The role of magnesium sulfate in tracheal intubation without muscle relaxation in patients undergoing ophthalmic surgery.
BACKGROUND
Muscle relaxant agents usually use to facilitate tracheal intubation; however, sometimes limitations exist. Magnesium (Mg) sulfate is a candidate for muscle relaxant substitute. This study was designed to determine the effect of Mg sulfate accompanied with propofol and fentanyl in patients undergoing ophthalmic surgery.


METHODS
In a double-blind randomized protocol and before tracheal intubation, Mg sulfate 40, 45, or 50 mg/kg in 100 ml of saline (Groups 1-3, respectively) or saline alone (Group 4) were administrated intravenously in 100 patients (n= 25 in each group) with the American Society of Anesthesiologist (ASA) physical Status I, II, or III. The patients' intubation condition in all subjects were determined and described.


RESULTS
The patients' demographic data including age, ASA, systolic and diastolic blood pressures, intraocular pressure, and body mass index were not significantly different between the groups. A better mask ventilation feasibility in Mg sulfate 45 group (Group 2) was observed when compared with Mg sulfate 50 (Group 3) (P= 0.022) and saline group (Group 4) (P= 0.021). In addition, the vocal cord movement and muscle relaxant requirement in saline group were significantly different from others groups (P< 0.05). The laryngoscopic time in saline group was greater than other groups significantly (P< 0.0001).


CONCLUSIONS
Intravenous administration of Mg sulfate accompanied with propofol and fentanyl facilitates the tracheal intubation without neuromuscular blocking agents. To avoid Mg level increasing in plasma; however, the low dose of Mg sulfate is suggested.
Water and Electrolytes Research Center, Isfahan University of Medical Sciences, Isfahan, Iran; Anesthesiology and Intensive Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Anesthesiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
Hassan-Ali
HA
Soltani
Anesthesiology and Intensive Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Anesthesiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
Seyed Jalal
SJ
Hashemi
Anesthesiology and Intensive Care Research Center, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Anesthesiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
Kamran
K
Montazeri
Department of Ophthalmology, Isfahan University of Medical Sciences, Isfahan, Iran.
Alireza
A
Dehghani
Water and Electrolytes Research Center, Isfahan University of Medical Sciences, Isfahan, Iran; Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
Mehdi
M
Nematbakhsh
Anesthesia; magnesium sulfate; tracheal intubation