Evaluation of the McPeek postoperative outcome score in three trials

Abstract

Background

Postoperative outcome of patients is determined by recovery characteristics and self-reported quality of life. The first can be assessed with the McPeek score which values three aspects of recovery: mortality, postoperative critical care and duration of hospitalization.

Materials and methods

We calculated the McPeek score of 669 patients in three trials: (1) colorectal cancer surgery, (2) antihistamine/volume loading in various operations, and (3) cholecystectomy. Beforehand, the average of intensive care unit treatment and duration of hospitalization were determined for the different operations to define McPeek score points. The score was tested on reliability, validity, and sensitivity. In addition, clinical applicability was assessed in a survey.

Results

The score was reliable with similarly distributed score points in the three trials at different institutions. Inter-rater reliability was high (97% overlap). Validity was proven by moderate high correlation to convergent criteria such as complications (trial I to III r=0.43, r=0.38, r=0.60), preoperative American Society of Anesthesiologists class (ASA) (r=0.24, r=0.28, r=0.57), and age (r=0.23, r=0.32, r=0.31). The score was different between patients with and without neoplasms (P<0.001, trial II) and between elective or emergency patients (P<0.001, trial III). In a survey, investigators reported that the score was easy to assess and more comprehensive than four other scores.

Conclusions

The McPeek score values the postoperative outcome on a nonlinear scale. A priori, the average duration of hospitalization and critical care for a specific operation has to be defined. Our validation suggests that it is a reliable, valid, sensitive, and practical instrument for outcome analysis after anesthesia and surgery.

Appendices

Appendix 1: The McPeek recovery score

	Score points
Patient who died:
– in the operating theatre	1
– in the hospital, but after leaving the operating theatre	2
Patient who was discharged alive:
– required a great amount of care after operation in an ICU	4
– required a moderate amount of care after operation in an ICU	5
Patient with a routine recovery:
– had a relatively long postoperative hospitalization	7
– had an average postoperative hospitalization	8
– had a relatively short postoperative hospitalization	9

This score is non-additive; points are assigned on the basis of the most severe event. Patients with optimal recovery were thus given a score of 9. A great amount of care after operation was defined as three or more days on an intensive care unit and a moderate amount of less then three days. A relatively long duration of hospitalization was defined as >17 days in trial I and >12 days in trials II and III, an average duration was 14–17 days in trial I and 8–12 days in trials II and III, and a relatively short duration as <14 days in trial I and <8 days in trials II and III.

Appendix 2: Instruction for determination of the McPeek score

Steps for McPeek classification	Example: trial III
A) Identification of the operations of interest	Laparoscopic cholecystectomy
B) Determination of:
ICU amount (range)	0–3 days
Determination of actual duration of hospitalization (range) for the selected operation	3–10 days
C) Defining ICU treatment as:
Great (4 score points)	>2 ICU days
Moderate (5 score points)	1–2 ICU days
Defining duration of hospitalization
Long (7 score points)	>12 days
Average (8 score points)	12–8 days
Short (9 score points)	<8 days
D) Classification of the patients as defined in step C	2 patients, 2 score points
	6 patients, 4 score points
	12 patients, 5 score points
	9 patients, 7 score points
	18 patients, 8 score points
	31 patients, 9 score points

This score is non-additive; points are assigned on the basis of the most severe event. For example, mortality in the operating theatre is always 1 score point and mortality in the postoperative follow-up period of 30 days is 2 score points.

Appendix 3

A) Definitions of postoperative complications (trial I and III)
Pulmonary dysfunction	Pneumonia, atelectasis, pleural effusion, pneumothorax, embolism—if followed by a therapeutic intervention
Thrombo-embolism	Clinical signs, phlebography, or scintigraphy
Cardiac dysfunction	Heart failure, arrhythmia, myocardial infarction—if followed by a therapeutic intervention
Renal dysfunction	Anuria, increase in serum creatinin >1.5 mg/dl or increase of >0.5 mg/dl in patients with preoperative increased levels
Liver dysfunction	Icterus, increase in bilirubin <1.2 mg/dl or trans-aminases >30% of standard value
Pancreatic dysfunction	S-Amylases >250 mg/dl
Wound infection	Visible pus
Anastomotic leakage (peritonitis)	Clinical signs±purulent or fecal drainage
Ileus	Missing bowel peristalsis >4 days, X-ray signs
Sepsis	Proven infection and 2 of the 4 SIRS criteria:
	Temperature >38 or <36°C
	Heart rate >90 beats/min
	Respiratory rate >20 breaths/min
	White blood cell count >12,000 cells/ml or <4,000 cells/ml
B) Responses to intraoperative events/complications (trial II)
Pulmonary	Hyperventilation (volume, oxygen), fenoterol inhalation, theophylline, endotracheal suction
Cardiac	Vasopressors, volume loading (faster or more), head down position, reduction of enflurane, atropine
Allergic	Corticosteroids, anti-histamines, theophylline, epinephrine