Bypassing the post-anaesthesia care unit after elective hip and knee arthroplasty: a prospective cohort safety study

Abstract

Following knee and hip arthroplasty, transfer to a recovery area immediately following surgery and before going to ward might be unnecessary in low-risk patients. Avoiding the recovery area in this way could allow for more targeted use of resources for higher risk patients, which may improve operating theatre flow and productivity. A prospective single-centre cohort study on the safety of criteria for bypassing the post-anaesthesia care unit in elective hip and knee arthroplasty was designed. Criteria were: ASA physical status < 3; peri-operative bleeding < 500 ml; low postoperative discharge-score (modified Aldrete-score); and an uncomplicated surgical and neuraxial anaesthesia procedure. The primary outcome was the number of patients in need of secondary readmission to the post-anaesthesia care unit. Events within the first 24 postoperative hours were recorded, along with readmission and complication rates. A total of 696 patients were included, with 287 (41%) undergoing total hip arthroplasty, 274 (39%) undergoing total knee arthroplasty and 135 (19%) undergoing unicompartmental knee-arthroplasty. Of these, 207 (44%) bypassed the post-anaesthesia care unit. Patients all received multimodal analgesia without peripheral nerve blockade. Only one patient in the ward group required secondary readmission to the post-anaesthesia care unit. Within 24 h, 151 events were reported, with 41 (27%) in the ward group and 110 (73%) in the post-anaesthesia care unit group. Two events in each group occurred within 2 hours of surgery. No complications were attributed to bypassing the post-anaesthesia care unit. The use of simple pragmatic criteria for bypassing the post-anaesthesia care unit for patients undergoing knee and hip arthroplasty with spinal anaesthesia is possible and associated with significant reduction of post-anaesthesia care unit admission and without apparent safety issues. Confirmation is needed from other studies and external validity should be interpreted cautiously in centres with different peri-operative regimens, organisational and staffing structures.

Keywords: PACU; enhanced recovery; hip arthroplasty; knee arthroplasty.

Figure 1

Patient flow diagram for included and excluded patients and their allocation to ward or PACU discharge following surgery. DASAIM: Danish Society of Anaesthesiology and Intensive Care Medicine score (modified Aldrete‐score).

Figure 2

Location, number and time of occurrence of adverse events in patients transferred directly to the general ward or admitted to PACU after elective knee and hip arthroplasty. Events are grouped in time slots 0–2 h, 2–6 h and 6–24 h after surgery, and the location of occurrence of the event is marked either by grey (occurring in the general ward) or black (occurring in the PACU). Patients are discharged continuously over time from PACU onto the ward when ready to discharge, and so the number of patients in each time slot is not constant. A patient can therefore be represented with an event occurring in both the ward and the PACU within the same time slot.