(560.11) A Preliminary Report on the Variation of Respiratory Blood Pressure during Sleep in Normal Subjects

Poster Board Number: E167

Jinan Wang (Fuwai Hospital, The Affiliated Rehabilitation Hospital of Chongqing Medical University), Xingguo Sun (Fuwai Hospital), Wenqi Tai (Fuwai Hospital), Qingqing Zhou (Fuwai Hospital, The Affiliated Rehabilitation Hospital of Chongqing Medical University), Yanfang Zhang (Fuwai Hospital, The Affiliated Rehabilitation Hospital of Chongqing Medical University)

Objective:  Based on the new theory of holistic integrative physiology and medicine, we hypothesize that respiration is the origin of the variability of circulatory parameters, and initially verify this view by analyzing the relationship between blood pressure variability and respiration. 

Methods:  This study analyzed 8 normal subjects (NS) with no disease diagnosis who performed cardiopulmonary exercise testing (CPET), polysomnography (PSG), continuous fingertip pulse wave and electrocardiogram (ECG), and analyzed the correlation between the respiratory cycle of nasal airflow and blood pressure variation cycle during sleep. The respiratory cycle included complete inhalation and subsequent exhalation. Analysis and calculation of the number of breathing cycles (B-n), average breathing cycle time (Bn-T) and other parameters. Blood pressure variability is calculated using two different methods: fingertip pulse wave waveform and pulse transit time (PTT). The peak of the fingertip pulse wave represents the systolic blood pressure (SBP), and the end point represents the diastolic blood pressure (DBP). The values of the peak and end points are extracted separately and sorted separately. Continuous blood pressure rises from lowest to highest at a time, then dropped from highest to lowest, as a blood pressure variation cycle, calculation of blood pressure variation cycle (BPV-n), and other parameters. PTT can directly calculate the blood pressure value, and it calculates the blood pressure variability in the same way as the fingertip pulse wave. To compare the relationship between respiratory and blood pressure variability parameters and the similarities and differences between the two methods, independent-sample t test and paired-sample t test were used for statistical test. 

Results:  The subjects apnea hypopnea index was 1.71±1.30 events/hour. Pulse wave waveform calculation Bn (6581.63±1411.90), SBPV-n (6629.88±1479.84) and DBPV-n (6628.38±1396.37) are highly consistent during sleep. Bn/SBPV-n (1.00±0.03) and Bn/DBPV-n (0.99±0.02) is close to 1 (Pgt;0.05); Bn-T (4.19±0.57 s), average systolic blood pressure variation cycle time (4.17±0.63 s) and average diastolic blood pressure variation cycle time (4.16±0.60 s) basically the same (Pgt;0.05). SBPV-n (3988.38±1701.93) and DBPV-n (886.63±176.86) calculated by PTT during sleep were significantly lower than the calculated values of pulse wave waveform (Plt;0.01). 

Conclusion:  Normal subjects’ blood pressure variability during sleep is very similar to respiration, and the initiating factor of blood pressure variability is respiration.[KEY WORDS] holistic integrative physiology and medicine; cardiopulmonary exercise testing; polysomnography; nasal airflow; pulse wave; pulse transit time; blood pressure variability; blood pressure variation time

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