0.505; p<0.001) but not with peak serum creatinine values on day 3 or 7 after surgery. CONCLUSIONS: uNGAL had a limited predictive ability for CSA-AKI or other relevant clinical outcomes after cardiac surgery and appeared to be more closely related to the use and duration of CPB. Thus, its levels may represent the aggregate effect of an inflammatory response to CPB as well as a renal response to cardiac surgery and inflammation.

Stress hyperlactatemia modifies the relationship between stress hyperglycemia and outcome: a retrospective observational study.

OBJECTIVE: To study the effect of stress hyperlactatemia on the association between stress hyperglycemia and mortality. DESIGN: Retrospective cross-sectional observation study. SETTING: Three ICUs using arterial blood gases with simultaneous glucose and lactate measurements during ICU stay. PATIENTS: Cohort of 7,925 consecutive critically ill patients. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We analyzed 152,349 simultaneous measurements of glucose and lactate. We performed multivariable analysis to study the association of different metrics of glucose and lactate with hospital mortality. On day 1, first (p = 0.013), highest (p = 0.001), mean (p = 0.019), and time-weighted mean (p = 0.010) glucose levels were associated with increased mortality. A similar, but stronger, association was seen for corresponding lactate metrics (p < 0.0001 for all). However, once glucose and lactate metrics were entered into the multivariable logistic regression model simultaneously, all measures of glycemia ceased to be significantly associated with hospital mortality regardless of the metrics being used (first, highest, mean, time-weighed; p > 0.05 for all), whereas all lactate metrics remained associated with mortality (p < 0.0001 for all). In patients with at least one episode of moderate hypoglycemia (glucose ≤ 3.9 mmol/L), glucose metrics were not associated with mortality when studied separately (p > 0.05 for all), whereas lactate was (p < 0.05 for all), but when incorporated into a model simultaneously, highest glucose on day 1 was associated with mortality (p< 0.05), but not other glucose metrics (p > 0.05), whereas all lactate metrics remained associated with mortality (p < 0.05 for all). CONCLUSIONS: Stress hyperlactatemia modifies the relationship between hyperglycemia and mortality. There is no independent association between hyperglycemia and mortality once lactate levels are considered.

Conservative oxygen therapy in mechanically ventilated patients: a pilot before-and-after trial.

OBJECTIVES: To assess the feasibility and safety of a conservative approach to oxygen therapy in mechanically ventilated ICU patients. DESIGN: Pilot prospective before-and-after study. SETTING: A 22-bed multidisciplinary ICU of a tertiary care hospital in Australia. PATIENTS: A total of 105 adult (18 years old or older) patients required mechanical ventilation for more than 48 hours: 51 patients during the "conventional" before period and 54 after a change to "conservative" oxygen therapy. INTERVENTIONS: Implementation of a conservative approach to oxygen therapy (target SpO2 of 90-92%). MEASUREMENTS AND MAIN RESULTS: We collected 3,169 datasets on 799 mechanical ventilation days. During conservative oxygen therapy the median time-weighted average SpO2 on mechanical ventilation was 95.5% (interquartile range, 94.0-97.3) versus 98.4% (97.3-99.1) (p < 0.001) during conventional therapy. The median PaO2 was 83 torr (71-94) versus 107 torr (94-131) (p < 0.001) with a change to a median FIO2 of 0.27 (0.24-0.30) versus 0.40 (0.35-0.44) (p < 0.001). Conservative oxygen therapy decreased the median total amount of oxygen delivered during mechanical ventilation by about two thirds (15,580 L [8,263-29,351 L] vs 5,122 L [1,837-10,499 L]; p < 0.001). The evolution of the PaO2/FIO2 ratio was similar during the two periods, and there were no difference in any other biochemical or clinical outcomes. CONCLUSIONS: Conservative oxygen therapy in mechanically ventilated ICU patients was feasible and free of adverse biochemical, physiological, or clinical outcomes while allowing a marked decrease in excess oxygen exposure. Our study supports the safety and feasibility of future pilot randomized controlled trials of conventional compared with conservative oxygen therapy.

Physiological changes after fluid bolus therapy in sepsis: a systematic review of contemporary data.

