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. 2021 Dec 10;8(1):e001042. doi: 10.1136/bmjresp-2021-001042

Figure 4.

Figure 4

Interbreath intervals are altered by morphine administration and following ROP screening. (A–D) Respiratory rate and interbreath intervals (IBIs) in the 1-hour period prior to morphine administration compared with a 1-hour period after morphine administration (the 1-hour period immediately following ROP screening, approximately 1.3–2.3 hours after morphine administration) in the 15 infants who received morphine in the Poppi clinical trial. (E–H) Respiratory rate and IBIs 1 hour before and after ROP screening in 22 infants. (A, E) Mean respiratory rate from the infants’ patient monitor. (B–D, F–H) Metrics calculated using the novel algorithm proposed in this paper to identify the IBIs. Black lines and points indicate the group mean (A, C, E, F) or median (D, H). (B) IBI distribution in the 1-hour period prior to (black) compared with 1.3–2.3 hours after morphine administration (red). (F) IBI distribution in the 1-hour period before (black) and after (red) ROP screening. Y-axis indicates the probability of an IBI of duration greater than or equal to the X-axis value. Dotted line indicates the mean and shaded area the SD. (*p<0.05, **p<0.01, ***p<0.001, p-values corrected for multiple comparisons). ROP, retinopathy of prematurity.