Preoperative Laboratory Studies for Pediatric Cardiac Surgery Patients: A Multi-Institutional Perspective

While currently standard care in many pediatric institutions, routine collection of laboratory studies during the preoperative visit before cardiac surgery for patients presenting from home is an antiquated practice. Routine laboratory testing has been questioned in healthy outpatient adults1,2 and children3 undergoing minimal risk procedures, and some evidence suggests eliminating routine preoperative laboratory studies in this special cohort of patients.4 We conducted a multi-institutional survey examining current practices at selected pediatric cardiac centers in the United States and Canada and found that, while routine blood work in pediatric patients presenting from home for cardiac surgery is controversial, it does not change patient management. Anesthesiologists are well poised to lead a multidisciplinary reconsideration and change of this current practice. CURRENT PRACTICE Evidence to date suggests that routine laboratory studies do not alter surgical timing or patient management in pediatric cardiac surgical patients presenting from home even in medically complex scenarios. A retrospective review of routine tests obtained for 1106 pediatric cardiac surgical cases demonstrated that 82% of patients had ≥1 “abnormal” value; however, only 0.5% of cases were cancelled due to the abnormality.4 Further, the authors concluded that the hospital would have to order 184 laboratory tests, costing >$379,000, to capture one value that would result in cancellation of surgery.4 A retrospective study of 477 pediatric neurosurgical patients undergoing elective procedures demonstrated abnormal values in complete blood count, electrolytes, and coagulation studies at rates of approximately 40%, 24%, and 25%, respectively; however, only 3 patients had a change in management.5 Medical history alone would have predicted the abnormality in 2 of these 3 patients. Routine preoperative laboratory testing is not without cost to the patient, hospital, and health care system. The charge to the patient for any given test varies by institution and insurance coverage but is a monetary amount that must be paid. The blood drawing process is often an anxiety-provoking event for children and their caregivers.5 Further, children with poor IV access may require several attempts to obtain the necessary blood especially if multiple laboratory studies are ordered. These attempts may yield insufficient quantities of blood for laboratory testing and also reduce potential sites for IV access if the surgery is in the coming days. EXAMINING CURRENT PRACTICE AND NECESSITY The above studies, recognition of potential economic and emotional waste, and movement toward value-based health care led us to examine our practices of routine preoperative laboratory studies in children presenting for elective cardiac surgery. The Hemostasis Interest Group, a collaborative of pediatric cardiac anesthesiologists within the Congenital Cardiac Anesthesia Society, conducted a survey of routine preoperative laboratory practices at selected hospitals across United States and Canada. Surveys were sent to all members of the Hemostasis Interest Group which, at that time, included 15 institutions. Twelve institutions participated in the survey, which addressed the following questions: What routine preoperative laboratory studies are obtained in outpatient pediatric patients (<18 years old) presenting for elective cardiac surgery? Of the routine preoperative laboratory studies obtained, which do the pediatric cardiac anesthesiologists deem necessary? We followed this initial survey with a 6-month “vigilance period” from April 1, 2017 to September 30, 2017, when we reported the following: Any preoperative laboratory value that altered management or resulted in case cancellation or rescheduling. Any occasion during which any member of the team felt that they lacked a laboratory value that would have altered management had it been available. Table.: Results From Initial Preoperative Laboratory Studies Survey Detailing Current Practice From April 2017 to September 2017 From 12 Hemostasis Interest Group InstitutionsResults of our initial survey are reported in the Table. Eleven of the 12 institutions surveyed routinely obtained preoperative laboratory studies at baseline, often including a complete blood count, type and screen, coagulation studies, and a metabolic panel without or with liver function tests (basic or comprehensive, respectively). However, 83% (10 of 12) of the institutions deemed only type and screen and complete blood count necessary before surgery. Importantly, no institution reported an instance of management change or case cancellation related to the presence or absence of a specific preoperative laboratory value; it is possible that not all institutions accurately recorded this information. CHANGES IN CURRENT PRACTICE In April 2018, 1 year after the initial survey, we conducted a follow-up survey to determine changes to institutional preoperative laboratory testing for elective pediatric cardiac surgical patients. Most pediatric cardiac anesthesiologists who participated in our initial survey agreed that they could reduce or eliminate preoperative laboratory studies, but no institution actually made practice changes. Despite evidence suggesting that our current paradigm of routine laboratory testing should be amended, along with self-reported acknowledgement that it does not alter management in the vast majority of cases, many of us continue our practice of preoperative blood draws. Barriers to change include perceived necessity of laboratory studies by cardiologists and cardiac surgeons, fear that information may be missed if a laboratory study is omitted (and the potential medical-legal ramifications