Conversion from prolonged intravenous fentanyl infusion to enteral methadone in critically ill children

L-NAC reverses of the adverse effects of fentanyl infusion on ventilation and blood-gas chemistry

There is an urgent need for development of drugs that are able to reverse the adverse effects of opioids on breathing and arterial blood-gas (ABG) chemistry while preserving opioid analgesia. The present study describes the effects of bolus injections of N-acetyl-L-cysteine (L-NAC, 500 μmol/kg, IV) on ventilatory parameters, ABG chemistry, Alveolar-arterial (A-a) gradient, sedation (righting reflex) and analgesia status (tail-flick latency assay) in unanesthetized adult male Sprague Dawley rats receiving a continuous infusion of fentanyl (1 μg/kg/min, IV). Fentanyl infusion elicited pronounced disturbances in (1) ventilatory parameters (e.g., decreases in frequency of breathing, tidal volume and minute ventilation), (2) ABG chemistry (decreases in pH, pO2, sO2 with increases in pCO2), (3) A-a gradient (increases that were consistent with reduced alveolar gas exchange), and (4) sedation and analgesia. Bolus injections of L-NAC given 60 and 90 min after start of fentanyl infusion elicited rapid and sustained reversal of the deleterious effects of fentanyl infusion on ventilatory parameters and ABG chemistry, whereas they did not affect the sedative or analgesic effects of fentanyl. Systemic L-NAC is approved for human use, and thus our findings raise the possibility that this biologically active thiol may be an effective compound to combat opioid-induced respiratory depression in human subjects.

Analysis of fentanyl pharmacokinetics, and its sedative effects and tolerance in critically ill children

INTRODUCTION

Fentanyl pharmacokinetic and pharmacodynamic data are limited in mechanically ventilated children. This study aimed to assess the fentanyl pharmacokinetics (PK), the sedation outcome, and the development of tolerance in children receiving fentanyl continuous infusion.

METHODS

This study included children admitted to the pediatric or cardiovascular intensive care unit between January 1 and October 31, 2016, who were >30 days to <18 years of age, receiving ventilatory support via endotracheal tube or tracheostomy, and receiving a fentanyl infusion. Population PK analysis was performed using a nonlinear mixed-effects model. The relationship between initial sedation outcome using State Behavioral Scale (SBS) and fentanyl exposure was assessed, and the observations consistent with tolerance were described.

RESULTS

Seventeen children, with a median age of 0.83 years (range: 0.1-12) and weight of 8.7 kg (range: 3.4-52), were included. The fentanyl PK was adequately described by a weight-based allometry model with the power of 0.75 for clearance (CL=89.8 L/hr/70 kg) and distributional CL, and 1 for volumes of distribution. In infants <6.6 months, age was an additional factor for CL (31.4 L/h/70 kg) to account for age-related maturation. Seven of twelve nonparalyzed patients achieved goal sedation, defined as >80% of SBS scores ≤0 per 24 h, on the first day of fentanyl infusion with a median plasma concentration of 1.29 ng/ml (interquartile range: 0.78-2.05). Eight of the nine tolerant patients developed tolerance within a day of reaching goal sedation.

CONCLUSION

Different weight-based fentanyl dosing rates may be required for infants and children of different ages to achieve similar plasma concentrations. Using SBS scores may guide the dosing titration of fentanyl that resulted in plasma concentrations within the therapeutic range of 1-3 ng/ml. For those who developed tolerance to fentanyl and/or a sedative, it was noted one day after goal sedation was achieved.

Protocolized Sedative Weaning vs Usual Care in Pediatric Critically Ill Patients: A Pilot Randomized Controlled Trial

Aims

The prolonged use of benzodiazepines and opioids can lead to an increase in the incidence of withdrawal syndrome. One of the known risk factors is the lack of a sedative-weaning protocol. This study established a sedative-weaning protocol and compared this protocol with the usual care of weaning in high-risk critically ill children.

Materials and methods

This was an open-label, randomized controlled trial in a tertiary-care hospital. We recruited children aged 1 month to 18 years who had received intravenous sedative or analgesic drugs for at least 5 days. The exclusion criteria were patients who had already experienced the withdrawal syndrome. We established a weaning protocol. Eligible patients were randomly divided into the protocolized (intervention) and usual care (control) groups. The primary objective was to determine the prevalence of the withdrawal syndrome compared between two groups.

Results

Thirty eligible patients were enrolled (19 in the intervention and 11 in the control group). Baseline characteristics were not significantly different between both the groups. The prevalence of the withdrawal syndrome was 84% and 81% of patients in the intervention and control group, respectively. The duration of the initial weaning phase was shorter in the intervention group than in the control group (p value = 0.026). The cumulative dose of morphine solution for rescue therapy in the intervention group was statistically lower than that in the control group (p value = 0.016).

Conclusion

The implementation of the sedative-weaning protocol led to a significant reduction in the percentage of withdrawal days and length of intensive care unit stay without any adverse drug reactions. External validation would be needed to validate this protocol.

ClinicalTrials.gov identifier

NCT03018977

How to cite this article

Tiacharoen D, Lertbunrian R, Veawpanich J, Suppalarkbunlue N, Anantasit N. Protocolized Sedative Weaning vs Usual Care in Pediatric Critically Ill Patients: A Pilot Randomized Controlled Trial. Indian J Crit Care Med 2020;24(6):451–458.

Shortened Taper Duration after Implementation of a Standardized Protocol for Iatrogenic Benzodiazepine and Opioid Withdrawal in Pediatric Patients: Results of a Cohort Study

Supplemental Digital Content is available in the text.

Introduction:

Methadone and lorazepam prescribing discrepancies for the use of iatrogenic withdrawal were observed among providers. A standardized pharmacist-managed methadone and lorazepam taper protocol was implemented at a pediatric tertiary care facility with the aim to reduce the length of taper for patients with iatrogenic withdrawal.

Methods:

A multidisciplinary team of nurses, pharmacists, and physicians reviewed the current literature, then developed and implemented a standardized withdrawal taper protocol. Outcomes were compared with a retrospective control group using past prescribing practices. The primary endpoint was the length of methadone and/or lorazepam taper. Secondary endpoints included evaluation for significant differences between the control and standardized protocol groups regarding additional breakthrough withdrawal medications, pediatric intensive care unit (PICU) and hospital length of stay. We also evaluated provider satisfaction with the protocol.

Results:

The standardized protocol group included 25 patients who received methadone and/or lorazepam taper. A retrospective control group contained 24 patients. Median methadone taper length before protocol implementation was 9.5 days with an interquartile range (IQR) of 5.5–14.5 days; after protocol implementation, it was 6.0 (IQR, 3.0–9.0) days (P = 0.0145). Median lorazepam taper length before protocol implementation was 13.0 (IQR, 8.0–18.0) days; after protocol implementation, it was 6.0 (4.0–7.0) days (P = 0.0006). A statistical difference between PICU length of stay, hospital length of stay, or the number of additional medications for breakthrough withdrawal was not found.

Conclusions:

The use of a standardized withdrawal protocol resulted in shorter taper duration for both the methadone and lorazepam groups. There was no difference in PICU or hospital length of stay.