CARDIOVASCULAR JOURNAL OF AFRICA • Volume 33, No 5, September/October 2022 AFRICA 275 of hypokalaemia in PE is a mutation in the R563Q of the epithelial sodium channel (β-subunit) in the collecting duct and distal renal tubules of the kidney, leading to constitutive sodium reabsorption, hypertension, reduced plasma renin, decreased aldosterone and hypokalaemia.16 Muscle weakness, which may affect the respiratory system, may result from the hypokalaemia. Furthermore, the unavailability of a rapid-acting antihypertensive drug to treat severe hypertension (BP ≥ 160/110 mmHg) in the primary healthcare clinic was a major concern, which all maternity units must resolve.17 One of the predictors of adverse maternal outcomes in PE is dyspnoea.18 The occurrence of dyspnoea in PE is strongly suggestive of PulmE. The presence of severe hypertension in a patient with PE (particularly in the presence of tachycardia) requires the use of nitroglycerin as an antihypertensive19,20 to enhance venous and arterial vasodilatation. Nitroglycerin is administered as an infusion at a dose of 5 µg/min and the rate may be doubled every three to five minutes to a maximum of 100 µg/min.6 It has the potential to cause methemoglobinaemia. It must be used with caution in a patient who has recently had phosphodiesterase inhibitors. In acute PulmE, there is a sympathetic surge and increased peripheral vascular resistance, and this phenomenon has been termed SCAPE (sympathetic crashing acute PulmE).19 This may explain the effectiveness of nitroglycerin in these patients. Intravenous diuretics and supplemental oxygen therapy are usually required. A low dose of morphine may be helpful6 in cardiogenic PulmE as it reduces preload and to some extent decreases afterload and heart rate but must be used with caution to prevent respiratory depression.21 MgSO4 is used in cases of severe PE to prevent eclampsia (seizures associated with hypertension and proteinuria) but it may also lower BP, albeit temporarily, and could have contributed to the hypotension in the case presented. Of note, contemporaneous administration of MgSO4 and rapid-acting nifedipine (a calcium channel blocker) may cause PulmE in 1% of patients.5 Importantly, the choice and titration of therapy in a patient with PulmE are determined by the clinical condition, results of imaging (such as ultrasonography, echocardiography and chest radiograph), electrocardiography, blood tests including arterial blood gases, and invasive monitoring.22 In mild cases of PulmE, invasive monitoring is not usually required. However, assessment of the pulmonary capillary wedge pressure (PCWP) is essential in severe cases because it provides important information about the cardiopulmonary function. Firstly, the pulmonary venous pressure can be discerned and this is a measure of pulmonary congestion. Secondly, the left atrial and left ventricular filling pressures, which are useful in constructing ventricular function curves necessary for determining the myocardial performance, can be obtained.23 It is only in the absence of significant myocardial dysfunction that a CVP can be used to reliably measure PCWP.23 The measurement of PCWP is superior to CVP monitoring because the differences in the right and left ventricular functions may be detected in conditions such as severe PE, myocardial infarction, valvular disease and sepsis. In these conditions, managing fluid therapy with CVP alone is dangerous. Additionally, a CVP catheter is not used for assessing mixed oxygen tension and cardiac output.23 Nonetheless, a CVP is good for assessing extremes of fluid status and is a good portal for venepuncture and infusing drugs such as inotropes. Invasive monitoring with CVP or PCWP may be complicated by arterial puncture, thromboembolism, pulmonary infarction, catheter knotting, pulmonary artery and pneumothorax.23 Due to these complications, the setting where invasive monitoring should be commenced needs careful consideration. In any patient who requires CVP monitoring and emergency CD, consideration must be given to inserting the CVP catheter in the operating room/theatre to facilitate rapid delivery should the patient’s condition deteriorate. The full capacity required to manage PE with severe features is only obtainable in a hospital with a functional critical care unit. Therefore, patients with PE with severe features should be considered for urgent direct transfer to a hospital with an appropriately staffed and equipped ICU. In the case presented, there was a delay of seven hours before the patient arrived in the tertiary hospital. Unavailability of an intensivist and poor access to basic imaging techniques are challenges that require attention in many LMICs24 to improve the health system.25,26 However, to exclude pulmonary embolism, particularly in LMICs, consideration should be given to the use of the pregnancy-adapted YEARS algorithm, which includes D-dimer levels and the presence of three criteria (haemoptysis, clinical signs of deep venous thrombosis and pulmonary embolism as the topmost diagnosis).27 The presence of one or more criteria with a D-dimer ≤ 50 ng/ml or the absence of the three criteria with a D-dimer ≤ 100 ng/ ml excludes pulmonary embolism.27 Additionally, the failure to assay cardiac enzymes makes it difficult to exclude myocardial infarction. Pre-eclampsia complicated by PulmE is an indication for delivery.28 The use of protocol in managing pregnant women with PulmE is associated with a decreased number of maternal deaths but results in an increased rate of caesarean over vaginal delivery.29 For category one CD, which means that there is an immediate threat to the life of the foetus or mother, the Royal College of Obstetricians and Gynaecologists recommend a decision delivery interval of 30 minutes.30 Unfortunately, this recommendation is difficult to achieve consistently in many hospitals in LMICs, including South Africa.31 Evidence suggests that the limited availability of resources in South Africa delays interventions in critically ill pregnant women.24 In the authors’ clinical experience, expedited attempts are usually made to stabilise pre-eclamptic pregnant patients with PulmE before delivery.29 Regardless, although the index patient’s prognosis was guarded, her prolonged stay in ICU without emergency CD for maternal distress should be considered as sub-standard care. Additionally, after 20 weeks of gestation, the development of cardiac arrest in pregnancy with no return of spontaneous circulation following four minutes of correctly performed cardiopulmonary resuscitation is an indication for peripartum CD. The under-use of this method of resuscitation is a major concern and does raise ethical issues, but continuous professional development activity and practical simulation training have been conducted to improve the awareness and utilisation in the health facility where the patient was managed. There is a need for establishing and staffing multi-disciplinary teams required for managing complicated clinical conditions. In this particular case, there was a need for a team comprising a
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