Fluid bolus therapy (FBT) is a standard of care in the management of the septic, hypotensive, tachycardic and/or oliguric patient. However, contemporary evidence for FBT improving patient-centred outcomes is scant. Moreover, its physiological effects in contemporary ICU environments and populations are poorly understood. Using three electronic databases, we identified all studies describing FBT between January 2010 and December 2013. We found 33 studies describing 41 boluses. No randomised controlled trials compared FBT with alternative interventions, such as vasopressors. The median fluid bolus was 500 ml (range 100 to 1,000 ml) administered over 30 minutes (range 10 to 60 minutes) and the most commonly administered fluid was 0.9% sodium chloride solution. In 19 studies, a predetermined physiological trigger initiated FBT. Although 17 studies describe the temporal course of physiological changes after FBT in 31 patient groups, only three studies describe the physiological changes at 60 minutes, and only one study beyond this point. No studies related the physiological changes after FBT with clinically relevant outcomes. There is a clear need for at least obtaining randomised controlled evidence for the physiological effects of FBT in patients with severe sepsis and septic shock beyond the period immediately after its administration.

The microbiological and clinical outcome of guide wire exchanged versus newly inserted antimicrobial surface treated central venous catheters.

INTRODUCTION: The management of suspected central venous catheter (CVC)-related sepsis by guide wire exchange (GWX) is not recommended. However, GWX for new antimicrobial surface treated (AST) triple lumen CVCs has never been studied. We aimed to compare the microbiological outcome of triple lumen AST CVCs inserted by GWX (GWX-CVCs) with newly inserted triple lumen AST CVCs (NI-CVCs). METHODS: We studied a cohort of 145 consecutive patients with GWX-CVCs and contemporaneous site-matched control cohort of 163 patients with NI-CVCs in a tertiary intensive care unit (ICU). RESULTS: GWX-CVC and NI-CVC patients were similar for mean age (58.7 vs. 62.2 years), gender (88 (60.7%) vs. 98 (60.5%) male) and illness severity on admission (mean Acute Physiology and Chronic Health Evaluation (APACHE) III: 71.3 vs. 72.2). However, GWX patients had longer median ICU lengths of stay (12.2 vs. 4.4 days; P < 0.001) and median hospital lengths of stay (30.7 vs. 18.0 days; P < 0.001). There was no significant difference with regard to the number of CVC tips with bacterial or fungal pathogen colonization among GWX-CVCs vs. NI-CVCs (5 (2.5%) vs. 6 (7.4%); P = 0.90). Catheter-associated blood stream infection (CA-BSI) occurred in 2 (1.4%) GWX patients compared with 3 (1.8%) NI-CVC patients (P = 0.75). There was no significant difference in hospital mortality (35 (24.1%) vs. 48 (29.4%); P = 0.29). CONCLUSIONS: GWX-CVCs and NI-CVCs had similar rates of tip colonization at removal, CA-BSI and mortality. If the CVC removed by GWX is colonized, a new CVC must then be inserted at another site. In selected ICU patients at higher central vein puncture risk receiving AST CVCs GWX may be an acceptable initial approach to line insertion.

Breaches of pre-medical emergency team call criteria in an Australian hospital.

Objectives and outcomes: To evaluate the 24hrs before medical emergency team (MET) calls to examine: 1) the frequency, nature, and timing of pre-MET criteria breaches; 2) differences in characteristics and outcomes between patients who did and didn't experience pre-MET breaches. Design: Retrospective observational study November 2020-June 2021. Setting: Tertiary referral Australian hospital. Participants: Adults (≥18 years) experiencing MET calls. Results: Breaches in pre-MET criteria occurred prior to 1886/2255 (83.6%) MET calls, and 1038/1281 (81.0%) of the first MET calls. Patients with pre-MET breaches were older (median [IQR] 72 [57-81] vs 66 [56-77] yrs), more likely to be admitted from home (87.8% vs 81.9%) and via the emergency department (73.0% vs 50.2%), but less likely to be for full resuscitation after (67.3% vs 76.5%) the MET. The three most common pre-MET breaches were low SpO2 (48.0%), high pulse rate (39.8%), and low systolic blood pressure (29.0%) which were present for a median (IQR) of 15.4 (7.5-20.8), 13.2 (4.3-21.0), and 12.6 (3.5-20.1) hrs before the MET call, respectively. Patients with pre-MET breaches were more likely to need intensive care admission within 24 h (15.6 vs 11.9%), have repeat MET calls (33.3 vs 24.7%), and die in hospital (15.8 vs 9.9%). Conclusions: Four-fifths of MET calls were preceded by pre-MET criteria breaches, which were present for many hours. Such patients were older, had more limits of treatment, and experienced worse outcomes. There is a need to improve goals of care documentation and pre-MET management of clinical deterioration.

