Reflex regulation and the functional assessment possibility of the cardiorespiratory system in pregnancy: a systematic review

Abstract

INTRODUCTION: Anesthesia planning for cesarean section requires knowledge of physiological and functional features a pregnant patient has in her gestational age. Proper planning reduced the perioperative critical incidents risk. OBJECTIVE: Search for data on the methods and results of assessing the cardiorespiratory status of pregnant women using methods that involve such key mechanisms of arterial baroreflex (ABR) and peripheral chemoreflex (PCR) mechanisms. MATERIAL AND METHODS: We performed a systematic review of the literature in accordance with the PRISMA guidelines. The bibliographic search was performed in December 2022 in the Medline (Pubmed), RSCI (eLibrary.ru) and Cochrane Library databases. The search keywords were: “pregnancy breath holding test”, “pregnancy chemoreflex”, “pregnancy baroreflex”, “Valsalva test pregnancy”. RESULTS: 110 documents were found, after deleting 68 papers for various reasons 42 full-text sources were analyzed, including a detailed comparative analysis of 8 sources that met totally the inclusion criteria. The design, objectives, methods, data availability, and outcomes of the studies were heterogeneous, so a meta-analysis was not performed. Were extracted and summarized data on functional changes in the work of cardiorespiratory system during pregnancy and changes in the sensitivity of the baroreflex and chemoreflex. CONCLUSIONS: The sensitivity of PCR in pregnant women can be assessed by inhalation of hyperoxic, hypercapnic and isooxic-hypercapnic gas mixtures (rebreathing test). The sensitivity of ABR in pregnant can be assessed by phenylephrine test, Valsalva test, orthostatic test, and spectral analysis of the sequences of blood pressure values and the R-R interval. The sensitivity of PCR in full-term pregnancy increases. The sensitivity of ABR in pregnant progressively decreases from the beginning of pregnancy to the end of the second trimester and increases in the postpartum period to initial level; in the third trimester of pregnancy, changes in ABR sensitivity are individual and do not have a single trend.