{
  "abstract": "Introduction Current ARTP guidelines recommend that Peak Expiratory Flow (PEF) variability between manoeuvres should be within 40 L.min-1 for acceptability. However, this is largely based on a study by Pederson et al. (1996) which mostly included healthy individuals. Moreover, the original study was not designed to inform spirometry guidelines, and no formal evidence defines an acceptable level of PEF variation. Therefore, this study aims to explore the impact of variable PEF on the reproducibility of FEV1 in a cohort with diverse respiratory conditions.Methodology We analysed 22,071 spirometry manoeuvres from 4,913 patients (55% male; median age 64 [53–74] 92% Caucasian) tested at Royal Papworth Hospital NHS FT in 2023. To assess the impact of PEF variability on FEV1, manoeuvres performed during the same session and compliant with ATS/ERS 2017 standards were compared to a reference manoeuvre with the highest PEF. Data distribution was evaluated using histograms, and the effects of PEF variation on FEV1 were visualised with box plots. Patients were stratified into those with airflow obstruction (FEV1/FVC < LLN) and those without (FEV1/FVC ≥ LLN). FEV1 difference (ml) was calculated across five PEF categories, (< 40 L.min-1 to > 200 L.min-1) and compared using the Friedman test.Results There was a significant difference in FEV1 across all PEF categories (p < 0.001), with FEV1 increasing as PEF difference increased. This trend was more pronounced in obstructed patients ( figure 1).Abstract P6 Figure 1Compares the effect of PEF difference on FEV1 in both obstructed and non- obstructed patients. The median values are reflected on top of each boxplotConclusion This study demonstrates that PEF reproducibility is directly related to FEV1 reproducibility, especially in patients with airflow obstruction. Our results support the current ARTP criteria that the PEF of acceptable spirometry manoeuvres should be within 40 L.min-1 of each other. Larger variation can result in over 25% of manoeuvres having an FEV1 difference >150 ml. Further research is required to determine the effect on disease severity and classification.",
  "authors": [
    {
      "affiliations": [
        "Royal Papworth Hospital NHS Ft, Cambridge, UK"
      ],
      "name": "Abdul-Rasaq Yakubu"
    },
    {
      "affiliations": [
        "Royal Papworth Hospital NHS Ft, Cambridge, UK"
      ],
      "name": "Jake Williams"
    },
    {
      "affiliations": [
        "Royal Papworth Hospital NHS Ft, Cambridge, UK"
      ],
      "name": "Benjamin Knox-Brown"
    },
    {
      "affiliations": [
        "Royal Papworth Hospital NHS Ft, Cambridge, UK"
      ],
      "name": "Joshua Barnes"
    },
    {
      "affiliations": [
        "Royal Papworth Hospital NHS Ft, Cambridge, UK"
      ],
      "name": "Karl Sylvester"
    }
  ],
  "title": "P6 The impact of peak expiratory flow variability on the forced expiratory volume in 1 second",
  "uid": "21a4d1aa-c6fb-5732-b571-9f37592cb377"
}