Marked hemoglobin mass expansion and plasma volume contraction in Sherpas acclimatizing to 5,400 m altitude.

In lowlanders, high altitude (HA) acclimatization induces hemoconcentration by reducing plasma volume (PV) and increasing total hemoglobin mass (Hb). Conversely, Tibetan highlanders living at HA are reported to have a similar hemoglobin concentration ([Hb]) as lowlanders near sea level, and we investigated whether this reflects alterations in the PV or the Hb response to HA. Baseline assessment of PV and Hb was performed by carbon monoxide rebreathing at low altitudes (∼1,400 m) in Sherpas (an ethnic group of Tibetans living in Nepal) and native lowlanders.

Expert perspectives on ECCOR for acute hypoxemic respiratory failure: consensus of a 2022 European roundtable meeting.

Background: By controlling hypercapnia, respiratory acidosis, and associated consequences, extracorporeal CO removal (ECCOR) has the potential to facilitate ultra-protective lung ventilation (UPLV) strategies and to decrease injury from mechanical ventilation. We convened a meeting of European intensivists and nephrologists and used a modified Delphi process to provide updated insights into the role of ECCOR in acute respiratory distress syndrome (ARDS) and to identify recommendations for a future randomized controlled trial.

Results: The group agreed that lung protective ventilation and UPLV should have distinct definitions, with UPLV primarily defined by a tidal volume (V) of 4-6 mL/kg predicted body weight with a driving pressure (ΔP) ≤ 14-15 cmHO.

The physiological basis for individualized oxygenation targets in critically ill patients with circulatory shock.

Background: Circulatory shock, defined as decreased tissue perfusion, leading to inadequate oxygen delivery to meet cellular metabolic demands, remains a common condition with high morbidity and mortality. Rapid restitution and restoration of adequate tissue perfusion are the main treatment goals. To achieve this, current hemodynamic strategies focus on adjusting global physiological variables such as cardiac output (CO), hemoglobin (Hb) concentration, and arterial hemoglobin oxygen saturation (SaO).

The microcirculation in the first days of ICU admission in critically ill COVID-19 patients is influenced by severity of disease.

The objective of this study was to investigate the relationship between sublingual microcirculatory parameters and the severity of the disease in critically ill coronavirus disease 2019 (COVID-19) patients in the initial period of Intensive Care Unit (ICU) admission in a phase of the COVID-19 pandemic where patients were being treated with anti-inflammatory medication. In total, 35 critically ill COVID-19 patients were included. Twenty-one critically ill COVID-19 patients with a Sequential Organ Failure Assessment (SOFA) score below or equal to 7 were compared to 14 critically ill COVID-19 patients with a SOFA score exceeding 7.

Beta-adrenergic blockade increases pulmonary vascular resistance and causes exaggerated hypoxic pulmonary vasoconstriction at high altitude: a physiological study.

Background: An increasing number of hypertensive persons travel to high altitude (HA) while using antihypertensive medications such as beta-blockers. Nevertheless, while hypoxic exposure initiates an increase in pulmonary artery pressure (Ppa) and pulmonary vascular resistance (PVR), the contribution of the autonomic nervous system is unclear. In animals, beta-adrenergic blockade has induced pulmonary vasoconstriction in normoxia and exaggerated hypoxic pulmonary vasoconstriction (HPV) and both effects were abolished by muscarinic blockade.

Effects of enhanced adsorption haemofiltration versus haemoadsorption in severe, refractory septic shock with high levels of endotoxemia: the ENDoX bicentric, randomized, controlled trial.

Background: Endotoxin adsorption is a promising but controversial therapy in severe, refractory septic shock and conflicting results exist on the effective capacity of available devices to reduce circulating endotoxin and inflammatory cytokine levels.

Methods: Multiarm, randomized, controlled trial in two Swiss intensive care units, with a 1:1:1 randomization of patients suffering severe, refractory septic shock with high levels of endotoxemia, defined as an endotoxin activity ≥ 0.6, a vasopressor dependency index ≥ 3, volume resuscitation of at least 30 ml/kg/24 h and at least single organ failure, to a haemoadsorption (Toraymyxin), an enhanced adsorption haemofiltration (oXiris) or a control intervention.

The microcirculation in perioperative medicine: a narrative review.

The microcirculation describes the network of the smallest vessels in our cardiovascular system. On a microcirculatory level, oxygen delivery is determined by the flow of oxygen-carrying red blood cells in a given single capillary (capillary red blood cell flow) and the density of the capillary network in a given tissue volume (capillary vessel density). Handheld vital videomicroscopy enables visualisation of the capillary bed on the surface of organs and tissues but currently is only used for research.

Microcirculatory Monitoring in Children with Congenital Heart Disease Before and After Cardiac Surgery.

In this prospective observational study, we investigated whether congenital heart disease (CHD) affects the microcirculation and whether the microcirculation is altered following cardiac surgery with cardiopulmonary bypass (CPB). Thirty-eight children with CHD undergoing cardiac surgery with CPB and 35 children undergoing elective, non-cardiac surgery were included. Repeated non-invasive sublingual microcirculatory measurements were performed with handheld vital microscopy.

