ABSTRACT
Our objective was to study how invasive mechanical ventilation impairs cardiac output
(CO) in children and adults. Although the application of continuous positive airway
pressure (CPAP) is widely practiced in neonatal intensive care, its hemodynamic consequences
have not yet been investigated. A prospective study to assess the hemodynamic effects
was conducted in 21 preterm infants < 1500 g using two-dimensional M-mode and pulsed
Doppler echocardiography during and 1 hour after discontinuation of nasal CPAP (n-CPAP).
Gestational age was 28.0 ± 1.9 weeks (mean ± standard deviation); birthweight, 1000
± 238 g; age at study entry, 200 ± 155 hours; total maintenance fluid, 154 ± 42 mL/kg/day;
and n-CPAP level, 4.4 ± 0.9 cm H2O. None of the infants received inotropic support, and n-CPAP did not cause any significant
difference in the parameters measured: stroke volume, 3.1 ± 1.0 mL (with n-CPAP) versus
3.1 ± 1.0 mL (without n-CPAP); cardiac output, 487 ± 156 mL/minute versus 500 ± 176
mL/minute; left ventricular diastolic diameter, 1.22 ± 0.15 cm versus 1.24 ± 0.14
cm; fractional shortening, 0.30 ± 0.05% versus 0.29 ± 0.04%; and aortic velocity-time
integral, 8.64 ± 1.80 cm versus 8.70 ± 1.65 cm. The n-CPAP level did not influence
CO; n-CPAP (up to 7 cm H2O) has no echocardiographically detectable hemodynamic effect in preterm infants.
Our data imply there is no need to withhold n-CPAP support to prevent circulatory
compromise in these infants.
KEYWORDS
CPAP - cardiac output - preterm infants - echocardiography
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Barbara Moritz
Department of Pediatrics, Feldkirch Academic Teaching Hospital
Carinagasse 47, A-6800 Feldkirch, Austria
