Implementation of a software-based decision support tool for guideline-appropriate preoperative evaluation: a prospective agreement study.

Background: Guideline adherence in the medical field leaves room for improvement. Digitalised decision support helps improve compliance. However, the complex nature of the guidelines makes implementation in clinical practice difficult.

Anaesthesiologists' guideline adherence in pre-operative evaluation: a retrospective observational study.

Background: Surveys suggest a low level of implementation of clinical guidelines, although they are intended to improve the quality of treatment and patient safety. Which guideline recommendations are not followed and why has yet to be analysed. In this study, we investigate the proportion of European and national guidelines followed in the area of pre-operative anaesthetic evaluation prior to non-cardiac surgery.

Susceptibility of AutoML mortality prediction algorithms to model drift caused by the COVID pandemic.

Background: Concept drift and covariate shift lead to a degradation of machine learning (ML) models. The objective of our study was to characterize sudden data drift as caused by the COVID pandemic. Furthermore, we investigated the suitability of certain methods in model training to prevent model degradation caused by data drift.

Enabling personalized perioperative risk prediction by using a machine-learning model based on preoperative data.

Preoperative risk assessment is essential for shared decision-making and adequate perioperative care. Common scores provide limited predictive quality and lack personalized information. The aim of this study was to create an interpretable machine-learning-based model to assess the patient's individual risk of postoperative mortality based on preoperative data to allow analysis of personal risk factors.

Sex-specific issues of central and peripheral arginine-vasopressin concentrations in neurocritical care patients.

Background: Arginine-Vasopressin (AVP) is a nonapeptide that exerts multiple functions within the central nervous system and in the blood circulation that might contribute to outcome in critically ill patients. Sex differences have been found for mental and physical effects of AVP. For example, stress response and response due to hemorrhage differ between males and females, at least in animal studies.

Anterior Pituitary Hormones in Blood and Cerebrospinal Fluid of Patients in Neurocritical Care.

Background: Anterior pituitary hormones in blood follow a circadian rhythm, which may be influenced by various factors such as intracranial pathologies. In cerebrospinal fluid (CSF), pituitary hormones have been collected only selectively and circadian rhythm has not yet been investigated. This pilot study analysed diurnal variations of anterior pituitary hormones in patients in neurocritical care to determine whether circadian rhythmicity exists in these patients.

Absence of a diurnal rhythm of oxytocin and arginine-vasopressin in human cerebrospinal fluid, blood and saliva.

Purpose: The aims of our study were to determine first circadian influences on central concentrations of the neuropeptides oxytocin and arginine-vasopressin and second to investigate if these central concentrations are associated with those in the peripheral compartments blood and saliva in neurocritical care patients. We therefore included patients with external ventricular drain who attended a neurosurgical intensive care unit and were not exposed to painful or stressful stimuli during the sampling period. For this purpose, blood, cerebrospinal fluid and saliva were collected in a 24-hour-interval at the timepoints 06:00, 12:00, 18:00 and 24:00.

Weak correlations between serum and cerebrospinal fluid levels of estradiol, progesterone and testosterone in males.

Background: Neuroactive steroids seem to be implicated in a variety of neurophysiological and behavioral processes, such as sleep, learning, memory, stress, feeding and aging. Numerous studies have also addressed this implication in various cerebral disorders and diseases. Yet, the correlation and association between steroids in the periphery, e.

Influence of perioperative stress on central and peripheral oxytocin and arginine-vasopressin concentrations.

Perioperative stress provides not only physical, but also psychic and emotional aspects, which may influence the hypothalamic neuropeptide system. Studies investigating the perioperative course of central neuropeptide activity are missing. Therefore, the present study aimed to determine perioperative fluctuations in central and concomitant peripheral concentrations of the hypothalamic neuropeptides oxytocin (OXT) and arginine-vasopressin (AVP), as well as their impact on perioperative anxiety and depression.

Influence of sex and hormonal status on initial impact and neurocognitive outcome after subarachnoid haemorrhage in rats.

The aim of this study was to detect differences in functional outcome after experimental subarachnoid haemorrhage (SAH) in rodents with different hormonal status. For this purpose, the endovascular perforation model was applied to four groups of Sprague-Dawley-Rats: male intact, male neutered, female intact and female neutered animals. Initial impact was measured by ICP, CPP and cerebral blood flow in the first hour after SAH.

Oxytocin levels in saliva correlate better than plasma levels with concentrations in the cerebrospinal fluid of patients in neurocritical care.

In the converging fields of neuroendocrinology and behavioural neuroscience, the interaction between peripheral secretion and central release of oxytocin in humans has not yet been comprehensively assessed. As the human brain is not directly accessible and as the collection of human cerebrospinal fluid (CSF) usually requires invasive procedures, easier accessible compartments such as blood or saliva attract increasing attention. In this study, we prospectively determined oxytocin concentrations in the three compartments plasma, CSF and saliva of fifty critically ill patients with neurological and neurosurgical diseases.

The influence of PEEP and tidal volume on central blood volume.

Background And Objective: Measurement of central blood volumes (CBV), such as global end-diastolic volume (GEDV) and right ventricular end-diastolic volume (RVEDV) are considered appropriate estimates of intravascular volume status. However, to apply those parameters for preload assessment in mechanically ventilated patients, the influence of tidal volume (TV) and positive endexpiratory airway pressure (PEEP) on those parameters must be known.

Methods: In 13 mechanically ventilated piglets, the effect of low (10 mL kg(-1)) and high (20 mL kg(-1)) TVs on CBV was investigated in absence and presence of PEEP (0 and 15 cm H(2)O).

