Risk factors for nosocomial SARS-CoV-2 infections in patients: results from a retrospective matched case–control study in a tertiary care university center

Background: Factors contributing to the spread of SARS-CoV-2 outside the acute care hospital setting have been described in detail. However, data concerning risk factors for nosocomial SARS-CoV-2 infections in hospitalized patients remain scarce. To close this research gap and inform targeted measures for the prevention of nosocomial SARS-CoV-2 infections, we analyzed nosocomial SARS-CoV-2 cases in our hospital during a defined time period. Methods: Data on nosocomial SARS-CoV-2 infections in hospitalized patients that occurred between May 2020 and January 2021 at Charite university hospital in Berlin, Germany, were retrospectively gathered. A SARS-CoV-2 infection was considered nosocomial if the patient was admitted with a negative SARS-CoV-2 reverse transcription polymerase chain reaction test and subsequently tested positive on day five or later. As the incubation period of SARS-CoV-2 can be longer than five days, we defined a subgroup of "definite" nosocomial SARS-CoV-2 cases, with a negative test on admission and a positive test after day 10, for which we conducted a matched case-control study with a one to one ratio of cases and controls. We employed a multivariable logistic regression model to identify factors significantly increasing the likelihood of nosocomial SARS-CoV-2 infections. Results: A total of 170 patients with a nosocomial SARS-CoV-2 infection were identified. The majority of nosocomial SARS-CoV-2 patients (n = 157, 92%) had been treated at wards that reported an outbreak of nosocomial SARS-CoV-2 cases during their stay or up to 14 days later. For 76 patients with definite nosocomial SARS-CoV-2 infections, controls for the case-control study were matched. For this subgroup, the multivariable logistic regression analysis revealed documented contact to SARS-CoV-2 cases (odds ratio: 23.4 (95% confidence interval: 4.6-117.7)) and presence at a ward that experienced a SARS-CoV-2 outbreak (odds ratio: 15.9 (95% confidence interval: 2.5-100.8)) to be the principal risk factors for nosocomial SARS-CoV-2 infection. Conclusions: With known contact to SARS-CoV-2 cases and outbreak association revealed as the primary risk factors, our findings confirm known causes of SARS-CoV-2 infections and demonstrate that these also apply to the acute care hospital setting. This underscores the importance of rapidly identifying exposed patients and taking adequate preventive measures

The influence of goal-directed fluid therapy on the clinical outcome of patients after transcatheter aortic valve replacement – an ambispective analysis

Die Aufrechterhaltung bzw. Optimierung eines ausgeglichenen Volumenstatus während chirurgischer Eingriffe sowie auf der Intensivstation gehört zu den wichtigsten Aufgaben eines Anästhesisten bzw. Intensivmediziners. Eine Protokoll-orientierte Optimierung von ausgewählten hämodynamischen Parametern im Sinne einer Goal-directed-Therapy (GDT) hat in diesem Kontext zu einer Verbesserung des Patienten-Outcomes in unterschiedlichen perioperativen Settings geführt. Patienten, die eine perkutane transfemorale oder transapikale Aortenklappenimplantation (TAVI) bekommen, sind häufig ältere und multimorbide Patienten, bei denen ein offen chirurgisches Vorgehen aufgrund erheblicher operativer Risiken nicht indiziert ist. Gerade in dieser Kohorte ist die Optimierung des Volumenstatus von besonderer Wichtigkeit. Die Anwendbarkeit sowie die Sinnhaftigkeit einer GDT ist bislang jedoch noch nicht untersucht worden. Bei 40 TAVI Patienten wurden mittels Pulskonturanalyse das Schlagvolumen (SV) und die Schlagvolumenvariation (SVV) prä- und intraoperativ wiederholt bestimmt und das Schlagvolumen wurde durch die intravenöse Gabe von 250ml kolloidaler Flüssigkeit (6 % HAES 130/0,4) optimiert (Interventionsgruppe). Diese Gruppe wurde mit einer retrospektiven TAVI-Kohorte vor Implementierung einer GDT (n=40) verglichen (Kontrollgruppe). Bei den Patienten der Interventionsgruppe konnte durch die zielgerichtete Volumengabe eine Steigerung des Schlagvolumens nach der Narkoseeinleitung erreicht werden (SV nach Einleitung 60 [42; 67] vs. SV nach Optimierung 70 [58; 92], p=0,003). Entsprechend des Protokoll-Designs erhielten die Patienten der Interventionsgruppe mehr kolloidale (750 [500; 1000] vs. 500 [0; 500], p<0,001) und weniger Kristalloide (500 [0; 500 vs. 500 [500; 1000], p<0,001) Infusionslösungen. Die gesamte Volumengabe blieb allerdings nicht unterschiedlich. Die Interventionsgruppe war mit einer geringeren Rate an postoperativem Delir assoziiert (17 vs. 6). Das Protokoll konnte also für die perioperative Optimierung des Schlagvolumens erfolgreich angewendet werden. Die Optimierung des Schlagvolumens war dabei mit einer Reduktion des Auftretens eines postoperativen Delirs assoziiert. Prospektiv angelegte randomisierte Studien mit für diese Outcomes gepowerter Patientenanzahl und längerem Follow-Up sind nötig, um die Effektivität dieser Strategie in diesem Sinne zu bestätigen.The maintenance of normovolaemia during surgical procedures or in intensive care medicine is one of the most important tasks of an anesthesiologist or intensive care specialist. A protocol-guided optimization of select hemodynamic parameters, in the sense of a goal-directed-therapy (GDT), has led to an improvement of the patient outcome in diverse perioperative settings. Patients who receive a transfemoral or transapical aortic valve replacement (TAVR) are mostly older and multi-morbid, for whom open surgical valve replacement (SAVR) is not indicated because of significant risks. For this cohort in particular, optimization of volume status is of special importance, although the applicability and meaningfulness of GDT has not yet been demonstrated. 40 patients undergoing TAVR stroke volume (SV) and stroke volume variation (SVV) were repeatedly measured pre- and intraoperatively and SV was optimized through an intravenous dose of 250ml colloids (6 % HES 130/0,4) (intervention group). This group was retrospectively compared with 40 TAVR patients, who were treated before implementing GDT. The primary outcome was the occurrence of at least one postoperative complication, defined as delirium, postoperative infection, postoperative bleeding, acute renal failure, cardiac or pulmonary complications. GDT led to a significant increase in SV after the induction of anaesthesia in the intervention group (SV after induction 60 [42 ; 67] vs SV after optimization 70 [58 ; 92], p=0,003). According to protocol, patients of the intervention group received significantly more colloidal (750 [500; 1000] vs. 500 [0; 500], p<0,001), and less crystalloid (500 [0; 500 vs. 500 [500; 1000], p<0,001) infusions. However, the overall fluid loading did not diverge. Patients in the intervention group had a lower rate of postoperative delirium than those in the control group (17 vs 6, p=0,006). Thus, the protocol was used successfully for the perioperative optimization of SV. The optimization of SV was associated with a lower rate of postoperative delirium. Prospective randomized studies with patient numbers powered for these outcomes and a longer follow-up will be necessary to confirm the efficiency of this strategy