COMPARISON OF TRANSTRACHEAL AND EXTRAVASCULAR DOPPLER DETERMINATIONS OF STROKE VOLUME AND CARDIAC-OUTPUT AT VARIOUS STATES OF VOLUME LOADING IN PIGLETS
Rj. Peterson et al., COMPARISON OF TRANSTRACHEAL AND EXTRAVASCULAR DOPPLER DETERMINATIONS OF STROKE VOLUME AND CARDIAC-OUTPUT AT VARIOUS STATES OF VOLUME LOADING IN PIGLETS, Critical care medicine, 23(12), 1995, pp. 2015-2022
Objective: To assess the applicability of a new technology in neonates
. Transtracheal Doppler and extravascular Doppler determinations of st
roke volume and cardiac output were compared with thermodilution measu
rements at various states of volume loading in an animal model. Design
: Prospective, descriptive study. Setting: Animal research laboratory
at; a university medical center. Subjects: Fourteen newly weaned pigle
ts, weighing 2.8 to 6.5 kg. Interventions: Doppler probes were placed
on the endotracheal tube tip (transtracheal Doppler) and directly on t
he aortic adventitia (extravascular Doppler). A 4-Fr thermodilution ca
theter was inserted in the pulmonary artery, Stroke volume and cardiac
output determinations were recorded at baseline, after a 15-mL/kg vol
ume load and after successive 15-mL/kg blood withdrawals to exsanguina
tion or a systolic blood pressure of <20 mm Hg. Measurements and Main
Results: Transtracheal and extravascular Doppler measurements of cardi
ac output were not significantly different from thermodilution at any
physiologic state. These techniques were able to measure stroke volume
s and cardiac outputs at the low levels seen in severe hemorrhagic sho
ck. Conclusions: Transtracheal Doppler and extravascular Doppler measu
rements of cardiac output compare favorably with thermodilution. These
methods effectively followed trends from alterations in intravascular
volume, even at very high heart rates and small stroke volumes. Trans
tracheal Doppler and extravascular Doppler should yield useful informa
tion in critically ill neonatal patients, where data regarding stroke
volume and cardiac output may be useful in clinical management.