Adverse events and behavioral reactions related to ketamine based anesthesia for anorectal manometry in children

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.

Anorectal Manometry in Children: The Update on the Indications and the Protocol of the Procedure

Anorectal disorders are common in children. They are related to structural and/or functional abnormalities of the anorectum or pelvic floor with a variety of symptoms. Therefore, diagnostic tests to evaluate anorectal function can help to better understand the underlying pathophysiology and aetiology as well as facilitate patient management. During the past decades, substantial efforts have been made to improve anorectal function testing; however, more advanced investigations might lead to difficulties in interpretation. Additionally, a great diversity of equipment and protocols are used among centres, which may lead to heterogeneous interpretation of results. More studies to standardize methods of testing and validate reference values are strongly recommended in children. This review updates on the current indications and the protocol of anorectal manometry.

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.

An ANMS-NASPGHAN consensus document on anorectal and colonic manometry in children

BACKGROUND

Over the last few years, the study of the colon and anorectal function has experienced great technical advances that have facilitated the performance of the tests and have allowed a more detailed characterization of reflexes and motor patterns. As a result, we have achieved a much better understanding of the pathophysiology of children with defecation problems. Anorectal and colonic manometry are now commonly used in all major pediatric referral centers as diagnostic tools and to guide the management of children with intractable constipation and fecal incontinence, particularly when a surgical intervention is being considered.

PURPOSE

This review highlights some of the recent advances in pediatric colon and anorectal motility testing including indications and preparation for the studies, and how to perform and interpret the tests. This update has been endorsed by the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN).

Anorectal manometry with and without ketamine for evaluation of defecation disorders in children

INTRODUCTION

Anorectal manometry (ARCM) provides valuable information in children with chronic constipation and fecal incontinence but may not be tolerated in the awake child. This study aimed to evaluate the effect of ketamine anesthesia on the assessment of anorectal function by manometry and to evaluate defecation dynamics and anal sphincter resting pressure in the context of pathophysiology of chronic functional (idiopathic) constipation and soiling in children.

METHODS

This was a prospective study of children who were investigated for symptoms of chronic constipation and soiling between April 2001 and April 2004. We studied 52 consecutive children who had awake ARCM, biofeedback training and endosonography (awake group) and 64 children who had ketamine anesthesia for ARCM and endosonography (ketamine group). We age matched 31 children who had awake anorectal studies with 27 who had ketamine anesthesia.

RESULTS

The children in awake and ketamine groups were comparable for age, duration of bowel symptoms and duration of laxative treatments. ARCM profile was comparable between the awake and the ketamine groups with regard to anal sphincter resting pressure, rectal capacity, amplitude of rectal contractions, frequency of rectal and IAS contractions and functional length of anal canal. Of 52 children who had awake ARCM, dyssynergia of the EAS muscles was observed in 22 (42%) and median squeeze pressure was 87mm Hg (range 25-134). The anal sphincter resting pressure was non-obstructive and comparable to healthy normal children. Rectoanal inhibitory reflex was seen in all children excluding diagnosis of Hirschsprung disease.

CONCLUSIONS

Ketamine anesthesia does not affect quantitative or qualitative measurements of autonomic anorectal function and can be used reliably in children who will not tolerate the manometry while awake. Paradoxical contraction of the EAS can only be evaluated in the awake children and should be investigated further as the underlying cause of obstructive defecation in patients with chronic functional constipation and soiling.