Resumption of Cardiac Activity after Withdrawal of Life-Sustaining Measures.

BACKGROUND: The minimum duration of pulselessness required before organ donation after circulatory determination of death has not been well studied. METHODS: We conducted a prospective observational study of the incidence and timing of resumption of cardiac electrical and pulsatile activity in adults who died after planned withdrawal of life-sustaining measures in 20 intensive care units in three countries. Patients were intended to be monitored for 30 minutes after determination of death. Clinicians at the bedside reported resumption of cardiac activity prospectively. Continuous blood-pressure and electrocardiographic (ECG) waveforms were recorded and reviewed retrospectively to confirm bedside observations and to determine whether there were additional instances of resumption of cardiac activity. RESULTS: A total of 1999 patients were screened, and 631 were included in the study. Clinically reported resumption of cardiac activity, respiratory movement, or both that was confirmed by waveform analysis occurred in 5 patients (1%). Retrospective analysis of ECG and blood-pressure waveforms from 480 patients identified 67 instances (14%) with resumption of cardiac activity after a period of pulselessness, including the 5 reported by bedside clinicians. The longest duration after pulselessness before resumption of cardiac activity was 4 minutes 20 seconds. The last QRS complex coincided with the last arterial pulse in 19% of the patients. CONCLUSIONS: After withdrawal of life-sustaining measures, transient resumption of at least one cycle of cardiac activity after pulselessness occurred in 14% of patients according to retrospective analysis of waveforms; only 1% of such resumptions were identified at the bedside. These events occurred within 4 minutes 20 seconds after a period of pulselessness. (Funded by the Canadian Institutes for Health Research and others.).

Should New Data on Rehabilitation Interventions in Critically Ill Patients Change Clinical Practice? Updated Meta-Analysis of Randomized Controlled Trials.

OBJECTIVES: We published a meta-analysis in March 2020 to assess the impact of rehabilitation in the ICU on clinical outcomes. Since then, 15 new randomized controlled trials (RCTs) have been published; we updated the meta-analysis to show how the recent studies have tipped the scale. DESIGN: Systematic review and meta-analysis. SETTING: An update of secondary data analysis of RCTs published between January 1998 and July 2023 performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PATIENTS: Critically ill adults. INTERVENTIONS: Cycling exercises or neuromuscular electrical stimulation (NMES) or protocolized physical rehabilitation (PPR) or functional electrical stimulation-assisted cycle ergometry (FESCE) compared with standard of care. MEASUREMENTS AND MAIN RESULTS: Days on a mechanical ventilator, length of stay in ICU and at the hospital, and mortality. We found 15 RCTs (one on cycling, eight on NMES alone, four on PPR, and two on FESCE) into which 2116 patients were randomized. The updated meta-analysis encompasses a total of 5664 patients. The exercise interventions did not influence mortality (odds ratio, 1.00 [0.87-1.14]; n = 53 RCTs) but reduced the duration of mechanical ventilation (mean difference, -1.76 d [-2.8 to -0.8 d]; n = 46) and length of stay in ICU (-1.16 d [-2.3 to 0.0 d]; n = 45). The effects on the length of mechanical ventilation and ICU stay were only significant for the PPR subgroup by a median of -1.7 days (95% CI, -3.2 to -0.2 d) and -1.9 days (95% CI, -3.5 to -0.2 d), respectively. Notably, newly published trials provided consistent results and reduced the overall heterogeneity of these results. CONCLUSIONS: None of the rehabilitation intervention strategies being studied influence mortality. Both mechanical ventilation and ICU stay were shortened by PPR, this strengthens the earlier findings as all new RCTs yielded very consistent results. However, no early rehabilitation interventions in passive patients seem to have clinical benefits. Regarding long-term functional outcomes, the results remain inconclusive.

Assessment of Faecal Microbiota Transplant Stability in Deep-Freeze Conditions: A 12-Month Ex Vivo Viability Analysis.

