Nasal continuous positive airway pressure affects pre- and postprandial intestinal blood flow velocity in preterm infants

Abstract

Objective: To measure the effect of nasal continuous positive airway pressure (CPAP) on intestinal blood flow velocity responses to enteral feedings and left ventricular output (LVO).Study Design: Eighteen infants completed the study (birth weight 1793±350 g, gestational age 32.1±1.1 weeks). On the day infants were weaned from CPAP to room air, pre-and postprandial (0, 30, 60 and 90 min after feeding) mean velocity (MV), peak systolic velocity (PSV) and end diastolic velocity (EDV) were measured for one feeding given when receiving CPAP ('on CPAP'), and for one feeding given after CPAP had been discontinued ('off CPAP'). Preprandial LVO was measured before and after CPAP discontinuation.Result: MV and PSV were significantly lower when infants were on CPAP (P<0.05). Maximum postprandial MV, PSV and EDV occurred at 30 min when on CPAP and at 60 min when off CPAP. Preprandial LVO was similar when infants were on and off CPAP. Keywords: nutrition; neonate; Doppler ultrasound; CPAP belly syndrome; respiratory distress syndrome; cardiac output Introduction Nasal continuous positive airway pressure (CPAP) is used increasingly for the treatment of respiratory distress in premature neonates. Compared with intubation or mechanical ventilation, CPAP is associated with decreased incidence of bronchopulmonary dysplasia and sepsis, and with a trend toward decreased incidence of retinopathy of prematurity and intraventricular hemorrhage.

Regional tissue oxygenation in preterm born infants in association with echocardiographically significant patent ductus arteriosus

“…Significantly lower mesenteric tissue oxygenation was recorded in infants with a large PDA on NCPAP, but not in the mechanically ventilated neonates. Large transductal size and NCPAP, which is a known factor that influences mesenteric artery blood flow velocity in preterm infants, 29,30 is one possible explanation for this finding, although reduction in mesenteric blood flow does not always impair Regional tissue oxygenation in infants with PDA A Petrova et al mesenteric tissue oxygenation. 31 We did not find a decrease in mesenteric tissue oxygenation in infants with moderate PDA on NCPAP, maybe because of the inadequate number of observed cases with moderate PDA on CPAP (n ¼ 2).…”

Effects of a Patent Ductus Arteriosus on Postprandial Mesenteric Perfusion in Premature Baboons

“…Therefore, our experimental design does not allow us to determine whether the differences between the groups are due to the PDA shunt, itself, or to factors that might coexist in animals that fail to close their ductus spontaneously. Although the distribution of several factors known to affect the postprandial, hyperemic response (e.g., initial degree of illness and postnatal age (28, 29), prior exposure to feedings (11, 28), feeding volume (22, 29), exposure to phototherapy (30), and degree of mechanical ventilation at the time of study (21)) were similar between the two groups, other unknown conditions may have contributed to our findings. Our experimental model, also, does not allow us to comment on the role of a PDA with larger feeding volumes, or of the immature intestine's ability to increase its oxygen extraction.…”

“…Peak-systolic, end-diastolic, and time-averaged mean SMA velocity measurements were obtained from the peak velocity envelope of three consecutive cardiac cycles. We calculated two separate pulsatility indices [PI (mean) and PI (peak)] for each set of velocity measurements, since each of these measurements has been used as a surrogate for SMA impedance {PI (mean) = (peak systolic velocity – end diastolic velocity)/ time-averaged mean velocity (14); PI (peak) = (peak systolic velocity – end diastolic velocity)/ peak systolic velocity (21)}. We also calculated the SMA relative vascular resistance as a surrogate measure of resistance (relative vascular resistance = mean arterial blood pressure divided by mean SMA velocity) (22, 23).…”

Gastric Dysmotility in Critically Ill Children

“…(29) Propofol at low doses in healthy volunteers does not affect GE. In critically ill patients, proposal delayed GE and gastric meal retention less than morphine and midazolam (35,38). The alpha-adrenoreceptor agonists, dexmedetomidine and clonidine, have been found to delay GE and decrease antral contractions, respectively, in healthy volunteers.…”

“…Reduced gastric blood flow in healthy volunteers and neonates on continuous positive pressure has been reported. (37, 38) Activation of the renin-angiotensin axis and inflammatory cascade by positive pressure ventilation may also lead to decreased splanchnic circulation and affect gut motility. (39-41) Decreased splanchnic circulation may result in poor intestinal perfusion, which has been associated with mucosal injury, impaired mucosal barriers and altered motility.…”