Effect of Daytime versus Nighttime on Prehospital Care and Outcomes after Severe Traumatic Brain Injury.

Background/Objectives: Severe traumatic brain injury (TBI) is a frequent cause of morbidity and mortality worldwide. In the Netherlands, suspected TBI is a criterion for the dispatch of the physician-staffed helicopter emergency medical services (HEMS) which are operational 24 h per day. It is unknown if patient outcome is influenced by the time of day during which the incident occurs. Therefore, we investigated the association between the time of day of the prehospital treatment of severe TBI and 30-day mortality. Methods: A retrospective analysis of prospectively collected data from the BRAIN-PROTECT study was performed. Patients with severe TBI treated by one of the four Dutch helicopter emergency medical services were included and followed up to one year. The association between prehospital treatment during day- versus nighttime, according to the universal daylight period, and 30-day mortality was analyzed with multivariable logistic regression. A planned subgroup analysis was performed in patients with TBI with or without any other injury. Results: A total of 1794 patients were included in the analysis, of which 1142 (63.7%) were categorized as daytime and 652 (36.3%) as nighttime. Univariable analysis showed a lower 30-day mortality in patients with severe TBI treated during nighttime (OR 0.74, 95% CI 0.60-0.91, p = 0.004); this association was no longer present in the multivariable model (OR 0.82, 95% CI 0.59-1.16, p = 0.262). In a subgroup analysis, no association was found between mortality rates and the time of prehospital treatment in patients with combined injuries (TBI and any other injury). Patients with isolated TBI had a lower mortality rate when treated during nighttime than when treated during daytime (OR 0.51, 95% CI 0.34-0.76, p = 0.001). Within the whole cohort, daytime versus nighttime treatments were not associated with differences in functional outcome defined by the Glasgow Outcome Scale. Conclusions: In the overall study population, no difference was found in 30-day mortality between patients with severe TBI treated during day or night in the multivariable model. Patients with isolated severe TBI had lower mortality rates at 30 days when treated at nighttime.

Effectiveness of tranexamic acid in burn patients undergoing surgery - a systematic review and meta-analysis.

BACKGROUND: Reducing blood loss during excisional surgery in burn patients remains a challenge. Tranexamic acid during surgery can potentially reduce blood loss. The use of tranexamic acid during excisional surgery in burn patients has recently been described in a review and meta-analysis. However, quality assessment on studies included was not performed and this review did not apply independent reviewers. Quality assessment of studies investigating the effectiveness of tranexamic acid in burn patients is crucial before concusions can be drawn. Therefore, we conducted a systematic review and meta-analysis of the literature investigating the effectiveness of tranexamic acid in burn patients undergoing surgery. METHODS: A systematic review and meta-analysis of the literature was conducted. The study was pre-registered in PROSPERO database (CRD42023396183). RESULTS: Five studies including two randomised controlled trials (RCTs) with a total of 303 patients were included. Risk of bias of the included studies was moderate to high. Individual results of the studies were heterogeneous. In three studies of moderate quality the administration of tranexamic acid resulted in a reduction of blood loss per unit excised area, accounting as moderate level of evidence. In two low-quality studies and one moderate quality study the administration of tranexamic acid resulted in a reduction of transfused packed Red Blood Cells (pRBC's), accounting for moderate level of evidence. Postoperative haemoglobin levels were higher after tranexamic acid administration in one study, accounting for insufficient evidence. Meta-analysis pooling overall blood loss from two separate RCTs failed to detect a statistically significant reduction. Substantial heterogeneity was observed. CONCLUSIONS: Moderate level of evidence indicates that tranexamic acid reduces blood loss per unit of excised area and transfusion of packed Red Blood Cells. Results indicate that tranexamic acid can be beneficial in burn patients undergoing surgery. More high-quality research is needed to confirm these results. Future studies should focus on the dosing of tranexamic acid, the administration approaches, and even consider combining these approaches. TRIAL REGISTRATION: PROSPERO: CRD42023396183.

Optimization of cardiopulmonary bypass prime fluid to preserve microcirculatory perfusion during on-pump coronary artery bypass graft surgery: PRIME study protocol for a double-blind randomized trial.

