[Occupational safety in the treatment of COVID-19 patients : Relevant laws and regulations for the treating personnel]. / Arbeitsschutz bei der Versorgung von COVID-19-Patienten : Relevante Gesetze und Regelungen für das versorgende Personal.

The intensive medical care of COVID-19 patients presents the deployed personnel with as yet unknown challenges. For example, protective equipment is now being extensively used, which was otherwise only used in selected situations. Working in such an environment is to be evaluated differently under the aspect of occupational safety than other patient care, especially as more than 1900 suspected cases of a SARS-CoV-19 occupational disease were reported among healthcare workers in Germany. Even in a pandemic, the legal requirements remain valid and personal protective equipment (PPE) has to comply with given standards. The use of FFP3 masks is required in aerosol-forming situations, such as endotracheal intubation or bronchoscopy. In contrast to surgical face masks, there is a maximum wearing time for FFPs masks. Furthermore, in a pandemic there is a basic danger of PPE shortage and recycling of face masks is under discussion. Therefore, usage of non-EU certified PPE may come into effect but this has to follow the requirements defined by European regulations. The aim of this article is to provide an overview of the currently relevant rules and regulations in Germany.

Comparison of sedation and general anaesthesia for transcatheter aortic valve implantation on cerebral oxygen saturation and neurocognitive outcome†.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) is a treatment strategy for patients with severe aortic stenosis. Although general anaesthesia (TAVI-GA) and sedation (TAVI-S) have previously been described for TAVI, the difference in safety and efficacy of both methods has not been studied in a randomized trial. METHODS: The INSERT trial was a single centre, controlled parallel-group trial with balanced randomization. Sixty-six patients (68-94 yr) with acquired aortic stenosis undergoing transfemoral CoreValve™ were assigned to TAVI-GA or TAVI-S. Comparable operative risk was determined from risk-scores (EUROscore, STS-Score). Monitoring and anaesthetic drugs were standardized. Near-Infrared-Spectroscopy was used to monitor cerebral-oxymetry blinded. Primary outcome was the perioperative cumulative cerebral desaturation. As secondary outcomes, changes in neurocognitive function and respiratory and haemodynamic adverse events were evaluated. RESULTS: Of 66 included patients, 62 (TAVI-GA: n=31, TAVI-S: n=31) were finally analysed. Baseline characteristics were comparable. In 24 patients (39%) cerebral desaturation was observed. Cumulative cerebral desaturation was comparable (TAVI-GA:(median [IQR]) (0[0/1308] s%) vs. TAVI-S:(0[0/276] s%); P=0.505) between the groups. Neurocognitive function did not change within and between groups. Adverse events were more frequently observed in TAVI-S patients (P<0.001). Bradypnoea (n=16, 52%) and the need for airway manoeuvres (n=11, 36%) or bag-mask-ventilation (n=6, 19%) were the most common respiratory adverse events. CONCLUSIONS: Cerebral desaturation occurred in both patient groups, but there was no significant difference between the two groups. Based on primary outcome, both methods were shown to be comparable. Neurocognitive outcome was similar. The higher incidence of adverse events in the sedation group suggests a potential advantage of general anaesthesia. CLINICAL TRIAL REGISTRATION: NCT 01251328.

Ejection fractions and pressure-heart rate product to evaluate cardiac efficiency. Continuous, real-time diagnosis using blood pressure and heart rate.

INTRODUCTION: Ejection fractions, derived from ventricular volumes, and double product, related to myocardial oxygen consumption, are important diagnostic parameters, as they describe the efficiency with which oxygen is consumed. Present technology often allows only intermittent determination of physiological status. This deficiency may be overcome if ejection fractions and myocardial oxygen consumption could be determined from continuous blood pressure and heart rate measurements. The purpose of this study is to determine the viability of pressure-derived ejection fractions and pressure-heart rate data in a diverse patient population and the use of ejection fractions to monitor patient safety. METHODS: Volume ejection fractions, derived from ventricular volumes, EF(V), are defined by the ratio of the difference of end-diastolic volume, EDV, and end-systolic volume, ESV, to EDV. In analogy, pressure ejection fraction, EF(P), may be defined by the ratio of the difference of systolic arterial pressure, SBP, and diastolic arterial pressure, DBP, to SBP. The pressure-heart rate (heart rate: HR) is given by the product of systolic pressure and heart rate, SBP × HR. EF(P) and SBP × HR data were derived for all patients (n = 824) who were admitted in 2008 to the ICU of a university hospital at the specific time 30 min prior to leaving the ICU whether as survivors or non-survivors. The results are displayed in an efficiency/pressure-heart rate diagram. RESULTS: The efficiency/pressure-heart rate diagram reveals one subarea populated exclusively by survivors, another subarea populated statistically significant by non-survivors, and a third area shared by survivors and non-survivors. DISCUSSION AND CONCLUSION: The efficiency/pressure-heart rate product relationship may be used as an outcome criterion to assess survival and to noninvasively monitor improvement or deterioration in real time to improve safety in patients with diverse dysfunctions.

