Effects of sevoflurane and enflurane on lower esophageal sphincter pressure and gastroesophageal pressure gradient in children

Anesthesia for peroral endoscopic myotomy in Japan

PURPOSE OF REVIEW

Peroral endoscopic myotomy (POEM) was developed in Japan as a less invasive treatment for esophageal achalasia requiring general anesthesia under positive pressure ventilation. In 2018, the Japan Gastroenterological Endoscopy Society published the first guidelines describing the standard care for POEM. Based on these guidelines, we discuss the typical approach to anesthesia during POEM for the management of esophageal achalasia in Japan.

RECENT FINDINGS

Prior cleansing of the esophagus is essential to prevent both aspiration during induction of anesthesia and contamination of the mediastinum and thoracic/abdominal cavity by esophageal remnants after endoscopic resection of the esophageal mucosa. Although rare, adverse events related to intraoperative carbon dioxide insufflation occur. These are treated through percutaneous needle decompression and insertion of a chest drainage tube for pneumoperitoneum and pneumothorax, respectively. Caution should be exercised regarding the development of subcutaneous emphysema and its involvement in airway obstruction.

SUMMARY

Prevention of aspiration pneumonia and adverse events related to the insufflation of carbon dioxide is essential in the management of esophageal achalasia through POEM. Close cooperation between gastrointestinal endoscopic surgeons and anesthesiologists is indispensable in POEM.

Effects of Anesthesia on Pediatric pH Impedance

OBJECTIVES

Anesthesia can alter gastric and small intestinal motility, but its effect on gastroesophageal reflux (GER) is unclear. We set out to evaluate the effect of anesthesia on pH-multichannel intraluminal impedance (pH impedance) evaluation of GER.

METHODS

Retrospective single-center analysis of 95 pH impedance probe studies performed in patients both with anesthesia exposure and esophagogastroduodenoscopy (n = 50) and without (n = 45).

RESULTS

Increased acid reflux per hour, nonacid reflux per hour, and total reflux per hour were observed in the first 4 hours, both overall and in children 1 year or older and in both sedation groups. This difference remained for the older children without sedation by multiple regression analysis for nonacid reflux per hour and total reflux per hour. Patients using proton pump inhibitors had more nonacid reflux events per hour and total reflux events per hour regardless of sedation.

CONCLUSIONS

Based on the results of the present study, there is no need to eliminate the data collected immediately after placement of the probe in children younger than 1 year of age, but in those who are 1 year or older without sedation, there may be a greater number of reflux events in the first 4 hours. The first 4 hours, therefore, should be carefully evaluated in patients older than 1 year of age. Further study is needed to provide normative data for the first 4 hours versus the later time period, both for those undergoing sedation and for unsedated patients, to validate the findings from the present study and to better understand the mechanism of GER.

Anesthetic management of peroral endoscopic myotomy for esophageal achalasia: a retrospective case series

Peroral endoscopic myotomy (POEM) is a newly developed, less invasive treatment for esophageal achalasia that requires general anesthesia under positive pressure ventilation. In this retrospective case series, we describe the anesthetic management of 28 consecutive patients who underwent POEM for esophageal achalasia. Anesthesia was maintained with sevoflurane and remifentanil under positive pressure ventilation through a tracheal tube. Retained contents in the esophagus were evacuated just before anesthesia induction to prevent regurgitation into the trachea. The POEM procedure was performed using an orally inserted flexible fiberscope. Elevation of end-tidal carbon dioxide after initiating esophageal carbon dioxide insufflation was observed in all patients and was treated by minute adjustments to the ventilation volume. Scopolamine butylbromide-induced tachycardia in one patient was treated with landiolol hydrochloride, which is a short-acting beta 1-selective blocker. Minor subcutaneous emphysema around the neck was observed in one patient. POEM was successfully completed, and tracheas were extubated immediately after the procedure in all patients. Our findings suggest that prevention of aspiration pneumonia during anesthesia induction, preparation for carbon dioxide insufflation-related complications, and treatment of scopolamine butylbromide-induced tachycardia play important roles in safe anesthesia management of POEM for esophageal achalasia.