BACKGROUND: Faecal microbiota transplantation (FMT) is an established treatment for Clostridioides difficile infection and is under investigation for other conditions. The availability of suitable donors and the logistics of fresh stool preparation present challenges, making frozen, biobanked stools an attractive alternative. AIMS: This study aimed to evaluate the long-term viability of bacterial populations in faecal samples stored at -80°C for up to 12 months, supporting the feasibility of using frozen grafts for FMT. METHODS: Fifteen faecal samples from nine healthy donors were processed, mixed with cryoprotectants and stored at -80°C. Samples were assessed at baseline and after 3, 6 and 12 months using quantitative culturing methods to determine the concentration of live bacteria. RESULTS: Quantitative analysis showed no significant decrease in bacterial viability over the 12-month period for both aerobic and anaerobic cultures (p = 0.09). At all timepoints, the coefficients of variability in colony-forming unit (CFU) counts were greater between samples (102 ± 21% and 100 ± 13% for aerobic and anaerobic cultures, respectively) than the variability between measurements of the same sample (30 ± 22% and 30 ± 19%). CONCLUSIONS: The study confirmed that faecal microbiota can be preserved with high viability in deep-freeze storage for up to a year, making allogenic FMT from biobanked samples a viable and safer option for patients. However, a multidonor approach may be beneficial to mitigate the risk of viability loss in any single donor sample.

Amiodarone but not propafenone impairs bioenergetics and autophagy of human myocardial cells.

Cardiac and extra-cardiac side effects of common antiarrhythmic agents might be related to drug-induced mitochondrial dysfunction. Supratherapeutic doses of amiodarone have been shown to impair mitochondria in animal studies, whilst influence of propafenone on cellular bioenergetics is unknown. We aimed to assess effects of protracted exposure to pharmacologically relevant doses of amiodarone and propafenone on cellular bioenergetics and mitochondrial biology of human and mouse cardiomyocytes. In this study, HL-1 mouse atrial cardiomyocytes and primary human cardiomyocytes derived from the ventricles of the adult heart were exposed to 2 and 7 µg/mL of either amiodarone or propafenone. After 24 h, extracellular flux analysis and confocal laser scanning microscopy were used to measure mitochondrial functions. Autophagy was assessed by western blots and live-cell imaging of lysosomes. In human cardiomyocytes, amiodarone significantly reduced mitochondrial membrane potential and ATP production, in association with an inhibition of fatty acid oxidation and impaired complex I- and II-linked respiration in the electron transport chain. Expectedly, this led to increased anaerobic glycolysis. Amiodarone increased the production of reactive oxygen species and autophagy was also markedly affected. In contrast, propafenone-exposed cardiomyocytes did not exert any impairment of cellular bioenergetics. Similar changes after amiodarone treatment were observed during identical experiments performed on HL-1 mouse cardiomyocytes, suggesting a comparable pharmacodynamics of amiodarone among mammalian species. In conclusion, amiodarone but not propafenone in near-therapeutic concentrations causes a pattern of mitochondrial dysfunction with affected autophagy and metabolic switch from oxidative metabolism to anaerobic glycolysis in human cardiomyocytes.

Functional electrical stimulation-assisted cycle ergometry-based progressive mobility programme for mechanically ventilated patients: randomised controlled trial with 6 months follow-up.

PURPOSE: Functional electrical stimulation-assisted cycle ergometry (FESCE) enables in-bed leg exercise independently of patients' volition. We hypothesised that early use of FESCE-based progressive mobility programme improves physical function in survivors of critical care after 6 months. METHODS: We enrolled mechanically ventilated adults estimated to need >7 days of intensive care unit (ICU) stay into an assessor-blinded single centre randomised controlled trial to receive either FESCE-based protocolised or standard rehabilitation that continued up to day 28 or ICU discharge. RESULTS: We randomised in 1:1 ratio 150 patients (age 61±15 years, Acute Physiology and Chronic Health Evaluation II 21±7) at a median of 21 (IQR 19-43) hours after admission to ICU. Mean rehabilitation duration of rehabilitation delivered to intervention versus control group was 82 (IQR 66-97) versus 53 (IQR 50-57) min per treatment day, p<0.001. At 6 months 42 (56%) and 46 (61%) patients in interventional and control groups, respectively, were alive and available to follow-up (81.5% of prespecified sample size). Their Physical Component Summary of SF-36 (primary outcome) was not different at 6 months (50 (IQR 21-69) vs 49 (IQR 26-77); p=0.26). At ICU discharge, there were no differences in the ICU length of stay, functional performance, rectus femoris cross-sectional diameter or muscle power despite the daily nitrogen balance was being 0.6 (95% CI 0.2 to 1.0; p=0.004) gN/m2 less negative in the intervention group. CONCLUSION: Early delivery of FESCE-based protocolised rehabilitation to ICU patients does not improve physical functioning at 6 months in survivors. TRIAL REGISTRATION NUMBER: NCT02864745.

