Ellen de Kort

154 Chapter 9 adding a muscle relaxant led to fewer and shorter oxygen desaturations. 34 Observational studies also showed a relatively high first attempt success rate and a high frequency of adequate intubating conditions. 46,47 More recent studies have shown that the use of paralytic medication in combination with a sedative or analgesic compared to a sedative or analgesic alone leads to fewer intubation attempts and a lower incidence of intubation related adverse events. 1,9,48 The use of an analgesic or sedative without a paralytic even led to more severe desaturations. 1,48 These results could indicate that the use of an analgesic or sedative alone is more harmful than awake intubation. These data, however, should be interpreted with caution. Of all patients treated with only an analgesic or a sedative in this study population, 35% were treated with morphine. 36 Because of its delayed onset of action, morphine is not a suitable candidate to be used as premedication. 49 The results do indicate that the use of a muscle relaxant besides an analgesic or a sedative improves patient safety during intubation. The use of a muscle relaxant can improve intubation conditions but can also be used to prevent or treat chest wall rigidity that is a common side effect of analgesics, mainly fentanyl and remifentanil. Multiple muscle relaxants are available but there is no clear evidence on which muscle relaxant is most effective and safe in the neonatal population. Succinylcholine was frequently used previously, but has been abandoned because of rare but serious side effects such as malignant hyperthermia and acute rhabdomyolysis with hyperkalemia. 34,46 This has led to the use of the non-depolarizing muscle relaxants atracurium, mivacurium and rocuronium in the neonatal population, 34,44,46,47 but without comparison between different muscle relaxants. Important for a muscle relaxant when used as premedication for endotracheal intubation is a short duration of action, to allow for quick recovery of spontaneous respirations which contribute to tidal volumes and, therefore, lead to lower inspiratory peak pressures during volume targeted ventilation. Mivacurium seems a suitable candidate, with a short onset of effect and a mean duration of action between 11 and 16 minutes in the newborn population. 34,46 There have been availability issues with mivacurium in some countries, for example North America, 32 but this does not apply for the Netherlands. Rocuronium also has a rapid onset of action but has a longer duration of muscle relaxation of up to 1 hour, which is probably to long for this purpose. Feltman et al. could not reproduce this relative long duration of action and found a duration of paralysis of 16 minutes. 44 This could make rocuronium a suitable candidate, but further research is needed. Another important factor is that the muscle relaxant should have a shorter period of action compared to the analgesic/sedative that is used, to prevent patients from being consciously paralyzed.