[Postoperative acute mitral regurgitation. Unexpected finding after minor non-cardiac surgery]. / Akute perioperative Mitralklappeninsuffizienz. Unerwarteter Befund nach nichtkardiochirurgischem Bagatelleingriff.

This report describes the case of a 59-year-old man who was scheduled for general anesthesia with propofol, sufentanil and sevoflurane for removal of a metal implant. The patient was classified as American Society of Anesthesiologists (ASA) II status because of an asymptomatic mitral valve prolapse and medically treated arterial hypertension. During induction of narcosis a pulsoxymetrically measured inadequate increase in oxygen saturation after preoxygenation was noticed and a moderate respiratory obstruction occurred intraoperatively, but anesthesia was uneventfully completed and the patient was extubated. However, 3 h later the patient developed severe dyspnea, hypoxia, tachycardia and arterial hypotension. Physical examination revealed a new grade 4/6 systolic murmur radiating to the axilla and X-ray showed bilateral pulmonary edema. Neither electrocardiographic nor biochemical manifestations of acute myocardial infarction were identified but transthoracic echocardiography revealed fluttering of the posterior leaflet of the mitral valve with grade III regurgitation and dilation of the left atrium. Coronary angiography was normal and left ventriculography confirmed severe mitral regurgitation. Mitral valve repair was successfully performed 22 h after presentation of symptoms. Mitral regurgitation is a common finding on echocardiography, seen to some degree in over 75% of the population. The etiology of mitral valve insufficiency which can be caused by pathologic changes of one or more of the components of the mitral valve, including the leaflets, annulus, chordae tendineae, papillary muscles, or by abnormalities of the surrounding left ventricle and/or atrium are discussed. Rupture of mitral chordae tendineae is infrequent and causes acute hemodynamic deterioration and needs corrective surgery. Valve replacement should be performed only if mitral valve repair is not possible. Echocardiography is an invaluable tool in determining the severity of regurgitation, the integrity of the mitral valve apparatus, the extent of left ventricular enlargement, and the ejection fraction. Acute mitral valve regurgitation caused by a rupture of chordae tendineae should be considered in the differential diagnosis of perioperative acute pulmonary edema.

Can we do without routine fenestration in extracardiac total cavopulmonary connections? Report on 84 consecutive patients.

Fenestration is still widely used in right heart bypass operations. Our study was conducted to assess its need in the most recent modification, the completion of a total cavopulmonary connection with an extracardiac tube. The extracardiac approach was introduced at our institution in January, 1999. Since June of 2000, no patient had a fenestration. If more than 1 risk factor amongst ventricular function being more than moderately impaired, atrioventricular valvar regurgitation more than moderate, mean pulmonary arterial pressure more than 15 millimetres of mercury, mean atrial pressure higher than 12 millimetres of mercury, pulmonary arterial distortion, or other than sinus rhythm was present preoperatively, the patient was considered a "high risk" candidate. Postoperatively elevated pulmonary arterial pressure higher than 16 millimetres of mercury, prolonged effusions and requirement for drainage longer than 7 days, and death were considered endpoints in the statistical analysis. Our study group included 84 patients who underwent surgery up to August, 2004. A previous bidirectional cavopulmonary anastomosis had been accomplished in 73 patients at a mean age of 27.01 plus or minus 32.60 months, with a median of 11.5 months, without creating an additional source of flow of blood to the lungs. At the time of the total cavopulmonary connection, the mean age was 66.4 plus or minus 60.1 months, with a median of 37.1 months, and a range from 17.3 to 251.2 months, with 50 patients being younger than 48 months. We deemed 16 patients to be at "high risk". These patients were older at the time of bidirectional cavopulmonary anstomosis (p smaller than 0.016), at the time of completion (p smaller than 0.019), and also differed in size at time of completion (p smaller than 0.020). They required a longer time on cardiopulmonary bypass (p smaller than 0.015), and reached higher early postoperative pulmonary arterial pressures after completion (p smaller than 0.025). There were no differences between groups of patients having up to 1 or more risk factors in regard to need for intubation (p smaller than 0.511), pulmonary arterial pressures after extubation (p smaller than 0.817), and duration of chest drainage (p smaller than 0.650). Three patients died, one in the group deemed at high risk. There was no death in the last 38 patients. We conclude that a total cavopulmonary connection with an extracardiac tube can be performed without fenestration, even if the patients are deemed to be at increased risk. Early staging of patients with functionally univentricular physiology might be one of the keys for these findings.