BACKGROUND: Acute microcirculatory perfusion disturbances and organ edema are important factors leading to organ dysfunction during cardiac surgery with cardiopulmonary bypass (CPB). Priming of the CPB system with crystalloid or colloid fluids, which inevitably leads to hemodilution, could contribute to this effect. However, there is yet no optimal evidence-based strategy for this type of priming. Hence, we will investigate different priming strategies to reduce hemodilution and preserve microcirculatory perfusion. METHODS: The PRIME study is a single-center double-blind randomized trial. Patients undergoing elective coronary artery bypass graft surgery with CPB will be randomized into three groups of prime fluid strategy: (1) gelofusine with crystalloid, (2) albumin with crystalloid, or (3) crystalloid and retrograde autologous priming. We aim to include 30 patients, 10 patients in each arm. The primary outcome is the change in microcirculatory perfusion. Secondary outcomes include colloid oncotic pressure; albumin; hematocrit; electrolytes; fluid balance and requirements; transfusion rates; and endothelial-, glycocalyx-, inflammatory- and renal injury markers. Sublingual microcirculatory perfusion will be measured using non-invasive sidestream dark field video microscopy. Microcirculatory and blood measurements will be performed at five consecutive time points during surgery up to 24 h after admission to the intensive care unit. DISCUSSION: PRIME is the first study to assess the effect of different prime fluid strategies on microcirculatory perfusion in cardiac surgery with CPB. If the results suggest that a specific crystalloid or colloid prime fluid strategy better preserves microcirculatory perfusion during on-pump cardiac surgery, the current study may help to find the optimal pump priming in cardiac surgery. TRIAL REGISTRATION: ClinicalTrials.gov NCT05647057. Registered on 04/25/2023. CLINICALTRIALS: gov PRS: Record Summary NCT05647057, all items can be found in the protocol.

Physical Activity Levels, Correlates, and All-Cause Mortality Risk in People Living With Different Health Conditions.

BACKGROUND: To better understand physical activity behavior and its health benefits in people living with health conditions, we studied people with and without 20 different self-reported health conditions with regard to (1) their physical activity levels, (2) factors correlated with these physical activity levels, and (3) the association between physical activity and all-cause mortality. METHODS: We used a subsample (n = 88,659) of the Lifelines cohort study from the Netherlands. For people living with and without 20 different self-reported health conditions, we studied the aforementioned factors in relation to physical activity. Physical activity was assessed with the Short Questionnaire to Assess Health-Enhancing Physical Activity Questionnaire, and mortality data were obtained from the Dutch death register. RESULTS: People with a reported health condition were less likely to meet physical activity guidelines than people without a reported health condition (odds ratios ranging from 0.55 to 0.89). Higher body mass index and sitting time, and lower self-rated health, physical functioning, and education levels were associated with lower odds of meeting physical activity guidelines across most health conditions. Finally, we found a protective association between physical activity and all-cause mortality in both people living with and without different health conditions. CONCLUSION: People living with different health conditions are generally less physically active compared with people living without a health condition. Both people living with and without self-reported health conditions share a number of key factors associated with physical activity levels. We also observed the expected protective association between physical activity and all-cause mortality.

Etomidate versus Ketamine as Prehospital Induction Agent in Patients with Suspected Severe Traumatic Brain Injury.

