Laryngeal Mask Airway as a Conduit for Fiberoptic Intubation and Tracheal Evaluation: 2 Cases report / 대한마취과학회지

The laryngeal mask airway (LMA) has several advantages over endotracheal intubation for the airway management in tracheal stenosis patients. Endotracheal tubes are narrower than the natural trachea and can induce reflex airway constriction resulting in more resistance to ventilation. Furthermore, an endotracheal tube can injure the trachea, and cause airway edema, and further tracheal constriction. In contrast, the increase in airway resistance that occurs when using the laryngeal mask is relatively low, because the diameter of the laryngeal mask airway is larger than that of the endotracheal tube and the laryngeal mask airway is not intubated. However, patients with a mechanically obstructed trachea, those with tracheomalacia or an external compression of the trachea, cannot be managed with a laryngeal mask airway, because it cannot prevent tracheal collapse. Thus it is important that the causes of tracheal obstruction are differentiated. This report suggests that the laryngeal mask airway can be used as a route for mechanical ventilation and as a conduit for tracheal evaluation and endotracheal intubation using fiberoptic bronchoscope during tracheal reconstruction surgery in patients with tracheal stenosis.

Effects of Clonidine Pretreatment on Bupivacaine-Induced Cardiac Toxicity Resuscitation in Dogs / 대한마취과학회지

BACKGROUND: Bupivacaine is a amide type local anesthetic agent, widely used for its excellent quality of analgesia and long duration of action. But unintended intravenous injection causes severe complication such as convulsion and cardiovascular collapse, which is known for its difficulty in resuscitation. With all the study, the exact mechanism is still unclear and there are much debate on the method of resuscitation. METHOD: We studied the effect of clonidine pretreatment on bupivacaine-induced cardiac toxicity and resuscitation in anesthetized dog. Twelve dogs were divided into two groups. : saline pretreatment group (control, N=6) and clonidine pretreatment group (clonidine group, N=6). The dogs were anesthetized with N2O-O2-enflurane and vecuronium. Thoracotomy was done in 4th or 5th intercostal space for open cardiac massage. After confirming stability of vital signs, we administered clonidine (10 mcg/kg) or saline, and then administered bupivacaine with the rate of 2 mg/kg/min. When the electeocardiogram showed asystole, 20 mcg/kg of epinephrine was administered via central venous line and open cardiac massage with the rate of 120 beat/min. was performed. We observed electrocardiogram (lead II), arterial blood pressure, heart rate, dose of infused bupivacaine to be required for QRS widening and arrest, required time and administered dose of epinephrine for resuscitation. RESULTS: Clonidine group showed significant decrease of heart rate after pretreatment (p<0.05). There was no significant difference in required dose for QRS widening between two groups. The dose administered for inducing arrest was less in clonidine group than control group (p<0.05). The time required for resuscitation was shorter in clonidine group than control group (p<0.05). The total dose of epinephrine required for resuscitation was less in clonidine group than control group (p<0.05). The blood concentration of catecholamine did not showed significant difference during the whole course of experiment. CONCLUSIONS: Above results demonstrated that clonidine, a central nervous system-mediated sympatholytic agent, facilitated cardiac arrest when bupivacaine was infused intravenously and cardiac rescucitation.