Perfusion

Due to the emergent unpredictable nature of cardiac surgery, perfusionists, potentially, are susceptible to extended work hours and acute sleep deprivation. While fatigue among other healthcare clinicians has been studied, there has been no research on this topic specifically in the perfusion community. Therefore, the purpose of this study was to: (1) collect preliminary data on the prevalence of fatigue in perfusion and (2) identify if there were concerns regarding fatigue, performance and perfusion safety.

In May 2010, a link to a 50-question survey (surveymonkey.com) was posted on Perflist and Perfmail. The survey was closed in July 2010. There were 445 respondents and data were analyzed and expressed as a response percent.

Participants included 27% chief perfusionists/managers, 67% staff perfusionists, and 6.0% other (perfusion education faculty, retired perfusionists, locum tenens). Regarding extended work hours, 68.9% of surveyed perfusionists have worked at the hospital for greater than 23 hours straight and 17.5% have worked continuously for over 36 hours. Actual performance of cardiopulmonary bypass (CPB) after 17, 23, and 36 hours of wakefulness was reported by 82.9%, 63% and 14.8% respondents, respectively. Regarding bathroom requirements while on CPB, 87.5% have felt extremely uncomfortable at least once, 19.9% have relieved themselves in the operating room at least once, and 22.3% have left the pump attended by a non-perfusionist to use the restroom at least once. Microsleep during CPB was reported by 49.5% of respondents. Automobile accidents attributed to an extended period of work and fatigue was reported by 6.9% and another 44.4% reported a near-miss auto accident. A fatigue-related minor error was reported by 66% and 6.7% admit to having a serious perfusion accident believed to be due to fatigue. Concerning critical phases of bypass, 51.5% believe that they perform less effectively when fatigued. Additionally, 75.9% indicate that they have been concerned about their ability to perform their job adequately due to fatigue-related acute sleep deprivation. Opinions regarding workplace management were as follows; 48% believe that fatigue can play a role in our profession and managers should do what they can to provide a rested staff, but, unfortunately, it is impractical to set work limits; 32.2% believe fatigue issues should be taken more seriously and specific guidelines should be stated by our professional organizations and 13.4% believe that limits should be established, legislated, and enforced by state or federal authorities.

Based upon this preliminary survey data, it appears that fatigue and acute sleep deprivation is a significant safety concern in the perfusion community. Further research must be performed to understand actual performance degradation that may occur in fatigued perfusionists performing CPB.

Cell phone use in the U.S. has increased dramatically over the past decade and text messaging among adults is now mainstream. In professions such as perfusion, where clinical vigilance is essential to patient care, the potential distraction of cell phones may be especially problematic. However, the extent of this as an issue is currently unknown. Therefore, the purpose of this study was to (1) determine the frequency of cell phone use in the perfusion community, and (2) to identify concerns and opinions among perfusionists regarding cell phone use.

In October 2010, a link to a 19-question survey (surveymonkey.com) was posted on the AmSECT (PerfList) and Perfusion.com (PerfMail) forums. There were 439 respondents. Demographic distribution is as follows; Chief Perfusionist (30.5%), Staff Perfusionist (62.0%), and Other (7.5%), with age ranges of 20-30 years (14.2%), 30-40 years (26.5%), 40-50 years (26.7%), 50-60 years (26.7%), >60 years (5.9%).

The use of a cell phone during the performance of cardiopulmonary bypass (CPB) was reported by 55.6% of perfusionists. Sending text messages while performing CPB was acknowledged by 49.2%, with clear generational differences detected when cross-referenced with age groups. For smart phone features, perfusionists report having accessed e-mail (21%), used the internet (15.1%), or have checked/posted on social networking sites (3.1%) while performing CPB.

Safety concerns were expressed by 78.3% who believe that cell phones can introduce a potentially significant safety risk to patients. Speaking on a cell phone and text messaging during CPB are regarded as “always an unsafe practice” by 42.3% and 51.7% of respondents, respectively. Personal distraction by cell phone use that negatively affected performance was admitted by 7.3%, whereas witnessing another perfusionist distracted with phone/text while on CPB was acknowledged by 33.7% of respondents.

This survey suggests that the majority of perfusionists believe cell phones raise significant safety issues while operating the heart-lung machine. However, the majority also have used a cell phone while performing this activity. There are clear generational differences in opinions on the role and/or appropriateness of cell phones during bypass. There is a need to further study this issue and, perhaps, to establish consensus on the use of various communication modes within the perfusion community.