The Australian approach to peri-operative fluid balance.

PURPOSE OF REVIEW: The role of fluid balance as an important contributor to patient morbidity and mortality in the peri-operative period is only now being understood. Numerous studies in disparate populations undergoing different surgeries suggest that. RECENT FINDINGS: There is wide disparity in fluid administration regimen between speciality, country, and clinician. Recent meta-analyses of published studies have shown that restrictive fluid administration strategies may improve patient-centred outcomes when compared to liberal regimens. Current evidence suggests a significant role for fluid accumulation in the development of peri-operative complications. Fluid balance is best achieved using goal-directed techniques. The evidence base is, at present, sub-optimal, with a paucity of level 1 evidence for clinical decision-making. SUMMARY: In the absence of level 1 evidence it is difficult to make firm recommendations about practice, though observational and single-centre data suggest a significant survival advantage may be conferred by the peri-operative administration of fluids to monitored physiological targets only. The Australian approach to peri-operative fluid management is to create level 1 evidence. To this end, the development of a large multicentre randomized controlled trial of peri-operative fluid administration is underway.

Acute kidney injury: how can we facilitate recovery?

PURPOSE OF REVIEW: Successful renal recovery is a key goal of patient management during acute kidney injury in critically ill patients. However, limited information exists to guide clinicians as to what interventions might either decrease or increase the likelihood of renal recovery and especially renal recovery to dialysis independence. The purpose of this review is to analyse recent data and help clinicians with relevant therapeutic choices. RECENT FINDINGS: Two large trials, the Acute Renal Failure Trial Network (ATN) and Randomized Evaluation of Normal versus Augmented Level Renal Replacement Therapy (RENAL), provide important evidence on the possible impact of choice of renal replacement therapy on renal recovery to dialysis independence. In the ATN trial in which intermittent haemodialysis (IHD) was delivered 5077 times, continued dialysis dependence by day 28 occurred in 45.2% of survivors, whereas in the RENAL study in which IHD was used 314 times, dialysis dependence at 28 days was 13.3%. These striking differences in favour of using continuous renal replacement therapy are supported by observational studies and a randomized controlled trial. Similarly the association of a positive fluid balance with poor outcomes has now been supported by multiple observational studies and multivariable logistic regression analysis. Both use of IHD and a positive fluid balance can delay renal recovery. SUMMARY: Available evidence from randomized controlled trials and comparative analysis of their results as well as data from large observational studies suggest that the avoidance of IHD and of a positive fluid balance are likely to increase the speed of renal recovery and may prevent end-stage renal failure in selected high-risk patients with acute kidney injury.

Accuracy of non-invasive body temperature measurement methods in adult patients admitted to the intensive care unit: a systematic review and meta-analysis.

Objective: Non-invasive thermometers are widely used in both clinical practice and trials to estimate core temperature. We aimed to investigate their accuracy and precision in patients admitted to the intensive care unit (ICU). Study design: Systematic review and meta-analysis. Data sources: We searched MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials to identify all relevant studies from 1966 to 2017. We selected published trials that reported the accuracy and precision of non-invasive peripheral thermometers (index test) in ICU patients compared with intravascular temperature measurement (reference test). The extracted data included the study design and setting, authors, study population, devices, and body temperature measurements. Methods: Two reviewers performed the initial search, selected studies, and extracted data. Study quality was assessed using the QUADAS-2 tool. Pooled estimates of the mean bias between index and reference tests and the standard deviation of mean bias were synthesised using DerSimonian and Laird random effects meta-analyses. Results: We included 13 cohort studies (632 patients, 105 375 measurements). Axillary, tympanic infrared and zero heat flux thermometers all underestimated intravascular temperature. Only oesophageal measurements showed clinically acceptable accuracy. We found an insufficient number of studies to assess precision for any technique. Study heterogeneity was high (99-100%). Risk of bias for the index test was unclear, mostly because of no device calibration or control for confounders. Conclusions: Compared with the gold standard of intravascular temperature measurement, non-invasive peripheral thermometers have low accuracy. This makes their clinical and trial-related use in ICU patients unreliable and potentially misleading.