Effects of Rehabilitation Interventions on Clinical Outcomes in Critically Ill Patients: Systematic Review and Meta-Analysis of Randomized Controlled Trials.

OBJECTIVES: To assess the impact of rehabilitation in ICU on clinical outcomes. DATA SOURCES: Secondary data analysis of randomized controlled trials published between 1998 and October 2019 was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. STUDY SELECTION: We have selected trials investigating neuromuscular electrical stimulation or cycling exercises or protocolized physical rehabilitation as compared to standard of care in critically ill adults. DATA EXTRACTION: Mortality, length of stay in ICU and at hospital, days on mechanical ventilator, and adverse events. DATA SYNTHESIS: We found 43 randomized controlled trials (nine on cycling, 14 on neuromuscular electrical stimulation alone and 20 on protocolized physical rehabilitation) into which 3,548 patients were randomized and none of whom experienced an intervention-related serious adverse event. The exercise interventions had no influence on mortality (odds ratio 0.94 [0.79-1.12], n = 38 randomized controlled trials) but reduced duration of mechanical ventilation (mean difference, -1.7 d [-2.5 to -0.8 d], n = 32, length of stay in ICU (-1.2 d [-2.5 to 0.0 d], n = 32) but not at hospital (-1.6 [-4.3 to 1.2 d], n = 23). The effects on the length of mechanical ventilation and ICU stay were only significant for the protocolized physical rehabilitation subgroup and enhanced in patients with longer ICU stay and lower Acute Physiology and Chronic Health Evaluation II scores. There was no benefit of early start of the intervention. It is likely that the dose of rehabilitation delivered was much lower than dictated by the protocol in many randomized controlled trials and negative results may reflect the failure to implement the intervention. CONCLUSIONS: Rehabilitation interventions in critically ill patients do not influence mortality and are safe. Protocolized physical rehabilitation significantly shortens time spent on mechanical ventilation and in ICU, but this does not consistently translate into long-term functional benefit. Stable patients with lower Acute Physiology and Chronic Health Evaluation II at admission (<20) and prone to protracted ICU stay may benefit most from rehabilitation interventions.

Recommendations for core critical care ultrasound competencies as a part of specialist training in multidisciplinary intensive care: a framework proposed by the European Society of Intensive Care Medicine (ESICM).

Critical care ultrasound (CCUS) is an essential component of intensive care practice. Although existing international guidelines have focused on training principles and determining competency in CCUS, few countries have managed to operationalize this guidance into an accessible, well-structured programme for clinicians training in multidisciplinary intensive care. We seek to update and reaffirm appropriate CCUS scope so that it may be integrated into the international Competency-based Training in Intensive Care Medicine. The resulting recommendations offer the most contemporary and evolved set of core CCUS competencies for an intensive care clinician yet described. Importantly, we discuss the rationale for inclusion but also exclusion of competencies listed. BACKGROUND/AIM: Critical care ultrasound (CCUS) is an essential component of intensive care practice. The purpose of this consensus document is to determine those CCUS competencies that should be a mandatory part of training in multidisciplinary intensive care. METHODS: A three-round Delphi method followed by face-to-face meeting among 32 CCUS experts nominated by the European Society of Intensive Care Medicine. Agreement of at least 90% of experts was needed in order to enlist a competency as mandatory. RESULTS: The final list of competencies includes 15 echocardiographic, 5 thoracic, 4 abdominal, deep vein thrombosis diagnosis and central venous access aid. CONCLUSION: The resulting recommendations offer the most contemporary and evolved set of core CCUS competencies for an intensive care clinician yet described.

