Does my patient have a pulmonary embolism? The Wells vs. PISA 2 rule in orthopedic patients.

The diagnosis of venous thromboembolism is difficult in the postoperative setting because signs such as hypoxemia, leg pain, and swelling are so common. CTPA can also detect subsegmental PE (SSPE), of which the clinical significance has been widely debated. Clinical decision rules (CDR), such as the Wells and PISA 2, have been developed to identify symptomatic patients at low risk for PE who could forgo imaging. We performed this study in order to (1) compare the performance of the Wells and PISA 2 CDR in orthopedic patients; (2) compare CDR scores in patients with subsegmental PE (SSPE) versus larger clots; and (3) identify variables that improve performance of the Wells in orthopedic patients. This retrospective cohort study included all orthopedic surgery patients that underwent computerized tomographic pulmonary angiography at a single institution from 1/1/13 to 12/31/14 and had data to calculate both Wells and PISA 2 scores. CDR sensitivity, specificity and c-statistics were calculated. Multivariable logistic regression was used to identify variables that improved CDR performance. 402 patients were included in the study. The Wells rule (cutoff > 4) had sensitivity 74% and specificity 45%. PISA 2 (cutoff 0.6) had sensitivity 90% and specificity 11%. The Wells performed better than PISA 2: c-statistic 0.60 vs. 0.50; p = 0.007. The mean Wells score was 5.20 ± 1.68 for patients with SSPE and 5.41 ± 1.86 for patients with larger clots. Adding the variables prior smoking and varicose veins improved the performance of the Wells rule (c-statistic 0.66 vs. 0.60, p = 0.008). The Wells rule (cutoff > 4) performs better than PISA 2 in orthopedic patients. Neither can distinguish patients with SSPE from those with larger clots. Although adding past smoking and varicose veins to the Wells improves its performance, this requires validation in other populations.

End Tidal Carbon Dioxide as a Screening Tool for Computed Tomography Angiogram in Postoperative Orthopaedic Patients Suspected of Pulmonary Embolism.

BACKGROUND: Computed tomography pulmonary angiography (CTA) is the gold standard for diagnosing pulmonary embolism (PE) but involves radiation and iodinated contrast exposure. Of orthopedic patients evaluated for PE, a minority have a positive CTA study. Herein, we evaluate end tidal carbon dioxide (ETCO2) as a method to identify patients at low risk for PE and may not require a CTA. We hypothesize that ETCO2 will be useful for predicting the absence of PE in postoperative orthopedic patients. METHODS: In this prospective study, all patients older than 18 years who were admitted for orthopedic surgery and who had a CTA performed for PE were eligible. These patients underwent an ETCO2 measurement. Patients were determined to have PE if they had a positive PE-protocol CT. RESULTS: Between May 2014 and April 2015, 121 patients met the inclusion criteria for the study. Of these patients, 84 had a negative CTA examination, 25 had a positive examination, and 12 had a nondiagnostic examination. We found a statistically significant difference (P = .03) when comparing the average ETCO2 values for the positive and negative CTA groups. An ETCO2 cutoff value of 43 mm Hg was 100% sensitive with a negative predictive value of 100% for absence of PE on CTA. CONCLUSION: This study demonstrates a significant difference in ETCO2 measurements between postoperative orthopedic patients with and without CTA-detected PE. A cutoff value of >43 mm Hg may be useful in excluding patients from undergoing CTA.

Expanding the perioperative lens: Does the end justify the means?

In 1994, Fischer et al. established the preoperative clinic for the perioperative services at Stanford University Medical Center. By lowering the risk of cancellation and reducing morbidity and mortality against the push to move surgeries to an outpatient, basis, they demonstrated a return on investment. In the 2000s, Aronson et al. designed the prehabilitation clinics at Duke University with the notion that the preoperative process should not only ensure that patients were appropriately risk-stratified, but also clinically optimized before surgery. With a trend towards ambulatory procedures due to current reimbursement structures, hospital administrators should be searching for potential avenues to bolster sagging profits. In this narrative review, we argue that the perioperative services needs to extend beyond the hospital into the postoperative period.

Postoperative Tachycardia: Clinically Meaningful or Benign Consequence of Orthopedic Surgery?

