TY - JOUR
T1 - Use of a novel non-invasive respiratory monitor to study changes in pulmonary ventilation during labor epidural analgesia
AU - Kodali, Bhavani Shankar
AU - Choi, Lynn
AU - Chau, Anton
AU - Harvey, Brian C.
AU - Brayanov, Jordan
AU - Tsen, Lawrence C.
AU - Palanisamy, Arvind
N1 - Publisher Copyright:
© 2019, Springer Nature B.V.
PY - 2020/6/1
Y1 - 2020/6/1
N2 - Measuring continuous changes in maternal ventilation during labor neuraxial analgesia is technically difficult. Consequently, the magnitude of pulmonary minute ventilation (MV) alterations following labor analgesia remains unknown. We hypothesized that a novel, bio-impedance based non-invasive respiratory monitor would provide this information. Furthermore, we sought to determine if an association between changes in MV and maternal temperature existed. Following calibration with a Haloscale Standard Wright Respirometer, the ExSpiron respiratory volume monitor (RVM) measured MV, respiratory rate (RR), and tidal volume (TV) in 41 term parturients receiving epidural analgesia. Simultaneously, maternal oral temperatures were recorded at pre-specified hourly intervals after epidural analgesia initiation until delivery. Cumulative MV changes were calculated as the integral of MV change over time: MV (∫0TΔMVdt), where T represents the time between epidural placement and variable measurement. The association between changes in MV and cumulative MV versus maternal temperature was determined by comparing patients whose temperature did or did not increase by ≥ 0.5 °C. After initiation of epidural analgesia, MV decreased by 11.1 ± 27.6% [mean ± SD] at 30 min, p = 0.006, and 19.8 ± 26.1% at 2 h compared to baseline (12.6 ± 7.3 L/min at baseline vs. 15.3 ± 6.3 L/min at 2 h, p < 0.001), Minute ventilation remained decreased at 4 h by 14.3 ± 31.4% (p = 0.013). The cumulative MV also decreased by 437 ± 852 L [mean ± SD], p = 0.009) at 2 h and by 795 ± 1431 L, p < 0.001) at 4 h following epidural analgesia initiation, compared to baseline. The association between changes in cumulative MV and maternal temperature following epidural placement was weak (R < 0.3); however, a decrease in MV at 30 min (p = 0.002) and cumulative MV at 2 h (p = 0.012) was observed in women whose temperature increased by at least 0.5 °C during labor. Our findings suggest that RVM can be a useful noninvasive technology to investigate pulmonary physiology during labor. The association between maternal MV and temperature change during labor analgesia deserves further investigation. Trial Registrationwww.clinicaltrials.gov (NCT02339389).
AB - Measuring continuous changes in maternal ventilation during labor neuraxial analgesia is technically difficult. Consequently, the magnitude of pulmonary minute ventilation (MV) alterations following labor analgesia remains unknown. We hypothesized that a novel, bio-impedance based non-invasive respiratory monitor would provide this information. Furthermore, we sought to determine if an association between changes in MV and maternal temperature existed. Following calibration with a Haloscale Standard Wright Respirometer, the ExSpiron respiratory volume monitor (RVM) measured MV, respiratory rate (RR), and tidal volume (TV) in 41 term parturients receiving epidural analgesia. Simultaneously, maternal oral temperatures were recorded at pre-specified hourly intervals after epidural analgesia initiation until delivery. Cumulative MV changes were calculated as the integral of MV change over time: MV (∫0TΔMVdt), where T represents the time between epidural placement and variable measurement. The association between changes in MV and cumulative MV versus maternal temperature was determined by comparing patients whose temperature did or did not increase by ≥ 0.5 °C. After initiation of epidural analgesia, MV decreased by 11.1 ± 27.6% [mean ± SD] at 30 min, p = 0.006, and 19.8 ± 26.1% at 2 h compared to baseline (12.6 ± 7.3 L/min at baseline vs. 15.3 ± 6.3 L/min at 2 h, p < 0.001), Minute ventilation remained decreased at 4 h by 14.3 ± 31.4% (p = 0.013). The cumulative MV also decreased by 437 ± 852 L [mean ± SD], p = 0.009) at 2 h and by 795 ± 1431 L, p < 0.001) at 4 h following epidural analgesia initiation, compared to baseline. The association between changes in cumulative MV and maternal temperature following epidural placement was weak (R < 0.3); however, a decrease in MV at 30 min (p = 0.002) and cumulative MV at 2 h (p = 0.012) was observed in women whose temperature increased by at least 0.5 °C during labor. Our findings suggest that RVM can be a useful noninvasive technology to investigate pulmonary physiology during labor. The association between maternal MV and temperature change during labor analgesia deserves further investigation. Trial Registrationwww.clinicaltrials.gov (NCT02339389).
KW - Epidural related maternal fever
KW - Labor neuraxial analgesia
KW - Maternal ventilation during labor neuraxial analgesia
UR - http://www.scopus.com/inward/record.url?scp=85068820153&partnerID=8YFLogxK
U2 - 10.1007/s10877-019-00349-1
DO - 10.1007/s10877-019-00349-1
M3 - Article
C2 - 31286333
AN - SCOPUS:85068820153
SN - 1387-1307
VL - 34
SP - 567
EP - 574
JO - Journal of Clinical Monitoring and Computing
JF - Journal of Clinical Monitoring and Computing
IS - 3
ER -