Intra-abdominal hypertension in pregnancy: Need for generating more evidence before providing sound clinical management recommendations.

Abstract

Sir, We would like to congratulate Lozada et al for their recently published review on the management of intra-abdominal hypertension/abdominal compartment syndrome (IAH/ACS) in the obstetric population.1 Although the topic is clearly dealt with at a most appropriate time and has clinical implications, we have certain queries. The authors correctly pointed out that previously published data showing raised intra-abdominal pressure (IAP) in obstetric patients are scanty.1 In non-obstetric patients, IAP is known to differ between healthy, postoperative, and critically ill patients. The IAP may also differ between certain subsets of obstetric patients, such as critically ill vs those scheduled for elective cesarean section2 and women with preeclampsia vs those who are normotensive.3 Should these groups have different cut-off values of IAP to define IAH/ACS rather than a single value as suggested by the authors? The authors’ recommendations focus on obstetric patients who are critically ill. However, to our knowledge, all previously published studies, except one,2 used non-critically ill obstetric patients to derive “normal” IAP reference values. Even the risk factors for raised IAP will differ in critically ill women vs those scheduled for cesarean sections. Therefore, separate and specific protocols might be required for managing raised IAP in critically ill vs non-critically ill obstetric patients. Most pertinently, even if IAH is defined at values ≥14 mm Hg in obstetric patients, no previous study has evaluated organ functions along with the level of increased IAP. The rise in IAP is noted to be a result of the gradually enlarging uterus, so representing a compensated physiological change of pregnancy. Perhaps, further research should aim to investigate the correlation of organ functions with IAP to help define a cut-off value for diagnosing IAH/ACS. Furthermore, the technique of measurement of IAP in pregnant patients poses some dilemmas. First, Lozada et al recommend using a supine position for the IAP measurement. However, false elevations in IAP of pregnant patients have been noted in the supine compared with the left lateral tilt position.4 Hence, we wonder what would be the most reliable position for measuring IAP in these women. Second, almost all previous data on IAP in obstetric patients, including those used by the authors to formulate their clinical recommendations, were recorded after establishing a spinal block for cesarean section. Such a block would have aimed to achieve sensory block at least at the level of T6, which can be expected to be associated with paralysis of abdominal muscles, leading to altered wall compliance and changes in IAP. These findings may not be replicable in critically ill patients without a spinal block for whom the recommendations have been made.1 Whether the IAP measurement is performed while a spinal block is in effect should be specified in future research. We compliment Lozada et al for reviewing the published literature in the field and providing clinical recommendations, even though the synthesis of the available data appears to offer more questions than answers.