Comparison of the cuffed oropharyngeal airway and laryngeal mask airway in spontaneous breathing anesthesia.

BACKGROUND

The cuffed oropharyngeal airway (COPA) is a modified Guedel airway with a cuff at its distal end and a standard 15 mm connector at its proximal end. This study was performed to determine if the COPA would offer any advantage over the laryngeal mask airway (LMA).

METHODS

Eighty ASA class I to II adult patients scheduled for short elective procedures (less than 1 h) were randomly allocated into two groups. All patients were given atropine 0.01 mg/kg, fentanyl 2 micrograms/kg and propofol 2 mg/kg intravenously for induction of anesthesia. The COPA or LMA was inserted following the loss of eyelash reflex. If the jaw was not relaxed enough for insertion of a COPA or LMA, succinylcholine 1 mg/kg was given to facilitate the insertion. When correctly positioned, the cuff was immediately inflated with an appropriate volume. Gentle positive pressure ventilation was applied before spontaneous breathing resumed. Capnography was used to assess the patency of the airway. Anesthesia was maintained with isoflurane-N2O-O2 until the end of surgery. The success rate, vital signs, and adverse events were evaluated and compared.

RESULTS

The success rate in the LMA group (95%) was higher than the COPA group (85%). The increase in circulatory response after the LMA insertion was greater than that after the COPA insertion (P < 0.05). Nine patients (22.5%) in the LMA group needed succinylcholine to facilitate insertion compared with only two patients (5%) in the COPA group. Additional manipulation was frequently (57.5%) needed after inserting the COPA to maintain the patency of the airways, but none needed so in the LMA group. Two patients had laryngospasms upon removal of the LMA, but none had laryngospasm in the COPA group. The incidence of sore throat in the LMA group was higher than in the COPA group (18% vs. 10%).

CONCLUSIONS

We demonstrated that the COPA could be easily inserted without the need of muscle relaxants in most patients. But the COPA needed airway intervention to provide an effective airway in most patients. Compared with the LMA, the COPA caused less stimulation than the LMA.