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. 2022 Jan 3;22(1):16.
doi: 10.1186/s12887-021-03087-z.

Variability of respiratory rate measurements in neonates- every minute counts

Catherine Muthoni Njeru  1 , J Mark Ansermino  2 , William M Macharia  3 , Dustin T Dunsmuir  2
Affiliations

Variability of respiratory rate measurements in neonates- every minute counts

Catherine Muthoni Njeru et al. BMC Pediatr. .

Abstract

Background: Respiratory rate is difficult to measure, especially in neonates who have an irregular breathing pattern. The World Health Organisation recommends a one-minute count, but there is limited data to support this length of observation. We sought to evaluate agreement between the respiratory rate (RR) derived from capnography in neonates, over 15 s, 30 s, 120 s and 300 s, against the recommended 60 s.

Methods: Neonates at two hospitals in Nairobi were recruited and had capnograph waveforms recorded using the Masimo Rad 97. A single high quality 5 min epoch was randomly chosen from each subject. For each selected epoch, the mean RR was calculated using a breath-detection algorithm applied to the waveform. The RR in the first 60 s was compared to the mean RR measured over the first 15 s, 30 s, 120 s, full 300 s, and last 60 s. We calculated bias and limits of agreement for each comparison and used Bland-Altman plots for visual comparisons.

Results: A total of 306 capnographs were analysed from individual subjects. The subjects had a median gestation age of 39 weeks with slightly more females (52.3%) than males (47.7%). The majority of the population were term neonates (70.1%) with 39 (12.8%) having a primary respiratory pathology. There was poor agreement between all the comparisons based on the limits of agreement [confidence interval], ranging between 11.9 [- 6.79 to 6.23] breaths per minute in the one versus 2 min comparison, and 34.7 [- 17.59 to 20.53] breaths per minute in the first versus last minute comparison. Worsening agreement was observed in plots with higher RRs.

Conclusions: Neonates have high variability of RR, even over a short period of time. A slight degradation in the agreement is noted over periods shorter than 1 min. However, this is smaller than observations done 3 min apart in the same subject. Longer periods of observation also reduce agreement. For device developers, precise synchronization is needed when comparing devices to reduce the impact of RR variation. For clinicians, where possible, continuous or repeated monitoring of neonates would be preferable to one time RR measurements.

Keywords: Neonates; Respiratory rate measurement; Variability.

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Conflict of interest statement

There are no conflicts of interest to declare.

Figures

Fig. 1
Fig. 1
Bland Altman Plots (A to E) comparing RR values of different time periods
Fig. 2
Fig. 2
Plot showing the bias and spread of limits of agreement from different durations of observations with normalized RR values expressed as percentages on the right
See this image and copyright information in PMC

References

    1. Lovett PB, Buchwald JM, Stürmann K, Bijur P. The vexatious vital: neither clinical measurements by nurses nor an electronic monitor provides accurate measurements of respiratory rate in triage. Ann Emerg Med. 2005;45(1):68–76. doi: 10.1016/j.annemergmed.2004.06.016. - DOI - PubMed
    1. Curzi-Dascalova L, Gaudebout C, Dreyfus-Brisac C. Respiratory frequencies of sleeping infants during the first months of life: correlations between values in different sleep states. Early Hum Dev. 1981;5(1):39–54. doi: 10.1016/0378-3782(81)90069-4. - DOI - PubMed
    1. MacLean JE, Fitzgerald DA, Waters KA. Developmental changes in sleep and breathing across infancy and childhood. Paediatr Respir Rev. 2015;16(4):276–284. doi: 10.1016/j.prrv.2015.08.002. - DOI - PubMed
    1. World Health Organization (WHO) Fourth Programme Report, 1988-1989: ARI Programme for Control of Acute Respiratory Infections. 1990.
    1. Health MOF. Integrated management of newborn & childhood ILLNESSES ( IMNCI ) A guide for healthcare workers. 2018.

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