A Comparative Evaluation of the Laryngeal Mask Airway - Classic and Tracheal Intubation for Laparoscopic Cholecystectomy

Jayakar, G G (2006) A Comparative Evaluation of the Laryngeal Mask Airway - Classic and Tracheal Intubation for Laparoscopic Cholecystectomy. Masters thesis, Madras Medical College, Chennai.


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INTRODUCTION: Between 1981 & 1987, Dr. Archie Brain developed a new way of linking the artificial and anatomical airways. This new concept, known as the laryngeal mask airway was different from other forms of airway management. Combining the advantages of a noninvasive face mask and the more invasive tracheal tube, the laryngeal mask airway was created to fill an important functional gap that existed between the standard methods of airway control that were in use then. Being the latest in a succession of attempts to fill the gap between the face mask and the tracheal tube, the LMA was initially received with skepticism in the anaesthesia community. Some considered that the facemask and the tracheal tube was all that was necessary for the practice of good anaesthesia whereas for some the LMA was a device exclusively meant for the management of the difficult airway. Originally the device was recommended as a better alternative to the facemask. But ever since its development the LMA has challenged the assumption that tracheal intubation is the only acceptable way to maintain a clear airway and provide positive pressure ventilation. Infact the first clinical series of Dr. Brain included 16 cases of gynaecologic laparoscopy with positive pressure ventilation. Use of the laryngeal mask airway (LMA) during surgery has exploded. Since its commercial introduction in 1988, the LMA is available in 80 countries and has been used in an estimated 150 million surgical procedures. There are now over 2,000 publications pertaining to the LMA. This family of airway devices has proven to be safe for patients not requiring endotracheal intubation, who are not at increased risk of gastric regurgitation and occasionally life-saving in the management of airways of patients who are unexpectedly difficult to ventilate and/or intubate. Though the LMA has provided the convenience of "hands-free" anaesthesia, for some anaesthesiologists the combination of LMA and positive pressure ventilation evokes fear of gastric distension, pulmonary aspiration of gastric contents and inadequate ventilation. Early publications strongly emphasized careful patient selection, and avoidance of agents or settings that may place the patient at greater risk of regurgitation. AIM OF THE STUDY: The aim of the study was to evaluate the effectiveness of LMA- Classic compared to Endo tracheal tube during laparoscopic cholecystectomy based on the: • Ventilation parameters: oxygen saturation: End tidal carbon dioxide, Minute ventilation, Airway pressure. • Gastric distension. MATERIALS AND METHODS: Study design: This study was a randomized prospective comparative study. Study setting and population: After obtaining institutional ethical committee clearance, the study was carried out in the General Surgery OT, Department of Anaesthesiology, Madras Medical College, Chennai, from October 2005 to March 2006. The study was conducted in 40 adult patients of either sex between the age group of 18- 50 years belonging to ASA status I-II posted for elective laparoscopic cholecystectomy at the Government General Hospital-Chennai. Inclusion criteria: • Adults of either sex. • 18-50 years. • ASA physical status I – II. • Mallampatti class I-II. Exclusion criteria: • H/O hiatus hernia. • Reflux oesophagitis. • BMI (body mass index) >30 kg/m². • Diabetes mellitus. • MPC (Mallampatti classification) > II. • Symptoms related to laryngopharyngeal morbidity. • Musculoskeletal abnormalities affecting the cervical vertebrae. OBSERVATION AND RESULTS: The laryngeal mask airway (LMA) and the endotracheal tube (ETT) were compared based on the following parameters: • Ventilation parameters: Minute ventilation: End tidal carbon dioxide (EtCO2), Oxygen saturation, Airway pressure. • Gastric distension: • Post-extubation problems: Coughing, Vomiting, Breath-holding, Laryngospasm, Brochospasm. • Duration: Insufflation time, Anaesthesia time. The groups were: Study group (GROUP L): LMA. Control group (GROUP E): ETT. The patients in both the groups were compared using students t test (for measured variables) and fischer’s exact test (for discrete variables). Chi square test was used to compare sex differences. SUMMARY: • The comparative evaluation of the LMA- classic with tracheal intubation for laparoscopic cholecystectomy showed no significant difference between the two groups based on the demographic variables. • The LMA group maintained effective oxygen saturation similar to the ETTgroup during pneumoperitoneum showing no significant difference. • The ETCO2 values were within normal limits in both the groups during pneumoperitoneum and baseline, showing no significant difference. • The changes in minute ventilation required for effective pulmonary ventilation during pneumoperitoneum were similar between both the groups. • Similar increases in the airway pressures were seen during pneumoperitoneum in both the groups showing no significant difference. • Significant increase in the gastric distension occurred in the LMA group during pneumoperitoneum. • There were no significant differences between the two groups based on the duration of the procedure. • Regarding events related to extubation/ LMA removal there were no significant differences between the two groups. CONCLUSION: In spite of the increase in airway pressure during laparoscopy, laryngeal mask airway provides adequate pulmonary ventilation maintaining oxygen saturation and effective elimination of carbon dioxide similar to endotracheal tube. However in the face of an increased airway pressure and increased minute volume requirements, significant gastric distension occurs with the laryngeal mask airway during laparoscopy. Hence the laryngeal mask airway may not be a safe alternative to tracheal intubation for laparoscopic cholecystectomy.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Laryngeal Mask Airway ; Classic and Tracheal Intubation ; Laparoscopic Cholecystectomy.
Subjects: MEDICAL > Anaesthesiology
Depositing User: Subramani R
Date Deposited: 16 Apr 2018 17:26
Last Modified: 16 Apr 2018 17:26
URI: http://repository-tnmgrmu.ac.in/id/eprint/7028

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