Anesthetics Research

Respiratory complications still remain the leading cause of morbidity in children undergoing anesthesia or sedation for diagnostic and surgical interventions. Our group has a longstanding record of research activities exploring A) effects of anesthetic drugs and B) airway instrumentation and respiratory monitoring in these children.

A) Multiple functions of the larynx are controlled by basic reflexes. In spite of the clinical significance of these reflexes, information on anaesthetized humans is still very limited, not least related to the practical difficulty of assessing laryngeal function in vivo, especially in anesthetized patients. Among the protective reflexes, laryngospasm occurs more frequently during the administration of anesthesia to pediatric patients compared with adult patients. Although laryngospasm can be safely treated when experienced personnel are at hand, it remains the most commonly reported respiratory-related cause of perioperative cardiac arrest, rendering progress in the diagnosis, prevention and treatment of laryngospasm in anesthetized children mandatory. One of our last contributions in this field assessed the potential protective effect of intravenous administration of lidocaine on the incidence of laryngospasm in children anesthetized with sevoflurane. This study confirmed our hypothesis of a significant transient reduction of the incidence of laryngospasm (by 40%).¹ Moreover we recently could show that although general clinical experience suggests more common laryngeal reflex responses under light levels of anesthesia occurrence of laryngospasm could still be observed in 18% of children under deeper levels of anesthesia with sevoflurane.² Our further activities on this group of themes will focus on additional conditions (airway infection, drugs) known to alter the susceptibility of laryngospasm, ultimately drawing a detailed picture of reflex responses.

B) Airway instrumentation and respiratory monitoring is a critical activity in anesthesia and critical care. Especially in infants and young children the great vulnerability of the airway mandates meticulous and precise management. Even the correct placement of the tip of the endotracheal tube is notoriously difficult given the short distances and the broad inter-individual variability. Unsurprisingly, various techniques are in use to guide positioning. We could show that the new and simple to use technique of palpating the cuff at the suprasternal notch was equal up to superior in comparison with commonly used techniques for the predictability of the tube tip position.³ Our further research in this field will focus on respiratory monitoring in anesthetized, spontaneous breathing infants during diagnostic and therapeutic procedures.

References:

¹    Erb TO, Ungern-Sternberg von BS, Keller K, Frei FJ. The effect of intravenous lidocaine on laryngeal and respiratory reflex responses in anaesthetised children. Anaesthesia. 2012; 68(1):13–20.

²    Erb TO, Ungern-Sternberg von BS, Moll J, Frei FJ. Impact of high concentrations of sevoflurane on laryngeal reflex responses. Pediatric Anesthesia; accepted for publication on 31-Oct-2016.

³    Moll J, Erb TO, Frei FJ. Assessment of three placement techniques for individualized positioning of the tip of the tracheal tube in children under the age of 4 years. Pediatric Anesthesia. 2014; 25(4):379–85.