Case 8: Hypotension During Microdiscectomy

Abstract

A 16-year-old girl (American Society of Anesthesiologists physical status I [ASA 1]) is scheduled for a bilateral L4–L5 microdiscectomy. Aside from her back complaint, she is healthy with no known allergies. She has donated 1 unit of her own blood. She weighs 67 kg and measures 5 ft 4 in.; her starting hematocrit (Hct) is 35 %. In the operating room, after standard monitoring is placed, she is anesthetized in a routine manner and turned prone for the surgery. Ninety minutes into the surgery, with blood loss estimated to be 200 ml, sudden onset of tachycardia from 76 beats per minute (bpm) to 120 bpm occurs. The blood pressure (BP) decreases from a mean arterial pressure (MAP) of 80 mmHg to 50 mmHg. The surgeon is informed. He sees no evidence of any acute blood loss. The hypotension is treated with ephedrine and 750 ml of albumin with good result. An intraoperative Hct taken after the event is 25 %. As a precaution, a 16-gauge intravenous (IV) line is placed in her external jugular vein, and her right radial artery is cannulated. One hour later, the surgeon finishes the operation. Estimated blood loss per suction bottle is 600 ml, and a repeat Hct is 21 %. The vital signs are stable. The surgeon wants a quick changeover, so he can start his next case.