Influence of Intravenous Propofol Sedation on Anorectal Manometry in Healthy Adults

Impact of anesthesia drugs on digestive motility measurements in humans: A systematic review

BACKGROUND AND PURPOSE

Measurement of gastro-intestinal motility is increasingly performed under general anesthesia during endoscopic or surgical procedures. The aim of the present study was to review the impact of different anesthetic agents on digestive motility measurements in humans.

METHODS

This systematic review was performed using the Medline-Pubmed and Web of Science databases. All articles published until October 2023 were screened by identification of key words. Studies were reviewed if patients had an assessment of digestive motility using conventional perfused manometry, high-resolution manometry, electronic barostat or functional lumen impedance planimetry with the use of inhaled or intravenous anesthetic anesthetic agents (propofol, ketamine, halogens, nitrous oxide, opioids, and neuromuscular blockades).

RESULTS

Four hundred and eighty-eight unique citations were identified, of which 42 studies met the inclusion criteria and were included in the present review. The impact of anesthetics was mostly studied in patients who underwent esophageal manometry. There was a heterogeneity in both the dose and timing of administration of anesthetics among the studies. Remifentanil analgesia was the most studied anesthetic drug in the literature, showing a decrease in both distal latency and lower esophageal sphincter pressure after its administration, but the impact on Chicago classification was not studied. Inhaled anesthetics administration elicited a decrease in lower esophageal sphincter pressure, but contradictory findings were shown on esophageal motility following propofol or neuromuscular blocking agents administration.

CONCLUSION

Studies of the impact of anesthetics on digestive motility remain scarce in the literature, although some agents have been reported to profoundly affect gastro-intestinal motility.

Accuracy of Anorectal Manometry to Detect the Rectoanal Inhibitory Reflex in Children: Awake Versus Under General Anesthesia

OBJECTIVES

Our objective was to investigate if there is a difference in the detection of the rectoanal inhibitory reflex (RAIR) when an anorectal manometry (ARM) is performed awake or under general anesthesia.

METHODS

A retrospective review of ARM studies was performed to identify children who had undergone ARMs both while awake and under general anesthesia. We compared ARM outcomes including the detection of the RAIR and anal canal resting pressure.

RESULTS

Thirty-four children had received ARMs both while awake and under general anesthesia (53% female, median age at first ARM 7.5 years [range 3-18 years]). In 9 of 34 (26%) children the RAIR was solely identified during ARM under general anesthesia and not during ARM while awake. In 6 of 9 (66%) this was unrelated to the balloon volumes used during balloon inflations. In 4 of 34 (12%) children, assessment of the RAIR was inconclusive during ARM under general anesthesia due to too low, or loss of anal canal pressure. In 2 of those children, ARMs while awake showed presence of a RAIR. Anal canal resting pressures were higher during ARM while awake versus ARM under general anesthesia (median 70 [interquartile range, IQR 59-85] vs 46 mmHg [IQR 36-65] respectively, P < 0.001).

CONCLUSIONS

General anesthesia may affect the detection of a RAIR in 2 ways. On the one hand, it may facilitate better visualization in children in whom a RAIR could not be visualized while awake. On the other hand, it may cause a loss of anal canal pressure resulting in an inconclusive test result.

Factors Associated with Difficulty Maintaining Insufflation of the Colon During Endoscopy

BACKGROUND

Insufflation of the colon allows for adequate visualization of the mucosal tissue and advancement of the endoscope during colonoscopy. Most colonoscopies are performed with sedation to mitigate discomfort and enhance the colonoscopy experience for both the patient and the endoscopist.

AIM

We aimed to evaluate factors associated with difficulty maintaining insufflation.

METHODS

A cross-sectional study of individuals undergoing colonoscopy at the Oklahoma City Veterans Affairs Medical Center was performed. Experiencing difficulty maintaining air insufflation during colonoscopy was assessed with a questionnaire completed by the performing endoscopist at the end of procedure. Information regarding procedure times, sedation used, demographics, comorbidities, surgical history, and medications used was extracted from the medical record. A multivariate regression analysis was performed to identify factors associated with difficulty maintaining air insufflation. A P value < 0.05 was considered significant.

