Early cardiovascular function and associated hemodynamics in adults with isolated moderate-severe traumatic brain injury: A pilot study

Abstract

BackgroundWhile cardiac dysfunction has been described following traumatic brain injury (TBI), its association with systemic and cerebral hemodynamics is not known. We examined the contemporaneous relationship between early cardiac function with systemic and cerebral hemodynamic parameters after moderate-severe TBI. MethodsBedside transthoracic echocardiography (TTE) and transcranial Doppler (TCD) ultrasonography were performed within 24 h in patients > 18 years with isolated moderate-severe TBI. Systemic hemodynamic parameters were quantified using routine monitoring [heart rate and mean arterial pressures (MAP)] and calculation from echocardiographic data [stroke volume index (SVI), cardiac index (CI), and systemic vascular resistance index (SVRI)]. Systolic dysfunction was defined using TTE as global longitudinal strain (GLS) > -16%. Mean middle cerebral artery velocity (FVm) was the measure of cerebral hemodynamics and quantified using TCD. ResultsAmong 15 patients [mean age 43 ± 13 years, GCS 5 ± 3, 73% male], 15 TTE and 15 TCD exams were performed simultaneously. Five (33%) patients had systolic dysfunction, with significantly worse GLS (median [IQR] −12.1% [−14.1, −12] vs. −19.1% [−19.9, −17.7], p = 0.004). Median (IQR) MAP was 97 (89, 107) mmHg, SVI (29.0 [20.5, 31.0] mL m−2), and CI (2.83 [2.05, 3.10] L/min m−2) were low to normal, while SVRI (2704 dyne sec/cm5 m−2 [2210, 4084]) was normal to high. None of the patients had abnormal TCDs. Higher GLS (reduced systolic function) was associated with lower SVI (r2 = 0.274, p = 0.03) but not other parameters. ConclusionSystemic hemodynamic parameters were consistent with an early catecholamine-excess state. While reduced systolic function was associated with lower SVI, there was no relationship with reduced cerebral perfusion, possibly due to normal MAP.