Transition to Residency: The Successful Development and Implementation of a Nonclinical Elective in Perioperative Management

OBJECTIVE

Few medical school programs in Canada address challenges related to the significant increase in responsibility for patient care between medical school and residency. This is particularly important in surgery and anesthesia due to the high-acuity care required during the perioperative period. The purpose of this study was to develop and assess a program that would help students transition to surgical and anesthesia residencies, in terms of knowledge acquisition, clinical decision-making skills, and subjective preparedness.

DESIGN

The authors developed a 1-week nonclinical Perioperative Management Elective for students matching to surgical or anesthesia residencies. Clinical decision-making training was incorporated using a simulated pager called the MedsOnCall Pager app. A study was conducted to evaluate knowledge acquisition and development of clinical decision-making skills in students completing the elective. A mixed-effects model analysis of the proportion of pages answered correctly during the elective was used as a marker of their progression. Students were asked to complete entry and exit questionnaires to provide subjective information regarding their elective experience.

SETTING

The study ran for 2 iterations of the elective in 2016 and 2017 at the University of Ottawa.

PARTICIPANTS

A total of 20 University of Ottawa fourth-year medical students completed the elective.

RESULTS

There was a significant increase in the proportion of correctly answered pages over the course of the elective week (p = 0.04). Results from entry and exit questionnaires revealed that students felt more knowledgeable, comfortable, and prepared for residency after completing the elective (p < 0.001).

CONCLUSIONS

The Perioperative Management Elective has completed 2 successful iterations with confirmed knowledge acquisition and improved clinical decision-making skills among elective students. Participating students perceived that the experience was beneficial and fulfilled a gap in their medical school training. We believe that this elective framework could be employed by other schools to help graduating students' transition smoothly into residency.

Coronary Surgery in Women and the Challenges We Face

This review was undertaken to understand the dynamics that have shaped our current treatment of women who undergo coronary artery bypass grafting (CABG) and summarize the current literature on surgical revascularization in women. There has been improved access to CABG over the past several decades. Despite this, compared with men, CABG in women involves fewer grafts and less frequent use of arterial grafts, the latter having improved long-term patency compared with saphenous vein grafts. We attempt to determine whether the adverse clinical profile of women, when referred for CABG is responsible for this finding. Female coronary anatomy and pathophysiology are reviewed and an attempt is made to understand how this might affect decisions of selection and outcome measures post CABG. We review the short-term, long-term, and quality of life outcomes in women. These data are taken from large databases, as well as from more recent publications. Randomized controlled trial data and meta-analytic data are used when available. Differential use of and outcomes of surgical strategies, including off-pump CABG and total arterial revascularization, are contrasted with those in men. This review shows that there continues to be widespread differences in surgical approach to coronary artery disease in female vs male patients. We provide evidence suggestive of the existence of issues specific to women that affect selection for surgical procedures and outcomes in women. More work is required to understand the reason for these differences and how to optimize sex-specific outcomes.

Practice meta-environment of the cardiovascular perfusionist

Though historically the development of cardiovascular perfusion grew out of the need for cardiopulmonary bypass, the application of technologies of extracorporeal support has more recently expanded beyond the traditional domain of the cardiac surgical operative and peri-operative environment. As a result, perfusionists are sometimes required to work in novel clinical settings. As part of our recent national survey to evaluate the effects of changes in entry-to-practice criteria introduced in Canada in 2006, we asked perfusionists if their current position as a perfusionist involves work outside the OR. We found that, in addition to regularly working in the Intensive Care Unit and Cardiac Catheterization Lab, 55.3% of respondents reported working "occasionally" in the Emergency Room and 74.7% reported working "occasionally" or "often" in other clinical areas. However, while 96% of respondents believed their training adequately prepared them for their job as a perfusionist, only 68% felt their training adequately prepared them for their duties outside the operating room. We also noted a trend that admission under experience-based entry-to-practice criteria was associated with a higher likelihood of perceived adequacy of training in preparation for duties outside the OR than education-based admission criteria (72% vs 59.4%, p=0.065). These findings raise important questions pertaining to the sufficiency of perfusion education in Canada and the influence of soft skills in preparing perfusionists for their duties, and indicate that a systematic study of the practice environment of cardiovascular perfusionists is timely.