Determinants of cerebral oxygenation during cardiac surgery.

BACKGROUND: Neuropsychological deficits after cardiac surgery are attributed to the side effects of cardiopulmonary bypass (CPB). To protect the brain from ischemic damage, the influences of temperature, blood pressure, blood gases, acid-base status, and hemodilution on cerebral oxygenation have to be elucidated and quantified. METHODS: Forty-one consecutive patients were investigated during cardiac surgery while on CPB. Operative management included moderate hypothermia of 26 degrees C and the alpha-stat pH management. With near-infrared spectrophotometry, changes in oxygenated hemoglobin (HbO2, representing oxygen delivery) and oxidized cytochrome a,a3 (CtO2, cellular oxygenation) in brain tissue were obtained noninvasively. In addition, venous saturation of the brain was measured via a catheter in the jugular bulb (SBJO2). The influence of operative management parameters on cerebral oxygenation was calculated by univariate and multiple regression analyses. RESULTS: Before and after CPB there was no significant multivariate determinant of cerebral oxygenation. During CPB, HbO2 depended solely on PCO2 (P < .01; r = .89). CtO2 was determined by pH (P < .01), esophageal temperature (P < .01), PCO2 (P < .01), and Hb (P < .01). These parameters explained nearly all changes of the cytochrome measurements during CPB (r = .99). Arterial PCO2 (P < .01) and pH (P < .01) influenced brain venous oxygen saturation (SBJO2; r = .98). CONCLUSIONS: Cerebral oxygenation is autoregulated during cardiac surgery before and after CPB. During CPB, Hb, temperature, pH, and PCO2 determined at least 85% of all changes in cerebral oxygenation. The main causes of impaired cerebral oxygenation are the decrease in Hb with hemodilution, vasoconstriction due to hypocapnia, and the leftward shift of the Hb binding curve in alkalosis and hypothermia.

Postoperative neuropsychological dysfunction and cerebral oxygenation during cardiac surgery.

In 41 patients undergoing cardiac operations with extracorporeal circulation, oxidized cytochrome a,a3(CtO2), deoxygenated hemoglobin (Hb), and oxygenated hemoglobin (HbO2) were measured in brain tissue by near-infrared spectrophotometry (NIRS) intraoperatively. Monitoring also included electroencephalography (EEG) and jugular-bulb venous saturation (SBJO2). All operations were performed using membrane oxygenators, moderate hypothermia (26-28 degrees C) and pH alpha-stat management. During cardiopulmonary bypass (CPB) CtO2 and HbO2) were reduced, reaching minimal values when rewarming was instituted. At the end of the operation CtO2 and HbO2 had regained initial levels. During CPB, arterial PCO2, pH, and temperature were closely related to CtO2 (r = 1000, r = -0.964 and 0.929 respectively; p < 0.001, p < 0.001, and p < 0.003 respectively). Neuropsychological testing by the Mini-Mental-State Test indicated reversible postoperative neuropsychological deficits in four patients. There patients had a lower CtO2 minimum compared to those without these deficits (-4.5 mumol/L v. -0.7 mumol/L; p = 0.036). These findings support the hypothesis that neuropsychological deficits in patients after cardiac surgery can be caused by intraoperative cerebral hypoxia.