Donor-derived fulminant herpes simplex virus hepatitis after liver transplantation: Two cases and review of literature.

Background: Fulminant herpetic hepatitis due to herpes simplex virus (HSV), serotype 1 or 2, is a rare but often fatal complication after solid organ transplantation (SOT). HSV hepatitis in SOT recipients can occur either due to primary infection acquired post transplantation, viral reactivation in a seropositive patient, or as donor-derived infection. Cases of fatal hepatitis have been reported in the liver as well as in other SOT recipients.

Do cardiopulmonary exercise tests predict summit success and acute mountain sickness? A prospective observational field study at extreme altitude.

Objective: During a high-altitude expedition, the association of cardiopulmonary exercise testing (CPET) parameters with the risk of developing acute mountain sickness (AMS) and the chance of reaching the summit were investigated.

Methods: Thirty-nine subjects underwent maximal CPET at lowlands and during ascent to Mount Himlung Himal (7126 m) at 4844 m, before and after 12 days of acclimatisation, and at 6022 m. Daily records of Lake-Louise-Score (LLS) determined AMS.

Identifying a sublingual triangle as the ideal site for assessment of sublingual microcirculation.

The sublingual mucosa is a commonly used intraoral location for identifying microcirculatory alterations using handheld vital microscopes (HVMs). The anatomic description of the sublingual cave and its related training have not been adequately introduced. The aim of this study was to introduce anatomy guided sublingual microcirculatory assessment.

Artificial intelligence in intensive care: moving towards clinical decision support systems.

The high complexity of care in the Intensive Care Unit environment has led, in the last decades, to a big effort in term of the improvement of patient's monitoring devices, increase of diagnostic and therapeutic opportunities, and development of electronic health records. Such advancements have enabled an increasing availability of large amounts of data that were supposed to provide more insight and understanding regarding pathophysiological processes and patient's prognosis providing useful tools able to support physicians in the clinical decision-making process. On the contrary, the interpolation, analysis, and interpretation of a such big amount of data has soon proven to be much more complicated than expected, opening the way for the development of tools based on machine learning (ML) algorithms.

Microcirculatory alterations in critically ill COVID-19 patients analyzed using artificial intelligence.

Background: The sublingual microcirculation presumably exhibits disease-specific changes in function and morphology. Algorithm-based quantification of functional microcirculatory hemodynamic variables in handheld vital microscopy (HVM) has recently allowed identification of hemodynamic alterations in the microcirculation associated with COVID-19. In the present study we hypothesized that supervised deep machine learning could be used to identify previously unknown microcirculatory alterations, and combination with algorithmically quantified functional variables increases the model's performance to differentiate critically ill COVID-19 patients from healthy volunteers.

Dynamics of disease characteristics and clinical management of critically ill COVID-19 patients over the time course of the pandemic: an analysis of the prospective, international, multicentre RISC-19-ICU registry.

Background: It remains elusive how the characteristics, the course of disease, the clinical management and the outcomes of critically ill COVID-19 patients admitted to intensive care units (ICU) worldwide have changed over the course of the pandemic.

Methods: Prospective, observational registry constituted by 90 ICUs across 22 countries worldwide including patients with a laboratory-confirmed, critical presentation of COVID-19 requiring advanced organ support. Hierarchical, generalized linear mixed-effect models accounting for hospital and country variability were employed to analyse the continuous evolution of the studied variables over the pandemic.

Microcirculatory tissue perfusion during general anaesthesia and noncardiac surgery: An observational study using incident dark field imaging with automated video analysis.

Background: Handheld vital microscopy allows direct observation of red blood cells within the sublingual microcirculation. Automated analysis allows quantifying microcirculatory tissue perfusion variables - including tissue red blood cell perfusion (tRBCp), a functional variable integrating microcirculatory convection and diffusion capacities.

Objective: We aimed to describe baseline microcirculatory tissue perfusion in patients presenting for elective noncardiac surgery and test that microcirculatory tissue perfusion is preserved during elective general anaesthesia for noncardiac surgery.

Critical care staffing ratio and outcome of COVID-19 patients requiring intensive care unit admission during the first pandemic wave: a retrospective analysis across Switzerland from the RISC-19-ICU observational cohort.

Study Aim: The surge of admissions due to severe COVID-19 increased the patients-to-critical care staffing ratio within the ICUs. We investigated whether the daily level of staffing was associated with an increased risk of ICU mortality (primary endpoint), length of stay (LOS), mechanical ventilation and the evolution of disease (secondary endpoints).

Methods: We employed a retrospective multicentre analysis of the international Risk Stratification in COVID-19 patients in the ICU (RISC-19-ICU) registry, limited to the period between March 1 and May 31, 2020, and to Switzerland.

Morphologic Mapping of the Sublingual Microcirculation in Healthy Volunteers.

Purpose: Monitoring the sublingual and oral microcirculation (SM-OM) using hand-held vital microscopes (HVMs) has provided valuable insight into the (patho)physiology of diseases. However, the microvascular anatomy in a healthy population has not been adequately described yet.

Methods: Incident dark field-based HVM imaging was used to visualize the SM-OM.