BACKGROUND: Severe traumatic brain injury is a leading cause of morbidity and mortality among young people around the world. Prehospital care focuses on the prevention and treatment of secondary brain injury and commonly includes tracheal intubation after induction of general anesthesia. The choice of induction agent in this setting is controversial. This study therefore investigated the association between the chosen induction medication etomidate versus S(+)-ketamine and the 30-day mortality in patients with severe traumatic brain injury who received prehospital airway management in the Netherlands. METHODS: This study is a retrospective analysis of the prospectively collected observational data of the Brain Injury: Prehospital Registry of Outcomes, Treatments and Epidemiology of Cerebral Trauma (BRAIN-PROTECT) cohort study. Patients with suspected severe traumatic brain injury who were transported to a participating trauma center and who received etomidate or S(+)-ketamine for prehospital induction of anesthesia for advanced airway management were included. Statistical analyses were performed with multivariable logistic regression and inverse probability of treatment weighting analysis. RESULTS: In total, 1,457 patients were eligible for analysis. No significant association between the administered induction medication and 30-day mortality was observed in unadjusted analyses (32.9% mortality for etomidate versus 33.8% mortality for S(+)-ketamine; P = 0.716; odds ratio, 1.04; 95% CI, 0.83 to 1.32; P = 0.711), as well as after adjustment for potential confounders (odds ratio, 1.08; 95% CI, 0.67 to 1.73; P = 0.765; and risk difference 0.017; 95% CI, -0.051 to 0.084; P = 0.686). Likewise, in planned subgroup analyses for patients with confirmed traumatic brain injury and patients with isolated traumatic brain injury, no significant differences were found. Consistent results were found after multiple imputations of missing data. CONCLUSIONS: The analysis found no evidence for an association between the use of etomidate or S(+)-ketamine as an anesthetic agent for intubation in patients with traumatic brain injury and mortality after 30 days in the prehospital setting, suggesting that the choice of induction agent may not influence the patient mortality rate in this population.

Association between prehospital end-tidal carbon dioxide levels and mortality in patients with suspected severe traumatic brain injury.

PURPOSE: Severe traumatic brain injury is a leading cause of mortality and morbidity, and these patients are frequently intubated in the prehospital setting. Cerebral perfusion and intracranial pressure are influenced by the arterial partial pressure of CO2 and derangements might induce further brain damage. We investigated which lower and upper limits of prehospital end-tidal CO2 levels are associated with increased mortality in patients with severe traumatic brain injury. METHODS: The BRAIN-PROTECT study is an observational multicenter study. Patients with severe traumatic brain injury, treated by Dutch Helicopter Emergency Medical Services between February 2012 and December 2017, were included. Follow-up continued for 1 year after inclusion. End-tidal CO2 levels were measured during prehospital care and their association with 30-day mortality was analyzed with multivariable logistic regression. RESULTS: A total of 1776 patients were eligible for analysis. An L-shaped association between end-tidal CO2 levels and 30-day mortality was observed (p = 0.01), with a sharp increase in mortality with values below 35 mmHg. End-tidal CO2 values between 35 and 45 mmHg were associated with better survival rates compared to < 35 mmHg. No association between hypercapnia and mortality was observed. The odds ratio for the association between hypocapnia (< 35 mmHg) and mortality was 1.89 (95% CI 1.53-2.34, p < 0.001) and for hypercapnia (≥ 45 mmHg) 0.83 (0.62-1.11, p = 0.212). CONCLUSION: A safe zone of 35-45 mmHg for end-tidal CO2 guidance seems reasonable during prehospital care. Particularly, end-tidal partial pressures of less than 35 mmHg were associated with a significantly increased mortality.

Prehospital Intubation of Patients with Severe Traumatic Brain Injury: A Dutch Nationwide Trauma Registry Analysis.

OBJECTIVE: Patients with severe traumatic brain injury (TBI) are commonly intubated during prehospital treatment despite a lack of evidence that this is beneficial. Accumulating evidence even suggests that prehospital intubation may be hazardous, in particular when performed by inexperienced EMS clinicians. To expand the limited knowledge base, we studied the relationship between prehospital intubation and hospital mortality in patients with severe TBI in a large Dutch trauma database. We specifically hypothesized that the relationship differs depending on whether a physician-based emergency medical service (EMS) was involved in the treatment, as opposed to intubation by paramedics. METHODS: A retrospective analysis was performed using the Dutch Nationwide Trauma Registry that includes all trauma patients in the Netherlands who are admitted to any hospital with an emergency department. All patients treated for severe TBI (Head Abbreviated Injury Scale score ≥4) between January 2015 and December 2019 were selected. Multivariable logistic regression was used to assess the relationship between prehospital intubation and mortality while adjusting for potential confounders. An interaction term between prehospital intubation and the involvement of physician-based EMS was added to the model. Complete case analysis as well as multiple imputation were performed. RESULTS: 8946 patients (62% male, median age 63 years) were analyzed. The hospital mortality was 26.4%. Overall, a relationship between prehospital intubation and higher mortality was observed (complete case: OR 1.86, 95% CI 1.35-2.57, p < 0.001; multiple imputation: OR 1.92, 95% CI 1.56-2.36, p < 0.001). Adding the interaction revealed that the relationship of prehospital intubation may depend on whether physician-based EMS is involved in the treatment (complete case: p = 0.044; multiple imputation: p = 0.062). Physician-based EMS involvement attenuated but did not completely remove the detrimental association between prehospital intubation and mortality. CONCLUSION: The data do not support the common practice of prehospital intubation. The effect of prehospital intubation on mortality might depend on EMS clinician experience, and it seems prudent to involve prehospital personnel well proficient in prehospital intubation whenever intubation is potentially required. The decision to perform prehospital intubation should not merely be based on the largely unsupported dogma that it is generally needed in severe TBI, but should rather individually weigh potential benefits and harms.

