NIPPV has had limited application in pregnant patients due to the perceived risk of aspiration. The current case series has its own limitations in providing definitive recommendations for the indications for and use of NIPPV in the pregnant patient with ARF. A follow-up well-conducted study would be of great use in determining when and how to use this management approach in pregnant patients with sickle cell disease presenting with ACS.
Obstetric patients with preexisting medical problems are more likely to require intensive-care support than those without preexisting medical conditions.[10
] Sickle cell disease is the most common major underlying chronic medical condition in obstetric patients admitted to our ICU. ACS is believed to be a specific form of acute lung injury that can progress to acute respiratory distress syndrome causing ARF.[11
] Because there are no absolute contraindications to the use of NIPPV and the boundaries for its use continue to expand, we decided to look at the use of NIPPV in pregnant patients with ARF caused by ACS.
Pregnant patients are at risk of aspiration. It is a serious complication of pregnancy and is a frequent cause of indirect obstetric death. All the patients in this series were kept nil per mouth and treated with placement of distal gastric tubes for decompression. None developed aspiration pneumonia.
Young adults have a lower incidence of ACS, but it tends to be more severe and is often fatal.[12
] Pregnant patients with ACS causing ARF admitted to ICU need aggressive and timely intervention from a multidisciplinary team of physicians to minimize the morbidity and mortality associated with this devastating complication of sickle cell disease. Moreover, acute respiratory failure contributes substantially to maternal morbidity and mortality; it can also harm the fetus by compromising fetal oxygen delivery. Upon follow-up, only one patient had LSCS. Both patients and the babies were alive and healthy at 6 months after delivery.
A significant incidence of right ventricular dysfunction and pulmonary hypertension in asymptomatic patients with sickle cell anemia has been reported.[13
] In the setting of severe, acute lung disease, this quiescent pulmonary hypertension can cause right ventricular dysfunction that is severe enough to cause circulatory compromise. Hypotension is therefore possible. Two of our patients required short course of inotropic support. However, none of the four deteriorated to the extent of requiring invasive mechanical ventilation.
Critical illness in pregnant women poses special challenges. Physiologic changes that affect cardiovascular and respiratory function are normal during pregnancy. Through interaction with preexisting or new co-morbidities, those changes can give rise to life-threatening complications. Always present, too, is the need to consider the effects of both disease and its treatment on fetal development and outcome. In this small case series, the use of NIPPV was found to be safe and successful with good maternal and fetal outcome in pregnant patients with ARF caused by ACS.
Currently there is not enough evidence to support safe use of NIPPV in ARF in a pregnant patient. The current case series provides the best available evidence to support the use of NIPPV in ARF during pregnancy. In closely monitored pregnant patients with ARF, NIPPV seems to have the potential to shorten ICU and hospital stay. A well-conducted randomized controlled clinical trial is required to confirm this finding.