Accuracy of non-invasive body temperature measurement methods in critically ill patients: a prospective, bicentric, observational study.

Objective: The accuracy of different non-invasive body temperature measurement methods in intensive care unit (ICU) patients is uncertain. We aimed to study the accuracy of three commonly used methods. Design: Prospective observational study. Setting: ICUs of two tertiary Australian hospitals. Participants: Critically ill patients admitted to the ICU. Interventions: Invasive (intravascular and intra-urinary bladder catheter) and non-invasive (axillary chemical dot, tympanic infrared, and temporal scanner) body temperature measurements were taken at study inclusion and every 4 hours for the following 72 hours. Main outcome measures: Accuracy of non-invasive body temperature measurement methods was assessed by the Bland-Altman approach, accounting for repeated measurements and significant explanatory variables that were identified by regression analysis. Clinical adequacy was set at limits of agreement (LoA) of 1°C compared with core temperature. Results: We studied 50 consecutive critically ill patients who were mainly admitted to the ICU after cardiac surgery. From over 375 observations, invasive core temperature (mostly pulmonary artery catheter) ranged from 33.9°C to 39°C. On average, the LoA between invasive and non-invasive measurements methods were about 3°C. The temporal scanner showed the worst performance in estimating core temperature (bias, 0.66°C; LoA, -1.23°C, +2.55°C), followed by tympanic infrared (bias, 0.44°C; LoA, -1.73°C, +2.61°C) and axillary chemical dot methods (bias, 0.32°C; LoA, -1.64°C, +2.28°C). No methods achieved clinical adequacy even accounting for significant explanatory variables. Conclusions: The axillary chemical dot, tympanic infrared and temporal scanner methods are inaccurate measures of core temperature in ICU patients. These non-invasive methods appeared unreliable for use in ICU patients.

Haemodynamic effect of a 20% albumin fluid bolus in post-cardiac surgery patients.

OBJECTIVE: To study the cardiovascular effect over 30 minutes following the end of fluid bolus therapy (FBT) with 20% albumin in patients after cardiac surgery. DESIGN: Prospective observational study. SETTING: Intensive care unit of a tertiary university-affiliated hospital. PARTICIPANTS: Twenty post-cardiac surgery mechanically ventilated patients with a clinical decision to administer FBT. INTERVENTION: FBT with a 100 mL bolus of 20% albumin. MAIN OUTCOME MEASURES: Cardiac index (CI) response was defined by a ≥ 15% increase, while mean arterial pressure (MAP) response was defined by a ≥ 10% increase. RESULTS: The most common indication for FBT was hypotension (40%). Median duration of infusion was 7 minutes (interquartile range [IQR], 3-9 min). At the end of FBT, five patients (25%) showed a CI response, which increased to almost half in the following 30 minutes and dissipated in one patient. MAP response occurred in 11 patients (55%) and dissipated in five patients (45%) by a median of 6 minutes (IQR, 6-10 min). CI and MAP responses coexisted in four patients (20%). An intrabolus MAP response occurred in 17 patients (85%) but dissipated in 11 patients (65%) within a median of 7 minutes (IQR, 2-11 min). On regression analysis, faster fluid bolus administration predicted MAP increase at the end of the bolus. CONCLUSION: In post-cardiac surgery patients, CI response to 20% albumin FBT was not congruous with MAP response over 30 minutes. Although hypotension was the main indication for FBT and a MAP response occurred in most of patients, such response was maximal during the bolus, dissipated in a few minutes, and was dissociated from the CI response.