OBJECTIVE: To determine the clinical significance of tachycardia in the postoperative period. PATIENTS AND METHODS: Individuals 18 years or older undergoing hip and knee arthroplasty were included in the study. Two data sets were collected from different time periods: development data set from January 1, 2011, through December 31, 2011, and validation data set from December 1, 2012, through September 1, 2014. We used the development data set to identify the optimal definition of tachycardia with the strongest association with the vascular composite outcome (pulmonary embolism and myocardial necrosis and infarction). The predictive value of this definition was assessed in the validation data set for each outcome of interest, pulmonary embolism, myocardial necrosis and infarction, and infection using multiple logistic regression to control for known risk factors. RESULTS: In 1755 patients in the development data set, a maximum heart rate (HR) greater than 110 beats/min was found to be the best cutoff as a correlate of the composite vascular outcome. Of the 4621 patients who underwent arthroplasty in the validation data set, 40 (0.9%) had pulmonary embolism. The maximum HR greater than 110 beats/min had an odds ratio (OR) of 9.39 (95% CI, 4.67-18.87; sensitivity, 72.5%; specificity, 78.0%; positive predictive value, 2.8%; negative predictive value, 99.7%) for pulmonary embolism. Ninety-seven patients (2.1%) had myocardial necrosis (elevated troponin). The maximum HR greater than 110 beats/min had an OR of 4.71 (95% CI, 3.06-7.24; sensitivity, 47.4%; specificity, 78.1%; positive predictive value, 4.4%; negative predictive value, 98.6%) for this outcome. Thirteen (.3%) patients had myocardial infarction according to our predetermined definition, and the maximum HR greater than 110 beats/min had an OR of 1.72 (95% CI, 0.47-6.27). CONCLUSION: Postoperative tachycardia within the first 4 days of surgery should not be dismissed as a postoperative variation in HR, but may precede clinically significant adverse outcomes.

Use of Preoperative Testing and Physicians' Response to Professional Society Guidance.

IMPORTANCE: The value of routine preoperative testing before most surgical procedures is widely considered to be low. To improve the quality of preoperative care and reduce waste, 2 professional societies released guidance on use of routine preoperative testing in 2002, but researchers and policymakers remain concerned about the health and cost burden of low-value care in the preoperative setting. OBJECTIVE: To examine the long-term national effect of the 2002 professional guidance from the American College of Cardiology/American Heart Association and the American Society of Anesthesiologists on physicians' use of routine preoperative testing. DESIGN, SETTING, AND PARTICIPANTS: Retrospective analysis of nationally representative data from the National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey to examine adults in the United States who were evaluated during preoperative visits from January 1, 1997, through December 31, 2010. A quasiexperimental, difference-in-difference (DID) approach evaluated whether the publication of professional guidance in 2002 was associated with changes in preoperative testing patterns, adjusting for temporal trends in routine testing, as captured by testing patterns in general medical examinations. MAIN OUTCOMES AND MEASURES: Physician orders for outpatient plain radiography, hematocrit, urinalysis, electrocardiogram, and cardiac stress testing. RESULTS: During the 14-year period, the average annual number of preoperative visits in the United States increased from 6.8 million in 1997-1999 to 9.8 million in 2002-2004 and 14.3 million in 2008-2010. After accounting for temporal trends in routine testing, we found no statistically significant overall changes in the use of plain radiography (11.3% in 1997-2002 to 9.9% in 2003-2010; DID, -1.0 per 100 visits; 95% CI, -4.1 to 2.2), hematocrit (9.4% in 1997-2002 to 4.1% in 2003-2010; DID, 1.2 per 100 visits; 95% CI, -2.2 to 4.7), urinalysis (12.2% in 1997-2002 to 8.9% in 2003-2010; DID, 2.7 per 100 visits; 95% CI, -1.7 to 7.1), or cardiac stress testing (1.0% in 1997-2002 to 2.0% in 2003-2010; DID, 0.7 per 100 visits; 95% CI, -0.1 to 1.5) after the publication of professional guidance. However, the rate of electrocardiogram testing fell (19.4% in 1997-2002 to 14.3% in 2003-2010; DID, -6.7 per 100 visits; 95% CI, -10.6 to -2.7) in the period after the publication of guidance. CONCLUSIONS AND RELEVANCE: The release of the 2002 guidance on routine preoperative testing was associated with a reduced incidence of routine electrocardiogram testing but not of plain radiography, hematocrit, urinalysis, or cardiac stress testing. Because routine preoperative testing is generally considered to provide low incremental value, more concerted efforts to understand physician behavior and remove barriers to guideline adherence may improve health care quality and reduce costs.