Although the use of neuromuscular blockade decreased FRC and ventilation distribution substantially in both groups, the changes were more pronounced in young infants. With PEEP, FRC increased and ventilation homogeneity was restored. These results provide a rationale to use PEEP in anesthetized, paralyzed infants and children.

During the application of a very low PEEP of 3-cm H2O, FRC and ventilation distribution decreased significantly at an Fio2 of 1.0 compared with that at an Fio2 of 0.3. This decrease could be counterbalanced by the administration of PEEP of 6-cm H2O, indicating that a low level of PEEP is sufficient to maintain FRC and ventilation distribution regardless of the oxygen concentration.

No abstract

Laryngeal and respiratory reflex responses in children aged 2-6 yr were different between sevoflurane and propofol independent of the levels of hypnosis examined in this study.

No abstract

SummaryWe studied the effect of intravenous lidocaine on laryngeal and respiratory reflex responses in children anaesthetised with sevoflurane. We tested the hypothesis that the incidence of laryngospasm evoked by laryngeal stimulation is temporarily diminished after the administration of lidocaine. Forty children, aged between 25 and 84 months, were anaesthetised with sevoflurane and breathed spontaneously through a laryngeal mask airway. Respiratory reflex responses were elicited by spraying distilled water onto the laryngeal mucosa at three time intervals: (i) before lidocaine was administered (baseline); (ii) at 2 min and (iii) at 10 min following the intravenous administration of a bolus of lidocaine 2 mg.kg )1 . A blinded reviewer assessed the evoked responses. The incidence of laryngospasm was reduced from 38% at baseline to 15% 2 min after lidocaine administration (p < 0.02) and 18% 10 min after lidocaine administration (p = 0.10). We conclude that intravenous lidocaine significantly reduced the incidence of laryngospasm but that the effect was short-lived. Protecting the lungs from aspiration is vitally important and is largely regulated by laryngeal and respiratory reflexes such as coughing, laryngospasm, expiration reflex, spasmodic panting and apnoea. However, exaggerated upper airway reflexes, particularly laryngospasm, have the potential to cause harm [1]. An increased incidence of laryngospasm and apnoea is observed in children compared with adults and complications resulting from hypoxaemia are more common and more severe in children [2][3][4]. Lidocaine has been demonstrated to reduce the incidence of laryngospasm in anaesthetised children [5,6]; however, its effectiveness has been questioned [7,8]. Uncertainty regarding its usefulness is partly explained by the fact that most clinical studies were underpowered to assess the relatively rare event of laryngospasm. Often more common adverse effects, such as stridor and the occurrence of hypoxaemia from whatever cause, were included in analyses assessing its incidence. Furthermore, studies examining the action of intravenous lidocaine on cough suppression during tracheal intubation revealed that the effect may only last a few minutes [9]. The potentially transient nature of this effect might make evaluation in the clinical setting difficult.

No abstract

This study shows that all children had a preserved upper airway at all measured sites during propofol sedation. Chin lift caused a widening of the entire pharyngeal airway that was most pronounced between the tip of the epiglottis and the posterior pharyngeal wall. In pediatric patients, chin lift may be used as a standard procedure during propofol sedation.