Pre-hospital management of pain associated with an acute sickle cell crisis

Sickle Cell Disease (SCD) is a genetic haematological disorder that can cause acute painful crises of the condition. A mutation in the DNA causes the substitution of a single amino acid in the protein haemoglobin (haemoglobin-S) (Yusuf et al, 2011). Immature red blood cells called stress reticulocytes are released prematurely from the bone marrow (Hebbel, 1997). These stress reticulocytes express surface proteins that promote adhesion, typically used to retain the cell in the marrow. Hebbel (1997) and Bunn (1997) identified that the process of occlusion is two-fold: the stress reticulocytes become adhered to the vessel endothelium slowing blood flow which in turn causes the malformed, sickle-shaped erythrocytes to become clumped, trapped in the microcirculation occluding blood flow through the capillary network. The process of occlusion causes ischaemia and infarction of the distal tissues (Chiang Frenette, 2005). A vaso-occlusive crisis commonly presents as uncontrolled pain to the upper back, arm, chest and pelvis and can occur at any time as well as be provoked by stress, dehydration, altitude change and infection (McClish et al, 2009; Ahmed, 2011). Gladwin (2016) explains that SCD patients can suffer from severe complications due to the occlusion of micro-vessels. These complications include chronic kidney injury, acute chest syndrome as a result of infarction of the lung parenchyma, priapism, splenic sequestration, and cerebrovascular infarctions that contribute to the premature mortality that the disease causes (Platt et al, 1991; Manwani Frenette, 2013; Gladwin, 2016). This paper will examine the current analgesic pharmacotherapies available to paramedics attending patients with pain associated with a vaso-occlusive crisis (VOC). Current evidence will be reviewed and contrasted to make recommendations for further pharmacological agents for the management of intractable pain.