Hypothermia versus Normothermia after Out-of-Hospital Cardiac Arrest.

BACKGROUND: Targeted temperature management is recommended for patients after cardiac arrest, but the supporting evidence is of low certainty. METHODS: In an open-label trial with blinded assessment of outcomes, we randomly assigned 1900 adults with coma who had had an out-of-hospital cardiac arrest of presumed cardiac or unknown cause to undergo targeted hypothermia at 33°C, followed by controlled rewarming, or targeted normothermia with early treatment of fever (body temperature, ≥37.8°C). The primary outcome was death from any cause at 6 months. Secondary outcomes included functional outcome at 6 months as assessed with the modified Rankin scale. Prespecified subgroups were defined according to sex, age, initial cardiac rhythm, time to return of spontaneous circulation, and presence or absence of shock on admission. Prespecified adverse events were pneumonia, sepsis, bleeding, arrhythmia resulting in hemodynamic compromise, and skin complications related to the temperature management device. RESULTS: A total of 1850 patients were evaluated for the primary outcome. At 6 months, 465 of 925 patients (50%) in the hypothermia group had died, as compared with 446 of 925 (48%) in the normothermia group (relative risk with hypothermia, 1.04; 95% confidence interval [CI], 0.94 to 1.14; P = 0.37). Of the 1747 patients in whom the functional outcome was assessed, 488 of 881 (55%) in the hypothermia group had moderately severe disability or worse (modified Rankin scale score ≥4), as compared with 479 of 866 (55%) in the normothermia group (relative risk with hypothermia, 1.00; 95% CI, 0.92 to 1.09). Outcomes were consistent in the prespecified subgroups. Arrhythmia resulting in hemodynamic compromise was more common in the hypothermia group than in the normothermia group (24% vs. 17%, P<0.001). The incidence of other adverse events did not differ significantly between the two groups. CONCLUSIONS: In patients with coma after out-of-hospital cardiac arrest, targeted hypothermia did not lead to a lower incidence of death by 6 months than targeted normothermia. (Funded by the Swedish Research Council and others; TTM2 ClinicalTrials.gov number, NCT02908308.).

CaCl2-Citrate Regional Anticoagulation with Continuous Veno-Venous Haemodialysis Leads to Unwanted Chloride Loading Compared to Continuous Veno-Venous Hemofiltration with Systemic Anticoagulation.

INTRODUCTION: Chloride transfers during continuous renal replacement therapy (CRRT) have not been adequately described and may differ based on CRRT technique. We aimed to measure chloride mass transfer (JS,Cl) during CRRT and identify associated determinants. METHODS: We performed a two-centre, prospective, observational study in France and Australia in ICU patients with CRRT initiated for <24 h. Patients received continuous veno-venous hemofiltration (CVVH) or continuous veno-venous haemodialysis (CVVHD, with citrate-CaCl2 regional anticoagulation). Over a 24 h period, plasma and effluent chloride concentrations were measured every 4 h to compute chloride mass transfer (JS,Cl, in mmol.min-1) using a modality-specific model, with negative value indicating chloride transfer towards the patient. Secondary outcomes were the identification of CRRT settings associated with JS,Cl (using multivariate mixed effects regression). Results are presented with median (interquartile range). RESULTS: Between February 2021 and August 2022, we enrolled 37 patients (64 [56-71] years, 67% male), for a total of 20 CVVHD and 20 CVVH sessions. Over 24 h, plasma chloride concentrations were significantly higher, and JS,Cl significantly lower during CVVHD, compared to CVVH (-0.10 [-0.33 to 0.15] vs. 0.01 [-0.10 to 0.13] mmol.min-1, p < 0.05). With both modalities, net ultrafiltration (QUFNET) and plasma chloride concentrations were the principal determinants of JS,Cl, with higher QUFNET being associated with an increase in JS,Cl during CVVHD. Also, CVVHD sessions demonstrated a concentration gradient between the plasma and the effluent chamber of -6 [-9 to -4] mmol.L-1. Finally, CaCl2 reinjection during CVVHD accounted for 35% [32-60%] of total JS,Cl in sessions with a negative JS,Cl. CONCLUSION: Compared to CVVH, CVVHD with regional citrate anticoagulation was associated with greater chloride mass transfer to the patient and higher plasma chloride concentrations. This was due to high dialysate chloride concentrations and CaCl2 reinjection. This effect could only be controlled by high net ultrafiltration flow rates.

The effect of age on clinical dose equivalency of fentanyl and morphine analgosedation in mechanically ventilated patients: Findings from the ANALGESIC trial.

