Sometimes You Have to Revisit the Past to Understand the Present
Muñoz, Elizandro III M.D.†; Pan, Wei M.D.‡
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“… Keats recognized that further long-term advancements with re spect to perioperative risk would require the collaboration of our surgical colleagues. In this month’s issue, Goswami
present such a collaboration.
It is ironic that the American Society of Anesthesiologists, whose members are critical observers of surgical procedures, evolved the best index of “operative risk.” Perhaps the American Surgical Association, whose members are critical observers of anesthetic procedures, will provide us with a meaningful index of “anesthetic risk”.
Arthur S. Keats, ANESTHESIOLOGY, October 19781
OUR knowledge with respect to perioperative risk has come a long way since Arthur Keats’ 1978 editorial.1
Yet, even then with wittingly sharp prescience, Keats recognized that further long-term advancements with respect to perioperative risk would require the collaboration of our surgical colleagues. In this month’s issue, Goswami et al.2
present such a collaboration. Specifically, they present an analysis of prospectively collected perioperative data in 362,767 patients from the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) database in an effort to elucidate the incidence, risk factors, and survival outcomes for intraoperative cardiac arrest (ICA) in adults undergoing noncardiac surgery.
Initiated by the Department of Veterans Affairs in 1991, the NSQIP set out to collect high-fidelity, risk-adjusted perioperative data. Thirteen years after implementation of the NSQIP, their tracking efforts were validated in multiple subsequent outcome studies,3–5
most notably by a reduction in 30-day postoperative morbidity and mortality (43% and 47%, respectively).4
Spurred on by the success within the Veterans Affairs system, the then retitled “ACS NQIP” was expanded to the private sector,5
where it currently incorporates data from more than 400 U.S. hospitals, including 8 of the top 10 hospitals listed in the 2012–2013 U.S. News and World Report’s Best Hospitals.*
The current study by Goswami et al.
utilizing the ACS NQIP has many strengths compared with previous studies that have attempted to address the ICA incidence. Most notable are the large number of subjects (362,767), the homogeneity of the sample population, and the fact that the data were prospectively collected. Statistical analysis was bolstered by forcing relevant patient risk factors for ICA into a logistic regression model, and then stratifying for procedure risk.2
Moreover, the study population was a relatively focused sample, excluding patients receiving cardiac procedures, monitored anesthesia care, peripheral nerve blocks or local anesthesia, trauma, concurrent and transplant cases, adolescents less than 16 yr of age, and American Society of Anesthesiologists physical status VI patients.
Consistent with previously published studies, the authors found the overall ICA incidence to be 7.2 per 10,000 noncardiac surgeries, with a 30-day mortality rate of 63%.2
After multivariable analysis, the amount of intraoperative erythrocyte transfusion was found to be the most important predictor of ICA after noncardiac surgery in adults. Stratified analysis of the ICA risk revealed adjusted odds ratios of 2.5, 7.6, 11.4, and 29.7 for 1–3, 4–6, 7–9, and more than 10 units transfused, respectively.2
Indeed, Goswami et al.
suggest that the number of erythrocytes transfused can be used as a surrogate marker of intraoperative blood loss. Other independent risk factors for ICA included increased age, American Society of Anesthesiologist physical status classification, impaired functional status, and preexistent comorbidities.
Although the authors were unable to demonstrate a temporal correlation between erythrocyte transfusion and ICA,2
transfusion-related acute lung injury, hemolytic transfusion reaction, and transfusion-associated sepsis are known to account for more than 70% of transfusion-related mortality per the U.S. Food and Drug Administration database.9
Similarly, beyond the reduction in death from traumatic bleeding found in the Clinical Randomisation of an Antifibrinolytic in Significant Hemorrhage trial,10
a recent meta-analysis of 129 tranexamic acid trials spanning 10 yr found an overall one-third reduction in the probability of receiving a transfusion and an overall reduction in mortality.11
Despite these data suggesting transfusion-associated perioperative mortality, it is unclear from the current study that the decision for intraoperative transfusion was based on a preexisting anemia as opposed to actual intraoperative bleeding. Forcing the preoperative hematocrit, which is recorded in the ACS NQIP database, into the multivariate logistic regression model in future studies may help further clarify the issue, not only with respect to mortality, but also ICA.
Interestingly, we would like to suggest that the average practicing anesthesiologist in their daily practice might have intuited the primary findings of study by Goswami et al. (e.g., ICA in adults undergoing noncardiac surgery is associated with increased erythrocyte usage, age, American Society of Anesthesiologists physical status, and the presence of preexistent comorbidities). Although these and future data generated from the ACS NQIP database will be extremely helpful in continuing to elucidate the underlying mechanisms of perioperative risk, they also affirm and pay homage to our heritage as perioperative observers, thinkers, and physicians. To quote Charles Vacanti from his 1970 landmark publication in this area (words that could have been transposed into the 2012 article by Goswami, et al.):
The foregoing figures give statistical support to the generally accepted belief that postoperative mortality increases as physical status decreases. While it is to be expected that mortality will be higher in emergency than in elective procedures… in the rush to get the emergency patient into the operating room, a hasty preoperative workup—or none at all—may contribute to the mortality statistics.12
Undeniably, an anesthesiologist’s preoperative impression, their “circling one number on an anesthetic record before
remains to this day, more than 70 yr after its inception, a statistically significant predictor of perioperative risk and ICA.13
Indeed, we came full circle in 2006 when Devenport et al.15
validated the predictive value of the American Society of Anesthesiologists physical status using data from the NSQIP.
