Daily Respiratory Research Analysis

BACKGROUND: Arterial blood gas analysis (ABGA) is the reference standard for the diagnosis of respiratory failure (RF) and metabolic disturbance (MD), but peripheral venous blood gas analysis (PVBGA) is increasingly being used for the estimation of carbon dioxide, pH, and other variables in the context of acutely unwell adults presenting to hospitals and emergency departments. OBJECTIVES: The primary objective of this review is to evaluate the performance of PVBGA by comparing it with the reference standard ABGA, which is assumed to be error-free for the diagnosis of (1) respiratory failure, (2) hypercarbia, and (3) metabolic disturbance (the three target conditions) in adults. The secondary objective is to evaluate the performance of the index test to diagnose nine specific subtypes of respiratory failure and metabolic disturbance. The definitions for these additional conditions are determined by changes to one or more of the following: pH (acidity), pO SEARCH METHODS: On 10 July 2024, we searched the electronic databases MEDLINE, EMBASE, CINAHL, and LILACS. We also manually searched 19 respiratory and critical care journals, and we searched ClinicalTrials.gov for ongoing trials. SELECTION CRITERIA: We considered consecutive series studies and case-control studies that directly compared the index test PVBGA to the reference standard ABGA for adults over the age of 16 years. The included studies contained data for any one of the target conditions of respiratory failure and metabolic disturbance, as determined by individual changes to pO DATA COLLECTION AND ANALYSIS: Two authors independently evaluated the quality of the relevant studies and extracted data from them. We conducted a quality assessment using the QUADAS-2 tool. Our statistical analysis used 2 x 2 tables for the positive and negative results of each test. We estimated a bivariate meta-analysis of sensitivity and specificity. MAIN RESULTS: We included six studies (919 participants) in our quantitative analysis. All studies were at high risk of bias due to one or more of the following factors: patient selection, since it was unclear if consecutive patients were included or where they were located; index test, with poor reporting of cut-offs; flow and timing domain because the fraction of inspired oxygen was frequently not stated and any difference between the collection of the VBGA and the ABGA could introduce bias. Respiratory failure For the diagnosis of respiratory failure of any type, when using PVBGA, the estimated summary sensitivity (Sn) was 97.6% (95% credible interval (CI) 94.1 to 99.4) and the estimated summary specificity (Sp) was 36.9% (95% CI 17.1 to 60.1) (6 studies, 805 participants of whom 291 (36%) were diagnosed with respiratory failure by ABGA; sensitivity: low-certainty evidence; specificity: very low certainty evidence). Isolated hypercarbia For the diagnosis of isolated hypercarbia (regardless of oxygen level), when using PVBGA, the estimated summary Sn was 97.1% (95% CI 93.3 to 99.2); the estimated summary Sp value was 53.9% (95% CI 39.8 to 66.7) (6 studies with 805 participants, 269 (33%) with ABGA confirmation; low-certainty evidence). Other findings Results for metabolic disturbance and our secondary target conditions are presented in the full review. AUTHORS' CONCLUSIONS: Very limited data suggest PVBGA performs poorly as a diagnostic test for respiratory failure compared to the reference standard of ABGA. The index test PVBGA was highly sensitive for the diagnosis of respiratory failure and isolated hypercarbia, but its specificity was poor for these two primary target conditions. The high sensitivity means PVBGA may have a useful role as a "rule out test" for respiratory failure and isolated hypercarbia; however, the high false-positive rates make the clinical interpretation of a positive test difficult. Moreover, we are uncertain regarding these estimates because we have only low to very low certainty about the evidence. Further studies that use (ABGA) established thresholds for the diagnosis of each target condition are needed.