BACKGROUND: The dose equivalency of fentanyl vs. morphine is widely considered to be approximately 1:100. However, little is known about the effect of age on this ratio when these agents are used as infusions for analgosedation. OBJECTIVES: To assess the impact of age on the clinical dose equivalency of fentanyl and morphine when used as infusions for analgosedation in mechanically ventilated intensive care unit patients. METHODS: We performed a post hoc analysis of the Assessment of Opioid Administration to Lead to Analgesic Effects and Sedation in Intensive Care (ANALGESIC) cluster randomised crossover trial of fentanyl and morphine infusions for analgosedation. Dose and analgosedative clinical equivalency of fentanyl and morphine were assessed by age and by using different body-size descriptors. RESULTS: We studied 663 patients (338 fentanyl, 325 morphine). Median (interquartile range) hourly dose of fentanyl and morphine were 58.1 (40.0-89.2) mcg and 3400 (2200-5000) mcg, respectively. The ratio of total dose of fentanyl:morphine was 1:93 in the 18- to 29-year-old group and 1:25 in the ≥80-year-old group (p = 0.015), respectively, with fentanyl becoming relatively less clinically effective as age increased. This effect was also seen when comparing dosing by different body-size descriptors with the strongest age-related change when using body surface area as body-size descriptor (p = 0.009). CONCLUSION: The analgosedative clinical dose equivalency of fentanyl vs. morphine is heterogeneous when used as infusions for analgosedation, with fentanyl becoming relatively less clinically effective as age increases. This information can help guide prescription of these agents during transition from one agent to the other in critically ill patients.

Mega-dose sodium ascorbate: a pilot, single-dose, physiological effect, double-blind, randomized, controlled trial.

BACKGROUND: Mega-dose sodium ascorbate (NaAscorbate) appears beneficial in experimental sepsis. However, its physiological effects in patients with septic shock are unknown. METHODS: We conducted a pilot, single-dose, double-blind, randomized controlled trial. We enrolled patients with septic shock within 24 h of diagnosis. We randomly assigned them to receive a single mega-dose of NaAscorbate (30 g over 1 h followed by 30 g over 5 h) or placebo (vehicle). The primary outcome was the total 24 h urine output (UO) from the beginning of the study treatment. Secondary outcomes included the time course of the progressive cumulative UO, vasopressor dose, and sequential organ failure assessment (SOFA) score. RESULTS: We enrolled 30 patients (15 patients in each arm). The mean (95% confidence interval) total 24-h UO was 2056 (1520-2593) ml with placebo and 2948 (2181-3715) ml with NaAscorbate (mean difference 891.5, 95% confidence interval [- 2.1 to 1785.2], P = 0.051). Moreover, the progressive cumulative UO was greater over time on linear mixed modelling with NaAscorbate (P < 0.001). Vasopressor dose and SOFA score changes over time showed faster reductions with NaAscorbate (P < 0.001 and P = 0.042). The sodium level, however, increased more over time with NaAscorbate (P < 0.001). There was no statistical difference in other clinical outcomes. CONCLUSION: In patients with septic shock, mega-dose NaAscorbate did not significantly increase cumulative 24-h UO. However, it induced a significantly greater increase in UO and a greater reduction in vasopressor dose and SOFA score over time. One episode of hypernatremia and one of hemolysis were observed in the NaAscorbate group. These findings support further cautious investigation of this novel intervention. Trial registration Australian New Zealand Clinical Trial Registry (ACTRN12620000651987), Date registered June/5/2020.

Evaluation of ferritin and the ferritin index as prognostic biomarkers in septic shock.

BACKGROUND: Ferritin, an acute phase reactant, and the ferritin index (FI = observed ferritin level/upper limit of normal level for age and sex) may be prognostic biomarkers in septic shock and cardiac surgery patients. OBJECTIVE: The purpose of this exploratory study is to assess the outcome associations of ferritin and FI levels in septic shock compared to post-cardiac surgery patients. DESIGN: This was a prospective, double-centre, observational study. SETTING: The study setting involved two adult intensive care units (ICUs) in Victoria, Australia. PARTICIPANTS: Sixty-one septic shock and 30 post-cardiac surgery patients participated in this study. MAIN OUTCOME MEASURES: We measured ferritin and FI on ICU admission (T1) and 24 h later (T2) to assess its correlation with mortality, illness severity, and hospital length of stay (LOS). RESULTS: The baseline characteristics of patients in the septic shock group and cardiac surgery group were similar apart from illness severity scores (APACHE III and modified SOFA score). Septic shock patients had more physiological derangements as well as greater use and higher doses of norepinephrine at both T1 and T2. Septic shock patients had significantly higher median ferritin levels (372 µg/L versus 198 µg/L; p < 0.001 at T1, 457 µg/L versus 264 µg/L; p = 0.001 at T2) than post-cardiac surgery patients. Ferritin levels, however, did not have a linear correlation with illness severity or hospital mortality. Instead, there was an association between high ferritin levels at T2 and longer ICU (p = 0.017) and hospital LOS (p = 0.013). Females with septic shock had significantly higher FI (p < 0.001 at T1, p = 0.004 at T2) than males. CONCLUSION: In septic shock patients, ferritin levels and FI were twice the level compared to post-cardiac surgery patients. Both had no association with mortality, but levels above the median at 24 h were associated with longer ICU and hospital LOS.