Smartwatch based automatic detection of out-of-hospital cardiac arrest: Study rationale and protocol of the HEART-SAFE project.

Out-of-hospital cardiac arrest (OHCA) is a leading cause of mortality. Immediate detection and treatment are of paramount importance for survival and good quality of life. The first link in the 'chain of survival' after OHCA - the early recognition and alerting of emergency medical services - is at the same time the weakest link as it entirely depends on witnesses. About one half of OHCA cases are unwitnessed, and victims of unwitnessed OHCA have virtually no chance of survival with good neurologic outcome. Also in case of a witnessed cardiac arrest, alerting of emergency medical services is often delayed for several minutes. Therefore, a technological solution to automatically detect cardiac arrests and to instantly trigger an emergency response has the potential to save thousands of lives per year and to greatly improve neurologic recovery and quality of life in survivors. The HEART-SAFE consortium, consisting of two academic centres and three companies in the Netherlands, collaborates to develop and implement a technical solution to reliably detect OHCA based on sensor signals derived from commercially available smartwatches using artificial intelligence. In this manuscript, we describe the rationale, the envisioned solution, as well as a protocol outline of the work packages involved in the development of the technology.

Rivastigmine for ECT-induced cognitive adverse effects in late life depression (RECALL study): A multicenter, randomized, double blind, placebo-controlled, cross-over trial in patients with depression aged 55 years or older: Rationale, objectives and methods.

Background: Cognitive side-effects are an important reason for the limited use of electroconvulsive therapy (ECT). Cognitive side-effects are heterogeneous and occur frequently in older persons. To date, insight into these side-effects is hampered due to inconsistencies in study designs and small sample sizes. Among all cognitive side-effects, confusion and delirious states are especially troublesome for patients, relatives and clinicians. In particular inter-ictal delirium-like states are worrisome, since they may lead to premature treatment discontinuation. Besides a need for further insight into determinants of cognitive side-effects of ECT, there is a great need for treatment options. Methods and design: The Rivastigmine for ECT-induced Cognitive Adverse effects in Late Life depression (RECALL) study combines a multicenter, prospective cohort study on older patients with depression, treated with ECT, with an embedded randomized, placebo-controlled cross-over trial to examine the effect of rivastigmine on inter-ictal delirium. Patients are recruited in four centers across the Netherlands and Belgium. We aim to include 150 patients into the cohort study, in order to be able to subsequently include 30 patients into the trial. Patients are included in the trial when inter-ictal delirium, assessed by the Confusion Assessment method (CAM), or a drop in Mini Mental State Examination (MMSE) score of ≥4 during ECT, develops. In the cohort study, comprehensive measurements of ECT-related cognitive side-effects-and their putative determinants-are done at baseline and during the ECT-course. The primary outcome of the clinical trial is the effectiveness of rivastigmine on inter-ictal delirium-severity, assessed with a change in the Delirium Rating Scale-Revised-98. Secondary outcomes of the clinical trial are several ECT-characteristics and side-effects of rivastigmine. Discussion: This study is the first clinical trial with a focus on ECT-induced, inter-ictal delirium. The cohort provides the basis for recruitment of patients for the cross-over trial and additionally provides an excellent opportunity to unravel cognitive side-effects of ECT and identify putative determinants. This paper describes the rationale and study protocol. Clinical trial registration: EudraCT 2014-003385-24.

Evaluation of electronic screening in the preoperative process.

