Nicholas R. Teman

Two Decades' Experience With Interfacility Transport on Extracorporeal Membrane Oxygenation

BACKGROUND Interfacility transport of patients on extracorporeal membrane oxygenation (ECMO) has been performed in large numbers at only a few programs. Limited data are available on outcomes after ECMO transport to justify expanding or discontinuing these programs. METHODS This was a retrospective review of a 20-year, single-institution experience with interhospital ECMO transport as well as a systematic review of reports of transfers of patients on ECMO. Results of both were compared with historical data from the international registry of the Extracorporeal Life Support Organization (ELSO). RESULTS Between 1990 and 2012, ECMO was used to facilitate transport of 221 patients to our institution, and 135 (62%) survived to discharge. Review of an additional 27 case series describing ECMO transport of 643 patients showed an overall survival of 61%. After stratifying by age and primary indication for ECMO, survival of transported patients was not significantly different compared with all ECMO patients in the ELSO registry, with the exception of pediatric patients treated for respiratory failure (transported patients in this category had higher survival than those in the ELSO registry). CONCLUSIONS Interfacility transport on ECMO is feasible and can be accomplished safely in the critically ill. Survival of transported patients is comparable to age-matched and treatment-matched ECMO patients at large.

Entrustment of General Surgery Residents in the Operating Room: Factors Contributing to Provision of Resident Autonomy

BACKGROUND Several challenges threaten the traditional premise of graduated independence in general surgery training, leading to a lack of readiness in graduating surgeons. The objective of this study was to determine the factors contributing to faculty decisions to grant residents autonomy in the operating room, the barriers to granting this autonomy, and the factors that facilitate entrustment. STUDY DESIGN An anonymous online survey was distributed to 239 attending surgeons at 7 institutions. Questions consisted of open-ended and structured 5-point Likert scale questions. Descriptive statistics were calculated, and a qualitative analysis of free-text responses was performed to identify emergent themes. RESULTS There were 116 attending surgeons who responded to the survey (49%). Factors most important to increasing resident responsibility and autonomy in the operating room were the residents observed clinical skill and the attending surgeons confidence level with the operation. Factors believed to prevent awarding graduated responsibility and autonomy in the operating room included an increased focus on patient outcomes, a desire to increase efficiency and finish operations earlier, and expectations of attending surgeon involvement by the hospital and patients. Among themes discerned in faculty responses to an open-ended question about the greatest challenges in graduate surgical education, 47% of faculty identified work-hour regulations/time restrictions. Fourteen percent pointed to a change to a shift-work mentality and decreased ownership of responsibility for patients by residents; 13% described a lack of resident autonomy due to increased supervision requirements. CONCLUSIONS This study identified several factors that attending surgeons report as significant limitations to transitioning autonomy to surgical residents in the operating room. These issues must be addressed in a direct manner if progressive graduated responsibility to independence is to occur in the next era of graduate surgical training.

Optimal endovascular methods for placement of bicaval dual-lumen cannulae for venovenous extracorporeal membrane oxygenation

Early mobility is associated with improved outcomes in critically ill patients with acute respiratory failure. The Avalon Elite Bicaval Dual-Lumen cannula provides support for extracorporeal membrane oxygenation through a single cannula in the internal jugular position in the neck, avoiding femoral cannulation. This allows the patient to participate in early mobility and strength exercises, facilitating early reconditioning. Placement of the Avalon bicaval cannula poses a potential risk of intracardiac placement and right ventricular rupture as a result of the flexibility of the guidewire. We present our endovascular technique for Avalon bicaval cannula placement with fluoroscopic guidance to prevent inadvertent intracardiac placement.

Preserving operative volume in the setting of the 2011 ACGME duty hour regulations