Development of a high fidelity pressurized porcine beating heart simulator for cardiac surgery training

BACKGROUND

Development of a high-fidelity cardiac surgery simulator (CSS) requires integration of a heart model with a mock cardiopulmonary bypass (CPB) circuit that can provide feedback to mimic the pathophysiology of cardiac surgery. However, the cost of commercially available simulators precludes regular use. We describe steps in the construction of a high-fidelity CSS that integrates a pulsatile paracorporeal ventricular-assist device (Pulse-VAD) and a commercially available CPB simulator.

METHODS/RESULTS

Eight porcine hearts were initially prepared. The configuration consisted of cannulation of the distal descending aorta and the inferior vena cava to enable pressurization of the heart after connection to the Califia^® simulator, as well as Pulse-VAD cannulation (fitted with inflatable balloons) of both ventricles. After each simulation run, the team addressed key issues to derive successive model changes through consensus. Key modifications included: a) pressure maintenance of the cardiac chambers (removal of lungs, Pulse-VAD cannulation sites at the left pulmonary artery and vein, double ligation of arch vessels); b) high-fidelity beating of both ventricles (full Pulse-VAD bladder filling and ensuring balloon neck placement at the valvular plane) and c) reproducible management of porcine anatomy (management of porcine aorta, ligation of left azygous vein and shortened ascending thoracic aortic segment).

CONCLUSION

A CSS can be prepared at low cost, with integration into a high-fidelity CPB simulator with a novel beating heart component. This setup can be used in teaching the basics of CPB techniques and complex surgical procedures. Future work is needed to validate this model as a simulation instrument.

Should We Ablate Atrial Fibrillation During Coronary Artery Bypass Grafting and Aortic Valve Replacement?

BACKGROUND

This study evaluates the safety and efficacy of concomitant atrial fibrillation (AF) ablation in patients with AF undergoing coronary artery bypass grafting (CABG) or aortic valve replacement (AVR) or both.

METHODS

This is a single-center retrospective study of patients with AF presenting for CABG or AVR or both between 2009 and 2013. They were divided into an ablation group that underwent concomitant AF ablation and a control group that did not. Follow-up data were obtained using telephone interviews. The data were 100% complete with a median follow-up of 30 months.

RESULTS

A total of 375 patients with AF presented for CABG (44%), AVR (27%), or CABG and AVR (29%). The ablation (129 patients) and control (246 patients) groups had similar baseline characteristics. The ablation group had significantly longer cardiopulmonary bypass and cross-clamp times, adding a mean of 31 ± 3 and 22 ± 3 minutes (p < 0.01 for both), respectively. There were similar unadjusted rates of hospital mortality (4.7% versus 5.3%, p = 0.79), stroke (3.1% versus 3.3%, p = 0.94), and reopening (4.7% versus 6.5%, p = 0.46) between the groups. The intensive care and hospital length of stays were similar. The ablation group had a lower incidence of postoperative AF (27% versus 78%, p < 0.01). Adjusted operative mortality was similar, but the intervention group had significantly lower odds of postoperative AF (odds ratio 0.11, p < 0.01). Although there was no difference in mid-term survival, the ablation group had higher mid-term AF-free survival (p < 0.01) and a trend toward higher anticoagulation-free (p = 0.09) and stroke-free survival (p = 0.08).

CONCLUSIONS

Concomitant AF ablation in patients with AF undergoing CABG or AVR or both does not increase perioperative rates of mortality or morbidity. Moreover, concomitant AF ablation is effective at reducing postoperative AF burden and increases mid-term AF-free survival.

