Occult hypoxia after femoral neck fracture and elective hip surgery.

The incidence of hypoxia after femoral neck and total hip arthroplasty was investigated. In addition, the incidence of preoperative and postoperative delirium was assessed. Oxygen saturation and mental status were tested before and after surgery in patients undergoing surgery for a femoral neck fracture or total hip arthroplasty. Hypoxia was present before surgery in five of 50 patients who underwent total hip replacement and 17 of 50 patients with femoral neck fractures. On Day 1 after surgery, 20 patients who underwent total hip replacement and 36 with femoral neck fractures had hypoxia; on Day 3 after surgery, 12 patients who underwent total hip replacement and 17 with femoral neck fractures had hypoxia. Respiratory recovery was quicker in patients after total hip replacement with 39 who recovered by Day 3 after surgery, compared with 31 patients with femoral neck fractures. Preoperatively, patients with femoral neck fracture had significantly lower mental test scores than did patients who had undergone total hip replacement, and this continued on Day 1 after surgery. However, by Day 3 after surgery, there was no significant difference between the groups. Although the scores for the patients with femoral neck fractures were lower, delirium developed in only three patients with total hip replacements and six patients with femoral neck fracture. Hypoxia after hip surgery, particularly after femoral neck fracture, is common. The incidence of delirium was much lower than reported previously, and it is suggested that supplemental oxygen, when indicated and monitored by pulse oximetry, was the cause for the reduction in delirium.