OBJECTIVES The reported influence of Accreditation Council for Graduate Medical Education resident duty hour limitations on operative case volume has been mixed. Additional restrictions instituted in July 2011 further limited the work hours of postgraduate year 1 (PGY-1) residents, threatening to reduce availability for educational and operative activities. In this study, we evaluate our novel intern call schedule, which we hypothesized would preserve operative experience despite these increased restrictions. DESIGN A retrospective analysis of PGY-1 operative reports was conducted. Operations outside of major case categories were excluded. Operative case volumes in the Section of General Surgery for the same period were analyzed, as were average duty hours for each resident. Comparative statistics were generated using Wilcoxon rank sum tests. SETTING Single-institution study conducted at the University of Michigan, a tertiary-care academic hospital. PARTICIPANTS Overall, 50 categorical general surgery residents from 2005 to present were included. Three residents were subsequently excluded as they were preliminary interns rather than categorical; 2 residents were excluded having completed their intern years at other institutions. RESULTS The median number of major cases done during the PGY-1 for all evaluated residents was 89 (interquartile range [IQR]: 72-101). For interns between the years 2005 and 2011, the median number of major cases was 87 (IQR: 73-101), whereas interns in the 2011 to 2013 academic years performed 91.5 (IQR: 69.5-101.5, p = 0.91). Although case volume varied between intern classes, no significant differences were observed between any 2 individual classes in the study. Analysis of annual case volumes among each PGY revealed a relative increase of 29% (p < 0.001) among PGY-2 residents, and 20% (p = 0.02) by PGY-3 residents. Relative increases among senior residents (8% for both PGY-4 and PGY-5) did not reach statistical significance. CONCLUSIONS Our novel call schedule attempts to minimize prolonged night-float coverage responsibilities for interns in hopes of preserving their operative experience. In spite of increased duty hour restrictions, PGY-1 operative volume has not decreased significantly at our institution. However, in the same time period, PGY-2 and PGY-3 case volume has increased. Our findings highlight the challenges faced by surgical residencies in light of these new restrictions, particularly the 16-hour limit. Additional rigorously designed prospective studies should be conducted to better understand the influence of the most recent Accreditation Council for Graduate Medical Education work hour limitations on the subjective and objective experiences of surgical residents.

“Prophylactic” Tricuspid Repair for Functional Tricuspid Regurgitation

BACKGROUND The optimal management of functional tricuspid regurgitation (FTR) in the setting of mitral valve operations remains controversial. The objective of this study is to compare the outcomes of congestive heart failure patients who underwent a prophylactic tricuspid operation for FTR as a component of their initial mitral valve procedure with those who underwent a redo tricuspid operation at a later date for residual FTR. METHODS Patients with FTR repaired as a redo operation between 2004 and 2012 were identified. These patients were propensity-matched 1:2 with contemporaneous patients with FTR or tricuspid dilatation who underwent tricuspid repair at the same time as mitral valve repair. Demographic information, postoperative complications, and short-term and long-term mortality rates were compared between groups. RESULTS There were 21 patients treated with redo tricuspid valve repair matched with 42 patients treated prophylactically. There were 3 deaths at 30 days in the redo group (14%), compared with zero in the prophylactic group (p=0.03). Overall long-term mortality in the redo group was 29% (6 of 21), with a mean 31 months of follow-up, but was only 14% (6 of 42) in the prophylactic group, with a mean 25 months of follow-up. Kaplan-Meier long-term survival analysis did not reveal a difference between groups (log-rank p=0.37) once the perioperative period was survived. CONCLUSIONS Redo tricuspid valve repair for residual FTR can be performed with acceptable short-term and long-term mortality. However, treatment of FTR at the time of the initial intervention should be considered, because it is safe and effective. A randomized, controlled trial of prophylactic tricuspid operation for FTR at the time of the mitral operation may be warranted.

Training autonomous surgeons: more time or faculty development?

I t is of growing concern that residents are not prepared for independent practice upon completion of General Surgery training.1–6 Changes in duty hours and marked increased stringency in supervision standards has correlated with an increased failure rate on the certifying examination administered by the American Board of Surgery.7 When considering this current climate, Dr Frank R. Lewis, executive director of the American Board of Surgery, recently espoused a personal opinion that all residents should complete a fellowship following General Surgery residency to ensure that they are prepared for autonomous practice.6 Dr Lewis points to resident duty-hour restrictions as a major factor that has carved away approximately 2400 to 4800 hours of residency experiences, which equates to a loss of 6 to 12 months of training.6 In recognition of the issues of lost opportunities for graduated responsibility for surgical residents, the American Board of Surgery also recently added a requirement for a minimum of 25 teaching cases by graduating surgical residents as a proxy for some level of autonomy during training. At the present time, greater than 80% of graduating residents already complete a subspecialty fellowship program,8 but fellowship directors have also expressed frustration with the lack of readiness on arrival to fellowship to focus on the subspecialty content of the fellowship.1 The American College of Surgeons recently developed a postgraduate apprenticeship model of additional training for General Surgeons; however, it is too soon to determine if these “finishing programs” will gain traction with the 15% to 20% of General Surgery residents not currently pursuing subspecialty training. Although fellowships and additional time in training are likely an essential consideration, as we work toward a solution to this critical problem, we need to be cautious that we do not assume that simply adding additional time to training will address this emerging deficiency, and we must carefully examine the true root causes that have led to a lack of preparation for independent practice. It is certainly easy to point to the reduction of duty hours as a reason for the reduced experience and confidence of General Surgery residents upon graduation; however, we believe the problem is much more complex. Specifically, the degree of autonomy surgical residents experience in the operating room has significantly decreased over time due to many factors. These include, but are not limited to, duty-hour restrictions; increasing regulations that mandate more attending surgeon involvement and greater direct observation of residents; increased pressure on faculty surgeons to do more operations in less time; and more defined specialties within General Surgery— resulting in residents having exposure to numerous disciplines, but with little time to develop or demonstrate depth of ability with any