STUDY OBJECTIVE: Rising patient numbers, with increasing complexity, challenge the sustainability of the current preoperative process. We evaluated whether an electronic screening application can distinguish patients that need a preoperative consultation from low-risk patients that can be first seen on the day of surgery. DESIGN: Prospective cohort study. SETTING: Preoperative clinic of a tertiary academic hospital. PATIENTS: 1395 adult patients scheduled for surgery or procedural sedation. INTERVENTIONS: We assessed a novel electronic preoperative screening application which consists of a questionnaire with a maximum of 185 questions regarding the patient's medical history and current state of health. The application provides an extensive health report, including an American Society of Anesthesiologists physical status (ASA-PS) classification and a recommendation for either consultation by an anesthesiologist at the preoperative clinic or approval for screening on the day of surgery. MEASUREMENTS: The recommendation of the electronic screening system was compared with the regular preoperative assessment using measures of diagnostic accuracy and agreement. Secondary outcomes included ASA-PS classification, patient satisfaction, and the anesthesiologists' opinion on the completeness and quality of the screening report. RESULTS: Sensitivity to detect patients who needed additional consultation was 97.5% (95%CI 91.2-99.7) and the negative likelihood ratio was 0.08 (95%CI 0.02-0.32). 407 (29.2%) patients were approved for surgery by both electronic screening and anesthesiologist. In 909 (65.2%) cases, the electronic screening system recommended further consultation while the anesthesiologist approved the patient (specificity 30.9% (95%CI 28.4-33.5); poor level of agreement (ĸ = 0.04)). Agreement regarding ASA-PS classification scores was weak (ĸ = 0.48). The majority of patients (78.0%) felt positive about electronic screening replacing the regular preoperative assessment. CONCLUSIONS: Electronic screening can reliably identify patients who can have their first contact with an anesthesiologist on the day of surgery, potentially allowing a major proportion of patients to safely bypass the preoperative clinic.

Antifibrinolytics in the treatment of traumatic brain injury.

PURPOSE OF REVIEW: Traumatic brain injury (TBI) is a leading cause of trauma-related deaths, and pharmacologic interventions to limit intracranial bleeding should improve outcomes. Tranexamic acid reduces mortality in injured patients with major systemic bleeding, but the effects of antifibrinolytic drugs on outcomes after TBI are less clear. We therefore summarize recent evidence to guide clinicians on when (not) to use antifibrinolytic drugs in TBI patients. RECENT FINDINGS: Tranexamic acid is the only antifibrinolytic drug that has been studied in patients with TBI. Several recent studies failed to conclusively demonstrate a benefit on survival or neurologic outcome. A large trial with more than 12 000 patients found no significant effect of tranexamic acid on head-injury related death, all-cause mortality or disability across the overall study population, but observed benefit in patients with mild to moderate TBI. Observational evidence signals potential harm in patients with isolated severe TBI. SUMMARY: Given that the effect of tranexamic acid likely depends on a variety of factors, it is unlikely that a 'one size fits all' approach of administering antifibrinolytics to all patients will be helpful. Tranexamic acid should be strongly considered in patients with mild to moderate TBI and should be avoided in isolated severe TBI.

External Validation of the ACTA-PORT Transfusion Risk Score in Older Cardiac Surgery Patients at Risk of Frailty.

OBJECTIVES: Accurate preoperative transfusion risk stratification may serve to better manage older patients undergoing cardiac surgery. Therefore, the aim of the present study was to externally validate the existing Association of Cardiothoracic Anesthetists perioperative risk of blood transfusion (ACTA-PORT) score in a population ≥70 years of age scheduled for cardiac surgery. Furthermore, the study authors investigated the additional prognostic value of individual frailty variables to this transfusion risk score. DESIGN: A retrospective analysis. SETTING: At a tertiary-care hospital. PARTICIPANTS: Five hundred seven patients aged ≥70 years undergoing elective cardiac surgery from July 2015 to August 2017. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the administration of a perioperative blood transfusion. Frailty domains were assessed in a preanesthesia geriatric assessment, and a priori selection of biomarkers derived from blood was determined. The original ACTA-PORT score resulted in a c-statistic of 0.78 (95% confidence interval 0.74-0.82), with moderate calibration in predicting perioperative allogeneic transfusion in older patients undergoing cardiac surgery. Model updating, using the closed testing procedure, resulted in model revision with a higher discriminatory performance (c-statistic of 0.83, 95% confidence interval 0.79-0.86) and corrected calibration slope. Iron deficiency, impaired nutritional status, and physical impairment were associated with perioperative transfusions. The addition of individual frailty variables to the updated ACTA-PORT model did not result in improved predictive performance. CONCLUSIONS: External validation of the original ACTA-PORT score showed good discrimination and moderate calibration in older patients at risk of frailty undergoing cardiac surgery. Updating the original ACTA-PORT improved the predictive performance. Careful evaluation of additional frailty domains did not add prognostic value to the ACTA-PORT score.