Long-Term Functional Outcome and Quality of Life Following In-Hospital Cardiac Arrest-A Longitudinal Cohort Study.

OBJECTIVES: To evaluate the functional outcome and health-related quality of life of in-hospital cardiac arrest survivors at 6 and 12 months. DESIGN: A longitudinal cohort study. SETTING: Seven metropolitan hospitals in Australia. PATIENTS: Data were collected for hospitalized adults (≥ 18 yr) who experienced in-hospital cardiac arrest, defined as "a period of unresponsiveness, with no observed respiratory effort and the commencement of external cardiac compressions." INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Prior to hospital discharge, patients were approached for consent to participate in 6-month and 12-month telephone interviews. Outcomes included the modified Rankin Scale, Barthel Index, Euro-Quality of Life 5 Dimension 5 Level, return to work and hospital readmissions. Forty-eight patients (80%) consented to follow-up interviews. The mean age of participants was 67.2 (± 15.3) years, and 33 of 48 (68.8%) were male. Good functional outcome (modified Rankin Scale score ≤ 3) was reported by 31 of 37 participants (83.8%) at 6 months and 30 of 33 (90.9%) at 12 months. The median Euro-Quality of Life-5D index value was 0.73 (0.33-0.84) at 6 months and 0.76 (0.47-0.88) at 12 months. The median Euro-Quality of Life-Visual Analogue Scale score at 6 months was 70 (55-80) and 75 (50-87.5) at 12 months. Problems in all Euro-Quality of Life-5D-5 L dimension were reported frequently at both time points. Hospital readmission was reported by 23 of 37 patients (62.2%) at 6 months and 16 of 33 (48.5%) at 12 months. Less than half of previously working participants had returned to work by 12 months. CONCLUSIONS: The majority of in-hospital cardiac arrest survivors had a good functional outcome and health-related quality of life at 6 months, and this was largely unchanged at 12 months. Despite this, many reported problems with mobility, self-care, usual activities, pain, and anxiety/depression. Return to work rates was low, and hospital readmissions were common.

A Phase II Cluster-Crossover Randomized Trial of Fentanyl versus Morphine for Analgosedation in Mechanically Ventilated Patients.

Rationale: The continuous infusion of fentanyl or morphine is often prescribed to assist with analgesia and sedation (analgosedation) during mechanical ventilation. Objectives: To compare the effect of fentanyl versus morphine on patient-centered outcomes in ventilated patients. Methods: We conducted a cluster-randomized, cluster-crossover trial between July 2019 and August 2020 in two adult ICUs. We compared two continuous infusion regimens (fentanyl versus morphine). One ICU was randomized to the fentanyl-morphine sequence and the other to the morphine-fentanyl sequence. The primary outcome was the number of ventilator-free days at Day 28. Secondary outcomes included, among others, duration of mechanical ventilation in survivors and ICU-free days at Day 28. Measurements and Main Results: Via cluster allocation, we randomized 737 patients. Of these, 56 were excluded because of the opt-out consent process, leaving 681 (344 to fentanyl and 337 to morphine) for primary analysis (median [interquartile range] age, 59 [44-69] years). Median ventilator-free days at Day 28 were 26.1 (20.7-27.3) in the fentanyl versus 25.3 (19.1-27.2) in the morphine group (median difference, 0.79 [95% confidence interval, 0.31 to 1.28], P = 0.001). ICU-free days were greater (P < 0.001) and length of stay in the ICU for survivors shorter (P < 0.001) in the fentanyl group. All other secondary outcomes were not statistically different by treatment group. Conclusions: Among adult patients requiring mechanical ventilation, compared with morphine, fentanyl infusion significantly increased the median number of ventilator-free days at Day 28. The choice of opioid infusion agent may affect clinical outcomes and requires further investigation.

