Cohen et al evaluated risk factors affecting mortality within the week after a surgical procedure. This can help identify patients who may benefit from more aggressive monitoring and management or who may benefit from a change in the surgical plan. The authors are from the University of Manitoba and University of Saskatchewan in Canada.
Patient selection: adult
Parameters:
(1) age of the patient in years
(2) gender
(3) ASA physical status score
(4) type of surgery (see section 31.01, above)
(5) timeliness of surgery (elective vs emergency)
(6) complication in operating room or recovery
(7) type of anesthetic agent(s) used
(8) number of anesthetic agents used
|
Parameter |
Finding |
RO |
|
age of the patient |
< 60 |
1 |
|
|
60 - 79 |
2.3 |
|
|
>= 80 |
3.3 |
|
gender |
female |
0.8 |
|
|
male |
1 |
|
ASA physical status |
1 or 2 |
1 |
|
|
3, 4 or 5 |
10.7 |
|
type of surgery |
minor |
1 |
|
|
intermediate |
1.8 |
|
|
major |
3.8 |
|
timeliness |
elective |
1 |
|
|
emergency |
4.4 |
|
complications |
absent |
1 |
|
|
present |
1.4 |
|
type of anesthesia |
inhalation alone |
1 |
|
|
inhalation with narcotic |
0.8 |
|
|
narcotic with inhalation |
0.8 |
|
|
narcotic alone |
1.4 |
|
|
spinal |
0.5 |
|
number of anesthesia drugs |
3 or more |
1 |
|
|
1 or 2 |
2.9 |
where:
• RO = relative odds, rounded to 1 decimal place
• Length of anesthesia and experience of anesthesiologist had relative odds close to 1 (1.08 and 1.06).
• Table 2 has a factor of year of operation (1975-1979 vs 1980-1984) which would no longer be relevant.
• Complications come in different degrees of severity so 1 risk value may be an oversimplification.
• ASA status 5 should have a greater risk than ASA 4 which should be greater than ASA 3.
cumulative odds of mortality within 7 days of surgery =
= PRODUCT(odds ratios for all of the factors)
Interpretation:
• Some factors (age, gender, ASA physical status, type of surgery) are fixed while others can be changed.
• Different combinations of factors can be tried to identify the method with the lowest risk.
Limitations:
• The study was performed in the late 1980's and the mortality rates may have changed in the interval since.
Specialty: Anesthesiology
ICD-10: ,
