Summary: This case demonstrates the successful use of non-invasive ventilation (NIV) in managing acute pulmonary edema, complicated by altered mentation, severe acidosis, mixed hypercapnic respiratory failure and metabolic acidosis with hyperlactatemia. A 70-year-old female with a history of ischemic cardiomyopathy, diabetes mellitus, hypertension, hyperlipidemia, and previous stroke presented with worsening shortness of breath over two days, which acutely worsened one hour before her Emergency Department visit. Upon arrival, her oxygen saturation was 44% on a non-rebreather mask, and she had an altered mentation (Glasgow Coma Scale E1V1M4). Clinical examination revealed acute pulmonary edema with bilateral lung crepitations and lower limb edema. Arterial blood gas (ABG) showed severe acidosis (pH 6.93), hypercapnia (pCO2 59, pO2 73), low bicarbonate (9), and hyperlactatemia (lactate 12.12). She was started on biphasic positive airway pressure (BiPAP) with an inspiratory positive airway pressure (IPAP) of 15 cm-H2O, expiratory positive airway pressure (EPAP) of 5 cm-H2O, and FiO2 of 100%. Following 40 minutes of NIV, her oxygen saturation and mentation improved (E4V5M6), with significant ABG improvement (pH 7.28, pCO2 32, pO2 311, bicarbonate 16, lactate 7.35). She was admitted to the high-dependency unit, successfully weaned off NIV within 24 hours, and transferred to the general ward the following day. While NIV is essential for managing acute heart failure and pulmonary edema, its use is challenging in patients with severe acidosis (pH < 7.2) and altered mentation. Acidosis can indicate respiratory failure, and altered mentation raises concerns about the patient’s ability to tolerate the NIV mask or protect their airway. However, this case demonstrated that despite these contraindications, careful monitoring led to rapid improvements. This underscores the importance of reassessment soon after NIV initiation, as it can still be effective if improvement is seen, avoiding intubation and improving patient outcomes.
Eshani N. Mathew (Sun,) studied this question.