Registrar triage, communication and moral distress during end-of-life care rapid response team calls in a teaching hospital.

BACKGROUND: Approximately one-third of rapid response teams (RRT) involve end-of-life care (EOLC) issues. Intensive care unit (ICU) registrar experience in such calls is underinvestigated. AIMS: To evaluate the proportion of RRT calls triaged as relating to EOLC issues, issues around communication regarding prognostication, registrar self-reported moral distress and associations between RRT EOLC classification and patient outcomes. METHODS: Prospective observational study of RRT calls in a tertiary referrals hospital between December 2016 and January 2017 using a standardised case report form and data from an electronic RRT database. RESULTS: There were 401 RRT calls in the study period, and data were available for 270 (67%) calls, of which 72%, 10% and 18% were triaged as 'obviously not EOLC call', 'obvious EOLC call' and 'uncertain EOLC call' respectively. Most discussions regarding prognostication occurred between registrars, and more than half (55%) were with a covering doctor. Consensus on prognostication was achieved in 93% cases. Registrars reported distress in 19% of calls that obviously related to EOLC and 22% of calls that were uncertain, compared with <1% of calls that were obviously not relating to EOLC. Inhospital mortality was 6%, 67% and 39% for obviously not EOLC, obvious EOLC and uncertain EOLC calls respectively. CONCLUSIONS: EOLC issues occur commonly in RRT calls and are often associated with moral distress to ICU registrars. Although consensus on prognostication is usually achieved, conversations often involve covering doctors. These issues impact on the ICU registrar experience of RRT calls and require further exploration.

The hemodynamic effects of warm versus room-temperature crystalloid fluid bolus therapy in post-cardiac surgery patients.

INTRODUCTION: The contribution of fluid temperature to the effect of crystalloid fluid bolus therapy (FBT) in post-cardiac surgery patients is unknown. We evaluated the hemodynamic effects of FBT with fluid warmed to 40°C (warm FBT) versus room-temperature fluid. METHODS: In this single centre prospective before-and-after study, we evaluated the effects of 500 ml of warm versus room-temperature compound sodium lactate administered over <30 minutes, in 50 cardiac surgery patients admitted to ICU. We recorded hemodynamics continuous before and for 30 minutes after the first FBT. We defined CI responsiveness (CI-R) as an CI increase >15% of baseline immediately after FBT and effect dissipation if the CI returned to <5% of baseline and MAP responsiveness as >10% increase and dissipation as return to <3 mmHg of baseline. RESULTS: Hypotension (56%) and low CI (40%) typically triggered FBT. Temperature decreased >0.3°C in 13 (52%) patients after room-temperature FBT versus 0 (0%) after warm FBT (p < 0.01). CI and MAP responsiveness was similar (16 [64%] versus 11 [44%], p = 0.15 and 15 [60%] versus 17 [68%], p = 0.77, respectively). Among CI responders, CI increased more with room-temperature FBT (+0.6 [IQR, 0.5-1.1] versus +0.5 [IQR, 0.4-0.6] L/min/m2, p = 0.01). However, dissipation was more common after room-temperature versus warm FBT (9/16 [56%] versus 1/11 [9%], p = 0.02). CONCLUSION: In postoperative cardiac surgery patients, warm FBT preserved core temperature and induced smaller but more sustained CI increases among responders. Fluid temperature appears to impact both core temperature and the duration of CI response.

The Effect of Renal Replacement Therapy and Antibiotic Dose on Antibiotic Concentrations in Critically Ill Patients: Data From the Multinational Sampling Antibiotics in Renal Replacement Therapy Study.

