Comparison of postoperative complication between Laryngeal Mask Airway and endotracheal tube during low-flow anesthesia with controlled ventilation

Ali Peirovifar,Mahmood Eydi,Ata Mahmoodpoor,Samad Ej Golzari,Afsaneh Mohammadi,Mir Musa Mirinezhad

doi:10.12669/pjms.292.2980

Ali Peirovifar, Mahmood Eydi + Show 4 more

Open Access

https://doi.org/10.12669/pjms.292.2980

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Abstract

To compare the postoperative complications between Laryngeal Mask Airway (LMA) and endotracheal tube (ETT) during low-flow anesthesia with controlled ventilation. Eighty adult Patients with ASA class I or II were randomly allocated into two forty-patient groups (ETT or LMA). Cuff pressure was monitored during anesthesia. After high uptake period, fresh gas flow (FGF) was decreased to 1 lit/min and isoflurane set to 1%. Monitoring during anesthesia included non-invasive blood pressure, ECG, ETCO2 and pulse oximetry. System leakage (>100 ml/min), rebreathing and any attempt to increase FGF to overcome the leak were monitored during anesthesia. Later, patients were extubated and transferred to Post Anesthesia Care Unit (PACU). In PACU, the incidence of sore throat, cough, difficulty in swallowing and shivering was monitored for all patients. Leakage was observed in two and three cases in ETT and LMA groups respectively (P>0.05). Postoperative cough, sore throat and difficulty in swallowing were significantly less in LMA than ETT group. No significant difference was observed regarding ETCo2 values between 2 groups. If careful measures regarding insertion techniques, correct LMA position and routine monitoring of LMA cuff pressure are taken, LMA can be used as a safe alternative with lower incidence of post operation complication compared with ETT during low-flow controlled anesthesia with modern anesthetic machines.

Highlights

Low-flow anesthesia has many advantages in term of decreasing atmospheric pollution, economy and better maintenance of airway temperature and humidification.[1,2] Baker in 1994 used following classification for low-flow anesthesia: minimal flow as 0.5-1 lit/min, medium flow as 2-4 lit/ min of FGF and very high-flow as more than 4 lit/ min of FGF.[3]
Leakage was observed in five cases (6.2%), from which two cases were in endotracheal tube (ETT) and three cases in Laryngeal Mask Airway (LMA) groups (P>0.05)
Engelhardt et al showed that pressure controlled ventilation using LMA is an alternative to a cuffed ETT during low-flow circle system anesthesia in children

Summary

Introduction

Correspondence: September 27, 2012 December 22, 2012 December 25, 2012 flow as > 0.5-1 lit/min, medium flow as 2-4 lit/ min of FGF and very high-flow as more than 4 lit/ min of FGF.[3] an appropriate sealing is necessary for low-flow anesthesia especially during controlled ventilation.[4]. Laryngeal Mask Airway (LMA) is regarded as a safer supraglottic airway for general anesthesia compared with endotracheal tubes (ETTs) having an established role on difficult airway and spontaneous ventilation.[5,6,7] the LMA does not provide a watertight seal, it has been used largely during positive pressure ventilation in adults and children.[8,9] Some studies support the concept of safety of using LMA during low-flow anesthesia.[10,11]

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