Critical Care Ultrasound: A Systematic Review of International Training Competencies and Program.

OBJECTIVES: Critical care ultrasonography has become established within ICUs as a diagnostic tool and to guide management strategies and practical procedures. Following an international consensus statement in 2011, various national professional societies and organizations have sought to develop and deliver training program. The aim of this review was to assess the similarities and differences among these postgraduate intensive care/critical care training program. DATA SOURCES: A systematic review was performed in two steps. First, we searched medical databases and national societies' websites for documents meeting predefined inclusion criteria. If not found, professionals related to critical care ultrasonography were contacted. DATA EXTRACTION: Data were extracted independently by two authors. Analyses were conducted on general training requirements as well as specific competencies defined in the documents. DATA SYNTHESIS: Eight national program from seven countries were identified from a total of 25 countries; all identified program have defined competencies for core critical care ultrasonography. Although there were common themes across these program, significant variations in training requirements and assessments existed, for example, number of scans required for echocardiography training ranged from 10 to 100. Furthermore, the specifics of each ultrasound module varied between program. CONCLUSIONS: Despite widespread and increasing use of ultrasound in ICUs, the majority of countries lacked a formal training program and clearly defined competencies. Even among the countries where these are available, there remains variability. There is a need to better define the competencies required in core critical care ultrasonography and standardize the assessment process.

Diagnosing acute acid-base disorders.

Traditional diagnostic approach to acute acid-base disorders is based on the assessment of bicarbonate buffer system, in which pH is determined by the ratio of [HCO3-] to pCO2. This, in turn, creates basis for distinguishing metabolic and respiratory disorders, and defines the term “compensation”. The use of electroneutrality advantageously complements the bicarbonate-based approach when dealing with complex acid-base disorders. It is possible to simplify this approach so it can be applied only using mental arithmetics. In principle, the space created by strong ion difference (which can be simplified to [Na+]-[Cl-]) is shared by negative charges on albumin and bicarbonate. In turn, a shrinkage of this space ([Na+]-[Cl-]  36 mM causes alka-losis, as well as a decrease in albumin concentration (for every 10 g/L of albumin, 3 mM is freed to be occupied by [HCO3-]). Lastly, if the sum of negative charges on albumin and [HCO3-] is lower than estimated strong ion difference, an unmeasured anion must be present. This concept is explained on commented case reports.

Effects of Propofol on Cellular Bioenergetics in Human Skeletal Muscle Cells.

OBJECTIVES: Propofol may adversely affect the function of mitochondria and the clinical features of propofol infusion syndrome suggest that this may be linked to propofol-related bioenergetic failure. We aimed to assess the effect of therapeutic propofol concentrations on energy metabolism in human skeletal muscle cells. DESIGN: In vitro study on human skeletal muscle cells. SETTINGS: University research laboratories. SUBJECTS: Patients undergoing hip surgery and healthy volunteers. INTERVENTIONS: Vastus lateralis biopsies were processed to obtain cultured myotubes, which were exposed to a range of 1-10 µg/mL propofol for 96 hours. MEASUREMENTS AND MAIN RESULTS: Extracellular flux analysis was used to measure global mitochondrial functional indices, glycolysis, fatty acid oxidation, and the functional capacities of individual complexes of electron transfer chain. In addition, we used [1-C]palmitate to measure fatty acid oxidation and spectrophotometry to assess activities of individual electron transfer chain complexes II-IV. Although cell survival and basal oxygen consumption rate were only affected by 10 µg/mL of propofol, concentrations as low as 1 µg/mL reduced spare electron transfer chain capacity. Uncoupling effects of propofol were mild, and not dependent on concentration. There was no inhibition of any respiratory complexes with low dose propofol, but we found a profound inhibition of fatty acid oxidation. Addition of extra fatty acids into the media counteracted the propofol effects on electron transfer chain, suggesting inhibition of fatty acid oxidation as the causative mechanism of reduced spare electron transfer chain capacity. Whether these metabolic in vitro changes are observable in other organs and at the whole-body level remains to be investigated. CONCLUSIONS: Concentrations of propofol seen in plasma of sedated patients in ICU cause a significant inhibition of fatty acid oxidation in human skeletal muscle cells and reduce spare capacity of electron transfer chain in mitochondria.

