RESCUE ECHOCARDIOGRAPHIC FINDINGS ARE DIFFERENT BASED ON PATIENT SETTING

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1 RESCUE ECHOCARDIOGRAPHIC FINDINGS ARE DIFFERENT BASED ON PATIENT SETTING Item Type Thesis Authors Vanhoy,Steven Publisher The University of Arizona. Rights Copyright is held by the author. Digital access to this material is made possible by the College of Medicine - Phoenix, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 10/07/ :00:07 Link to Item

2 RESCUE ECHOCARDIOGRAPHIC FINDINGS ARE DIFFERENT BASED ON PATIENT SETTING A Thesis submitted to the University of Arizona College of Medicine Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine Steven Vanhoy Class of 2015 Mentor: Dr. Harriet Hopf

3 Acknowledgements: The author would like to acknowledge and give appreciation to the Foundation for Anesthesia Education and Research (FAER) for providing funds to make this research fellowship possible. This project would not have been possible without Dr. Harriet Hopf; whose dedicated mentorship throughout my four years of medical school has helped shaped me into the physician I wanted to become. Further appreciation is showed to the echocardiography team at the University of Utah Department of Anesthesia, specifically Dr. Matt Griffee, Dr. Tim Holmberg, and Dr. Ben Gmelch for supporting me through this project.

4 Abstract Objective: To compare findings of emergency echocardiography (rescue echo) in the intraoperative period to findings of rescue echo in the ICU setting. Design: We queried a database of perioperative echo for all rescue echo studies done over a two year period. We compared the frequency of left ventricular (LV) and right ventricular (RV) systolic dysfunction, LV diastolic dysfunction, LV segmental wall motion abnormalities, and hypovolemia of the intraoperative and ICU studies. Results: LV and RV systolic dysfunction were more prevalent in ICU rescue echo studies compared to intra op rescue studies (22% vs. 10%, and 34% vs. 13%, respectively, p<0.05 for each). LV diastolic dysfunction was more prevalent in ICU rescue echo studies compared to intra op rescue studies (60% vs. 48%, p<0.05). Segmental wall motion abnormalities (SWMA) were more prevalent in the ICU compared to intra op setting (38% vs. 19%, p<0.05). Conclusion: In an observational study of real world rescue echo, the incidence of LV and RV systolic dysfunction, LV diastolic dysfunction, and LV SWMA were all more common in the ICU compared to the intra op studies. This could reflect the differences in patient population, differences in reasons clinicians perform rescue echo in the OR and in the ICU, or the hemodynamic effects of anesthesia.

5 Contents Introduction... 1 Methods... 2 Statistical Methods... 5 Results... 5 Discussion Future Directions Conclusion References... 13

6 List of Figures and Tables Tables Table 1 Classification of echocardiographic findings based on ACC guidelines (Page 4) Figures Figure 1 Echocardiographic assessment of left ventricular systolic function based on patient setting (Page 6) Figure 2 Echocardiographic assessment of right ventricular systolic function based on patient setting (Page 7) Figure 3 Echocardiographic assessment of left ventricular dyastolic function based on patient setting (Page 8) Figure 4 Echocardiographic assessment of segmental wall motion abnormalities based on patient setting (Page 9)

7 Introduction Perioperative echocardiography has long been established as an important diagnostic modality in cardiac surgery. It is also used to guide hemodynamic management of non cardiac surgical patients in the operating room (OR). For example, when large volume shifts are expected or the patient shows unexplained hemodynamic instability 1. Recently echocardiography has also been shown to valuable perioperatively in unstable non cardiac surgery patients. Thus, echocardiography has a wide applicability as a perioperative diagnostic tool 2. Post operatively, transthoracic and transesophageal echocardiography (TTE and TEE) have shown greater utility in guiding diagnostic and therapeutic decisions than both clinical diagnosis and invasive hemodynamic monitoring 5,6,7,12. Prior studies have demonstrated the value of urgent echocardiography ( rescue echocardiography ) in patients with unexplained hemodynamic instability. Rescue echocardiography has been advocated by two sets of professional guidelines; published by the American College of Cardiology/American Heart Association (ACC/AHA) and the American Society of Anesthesiology/Society of Cardiovascular Anesthesiologists (ASA/SCA). There are distinct differences in demographics, disease severity, pharmacologic milieu, and the incidence of certain clinical conditions between patients with hemodynamic instability in the operating room, and in patients with hemodynamic instability in the surgical intensive care unit (SICU). However, the incidence of certain echocardiographic diagnoses in hemodynamically unstable patients in each of these clinical settings has not yet been described in a large cohort. We hypothesized that the predominant findings of rescue echocardiography in the OR and ICU are different. The primary goal of this study was to describe the incidence of findings in the intraoperative and intensive care setting. The secondary goal was to determine how often rescue echocardiography leads to a change in clinical strategy. 1

