Low flow anesthesia: Efficacy and outcome of laryngeal mask airway versus pressure-optimized cuffed-endotracheal tube.
BACKGROUND
Low flow anesthesia can lead to reduction of anesthetic gas and vapor consumption. Laryngeal mask airway (LMA) has proved to be an effective and safe airway device. The aim of this study is to assess the feasibility of laryngeal mask airway during controlled ventilation using low fresh gas flow (1.0 L/min) as compared to endotracheal tube (ETT).


METHODS
Fifty nine non-smoking adult patients; ASA I or II, being scheduled for elective surgical procedures, with an expected duration of anesthesia 60 minutes or more, were randomly allocated into two groups - Group I (29 patients) had been ventilated using LMA size 4 for females and 5 for males respectively; and Group II (30 patients) were intubated using ETT. After 10 minutes of high fresh gas flow, the flow was reduced to 1 L/min. Patients were monitored for airway leakage, end-tidal CO(2)(ETCO(2)), inspiratory and expiratory isoflurane and nitrous oxide fraction concentrations, and postoperative airway-related complications.


RESULTS
Two patients in the LMA-group developed initial airway leakage (6.9%) versus no patient in ETT-group. Cough and sore throat were significantly higher in ETT patients. There were no evidences of differences between both groups regarding ETCO(2), uptake of gases, nor difficulty in swallowing.


CONCLUSIONS
The laryngeal mask airway proved to be effective and safe in establishing an airtight seal during controlled ventilation under low fresh gas flow of 1 L/min, inducing less coughing and sore throat during the immediate postoperative period than did the ETT, with continuous measurement and readjustment of the tube cuff pressure.
El-Seify
Zeinab A
ZA
Department of Anesthesia, Doha Clinic Hospital, Doha, Qatar.
Khattab
Ahmed Metwally
AM
Shaaban
Ashraf
A
Radojevic
Dobrila
D
Jankovic
Ivanka
I