Anesthetic management of a child with Aicardi syndrome undergoing laparoscopic Nissen's fundoplication: a case report

Aicardi syndrome (AS) is a rare congenital syndrome and is characterized by the triad of infantile spasm, agenesis of the corpus callosum, and anomaly of chorioretinal lacunae. We here report a case of a patient with AS under general anesthesia. Although there is no report in which muscle relaxants were used in AS patients, vecuronium bromide was used for artificial pneumoperitoneum in this case. Careful management is important for AS patients during an operation that significantly affects respiratory function. In addition, it is possible that muscle relaxants be administered safely in AS patients. Careful monitoring such as epileptiform electroencephalogram and bispectral index monitors may be needed for the early detection of epileptic activities.

The yield of a continuously patent gastroesophageal junction during upper endoscopy as a predictor of esophagitis in children

BACKGROUND AND AIMS

Over the last years we have noted an association between the endoscopic finding of a continuously patent gastroesophageal junction (GEJ) throughout the procedure and macroscopic or microscopic esophagitis. We could not find documentation for these endoscopic findings as a predictor of esophagitis in the literature. We aimed to find an association between these findings and microscopic and macroscopic esophagitis.

METHODS

During upper endoscopy, we routinely observe the GEJ for about 60 s and note the behavior of the GEJ and esophageal contractions. Patients with a persistently patent GEJ were recorded. A group of patients referred for upper endoscopy for reasons other than suspected reflux, whose esophagus was normal, and patients with reflux symptoms served as a control groups.

RESULTS

We found 21 patients (3.0%) in whom a patent GEJ had been noted. No significant age differences were noted between study and control groups. Eighteen out of 21 patients (86%) in the study group had varying degrees of microscopic esophagitis ranging from mild to severe (ten with mild esophagitis, three with moderate esophagitis, and five with severe esophagitis). Interestingly, ten out of 18 (55%) study patients with esophagitis on biopsies had no evidence of additional esophageal abnormality. Although all control patients had a normally appearing esophagus on upper endoscopy, 8/26 (31%) had mild esophagitis on biopsies. Differences were statistically significant (p < 0.001).

CONCLUSIONS

A continuously patent GEJ predicts quite accurately the presence of esophagitis in biopsies and may serve an additional endoscopic finding for the diagnosis of esophagitis especially non-erosive GER.

Pharmacological dissection of the human gastro-oesophageal segment into three sphincteric components

Quantifications of gastro-oesophageal anatomy in cadavers have led some to identify the lower oesophageal sphincter (LOS) with the anatomical gastric sling-clasp fibres at the oesophago-cardiac junction (OCJ). However, in vivo studies have led others to argue for two overlapping components proximally displaced from the OCJ: an extrinsic crural sphincter of skeletal muscle and an intrinsic physiological sphincter of circular smooth-muscle fibres within the abdominal oesophagus. Our aims were to separate and quantify in vivo the skeletal and smooth muscle sphincteric components pharmacologically and clarify the description of the LOS. In two protocols an endoluminal ultrasound-manometry assembly was drawn through the human gastro-oesophageal segment to correlate sphincteric pressure with the anatomic crus. In protocol I, fifteen normal subjects maintained the costal diaphragm at inferior/superior positions by full inspiration/expiration (FI/FE) during pull-throughs. These were repeated after administering atropine to suppress the cholinergic smooth-muscle sphincter. The cholinergic component was reconstructed by subtracting the atropine-resistant pressures from the full pressures, referenced to the anatomic crus. To evaluate the extent to which the cholinergic contribution approximated the full smooth-muscle sphincter, in protocol II seven patients undergoing general anaesthesia for non-oesophageal pathology were administered cisatracurium to paralyse the crus. The smooth-muscle sphincter pressures were measured after lung inflation to approximate FI. The cholinergic smooth-muscle pressure profile in protocol I (FI) matched closely the post-cisatracurium smooth-muscle pressure profile in protocol II, and the atropine-resistant pressure profiles correlated spatially with the crural sling during diaphragmatic displacement. Thus, the atropine-resistant and cholinergic pressure contributions in protocol I approximated the skeletal and smooth muscle sphincteric components. The smooth-muscle pressures had well-defined upper and lower peaks. The upper peak overlapped and displaced rigidly with the crural sling, while the distal peak separated from the crus/upper-peak by 1.1 cm between FI and FE. These results suggest the existence of separate upper and lower intrinsic smooth-muscle components. The 'upper LOS' overlaps and displaces with the crural sling consistent with a physiological LOS. The distal smooth-muscle pressure peak defines a 'lower LOS' that likely reflects the gastric sling/clasp muscle fibres at the OCJ. The distinct physiology of these three components may underlie aspects of normal sphincteric function, and complexity of sphincter dysfunction.

