Prevention

Why?

Crises are more common in patients who are not transfused pre-operatively

Patient	Prognostic Factor	Outcome	CER	OR (95% CI)	NNF+ (95% CI)
cholecystectomy  b	not transfused pre-operatively independent	sickle cell crisis at ?30 days	33%	2.79 (1.16 to 6.69)	4 (2 to 30)