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Critical Care

Open Access

Intrathoracic blood volume is not a sensitive indicator for hypervolaemia in healthy, mechanically ventilated pigs

  • G Marx1,
  • S Pedder1,
  • S Swaraj1,
  • U Pfeiffer2 and
  • M Leuwer1
Critical Care20037(Suppl 2):P188

Published: 3 March 2003


Cardiac OutputMean Arterial PressureCentral Venous PressureSensitive IndicatorPulmonary Artery Catheter


Intrathoracic blood volume (ITBV) measured by the transpulmonary technique has been suggested as an alternative parameter predicting cardiac preload in critically ill patients [1]. So far, it has never been shown that by measuring ITBV it is possible to detect hypervolaemia.


Prospective animal laboratory study.


University animal laboratory.


Healthy, anaesthetized, and mechanically ventilated pigs (n = 4) with a median weight of 24.5 kg (23.3–26.5 kg) were investigated. A pulmonary artery catheter (831HF75, 7.5 F Edwards Lifesciences Ltd) inserted via the right jugular vein and an arterial catheter for transpulmonary thermodilution (4 F PV 2014L16, Pulsion Medical Systems) was inserted into the right carotid artery. Measurements of haemodynamic parameters included heart rate (HR), mean arterial pressure (MAP), cardiac output (CO), pulmonary arterial occlusion pressure (PAOP), central venous pressure (CVP), extravascular lung water (EVLW) and ITBV. After baseline measurement, hypervolaemia was induced by stepwise (10% per step) cumulative administration of 50% of the estimated blood volume of the animals (80 ml/kg) using 6% hydroxyethylstarch 200/0.5. The interval between each of the five steps was 10 min. Haemodynamic parameters, EVLW and ITBV before and after hypervolaemia were compared by Friedman's test. Data are presented as the median and interquartile range. P < 0.05 was considered significant.


After establishment of hypervolaemia the following parameters increased significantly: HR from 85 beats/min (68–103) to 130 beats/min (124–134), MAP from 98 mmHg (96–101) to 116 mmHg (107–128), CO from 120 ml/min per kg (100–138) to 190 ml/min per kg (156–233), EVLW from 3.9 ml/kg (3.5–8.5) to 19.0 ml/kg (14.8–24.2), CVP from 9 mmHg (8–9) to 27 mmHg (25–30), and PAOP from 10 mmHg (10–11) to 27 mmHg (25–27), whereas ITBV did not change significantly from 21.9 ml/kg (19.0–24.7) to 23.1 ml/kg (20.8–26.3).


Intrathoracic blood volume is not a sensitive indicator for hypervolaemia in healthy, mechanically ventilated pigs in the presence of severely increased EVLW.

Authors’ Affiliations

University Department of Anaesthesia, University of Liverpool, Liverpool, UK
Technical University of Munich, Germany


  1. Sakka SG, Bredle DL, Reinhart K, et al.: J Crit Care 1999, 14: 78-83. 10.1016/S0883-9441(99)90018-7View ArticlePubMedGoogle Scholar


© BioMed Central Ltd 2003