Volatile anaesthetic agents are widely used for maintenance of anaesthesia in all kinds of surgical procedures. Despite the implementation of measures such as adequate ventilation of the operating room and the use of efficient scavenging systems, concern remains about the risks for occupational exposure, especially in situations associated with an increased risk of anaesthetic gas waste, such as with the use of volatile anaesthetic agents on cardiopulmonary bypass. The present contribution reports the results of a preliminary safety assessment involving measurements of sevoflurane concentrations in the ambient air of a cardiac surgery operating room.

In 22 cardiac surgical procedures with cardiopulmonary bypass (11 with open and 11 with closed venous reservoir), measurements of trace concentrations were obtained every 10 min at the following sites: at the outlet of the oxygenator, at the outlet of the cardiotomy reservoir, in the breathing zone of the perfusionist and above the surgical field. The concentrations were measured on-line using a photoacoustic infrared spectrometer.

Mean sevoflurane waste concentrations remained consistently below the recommended target value of 4.68 ppm throughout the observation period at the different measurement sites.

These results indicate that, with the use of sevoflurane on cardiopulmonary bypass, the recommended levels for occupational exposure are not exceeded, provided adequate operation room ventilation and waste gas scavenging is performed.

The new Perfusion Simulation Center at the Medical University of South Carolina provides a new level of high fidelity simulation training for perfusion students. A key component is the Orpheus Perfusion Simulator which is a computer-driven simulator integrated with the mechanical connections of the heart-lung machine to allow for real time operative procedures and perfusion incidents. Due to the ability to consistently reproduce cardiac surgical scenarios, it is possible to develop both basic perfusion skills as well as advanced emergency skills more effectively than with animal models. The purpose of this paper is to provide details about advanced simulation for perfusionists and to illustrate how simulation can be used to promote the assets of good communication, team work, and surgical awareness. Two sets of four cardiac surgical scenarios were recorded in the perfusion simulation operating room. Scenario team member roles included a cardiac surgeon, an anesthesiologist, a perfusionist and an operating room nurse. The scripted surgical scenarios were viewed by a focus group of students charged with identifying key personality traits of different members of the operating team and to characterize them using a list of descriptive words adapted from the Medical University of South Carolina’s Peer Review Tool. In the first set of scenarios, initial scores were negative, with irresponsibility, impatience, and carelessness listed as the top behavioral characteristics leading to human error. In the second set of scenarios, logical, clear-thinking, and attentive were the most common personality traits observed of the effective team members. Simulation has become an invaluable tool for perfusion education and the goal of improving patient safety during cardiopulmonary bypass. The opportunities for advanced training in the perfusion simulation environment will certainly expand in the future.

Introduction: This study was performed to determine the clinical application of rest 99mTc-sestamibi in the assessment of viability and functional improvement of the left ventricle (LV) myocardium in the post-thrombolytic therapy of acute myocardial infarction (AMI). Material and methods: In 37 patients with AMI who received thrombolytic therapy, 2-dimensional (2D) echocardiography, as well as the resting redistribution of 99mTc-sestamibi, was investigated, both within 1 week and 3–5 months after AMI. The predictive capacity of the perfusion percentage for myocardial function recovery was evaluated. Also, the capacities of the possible variables in the prediction of recovery of myocardial function resulting from a change in LV ejection fraction (EF) were evaluated using stepwise multiple regression analysis. Results: Thirty-seven patients (30 men and 7 women; mean age: 58±14 years) with AMI were enrolled in the study. Redistribution was observed in 35 and 50 segments of the initial and follow-up scans, respectively. In addition, 146 segments with reverse redistribution (RR), both in the initial scan (118 segments) and the follow-up scan (86 segments), were also observed. An apparent difference in wall motion scores was seen between the initial and follow-up echocardiographs (p<0.001). Furthermore, using the optimal cut-off point of perfusion percentage in each image set, sensitivity as well as specificity and likelihood ratio (LR) for the improvement of regional wall motion after 3–5 months were defined. Conclusion: These data showed that redistribution and reverse redistribution of 99mTc-sestamibi post thrombolytic therapy can be used as a marker of viability to predict the recovery of segmental wall motion abnormality (stunning), as well as the improvement of segmental perfusion uptake. This study also demonstrates that the resting 99mTc-sestamibi SPECT can be used for an approximate assessment of LV function status and can predict the recovery of jeopardized myocardium function after thrombolytic therapy.

