Rapacuronium for modified rapid sequence induction in elective Caesarean section: neuromuscular blocking effects and safety compared with succinylcholine, and placental transfer

Abstract

We have compared rapacuronium 2.5 mg kg-1 (n = 20) with succinylcholine 1.5 mg kg-1 (n = 22) in a multicentre, blinded, randomized study in full-term parturients undergoing elective Caesarean section under general anaesthesia. Thiopental 5 mg kg-1 was given i.v. followed by the neuromuscular blocking agent. Sixty seconds later intubation was performed. Intubating conditions, evaluated as excellent, good or poor, were good to excellent in 95% and 91% in the intent-to-treat patients after rapacuronium and succinylcholine, respectively (ns). Mean onset times at the adductor pollicis muscle for rapacuronium and succinylcholine were 80.4 (SEM 14.4) s and 63.9 (5.6) s (ns) while maximum block was 96 (1.9)% and 99 (0.4)%, respectively (ns). Rate of recovery was significantly longer after rapacuronium; times for return of T1 to 25% were 16.9 (1.5) min and 9.6 (1.1) min for rapacuronium and succinylcholine, respectively (P = 0.0004). Maternal side effects included more tachycardia and skin erythema with rapacuronium; no maternal mortality or morbidity, including bronchospasm, occurred in either group. There were no neonatal adverse effects in either group based on: Apgar scores at 1 and 5 min; times to sustained respiration; neuroadaptive capacity scores at 15 min, 2 h and 24 h; and umbilical venous and arterial blood-gas values and acid-base status. At delivery (17.7 (3.2) min), mean maternal plasma concentrations of rapacuronium were 9041.4 (1259.1) ng ml-1 and 506.4 (24.9) ng ml-1 for Org 9488 (the main metabolite). Corresponding values for umbilical venous plasma were 808.0 (92.1) ng ml-1 and 59.1 (6.5) ng ml-1, and for umbilical arterial plasma, 361.4 (56.4) ng ml-1 and 29.7 (4.6) ng ml-1, respectively. Umbilical venous to maternal venous ratios for rapacuronium and Org 9488 were 8.8% (1.3)% and 10.2 (1.7)%, respectively.

Intubating Conditions With Two Different Doses of Rocuronium Bromide for Caesarean Section: A Comparative Clinical Study

“…However, its adverse effects such as muscle fasciculations, post-operative myalgia, rise of intragastric & intra ocular pressures as well as the contraindication in malignant hyperpyrexia in susceptible patients and in hyperkalaemia have paved way for research with alternative agents like pancuronium, vecuronium, ropacuranium etc. [9][10][11] Among the nondepolarisers, the mono quaternary amino steroid rocuronium has been used for rapid sequence intubation and is reported to provide conditions similar to that offered by succinylcholine. [12,13] Rocuronium is a drug with quick onset because of its low potency (ED95-0.3mg/kg -1 ).…”

The new neuromuscular blocking agents: do they offer any advantages?

“…58 They may release histamine. 58 Abouleish, 1 Sparr, 106 Levy, 75 and Szenohradszky 107 all found a decrease in mean arterial pressure after rapacuronium, although none of the events required intervention, nor were the changes statistically signi®cant. Whalley compared 20 patients given rocuronium 0.6 mg kg ±1 with 21 patients given atracurium 0.5 mg kg ±1 and found no differences between groups in the changes in heart rate and arterial pressure, in the 15 min after intubation and before skin incision, from control measurements obtained before induction of anaesthesia.…”

Diaplazentarer Transfer von Anästhetika und Adjuvanzien in Schwangerschaft und Geburtshilfe

“…In klinisch üblichen Dosierungen sind weder für depolarisierende noch für nichtdepolarisierende Muskelrelaxanzien fetale oder neonatale Depressionen beschrieben [1,8,32]. Mutagene oder teratogene Effekte sind bei den klinisch gebräuchlichen Muskelrelaxanzien nicht bekannt [46].…”

“…Das depolarisierende Muskelrelaxans Succinylcholin penetriert nur in sehr geringer Menge die Plazenta [1,12,32]. Nur bei Dosen von mehr als 2 mg/kg KG sind Spuren von Succinylcholin im fetalen Blut nachweisbar [32].…”

“…Nichtdepolarisierende Relaxanzien wie Vecuronium, Rocuronium und Atracurium [1,8,12,16,32] passieren in klinischen Dosen ebenfalls kaum die Plazenta und führen in klinisch üblicher Dosierung zu keiner klinisch bedeutsamen Relaxierung des Neugeborenen [12,16,32].…”