Regulation of the cerebral circulation: bedside assessment and clinical implications

Table 3 Cerebral haemodynamics in critical illness

Critical illness	Effect of disease on cerebral haemodynamics			Does the cerebral haemodynamic parameter relate to prognosis?
Critical illness	Flow	Cerebral autoregulation	CO₂ reactivity	Flow	Cerebral autoregulation	CO₂ reactivity
TBI	Decreased [45, 46, 111] then increased [46, 112]	Decreased [44, 113]	Decreased [44, 49, 114, 115]	Yes: decreased [44–46, 111] and increased [44, 112] CBF related to poor outcome	Yes [44, 47]	Most studies find yes [44, 49], while some find no [51]
SAH	Decreased (vasospasm) [14, 55]	Decreased [54, 56]	Decreased [55]	Yes [62]	Yes [60, 62, 116]	Yes [117]
Stroke	Decreased [66, 67, 118]	Decreased [70, 71]	Decreased [68, 69]	Yes [66, 67]	Yes [71]	Yes [69]
Sepsis	Unchanged [78, 81], or decreased [5]	Unchanged [82], decreased [78, 79], or increased [83, 84]	Unchanged [82] or decreased [77]	Unknown	Unknown	Unknown
Preterm infants	Decreased [87, 89, 119]	Unchanged [93] or decreased [87, 88]	Decreased [88, 90]	Yes [119]	Yes [88, 95, 120]	Yes [88, 90]

CBF cerebral blood flow, CO ₂ carbon dioxide, SAH, subarachnoid haemorrhage; TBI, traumatic brain injury

ISSN: 1364-8535