[Cardio-respirography in neonatal medicine: value, interpretation, indications]

[Determinants of diphemanil methylsulfate (Prantal) utilization: a survey of practice in the French neonatal and intensive care units]

Diphemanil methylsulfate (Prantal) is a quaternary ammonium with parasympathicolytic properties. It is used in premature and term neonates with bradycardias related to vagal hyper reflectivity (HRV).

OBJECTIVES

To assess the use of Prantal in the French neonatal and intensive care units: its indications, its modalities of use, its side effects and the number of patients treated during 1 year (2004) in France.

METHODS

A questionnaire was electronically sent to all neonatology units and all neonatal intensive care units in France.

RESULTS

Among 202 units, 121 (60%) answered the questionnaire. Prantal was reported to be used in 51 (42.1%) units. Among them, 38 (31.4%) actually treated 169 patients in 2004 with a mean number of patients treated by unit of 4. The diagnostic of HRV was supported by: a history of malaise (84.3%), bradycardia (94.1%), oculocardiac reflex (74.5%), cardiac Holter (76.4%), cardiorespirographic recording (19.6%), esophageal pHmetry (35.2%) and esophageal fibroscopy (21.5%). The mean starting dosing was 4.7 mg/kg/d, the mean maximal dosing was 9 mg/kg/d and the mean daily intakes were initially 2.3 and secondary 2.9. Prantal dosing was adjusted to weight in 54.9%, every month in 85.7%. Treatment was stopped at the mean post-natal age of 6 months, mostly in a progressive manner and without monitoring help.

CONCLUSION

Prantal was seldom used in 2004 in France for different reasons: HRV is an uncertain entity, the efficacy of Prantal has not been validated and atropinic side effects can be encountered.

Use of the oculocardiac reflex to assess vagal reactivity during quiet sleep in neonates

Arousal from sleep can be a protective response to life-threatening stimuli. Hence, faults within state-switching processes may lead to fatal events. To investigate the role of the nervous system during cardiac failure triggered by phasic, vagally mediated stimulation, we analysed autonomic and behavioural reactions in 50 premature neonates during quiet sleep (QS) -- a sleep state characterized by a preponderance of tonic, parasympathetic activity. Bradycardia was induced with a standardized ocular compression test. Neither awakening nor behavioural escape reactions were observed during or after an episode of bradycardia. Eighty-six per cent of the provoked bradycardic episodes induced central apnoea. During QS, the neonates' respiratory response and arousability were found to be time-dependent: when the test was performed early in the QS episode, apnoea was more frequent (94%), and no sleep state change occurred. When ocular compression was performed in the later part of the QS episode, a transition towards active sleep was observed, together with significantly fewer episodes of apnoea (64%). These results indicate that a progressive decrease in the respiratory system's responsiveness to phasic, parasympathetic stimulation occurs during QS, whereas arousability increases. Our study suggests that newborns could be more vulnerable to potentially fatal events during the initial portion of a QS episode.