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  • Meeting abstract
  • Open Access

The cardiac chemoreflex sensitivity (cCRS) and the influence of respiration

  • 1,
  • 1,
  • 2 and
  • 1
Critical Care20003 (Suppl 1) :P127

  • Published:


  • Public Health
  • Heart Rate
  • Mathematical Model
  • Healthy Volunteer
  • Emergency Medicine


Assessment of cCRS may be a predictor of serious arrhythmic events after survived sudden cardiac death. However, chemoreceptor (CR) stimulation produces not only cardiovascular but also respiratory responses. The aim of this study was to correct the respiratory influence on apparent values of cCRS.


The cCRS was assessed in 47 healthy volunteers during free breathing (FB). Twenty subjects underwent further monitoring during controlled breathing (CB, fixed minute ventilation). Peripheral arterial CTs were stimulated by 5 min of hypoxia (10% O2 in N2). Cardiac CRS was calculated asΔ heart rate interval/ΔpO2. We developed a mathematical model to reduce the respiratory influence on cCRS, and calculated a respiration independent second cCTS value using this correction. The corrected cCRS was compared with cCRS values experimentally obtained during CB.


Cardiac chemoreflex sensitivity under free and controlled breathing


Our results suggest that ventilation causes a major disturbance in the measurement of cardiac chemoreflex sensitivity. We argue that this disturbance should be minimised to obtain correct values of cardiac chemoreflex sensitivity for predicting serious arrhythmic events.

FB (corrected





pCCS (ms/mmHg)

1.53 ± 0.32

3.64 ± 0.81*

0.89 ± 0.91 NS

* P < 0.05 versus controlled breathing (CB), NS, not significant versus CB.

Authors’ Affiliations

Department of Medicine III/Cardiac Intensive Car, Institute of Physiology, University Halle, Halle, 06097, Germany
NHLI, London, SW3 6LY, UK


© Current Science Ltd 1999