Biomedical subjects

Ira H Gewolb

Publications and source records attributed to Ira H Gewolb.

5 recordsLinked to original sources

PubMed2003

Integration of suck and swallow rhythms during feeding in preterm infants with and without bronchopulmonary dysplasia.

The aim of this study was to define quantitative measures for assessing the integration and maturation of suck and swallow rhythms in preterm infants as they relate to each other. Fourteen preterm infants (eight males, six females; gestational age range 26 to 32 weeks) with bronchopulmonary dysplasia (BPD) and an age-matched cohort of 20 infants (10 males, 10 females; gestational age range 26 to 33 weeks) without BPD were studied weekly from time of initiation of oral feeding using simultaneous recordings of nipple and pharyngeal pressure. The integration of suck and swallow rhythms was quantified by using the coefficient of variation (COV) of the suck-swallow dyad interval. Infants without BPD had a significant correlation between increasing postmenstrual age (PMA) and decreasing COV of the dyadic interval (increasing stabilization; r=0.45; p=0.008). In the non-BPD cohort 35 weeks or less PMA, the mean dyadic COV was 0.42 (SD 0.12) versus 0.34 (SD 0.09) in those more than 35 weeks PMA (p=0.039). In contrast, dyadic stability in infants with BPD was not correlated with PMA. Infants with BPD of more than 35 weeks PMA had less dyadic stability (0.45, SD 0.10) than did age-matched controls (p<0.001). Dyadic stability was also correlated with feeding efficiency in the non-BPD group (r=0.46;p=0.007) but not in the BPD cohort. Therefore, ontogeny of rhythmic suckle feeding can be described quantitatively in preterm infants, allowing comparison with at-risk populations. Infants with BPD do not follow predicted maturational patterns of suck-swallow rhythmic integration.

Analysis of Variance↗

PubMed2003

Cervical accelerometry in preterm infants with and without bronchopulmonary dysplasia.

Cervical accelerometry with digital signal processing (DSP) can identify signals that are consistently associated with swallowing during feeding of infants. It is shown that these signals, called initial discrete sounds (IDSs), become more uniform with advancing postmenstrual age (PMA) in healthy preterm infants. The objectives of this study were to determine if cervical accelerometry and DSP at a higher sample rate than previously used (22 kHz versus 16 kHz), in conjunction with a DSP software package that allows manipulation of the sound files, would improve the accuracy of the previously developed variance index (VI) method of analyzing accelerometric information. The modified VI method was then used to measure developmental differences in the IDS morphology of infants with and without bronchopulmonary dysplasia (BPD). VIs were calculated for 24 feeding studies of infants of between 32 and 39 weeks PMA: 12 studies on healthy preterm infants (n = 10: three males, seven females; mean gestational age [GA] 28.6 weeks, SD 0.4; mean birthweight [BW] 1080 g, SD 82; PMA mean 35.2 weeks, SD 0.6) and 12 studies on infants with BPD (n = 7: five males, two females; GA 27.1 weeks, SD 0.4; BW 911 g, SD 71; PMA 36.2 weeks, SD 0.6). There was a significant inverse correlation between VI and PMA for the healthy preterm group (r = 0.66, m = -2.31/week,p = 0.02). There was no significant correlation between VI and PMA for the BPD cohort. The VI of infants with BPD was significantly different from that of infants without BPD (p < 0.007, multiple regression analysis, interaction PMA x Group). Additionally, using our modified VI technique, 100% of swallows were found to have the expected IDS signals.

Analysis of Variance↗

PubMed2003

Effects of oral Lactobacillus GG on enteric microflora in low-birth-weight neonates.

