Role of the Swan-Ganz catheter in the ICUA randomized, controlled trial of the use of pulmonary-artery catheters in high-risk surgical patients.
Sandham JD, Hull RD, Brant RF, Knox L, Pineo GF, Doig CJ, Laporta DP, Viner S, Passerini L, Devitt H, Kirby A, Jacka M
N Engl J Med 2003 Jan 2;348(1):5-14.
abstract (from PubMed)
[Note: this summary was provided by Dr. Corrado Marini]
Patients treated with PAC-guided therapy may have increased mortality. There is controversial evidence surrounding the benefits of PAC-guided therapy in surgical patients.
? Subjects: High-risk surgical patients undergoing either elective or emergency surgical procedures including abdominal, thoracic, major vascular, and orthopedic operations. Patients eligibility criteria included age ? 60 with American Society of Anesthesiologists (ASA) class III or IV in patients scheduled to undergo elective or emergency major abdominal, vascular, thoracic or hip-fracture surgery.
? Intervention: 1994 out of 3803 patients screened were randomized into two groups: a standard-care group (997 patients) and a PAC group (997 patients). Patients in the standard-care group were treated without a PAC, but were allowed to have measurement of central venous pressure. Patients in the catheter group had a PAC inserted before surgery and had treatment guided by physiological end-points, namely, an oxygen delivery index of 550 to 600 ml per minute per square meter and a cardiac index between 3.5 and 4.5 liters per minute per square meter with a mean arterial pressure of 70 mm Hg, a PCWP of 18 mm Hg, a heart rate less than 120 beats per minute, and a hematocrit greater than 27%. The strategy to reach the specific end-points in the PAC group included, in order of priority, volume loading, inotropic therapy, vasodilator therapy, and blood transfusions, if Hct was less than 27%. Clinical data acquired in both groups included New York Heart Association (NYHA) functional class, Goldman Cardiac Risk Index, vital capacity, and forced expiratory volume in one second. Vital status at 6 and 12 months was established by telephone contact in both groups.
? Outcome analysis: The primary outcome was in-hospital mortality from any cause (crude mortality). Secondary outcomes were 6 and 12-months mortality, and in-hospital morbidity. In-hospital morbidity was defined by the occurrence of one of the following events:
? Myocardial infarction defined by the presence of a new Q-wave on ECG or ECG changes with increased CPK-MB fraction or troponin
? CHF assessed on the basis of CXR interpreted by an observer unaware of protocol assignment
? Arrhythmia based on ECG or rhythm strip
? Pneumonia according to CDC criteria
? Pulmonary embolism documented at autopsy or by pulmonary angiography, positive CTPA, high-probability V/Q scan or positive Duplex scan of legs
? Renal failure defined by a 50% increase in creatinine concentration or the need for dialysis
? Hepatic failure defined by a serum bilirubin concentration greater than 34 mmol per liter and an increase in PT > 3 seconds
? Sepsis from the CV or PAC defined by inflammation at the catheter site in association with systemic sepsis and positive blood cultures and positive catheter cultures
The sample size was calculated to provide a > 90% power to detect a difference in mortality rates of 10% and 15% in the two groups, allowing a two-sided alpha of 0.05 (if I understand correctly this assumption, the authors were postulating a treatment effect of 33% because a reduction in mortality from 15% to 10% corresponds to a relative risk reduction of 33.3%). Additional calculations (certainly done after the observation of a mortality of 7.7% in the standard-care group) confirmed a 78% power to distinguish between mortality rates of 5% and 8% (I have checked this value and in fact is correct; it assumes a treatment effect of 37.5%. However if one wished to maintain the 90% power with a two-tailed alpha of 0.05 used in the initial calculation of sample size to detect differences between these two values [8% and 5%] then one would need 1488 patients in each arm of the study). I wonder why the authors were happy to accept this extreme decrease in the power to detect a difference!
No crossover was allowed. Analysis, done with unpaired t-test or Wilcoxon rank-sum test for continuous variables and Fisher?s exact test or chi-square test for proportions, was on an intention-to-treat basis.
- Enrolled patients: 1994 patients were enrolled: 997 in the standard-care group and 997 patients in the PAC-guided therapy group. In the standard-care group 945 patients (94.5%) received the planned therapy as opposed to 932 (94.2%) in the PAC group (p > 0.05). Of note, in the standard-care group 228 patients (22.9%), deemed high-risk surgical patients by the authors, were treated in the ICU with a peripheral IV line only; more importantly, 327 patients (32.8%) in this group were treated with inotropes blindly (either they had a CVP line or had a peripheral IV). The groups were similar with respect age, gender distribution, ASA risk class and procedures. DVT prophylaxis was initiated within 24 hours after surgery in 52.1% of the patients in the standard-care group as compared with 53.7% of those in the PAC group. The physiological end-point of an oxygen delivery between 550 and 600 ml per minute per square meter in the PAC group was reached in 21.0% and 62.9% before and after surgery, respectively.
- In ?hospital mortality: 7.7% in the standard-care group and 7.8% in the PAC group.
- Secondary outcomes:
? 6-month survival: 88.1% [95% CI: 86.0 to 90.1] in the standard-care group as opposed to 88.7% [95% CI 85.3 to 89.5] in the PAC group (p >0.05)
? 12-month survival: 83.9% [95% CI: 81.6 to 86.2] in the standard-care group as opposed to 83% [95% CI: 80.6 to 85.4] in the PAC group (p>0.05)
? Pulmonary embolism: zero in the standard-care group vs. 8 (0.8%) in the PAC group (p=0.004)
? No difference in the other secondary outcome including MI, CHF, arrhythmia, renal failure, hepatic failure, sepsis
Conclusions by the authors
In elderly high-risk surgical patients who undergo elective or emergency major surgery there is no advantage to therapy guided by a PAC as compared to standard care
Journal Club copyright Michael Jacobson, MD 1995-2003. Contents may be reproduced for non-commercial purposes, if source is credited. This website is intended as a discussion forum concerning the medical literature, not as a primary source for general medical information. Comments posted here are the responsibility of those posting them, not of this website. Inclusion here does not imply review or approval by this website.