The influence of cardiac preload and positive end-expiratory pressure on the pre-ejection period.

The pre-ejection period (PEP) has recently been described as a potential parameter for monitoring cardiac preload. This study further investigated the influence of changes in intravascular volume status and the application of positive end-expiratory pressure (PEEP) on the pre-ejection period. In ten pigs, ECG, arterial pressure and stroke volume derived from an aortic flowprobe were registered.

[Acute normovolemic hemodilutin (ANH). Effects of ANH on the diastolic function of the left ventricle].

Ischemia-induced changes of diastolic leftventricular (LV) properties commonly precede corresponding ECG-changes. In the present experimental study the consequences of acute normovolemic hemodilution (ANH) induced dilutional anemia (hematocrit, hct 20%) for LV diastolic function were investigated. A total of 22 anaesthetized, splenectomized beagle dogs breathing room air were hemodiluted with isooncotic hydroxyethylstarch solution (6% HAES 200,000/0.

Effect of acute normovolemic hemodilution on distribution of blood flow and tissue oxygenation in dog skeletal muscle.

Acute normovolemic hemodilution (ANH) is efficient in reducing allogenic blood transfusion needs during elective surgery. Tissue oxygenation is maintained by increased cardiac output and oxygen extraction and, presumably, a more homogeneous tissue perfusion. The aim of this study was to investigate blood flow distribution and oxygenation of skeletal muscle.

IV perflubron emulsion versus autologous transfusion in severe normovolemic anemia: effects on left ventricular perfusion and function.

Intact cardiac compensatory mechanisms are necessary to maintain adequate tissue oxygenation during acute normovolemic hemodilution (ANH). Left ventricular (LV) perfusion, oxygenation and function were analyzed in an experimental whole-body model of profound ANH (Hct 9%) and effectiveness of a perfluorocarbon-based oxygen carrier in maintaining myocardial oxygenation and function was evaluated. A total of 22 anesthetized dogs were hemodiluted to Hct 20% followed by a simulated, controlled blood-loss phase in which dogs were randomized to either: (1) 1:1 exchange of lost blood with autologous red blood cells (RBC-group), (2) 1:1 exchange with a colloid (control-group) and (3) 1:1 exchange with a colloid after a single dose of 1.

Normovolaemic haemodilution and hyperoxia have no effect on fractal dimension of regional myocardial perfusion in dogs.

Hypervolaemic haemodilution makes myocardial perfusion more homogenous as reflected by reduced fractal dimension of regional myocardial perfusion. The clinically more commonly performed acute normovolaemic haemodilution, however, has not yet been studied in this respect. Hyperoxic ventilation with 100% oxygen is used in conjunction with haemodilution to compensate for low oxygen content by increasing physically dissolved oxygen in plasma.

Hemodilution and intravenous perflubron emulsion as an alternative to blood transfusion: effects on tissue oxygenation during profound hemodilution in anesthetized dogs.

Background: Intravenously administered perfluorocarbon (PFC) emulsions increase oxygen solubility in plasma. PFC might therefore temporarily replace red cells (RBCs) lost during intraoperative hemorrhage. In patients who have undergone hemodilution, the return of autologous blood may be delayed by the administration of PFC, and autologous RBCs may be saved for transfusion after surgical bleeding is stopped and PFC is cleared by the reticuloendothelial system.

Effects of hyperoxic ventilation on hemodilution-induced changes in anesthetized dogs.

Background: In subjects who have undergone acute preoperative normovolemic hemodilution (ANH), intraoperative hemorrhage is generally treated by immediate return of autologous blood collected during ANH. Simply increasing blood oxygen content by hyperoxic ventilation (HV, inspiratory fraction [FIO2] 1.0) might compensate for the acute anemia, allow further ANH, and delay onset of autologous blood return.

Hemodilution and hyperoxia locally change distribution of regional pulmonary perfusion in dogs.

In seven anesthetized dogs, the effects of acute normovolemic hemodilution (ANH) to a hematocrit of 20 and 8% and the effects of hyperoxic ventilation (100% oxygen) on distribution of regional pulmonary blood flow (rPBF; radioactive microspheres) were investigated. Normovolemia was monitored with blood volume measurements (indocyanine green dilution kinetics). Before ANH, fractal dimension (D) of rPBF in the whole lung was 1.

Effects of hemodilution on splanchnic perfusion and hepatorenal function. II. Renal perfusion and hepatorenal function.

Hepatorenal perfusion and function were assxssed in 22 dogs undergoing acute normovolemic hemodilution (ANH) to a hematocrit (Hct) of 20% using 6% hydroxyethyl starch (200.000/0.5) as the diluent.

Effects of hemodilution on splanchnic perfusion and hepatorenal function. I. Splanchnic perfusion.

Perfusion of intestinal organs increases in response to acute normovolemic hemodilution (ANH). However, detailed studies on distribution of regional splanchnic organ perfusion during ANH are lacking. We therefore carried out this study to test the hypothesis that ANH does not cause disturbance of physiologic patterns of regional splanchnic organ blood flow.

Effects of hemodilution on gastric regional perfusion and intramucosal pH.

Unlabelled: Acute normovolemic hemodilution (ANH) has been shown to be a cost-effective method of reducing allogenic blood transfusion during elective surgery. ANH has been implicated with impaired oxygenation in isolated canine gastric flaps. The present study was designed to investigate the effects of ANH on gastric mucosal oxygenation using a model closely imitating the clinical situation.