Physiological abnormalities in patients admitted with acute exacerbation of COPD: an observational study with continuous monitoring

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) may rapidly require intensive care treatment. Evaluation of vital signs is necessary to detect physiological abnormalities (micro events), but patients may deteriorate between measurements. We aimed to assess if continuous monitoring of vital signs in patients admitted with AECOPD detects micro events more often than routine ward rounds. In this observational pilot study (NCT03467815), 30 adult patients admitted with AECOPD were included. Patients were continuously monitored with peripheral oxygen saturation (SpO(2)), heart rate, and respiratory rate during the first 4 days after admission. Hypoxaemic events were defined as decreased SpO(2) for at least 60 s. Non-invasive blood pressure was also measured every 15-60 min. Clinical ward staff measured vital signs as part of Early Warning Score (EWS). Data were analysed using Fisher's exact test or Wilcoxon rank sum test. Continuous monitoring detected episodes of SpO(2) < 92% in 97% versus 43% detected by conventional EWS (p < 0.0001). Events of SpO(2) < 88% was detected in 90% with continuous monitoring compared with 13% with EWS (p < 0.0001). Sixty-three percent of patients had episodes of SpO(2) < 80% recorded by continuous monitoring and 17% had events lasting longer than 10 min. No events of SpO(2) < 80% was detected by EWS. Micro events of tachycardia, tachypnoea, and bradypnoea were also more frequently detected by continuous monitoring (p < 0.02 for all). Moderate and severe episodes of desaturation and other cardiopulmonary micro events during hospitalization for AECOPD are common and most often not detected by EWS.