Usefulness of differential time to positivity between catheter and peripheral blood cultures for diagnosing catheter-related bloodstream infection: Data analysis from routine clinical practice in the intensive care unit.

PURPOSE: To assess the accuracy of differential time to positivity (DTP) method for the diagnosis of catheter-related bloodstream infections (CRBSI) in the routine practice of our intensive care unit (ICU). MATERIALS AND METHODS: Over a five-year study period, ICU patients with a central venous catheter in place for ≥48 h and undergoing DTP test with catheter tip culture were analyzed. We investigated: the accuracy of DTP test with the usual threshold of 120 min in confirming the clinical suspicion of CRBSI; the most accurate threshold value of DTP to detect CRBSI; the diagnostic accuracy of the ratio (rather than the difference) between times to positivity. RESULTS: Among 278 episodes of paired blood cultures, 13% were CRBSIs. DTP value ≥120 min used for the diagnosis of CRBSI yielded 41% sensitivity and 74% specificity. Performance of DTP values in predicting CRBSI was low (AUC = 0.60 [95%CI: 0.48-0.72]). Cutoff value of the ratio between times to positivity was 0.80, with 46% sensitivity and 79% specificity. CONCLUSIONS: The routine use of the DTP method at any cutoff point has inadequate accuracy in detecting CRBSI in the real every day clinical practice. Not even the ratio between times to positivity seems to be clinically useful.

Lung ultrasound predicts non-invasive ventilation outcome in COVID-19 acute respiratory failure: a pilot study.

BACKGROUND: The aim of this study is to determine relationships between lung aeration assessed by lung ultrasound (LUS) with non-invasive ventilation (NIMV) outcome, intensive care unit (ICU) admission and mechanical ventilation (MV) needs in COVID-19 respiratory failure. METHODS: A cohort of adult patients with COVID-19 respiratory failure underwent LUS during initial assessment. A simplified LUS protocol consisting in scanning six areas, three for each side, was adopted. A score from 0 to 3 was assigned to each area. Comprehensive LUS score (LUSsc) was calculated as the sum of the score in all areas. LUSsc, the amount of involved sonographic lung areas (LUSq), the number of lung quadrants radiographically infiltrated and the degree of oxygenation impairment at admission (SpO2/FiO2 ratio) were compared to NIMV Outcome, MV needs and ICU admission. RESULTS: Among 85 patients prospectively included in the analysis, 49 of 61 needed MV. LUSsc and LUSq were higher in patients who required MV (median 12 [IQR 8-14] and median 6 [IQR 4-6], respectively) than in those who did not (6 [IQR 2-9] and 3 [IQR 1-5], respectively), both P<0.001. NIMV trial failed in 26 patients out 36. LUSsc and LUSq were significantly higher in patients who failed NIMV than in those who did not. From ROC analysis, LUSsc ≥12 and LUSq ≥5 gave the best cut-off values for NIMV failure prediction (AUC=0.95, 95%CI 0.83-0.99 and AUC=0.81, 95% CI 0.65-0.91, respectively). CONCLUSIONS: Our data suggest LUS as a possible tool for identifying patients who are likely to require MV and ICU admission or to fail a NIMV trial.

Microbiologic surveillance through subglottic secretion cultures during invasive mechanical ventilation: a prospective observational study.

PURPOSE: Whether subglottic secretions (SS) culture during invasive mechanical ventilation may aid microbiological surveillance is unknown. We conducted a prospective study to assess SS cultures predictivity of endotracheal aspirate (ETA) and bronchoalveolar lavage (BAL) isolates. MATERIALS AND METHODS: 109 patients receiving mechanical ventilation for ≥48 hours underwent SS and ETA surveillance cultures twice weekly; blind BAL was performed in case of clinically suspected pneumonia. RESULTS: SS and ETA cultures were fully concordant in 170 (81%-overall accuracy) of 211 sample pairs. As compared to ETA, SS culture global sensitivity and specificity were 84% [95%CI: 77 to 91] and 74% [95%CI: 66 to 82]; negative and positive predictive values were 82% and 77%. Forty-four episodes of clinically suspected pneumonia were observed. Compared to BAL, SS culture global sensitivity and specificity were 68% [95%CI: 45 to 81] and 63% [95%CI: 44 to 82]; negative and positive predictive values were both 65%. SS sensitivity, specificity, positive and negative predictive values in anticipating BAL isolates were comparable to ETA (all p > 0.20). CONCLUSIONS: SS cultures show worthy accuracy in identifying ETA isolates, with excellent sensitivity and good negative predictivity. SS cultures may be not inferior to ETA in predicting BAL results in case of ventilator-associated pneumonia. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03153241. Registered on 15 May 2017, https://clinicaltrials.gov/ct2/show/NCT03153241.

Effects of Thyroid Hormone Treatment on Diaphragmatic Efficiency in Mechanically Ventilated Subjects With Nonthyroidal Illness Syndrome.