Propofol infusion syndrome: a structured review of experimental studies and 153 published case reports.

INTRODUCTION: Propofol infusion syndrome (PRIS) is a rare, but potentially lethal adverse effect of a commonly used drug. We aimed to review and correlate experimental and clinical data about this syndrome. METHODS: We searched for all case reports published between 1990 and 2014 and for all experimental studies on PRIS pathophysiology. We analysed the relationship between signs of PRIS and the rate and duration of propofol infusion causing PRIS. By multivariate logistic regression we looked at the risk factors for mortality. RESULTS: Knowledge about PRIS keeps evolving. Compared to earlier case reports in the literature, recently published cases describe older patients developing PRIS at lower doses of propofol, in whom arrhythmia, hypertriglyceridaemia and fever are less frequently seen, with survival more likely. We found that propofol infusion rate and duration, the presence of traumatic brain injury and fever are factors independently associated with mortality in reported cases of PRIS (area under receiver operator curve = 0.85). Similar patterns of exposure to propofol (in terms of time and concentration) are reported in clinical cases and experimental models of PRIS. Cardiac failure and metabolic acidosis occur early in a dose-dependent manner, while arrhythmia, other electrocardiographic changes and rhabdomyolysis appear more frequently after prolonged propofol infusions, irrespective of dose. CONCLUSION: PRIS can develop with propofol infusion <4 mg/kg per hour and its diagnosis may be challenging as some of its typical features (hypertriglyceridaemia, fever, hepatomegaly, heart failure) are often (>95 %) missing and others (arrhythmia, electrocardiographic changes) occur late.

Mitochondrial function in skeletal muscle of patients with protracted critical illness and ICU-acquired weakness.

BACKGROUND: Mitochondrial damage occurs in the acute phase of critical illness, followed by activation of mitochondrial biogenesis in survivors. It has been hypothesized that bioenergetics failure of skeletal muscle may contribute to the development of ICU-acquired weakness. The aim of the present study was to determine whether mitochondrial dysfunction persists until protracted phase of critical illness. METHODS: In this single-centre controlled-cohort ex vivo proof-of-concept pilot study, we obtained vastus lateralis biopsies from ventilated patients with ICU-acquired weakness (n = 8) and from age and sex-matched metabolically healthy controls (n = 8). Mitochondrial functional indices were measured in cytosolic context by high-resolution respirometry in tissue homogenates, activities of respiratory complexes by spectrophotometry and individual functional capacities were correlated with concentrations of electron transport chain key subunits from respiratory complexes II, III, IV and V measured by western blot. RESULTS: The ability of aerobic ATP synthesis (OXPHOS) was reduced to ~54% in ICU patients (p<0.01), in correlation with the depletion of complexes III (~38% of control, p = 0.02) and IV (~26% of controls, p<0.01) and without signs of mitochondrial uncoupling. When mitochondrial functional indices were adjusted to citrate synthase activity, OXPHOS and the activity of complexes I and IV were not different, whilst the activities of complexes II and III were increased in ICU patients 3-fold (p<0.01) respectively 2-fold (p<0.01). CONCLUSIONS: Compared to healthy controls, in ICU patients we have demonstrated a ~50% reduction of the ability of skeletal muscle to synthetize ATP in mitochondria. We found a depletion of complex III and IV concentrations and relative increases in functional capacities of complex II and glycerol-3-phosphate dehydrogenase/complex III.

ß-hydroxybutyrate exposure restores mitochondrial function in skeletal muscle satellite cells of critically ill patients.

