Prospective, Randomized Comparison of Proseal LMA and Endotracheal Tube in Adult Women selected for Elective Laparoscopic Gynaecological Surgery

INTRODUCTION: Dr. Archie Brain developed a new way of linking artificial and anatomical airway, between 1981 and 1987.This new concept called Laryngeal Mask Airway combined the advantages of a non invasive facemask and the more invasive tracheal tube. Originally LMA was recommended as a better alternative to the face mask. 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. Though LMA provided all the above advantages, the risk of gastric distension, pulmonary aspiration of gastric contents and fear of inadequate ventilation acted as a deterrent to the widespread use of LMA. To overcome the above complications, Dr. Archie Brain designed the Proseal Laryngeal Mask Airway (PLMA) in 2000, with modifications designed to enable separation of gastro intestinal and respiratory tract, improve airway seal, enable positive pressure ventilation and diagnose mask displacement. A Drain tube (DT) enables diagnosis of mask misplacement, reduces risk of gastric insufflation, regurgitation, and aspiration of gastric contents. Laparoscopic surgery or more appropriately minimal access surgery is well established since last 2 decades. It is the advances in anaesthesia and laparoscopic instrumentation and techniques that have led to remarkable development in the field of gynaecological surgeries. General anaesthesia with controlled ventilation remains the gold standard technique recommended for laparoscopic surgeries. Endotracheal tube was the preferred technique for GA, but few complications do arise with ETT. PLMA is the new airway device that forms a more effective glottic seal and it facilitates passage of a gastric tube. It probably provides protection against regurgitation and prevents gastric insufflation when correctly placed. With this background this study was conceptualized to compare Endotracheal tube and Proseal LMA for elective laparoscopic gynaecological surgery. AIM OF THE STUDY: To compare the advantages and disadvantages of PLMA and Endo Tracheal Tube (ETT) for General Anaesthesia in women coming for elective laparoscopic gynaecological surgery. MATERIALS AND METHODS: STUDY SETTING AND POPULATION: After obtaining Institutional Ethical committee clearance and patient’s written informed consent, the study was carried out in AOT, Kasthurba Gandhi Hospital, Institute of Social Obstetrics, Chennai from January 2009 to February 2009. The study was conducted in 50 female patients in the age group of 18 years and above belonging to ASA I and II Posted for elective laparoscopic gynaecological surgery. STUDY DESIGN: Prospective, Randomized, Comparative single blinded case control study. STUDY TYPE: Interventional. INCLUSION CRITERIA: 1. Adult women coming for elective laparoscopic gynaecological surgery. 2. Age - 18 years and above. 3. ASA I & II. 4. Who had given valid informed consent. 5. Mallampatti Scores I & II only. EXCLUSION CRITERIA: 1. Severe cardiovascular, Hepatic and Renal disease. 2. Patients with difficult airway. 3. BMI >30 kg/m2. 4. History of Gastro Oesophageal Reflux disease. MATERIALS REQUIRED: 1. Endotracheal tube 7, 7.5 ID sizes. 2. Proseal LMA 3 size. 3. Macintosh laryngoscope. 4. Stop clock. 5. 10ml syringe. OBSERVATION AND RESULTS: This prospective, randomized, comparative, single blinded case control study compares PLMA insertion with endotracheal tube in 50 adult females undergoing elective laparoscopic gynaecological surgery. All data were collected, tabulated and expressed as Mean +/– standard deviation. Appropriate statistical analysis was conducted. All quantitative data were compared using unpaired student’s test. All qualitative data were compared using Chi square test. P values were calculated for all tests. A P values 0 to 0.01 was considered as 1% significant, 0.011 to 0.05 was considered as 5% significant, and >0.05 was considered as not significant. SUMMARY: This Prospective, Randomized, Comparative single blinded case control study evaluate the effectiveness of PLMA over ETT in 50 adult women, ASA I & II, aged 18 years and above undergoing elective laparoscopic gynaecological surgery (Short and long duration) under GA with IPPV. The conclusions deduced from the study are: 1. Both PLMA and ETT were intubated with ease (P = 0.312) 2. First attempt success rate with PLMA and ETT was 21/25 and 25/25 patients respectively. Second attempt success rate with PLMA was 4/25 statistical analysis shows 5% significance may be due to small sample size. 3. Both the techniques had comparable and insignificant difference in intubation time (P = 0.265). 4. No significant gastric distension intra operatively with both PLMA and ETT. No gynaecologist requested passage of gastric tube to deflate the stomach intra operatively. So PLMA provides good oropharyngeal seal and pulmonary ventilation. 5. Both the techniques had no significant difference in SpO2 and EtCO2 before and during peritoneal insufflation. So PLMA is also a good airway device for laparoscopic surgery. 6. Blood staining on PLMA and ETT was comparable and was not statistically significant. 7. Post operative sorethroat and laryngospasm were not statistically significant in both the groups. 8. Haemodynamically there was significant difference between two groups with regard to systolic blood pressure, diastolic blood pressure and mean arterial pressure and PLMA was found to be a better device than ETT in this aspect. Hence, PLMA is an excellent alternative airway device to endotracheal tube in laparoscopic surgery. CONCLUSION: The Proseal LMA is an excellent alternative airway device to ETT in laparoscopic gynaecological surgery with respect to ease of intubation, time taken for intubation, number of attempts for successful placement, gastric distension, pulmonary ventilation, Blood staining of airway and Post operative airway morbidity and a better device with respect to Haemodynamic response