The Burden of Viruses in Pneumonia Associated With Acute Respiratory Failure: An Underappreciated Issue. (Freeman)

Shorr AF, et al. The Burden of Viruses in Pneumonia Associated With Acute Respiratory Failure: An Underappreciated Issue. Chest. 2018 Jul; 154(1):84-90.

BACKGROUND: Pneumonia associated with mechanical ventilation (MV) results in substantial mortality and represents a leading reason for the use of antibiotics. The role of viruses in this setting is unclear. Identifying a viral cause in such instances could facilitate antibiotic stewardship.

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Albuterol administration is commonly associated with increases in serum lactate in asthmatics treated for acute exacerbation of asthma. (Fortenberry)

Lewis LM, Ferguson I, House SL, Aubuchon K, Schneider J, Johnson K, Matsuda K. Albuterol administration is commonly associated with increases in serum lactate in asthmatics treated for acute exacerbation of asthma. Chest. 2014 Jan; 145(1): 53–59.

BACKGROUND: Controversy exists surrounding the incidence and cause of hyperlactatemia during asthma exacerbations. We evaluate incidence, potential causes, and adverse events of hyperlactatemia in patients with acute asthma exacerbation.

METHODS: Sub-analysis of placebo subjects from a prospective, randomized trial evaluating an intravenous beta-adrenergic agonist in acute asthma exacerbation ( identifier NCT00683449).Subjects had plasma albuterol, serum lactate and bicarbonate concentrations measured at baseline and 1.25 hours as well as dyspnea score and spirometry measured at baseline and hourly for 3 hours. All subjects had a therapeutic trial consisting of 5-15 mg of nebulized albuterol, 0.5-1 mg of nebulized ipratropium, and at least 50 mg of oral prednisone, or its equivalent prior to initiation of the study. Following randomization, subjects were treated with continued albuterol and intravenous magnesium at the discretion of their treating physician. Subjects were followed to admission or discharge with follow up at 24 hours and 1 week.

Results: 175 subjects were enrolled in the parent trial, 84 in the placebo group. 65 had complete data. Mean albuterol administration prior to baseline was 12.3mg (SD±5.3).Mean baseline lactate was 18.5mg/dL (SD±8.4) vs. 26.5mg/dL (SD±11.8) at 1.25 hours; p>0.001. 45 subjects (69.2%) had hyperlactatemia. Mean baseline bicarbonate was 22.6mEq/L (SD±2.9) vs. 21.9mEq/L (SD±4.0) at 1.25 hours; p=0.11.Plasma albuterol concentration correlated to lactate concentration (β coefficient=0.45; p<0.001), and maintained significant association after adjusting for asthma severity (β=0.41; p=0.001). Hyperlactatemia did not increase the risk of hospitalization/relapse (p=0.26), nor was it associated with lower %FEV1 at 3 hours (p=0.54).

CONCLUSION: Plasma albuterol was significantly correlated with serum lactate concentration, after adjusting for asthma severity. Hyperlactatemia was not associated with poorer pulmonary function as measured by 3-hour %FEV1, or increased hospitalization/relapse at one week.

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Ventilator-associated tracheobronchitis in a mixed medical/surgical pediatric intensive care unit. (Kamat)

Chest. 2013 Jan 3. doi: 10.1378/chest.12-2343. [Epub ahead of print] PMID: 23288075

BACKGROUND Adult studies have demonstrated that ventilator-associated tracheobronchitis (VAT) may be a precursor to ventilator-associated pneumonia. No published data on VAT in pediatric intensive care units (PICU) were found. The purpose of this retrospective, descriptive study is to describe the incidence, characteristics and outcomes of patients at risk for VAT and formalize a process of VAT surveillance in the PICU population.

METHODS All patients meeting criteria for VAT during 2009-2010 were reviewed and data collected on risk of mortality, index of mortality, interventions, demographic data, respiratory cultures and organisms identified.

RESULTS 645 (32.7%) patients admitted met mechanical ventilation criteria with 22 (3.4%) meeting criteria for VAT. VAT patients experienced a significantly longer mean PICU length of stay (27.6 days + 22.043 vs. 6.61 days + 7.27; p= 0.000) and higher mean total ventilator time in hours (519.31 + 457.60 hours vs. 95.60 + 138.83 hours; p = 0.000). There is a significant association between tracheostomy and VAT (p=0.000) and between chronic ventilator dependence and VAT (p=0.002). Gram negative rods accounted for 71%; staphylococcal or streptococcal species were identified as 26% of causative pathogens. Six of 25 (24%) VAT events identified two or more potentially causative pathogens; four of these (67%) were in patients with a tracheostomy.

CONCLUSION VAT occurred less frequently than reported in adult studies and no cases of VAT progressed to VAP in our population. Our results suggest that VAT is a clinically significant HAI in the PICU population.

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Trendelenburg position does not increase cross-Sectional area of the internal jugular vein predictably. (Kamat)

Chest. 2013 Feb 7. doi: 10.1378/chest.11-2462. [Epub ahead of print] PMID: 23392444

BACKGROUND: The Trendelenburg position is used to distend the central veins, improving both success and safety of vascular cannulation. The purpose of this study was to measure the cross-sectional area (CSA) of the internal jugular vein (IJV) in three different positions using surface ultrasound.

METHODS: Fifty one subjects were enrolled. A Sonosite Titan 180 or M-Turbo portable ultrasound machine with a 10.5 mHz broadband linear surface probe was used. We measured the CSA of the IJV (at end-expiration at the level of the cricoid cartilage) in three positions: 15 degrees reverse Trendelenburg, supine, and 15 degrees Trendelenburg.

RESULTS: The mean CSA at 15 degrees reverse Trendelenburg was 0.83 cm2 (Std Dev 0.86), in the supine position it was 1.25 cm2 (Std Dev 0.98) and at minus 15 degrees Trendelenburg it was 1.47 cm2 (Std Dev 1.03). Moving from reverse Trendelenburg to supine, CSA increased 50 percent. In contrast, lowering the head to a Trendelenburg position increased mean CSA only 17 percent. Surprisingly, Trendelenburg positioning reduced CSA in 9 of 51 subjects.

CONCLUSIONS: Trendelenburg positioning augments CSA only modestly, on average, compared with the supine position, and in some patients reduces the CSA. TRIAL REGISTRATION: Identifier: NCT01099254.

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