BACKGROUND & AIM: Dysfunction of skeletal muscle satellite cells might impair muscle regeneration and prolong ICU-acquired weakness, a condition associated with disability and delayed death. This study aimed to elucidate the distinct metabolic effects of critical illness and ß-OH-butyrate on satellite cells isolated from these patients. METHODS: Satellite cells were extracted from vastus lateralis muscle biopsies of patients with ICU-acquired weakness (n = 10) and control group of healthy volunteers or patients undergoing elective hip replacement surgery (n = 10). The cells were exposed to standard culture media supplemented with ß-OH-butyrate to assess its influence on cell proliferation by ELISA, mitochondrial functions by extracellular flux analysis, electron transport chain complexes by high resolution respirometry, and ROS production by confocal microscopy. RESULTS: Critical illness led to a decline in maximal respiratory capacity, ATP production and glycolytic capacity and increased ROS production in ICU patients' cells. Notably, the function of complex II was impaired due to critical illness but restored to normal levels upon exposure to ß-OH-butyrate. While ß-OH-butyrate significantly reduced ROS production in both control and ICU groups, it had no significant impact on global mitochondrial functions. CONCLUSION: Critical illness induces measurable bioenergetic dysfunction of skeletal muscle satellite cells. ß-OH-butyrate displayed a potential in rectifying complex II dysfunction caused by critical illness and this warrants further exploration.

Efficiency of two-member crews in delivering prehospital advanced life support cardiopulmonary resuscitation: A scoping review.

Background: Advanced Life Support (ALS) during cardiopulmonary resuscitation (CPR) for out-of-hospital cardiac arrest (OHCA) is frequently administered by two-member crews. However, ALS CPR is mostly designed for larger crews, and the feasibility and efficacy of implementing ALS guidelines for only two rescuers remain unclear. Objective: This scoping review aims to examine the existing evidence and identify knowledge gaps in the efficiency of pre-hospital ALS CPR performed by two-member teams. Design: A comprehensive search was undertaken across the following databases: PubMed, Web of Science, SCOPUS, Cochrane Library Trials, and ClinicalTrials.gov. The search covered publications in English or German from January 1, 2005, to November 30, 2023. The review included studies that focused on ALS CPR procedures carried out by two-member teams in adult patients in either simulated or clinical settings. Results: A total of 22 articles were included in the qualitative synthesis. Seven topics in two-person prehospital ALS/CPR delivery were identified: 1) effect of team configuration on clinical outcome and CPR quality, 2) early airway management and ventilation techniques, 3) mechanical chest compressions, 4) prefilled syringes, 5) additional equipment, 6) adaptation of recommended ALS/CPR protocols, and 7) human factors. Conclusion: There is a lack of comprehensive data regarding the adaptation of the recommended ALS algorithm in CPR for two-member crews. Although simulation studies indicate potential benefits arising from the employment of mechanical chest compression devices, prefilled syringes, and automation-assisted protocols, the current evidence is too limited to support specific modifications to existing guidelines.

The outcomes of patients with septic shock treated with propafenone compared to amiodarone for supraventricular arrhythmias are related to end-systolic left atrial volume.

AIMS: A recently published trial has shown no differences in outcomes between patients with new-onset supraventricular arrhythmia (SVA) in septic shock treated with either propafenone or amiodarone. However, these outcome data have not been evaluated in relation to the presence or absence of a dilated left atrium (LA). METHODS AND RESULTS: Patients with SVA and a left ventricular ejection fraction ≥ 35% were randomized to receive intravenous propafenone (70 mg bolus followed by 400-840 mg/24 h) or amiodarone (300 mg bolus followed by 600-1800 mg/24 h). They were divided into groups based on whether their end-systolic left atrial volume (LAVI) was ≥40 mL/m². The subgroup outcomes assessed were survival at ICU discharge, 1 month, 3 months, 6 months, and 12 months. Propafenone cardioverted earlier (P = 0.009) and with fewer recurrences (P = 0.001) in the patients without LA enlargement (n = 133). Patients with LAVI < 40 mL/m2 demonstrated a mortality benefit of propafenone over the follow-up of 1 year [Cox regression, hazard ratio (HR) 0.6 (95% CI 0.4; 0.9), P = 0.014]. Patients with dilated LA (n = 37) achieved rhythm control earlier in amiodarone (P = 0.05) with similar rates of recurrences (P = 0.5) compared to propafenone. The outcomes for patients with LAVI ≥ 40 mL/m2 were less favourable with propafenone compared to amiodarone at 1 month [HR 3.6 (95% CI 1.03; 12.5), P = 0.045]; however, it did not reach statistical significance at 1 year [HR 1.9 (95% CI 0.8; 4.4), P = 0.138]. CONCLUSION: Patients with non-dilated LA who achieved rhythm control with propafenone in the setting of septic shock had better short-term and long-term outcomes than those treated with amiodarone, which seemed to be more effective in patients with LAVI ≥ 40 mL/m². TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03029169, registered on 24 January 2017.