8 Methods The Department of Anesthesiology at the University of Utah provides a consultative echocardiography service 24 hours per day, 7 days per week. The service is staffed exclusively by a team of 8 12, level 3 trained echocardiographers. Consultation requests for urgent echocardiography originate from the provider in the operating room, the post anesthesia care unit, the surgical ICU, and the neurocritical care unit. The University of Utah is a tertiary care center academic hospital with a Level I trauma accreditation. IRB approval was obtained to audit patient charts, echocardiographic images, and echocardiography reports in the imaging database. All echocardiography reports between February 2010 and June 2012 were categorized as rescue vs. non rescue studies. Out of 1679 echo studies performed in the 28 month period, 423 rescue echo studies were identified. A rescue study was defined as a non routine echocardiogram requested to assess hemodynamic instability. Requests for rescue echocardiographic exams were made by anesthesiologists, surgeons, and intensivists working in the OR and SICU. All exams were conducted and read by a member of the consultative echo team. A formal report was prepared for all TEE and TTE exams and was entered into the electronic medical record. Transesophageal echocardiograms at the University of Utah include a standardized 13 clip basic exam, adapted from the 20 clip comprehensive TEE exam 13. In addition, diastolic function, if deemed indicated by the echocardiographer, is evaluated according to current American Society of Echocardiography recommendations. Standard perioperative transthoracic echocardiograms consist of at least a 10 clip basic exam, including diastology if indicated. Studies were performed with either a Philips CX 50 machine (TTE), Philips IE33 machine (TEE), or a Siemens Sequoia. Rescue studies were audited and diagnoses were tabulated based upon the most recently published standards of the American Society of Echocardiography (ASE) for quantification of left ventricular and right ventricular systolic function, left ventricular diastolic function, segmental wall motion abnormalities (SWMA), hypovolemia, pericardial tamponade, severe valvular abnormalities, and dynamic left ventricular outflow tract (LVOT) obstruction. 2

9 The categorization of RV systolic function deviated from the ASE guidelines because clinically moderate and severe dysfunction results in relatively similar intervention, and thus they were grouped into one category. 3

10 Table 1: criteria for classification of echo diagnoses: Table 1. Classification of Findings Used Diagnosis LV Systolic Function LV Diastolic Function SWMA RV Systolic Function Pericardial Effusion Category Severely decreased (EF <30%) Moderately decreased (EF 44% 30%) Normal (EF 70% 45%) Hyperdynamic (EF >70%) Normal Impaired relaxation Pseudonormal Restrictive Not Present Present Moderately or severely decreased Mildy decreased Normal Hyperdynamic None Effusion w/o tamponade Pericardial tamponade 4

11 Statistical Methods A Kruskal Wallis test and ordered logistic regression were used to compare incidental differences between the group of rescue echocardiograms performed in the OR and the group performed in the ICU with the R statistical package. Results 1679 echocardiograms were performed during the 28 month study period nonrescue studies (e.g., routine studies performed during open heart surgery) and 12 pre operative studies were excluded, leaving 423 studies for analysis. The incidences of pericardial tamponade, hypovolemia, dynamic LVOT obstruction, and hemodynamically significant valvular abnormalities were so infrequent that we were unable to demonstrate a statistically significant difference in the frequency of these findings between intraoperative and postoperative studies. 5

