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Evidence Based Medicine and Level 1 Outcomes Research in Pediatric Surgery. George W. Holcomb, III, M.D., MBA Children’s Mercy Hospital Kansas City, Missouri Center for Prospective Clinical Trials www.cmhclinicaltrials.com. The Right People. Evidence Based Medicine.
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Evidence Based Medicine and Level 1 Outcomes Research in Pediatric Surgery George W. Holcomb, III, M.D., MBA Children’s Mercy Hospital Kansas City, Missouri Center for Prospective Clinical Trials www.cmhclinicaltrials.com
Evidence Based Medicine • Integration of best research evidence with clinical expertise and patient values • Treating patients based on data, not “feeling” (gestalt), or one’s own experience
Levels of EvidenceQuestion A clinical surgeon publishes a retrospective review of 350 patients over 20 years undergoing an endorectal pull-through (Soave procedure) for Hirschsprung’s Disease. This is felt to be a seminal paper on this disease in infants and children. What is the level of evidence for this paper? Level 1 (A) Level 2 (B) Level 3 (C) Level 4 (D) Level 5 (E)
Levels Of Evidence 5– Expert opinion, or applied principles from physiology, basic science, or other conditions 4 – Case series or poor quality case control and cohort studies 3 – Case control studies 2 – Review of case control or cohort studies with agreement or poor quality randomized trial 1 – Prospective, randomized controlled trials
Levels of Evidence • Expert opinion, or applied principles from physiology, basic science, or other conditions Example: • Leave patient intubated and paralyzed for 3-5 days following an esophageal resection to take tension off esophageal anastomosis No data – no study to show intubated/paralyzed patient has less esophageal tension • Transverse incision is used for abdominal exploration in baby b/c better exposure No data to support this practice
Levels of Evidence • Case series or poor quality case control and cohort studies Example: • Paper reviewing results from one approach to a disease Large retrospective review of Soave operation for Hirschsprung’s Disease
Levels of Evidence • Case control studies Example: • Paper showing different management strategies/operative technique for one disease process Single center (or multicenter) retrospective review of Duhamel vs Soave operation for Hirschsprung’s Disease
Levels of Evidence • Review of case control or cohort (followed “long-term”) studies with agreement or a poorly performed prospective randomized trial Example: • Review of two or three large series describing one management strategy (Soave procedure) compared to two or three large series describing another management strategy (Duhamel procedure)
Levels of Evidence • Prospective randomized trials
Flawed Prospective Studies Are Usually Better Than Retrospective Data Collections
p - Value • Commonly accepted p-value is 0.05 • 5/100 (1/20) chance that if a difference is found b/w variables, there really is no difference b/w the variables • If p=0.01 there is a 1/100 chance that if a difference is found b/w variables, there really is no difference • P=0.07 7/100 – still pretty significant, but readers will think there really is no significance b/c >0.05 (depends on what variable one is looking at)
How To Set Up a Study • Alpha –Usually 0.05 is used; establishes level of significance of study • Value is used to determine # of patients needed • Retrospective fundoplication review: 12% vs 5% • 360 patients needed to show a significant difference • If α was 0.1, need fewer patients • If α was 0.01, need more patients (because significance is greater) • Set the α low to avoid a Type I error
How To Set Up a Study • Power – commonly accepted is 0.8 • 20% chance that the study will fail to detect a difference when there really is one or • 80% chance that the study will detect a difference when one does exist • Underpowering a study risks a Type II error
Children’s Mercy Hospital Focus on common conditions which are “controversial”: • Pyloric stenosis • Appendicitis • Pectus excavatum • Fundoplication for reflux • Empyema • Non-palpable intra-abdominal testis
Remember • There is a lot more to an MIS operation than just technique • Postoperative care is also important and open for study (antibiotics?, pain management?, etc.)
