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

Abstract

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.

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

“…The unconsciousness of the patient under general anesthesia may therefore explain the majority of the decrease in anal canal resting pressure. Our findings are in line with a recent study which evaluated the effect of propofol on ARM outcomes in 27 children ( 22 ). Although the authors state that propofol did not affect the presence of the RAIR, they describe that in 2 children they were only able to show the RAIR under general anesthesia.…”

“…These findings may have a major impact on the way in which IASA is currently diagnosed. In our No effect on the presence or absence of RAIR (24) Propofol Nonopioid, nonbarbiturate intravenous sedative hypnotic by positive modulation of the inhibitory function of the neurotransmitter g-aminobutyric acid (GABA) through GABA-A receptors Lowers anal canal resting pressure (22,23,27,28) May increase percentage of internal anal sphincter relaxation after balloon distension (22) Sevoflurane A positive allosteric modulator of the GABA-A receptor, an NMDA receptor antagonist, potentiates glycine receptor currents, and inhibits nAChR and 5-HT3 receptor currents.…”

“…In contrast to our study, the authors do not describe a loss in anal canal pressure during ARM under general anesthesia resulting in the inability to measure the RAIR. The loss of anal canal pressure during ARM under anesthesia may be secondary to the combination of: (1) a lower basal resting pressure during sleep ( 21 ); (2) the effect of anesthetics on the muscle activity of both the internal and external anal sphincter ( 23 ); and (3) by the hindrance of anesthetics on the reflex contraction of the external anal sphincter ( 22 ). Given the many combinations of anesthetic drugs used in our study population, it is difficult to draw any firm conclusions on individual effects of different anesthetic drugs on anal canal resting pressure or their effect on the RAIR.…”

“…Given the many combinations of anesthetic drugs used in our study population, it is difficult to draw any firm conclusions on individual effects of different anesthetic drugs on anal canal resting pressure or their effect on the RAIR. Findings of previous studies investigating the effect of anesthetics on anorectal motility are summarized in Table 3 (22)(23)(24)(25)(26)(27)(28). Comparative data of mono-therapeutic studies or randomized controlled trials are needed to investigate effects of specific anesthetics on ARM findings.…”

JPGN and the Year 2022

“…The presence of the rectoanal inhibitory relex (RAIR) during anorectal manometry (ARM) has not been studied in children receiving anesthesia under propofol. The presence of the RAIR in constipated children was not afected while under propofol in this study (10). It was also elicited in uncooperative patients in which the RAIR was not visualized before propofol.…”