Inhaled Nitric Oxide to Improve Oxygenation for Safe Critical Care Transport of Adults With Severe Hypoxemia

BACKGROUND Inhaled nitric oxide (iNO) is a rescue treatment for severe hypoxemia in the intensive care unit setting. OBJECTIVE To evaluate the effectiveness and safety of iNO in adult patients with severe hypoxemia before and during transport to a tertiary care center. METHODS Prospective data were examined in a retrospective cohort study. Patients with severe hypoxemia and cardiopulmonary failure (n=139) at referring hospitals in whom conventional therapy was unsuccessful were treated with iNO in the intensive care units in anticipation of transfer to a tertiary center. Treatment wih iNO was initiated by the critical care transport team in 114 patients and continued in 25 patients. Arterial blood gas analysis was done before and after iNO treatment. RESULTS Patients treated with iNO had significant improvement in oxygenation: mean (SD) for PaO2 increased from 60.7 (20.2) to 72.3 (40.6) mm Hg (P=.008), and mean (SD) for ratio of PaO2 to fraction of inspired oxygen (P:F) increased from 62.4 (26.1) to 73.1 (42.6) (P= .03). Use of iNO was continued through transport in 102 patients, all of whom were transported without complication. The P:F continued to improve, with a mean (SD) of 109.7 (73.8) from 6 to 8 hours after arrival at the tertiary center (P< .001 relative to values both before and after treatment). Among patients treated with iNO, 60.2% survived to discharge. In 35 nonresponders, iNO was discontinued, and 15 patients could not be transferred owing to life-threatening hypoxemia; 2 were later transferred on extracorporeal membrane oxygenation. Of 18 patients transported without iNO, 9 (50%) survived. CONCLUSIONS Use of iNO significantly improves oxygenation of patients with severe hypoxemia and allows safe transfer to a tertiary care center.

Thromboembolic Events Before Esophagectomy for Esophageal Cancer Do Not Result in Worse Outcomes

BACKGROUND Esophageal cancer, chemotherapy, and radiation are all associated with an increased incidence of thromboembolic events (TEE). Development of a TEE during neoadjuvant treatment for esophageal cancer can alter the treatment course, as surgery may be delayed or cancelled because patients require anticoagulation therapy. We evaluated the incidence of preoperative TEE among esophageal cancer patients undergoing neoadjuvant treatment and the impact on morbidity, mortality, and timing of surgery. METHODS We performed a retrospective review of a prospectively collected database of 1,057 patients who underwent esophagectomy for esophageal cancer between January 1999 and May 2010. Of these patients, 534 were treated with neoadjuvant chemotherapy and radiation. RESULTS Preoperative thromboembolic events occurred in 75 of 534 patients (14.0%). The only preoperative factor associated with increased risk of TEE was increased preoperative weight (p=0.02). Fluorouracil significantly increased the risk of TEE (p=0.028, odds ratio 2.12, 95% confidence interval: 1.09 to 4.26), whereas there was no difference in patients receiving cisplatin (p=0.299). There was a trend toward an association between infectious complications during neoadjuvant therapy and TEE development (p=0.076). Patients with TEEs had a delay from neoadjuvant therapy to surgery (p=0.0004). The TEE group had a trend toward the increased onset of postoperative atrial fibrillation (p=0.0688, odds ratio 1.77, 95% confidence interval: 0.96 to 3.27). There was no difference in respiratory complications (p=0.934), overall complications (p=0.859), 30-day mortality (p=0.899), or overall survival (p=0.790). CONCLUSIONS Thromboembolic events in the preoperative period delay the time to surgery for patients with esophageal cancer. Despite this delay, there is no demonstrable effect on postoperative complications or mortality.

Lung Injury Prediction Score in Hospitalized Patients at Risk of Acute Respiratory Distress Syndrome.

