Electrical activity of the diaphragm following a loading dose of caffeine citrate in ventilated preterm infants

Abstract

Conflict of interest:Professor Greenough has a non-conditional educational grant from SLE to support her research on optimising neonatal ventilation. Category of study: ClinicalWhat is the key message of your article?• Intravenous administration of caffeine citrate in ventilated, prematurely born neonates transiently increased the diaphragmatic EMG activity and improved respiratory function. What does it add to the existing literature?• This is the first study to assess the impact of caffeine on the diaphragmatic EMG activity in ventilated neonates. What is the impact?• Our results describe a mechanism by which caffeine administration might facilitate extubation of ventilated, prematurely born infants. ABSTRACTBackground: Administration of caffeine citrate can facilitate extubation. Our aim was to determine whether a loading dose of caffeine citrate given to ventilated, preterm infants affected the diaphragm electrical activity. Methods: Infants < 34 weeks of gestational age were recruited if requiring mechanical ventilation and prescribed a loading dose of caffeine citrate. Surface electrodes recorded the electrical activity of the diaphragm (dEMG) before and after administration of intravenous caffeine citrate. The mean amplitude of the EMG (dEMG) trace and the mean area under the EMG curve (aEMGc) were calculated.Results: Thirty-two infants were assessed with a median gestational age of 29 (27 to 31) weeks. The dEMG amplitude increased, peaking at 25 minutes post administration (p=0.006) and the increase in aEMGc (p= 0.004) peaked at 30 minutes, the differences were not significant after 60 minutes. At 20 minutes there was an increase in minute volume (p= 0.034) and a reduction in the peak inspiratory pressure (p= 0.049). Conclusion:We have demonstrated a transient increase in both electrical activity of the diaphragm and respiratory function following an intravenous loading dose of caffeine citrate.

Direct Effect of Caffeine on Diaphragmatic Muscles in Preterm Babies Through Ultrasonographic Examination

“…Therefore, in our study the immediate evaluation within 5 minutes was chosen for re-evaluation of diaphragm activity to identify the change after caffeine loading dose. On the other hand, Williams et al 13 evaluated 32 infants under 34 gestational week born by using dEMG before and after caffeine loading dose and identi ed a signi cant increase in dEMG amplitude at 25 minutes that peaked at 30 minutes 13 . Therefore, the evaluation at 5 minutes rather than at 25 minutes may be the reason of no change in the right diaphragm thicknesses and velocities observed in our study.…”

“…In comparison with other methylxanthines, caffeine was shown to have a greater effect on diaphragm than theophylline in both experimental and clinical studies 10,11 . The treatment also increased diaphragmatic activity, tidal volume, lung function and muscle strength in preterm babies 2,12,13 . There were two studies included preterm infants and showed transient increase in electrical activity of the diaphragm after caffeine assignment 12,13 .…”

“…The treatment also increased diaphragmatic activity, tidal volume, lung function and muscle strength in preterm babies 2,12,13 . There were two studies included preterm infants and showed transient increase in electrical activity of the diaphragm after caffeine assignment 12,13 . Its bene cial effects on lung compliance and function were also demonstrated by measurement of lung volume, respiratory system compliance and resistance 2 .…”

“…Diaphragm function can be evaluated by electrical phrenic nerve stimulation with electromyography (EMG) and uoroscopy [14][15][16] . Recently, ultrasonography (US) has been considered as a promising technique [13][14][15][16][17] . It has many advantages over other methods.…”

Prediction of extubation success using the diaphragmatic electromyograph results in ventilated neonates

“…An alternative explanation for our negative results is that transcutaneous measurements were too insensitive to detect differences. We, however, think this is unlikely as we have demonstrated changes in the transcutaneous EMG signal following the administration of a loading dose of caffeine [22]. We calculated the NVE using expiratory tidal volumes, as these are less prone to errors due to leak around the endotracheal tube and we used Coles tubes around which there is minimal or no leak [23].…”