Dexamethasone concentration affecting rocuronium-induced neuromuscular blockade and sugammadex reversal in a rat phrenic nerve-hemidiaphragm model: An ex vivo study

Impact of intravenous dexamethasone on the initiation and recovery of atracurium in children: A double-blinded randomized controlled trial

BACKGROUND

Chronic steroid intake has been associated with attenuation of neuromuscular block. Despite some promising animal and adult studies, the effect of a single dose of intravenous dexamethasone on neuromuscular blockers is not well established. Thus, the present study aimed to demonstrate the effect of dexamethasone given at the time of induction for the prevention of PONV on the action of neuromuscular blockers in children undergoing elective surgery.

METHOD

After obtaining approval from the Institute Ethics Committee and written informed parental consent, 100 ASA I and II children aged 4-15 years undergoing elective surgery randomized to receive either: 0.15 mg/kg (maximum of 5 mg) of dexamethasone diluted to a total volume of 2 ml with 0.9% saline (n = 50) or 2 ml of 0.9% saline (n = 50) at the time of induction. The time interval between application of atracurium and maximum T1 depression, 25% twitch height recovery of T1, amid 25% and 75% twitch height recovery of T1, amid the 25% twitch height recovery of T1 and recovery of the neuromuscular block to a TOF ratio of 0.9, and in between the initiation of atracurium injection till the recovery of the neuromuscular block to a TOF ratio of 0.9 was defined as onset time, clinical duration, recovery index, recovery time, and total recovery period, respectively, and recorded.

RESULTS

The onset time and recovery index time were lower (1.96 ± 0.39, 8.04 ± 2.14, respectively) with dexamethasone in comparison with saline (2.01 ± 0.51, 8.9 ± 3.4, respectively) but not statistically significant. The clinical duration, recovery time, and total recovery period were similar.

CONCLUSION

Application of a single bolus dose (0.15 mg/kg) of dexamethasone during induction does not attenuate atracurium-induced neuromuscular blockade in children.

Remifentanil does not inhibit sugammadex reversal after rocuronium-induced neuromuscular block in the isolated hemidiaphragm of the rat: an ex vivo study

PURPOSE

Sugammadex is used to reverse neuromuscular block induced by rocuronium or vecuronium by forming a stable complex. If the binding capacity of any substance to sugammadex is large enough, this molecule will displace rocuronium or vecuronium from the complex. For drugs used in anesthesia, the binding affinity of remifentanil for sugammadex was highest. The aim of the current study was to investigate the decrease in the reversal of neuromuscular blockade with sugammadex by complex formation between remifentanil and sugammadex in the model using isolated hemidiaphragm of the rat.

METHODS

Phrenic nerve-hemidiaphragms from 34 male Sprague-Dawley rats were allocated randomly to four groups: 0 or 100 ng/ml remifentanil with equimolar amounts of sugammadex and 0 or 100 ng/ml remifentanil with three-quarter dose of sugammadex. Muscle contraction responses were recorded during the stimulation of the phrenic nerve by train-of-four (TOF) stimulation. Rocuronium was added to the organ bath with or without 100 ng/ml remifentanil until the first height response (T1) of TOF disappeared completely. Then, equimolar amounts or three-quarter dose of sugammadex was added.

RESULTS

Remifentanil has no significant effects on the concentration-response curves of rocuronium. No significant differences were observed in the recoveries of T1 and TOF ratio with time after administration of equimolar amounts or three-quarter dose of sugammadex regardless of the presence of 100 ng/ml remifentanil.

CONCLUSION

Clinical concentration of remifentanil does not inhibit sugammadex reversal after rocuronium-induced neuromuscular block. Sugammadex can be used safely without worrying about the interaction with remifentanil.

Effect of protracted dexamethasone exposure and its withdrawal on rocuronium-induced neuromuscular blockade and sugammadex reversal: an ex vivo rat study

Studies have reported that protracted dexamethasone treatment induces resistance to nondepolarizing neuromuscular blocking agents (NMBAs) and the association with nicotinic acetylcholine receptors in the diaphragm of rats. Here, we investigated the effect of protracted dexamethasone administration on the sensitivity to rocuronium and the recovery profile when reversed by sugammadex; additionally, we observed the recovery period of pharmacodynamic change after withdrawal. Sprague-Dawley rats received daily intraperitoneal injections of dexamethasone or saline for 14 days. On days 1, 3, and 7 after the last dexamethasone treatment (Dexa1, Dexa3, and Dexa7, respectively) or 1 day after saline (control group), the phrenic nerve-hemidiaphragm preparation was dissected for assay. The dose-response curve of rocuronium in Dexa1 was shifted to the right compared to controls, but curves in Dexa3 and Dexa7 were not significantly different. Groups were not significantly different in attaining the train-of-four ratio ≥ 0.9, but the recovery index in Dexa7 was shorter than that in control and Dexa1. Recovery profiles (period of sugammadex reversal) were not correlated with resistance properties but rather with total administered drugs (binding capacity of NMBAs and sugammadex). Protracted dexamethasone exposure induced resistance to rocuronium but seemed to have no effect on sugammadex reversal in the rat diaphragm.