Landscape of Pediatric Surgery • Young field, most practicing surgeons are 2-3 generations removed from the founders of the field • Very few training centers, the opinions of a few affect the masses • Wide variety of rare cases make acquisition of objective treatment data difficult
Open vs Lap Pyloromyotomy • Lap vs Open – 2003 - controversial around the world and in our hospital • Different feeding regimens used in our hospital (2 hours, 4 hours, 6 hours) • Different postoperative pain management strategies utilized • Differences between staff made it difficult for residents, NPs, floor nurses • Benefits: single protocol for feeding, pain management, discharge used in study still used currently (6 years later) • No level 1 data
OR time (mins) 19:28 +/- 0.60 19:34 +/- 0.78 Emesis (#) 2.61 +/- 0.27 1.84 +/- 0.23 Full Feeds (hrs) 21:01 +/- 2.16 19:30 +/- 1.46 LOS (hrs) 33:10 +/- 1.63 29:38 +/- 1.69 Tylenol (doses) 2.23 +/- 0.18 1.59 +/- 0.16 ResultsOutcomes OPEN (n = 100) LAP (n = 100) P Value (Mean +/- S.E.) (Mean +/- S.E.) 0.93 0.05 0.43 0.12 0.01 Ann Surg 244:363-370, 2006
Conclusions • Operative approach for pyloromyotomy has no significant influence on operating time or length of recovery • Laparoscopic pyloromyotomy results in significantly less post-operative discomfort • Fewer episodes of emesis and doses of Tylenol • Laparoscopic pyloromyotomy results in obvious cosmetic benefits ASA, 2006
Treatment Of Empyema • Fibrinolysis had been shown to be better than chest tube drainage alone • Primary thoracoscopic debridement had been shown to better than tube drainage alone in several retrospective studies • At the initiation of this study, there were no comparative data between primary thoracoscopic debridement and fibrinolysis as initial treatment for empyema in children
Sample Size • Using our own institution’s retrospective data on length of hospitalization after intervention between thoracoscopic debridement and fibrinolysis with an alpha 0.05 and power of 0.8 • Sample size of 36 with 18 in each arm
Empyema Study ProtocolFibrinolysis • 12 Fr tube placed by IR or surgery in procedure room • 4mg tPA in 40ml NS given into tube on insertion and each day for 3 doses Thoracoscopy • Thoracoscopic debridement with chest tube left behind on – 20 cm H20 suction J Pediatr Surg 44:106-111, 2008
Empyema Study ProtocolPrimary Outcome Measure • Length of hospitalization after intervention (tPA or thoracoscopic debridement) until discharge criteria met (chest tube removed, afebrile & oral analgesics) J Pediatr Surg 44:106-111, 2008
Empyema Study ProtocolSecondary Outcome Measure • Days of Tmax > 38CDays of tube drainage • Doses of analgesia • Days of oxygen requirement • Hospital charges after intervention • Procedure charges J Pediatr Surg 44:106-111, 2008
Study Results Patient Variables at Consultation VATS tPA P Value Age (Years) 4.8 5.2 0.77 Weight (kg) 24.6 20.7 0.52 WBC 20.8 19.7 0.71 O2 support (L/min) 0.81 0.79 0.96 Days of Symptoms 9.0 10.6 0.32 ER/PCP visits 2.9 2.7 0.69 J Pediatr Surg 44:106-111, 2008
LOS (Days) 6.89 6.83 0.96 O2 tx (Days) 2.25 2.33 0.89 PO Fever (Days) 3.1 3.8 0.46 Analgesic doses 22.3 21.4 0.90 Patient Charges $11,660 $7,575 0.01 Study Results Outcomes VATS tPA P Value 16.6% failure rate for fibrinolysis J PediatrSurg 44:106-111, 2008
London Prospective Trial VATS v Fibrinolysis w/Urokinase • No difference in LOS (6 v 6 days) • No difference in 6 month CXR • VATS more expensive ($11.3K v $9.1K) • 16 % failure rate for fibrinolysis Am J Respir Crit Care Med 174:221-227, 2006
CONCLUSIONS • There appears to be no therapeutic or recovery advantages to thoracoscopic debridement compared to fibrinolysis as the primary treatment for empyema • Thoracoscopy results in significantly higher patient charges J PediatrSurg 44:106-111, 2008
PRCTs Now Enrolling • Burn study – SSD vs collagenase (100/150) – Stopped early at interim analysis • One stage vs 2 stage laparoscopic orchiopexy for intra-abdominal testis (28/30) • Standardized feeding protocol vs ad lib feedings following laparoscopic pyloromyotomy (100/150) • Esophago-crural sutures vs no sutures at laparoscopic fundoplication (both groups receive minimal esophageal dissection), APSA 2010 • Irrigation/suction vs suction alone in patients with perforated appendicitis American Surgical 2012? • Use of US vs landmark guided CVL placement (with Stanford) (40/80) • IR drainage of appendiceal abscess with vs w/o instillation of fibrinolytic agent (tPA) (39/62) • SSULS cholecystectomy vs 4 port lap cholecystectomy, APSA 2012? • SSULS splenectomy vs 4 port lap splenectomy (6/30)
Summary • Evidence based decision making will continue to have a stronger presence in medical training • Patient management will continue to become more influenced by evidence over opinion • Hurdles to performing prospective trials in surgery and medicine are mostly surmountable
QUESTIONS www.cmhclinicaltrials.com