IMPORTANCE: SARS-CoV-2 continues to evolve, population immunity changes, and COVID-19 vaccine formulas have been updated, necessitating ongoing COVID-19 vaccine effectiveness (VE) monitoring. OBJECTIVES: To evaluate the VE of 2023-2024 COVID-19 vaccines against COVID-19-associated emergency department (ED) and urgent care (UC) encounters, hospitalizations, and critical illness, including during XBB- and JN.1-predominant periods. DESIGN, SETTING, AND PARTICIPANTS: This test-negative design VE case-control study was conducted using data from September 21, 2023, to August 22, 2024, from EDs, UC centers, and hospitals in 6 US health care systems. Eligible adults 18 years or older with COVID-19-like illness and molecular or antigen testing for SARS-CoV-2 were studied. Case patients were those with a positive molecular or antigen test result; control patients were those with a negative molecular test result. EXPOSURE: Receipt of 2023-2024 (monovalent XBB.1.5) COVID-19 vaccination with products approved or authorized for use in the US. MAIN OUTCOMES AND MEASURES: Main outcomes were COVID-19-associated ED and UC encounters, hospitalizations, and critical illness (admission to the intensive care unit or in-hospital death). VE was estimated comparing the odds of receipt of the 2023-2024 COVID-19 vaccine with no receipt among case and control patients. RESULTS: Among 345 639 eligible ED and UC encounters in immunocompetent adults 18 years or older with COVID-19-like illness and available test results (median [IQR] age, 53 [34-71] years; 209 087 [60%] female), 37 096 (11%) had a positive SARS-CoV-2 test result. VE against COVID-19-associated ED and UC encounters was 24% (95% CI, 21%-26%) during 7 to 299 days after vaccination. Among 111 931 eligible hospitalizations in immunocompetent adults 18 years or older with COVID-19-like illness and available test results (median [IQR] age, 71 [58-81] years), 10 380 (9%) had a positive SARS-CoV-2 test result. During 7 to 299 days after vaccination, VE was 29% (95% CI, 25%-33%) against COVID-19-associated hospitalization and 48% (95% CI, 40%-55%) against COVID-19-associated critical illness. VE was highest 7 to 59 days after vaccination (VE against ED and UC encounters 49%; 95% CI, 46%-52%; hospitalization, 51%; 95% CI, 46%-56%; critical illness, 68%; 95% CI, 56%-76%) and then waned (VE 180-299 days after vaccination against ED and UC encounters, -7% [95% CI, -13% to -2%]; hospitalization, -4% [95% CI, -14% to 5%]; and critical illness, 16% [95% CI, -6 to 34%]). CONCLUSIONS AND RELEVANCE: In this case-control study of VE, 2023-2024 COVID-19 vaccines were estimated to provide additional effectiveness against medically attended COVID-19, with the highest and most sustained estimates against critical illness. These results highlight the importance of receiving recommended COVID-19 vaccination for adults 18 years or older.

BACKGROUND: Oscillometry may provide the feasible and sensitive tool for objective remote monitoring of paediatric asthma. METHODS: Observational study of school-aged healthy, well-controlled and poorly-controlled asthma performing daily home-based oscillometry for 3-4 months, alongside objective measures of asthma control (Asthma Control Questionnaire weekly and Asthma Control Test monthly), medication use and exacerbations. Day-to-day variability calculated as coefficient of variation (CV) for resistance at 5 Hz (R5), reactance at 5 Hz (X5) and area under reactance curve (AX). Our objective was to examine feasibility, whether day-to-day variability was increased in asthma and correlations with asthma control and exacerbation burden. Clinical exacerbation patterns were examined using principal component analysis and k-means clustering of oscillometry, symptoms, breathing parameters and adherence. RESULTS: Feasibility was 74.9±16.0% in health (n=13, 93.7±16.2 days) and 80.6±12.9% in asthma (n=42, 101.6±24.9 days; 17 well-controlled and 27 poorly-controlled asthma). Increased day-to-day variability in all oscillometry indices occurred in asthma versus health (all p≤0.002), with CV R5 the best discriminator (area under receiver operating characteristics curve 0.88, p<0.001). CV R5 increased during exacerbation and correlated with all asthma control measures and exacerbation burden. Correlations remained when examining non-exacerbation oscillometry data. Two exacerbation patterns were found based on oscillometry data in the pre-exacerbation period, characterised by severity of impairment of R5, X5, AX and CV R5 (n=12, more severe). Findings were similar using post-exacerbation period oscillometry data (n=8, more severe). Symptoms did not differ across exacerbation patterns. CONCLUSIONS: Home-based oscillometry monitoring was highly feasible over extended periods in school-aged asthmatics. Day-to-day oscillometry variability was increased in asthma compared with health, reflected asthma control and exacerbation burden and identified differing exacerbation patterns.