The inflammatory response to cardiopulmonary bypass: a therapeutic overview

The demographic of cardiac surgery patients continues to evolve to include older, sicker candidates, all the while maintaining an expectation of excellent outcomes. These latter results can only be achieved by the parallel advancement and re-examination of the technology of cardiopulmonary bypass (CPB); the key tool used daily by surgical teams worldwide. In this review, we will provide an overview of integrated therapeutic strategies that can be utilized to minimize the complex and myriad changes related to inflammation after CPB with the understanding that this may abrogate the detrimental end-organ and systemic effects of blood activation. Therapeutic strategies specifically related to the technology can be classified into those targeting biomaterial dependent or independent processes. The former can be addressed by the utilization of currently available biocompatible surfaces such as with heparin-coated circuits, phosphorylcholine-coated circuits (‘biomembrane mimicry’) and circuits composed of copolymers containing surface-modifying additives. The most important strategies related to biomaterial independent activation include the modification of techniques related to cardiotomy blood management and blood filtration. Finally, all of these strategies must be integrated and tailored with complementary pharmacologic agents such as aprotinin and steroids to optimize anti-inflammatory synergism. Only if we are armed with a comprehensive knowledge of the molecular and cellular basis for these strategies will we be able to continue to evolve our treatment in parallel with our patients to achieve these goals.

Effects of a change in entry-to-practice criteria for cardiovascular perfusion in Canada: results of a national survey

INTRODUCTION

Years of experience and level of education are two important determinants of a clinician's expertise. While entry-to-practice criteria for admission to perfusion training in Canada changed from clinical experience-based criteria to education-based criteria in 2006, the effects of these changes have not been studied.

OBJECTIVE

To determine the academic and clinical backgrounds of perfusionists in Canada, ascertain perceptions about the adequacy of training and evaluate the effects of the changes on the composition of the perfusion community of Canada.

METHODS

An electronic questionnaire was distributed to all practicing perfusionists in Canada, addressing details regarding clinical experience, academic education and perceptions about the adequacy of training.

RESULTS

Two hundred and twenty-eight questionnaires were completed, representing a 72% response rate. Perfusionists admitted under academic-based criteria have significantly higher levels of education (100% degree holders vs 69.1%, p<0.001), but less antecedent clinical training and experience (median, IQR: 0, 0 - 4.5 years vs 2, 2 - 8 years, p<0.0001), are younger (median age range 31-35 years vs 51-55 years, p<0.0001), more likely to be female (58.7% vs 41.3%, p=0.006) and are significantly more likely to enter perfusion because of attraction to the type of work (p=0.045). Many perfusionists (70, 32%) in Canada believe themselves inadequately trained for their clinical assignments outside the OR. In addition, 19% of perfusionists plan to retire over the next 10 years.

CONCLUSIONS

The introduction of education-based entry criteria has changed the academic and clinical experience levels of perfusionists in Canada. Strategies designed to better prepare perfusionists for their clinical assignments outside the OR are merited.

Lessons learned on the path to a healthier brain: dispelling the myths and challenging the hypotheses

Neurologic dysfunction remains the most significant complication associated with cardiopulmonary bypass (CPB). The insidious change of cognitive decline has been perceived as a key factor that has contributed to the shift to percutaneous intervention for coronary disease. Current neuropsychologic testing provides the most sensitive means of demonstrating clinically relevant cerebral damage of this nature. Through extensive experience in randomized clinical trials of over 900 patients undergoing CPB, our team has addressed several key hypotheses related to the embolic/ischemic nature of cerebral injury in cardiac surgery, using this testing. In the first temperature study, patients randomized to hypothermia with passive re-warming had a lower incidence of neurocognitive deficit when compared with those patients who were actively re-warmed to 37°. In order to clarify the role of the hypothermia as opposed to the re-warming process, a second temperature study was completed. In the hypothermic group, patients were cooled and maintained at 34° with no active re-warming whereas, in the normothermic group, the patients were kept at 37° throughout the perioperative period. No difference in neurocognitive outcome in the two groups was seen, implying that the benefit seen in the first temperature study was related not to the hypothermia, but rather to the absence of active re-warming. In the cardiotomy study, patients were randomized to either a control group in which their cardiotomy blood was returned unprocessed, or a treatment group in which this blood was sequestered and processed with centrifugal washing and fat filtration. No significant difference in neurocognitive outcome was found in these two groups. On the other hand, there was a significant increase in bleeding and transfusion requirements in the treatment group. Many of our daily practices in CPB management are based upon assumptions from observational studies without sound reference to evidence-based medicine. Our recent studies have challenged our assumptions related to ischemia and embolic events during CPB. They have also confirmed that, when high standards in trial design are applied, the results can have universal implications in terms of our practice. Perfusion (2007) 22, 153—160.