Incidence, Clinical Characteristics and Outcomes of Early Hyperbilirubinemia in Critically Ill Patients: Insights From the MARS Study.

OBJECTIVE: To investigate the incidence, clinical characteristics and outcomes of early hyperbilirubinemia in critically ill patients. DESIGN AND SETTING: This is a post hoc analysis of a prospective multicenter cohort study. PATIENTS: Patients with measured bilirubin levels within the first 2 days after ICU admission were eligible. Patients with liver cirrhosis were excluded. ENDPOINTS: The primary endpoint was the incidence of early hyperbilirubinemia, defined as bilirubin ≥33 µmol/L within 2 days after ICU admission. Secondary endpoints included clinical characteristics of patients with versus patients without early hyperbilirubinemia, and outcomes up to day 30. RESULTS: Of 4,836 patients, 559 (11.6%) patients had early hyperbilirubinemia. Compared to patients without early hyperbilirubinemia, patients with early hyperbilirubinemia presented with higher severity of illness scores, and higher incidences of sepsis and organ failure. After adjustment for confounding variables, early hyperbilirubinemia remained associated with mortality at day 30 (odds ratio, 1.31 [95%-confidence interval 1.06-1.60]; P = 0.018). Patients with early hyperbilirubinemia and thrombocytopenia (interaction P-value = 0.005) had a higher likelihood of death within 30 days (odds ratio, 2.61 [95%-confidence interval 2.08-3.27]; P < 0.001) than patients with early hyperbilirubinemia and a normal platelet count (odds ratio, 1.09 [95%-confidence interval 0.75-1.55]; P = 0.655). CONCLUSIONS: Early hyperbilirubinemia occurs frequently in the critically ill, and these patients present with higher disease severity and more often with sepsis and organ failures. Early hyperbilirubinemia has an association with mortality, albeit this association was only found in patients with concomitant thrombocytopenia.

Dexmedetomidine Clearance Decreases with Increasing Drug Exposure: Implications for Current Dosing Regimens and Target-controlled Infusion Models Assuming Linear Pharmacokinetics.

BACKGROUND: Numerous pharmacokinetic models have been published aiming at more accurate and safer dosing of dexmedetomidine. The vast majority of the developed models underpredict the measured plasma concentrations with respect to the target concentration, especially at plasma concentrations higher than those used in the original studies. The aim of this article was to develop a dexmedetomidine pharmacokinetic model in healthy adults emphasizing linear versus nonlinear kinetics. METHODS: The data of two previously published clinical trials with stepwise increasing dexmedetomidine target-controlled infusion were pooled to build a pharmacokinetic model using the NONMEM software package (ICON Development Solutions, USA). Data from 48 healthy subjects, included in a stratified manner, were utilized to build the model. RESULTS: A three-compartment mamillary model with nonlinear elimination from the central compartment was superior to a model assuming linear pharmacokinetics. Covariates included in the final model were age, sex, and total body weight. Cardiac output did not explain between-subject or within-subject variability in dexmedetomidine clearance. The results of a simulation study based on the final model showed that at concentrations up to 2 ng · ml-1, the predicted dexmedetomidine plasma concentrations were similar between the currently available Hannivoort model assuming linear pharmacokinetics and the nonlinear model developed in this study. At higher simulated plasma concentrations, exposure increased nonlinearly with target concentration due to the decreasing dexmedetomidine clearance with increasing plasma concentrations. Simulations also show that currently approved dosing regimens in the intensive care unit may potentially lead to higher-than-expected dexmedetomidine plasma concentrations. CONCLUSIONS: This study developed a nonlinear three-compartment pharmacokinetic model that accurately described dexmedetomidine plasma concentrations. Dexmedetomidine may be safely administered up to target-controlled infusion targets under 2 ng · ml-1 using the Hannivoort model, which assumed linear pharmacokinetics. Consideration should be taken during long-term administration and during an initial loading dose when following the dosing strategies of the current guidelines.