BACKGROUND: The optimal dosing of antibiotics in critically ill patients receiving renal replacement therapy (RRT) remains unclear. In this study, we describe the variability in RRT techniques and antibiotic dosing in critically ill patients receiving RRT and relate observed trough antibiotic concentrations to optimal targets. METHODS: We performed a prospective, observational, multinational, pharmacokinetic study in 29 intensive care units from 14 countries. We collected demographic, clinical, and RRT data. We measured trough antibiotic concentrations of meropenem, piperacillin-tazobactam, and vancomycin and related them to high- and low-target trough concentrations. RESULTS: We studied 381 patients and obtained 508 trough antibiotic concentrations. There was wide variability (4-8-fold) in antibiotic dosing regimens, RRT prescription, and estimated endogenous renal function. The overall median estimated total renal clearance (eTRCL) was 50 mL/minute (interquartile range [IQR], 35-65) and higher eTRCL was associated with lower trough concentrations for all antibiotics (P < .05). The median (IQR) trough concentration for meropenem was 12.1 mg/L (7.9-18.8), piperacillin was 78.6 mg/L (49.5-127.3), tazobactam was 9.5 mg/L (6.3-14.2), and vancomycin was 14.3 mg/L (11.6-21.8). Trough concentrations failed to meet optimal higher limits in 26%, 36%, and 72% and optimal lower limits in 4%, 4%, and 55% of patients for meropenem, piperacillin, and vancomycin, respectively. CONCLUSIONS: In critically ill patients treated with RRT, antibiotic dosing regimens, RRT prescription, and eTRCL varied markedly and resulted in highly variable antibiotic concentrations that failed to meet therapeutic targets in many patients.

Extracorporeal Ammonia Clearance for Hyperammonemia in Critically Ill Patients: A Scoping Review.

INTRODUCTION: Hyperammonemia is a life-threatening condition. However, clearance of ammonia via extracorporeal treatment has not been systematically evaluated. METHODS: We searched EMBASE and MEDLINE databases. We included all publications reporting ammonia clearance by extracorporeal treatment in adult and pediatric patients with clearance estimated by direct dialysate ammonia measurement or calculated by formula. Two reviewers screened and extracted data independently. RESULTS: We found 1,770 articles with 312 appropriate for assessment and 28 studies meeting eligibility criteria. Most of the studies were case reports. Hyperammonemia was typically secondary to inborn errors of metabolisms in children and to liver failure in adult patients. Ammonia clearance was most commonly reported during continuous renal replacement therapy (CRRT) and appeared to vary markedly from <5 mL/min/m2 to >250 mL/min/m2. When measured during intermittent hemodialysis (IHD), clearance was highest and correlated with blood flow rate (R2 = 0.853; p < 0.001). When measured during CRRT, ammonia clearance could be substantial and correlated with effluent flow rate (EFR; R2 = 0.584; p < 0.001). Neither correlated with ammonia reduction. Peritoneal dialysis (PD) achieved minimal clearance, and other extracorporeal techniques were rarely studied. CONCLUSIONS: Extracorporeal ammonia clearance varies widely with sometimes implausible values. Treatment modality, blood flow, and EFR, however, appear to affect such clearance with IHD achieving the highest values, PD achieving minimal values, and CRRT achieving substantial values especially at high EFRs. The role of other techniques remains unclear. These findings can help inform practice and future studies.

NephroCheck® Quality Test.

BACKGROUND: The acute kidney injury (AKI) risk score helps detect moderate and severe AKI in the next 12-24 h. However, inappropriate urine collection may impact its results. AIM: The aim of this study was to evaluate the stability of NephroCheck® after urine storage at different temperatures. METHODS: The urine sample was centrifuged and split into 3 tubes. One was tested as soon as possible by the laboratory. The other 2 samples were frozen at -20 and -80°C, and the NephroCheck® test was performed 8 weeks later. RESULTS: The mean values of the AKI risk score were 1.19 ± 0.93, 1.15 ± 1.14, and 1.20 ± 1.11 (ng/mL)2/1,000 for fresh urine, -20, and -80°C, respectively (p = 0.70). Spearman's rank correlation for -20 and -80°C versus immediate processing was strong with a rho of 0.82 and 0.98, respectively. CONCLUSION: The AKI risk score was relatively stable. Urine could be collected without dry ice or liquid nitrogen and kept for up to 8 weeks with either -20 or -80°C freezing with stable NephroCheck® results.

Comparison of the Hemodynamic and Temperature Effects of a 500-mL Bolus of 4% Albumin at Room Versus Body Temperature in Cardiac Surgery Patients.

