A Multi-center Randomized Clinical Trial About Using LMA or ETI in Elderly Patients

Effectiveness and Pulmonary Complications of Peri-Operative Laryngeal Mask Airway Used in Elderly Patients(POLMA-EP Trial): a Multi-center Randomized Controlled Clinical Trial

Perioperative airway management is a top priority of anesthesiologists in daily work, and endotracheal intubation (ETI) is considered as the gold standard for providing safe glottic seal,effective ventilation and oxygen supplement during general anesthesia. But ETI related complications such as concomitant hemodynamic responses, damage to the oropharyngeal structures at insertion and postoperative sore throat. Laryngeal mask airway(LMA) for the anesthesia management brings new choice with invasive, lighter cardiovascular reaction and many other advantages, particularly suited to short and minimally invasive surgery. But LMA increased the risk of gastrointestinal reflux aspiration than using ETI and it may resulted in intolerance in high airway pressure, especially in elderly patients with increased lung compliance or reduced airway resistance. Furthermore, LMA could not entirely prevent the occurrence of postoperative sore throat and hoarse.

To sum up, it is necessary to carry out a multicenter clinical trial to clarify the safety of LMA in elderly patients. The investigators protocol will focus on the incidence of postoperative pulmonary complications (PPCs) when applications of LMA and ETI in elderly patients.

1. Introduction 1.1 Background It is essential for peri-operative patients to ensure airway patency and effective ventilation, and respiratory is the most important task in anesthesiologist's daily work. Endotracheal intubation(ETI) is the gold standard for maintenance patients' ventilation in general anesthesia. It can effectively send narcotic gas into the trachea and allow oxygen ventilation well controlled. However, ETI-related complications such as dental and oral soft tissue injury, intubation and extubation related cardiovascular reactions, hinder its application in some special populations such as elderly patients. Clinical application of laryngeal mask airway (LMA) has brought new options and new ideas for anesthesia management. LMA has the advantage of light damage, small trauma, simple operation and minor cardiovascular response, and it is especially suitable for airway control of patient in short and minimally invasive operation. In recent years, the application of LMA has a greater proportion compared with ETI in some areas. But with LMA application increasing, more and more problems have been reported.

LMA has a greater risk of gastrointestinal reflux and aspiration, because of its inadequate airway tightness. For the same reason, LMA is of intolerance to high airway pressure, and this may lead to hypoventilation in elderly patients with lung compliance or increased airway resistance. At the same time the LMA can't completely prevent incidence of postoperative sore throat and hoarseness. Therefore, it is necessary to carry out a multi-center clinical trial to clarify the peri-operative advantages and disadvantages of LMA to elderly patients, to preliminary explore the LMA complications occurred in elderly patients using predictive models, and to clarify the safety of the LMA in airway support of elderly patients.

1.2 Research Aims The aim of the present research is to study the effects of LMA compared with conventional ETI on elderly patients considering postoperative pulmonary complications, anesthesia and recovery quality, oxygenation and airway support related complications.

1.3 Primary endpoint events Postoperative pulmonary complications before discharge. 1.4 Secondary endpoint events and other pre-specified outcomes 1.4.1 Mortality 1.4.2 PACU stay 1.4.3 Hospiitalization cost and duration 1.4.4 ICU admission and stay time (patients who meet the ICU inclusion criteria are admitted into ICU, those who are admitted into ICU because of bed conversion are excluded, and those who should have been out of ICU are also excluded) 1.4.5 Treatment for PPCs 1.4.6 Blood and sputum culture

Inclusion Criteria:

• Age ≥ 70
• Elective surgery
• BMI ≤ 35 kg/m2
• Provision of signed informed consent

Exclusion Criteria:

• emergency surgery
• have anticipated difficult intubation
• have a broken or unstable cervix
• have laryngeal disease
• are at high risk of aspiration (gastroesophageal reflux disease, full stomach)
• are unable to cooperate for any reason, such as inability to speak or understand, mental disease, or inability to go to the clinics
• have taken experimental drugs in the preceding 3 months or joined another clinical trial
• did not provide informed consent or have withdrawn consent
• are evaluated by the investigator as unsuitable for this trial