Diaphragmatic Activity and Ventilation in Preterm Infants
| Autor: | Henrique Rigatto, Francisco J.C. Reis, Leanne V. Landriault, Donald B. Cates |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Inhalation
medicine.diagnostic_test business.industry Birth weight Diaphragmatic breathing Respiratory physiology Electromyography Tonic (physiology) Work of breathing medicine.anatomical_structure Control of respiration Anesthesia Pediatrics Perinatology and Child Health Breathing medicine Respiratory muscle Abdomen Expiration business Respiratory minute volume Tidal volume Developmental Biology |
| Zdroj: | Neonatology. 65:16-24 |
| ISSN: | 1661-7819 1661-7800 |
| DOI: | 10.1159/000244022 |
| Popis: | To determine the effects of inhaled CO2 and abdominal loading on diaphragmatic electromyography (EMGdi) and ventilation during sleep, we studied 10 preterm infants (birth weight 1,840 ± 50 g; gestational age 32 ± 0.6 weeks and postnatal age 10.4 ± 1.4 days). We measured surface and esophageal diaphragmatic activity. Ventilation was measured using a nasal flowmeter and a flow-through system. Diaphragmatic activity was analyzed for the duration of total phasic and expiratory activities, the expiratory to total phasic activity ratio and the presence of tonic activity (defined by the presence of electrical activity of the diaphragm at the end of expiration). With 3% CO2 in quiet and REM sleep, the intensity of EMGdi increased, but the duration of total phasic activity, the expiratory to total phasic activity ratio and tonic activity did not change. During quiet sleep with 3% CO2, ventilation increased (0.392 ± 0.028 to 0.616 ± 0.058 1/ min; p = 0.001) due to an increase in tidal volume and frequency. Similar changes occurred in REM sleep. Abdominal loading with sandbags increased the duration of total phasic activity (0.68–0.78 s; p = 0.03), expiratory phasic activity (0.21–0.32 s; p = 0.01), the expiratory to total phasic activity ratio (0.28–0.39; p = 0.03) and diaphragmatic tonic activity (20–60%; p = 0.04) as measured with surface electrodes in REM sleep. It also increased the expiratory to total phasic activity ratio and tonic activity, as measured with surface electrodes in quiet sleep. Abdominal loading did not alter ventilation or the structure of the average breath in either sleep state. These findings indicate that: (1) in healthy preterm infants, inhaled CO2 alters EMGdi and the structure of the average breath in a similar manner: the activity increases but timing and tonus are not changed, and (2) abdominal loading alters the structure of diaphragmatic activity as recorded by surface and esophageal electrodes with a significant increase in expiratory activity and tonus, but it does not alter the structure of the average breath. |
| Databáze: | OpenAIRE |
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