OBJECTIVE: To compare the hemodynamic effect of room temperature (cold) 4% albumin fluid bolus therapy (FBT) with body temperature (warm) albumin FBT. DESIGN: Prospective, before-after trial. SETTING: A tertiary intensive care unit (ICU). PARTICIPANTS: Sixty ventilated, post-cardiac surgery patients prescribed with 4% albumin FBT. INTERVENTION: Cold or warm 4% albumin 500 ml FBT. MEASUREMENTS AND MAIN RESULTS: We recorded hemodynamic parameters before and for 30 minutes after FBT. Cardiac index (CI) and mean arterial pressure (MAP) responses were defined by a CI increase >15% and a MAP increase >10%, respectively. Immediately after FBT, median [interquartile range] core temperature changed by -0.3 [-0.4; -0.3] °C with cold albumin vs. 0.0 [0.0; 0.1]°C with warm albumin (P<0.001). The median CI increase was 0.3 [0.0; 0.5] L/min/m2 with 14 CI-responders (47%) in both groups (P>0.99). The median immediate MAP increase was 9 [3; 15] mmHg with cold albumin vs. 11 [5; 13] mmHg with warm albumin (P=0.79), with a MAP-response in 16 vs. 17 patients (P=0.99). There was an interaction between group and time for MAP (P=0.002), mean pulmonary artery pressure (PAP) (P=0.002) and core temperature (P<0.001). In the cold albumin group, after the initial response, MAP and mean PAP decreased more slowly than with warm albumin and, after the initial fall, core temperature increased toward baseline. CONCLUSION: In postoperative cardiac surgery patients, warm albumin FBT prevents the decrease in core temperature and, after an initial similar increase, is associated with a faster return of MAP and mean PAP toward baseline.

Prolonged postoperative cerebral oxygen desaturation after cardiac surgery: A prospective observational study.

BACKGROUND: Near-infrared spectroscopy (NIRS) is used routinely to monitor cerebral tissue oxygen saturation (SctO2) during cardiopulmonary bypass (CPB) but is rarely employed outside the operating room. Previous studies indicate that patients are at risk of postoperative cerebral oxygen desaturation after cardiac surgery. OBJECTIVES: We aimed to assess perioperative and postoperative changes in NIRS-derived SctO2 in cardiac surgery patients. DESIGN: Prospective observational study. SETTING: The study was conducted in a tertiary referral university hospital in Australia from December 2017 to December 2018. PATIENTS: We studied 34 adult patients (70.6% men) undergoing cardiac surgery requiring CPB and a reference group of 36 patients undergoing non-cardiac surgical procedures under general anaesthesia. MAIN OUTCOME MEASURES: We measured SctO2 at baseline, during and after surgery, and then once daily until hospital discharge, for a maximum of 7 days. We used multivariate linear mixed-effects modelling to adjust for all relevant imbalances between the two groups. RESULTS: In the cardiac surgery group, SctO2 was 63.7% [95% confidence interval (CI), 62.0 to 65.5] at baseline and 61.0% (95% CI, 59.1 to 62.9, P = 0.01) on arrival in the ICU. From day 2 to day 7 after cardiac surgery, SctO2 progressively declined. At hospital discharge, SctO2 was significantly lower than baseline, at 53.5% (95% CI, 51.8 to 55.2, P < 0.001). In the reference group, postoperative SctO2 was not significantly different from baseline. On multivariable analysis, cardiac surgery, peripheral vascular disease and time since the operation were associated with greater cerebral desaturation, whereas higher haemoglobin concentrations were associated with slightly better cerebral oxygenation. CONCLUSION: After cardiac surgery on CPB, but not after non-cardiac surgery, most patients experience prolonged cerebral desaturation. Such postoperative desaturation remained unresolved 7 days after surgery. The underlying mechanisms and time to resolution of such cerebral desaturations require further investigation.

Normative values for SedLine-based processed electroencephalography parameters in awake volunteers: a prospective observational study.

Processed electroencephalography (pEEG) is used to monitor depth of anaesthesia and/or sedation. A novel device (SedLine®) has been recently introduced into clinical practice. However, there are no published data on baseline SedLine values for awake adult subjects. We aimed to determine baseline values for SedLine-derived parameters in eyes-open and eyes-closed states. We performed a prospective observational study in healthy volunteers. SedLine EEG-derived parameters were recorded for 2 min with eyes closed and 8 min with eyes open. We determined the overall reference range for each value, as well as the reference range in each phase. We investigated changes in recorded parameters between the two phases, and the interaction between EMG, baseline characteristics, and Patient State Index (PSI). We collected data from 50 healthy volunteers, aged 23-63 years. Median PSI was 94 (92-95) with eyes open and 88 (87-91) with eyes closed (p < 0.001 for open versus close). EMG activity decreased from 47.2% (46.6-47.9) with eyes open to 28.6% (28.0-29.3) with eyes closing (p < 0.001). There was a significant positive correlation between EMG and PSI with eyes closed (p = 0.01) but not with eyes open, which was confirmed with linear regression analysis (p = 0.01). In awake volunteers, keeping eyes open induces significant changes to SedLine-derived parameters, most likely due to increased EMG activity (e.g. eye blinking). These findings have implications for the clinical interpretation of PSI parameters and for the planning of future research.

