Arterial Pressure Variation as a Biomarker of Preload Dependency in Spontaneously Breathing Subjects - A Proof of Principle.
OBJECTIVE
Pulse (PPV) and systolic pressure variation (SPV) quantify variations in arterial pressure related to heart-lung interactions and have been introduced as biomarkers of preload dependency to guide fluid treatment in mechanically ventilated patients. However, respiratory intra-thoracic pressure changes during spontaneous breathing are considered too small to affect preload and stroke volume sufficiently for the detection by PPV and/or SPV. This study addressed the effects of paced breathing and/or an external respiratory resistance on PPV and SPV in detecting preload dependency in spontaneously breathing subjects.


METHODS
In 10 healthy subjects, hemodynamic and respiratory parameters were evaluated during progressive central hypovolemia (head-up tilt). Breathing conditions were varied by manipulating breathing frequency and respiratory resistance. Subjects responding with a reduction in stroke volume index ≥15% were classified as having developed preload dependency. The ability for PPV and SPV to predict preload dependency was expressed by the area under the ROC curve (AUC).


RESULTS
A breathing frequency at 6/min increased the PPV (16±5% vs. 10±3%, p<0.001) and SPV (9±3% vs. 5±2%, p<0.001) which was further enhanced by an expiratory resistance (PPV: 19±3%, p = 0.025 and SPV: 10±2%, p = 0.047). These respiratory modifications, compared to free breathing, enhanced the predictive value of PPV with higher accuracy (AUC: 0.92 vs. 0.46).


CONCLUSIONS
Under conditions of progressive central hypovolemia, the application of an external respiratory resistance at a breathing frequency of 6/min enhanced PPV and SPV and is worth further study for detection of preload dependency from arterial pressure variations in non-ventilated subjects.
Department of Internal Medicine, Academic Medical Center, Amsterdam, the Netherlands; Laboratory for Clinical Cardiovascular Physiology, Center for Heart Failure Research, Academic Medical Center, Amsterdam, the Netherlands.
Anne-Sophie G T
AS
Bronzwaer
AMC Heart Center, Academic Medical Center, Amsterdam, the Netherlands; Laboratory for Clinical Cardiovascular Physiology, Center for Heart Failure Research, Academic Medical Center, Amsterdam, the Netherlands.
Dagmar M
DM
Ouweneel
Department of Anatomy, Embryology and Physiology, Academic Medical Center, Amsterdam, the Netherlands; Laboratory for Clinical Cardiovascular Physiology, Center for Heart Failure Research, Academic Medical Center, Amsterdam, the Netherlands.
Wim J
WJ
Stok
Laboratory for Clinical Cardiovascular Physiology, Center for Heart Failure Research, Academic Medical Center, Amsterdam, the Netherlands; Edwards Lifesciences BMEYE, Amsterdam, the Netherlands.
Berend E
BE
Westerhof
Department of Internal Medicine, Academic Medical Center, Amsterdam, the Netherlands; Department of Anatomy, Embryology and Physiology, Academic Medical Center, Amsterdam, the Netherlands; Laboratory for Clinical Cardiovascular Physiology, Center for Heart Failure Research, Academic Medical Center, Amsterdam, the Netherlands; MRC/Arthritis Research UK Centre for Musculoskeletal Ageing Research, Queen's Medical Centre, School of Life Sciences, University of Nottingham Medical School, Nottingham, United Kingdom.
Johannes J
JJ
van Lieshout
D000328:Adult; D062186:Arterial Pressure / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D020896:Hypovolemia / Q000503:physiopathology*; D008297:Male; D012119:Respiration; D015656:Respiratory Mechanics / Q000502:physiology*; D055815:Young Adult