Following WWII, the Korean and Vietnam Wars furthered improvements in resuscitation and the treatment of shock:
crystalloid fluids were used increasingly in resuscitation
the benefit of fluids in preventing acute renal failure in hypovolemic shock was acknowledged
later on, it became recognized that an excess of crystalloid fluid led to respiratory difficulty ("wet lung")
anesthetic techniques were developed which included the first commonplace usage of general anaesthesia given with airway protection via an endotracheal tube [4]

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4. Safar, P. (1996). "On the history of modern resuscitation." Critical Care Medicine. 24(2 (suppl)): S3-S11.