Optimal ventilator settings after return of spontaneous circulation.

PURPOSE OF REVIEW: To describe current practice, recent advances in knowledge and future directions for research related to the post return of spontaneous circulation (ROSC) ventilatory management of cardiac arrest patients. RECENT FINDINGS: Out-of-hospital cardiac arrest (OHCA) is a major public health problem with an estimated incidence of approximately one per 1000 persons per year. A priority of intensive care management of resuscitated OHCA patients is to reduce secondary reperfusion injury. Most OHCA patients are mechanically ventilated. Most of these require mechanical ventilation as they are unconscious and for oxygen (O2) management and carbon dioxide (CO2) control. Low levels of O2 and CO2 following OHCA is associated with poor outcome. Recently, very high fraction of inspired oxygen has been associated with poor outcomes and elevated CO2 levels have been associated with improved neurological outcomes. Moreover, it is increasingly being appreciated that the ventilator may be a tool to adjust physiological parameters to enhance the chances of favourable outcomes. Finally, ventilator settings themselves and the adoption of protective ventilation strategies may affect lung-brain interactions and are being explored as other avenues for therapeutic benefit. SUMMARY: Current evidence supports the targeting of normal arterial O2 and CO2 tensions during mechanical ventilation following ROSC after cardiac arrest. Use of protective lung strategies during mechanical ventilation in resuscitated cardiac arrest patients is advocated. The potential therapeutic benefits of conservative O2 therapy, mild hypercapnia and the optimal ventilator settings to use post-ROSC period will be confirmed or refuted in clinical trials.

The effect of dexmedetomidine on vasopressor requirements in patients with septic shock: a subgroup analysis of the Sedation Practice in Intensive Care Evaluation [SPICE III] Trial.

BACKGROUND: Septic shock is associated with decreased vasopressor responsiveness. Experimental data suggest that central alpha2-agonists like dexmedetomidine (DEX) increase vasopressor responsiveness and reduce catecholamine requirements in septic shock. However, DEX may also cause hypotension and bradycardia. Thus, it remains unclear whether DEX is hemodynamically safe or helpful in this setting. METHODS: In this post hoc subgroup analysis of the Sedation Practice in Intensive Care Evaluation (SPICE III) trial, an international randomized trial comparing early sedation with dexmedetomidine to usual care in critically patients receiving mechanical ventilation, we studied patients with septic shock admitted to two tertiary ICUs in Australia and Switzerland. The primary outcome was vasopressor requirements in the first 48 h after randomization, expressed as noradrenaline equivalent dose (NEq [µg/kg/min] = noradrenaline + adrenaline + vasopressin/0.4). RESULTS: Between November 2013 and February 2018, 417 patients were recruited into the SPICE III trial at both sites. Eighty-three patients with septic shock were included in this subgroup analysis. Of these, 44 (53%) received DEX and 39 (47%) usual care. Vasopressor requirements in the first 48 h were similar between the two groups. Median NEq dose was 0.03 [0.01, 0.07] µg/kg/min in the DEX group and 0.04 [0.01, 0.16] µg/kg/min in the usual care group (p = 0.17). However, patients in the DEX group had a lower NEq/MAP ratio, indicating lower vasopressor requirements to maintain the target MAP. Moreover, on adjusted multivariable analysis, higher dexmedetomidine dose was associated with a lower NEq/MAP ratio. CONCLUSIONS: In critically ill patients with septic shock, patients in the DEX group received similar vasopressor doses in the first 48 h compared to the usual care group. On multivariable adjusted analysis, dexmedetomidine appeared to be associated with lower vasopressor requirements to maintain the target MAP. TRIAL REGISTRATION: The SPICE III trial was registered at ClinicalTrials.gov ( NCT01728558 ).

Point-of-care creatinine measurements to predict acute kidney injury.

