Hospital-Acquired Infections in Critically Ill Patients With COVID-19

Background: Few small studies have described hospital-acquired infections (HAIs) occurring in patients with COVID-19. Research Question: What characteristics in critically ill patients with COVID-19 are associated with HAIs and how are HAIs associated with outcomes in these patients? Study Design and Methods: Multicenter retrospective analysis of prospectively collected data including adult patients with severe COVID-19 admitted to eight Italian hub hospitals from February 20, 2020, through May 20, 2020. Descriptive statistics and univariate and multivariate Weibull regression models were used to assess incidence, microbial cause, resistance patterns, risk factors (ie, demographics, comorbidities, exposure to medication), and impact on outcomes (ie, ICU discharge, length of ICU and hospital stays, and duration of mechanical ventilation) of microbiologically confirmed HAIs. Results: Of the 774 included patients, 359 patients (46%) demonstrated 759 HAIs (44.7 infections/1,000 ICU patient-days; 35% multidrug-resistant [MDR] bacteria). Ventilator-associated pneumonia (VAP; n = 389 [50%]), bloodstream infections (BSIs; n = 183 [34%]), and catheter-related BSIs (n = 74 [10%]) were the most frequent HAIs, with 26.0 (95% CI, 23.6-28.8) VAPs per 1,000 intubation-days, 11.7 (95% CI, 10.1-13.5) BSIs per 1,000 ICU patient-days, and 4.7 (95% CI, 3.8-5.9) catheter-related BSIs per 1,000 ICU patient-days. Gram-negative bacteria (especially Enterobacterales) and Staphylococcus aureus caused 64% and 28% of cases of VAP, respectively. Variables independently associated with infection were age, positive end expiratory pressure, and treatment with broad-spectrum antibiotics at admission. Two hundred thirty-four patients (30%) died in the ICU (15.3 deaths/1,000 ICU patient-days). Patients with HAIs complicated by septic shock showed an almost doubled mortality rate (52% vs 29%), whereas noncomplicated infections did not affect mortality. HAIs prolonged mechanical ventilation (median, 24 days [interquartile range (IQR), 14-39 days] vs 9 days [IQR, 5-13 days]; P < .001), ICU stay (24 days [IQR, 16-41 days] vs 9 days [IQR, 6-14 days]; P = .003), and hospital stay (42 days [IQR, 25-59 days] vs 23 days [IQR, 13-34 days]; P < .001). Interpretation: Critically ill patients with COVID-19 are at high risk for HAIs, especially VAPs and BSIs resulting from MDR organisms. HAIs prolong mechanical ventilation and hospitalization, and HAIs complicated by septic shock almost double mortality. Trial Registry: ClinicalTrials.gov; No.: NCT04388670; URL: www.clinicaltrials.go

Spatial orientation and mechanical properties of the human trachea : a computed tomography study

BACKGROUND: The literature generally describes the trachea as oriented toward the right and back, but there is very little detailed characterization. Therefore, the aim of this study was to precisely determine the spatial orientation and to better characterize the physical properties of the human trachea. METHODS: We analyzed lung computed tomography scans of 68 intubated and mechanically ventilated subjects suffering from acute lung injury/ARDS at airway pressures (Paw) of 5, 15, and 45 cm H2O. At each Paw, the inner edge of the trachea from the subglottal space to the carina was captured. Tracheal length and diameter were measured. Tracheal orientation and compliance were estimated from processing barycenter and surface tracheal sections. RESULTS: Tracheal orientation at a Paw of 5 cmH2O showed a 4.2_5.3\ub0 angle toward the right and a 20.6_6.9\ub0 angle downward toward the back, which decreased significantly while increasing Paw (19.4_6.9\ub0 at 15 cm H2O and 17.1_6.8\ub0 at 45 cm H2O, P < .001). Tracheal compliance was 0.0113_0.0131 mL/cm H2O/cm of trachea length from 5 to 15 cm H2O and 0.004_0.0041 mL/cm H2O/cm of trachea length from 15 to 45 cm H2O (P < .001). Tracheal diameter was 19.6_3.4 mm on the medial-lateral axis and 21.0_4.3 mm on the sternal-vertebral axis. CONCLUSIONS: The trachea is oriented downward toward the back at a 20.6_6.9\ub0 angle and slightly toward the right at a 4.2_5.3\ub0 angle. Understanding tracheal orientation may help in enhancing postural drainage and respiratory physiotherapy, and knowing the physical properties of the trachea may aid in endotracheal tube cuff design

