**8. Special hemodynamic considerations**

Patients who develop burn shock and remain hemodynamically labile despite large volume resuscitation may require additional cardiovascular support. Low cardiac output during the acute post-injury phase is a common component of early "burn shock" [162, 163] and may be more pronounced among geriatric patients [164]. In some cases, inotropic support with dobutamine may be required to maintain adequate systemic perfusion [165, 166]. Vasopressors should be avoided if possible as their vasoconstrictive properties can lead to decreased end-organ perfusion, including skin (and thus elevated risk of the propagation of primary injury or impaired healing of skin grafts) and bowel (e.g., contribution to potential bowel ischemia). This is especially applicable to patients with initial low cardiac output and early multiple organ dysfunction [167]. Patients who do require vasopressor support should undergo close hemodynamic monitoring (MAP, CVP, echocardiography, SvO2). As the patient transitions from the "ebb phase" to the "flow phase" (typically around the 48–72 h mark) of the post-burn state, hemodynamic behavior evolves toward the hyperdynamic profile [168]. As the

hyperdynamic phase begins, cardiac output may exceed 1.5 times that of a normal baseline. Increases in cardiac output entail much greater cardiac work and overall energy expenditure. For these reasons, propranolol is highly efficacious during acute care in burn patients [169]. In fact, long-term propranolol administration initiated in the acute setting decreases cardiac work, decreases lipolysis, improves nitrogen balance, helps restore insulin sensitivity, and mitigates post-traumatic stress disorder [170–173].