of such an omission), and the absence of anesthesiologists in the laboratory ordering process. Moving forward, the Hemostasis Interest Group members are committed to shifting practices; some institutions have started multidisciplinary working groups to further this goal. VALUE-BASED HEALTH CARE The Hemostasis Interest Group participants in the survey support the abolition of “routine” preoperative laboratory studies for elective pediatric cardiac surgical patients, including those with systemic disease. We cite the importance of value-based health care6 as well as the growing evidence that preoperative studies do not change management. This does not mean that patients will not get laboratory studies preoperatively if indicated by history and physical or that institution-specific guidelines for pregnancy testing should be ignored. Rather, the goal is a disease- and patient-centered approach that accounts for individual needs. Several members of the Hemostasis Interest Group raised concerns regarding the elimination of a preoperative type and screen. For many institutions, relying on a day-of-surgery type and screen is a violation of established safe transfusion practice and would not be supported. For other groups, the day-of-service type and screen would be possible if cross-matched blood was available in a timely fashion. A UNIQUE STRATEGY Duke University Medical Center has reconsidered the validity of routine preoperative laboratory testing, eliminating all preoperative studies in elective pediatric cardiac surgical patients, including the type and screen. The current institutional approach is to obtain any laboratory values necessary postinduction, either on arterial blood gas (hemoglobin, potassium) or via stat collection (antithrombin) before cardiopulmonary bypass. Relying on a day-of-service type and screen is accompanied by a practice of having type O negative blood in the room at the time of surgical incision. While a discussion of the merits and consequences of using emergency release blood is beyond the scope of this article, it is possible to ensure blood availability at surgical incision without preoperative type and screen with creativity and significant cooperation between multiple departments. This collaborative effort has allowed Duke to reduce costs while maintaining patient safety. CHANGING THE PARADIGM Even more important than whether testing will change management is whether or not preoperative tests predict postoperative outcomes. For example, Jones et al7 demonstrated increased in-hospital postoperative mortality, hospital length of stay, postoperative sepsis, and requirement for postoperative mechanical circulatory support in patients with lymphopenia, thrombocytopenia, and/or neutrophilia before surgery. However, the authors did not differentiate between inpatients and outpatients, making it difficult to draw conclusions about patients who are presenting from home for cardiac surgery. We acknowledge that correlation between preoperative laboratory values and postoperative outcomes is an understudied area of perioperative pediatric medicine; further research may elucidate which laboratory studies and patient populations need special attention. While we look to the future, we, the Hemostasis Interest Group, argue that routine laboratory testing is not necessary for pediatric patients with systemic disease that is well managed at home who present for elective cardiac surgery. With respect to the preoperative type and screen, anesthesiologists should take the lead in determining the true necessity of long-held institutional practices. Because anesthesiologists continue to lead the Perioperative Surgical Home, we must lead the multidisciplinary effort to ensure that our practices are evidence-based, value-based, and result in improved patient outcomes. DISCLOSURES Name: Stephanie E. Jones, MD. Contribution: This author helped collect institutional data and write the manuscript. Name: Edmund H. Jooste, MBChB. Contribution: This author helped edit the manuscript. Name: Erin A. Gottlieb, MD. Contribution: This author helped collect institutional data and edit the manuscript, Name: Jamie Schwartz, MD. Contribution: This author helped collect institutional data and edit the manuscript. Name: Dheeraj Goswami, MD. Contribution: This author helped collect institutional data and edit the manuscript. Name: Nischal K. Gautam, MBBS. Contribution: This author helped collect institutional data and edit the manuscript, Name: Claudia Benkwitz, MD, PhD. Contribution: This author helped collect institutional data and edit the manuscript, Name: Laura A. Downey, MD. Contribution: This author helped collect institutional data and edit the manuscript. Name: Nina A. Guzzetta, MD. Contribution: This author helped collect institutional data and edit the manuscript. Name: Luis Zabala, MD. Contribution: This author helped collect institutional data and edit the manuscript. Name: Gregory J. Latham, MD. Contribution: This author helped collect institutional data and edit the manuscript. Name: David Faraoni, MD, PhD. Contribution: This author helped collect institutional data and edit the manuscript. Name: Manchula Navaratnam, MD. Contribution: This author helped collect institutional data and edit the manuscript. Name: Lisa Wise-Faberowski, MD, MSCE. Contribution: This author helped collect institutional data and edit the manuscript. Name: Matthew McDaniel, MD. Contribution: This author helped collect institutional data and edit the manuscript. Name: Ellen Spurrier, MD. Contribution: This author helped collect institutional data and edit the manuscript. Name: Kelly A. Machovec, MD, MPH. Contribution: This author helped collect institutional data, write the manuscript, and supervise the direction of the project This manuscript was handled by: James A. DiNardo, MD, FAAP.