Partial amniotic carbon dioxide insufflation (PACI) during minimally invasive fetoscopic interventions on fetuses with spina bifida aperta

Abstract

PACI seems safe in order to improve visualization of intraamniotic contents during minimally invasive fetoscopic surgery. Nevertheless, continued assessments of its benefits and risks are important.

The effects of partial amniotic carbon dioxide insufflation in an ovine model

“…7 Likely more relevant are the significant fetal changes already occurring at PACI pressures of 15 mm Hg, which is more reflective of average PACI pressures reported in the clinical literature. 7,10,11 It is unknown whether the effects of uterine distension will be similar in humans given the sheep uterus appears more compliant and maybe more susceptible to overdistension. As such, for any given pressure, the results we observed in sheep may overestimate the effects that can be expected in humans.…”

“…Fetoscopic access aims to reduce the uterine incision dimensions and hence lower uterine dehiscence rates to avoid significant maternal morbidity associated with open fetal surgery. [5][6][7][8][9][10][11] The safety of PACI has been debated for many years as early animal experiments demonstrate progressive fetal hypercapnia and acidosis during PACI. [12][13][14][15] However, the relevance of these studies remains unclear in the context of current clinical practice, particularly as recent clinical observations show no obvious evidence of adverse short-term fetal outcomes attributed to PACI.…”

“…[12][13][14][15] However, the relevance of these studies remains unclear in the context of current clinical practice, particularly as recent clinical observations show no obvious evidence of adverse short-term fetal outcomes attributed to PACI. [5][6][7][8][9][10][11] Additionally, while initially preterm premature rupture of membranes (PPROM) rates following PACI for fetoscopic MMC patch repair were very high [6][7][8] (84-100%), more recent experience using heated-humidified PACI in an exteriorized uterus with surgical closure of the access site suggests this to be less of a problem. 10,16 No animal studies have investigated the effect of altering PACI pressures, duration, humidity, or the effect of PACI on fetal membrane ultrastructure.…”

Physiological effects of partial amniotic carbon dioxide insufflation with cold, dry vs heated, humidified gas in a sheep model

“…These safety concerns are based on observations in animal experiments demonstrating fetal hypercapnic acidosis [5][6][7][8] . Yet, human clinical case series have reported no adverse effects of PACI during surgery and immediately after delivery 2,[9][10][11][12] . Invasive fetal monitoring during human fetal surgery is not easy and human data are scarce.…”

Heated humidified carbon dioxide for partial uterine insufflation in fetoscopic myelomeningocele repair: insights from animal model

“…Reports of fetoscopic MMC repair techniques have so far shown neurological outcomes comparable to those found by the MOMS trial, with the additional advantages of a more advanced gestational age at delivery, the possibility of having a vaginal delivery and a reduction in the risk of dehiscence in the hysterotomy scar. The main drawback of adopting these fetoscopic techniques is the attendant use of carbon dioxide (CO 2 ) for uterine insufflation.…”