Analgesia and sedation for ventilated newborn infants of low dose remifentanyl infusion
© BioMed Central Ltd 2002
Published: 1 March 2002
The aim of our study is to verify the usefulness of remifentanyl (R) in ventilated newborn (nw) evaluating the analgesic effect and how variation of R infusion maintains a level of analgesia according to different modality of ventilation (MV).
Materials and methods
Eighteen nw were admitted in ICU for RDS, GA > 32, mean weight 2.250 ± 450 g. A modified scale, according to PIPP and Comfort, was used to evaluate 'comfort'. According to the score (S) all patients were divided in three groups: A < 5; B = 5; C > 5. Data were collected at T0 (basal value), T1 (30 min after start infusion), Tn (every 4 hours), T-est (extubation time), and T post-est (30 min after extubation). R infusion was started at 0.25 µg/kg/min to obtain an 'ideal' S 5 ± 1; and was modified to obtain an adequate analgesia during PCV. After 'critical' phase R was reduced, evaluating the mean t to reach an adequate RD (respiratory drive) for weaning. S at this moment was < 5 (max 7). Finally R was stopped and the mean t for extubation was calculated. For all parameters median value and SD were calculated. For HR, BP, PSO2 in A, B, C a Student t test was adopted for the significance (P < 0.005) through the single value at T0 (T0 vs A, T0 vs B, T0 vs C) and also A, B, C (A vs B, A vs C, B vs C).
The mean t of R (T1-Tstop) was 66.94 ± 22 hours, with a mean dose of R 0.146 ± 0.038 µg/kg/min. The mean t to reach comfort (5 ± 1) was 20 ± 13.11 hours (T1-T5) with R 0.17 ± 0.14 µg/kg/min. R was 0.18 ± 0.04 µg/kg/min in PCV with a S of 4 ± 0.63. The mean t, to obtain a RD to change PCV to PAV, was 2.30 ± 0.56 hours with R 0.09 ± 0.04 µg/kg/min, comfort S 5 ± 0.53 referred to all the period of PAV. Stop-Test was 15 ± 3.4 min. The S at Tpost-est was 5.5 ± 1.03. Statistically significant is the fall of HR at T0 vs A (P = 0.003) and T0 vs B (P = 0.002) as a confirmation that an adequate level of analgesia brings a stabilization of hemodynamic changes to pain stimuli. SpO2 increased from T0 vs A (P = 0.005) and T0 vs B (P = 0.001) due to synchronization of the patients to MV since the good level of analgesia was reached.
No adverse effects were observed: low dose of R maintained an analgesia with an assessment of patients to MV. Infusion t did not influence time of extubation. Although the S 5 ± 1 is an hypothetic 'ideal' level of analgesia, we can assess that R could permit, in newborn, to reach a state of comfort during all 'MV therapy' until extubation, when pain stimulus is removed.