Are we doing everything we can to conserve blood during bypass? A national survey

Introduction: Despite major advances in biomaterial research and blood conservation, bleeding is still a common complication after cardiopulmonary bypass and cardiac surgery remains a major consumer of blood products. Although the underlying mechanisms for these effects are not fully established, two proposed major etiologies are the hemodilution associated with the use of the heart-lung machine and the impact of reinfusion of shed cardiotomy blood. Therapeutic strategies that primarily encompass the use of devices or technologies to overcome these effects may result in improved clinical outcomes.

Objective: To determine the extent to which 1) lipid/leukocyte filtration and centrifugal processing of cardiotomy blood, and 2) modified ultrafiltration (MUF) are currently applied in adult cardiac surgery in Canada.

Methods: A questionnaire was mailed to the chief perfusionist at all adult cardiac surgical centers in Canada, addressing details regarding the frequency of use of cardiotomy blood processing and MUF.

Results: All questionnaires (36, 100%) were completed and returned. With regards to cardiotomy blood management, in 21 centers (58%), no specific processing steps were utilized exclusive of the integrated cardiotomy reservoir filter. Of the remaining centers, two (6%) reported using lipid/leukocyte filtration and 15 (42%) reported washing their cardiotomy blood. Three centers (8%) reported using MUF at the end of CPB.

Conclusions: Despite growing concern about the potential detrimental effects of cardiotomy blood, few centers in Canada routinely manage this blood with additional filtration and/or centrifugal processing prior to reinfusion. Similarly, MUF, demonstrated to be effective in the pediatric population, has not seen popular application in adult cardiac surgical practice.

Clinical and mechanical factors associated with the removal of temporary epicardial pacemaker wires after cardiac surgery

BACKGROUND

Temporary pacemaker wires are placed in the majority of patients after cardiac surgery. There is no information on mechanical factors related to wire removal.

METHODS

Clinical information related to temporary wire use and removal was prospectively collected from a large cardiac surgical unit over one year. Measurements of maximal tension that nurses and doctors would apply to remove temporary wires was determined using a hand-held portable scale. In a prospective trial, patients (n = 41) had their wires extracted in series to the portable scale to determine the maximal tension required for safe removal.

RESULTS

Ventricular wires were placed in 86.5 % of patients during the observed year. Pacing facilitated weaning from CPB in over 15 % of patients and pacer dependence was seen in 2.1 %. No patients suffered major complications after wire removal. There was no difference in the tension that physicians or nurses would apply to comfortably extract temporary wires. In the prospective trial, there was no difference in the tension required for removal of atrial or ventricular wires (atrial 18.3 ± 17.9 oz versus 14.5 ± 14.2 oz, p = 0.430). There were no patient factors that correlated with the degree of resistance and there was no significant difference between the tension required to remove wires with (21.0 ± 22.5 oz) or without (14.1 ± 5.1 oz) an atrial button.

CONCLUSIONS

Temporary epicardial wire removal is innocuous and was not associated with any complications. In some patients tension required for safe removal exceeded 20 ounces. Strategies to standardize wire removal may prevent complications and may minimize unnecessary wire retention.

Assessment of the Impact of Skeletonization on Pleuropulmonary Changes after Bilateral Internal Thoracic Artery Harvest for Coronary Artery Bypass Grafting

BACKGROUND AND AIMS

Skeletonization has been proposed as a technique to minimize the risk of sternal devascularization during bilateral internal thoracic artery harvest for coronary artery bypass grafting. The impact of this strategy on late radiologic pleuropulmonary changes has not been addressed.

