Evaluation of blood pressure using Korotkoff’s sounds in case of auscultatory gap

Objective. To assess the clinical signifcance of auscultatory gap (AG) found by the 24-hour ambulatory blood pressure monitoring (ABPM) using the Korotkoff’s sounds (KS) and its potential causes.

Design and methods. 24-hour ABPM was performed in 60 patients (mean age 51,3 years, range 22–85 years), including 24 women and 36 men. In 24 patients, hypertension was diagnosed. In total, 2333 blood pressure (BP) measurements without “noise contamination” were selected for subsequent analysis (38,9 measurements per patient; from 28 to 73 measurements). The simultaneous recording of electrocardiogram (ECG), brachial cuff pressure, and KS phonograms on the right hand, as well as continuous recording of non-invasive BP curve in the left fnger using the volume clamp technique were performed in 10 patients with AG.

Results. Based on the 24-hour ABPM, AG was shown in 43 of 60 subjects (71,7%). The AG was found to be associated with a decreased amplitude of fluctuations of the cuff pressure; upon its termination, the amplitude recovered. The above synchrony of changes in KS and amplitude of pressure fluctuations was found in all 124 cases which demonstrated AG during BP measurement. We assume that AG is a true variation of BP rather than a feature of KS, as the fluctuation amplitude depends on the ratio of BP and cuff pressure but does not depend on the KS phase. To test the hypothesis, the cuff pressure and KS were compared to the continuously monitored arterial pressure. When the systolic arterial pressure exceeded the cuff pressure, the KS appeared. Later on, the BP fluctuations led to a decrease in systolic BP; the arterial pressure did not reach the cuff pressure and, therefore, KS were not recorded. Subsequent decrease in the cuff pressure led to re-appearance of KS.

Conclusions. The auscultative gap phenomenon is associated with true (mostly respiratory) variations of systolic BP rather than with features of KS in individual patients. The initial and repetitive KS occur at certain systolic BP levels depensing on the BP respiratory fluctuations and may indirectly indicate the amplitude of fluctuations.

1. Krylov DO. The determination of the blood pressure by the acoustical means of NS Korotkov. Izvestiya Imperatorskoi VoennoMeditsinskoy Akademii = Reports of the Imperial Military Medicine Academy. 1906;13(2):113–135. In Russian.

2. Korotkoff NS. On the subject of methods of measuring blood pressure. Izvestiya Imperatorskoi Voenno-Meditsinskoy Akademii = Reports of the Imperial Military Medicine Academy. 1905;11(4):365–367. In Russian.

3. Order of the Ministry of Health of the Russian Federation No. 4 of January 24, 2003 “On measures on improvement of the organization of medical care for patients with arterial hypertension in the Russian Federation”. In Russian.

4. Tikhonenko VM, Rogoza AN, Gorieva SB, Pavlova ТS. Two methods of measuring BP with 24-hour ambulatory monitoring. Functional Diagnostics. 2007;(1):52–57. In Russian.

5. Pivovarov VV, Lebedeva MA, Pankova NB, Noskin LA, Rumyantsev AG. Diagnosis of the functional state of the cardiovascular system of the child’s body by the method of spiroarteriocardiorhythmography. Russian Pediatric Journal. 2005;8(1):8–12. In Russian.

6. Pivovarov VV. A Spiroarteriocardiorhythmograph. Biomedical Engineering. 2006;40(1):45–47.

7. Pivovarov VV. Information-measuring system for functional diagnostics of nervous regulation of blood circulation. Part II. The implementation. Automation and Remote Control. 2011;72(3): 671–676.

8. Pivovarov VV, Zaitsev GK, Sizov VV. Adaptive exercise stress system SAKR-VELO for Load Tests. Biomedical Engineering. 2015;49 (2):74–78.

9. Parati G, Casadei R, Groppelli A, Di Rienzo M, Mancia G. Comparison of fnger and intra-arterial blood pressure monitoring at rest and during laboratory testing. Hypertension. 1989;13 (6 Pt 1):647–655.

10. Martina JR, Westerhof BE, van Goudoever J, de Beaumont EM, Truijen J, Kim YS et al. Noninvasive continuous arterial blood pressure monitoring with Nexfn. Anesthesiology. 2012;116 (5):1092–1103.

11. O’Briena E, Atkinsb N, Stergiou G, Karpettas N, Parati G et al. European society of hypertension international protocol revision 2010 for the validation of blood pressure measuring devices in adults. Blood Pressure Monitoring. 2010;15(1):23–38.

12. Askey JM. The Auscultatory gap in sphygmomanometry. Ann Intern Med. 1974;80(1):94–97.

13. Cavallini MC, Roman MJ, Blank SG, Pini R, Pickering TG, Devereux RB. Association of the auscultatory gap with vascular disease in hypertensive patients. Ann Inter Med. 1996;124 (10):877–883.

14. Frech TM, Penrod J, Battistone MJ, Sawitzke AD, Stults BM. The revalence and clinical correlates of an auscultatory gap in systemic sclerosis patients. Int J Rheumatol. 2012;2012(1):590845. doi:10.1155/2012/590845

15. Blank SG, West JE, Miiller FB, Pecker MS, Laragh JH, Pickering TG. Characterization of auscultatory gaps with wideband external pulse recording. Hypertension. 1991;17(2):225–233.