BACKGROUND: Plasma creatinine (Cr) is a marker of kidney function and typically measured once daily. We hypothesized that Cr measured by point-of-care technology early after ICU admission would be a good predictor of acute kidney injury (AKI) the next day in critically ill patients. METHODS: We conducted a retrospective database audit in a single tertiary ICU database. We included patients with normal first admission Cr (CrF ) and identified a Cr value (CrP ) obtained within 6-12 hours from ICU admission. We used their difference converted into percentage (delta-Cr-%) to predict subsequent AKI (based on Cr and/or need for renal replacement therapy) the next day. We assessed predictive value by calculating area under the receiver characteristic curve (AUC), logistic regression models for AKI with and without delta-Cr-%, and the category-free net reclassifying index (cfNRI). RESULTS: We studied 780 patients. Overall, 70 (9.0%) fulfilled the Cr AKI definition by CrP measurement. On day 2, 148 patients (19.0%) were diagnosed with AKI. AUC (95% CI) for delta-Cr-% to predict AKI on day 2 was 0.82 (95% CI 0.78-0.86), and 0.74 (95% CI 0.69-0.80) when patients with AKI based on the CrP were excluded. Using a cut-off of 17% increment, the positive likelihood ratio (95% CI) for delta-Cr-% to predict AKI was 3.5 (2.9-4.2). The cfNRI was 90.0 (74.9-106.1). CONCLUSIONS: Among patients admitted with normal Cr, early changes in Cr help predict AKI the following day.

A Pilot, Double-Blind, Randomized, Controlled Trial of High-Dose Intravenous Vitamin C for Vasoplegia After Cardiac Surgery.

OBJECTIVE: To conduct a pilot feasibility and physiologic efficacy study of high-dose vitamin C in patients with vasoplegia after cardiac surgery. DESIGN: Prospective, double-blind, randomized, controlled trial. SETTING: Two tertiary intensive care units (ICUs). PARTICIPANTS: Post-cardiac surgery patients with vasoplegia. INTERVENTIONS: The authors randomly assigned the patients to receive either high-dose intravenous vitamin C (1,500 mg every 6 hours) or placebo. The primary outcome was time from randomization to resolution of vasoplegia. Secondary outcomes included total norepinephrine equivalent dose in the first 2 days, ICU length of stay, ICU mortality, and in-hospital mortality. MEASUREMENTS AND MAIN RESULTS: The authors studied 50 patients (25 patients in each arms). The mean (standard deviation) time to resolution of vasoplegia was 27.0 (16.5) hours in the vitamin C group versus 34.7 (41.1) hours in the placebo group (mean decrease with vitamin C of 7.7 hours, 95% confidence interval -10.5 to 25.9, p = 0.40). The median (interquartile range) norepinephrine equivalent dose in the first 2 days was 64.9 (23.5-236.5) µg/kg versus 47.4 (21.4-265.9) µg/kg in the vitamin C and placebo group (p = 0.75). The median duration of ICU admission was similar (1.4 [0.5-2.5] days and 1.5 [0.5-3.3] days in the vitamin C and placebo group; p = 0.36). Only 1 patient, in the vitamin C arm, died. CONCLUSION: In patients with post-cardiac surgery vasoplegia, high-dose vitamin C infusion was feasible, appeared safe, and, within the limitations of a pilot study, did not achieve statistically faster resolution of vasoplegia.

Continuous Magnesium Infusion to Prevent Atrial Fibrillation After Cardiac Surgery: A Sequential Matched Case-Controlled Pilot Study.

OBJECTIVE: The authors aimed to test whether a bolus of magnesium followed by continuous intravenous infusion might prevent the development of atrial fibrillation (AF) after cardiac surgery. DESIGN: Sequential, matched, case-controlled pilot study. SETTING: Tertiary university hospital. PARTICIPANTS: Matched cohort of 99 patients before and intervention cohort of 99 consecutive patients after the introduction of a continuous magnesium infusion protocol. INTERVENTIONS: The magnesium infusion protocol consisted of a 10 mmol loading dose of magnesium sulphate followed by a continuous infusion of 3 mmol/h over a maximum duration of 96 hours or until intensive care unit discharge. MEASUREMENTS AND MAIN RESULTS: The study groups were balanced except for a lower cardiac index in the intervention cohort. The mean duration of magnesium infusion was 27.93 hours (95% confidence interval [CI]: 24.10-31.76 hours). The intervention group had greater serum peak magnesium levels: 1.72 mmol/L ± 0.34 on day 1, 1.32 ± 0.36 on day 2 versus 1.01 ± 1.14 and 0.97 ± 0.13, respectively, in the control group (p < 0.01). Atrial fibrillation occurred in 25 patients (25.3%) in the intervention group and 40 patients (40.4%) in the control group (odds ratio 0.49, 95% CI, 0.27-0.92; p = 0.023). On a multivariate Cox proportional hazards model, the hazard ratio for the development of AF was significantly less in the intervention group (hazard ratio 0.45, 95% CI, 0.26-0.77; p = 0.004). CONCLUSION: The magnesium delivery strategy was associated with a decreased incidence of postoperative AF in cardiac surgery patients. These findings provide a rationale and preliminary data for the design of future randomized controlled trials.