12 Figure 1: LV systolic function was classified as severely decreased, moderately decreased, normal, and hyperdynamic. Severe and moderate dysfunction were more prevalent in ICU rescue studies. Normal and hyperdynamic function were more prevalent in OR rescue studies. The overall distribution of LV systolic function categories was significantly different comparing intra op and ICU studies (p<0.05, OR 2.4, 95% CI ). 6

13 Figure 2: RV systolic function diagnostic categories were moderate/severely decreased, mildly decreased, normal, and hyperdynamic. The prevalence of mild and moderate/severe dysfunction was higher in ICU rescue studies compared to OR studies. Normal and hyperdynamic RV function was more common in OR studies. The overall distribution of RV systolic function categories (figure 2) was significantly different in the OR compared to the ICU rescue echocardiograms (p<0.05, OR 5.3, 95% CI ). 7

14 Figure 3: LV diastolic function was categorized as normal, impaired relaxation, pseudonormal, or restrictive. Diastolic dysfunction was more prevalent in the ICU studies compared to the OR studies (figure 3, p<0.05, OR 1.8, 95% CI ). 8

15 Figure 4: Segmental wall motion abnormalities of the LV were classified as present vs. absent. The prevalence of SWMA was higher in the ICU studies compared to the intraoperative studies (figure 4, p<0.05, OR 1.2, 95% CI ). 9

16 Discussion Echocardiography has proven to be a valuable diagnostic tool in the operating room as well as the intensive care unit. We present the findings of a unique, 24/7 perioperative echocardiography service, reviewing rescue echocardiograms for both operative and nonoperative patients during a 28 month period. With an increasing number of anesthesiologists trained in critical care and managing patients in the intensive care unit, the scope of our specialty is expanding further into the post operative period as well as to non operative patients. Our observational review demonstrated a significant difference in the incidence of LV systolic and diastolic dysfunction between intraoperative and ICU patients, with ICU patients showing a greater degree of both systolic and diastolic dysfunction. The incidence of segmental wall motion abnormalities, as well as RV dysfunction, was also higher in the ICU compared to the operating room. The bottom line to this retrospective review is that in both settings there was no predominant diagnostic finding with rescue echocardiography. This makes its use even more important in the perioperative setting. Because we did not find a predominant cause of hemodynamic instability, there can be no assumption of the diagnosis based on the common things are common rule. This finding is paralleled in other published studies that have looked at hemodynamic instability in the OR and ICU settings 1,2. Of note, no diagnosis in either setting accounted for more than 40% of the cause for hemodynamic instability. When the most common diagnoses found are hypovolemia and ventricular dysfunction, it is important to know which is being treated to prevent undo harm to the patient. This observation is consistent with previous studies and supports the fact that rescue echocardiography is a necessary part of perioperative care 10,12. The differences in incidence of primary findings in the ICU vs the OR could be due to differences in disease severity in patients who are referred for rescue echo in the OR as compared to the ICU. A second explanation could be that a significant number of our rescue echoes performed in the ICU involved non operative patients. These non operative patients could self select for a group that had a higher incidence of cardiac dysfunction because most intraoperative patients have to be hemodynamically optimized before surgery. Although the 10

17 measurement of disease severity scores is beyond the scope of this study, it is possible that the ICU patients had a higher baseline disease severity at the time of exam than intraoperative patients. A third explanation is that our findings could reflect a difference in the criteria, or hemodynamic severity threshold, for echo consultation in the OR vs. the ICU. In the operating room the patient is already sedated and intubated, thus making it easier to make the decision to perform TEE. In the ICU if the patient is awake, but unstable, more consideration is taken before a TEE is performed. This, to some degree, may represent an unavoidable selection bias inherently present in a retrospective observational study. Regardless of the reason for the findings, our study represents a real world scenario in which the probability of certain cardiovascular conditions was higher in the ICU population. Awareness of the difference in pre test probability of these cardiovascular conditions in ICU vs. intraoperative patients is a crucial element to guide clinical decision making, as well as to guide cost conscious and risk conscious utilization of diagnostic modalities such as pulmonary artery catheterization and transesophageal echocardiography. Because of the known hemodynamic changes associated with anesthesia, including venous and arterial dilation leading to predictable decreases in preload and afterload, we expected to find a higher prevalence of relative hypovolemia in OR studies compared to ICU studies. Unexpectedly, we found that volume status was not frequently documented in any of the echo reports. This has led to a quality improvement measure to document volume status more often, as this category was not included in the template for the echocardiography reports. Volume assessment, therefore, may have been left out of the written form even when it was verbally communicated to the requesting team. 11