RESULTS

996 Patients were included for the analysis. Difficulty with insufflation was reported in 240 (24%) colonoscopies; mean age of 63.8 ± 10.4 years old and 13% were female. Fellow trainees were involved in 669 (67%) colonoscopies. Older age (OR 1.02, P 0.03, CI [1.00-1.04]), diabetes (OR 1.5, 95% CI [1.03, 2.05]), fellow's involvement (OR 2.6. (95% CI [1.68, 4.09]), total procedure time (OR 1.02, 95% CI [1.00, 1.03]), mean number of adenomas (OR 1.05, 95% CI [1.00, 1.09]), and MAC use (OR 2.6, 95% CI [1.80, 3.85]) were independent predictors for difficulty in maintaining air insufflation.

CONCLUSION

Our findings suggest that endoscopists should be cognizant of colon insufflation issues in older, diabetic patients undergoing colonoscopies under deep sedation, particularly if prolonged procedure is anticipated or encountered.

Can Propofol Be Used to Assess the Presence of the Rectoanal Inhibitory Reflex During Anorectal Manometry Studies?

OBJECTIVES

To study changes in intra-anal pressure (IAP) and characteristics of the rectoanal inhibitory reflex (RAIR) during anorectal manometry (ARM) in patients undergoing anesthesia induction with propofol.

METHODS

Prospective study in which ARM was performed at baseline while patients were awake and repeated after propofol-induced anesthesia. We studied IAP and the presence and characteristics of the RAIR before and after propofol.

RESULTS

A total of 27 patients were included (63% male; 9.2 years). Three patients had obstructive symptoms after Hirschsprung disease repair (HSCR), and 24 had intractable constipation. At baseline, the RAIR was present on 21 of 27 patients and absent on 6 of 27. Of the six patients with an absent RAIR, it remained absent in four of six (three known HSCR, and one new diagnosis of IAS achalasia), and two of six had a normal RAIR during propofol. Therefore, RAIR was present in all patients with constipation. The mean resting IAP was significantly lower after propofol. The percentage of IAS relaxation after lower balloon volume inflations was significantly higher during propofol (P < 0.05). No difference was observed over the latency time or the total relaxation time after propofol.

CONCLUSIONS

Propofol can be used to assess the presence of the RAIR during ARM in children who are uncooperative and undergoing other procedures under anesthesia. On the other hand, propofol significantly reduces the resting IAP and increases the percentage of internal anal sphincter relaxation after balloon distention. These findings may impact the interpretation to decide if an intervention is needed, or if there is a possible spinal neuropathy.

Anorectal manometry in children with defecation disorders BSPGHAN Motility Working Group consensus statement

Defecatory disorders in children, including chronic constipation (CC) and fecal incontinence (FI), are common conditions worldwide and have a significant impact on children, their families, and the healthcare system. Anorectal manometry (ARM) and high-resolution anorectal manometry (HRAM) are relatively novel tools for the assessment of anal sphincter function and rectal sensation and have contributed significantly to improving the understanding of the anorectum as a functional unit. ARM has been recognized as the investigation of choice for adults with symptoms of defecation disorders, including fecal incontinence (FI), evacuation difficulties, and constipation. Although it is the gold standard tool in adults, it has yet to be formally accepted as a standardized diagnostic tool in the pediatric age, with limited knowledge regarding indications, protocol, and normal values. ARM/HRAM is slowly becoming recognized among pediatricians, but given that there are currently no agreed guidelines there is a risk that will lead to diversity in practice. The British Society of Paediatric Gastroenterology, Hepatology and Nutrition (BSPGHAN)-Motility Working Group (MWG) therefore has taken the opportunity to provide guidance on the use of ARM/HRAM in children with CC and/or FI.

Effect of propofol on anal sphincter pressure during anorectal manometry

We evaluated the effect of propofol on resting anal sphincter pressure (RP) during anorectal manometry performed under general anesthesia in 20 children with chronic constipation. After propofol bolus administration, there was a significant decrease in the RP in 95% of children from a mean of 51.5 ± 15.3 to a mean nadir of 21.7 ± 10.5 mmHg (P < 0.001). The new postpropofol RP of 47.0 ± 12.4 mmHg was significantly lower compared with prepropofol RP (P < 0.0001). Propofol should be used with caution as an anesthetic agent for anorectal manometry, given the potential for confounding RP measurements.