Comparison of volume-controlled and pressure-controlled ventilation during laryngeal mask airway anesthesia in cataract surgery

Abstract

The majority of patients undergoing ophtalmic surgery have underlying cardiovascular diseases due to old age, and because gastric insufflation is one of the complications seen in recovery, in this study we tried to compare two types of ventilation methods. Volume-controlled and pressure-controlled ventilation during general anesthesia with laryngeal mask airway, the most appropriate method in terms of various ventilation parameters should be compared and evaluated Methods: In this study, 80 patients who underwent cataract surgery were randomly entered into the study in terms of inclusion and exclusion criteria and also after obtaining informed consent, and were divided into two groups of 40 and examined. Factors such as the type of anesthesia machine, ventilator settings and the type of laryngeal mask airway used are considered as possible confounding factors, and by standardizing these cases, an attempt was made to neutralize their possible effects. For the first group, volume-controlled ventilation with a tidal volume of 8 ml/kg based on the ideal body weight with a respiratory rate of 8-10 per minute was started. In the second pressure-controlled ventilation group, exactly like the first group, the tidal volume of 8 ml/kg based on the ideal body weight started with a respiratory rate of 8-10 per minute. At intervals of 1, 5, 10 and 20 minutes after the start of anesthesia, the parameters of peak pressure (PPeak), dynamic compliance, expiratory flow volume, Spo2 (pulse oximetry), non-invasive blood pressure and heart rate for all patients were recorded by an anesthesiologist. After the patient became conscious enough to be able to speak, he or she was asked about pain in the epigastrium and around the umblicus, and the patient's answer yes and no was recorded on the questionnaire by an anesthesiologist other than the anesthetist. . Results: In this study, except for patients' height, there was no statistically significant difference between the two groups in comparing gender, mean age, weight and BMI. Comparing the mean ventilation parameters of the two groups, the mean of Ppeak, Tidal Volume in the pressure-controlled ventilation group, the mean of Dynamic Compliance, EtCo2 in the volume-controlled ventilation group were higher than the comparison group. Mean diastolic blood pressure in the twentieth minute was significantly different between the two groups. There was no significant difference between heart rate, mean systolic blood pressure and arterial oxygen saturation in the two study groups. Comparing the stomach pain of the two groups in both groups, only 5 patients reported abdominal pain, which was not statistically significant between the two groups.