MATERIAL AND METHODS

Post-operative chest radiographs from patients (n = 253 per group) undergoing bilateral internal thoracic artery harvest using skeletonized and non-skeletonized techniques were reviewed by blinded radiologists. The primary outcome was the incidence of atelectasis and pleural effusion. Multivariable linear regression models were derived to assess the relationship of radiologic pleuropulmonary outcomes to patients and operative variables.

RESULTS AND CONCLUSION

Patients in the skeletonized group were older (p < 0.0001), had a lower preoperative hematocrit (p = 0.014), had higher prevalence of peripheral vascular disease (p = 0.001), were of female gender (p = 0.015), underwent off-pump surgery (p < 0.001), had urgent/emergent status (p = 0.024), and had chronic obstructive pulmonary disease (p = 0.019). There was no difference in the incidence of post-operative complications, ventilation time, or intensive care unit stay. There was no difference in the severity of post-operative atelectasis in both groups. More patients in the non-skeletonized group had a grade 2/3 left pleural effusion on the late post-operative chest X-ray (p = 0.007). The independent effect of skeletonization on the development of a late left pleural effusion was significant (odds ratio = 0.558, 95% confidence interval = 0.359-0.866, p = 0.009). Skeletonization results in a decreased incidence of late post-operative left pleural effusion with no difference in early or late atelectasis. Further studies are warranted to assess the mechanism of these pleuropulmonary changes and the impact of other factors such as pleural violation during surgery.

Assessment of the Association of Bilateral Internal Thoracic Artery Skeletonization and Sternal Wound Infection After Coronary Artery Bypass Grafting

BACKGROUND

Skeletonization is a technique of bilateral internal thoracic artery (BITA) harvest that preserves sternal blood flow. We sought to identify the relationship of skeletonization and sternal wound infection in a population undergoing BITA harvest.

METHODS

Demographics and outcomes were recorded from patients undergoing coronary artery bypass graft surgery with BITA using either skeletonized (n = 531) or nonskeletonized (n = 970) techniques. The primary outcome was total infection. Propensity scores analysis as well as univariable and multivariable analysis was performed to determine the effect of skeletonization in the total cohort and in each sex.

RESULTS

Although patients undergoing skeletonized BITA had a lower body mass index, they were significantly older, with a higher proportion of women, diabetes mellitus, urgent or emergent surgery, renal failure, vascular and lung disease, and lower preoperative hemoglobin. There was a significant effect of skeletonization in decreasing total infection incidence (odds ratio [OR] 0.606, 95% confidence interval [CI]: 0.383 to 0.959, p = 0.032). The effect of skeletonization on total infection in men was more prominent (OR 0.466, 95% CI: 0.290 to 0.870), whereas there was no effect in women (OR 0.887, 95% CI: 0.441 to 1.786). Multivariable analysis confirmed that skeletonization was protective (OR 0.606, 95% CI: 0.383 to 0.957, p = 0.032). Other factors associated included being female (OR 3.327, 95% CI: 2.080 to 5.322, p < 0.001), insulin-dependent diabetes mellitus (OR 2.638, 95% CI: 1.506 to 4.624, p = 0.001), peripheral vascular disease (OR 2.101, 95% CI: 1.247 to 3.539, p = 0.005), increased body mass index (OR 1.100, 95% CI: 1.054 to 1.149, p < 0.001), and decreased preoperative hemoglobin (OR 0.984, 95% CI: 0.972 to 0.997, p = 0.013).

CONCLUSIONS

Skeletonization is associated with a significant protective effect with regard to sternal infection after coronary artery bypass graft surgery with BITA. Being female is a major risk factor for infection, and the risk is not modified significantly with a strategy of skeletonization in women.

A Matched-Paired Comparative Analysis of the Hemodynamics of the Trifecta and Perimount Aortic Bioprostheses

BACKGROUND AND AIM OF THE STUDY

Current cohort studies comparing the Trifecta valve to alternative pericardial bioprostheses are limited by selection bias. The study aim was to determine if hemodynamics are improved after the aortic valve implantation of a Trifecta valve as compared to a standard pericardial valve, when evaluated using strict paired matching for specific key relevant confounders.

