Ellen de Kort

99 Evaluation of an Intubation Readiness Score 6 a stronger, repetitive stimulus, to evaluate the level of sedation, thereby repeatedly exposing neonates to painful stimuli, is considered unethical. Another explanation for inadequate prediction of the level of sedation by IRS could be the short period of action of propofol. This pharmacological characteristic can cause the medication effect to be already expired at the moment the intubation is started, despite an IRS of 3 or 4 just before. This would mainly be the case in patients in whom a long period of time elapsed between reaching IRS 3 or 4 and starting the intubation attempt. However, statistical analysis revealed no significant difference in this time between patients with good and with inacceptable intubation conditions. We included only patients who received propofol as premedication. Future studies that use other sedative drugs are needed to further evaluate the IRS, which would increase the generalizability of our findings. In our study, IRS 3 and IRS 4 were both hypothesized to predict sufficient sedation for the intubation procedure. Therefore, we combined both scores in our evaluation. Taking both scores apart, we expected that IRS 4 would better predict sufficient sedation during intubation than IRS 3. However, the results of our study show a nonsignificant higher positive predictive value of IRS 3 compared to IRS 4 (90% compared to 71%, respectively, p = 0.10). This could possibly be explained by the difference in patient numbers in both groups (56 vs. 33) or by the hypothesis that in patients with IRS 4 propofol has already reached its peak effect and by the time intubation is started, the effect is expired. Though we belief that a positive predictive value of 85% makes the IRS certainly suitable for clinical practice, we should seek for methods to further improve this positive predictive value. It might be valuable to combine the motor reaction to heel rubbing with the degree of muscle relaxation. In the original report of Naulaers et al., the level of muscle relaxation was also scored on a 4-point scale (1 = hypertonia, 2 = normal muscle tone, 3 = mild hypotonia, 4 = profound hypotonia). 20 Adding this relaxation score to our IRS could possibly increase the number of patients in whom effective sedation can adequately be predicted before the intubation is started. Using both the sedation and the relaxation score was already done by Smits et al. studying propofol dosing in neonates. 25 They defined sufficient relaxation as mild or profound hypotonia. However, no conclusions about the usability of both scores can be drawn from their results. In this study, we did not determine interrater variability of the IRS. This is an important limitation of this study. Where “spontaneous movements” and “no movement at all” are obvious scores andwill most certainly not lead to much disagreement between clinicians, more disagreement could arise with the items “movement in reaction to touch” and “movement in reaction to a firm stimulus.” Besides this, there could be variation in the meaning of the term “firm stimulus.” Thus, interrater variability in IRS should be determined.