A Clinical Study Of Gastric Antrum Sonography In Enhanced Recovery After Surgery Of Airway Safety

Background and ObjectivesGastric aspiration is a serious anesthetic complication that can lead to severe pneumonia and even death.In 1946,Mendelson Syndrome was described for the first time,it is a condition during which a small amount of particularly acidic gastric fluid?pH<2.5?is aspirated,and thereafter led to acute inhaled pulmonary edema,severe cyanosis,asthmatoid dyspnea.Reflux is the movement of fluid and/or food from the stomach up into the esophagus and aspiration is the entry of material from stomach into trachea.With the development of clinical anesthesiology and popularization of general anesthesia,the number of aspiration rises.Risk factors for aspiration during general anesthesia includes relaxed esophageal sphincter,reduced self-protective reflex and bucking during intubation and extubation.Therefore,it's worth every anesthesiologist's attention on the subject of reducing perioperative reflux and aspiration.Strict preoperative fasting which can reduce gastric residual volume and measures which can reduce gastric insufflation help to reduce intra-gastric pressure are important for the protection of patient safety.Currently,the most popular overnight fasting method in China is decades old.This traditional fasting method requires fasting for at least 8 hours,and the actual fasting time is usually longer due to consecutive operations.Longer fasting can lead to anxiety,thirst,hunger,reduced circulation capacity,unstable circulatory during anesthetic induction,insulin resistance and compromised immune function.With the concept of enhanced recovery after surgery acknowledging,the disadvantages of long fasting are widely recognized by medical field,and reducing fasting time is a hot research topic area.However,whether shortened fasting lead to increased gastric residual volume and aspiration risk needs in-depth studies.Detailed fasting protocol that described the amount,concentration and administration time of preoperative intake is worth investigated.With the development of visualization technology,ultrasound can be used to discriminate internal organs,moreover,previous publications indicated that ultrasound can be used on gastric volume and inlet evaluation.Bedside ultrasound can help evaluate aspiration risk and improve anesthesia safety and controllability.This study aims at investigating the value of ultrasound evaluation of gastric volume and investigating the efficacy of preoperative fasting protocol on first-of-the-day surgery and effective airway management.MethodsPart1,using ultrasound to evaluate cross-sectional area?CSA?,and furtherly discuss safety and feasibility profile of fasting protocol under rapid recovery concept.120 patients that were scheduled for the first surgery of the day were recruited,and were evenly randomized into shortened fasting group and regular fasting group.Patients in the former group were administered 800ml carbohydrate beverage at 8pm-10pm the night before surgery,400ml at 5:30-6:00am the morning of surgery day.Patients in the later group fasts from 10pm the night before surgery.CSA and Perlas semi-quantitative rating level?level 2or above is ascribed as severe?were compared between the two groups.Proper treatment included stomach decompression or delaying surgery were given when necessary and patients'safety were protected.Part 2,to evaluate gastric insufflation using ultrasound and compared SLIPA laryngeal mask airway and endotracheal tube on their influence of gastric volume and postoperative pulmonary complication risks.The effect of SLIPA laryngeal mask airway on gastric inlet,aspiration risk and perioperative pulmonary complication were also investigated.ResultsCompared with traditional fasting group,shortened fasting group was associated with significantly higher CSA,GV and ratio of“dangerous stomach”and shorter sleep duration,lower thirst and hunger score.There were 7 patients with level 2 Perlas semi-quantatitive,they were medically intervented including gastric catheterization before surgery or delayed until the patient was reevaluated as level?1.At last none regurgitation or aspiration occured.Comparison between SLIPA laryngeal mask airway and endotracheal tube:There were no difference in gastric insufflation and SBP,DBP,HR and SpO₂ during anesthesia process at all time points.Laryngeal mask airway was associated with higher PetCO₂ at the end of surgery,lower pH and amount of laryngeal secretion.There was no difference in the rate of blood stain,pulmonary complications,nausea and vomiting,sore throat and hoarseness between the two groups.ConclusionPreoperative ultrasound is effective in gastric residual detection,and therefore reducing risk of aspiration.Under the concept of ERAS,preoperative fasting should be shortened and individually meet patient's physiological needs.Patients?exclude ones with gastrointestinal motility disorder?scheduled for the first surgery of the day should have free access to low-sugar water or water the night before surgery,and less than 250ml 2hours before surgery.Gastric volume should be monitored if allowed.SLIPA laryngeal mask airway does not contribute to higher gastric insufflation and postoperative pulmonary complications compared with endotracheal tube.