Orientation and mechanical properties of human trachea : a CT scan study

Introduction We wished to determine orientation and mechanical properties of the human trachea. Materials and Methods We retrospectively analyzed a previously published database of 68 ALI/ARDS patients who underwent whole lung CT scan at PEEP 5, 15 and 45 cmH2O [Gattinoni, NEJM, 2006]. We manually draw the inner border of the trachea from below the glottis to the carina. Tracheal orientation was estimated computing the baricentrum of each tracheal section. Tracheal compliance and shape was measured at increasing PEEP level. The compliance was calculated as the ratio between the increase in tracheal gas volume (ml) and the increase in pressure (cmH2O). The shape was determined by the coronal and sagittal diameters measured at mid-trachea. Results We studied 84.4\ub19.6 mm of trachea length. Orientation: trachea showed a 4.1\ub15.2\ub0 angel toward left and 20.8\ub16.7\ub0 angel downward toward the back. Compliance was not linear and had a median 0.27 ml/cmH2O [IQ range 0.18 \u2013 0.39] going from PEEP 5 cmH2O to PEEP 15 cmH2O and 0.12 [IQ range 0.07 \u2013 0.18] from PEEP 15 cmH2O to PEEP 45 cmH2O. Shape: diameter on the coronal plane was not modified with PEEP (20.6\ub13.5, 20.6\ub13.4 and 20.6\ub13.3 mm at PEEP 5, 15 and 45 cmH2O, respectively) while diameter on sagittal plane increased of approximately 4% (24\ub15.2, 24.8\ub15.2 and 25\ub15.1 mm at PEEP 5, 15 and 45 cmH2O, respectively). Conclusion The exact determination of tracheal orientation, in particular the displacement on the sagittal plane, may be of interest to enhance postural drainage of secretions. The mechanical properties of the trachea may be of interest during \u201cprotective\u201d mechanical ventilation and when designing endotracheal tube cuffs

Extracorporeal CO2 removal by respiratory electrodialysis: an in vitro study

We previously described a highly efficient extracorporeal CO2 removal technique called respiratory electrodialysis (R-ED). Respiratory electrodialysis was composed of a hemodiafilter and a membrane lung (ML) positioned along the extracorporeal blood circuit, and an electrodialysis (ED) cell positioned on the hemodiafiltrate. The ED regionally increased blood chloride concentration to convert bicarbonate to CO2 upstream the ML, thus enhancing ML CO2 extraction (VCO2ML). In this in vitro study, with an aqueous polyelectrolytic carbonated solution mimicking blood, we tested a new R-ED setup, featuring an ML positioned on the hemodiafiltrate after the ED, at increasing ED current levels (0, 2, 4, 6, and 8 A). We measured VCO2ML, electrolytes concentrations, and pH of the extracorporeal circuit. Raising levels of ED-current increased chloride concentration from 107.5 \ub1 1.6 to 114.6 \ub1 1.3 mEq/L (0 vs. 8 A, p < 0.001) and reduced pH from 7.48 \ub1 0.01 to 6.51 \ub1 0.05 (0 vs. 8 A, p < 0.001) of the hemodiafiltrate entering the ML. Subsequently, VCO2ML increased from 27 \ub1 1.7 to 91.3 \ub1 1.5 ml/ min (0 vs. 8 A, p < 0.001). Respiratory electrodialysis is efficient in increasing VCO2ML of an extracorporeal circuit featuring an ML perfused by hemodiafiltrate. During R-ED, the VCO2ML can be significantly enhanced by increasing the ED current

Regional blood acidification enhances extracorporeal carbon dioxide removal

none11noBACKGROUND:: Extracorporeal carbon dioxide removal has been proposed to achieve protective ventilation in patients at risk for ventilator-induced lung injury. In an acute study, the authors previously described an extracorporeal carbon dioxide removal technique enhanced by regional extracorporeal blood acidification. The current study evaluates efficacy and feasibility of such technology applied for 48 h. METHODS:: Ten pigs were connected to a low-flow veno-venous extracorporeal circuit (blood flow rate, 0.25 l/min) including a membrane lung. Blood acidification was achieved in eight pigs by continuous infusion of 2.5 mEq/min of lactic acid at the membrane lung inlet. The acid infusion was interrupted for 1 h at the 24 and 48 h. Two control pigs did not receive acidification. At baseline and every 8 h thereafter, the authors measured blood lactate, gases, chemistry, and the amount of carbon dioxide removed by the membrane lung (VCO2ML). The authors also measured erythrocyte metabolites and selected cytokines. Histological and metalloproteinases analyses were performed on selected organs. RESULTS:: Blood acidification consistently increased VCO2ML by 62 to 78%, from 79 ± 13 to 128 ± 22 ml/min at baseline, from 60 ± 8 to 101 ± 16 ml/min at 24 h, and from 54 ± 6 to 96 ± 16 ml/min at 48 h. During regional acidification, arterial pH decreased slightly (average reduction, 0.04), whereas arterial lactate remained lower than 4 mEq/l. No sign of organ and erythrocyte damage was recorded. CONCLUSION:: Infusion of lactic acid at the membrane lung inlet consistently increased VCO2ML providing a safe removal of carbon dioxide from only 250 ml/min extracorporeal blood flow in amounts equivalent to 50% production of an adult man. Copyright © 2013, the American Society of Anesthesiologists, Inc.noneZanella, Alberto; Mangili, Paolo; Redaelli, Sara; Scaravilli, Vittorio; Giani, Marco; Ferlicca, Daniela; Scaccabarozzi, Diletta; Pirrone, Federica; Albertini, Mariangela; Patroniti, Nicolò; Pesenti, Antonio*Zanella, Alberto; Mangili, Paolo; Redaelli, Sara; Scaravilli, Vittorio; Giani, Marco; Ferlicca, Daniela; Scaccabarozzi, Diletta; Pirrone, Federica; Albertini, Mariangela; Patroniti, Nicolò; Pesenti, Antoni