METHODS

Valve hemodynamics were compared in patients undergoing implantation with a Trifecta or Perimount valve matched for left ventricular outflow tract (LVOT) diameter, gender, age, body size, and days since surgery, using a 1:1 matched-paired cohort analysis (n = 20 per group).

RESULTS

Patients receiving a Trifecta valve had a larger increase in indexed stroke volume (SVi) relative to baseline compared to the Perimount patients (p = 0.013), in whom SVi was decreased. The mean transvalvular pressure gradient was lower in Trifecta patients despite the larger SVi (p = 0.02). The effective orifice area (EOA) and indexed EOA (EOAi) were significantly larger in Trifecta patients compared to Perimount patients (2.04 +/- 0.46 versus 1.77 +/- 0.45 cm2, p = 0.049; 1.10 +/- 0.22 versus 0.95 +/- 0.06 cm2/m2, p = 0.027, respectively), and there was a greater increase in EOA and EOAi from baseline (p = 0.010 for both). Severe prosthesis-patient mismatch (PPM) (EOAi < or = 0.65 cm2/m2) was seen in two (10%) of the Perimount cases, but in none of the patients with the Trifecta valve (p = 0.072).

CONCLUSION

Trifecta valve implantation is associated with a significant improvement in EOA and a decreased incidence of PPM as compared to the Perimount valve. The superior hemodynamic outcomes observed support consideration of this valve for aortic valve replacement, particularly in patients with a small LVOT at risk for PPM.

Preventive strategies for atrial fibrillation after cardiac surgery in Nordic countries

BACKGROUND AND AIMS

Atrial fibrillation is a common arrhythmia after cardiac surgery. It increases morbidity, length of hospital stay, and costs of operative treatment. Beta-blockers, sotalol, amiodarone, corticosteroids, and biatrial pacing have been shown to be efficient in the prevention of postoperative atrial fibrillation. The aim of this study was to find out how widely different prophylactic strategies for postoperative atrial fibrillation are used in Scandinavian countries.

MATERIAL AND METHODS

An online link for a questionnaire was emailed to (214) cardiac surgeons in Finland, Sweden, Norway, Denmark, and Estonia to assess the use of prophylactic methods for postoperative atrial fibrillation.

RESULTS

A total of 97 surgeons responded to the survey. Oral beta-blockers were routinely used for atrial fibrillation prophylaxis by 62% of responders. The main reasons for nonuse of beta-blockers were that responders were unconvinced of the evidence of benefit or they preferred some alternative prophylaxis. Intravenous beta-blockers were used frequently by 6% of responders. Amiodarone was used for prophylaxis by 18% of responders. Nonusers were unconvinced of its efficacy, were afraid of its complications, or found its use too cumbersome. Other prophylactic atrial fibrillation strategies that were used are as follows: sotalol by 2%, magnesium by 17%, corticosteroids by 1%, and atrial pacing by 11% of respondents.

CONCLUSIONS

There is still widely varying implementation of strategies for atrial fibrillation prophylaxis among Scandinavian cardiac surgeons. Lack of confidence in the efficacy of these approaches is the main rationale for nonimplementation.

Currently available biomaterials for use in cardiopulmonary bypass

Cardiopulmonary bypass (CPB) represents one of the most important technical innovations in healthcare history, yet the systemic responses to CPB remain a fundamentally unresolved problem. Study of the blood-biomaterial interaction and development of biocompatible materials is intimately related to efforts to optimize patient outcome following CPB. This article reviews the design innovations in biomaterial surfaces that have been introduced into clinical practice in an attempt to ameliorate the detrimental consequences of CPB, contrasting the actual clinical improvements and patient benefits achieved against those predicted on the basis of theory and in vitro testing. Some discussion of the underlying mechanisms of action as presently understood is provided and the current limitations of biomaterial-dependent strategies to improve outcome following CPB are addressed.