BACKGROUND: Colonization patterns, especially by anaerobic flora, may play an important role in neonatal gut function. Probiotics could affect disease risk either directly through colonization or indirectly by promoting changes in gut microbial ecology. METHODS: To study the ability of Lactobacillus GG(LGG) to colonize the neonatal gut and modify its microbial ecology, a prospective, randomized study was performed in 71 preterm infants of less than 2000 g birth weight. Infants less than 1500 g (24 treated, 15 control) received 10(9) LGG orally twice daily for 21 days. Those infants weighing 1500 to 1999 g (23 treated, 9 control) were treated for 8 days. Stools were collected before treatment and on day 7 to 8 (and day 14 and 21, in the infants weighing less than 1500 g) for quantitative aerobic and anaerobic cultures. RESULTS: Colonization with LGG occurred in 5 of 24 (21%) infants who weighed less than 1500 g versus 11 of 23 (47%) in larger infants. Colonization was limited to infants who were not on antibiotics within 7 days of treatment with LGG. There was a paucity of bacterial species at baseline, although larger infants had more bacterial species (1.59 +/- 0.13 (SEM) vs 1.11 +/- 0.12; P < 0.03) and higher mean log colony forming units (CFU) (8.79 +/- 0.43 vs 7.22 +/- 0.63; P < 0.05) compared with infants weighing less than 1500 g LGG. Treatment in infants weighing less than 1500 g resulted in a significant increase in species number by day 7, with further increases by day 21. This increase was mainly the result of increased Gram (+) and anaerobic species. No difference in species number was noted in controls. Mean log CFU of Gram (-) bacteria did not change in treated infants weighing less than 1500 g. However, Gram (+) mean log CFU showed a significant increase on day 21 (6.1 +/- 0.9) compared with day 0 (3.5 +/- 0.9) (P < 0.05). No significant changes in species number or quantitative counts were noted after LGG treatment in the infants weighing 1500 to 1999 g LGG was well tolerated in all infants. CONCLUSION: The neonatal response to a probiotic preparation is dependent on gestational and post-natal age and prior antibiotic exposure. Although LGG is a relatively poor colonizer in infants, especially those infants weighing less than 1500 g at birth, it does appear to affect neonatal intestinal colonization patterns.

Administration, Oral↗

PubMed2002

Changes in rhythmic suckle feeding patterns in term infants in the first month of life.

To quantify parameters of rhythmic suckle feeding in healthy term infants and to assess developmental changes during the first month of life, we recorded pharyngeal and nipple pressure in 16 infants at 1 to 4 days of age and again at 1 month. Over the first month of life in term infants, sucks and swallows become more rapid and increasingly organized into runs. Suck rate increased from 55/minute in the immediate postnatal period to 70/minute by the end of the first month (p<0.001). The percentage of sucks in runs of > or =3 increased from 72.7% (SD 12.8) to 87.9% (SD 9.1; p=0.001). Average length of suck runs also increased over the first month. Swallow rate increased slightly by the end of the first month, from about 46 to 50/minute (p=0.019), as did percentage of swallows in runs (76.8%, SD 14.9 versus 54.6%, SD 19.2; p=0.002). Efficiency of feeding, as measured by volume of nutrient per suck (0.17, SD 0.08 versus 0.30, SD 0.11 cc/suck; p=0.008) and per swallow (0.23, SD 0.11 versus 0.44, SD 0.19 cc/swallow; p=0.002), almost doubled over the first month. The rhythmic stability of swallow-swallow, suck-suck, and suck-swallow dyadic interval, quantified using the coefficient of variation of the interval, was similar at the two age points, indicating that rhythmic stability of suck and swallow, individually and interactively, appears to be established by term. Percentage of sucks and swallows in 1:1 ratios (dyads), decreased from 78.8% (SD 20.1) shortly after birth to 57.5% (SD 25.8) at 1 month of age (p=0.002), demonstrating that the predominant 1:1 ratio of suck to swallow is more variable at 1 month, with the addition of ratios of 2:1, 3:1, and so on, and suggesting that infants gain the ability to adjust feeding patterns to improve efficiency. Knowledge of normal development in term infants provides a gold standard against which rhythmic patterns in preterm and other high-risk infants can be measured, and may allow earlier identification of infants at risk of neurodevelopmental delay and feeding disorders.

Breast Feeding↗

PubMed2002

Cervical accelerometry in preterm infants.

The objective of this study was to develop a method to use digital signal processing (DSP) technology to describe quantitatively and statistically swallow-associated sounds in preterm infants and to use this method to analyze changes as infants mature. Twelve recordings of accelerometric and physiological data on bottle-feeding preterm infants between 32 and 39 weeks' postmenstrual age (PMA) were analyzed. Cervical auscultation was performed using an accelerometer attached over the larynx. Acoustic data were recorded and graphically displayed using DSP software. Initial discrete sounds (IDSs) were identified and used to construct an average waveform from which a 'variance index' (VI) was calculated for each infant. The shape of the IDS waveforms became progressively more uniform with advancing PMA, as indicated by a significant inverse correlation between VI and PMA (r=0.739; p=0.006). DSP technology facilitated the development of a new method to quantitatively analyze feeding in preterm infants. This method provides an elegant tool to track maturation of infant feeding and assessing feeding readiness. This technique makes the interpretation of cervical auscultation data less subjective by replacing the verbal description of the sounds of feeding with quantitative numeric values. It is anticipated that this method can be automated to facilitate further the analysis of cervical accelerometry data.

Acoustics↗