In conclusion, we thank the surgeons who in 1991 had the foresight to initiate the NSQIP program in an ongoing effort to collect high-fidelity, risk-adjusted perioperative data, as well as Goswami et al., anesthesiologists who have added momentum to the push for improved patient outcomes. Thus, although the current study echoes and reaffirms findings previously noted in the literature, it is also worth noting, as Keats so eloquently put it in his editorial 34 yr ago, “Progress requires periodic repetition to renew what is forgotten by the sliding scale of memory.” 1
Elizandro Muñoz III, M.D.,† Wei Pan, M.D.‡
†Department of Anesthesiology, Baylor College of Medicine, Houston, Texas. ‡Texas Heart Institute at St. Luke's Episcopal Hospital and Department of Anesthesiology, Baylor College of Medicine. email@example.com
. “Participants.” The American College of Surgeons National Surgical Quality Improvement Program 2012. Accessed July 20, 2012. Cited Here...
1. Keats AS. The ASA classification of physical status—A recapitulation. ANESTHESIOLOGY. 1978;49:233–6
2. Goswami S, Brady JE, Jordan DA, Li G. Intraoperative cardiac arrests in adults undergoing noncardiac surgery: Incidence, risk factors, and survival outcomes. ANESTHESIOLOGY. 2012;117:1018–26
3. Khuri SF, Daley J, Henderson W, Hur K, Demakis J, Aust JB, Chong V, Fabri PJ, Gibbs JO, Grover F, Hammermeister K, Irvin G 3rd, McDonald G, Passaro E Jr, Phillips L, Scamman F, Spencer J, Stremple JF. The Department of Veterans Affairs’ NSQIP: the first national, validated, outcome-based, risk-adjusted, and peer-controlled program for the measurement and enhancement of the quality of surgical care. National VA Surgical Quality Improvement Program. Ann Surg. 1998;228:491–507
4. Khuri SF, Henderson WG, Daley J, Jonasson O, Jones RS, Campbell DA Jr, Fink AS, Mentzer RM Jr, Neumayer L, Hammermeister K, Mosca C, Healey N; Principal Investigators of the Patient Safety in Surgery Study. . Successful implementation of the Department of Veterans Affairs’ National Surgical Quality Improvement Program in the private sector: The Patient Safety in Surgery study. Ann Surg. 2008;248:329–36
5. Khuri SF, Henderson WG, Daley J, Jonasson O, Jones RS, Campbell DA Jr, Fink AS, Mentzer RM Jr, Steeger JE; Principal Site Investigators of the Patient Safety in Surgery Study. . The patient safety in surgery study: Background, study design, and patient populations. J Am Coll Surg. 2007;204:1089–102
6. Braz LG, Módolo NS, do Nascimento P Jr, Bruschi BA, Castiglia YM, Ganem EM, de Carvalho LR, Braz JR. Perioperative cardiac arrest: A study of 53,718 anaesthetics over 9 yr from a Brazilian teaching hospital. Br J Anaesth. 2006;96:569–75
7. Newland MC, Ellis SJ, Lydiatt CA, Peters KR, Tinker JH, Romberger DJ, Ullrich FA, Anderson JR. Anesthetic-related cardiac arrest and its mortality: A report covering 72,959 anesthetics over 10 years from a US teaching hospital. ANESTHESIOLOGY. 2002;97:108–15
8. Sprung J, Warner ME, Contreras MG, Schroeder DR, Beighley CM, Wilson GA, Warner DO. Predictors of survival following cardiac arrest in patients undergoing noncardiac surgery: A study of 518,294 patients at a tertiary referral center. ANESTHESIOLOGY. 2003;99:259–69
9. Vamvakas EC, Blajchman MA. Transfusion-related mortality: The ongoing risks of allogeneic blood transfusion and the available strategies for their prevention. Blood. 2009;113:3406–17
10. Shakur H, Roberts I, Bautista R, Caballero J, Coats T, Dewan Y, El-Sayed H, Gogichaishvili T, Gupta S, Herrera J, Hunt B, Iribhogbe P, Izurieta M, Khamis H, Komolafe E, Marrero MA, Mejia-Mantilla J, Miranda J, Morales C, Olaomi O, Olldashi F, Perel P, Peto R, Ramana PV, Ravi RR, Yutthakasemsunt SCRASH-2 Trial Collaborators. . Effects of tranexamic acid on death, vascular occlusive events, and blood transfusion in trauma patients with significant haemorrhage (CRASH-2): A randomized, placebo-controlled trial Lancet. 2010;376:23–32
11. Ker K, Edwards P, Perel P, Shakur H, Roberts I. Effect of tranexamic acid on surgical bleeding: Systematic review and cumulative meta-analysis. BMJ. 2012;344:e3054
12. Vacanti CJ, VanHouten RJ, Hill RC. A statistical analysis of the relationship of physical status to postoperative mortality in 68,388 cases. Anesth Analg. 1970;49:564–6
13. Hooper GJ, Rothwell AG, Hooper NM, Frampton C. The relationship between the American Society Of Anesthesiologists physical rating and outcome following total hip and knee arthroplasty: An analysis of the New Zealand Joint Registry. J Bone Joint Surg Am. 2012;94:1065–70
14. Wolters U, Wolf T, Stützer H, Schröder T. ASA classification and perioperative variables as predictors of postoperative outcome. Br J Anaesth. 1996;77:217–22
15. Davenport DL, Bowe EA, Henderson WG, Khuri SF, Mentzer RM Jr. National Surgical Quality Improvement Program (NSQIP) risk factors can be used to validate American Society of Anesthesiologists Physical Status Classification (ASA PS) levels. Ann Surg. 2006;243:636–41 discussion 641–4
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