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Critically ill patients are frequently at risk of neurological dysfunction as a result of primary neurological conditions or secondary insults. Determining which aspects of brain function are affected and how best to manage the neurological dysfunction can often be difficult and is complicated by the limited information that can be gained from clinical examination in such patients and the effects of therapies, notably sedation, on neurological function. Methods to measure and monitor brain function have evolved considerably in recent years and now play an important role in the evaluation and management of patients with brain injury. Importantly, no single technique is ideal for all patients and different variables will need to be monitored in different patients; in many patients, a combination of monitoring techniques will be needed. Although clinical studies support the physiologic feasibility and biologic plausibility of management based on information from various monitors, data supporting this concept from randomized trials are still required.

info:eu-repo/semantics/published

Injury and activation of somatic afferent nerve fibers may alter critical oxygen delivery (DO2C), the point at which oxygen consumption becomes dependent upon delivery, and hence reduce tolerance to hypovolemia. The present study investigated the mechanism of this. Anesthetized mongrel dogs were divided into two groups: control (n = 6) and those subject to brachial nerve stimulation (BNS; n = 5). Whole body oxygen delivery (DO2I) and consumption were initially similar in both groups. DO2I was reduced by cardiac tamponade to determine DO2C. DO2C was significantly higher in BNS compared with control (11.5: 11.0-16.7 vs. 7.5: 6.9-9.5 ml.min-1.kg-1; median: Q1 - Q3), whereas critical oxygen extraction ratios were lower (54.8: 39.7-61.2 vs. 78.3: 53.5-92.4%). At approximately DO2C, normalized femoral blood flow was lower than renal flow in control (renal-femoral difference 17.4: 8.7-40.0%) but not in BNS (-7.8: -14.8 to +11.8%). These results indicate that activation of somatic afferent nerve fibers elevates DO2C. This could be due to an impairment in peripheral oxygen extraction as a consequence of a redistribution of blood flow away from metabolically active vital organs toward relatively inactive skeletal muscle.

Prehospital intra-arrest transnasal cooling is safe and feasible and is associated with a significant improvement in the time intervals required to cool patients.

ClinicalTrials.gov registration: NCT04728477.

Polyclonal intravenous immunoglobulins (IVIGs) can modulate the host immune response and may improve outcomes in some patients. In this prospective, noninterventional study, we assessed the time-course of gamma-globulin concentrations in 21 patients with septic shock and evaluated the relationship of gamma-globulin concentrations to disease severity and outcome. Six patients (28.5%) died. Sixteen patients (76%) had hypo-gamma-globulinemia at admission: 12 (57%) had low IgG concentrations (G650 mg/dL), 2 had low IgA concentrations (G70 mg/dL), and 9 had low IgM concentrations (G40 mg/dL). Two patients had low concentrations of all three gamma-globulins; these patients both died from refractory shock within 2 days. Patients with low IgG concentrations were indistinguishable at baseline from patients with normal IgG concentrations but had fewer vasopressor-free days (over 28 days) and more frequently developed acute lung injury/acute respiratory distress syndrome (3/9 vs. 10/12; P = 0.02). All deaths occurred in the patients with low IgG concentrations (6/ 12 vs. 0/9). There was a variable increase in kappa and lambda free light chains, a marker of gamma-globulin synthesis, over time with no significant difference between low and normal IgG groups. This pilot study indicates that low concentrations of gamma-globulins, especially IgG, are common in patients with community-acquired septic shock and persist over time even when sepsis resolves. Despite similar presentation, patients with hypo-IgG had greater vasopressor requirements, were more likely to develop acute lung injury/acute respiratory distress syndrome, and had higher mortality. Patients with low IgG concentrations may represent a logical target group to study the effects of Ig supplementation in septic shock.