Quantifying pH-induced changes in plasma strong ion difference during experimental acidosis: clinical implications for base excess interpretation.

It is commonly assumed that changes in plasma strong ion difference (SID) result in equal changes in whole blood base excess (BE). However, at varying pH, albumin ionic-binding and transerythrocyte shifts alter the SID of plasma without affecting that of whole blood (SIDwb), i.e., the BE. We hypothesize that, during acidosis, 1) an expected plasma SID (SIDexp) reflecting electrolytes redistribution can be predicted from albumin and hemoglobin's charges, and 2) only deviations in SID from SIDexp reflect changes in SIDwb, and therefore, BE. We equilibrated whole blood of 18 healthy subjects (albumin = 4.8 ± 0.2 g/dL, hemoglobin = 14.2 ± 0.9 g/dL), 18 septic patients with hypoalbuminemia and anemia (albumin = 3.1 ± 0.5 g/dL, hemoglobin = 10.4 ± 0.8 g/dL), and 10 healthy subjects after in vitro-induced isolated anemia (albumin = 5.0 ± 0.2 g/dL, hemoglobin = 7.0 ± 0.9 g/dL) with varying CO2 concentrations (2-20%). Plasma SID increased by 12.7 ± 2.1, 9.3 ± 1.7, and 7.8 ± 1.6 mEq/L, respectively (P < 0.01) and its agreement (bias[limits of agreement]) with SIDexp was strong: 0.5[-1.9; 2.8], 0.9[-0.9; 2.6], and 0.3[-1.4; 2.1] mEq/L, respectively. Separately, we added 7.5 or 15 mEq/L of lactic or hydrochloric acid to whole blood of 10 healthy subjects obtaining BE of -6.6 ± 1.7, -13.4 ± 2.2, -6.8 ± 1.8, and -13.6 ± 2.1 mEq/L, respectively. The agreement between ΔBE and ΔSID was weak (2.6[-1.1; 6.3] mEq/L), worsening with varying CO2 (2-20%): 6.3[-2.7; 15.2] mEq/L. Conversely, ΔSIDwb (the deviation of SID from SIDexp) agreed strongly with ΔBE at both constant and varying CO2: -0.1[-2.0; 1.7], and -0.5[-2.4; 1.5] mEq/L, respectively. We conclude that BE reflects only changes in plasma SID that are not expected from electrolytes redistribution, the latter being predictable from albumin and hemoglobin's charges.NEW & NOTEWORTHY This paper challenges the assumed equivalence between changes in plasma strong ion difference (SID) and whole blood base excess (BE) during in vitro acidosis. We highlight that redistribution of strong ions, in the form of albumin ionic-binding and transerythrocyte shifts, alters SID without affecting BE. We demonstrate that these expected SID alterations are predictable from albumin and hemoglobin's charges, or from the noncarbonic whole blood buffer value, allowing a better interpretation of SID and BE during in vitro acidosis.

Mechanism of paracetamol-induced hypotension in critically ill patients: a prospective observational cross-over study.