Influence of halothane, isoflurane, and sevoflurane on gastroesophageal reflux during anesthesia in dogs

OBJECTIVE

To determine whether maintenance of anesthesia with halothane or sevoflurane is associated with a lower incidence of gastroesophageal reflux (GER) than the use of isoflurane in dogs undergoing orthopedic surgery.

ANIMALS

90 dogs.

PROCEDURES

Dogs were evaluated during elective orthopedic surgery. Dogs with a history of vomiting or that had received any drugs that would alter gastrointestinal tract function were excluded from the study. The anesthetic protocol used was standardized to include administration of acepromazine maleate and morphine prior to induction of anesthesia with thiopental. Dogs were allocated to receive halothane, isoflurane, or sevoflurane to maintain anesthesia. A sensor-tipped catheter was placed to measure esophageal pH during anesthesia. Gastroesophageal reflux was defined as an esophageal pH < 4 or > 7.5.

RESULTS

51 dogs had 1 or more episodes of acidic GER during anesthesia. Reflux was detected in 14 dogs receiving isoflurane, 19 dogs receiving halothane, and 18 dogs receiving sevoflurane. In dogs with GER, mean +/- SD time from probe placement to onset of GER was 36 +/- 65 minutes and esophageal pH remained < 4 for a mean of 64% of the measurement period. There was no significant association between GER and start of surgery or moving a dog on or off the surgery table. Dogs that developed GER soon after induction of anesthesia were more likely to regurgitate.

CONCLUSIONS AND CLINICAL RELEVANCE

Maintenance of anesthesia with any of the 3 commonly used inhalant agents is associated with a similar risk for development of GER in dogs.

The effects on the lower esophageal sphincter of sevoflurane induction and increased intra-abdominal pressure during laparoscopy

BACKGROUND

Today sevoflurane is one of the most frequently used volatile anesthetics. The speed of induction can approach that of intravenous anesthetics, and case reports using sevoflurane induction for emergency anesthesia have been published. The purpose of this study in laparoscopic cholecystectomy patients was to investigate the effects of sevoflurane during inhalation induction on the lower esophageal sphincter pressure (LESP) and barrier pressure (BrP). The effects on lower esophageal sphincter (LES) and BrP of increased intra-abdominal pressure during laparoscopy were also evaluated.

METHODS

We recorded LESP and BrP in nine patients using a Dent sleeve device. Recordings were made before and after inhalation induction of anesthesia with 8% sevoflurane, as well as before and after insufflation of CO(2) into the abdomen.

RESULTS

After induction with sevoflurane, LESP (P= 0.039) and BrP (P= 0.020) decreased. Nevertheless, BrP was kept positive in all patients. Insufflation of CO(2) into the abdomen during laparoscopy induced a significant increase in LESP (P= 0.02) and gastric pressure (P= 0.004). However, there was no significant change in BrP (P= 0.66); it increased in four patients and decreased in five.

CONCLUSION

BrP was kept positive in all patients after induction of anesthesia. Therefore, we believe that in combination with cricoid pressure, inhalation induction with sevoflurane might be a safe choice. As the adaptive increase in LESP during laparoscopy was not enough to retain a barrier pressure in all patients, it is important to be aware of the risk of regurgitation throughout the anesthesia.