Keywords : Laryngeal mask airway, Cuffed OroPharyngeal airway. 1. M.D. ..... positioning of the mask behind the laryngeal opening at the level of C2-3.
194 Indian J. Anaesth. 2003; 47 (3) : 194-197
INDIAN JOURNAL OF ANAESTHESIA, JUNE 2003 194
A COMPARATIVE STUDY BETWEEN THE CUFFED OROPHARYNGEAL AIRWAY AND THE LARYNGEAL MASK AIRWAY IN SPONTANEOUSLY BREATHING ANAESTHETIZED ADULTS. Dr. Indula D. Panchal 1 Dr. Aparna R. Dalal 2 Dr. Chhaya Vasa 3 SUMMARY Aim : The cuffed oropharyngeal airway (COPA), a modified Guedel airway, was compared with laryngeal mask airway (LMA) during spontaneous breathing anaesthesia. Parameters of comparison were ease of use, physiologic tolerance, haemodynamics and the frequency of clinical problems. Methods : One hundred consenting adult patients were assigned either COPA or LMA for airway management during anaesthesia. Intravenous glycopyrrolate (0.004 mgkg-1) was used for premedication and intravenous midazolam (0.05 mgkg-1) and pentazocine (0.6mgkg-1) for sedation. Intravenous sodium pentothal (5-7mgkg-1) was the induction agent, and the patient was maintained using oxygen, nitrous oxide and halothane. Results : Ease of insertion was similar. More airway manipulations were required with the COPA group. The LMA and COPA required head extension during maintenance in 80% and 100% of cases respectively. Jaw thrust was also required in 24% and 80% cases respectively. There were significantly more airway manipulations during maintenance with the COPA, head tilt about 32% compared to LMA 0%, P0.05. Overall, the total number of patients with any adverse event (major intraoperative, minor intraoperative,
PANCHAL, DALAL, VASA : COPA & LMA IN SPONTANEOUSLY BREATHING PATIENTS : COMPARISON
immediate or next day postoperative) was higher in the LMA group than the COPA group (LMA, 48%, compared with COPA, 20%, P0.05). Even the frequency of sore throat was higher in the LMA 20%, with COPA at 4%. P>0.05; Odds ratio, 0.347), though not significant in this study. In a similar study conducted by R.S.Greenberg and others,2 sore throat was significantly more frequent with the LMA than with the COPA, both in the immediate postoperative period. This is probably due to the fact that the LMA is more deeply inserted into the pharynx than the COPA. The COPA requires positioning of the cuff at the base of the tongue at C1-2 and the LMA requires positioning of the mask behind the laryngeal opening at the level of C2-3. This may have led to the greater frequency of blood on the LMA and more frequent sore throat immediately and one-day after the procedure than with the COPA in other studies. A factor that has been shown to reduce the incidence of sore throat with the LMA is cuff pressure control.6 Pharyngeal morbidity is
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reduced when cuff pressure is limited to 60 cms of H20.7 However, this was not attempted with either device in this study. Multiple attempts at the insertion probably increase the incidence of sore throat with the LMA,8 and were suggested as one of the reasons for sore throat in a previous study with the COPA, although it was not seen in this study. Conclusion Both devices are effective in establishing an airway for spontaneously breathing adults under general anaesthesia. The LMA is associated with better airway quality and fewer manipulations during use, suggesting that it is easier to use. The COPA was associated with less blood on device and sore throat, suggesting that it may cause less pharyngeal trauma. Both devices are easy to insert, tolerated well by patients under general anaesthesia, and not associated with a high frequency or level of major clinical problems. We conclude that with respect to physiologic alterations using the devices and overall clinical problems, the COPA and LMA are equivalent. References 1. COPA TM—Cuffed Oropharyngeal Airway - Improved airway management in spontaneous ventilation. Northampton Mallinckrodt Medical (U.K.) Ltd. 2. Robert S. Greenberg, Joseph Brimacombe, Alison Berry, Victoria Gouze, Steven Piantadosi, Elizabeth Dake. A Randomised Controlled Trial Comparing the Cuffed Oropharyngeal Airway and the Laryngeal Mask Airway in spontaneously breathing anaesthetised adults. Anesthesiology 1988; 88: 4. 3. T.Asai, K. Koga, R. M. Jones, M. Stacey, I. P. Latto, R. S. Vaughan. The Cuffed Oropharyngeal Airway– Its clinical use in 100 patients. Anesthesia, 1998; 53: 810-822. 4. Morikawa S, Safar P, DeCarlo J. Influence of head – jaw position on upper airway patency. Anaesthesiology 1996; 265-79. 5. Boidin M.P. Airway patency in the unconscious patient. Br J Anaesth 1985; 57: 306-10. 6. Burgard G, Mollhoff T., Prien T. The effect of the laryngeal mask cuff pressure on postoperative sore throat incidence.J Clin Anaesth 1996; 8: 198-201. 7. A. M. Berry, J. R. Brimacombe, K. F. McManus, M. Goldblatt. An evaluation of the factors influencing the selection of the optimal size of laryngeal mask airway in normal adults. Anesthesia 1998; 53: 565-570. 8. Keller C, Sparr H.J., Brimacombe J. Laryngeal Mask Lubrication-A comparative study of saline versus 2% lignocaine gel with cuff pressure control. Anaesthesia 1997: 52; 592-6.
