Induced normothermia ameliorates the procoagulant host response in human endotoxaemia

Background Dysregulation of coagulation occurs commonly in sepsis, ranging from mild coagulopathy with decreased platelets to disseminated intravascular coagulation (DIC). We investigated the effect of induced normothermia on coagulation during lipopolysaccharide (LPS)-induced endotoxaemia in healthy volunteers. Methods Twelve volunteers received an infusion of bacterial lipopolysaccharide (Escherichia coli; 2 ng kg−1) and were assigned to either induced normothermia or control. Induced normothermia to maintain core temperature at 37°C consisted of external surface cooling, cold i.v. fluids, and medication to reduce shivering (buspirone, clonidine, and magnesium sulphate). The primary outcome was the DIC score (International Society on Thrombosis and Haemostasis guideline). Prothrombin time (PT), activated partial thromboplastin time (aPTT), D-dimer, plasma von Willebrand factor (vWf), and rotational thromboelastometry (ROTEM) were measured before and 1, 3, 6, and 8 h after LPS infusion. Differences between groups were tested with a mixed effects model. Results In control subjects, lipopolysaccharide caused a fever, transiently decreased platelet levels and lowered activated partial thromboplastin time, while prolonging prothrombin time and increasing D-Dimer and vWf levels. Normothermia prevented the DIC-score exceeding 4, which occurred in 50% of control subjects. Normothermia also reduced the fall in platelet count by 67x109 L−1([95%CI:27-107]; p=0.002), aPTT (mean difference:3s [95%CI:1-5]; p=0.005) and lowered vWf levels by 89% ([95%CI:6-172]; p=0.03), compared to the fever group. ROTEM measurements were unaffected by lipopolysaccharide. Conclusion In human endotoxaemia, induced normothermia decreases markers of endothelial activation and DIC. Maintaining normothermia may reduce coagulopathy in hyperinflammatory states

The Influence of Carbon Dioxide on Cerebral Autoregulation during Sevoflurane-based Anesthesia in Patients with Type 2 Diabetes

Background: Cerebral autoregulation (CA) continuously adjusts cerebrovascular resistance to maintain cerebral blood flow (CBF) constant despite changes in blood pressure. Also, CBF is proportional to changes in arterial carbon dioxide (CO2) (cerebrovascular CO2reactivity). Hypercapnia elicits cerebral vasodilation that attenuates CA efficacy, while hypocapnia produces cerebral vasoconstriction that enhances CA efficacy. In this study, we quantified the influence of sevoflurane anesthesia on CO2reactivity and the CA-CO2relationship. Methods: We studied patients with type 2 diabetes mellitus (DM), prone to cerebrovascular disease, and compared them to control subjects. In 33 patients (19 DM, 14 control), end-tidal CO2, blood pressure, and CBF velocity were monitored awake and during sevoflurane-based anesthesia. CA, calculated with transfer function analysis assessing phase lead (degrees) between low-frequency oscillations in CBF velocity and mean arterial blood pressure, was quantified during hypocapnia, normocapnia, and hypercapnia. Results: In both control and DM patients, awake CO2reactivity was smaller (2.8%/mm Hg CO2) than during sevoflurane anesthesia (3.9%/mm Hg; P<0.005). Hyperventilation increased CA efficacy more (3 deg./mm Hg CO2) in controls than in DM patients (1.8 deg./mm Hg CO2; P<0.001) in both awake and sevoflurane-anesthetized states. Conclusions: The CA-CO2relationship is impaired in awake patients with type 2 DM. Sevoflurane-based anesthesia does not further impair this relationship. In patients with DM, hypocapnia induces cerebral vasoconstriction, but CA efficacy does not improve as observed in healthy subjects

The effect of proactive versus reactive treatment of hypotension on postoperative disability and outcome in surgical patients under anaesthesia (PRETREAT): clinical trial protocol and considerations

Background: Intraoperative hypotension has been extensively studied for its association with adverse outcomes. However, small sample sizes and methodological issues limit the causal inference that can be drawn. Methods: In this multicentre, adaptive, randomised controlled trial, we will include 5000 adult inpatients scheduled for elective non-cardiac surgery under general or central neuraxial anaesthesia. Patients will be either randomly allocated to the intervention or care-as-usual group using computer-generated blocks of four, six, or eight, with an allocation ratio of 1:1. In the intervention arm patients will be divided into low-, intermediate-, and high-risk groups based on their likelihood to experience intraoperative hypotension, with resulting mean blood pressure targets of 70, 80, and 90 mm Hg, respectively. Anaesthesia teams will be provided with a clinical guideline on how to keep patients at their target blood pressure. During the first 6 months of the trial the intervention strategy will be evaluated and further revised in adaptation cycles of 3 weeks if necessary, to improve successful impact on the clinical process. The primary outcome is postoperative disability after 6 months measured with the World Health Organization Disability Assessment Score (WHODAS) 2.0 questionnaire. Ethics and dissemination: This study protocol has been approved by the Medical Ethics Committee of the University Medical Centre Utrecht (20–749) and all protocol amendments will be communicated to the Medical Ethics Committee. The study protocol is in adherence with the Declaration of Helsinki and the guideline of Good Clinical Practice. Dissemination plans include publication in a peer-reviewed journal. Clinical trial registration: The Dutch Trial Register, NL9391. Registered on 22 March 2021