Objective:The Lung Injury Prediction Score identifies patients at risk for acute respiratory distress syndrome in the emergency department, but it has not been validated in non-emergency department hospitalized patients. We aimed to evaluate whether Lung Injury Prediction Score identifies non-emergency department hospitalized patients at risk of developing acute respiratory distress syndrome at the time of critical care contact. Design:Retrospective study. Setting:Five academic medical centers. Patients:Nine hundred consecutive patients (≥ 18 yr old) with at least one acute respiratory distress syndrome risk factor at the time of critical care contact. Interventions:None. Measurements and Main Results:Lung Injury Prediction Score was calculated using the worst values within the 12 hours before initial critical care contact. Patients with acute respiratory distress syndrome at the time of initial contact were excluded. Acute respiratory distress syndrome developed in 124 patients (13.7%) a median of 2 days (interquartile range, 2–3) after critical care contact. Hospital mortality was 22% and was significantly higher in acute respiratory distress syndrome than non-acute respiratory distress syndrome patients (48% vs 18%; p < 0.001). Increasing Lung Injury Prediction Score was significantly associated with development of acute respiratory distress syndrome (odds ratio, 1.31; 95% CI, 1.21–1.42) and the composite outcome of acute respiratory distress syndrome or death (odds ratio, 1.26; 95% CI, 1.18–1.34). A Lung Injury Prediction Score greater than or equal to 4 was associated with the development of acute respiratory distress syndrome (odds ratio, 4.17; 95% CI, 2.26–7.72), composite outcome of acute respiratory distress syndrome or death (odds ratio, 2.43; 95% CI, 1.68–3.49), and acute respiratory distress syndrome after accounting for the competing risk of death (hazard ratio, 3.71; 95% CI, 2.05–6.72). For acute respiratory distress syndrome development, the Lung Injury Prediction Score has an area under the receiver operating characteristic curve of 0.70 and a Lung Injury Prediction Score greater than or equal to 4 has 90% sensitivity (misses only 10% of acute respiratory distress syndrome cases), 31% specificity, 17% positive predictive value, and 95% negative predictive value. Conclusions:In a cohort of non-emergency department hospitalized patients, the Lung Injury Prediction Score and Lung Injury Prediction Score greater than or equal to 4 can identify patients at increased risk of acute respiratory distress syndrome and/or death at the time of critical care contact but it does not perform as well as in the original emergency department cohort.

Increasing circulating sphingosine-1-phosphate attenuates lung injury during ex vivo lung perfusion

Background Sphingosine‐1‐phosphate regulates endothelial barrier integrity and promotes cell survival and proliferation. We hypothesized that upregulation of sphingosine‐1‐phosphate during ex vivo lung perfusion would attenuate acute lung injury and improve graft function. Methods C57BL/6 mice (n = 4‐8/group) were euthanized, followed by 1 hour of warm ischemia and 1 hour of cold preservation in a model of donation after cardiac death. Subsequently, mice underwent 1 hour of ex vivo lung perfusion with 1 of 4 different perfusion solutions: Steen solution (Steen, control arm), Steen with added sphingosine‐1‐phosphate (Steen + sphingosine‐1‐phosphate), Steen plus a selective sphingosine kinase 2 inhibitor (Steen + sphingosine kinase inhibitor), or Steen plus both additives (Steen + sphingosine‐1‐phosphate + sphingosine kinase inhibitor). During ex vivo lung perfusion, lung compliance and pulmonary artery pressure were continuously measured. Pulmonary vascular permeability was assessed with injection of Evans Blue dye. Results The combination of 1 hour of warm ischemia, followed by 1 hour of cold ischemia created significant lung injury compared with lungs that were immediately harvested after circulatory death and put on ex vivo lung perfusion. Addition of sphingosine‐1‐phosphate or sphingosine kinase inhibitor alone did not significantly improve lung function during ex vivo lung perfusion compared with Steen without additives. However, group Steen + sphingosine‐1‐phosphate + sphingosine kinase inhibitor resulted in significantly increased compliance (110% ± 13.9% vs 57.7% ± 6.6%, P < .0001) and decreased pulmonary vascular permeability (33.1 ± 11.9 &mgr;g/g vs 75.8 ± 11.4 &mgr;g/g tissue, P = .04) compared with Steen alone. Conclusions Targeted drug therapy with a combination of sphingosine‐1‐phosphate + sphingosine kinase inhibitor during ex vivo lung perfusion improves lung function in a murine donation after cardiac death model. Elevation of circulating sphingosine‐1‐phosphate via specific pharmacologic modalities during ex vivo lung perfusion may provide endothelial protection in marginal donor lungs leading to successful lung rehabilitation for transplantation.