18 Future Directions A number of small cohorts that have explored rescue echocardiography and its importance to perioperative medicine state that documented findings frequently led to change in management. We were unable to determine changes in management from our database. In the future, the echocardiography team at the University of Utah, plans to further explore how often using rescue echo changed management in our patients. The most important question is not where specific diagnoses are more common, but rather, how often does using this relatively invasive diagnostic modality actually changes patient care. If rescue echocardiography often changes patient management then training in the technique should become required for future anesthesiologists. Conclusion In a real world observational study of rescue echo findings, there was a higher frequency of LV and RV systolic dysfunction, LV diastolic dysfunction, and LV SWMA in ICU compared to OR studies. The distribution of findings was significantly different in the intraoperative vs. ICU settings. This may reflect an increased disease severity in ICU patients, or different hemodynamic and pharmacologic profiles in these patients as compared to intraoperative patients. The structured audits of the echo database lead to a quality improvement decision to include volume status in the echocardiogram reports more consistently. 12

19 References 1. Hofer CK, Zollinger A, Rak M, et al: Therapeutic impact of intra operative transesophageal echocardiography during noncardiac surgery. Anesth Analg : Shillcutt SK, Markin NW, Montzingo CR, et al: Use of Rapid Rescue Perioperative Echocardiography to improve outcomes after hemodynamic instability in noncardiac surgical patients. J Cardiothorac Vasc Anesth 26:362 70, Wheeler AP, Bernard GR, Thompson BT, et al: Pulmonary artery versus central venous catheter to guide treatment of acute lung injury. N Engl j Med 2006; 354: Schwann NM, Hillel Z, Hoeft A, et al: Lack of effectiveness of the pulmonary artery catheter in cardiac surgery. Anesth Analg 2011 Publish ahead of Print, September Beaulieu Y. Bedside echocardiography in the assessment of the critically ill. Crit Care Med 2007; 35[Suppl.]:S Griffee MJ, Merkel MJ, Wei KS. The role of echocardiography in hemodynamic assessment of septic shock. Crit Care Clin 2010: 26: Vieillard Baron A, Slama M, Cholley B, et al: Echocardiography in the intensive care unit: from evolution to revolution? Intensive Care Medicine 208; 34: Cowie B. Three years experience of focused cardiovascular ultrasound in the perioperative period. Anesthesia 2011; 66: Desouza KA, Desouza NA, Pinto RM, et al: Transthoracic echocardiogram is a useful tool in the hemodynamic assessment of patients with chest trauma. Am J Med Sci 2011; 341(5): Bergenzaun L, Gudmundsson P, Oehlin H, et al: Assessing left ventricular systolic function in shock: evaluation of echocardiographic parameters in intensive care. Critical Care 2011; 15:R200, accessed R Development Core Team (2008). R: A language and environment for statistical computing. R Foundation for Statistical Computing Vienna, Austria. ISBN , URL project.org. 12. Colreavy FB, Donovan K, LeeKY, et al: Transesophgeal echocardiography in critically ill patients. Crit Care Med 30:989 96,

20 13. Shanewise JS, Cheung AT, Aronson S, et al: ASE/SCA guidelines for performing a comprehensive intraoperative multiplane transesophageal echocardiography examination: recommendations of the American Society of Echocardiography Council for Intraoperative Echocardiography and the Society of Cardiovascular Anesthesiologists Task Force for Certification in Perioperative Transesophageal Echocardiography. Anesth Analg Oct;89(4):