Breathing variability-implications for anaesthesiology and intensive care.

The respiratory system reacts instantaneously to intrinsic and extrinsic inputs. This adaptability results in significant fluctuations in breathing parameters, such as respiratory rate, tidal volume, and inspiratory flow profiles. Breathing variability is influenced by several conditions, including sleep, various pulmonary diseases, hypoxia, and anxiety disorders. Recent studies have suggested that weaning failure during mechanical ventilation may be predicted by low respiratory variability. This review describes methods for quantifying breathing variability, summarises the conditions and comorbidities that affect breathing variability, and discusses the potential implications of breathing variability for anaesthesia and intensive care.

Association of Plasma Fibrinogen and Thromboelastography With Blood Loss in Complex Cardiac Surgery.

Postoperative coagulopathic bleeding is common in cardiac surgery and is associated with increased morbidity and mortality. Ideally, real-time information on in-vivo coagulation should be available. However, up to now it is unclear which perioperative coagulation parameters can be used best to accurately identify patients at increased risk of bleeding. The present study analyzed the associations of perioperative fibrinogen concentrations and whole blood viscoelastic tests with postoperative bleeding in 89 patients undergoing combined cardiac surgery procedures. Postoperative bleeding was recorded until 24 hours after surgery. Regression analyses were performed to establish associations between blood loss and coagulation parameters after cardiopulmonary bypass including a prediction model with known confounding factors for bleeding. Coagulation tests show large changes over the perioperative course with the strongest coagulopathic deviations from baseline after cardiopulmonary bypass. After adjustment for multiple confounders, viscoelastic clot strength instead of fibrinogen concentration showed a similar performance for 24 hour blood loss and a better performance for 6 hour blood loss. This makes intraoperative viscoelastic testing a useful tool to strengthen early clinical decision-making with the potential to reduce perioperative blood transfusions.

Cell salvage in burn excisional surgery.

BACKGROUND: Hemostasis during burn surgery is difficult to achieve, and high blood loss commonly occurs. Bleeding control measures are limited, and many patients require allogeneic blood transfusions. Cell salvage is a well-known method used to reduce transfusions. However, its evidence in burns is limited. Therefore, this study aimed to examine the feasibility of cell salvage during burn surgery. STUDY DESIGN AND METHODS: A prospective, observational study was conducted with 16 patients (20 measurements) scheduled for major burn surgery. Blood was recovered by washing saturated gauze pads with heparinized saline, which was then processed using the Cell Saver. Erythrocyte concentrate quality was analyzed by measuring hemoglobin, hematocrit, potassium, and free hemoglobin concentration. Microbial contamination was assessed based on cultures at every step of the process. Differences in blood samples were tested using the Student's t-test. RESULTS: The red blood cell mass recovered was 29 ± 11% of the mass lost. Patients' preoperative hemoglobin and hematocrit levels were 10.5 ± 1.8 g/dL and 0.33 ± 0.05 L/L, respectively. The erythrocyte concentrate showed hemoglobin and hematocrit levels of 13.2 ± 3.9 g/dL and 0.40 ± 0.11 L/L thus showing a concentration effect. The potassium level was lower in the erythrocyte concentrate (2.5 ± 1.5 vs. 4.1 ± 0.4 mmol/L, p < 0.05). The free hemoglobin level was low (0.16 ± 0.21 µmol/L). All cultures of the erythrocyte concentrate showed bacterial growth compared to 21% of wound cultures. CONCLUSION: Recovering erythrocytes during burn excisional surgery using cell salvage is possible. Despite strict sterile handling, erythrocyte concentrates of all patients showed bacterial contamination. The consequence of this contamination remains unclear and should be investigated in future studies.