Introduction
ADHF is one of the major causes of peri-partum morbidity and mortality. Immediate management of pulmonary edema in pregnancy includes oxygenation, ventilation and hemodynamic management with diuretics and inodilators. Patients with refractory edema unresponsive to diuretic therapy may be considered for ultrafiltration. The early application of SCUF as a novel therapy in post-partum ADHF is feasible option. It is generally well tolerated and resulted in adequate fluid removal and clinical improvement. We are reporting one such case successfully treated in our ICU.
Case Report
A 25 yr/F full term, second gravida, reported to emergency with labor pain. She complained of mild respiratory distress, severe headache and blurred vision.
She was admitted with working diagnosis of PIH with heart failure. Obstetric team started initial treatment with intravenous Inj. Furosemide, Inj. Labetalol, and Inj. Magnesium sulphate. Labor was induced and patient was put on non-steroidal anti-inflammatory drugs (NSAIDS) and intravenous (IV) fluids following delivery. Respiratory distress gradually increased and oxygen saturation (SpO2) decreased. Urine output was 400 ml over 12 hours despite intensive diuretic therapy. Patient was shifted to ICU with SpO2 - 86% while receiving 6 L/min of oxygen via Hudson mask, blood pressure (BP) 110/88 mmHg and respiratory rate (RR) 32/min.
In ICU, arterial blood gas analysis (ABG) revealed metabolic acidosis with severe hypoxemia (Pao2/Fio2 98).
Chest radiography showed bilateral fluffy opacities while lung ultrasonography (LUS) revealed numerous B lines indicating acute pulmonary edema.
2D Echocardiography showed a left ventricular ejection fraction (LVEF) 35-40% with estimated stroke volume (SV) 40 ml.
Confirmed diagnosis of PIH with ADHF and pulmonary edema was made. Conventional therapy with inodilators and diuretics failed to improve the patient condition. There was also noncompliance of BiPAP with face mask. In view of refractory edema, deteriorating SpO2 and ABG parameters, continuous renal replacement therapy (CRRT) was initiated with the following settings: Mode – SCUF, blood flow rate (QB) 140ml/h, Net fluid removal 400 ml/h for 24 h and periodic saline flush. BiPAP with Helmet as interface, PEEP of 10 cmH2O, pressure support of 15 cmH2O, inflated cushion with 120 cmH2O and a low resistance circuit of length 65 cm with a rise time of 1 millisec was started. EF improved to 60%. SpO2 was maintained at 99% with BNP decreasing to 300 ng/dl and then to 100 ng/ml. Dobutamine was tapered and stopped. The patient became hemodynamically stable, ABG parameters improved, hypoxemia reverted. The patient was weaned off BiPAP in the following 2 days and shifted to ward.
Discussion
The scottish confidential audit of severe maternal morbidity reported acute pulmonary edema as the fourth most common form of maternal morbidity.1 Incidence of acute pulmonary edema in pregnancy vary from as low as 0.08% to as high as 0.5%. It may occur in up to approximately 3% of women with pre-eclampsia with 70% of cases occurring after birth. In the current case the patient developed pulmonary edema after delivery.1 LUS is a simple and effective tool in diagnosing pulmonary oedema at bedside. B lines in lung ultrasound as evidenced by vertical lines till the end of field are due to fluid in interlobular septa. B lines at 7mm shows interstitial edema in inter lobular space and at 3mm indicate alveolar edema. This characteristic was used for early identification of pulmonary edema in our case.2 The surviving sepsis campaign 2016 has suggested the use of dynamic parameters like stroke volume variation (SVV) to monitor fluid responsiveness,3 which was successfully utilized in this case. In CHF, measurement of BNP is useful as strong independent predictor of all relevant clinical outcomes across the whole spectrum of disease severity. It can facilitate diagnosis and guide HF therapy.4 The serial measurement of BNP helped in monitoring the clinical course of the patient.
Helmet (STARMED) is a novel interface better comfort, reducing the local side effects and increase the success rates during continuous positive airway pressure (CPAP) and non-invasive ventilation (NIV). Optimum effectiveness can be achieved with a PEEP of 10 cmH2O, with an inflated cushion of the Helmet with 120-150 cmH2O and a low resistance circuit (22mm ID, 65 cm length, Resistance- 1.6 cmH2O at 1 l/s) and a fast rise time. This significantly increases the pressurization and depressurization rates of the helmet and decreases the inspiratory delay, unassisted efforts and auto-triggering.5 When compared with facemask, helmet has been found to significantly decrease the intubation rates, 90 day mortality and increase in ventilator free days in patients with acute respiratory distress syndrome (ARDS). The higher PEEP tolerated by helmet might be the reason for its success in this subgroup of patients.6
Intravenous furosemide (bolus 20-40mg over 2 min) is used to promote venodilation and diuresis. Even with repeated doses of 40-60 mg (after approximately 30min) if there is an inadequate diuretic response (maximum dose 120mg/h), it is considered as diuretic resistance.7 In decompensated HF, ultrafiltration safely produces greater weight and fluid loss than intravenous diuretics and is an effective alternative therapy.8 UF for CHF is usually reserved for patients with renal failure or those unresponsive to pharmacological management. In RAPID-CHF trial, fluid removal and weight loss after 24 h was significantly higher in the UF group as compared to usual care groups.9
2016 ESC guidelines for diagnosis and management of patient in acute heart failure placed SCUF in Class IIb Level B recommendation for treatment of any patient with cardiac failure.10 Advantage of SCUF over diuretics are more rapid removal of fluid excess (upto 400ml/h), better improvement in symptoms, higher clearance of sodium load, isotonic fluid removal, decreased risk of electrolyte abnormalities (i.e. hypokalemia). In this case, SCUF was initiated after 3 hours of diuretics as the same did not improve the condition.