BACKGROUND: Several respiratory abnormalities can be present in primary hypothyroidism and can be reversed with adequate hormone treatment. However, the role of thyroid hormone replacement therapy on the respiratory system in patients with nonthyroidal illness syndrome is still unclear. This physiologic study evaluated the effect of thyroid hormone treatment on respiratory muscle function in subjects with nonthyroidal illness syndrome and while on mechanical ventilation. The primary end point was neuromechanical efficiency, which provides an estimate of the efficiency of diaphragmatic contraction. Secondary end points were the transdiaphragmatic pressure-time product and the swing of the electrical activity of the diaphragm, which reflect the work of breathing and inspiratory effort, respectively. METHODS: Fifteen subjects on mechanical ventilation for ≥48 h and with a diagnosis of nonthyroidal illness syndrome who had a failed spontaneous breathing trial, received intravenous triiodothyronine. The hormone was administered as an intravenous bolus of 0.4 µg/kg triiodothyronine, followed by continuous perfusion at 0.6 µg/kg for 24 h. Neuromechanical efficiency was calculated as the ratio between the drop in airway pressure during an expiratory occlusion and the corresponding electrical activity of the diaphragm peak. Recordings were taken at baseline and after 3, 6, and 24 h. RESULTS: After study completion, free triiodothyronine serum concentrations increased in all the subjects (mean ± SD increase, 0.84 ± 0.34 pg/mL). Neuromechanical efficiency showed no significant changes throughout the study (mean ± SD baseline, 1.40 ± 0.87 cm H2O/µV; 3 h, 1.28 ± 0.64 cm H2O/µV; 6 h, 1.33 ± 0.87 cm H2O/µV; 24 h, 1.41 ± 0.96 cm H2O/µV). Similarly, no variations in transdiaphragmatic pressure-time product per min (mean ± SD baseline, 238.1 ± 124 cm H2O × s/min; 3 h, 242.5 ± 140.3 cm H2O × s /min; 6 h, 247.5 ± 161.7 cm H2O × s/min; 24 h, 281.2 ± 201.2 cm H2O × s/min) or swing of electrical activity of the diaphragm (mean ± baseline, 20.9 ± 13.1 µV; 3 h, 17.2 ± 8.3 µV; 6 h, 17.4 ± 11.3 µV; 24 h, 20.3 ± 13.7 µV) were observed during hormone administration. CONCLUSIONS: In the subjects on mechanical ventilation who were admitted to the ICU with nonthyroidal illness syndrome, thyroid hormone replacement treatment did not yield any benefit on respiratory muscle function when assessed by neuromechanical efficiency, which indicated that, in these subjects restoring normal levels of serum thyroid hormones is debatable. (ClinicalTrials.gov registration NCT03157466.).

Prognostic value of the reactive oxygen species in severe sepsis and septic shock patients: a pilot study.

BACKGROUND: Reactive oxygen species (ROS) have been shown to play a role in the pathophysiology of sepsis. The aim of this study was to investigate ROS production over time in critically ill with sepsis patients and its correlation with outcome. METHODS: This was a pilot single-centre prospective, observational study of patients consecutively admitted to our 18-general ICU. Over a period of 6 months all the consecutive patients with recent-onset of severe sepsis or septic shock were enrolled. Clinical and demographic characteristics of all patients were recorded. ROMs (ROS metabolites), reduced sulfhydryl groups (SH) and plasmatic lactate levels were collected at enrollment in the study and then every 5-7 days over 28 days or until sepsis resolution or death during sepsis. ROMs were analysed spectrophotometrically by the d-ROMs test (Diacron-Italia). SH were assayed in plasma by Ellman's reaction by spectrophotometric method. Septic shock-related mortality was defined as death that occurred during the follow up period, when the signs of shock remained, and death could not be attributed to causes other than septic shock by the attending physician. RESULTS: Twenty-five patients were studied. The SOFA score and the plasmatic lactate levels significantly correlated with the ROMs plasmatic levels. The mortality rate was higher in patients whose ROMs plasmatic levels decreased during septic shock evolution. CONCLUSIONS: Serial measurements of the ROMs plasmatic levels together with the SOFA score and lactate levels could help to identify septic shock patients with a very high probability of death.

Comparison of two methods to assess blood CO2 equilibration curve in mechanically ventilated patients.

In order to compare two mathematical methods to assess the blood CO2 equilibration curve from a single blood gas analysis [Loeppky, J.A., Luft, U.C., Fletcher, E.R., 1983. Quantitative description of whole blood CO2 dissociation curve and Haldane effect. Resp. Physiol. 51, 167-181; Giovannini, I., Chiarla, C., Boldrini, G., Castagneto, M., 1993. Calculation of venoarterial CO2 concentration difference. J. Appl. Physiol. 74, 959-964], arterial and central venous blood gas analyses and oximetry were performed before and after ventilatory resetting, at constant arterial O2 saturation, in 12 mechanically ventilated patients. CO2 equilibration curves obtained from basal arterial blood gas analyses were used to predict arterial CO2 content after ventilatory resetting and vice versa. Internal consistency was very good for both methods and comparable. Method 2 also yielded excellent predictions of changes of arterial pH associated with ventilatory resetting. In determining Haldane effect, method 2 yielded very stable results within the expected range of values, while method 1 yielded a wider spread of results. Method 2 appeared more suitable to determine the Haldane effect in the conditions of the study, probably due to an approach minimizing the effect of potential sources of inaccuracy.

Injury of the vertebral artery after closed head trauma.

Two case reports characterized by the complete occlusion of the basilar artery, secondary to dissection of the vertebral artery after closed head trauma are described. These lesions, often clinically silent in the beginning, were able to cause severe neurologic impairment, even after minor head trauma in healthy individuals without predisposing structural disorders. Early detection, based upon the knowledge of the modality of the trauma and upon a correct diagnostic approach, is mandatory to reduce secondary injury. The authors suggest an extensive use of cerebral angiography or angio-magnetic resonance in all cases where clinical conditions are more severe than the computed tomography scan, particularly if the trauma produced a cervical injury with a movement of flexo-extension of the neck. Therapeutic management is discussed. Anti-coagulants, thrombolytic agents or surgical ligation of the vessel has been proposed to prevent the extension of the lesion and to improve the outcome.