OBJECTIVE: To elucidate the mechanism of hypotension following intravenous administration of paracetamol (acetaminophen) to patients on the Intensive Care Unit. DESIGN: Prospective observational cross-over study. SETTING: Intensive Care Unit, University Hospital Královské Vinohrady, Prague, Czech Republic. METHODS: Ventilated critically ill patients monitored by PiCCO and administered intravenous paracetamol at the same time were eligible for the study. We recorded haemodynamic indices, as well as core and peripheral temperatures, continuously for 3 h after the dose of paracetamol. Ranitidine was then used as a control drug known not to influence haemodynamics. RESULTS: We included 6 subjects, and recorded 48 cycles of observations after administration of paracetamol, and 35 cycles after administration of the control drug. Haemodynamic parameters were not different at the baseline and administration of control drug did not result in any change in haemodynamics. After intravenous paracetamol, mean arterial pressure (MAP) dropped by 7% (p<0.001) with a nadir at the 19th minute. In 22 measurement cycles (45%) we noted >15% reduction in MAP with paracetamol. Analysis of these cycles suggests that hypotension with paracetamol can be caused by reduction of both cardiac index and systemic vascular resistance. In febrile cycles paracetamol caused narrowing of the gradient between central and peripheral temperatures suggesting skin vasodilation. These changes were not correlated to a change of systemic vascular resistance at any time point. CONCLUSION: Hypotension with intravenous paracetamol in critically ill patients is caused by a reduction of both cardiac output and systemic vascular resistance. We did not demonstrate any relation between haemodynamic changes and antipyretic action of paracetamol. A possibility that cardiac output is reduced with paracetamol might be clinically important.

Mitragyna speciosa (Kratom) poisoning: Findings from ten cases.

Kratom is a mixture of compounds that are present in the leaves of the tropical tree Mitragyna speciosa. It is used as a psychoactive agent with both opiate and stimulant-like effects. In this case series we describe the signs, symptoms, and the management of kratom overdose in the prehospital setting and in intensive care. We retrospectively searched for cases in the Czech Republic. Over 36 months we found 10 cases of kratom poisoning, which healthcare records were analyzed and reported as per CARE guidelines. The dominant symptoms in our series were neurological and included quantitative (n = 9) or qualitative (n = 4) disorder of consciousness. Signs and symptoms of vegetative instability [hypertension (n = 3) and tachycardia (n = 3) vs. bradycardia/cardiac arrest (n = 2), mydriasis (n = 2) vs. miosis (n = 3)] were noticed. Prompt response to naloxone in two cases and lack of response in one patient were observed. All patients survived and the effect of intoxication wore off within two days. Kratom overdose toxidrome is variable and, in keeping with its receptor physiology, consists of signs and symptoms of opioid-like overdose, sympathetic overactivation and serotonin-like syndrome. Naloxone can help to avoid intubation in some cases.

Machine learning determination of motivators of terminal extubation during the transition to end-of-life care in intensive care unit.

Procedural aspects of compassionate care such as the terminal extubation are understudied. We used machine learning methods to determine factors associated with the decision to extubate the critically ill patient at the end of life, and whether the terminal extubation shortens the dying process. We performed a secondary data analysis of a large, prospective, multicentre, cohort study, death prediction and physiology after removal of therapy (DePPaRT), which collected baseline data as well as ECG, pulse oximeter and arterial waveforms from WLST until 30 min after death. We analysed a priori defined factors associated with the decision to perform terminal extubation in WLST using the random forest method and logistic regression. Cox regression was used to analyse the effect of terminal extubation on time from WLST to death. A total of 616 patients were included into the analysis, out of which 396 (64.3%) were terminally extubated. The study centre, low or no vasopressor support, and good respiratory function were factors significantly associated with the decision to extubate. Unadjusted time to death did not differ between patients with and without extubation (median survival time extubated vs. not extubated: 60 [95% CI: 46; 76] vs. 58 [95% CI: 45; 75] min). In contrast, after adjustment for confounders, time to death of extubated patients was significantly shorter (49 [95% CI: 40; 62] vs. 85 [95% CI: 61; 115] min). The decision to terminally extubate is associated with specific centres and less respiratory and/or vasopressor support. In this context, terminal extubation was associated with a shorter time to death.