Background: Mild to moderate systemic hypothermia is commonly used as a cerebral protective strategy during adult cardiac surgery. The benefits of this strategy for routine cardiac surgery have been questioned and the adverse effects of hyperthermia demonstrated. The purpose of the present study was to examine current temperature management and monitoring practices during adult cardiac surgery using CPB in Canada.

Methods: Web-based survey referring to adult cases undergoing cardiac surgery using CPB without the use of deep hypothermic circulatory arrest. Thirty-two questionnaires were completed, representing a 100% response rate.

Results: The usual management is to cool patients during CPB at 30 (94%) centers for low-risk (isolated primary CABG) cases and at 31 (97%) centers for high-risk (all other) cases. The average nadir temperature at the target site achieved on CPB is 34°C (range 28°C - 36°C). At 26 (81%) centers, patients are typically rewarmed to a target temperature between 36°C and 37°C before separation from CPB. Only 6 (19%) centers reported that thermistors and coupled devices used to monitor blood temperature are checked for accuracy or calibrated according to the product operating directive’s schedule or more often.

Conclusions: Contemporary management of adult cardiac surgery under CPB still involves induction of mild to moderate systemic hypothermia. Significant practice variation exists across the country with respect to target temperatures for cooling and rewarming, as well as the site for temperature monitoring. This probably reflects the lack of definitive evidence. There is a need for well-conducted clinical trials to provide more robust evidence regarding temperature management.

Objective: The aim of our study was to assess the long-term clinical outcomes and the grafts patency rates of patients with ST-segment elevation myocardial infarction (STEMI) who underwent urgent or emergency coronary artery bypass grafting (CABG).

Materials: Participants in two previous studies comprising 207 STEMI patients undergoing on-pump (145 patients) or off-pump (62 patients) coronary artery bypass graft (CABG) surgery in our institution were prospectively followed to assess late mortality, graft patency, and major adverse cardiac-related event (MACE) rates. Graft patency was evaluated by multi-detector computed tomography angiography 64-slice scan. Mean times of graft implantation were 38±16 months and 37±14 months in on-pump and off-pump, respectively. Follow-up data were obtained in all patients and was 100% complete.

Results: Late mortality rate was 7.4% (10 patients) in the on-pump and 6.5% (4 patients) in off-pump groups (p=0.45). Five-year overall survival rate (±SE) was 93.5±2.1% and 92.6±1.9% in the off-pump vs on-pump, respectively. Five years’ freedom from cardiac-related death was 94.9±2.9% in the on-pump group vs 96.8±3.2% in the off-pump group (p=0.25). Five years’ freedom from cardiac-related events was 89.7±1.6% in the on-pump group versus 93.5±1.8% in the off-pump group (p=0.32). In all patients, a total of 449/491 (91.5%) grafts were patent. Percentages of overall grafts classified as patent were similar in the on-pump group (90.7% - 322/355 conduits) versus the off-pump group (91% - 133/146 conduits). Graft patency rates were also similar between the two groups with regard to arterial and saphenous vein conduits, and with regard to different branches of the coronary arteries grafted.

Conclusion: Our data suggest that off-pump CABG patients have the same late mortality, MACEs, and graft patency rates as conventional cardioplegic cardiac arrest CABG patients. In our opinion, urgent or emergency CABG for patients with STEMI can be done either way.

Our objective was to investigate the in vitro effects of a totally balanced fluid concept on whole blood coagulation. Venous blood from 12 healthy volunteers was diluted by 20% and 40% with a combination of an equal amount of colloid (balanced or unbalanced 6% HES 130/0.4, or 4% gelatin) and crystalloid (balanced or unbalanced Ringer’s acetate). Blood samples were analyzed with rotational thromboelastometry (ROTEM®).

The initiation of coagulation was delayed in all dilutions except for the 20 vol% gelatin-dilution. In the extrinsic activation test, maximum clot firmness was decreased and clot formation time prolonged after 40 vol% hemodilution with a balanced Ringer’s/unbalanced HES combination, more than in the corresponding gelatin hemodilution. In the fibrin-based test, after both 20- and 40 vol% hemodilution with unbalanced Ringer’s/gelatin solution, maximum clot firmness was significantly stronger than in the Ringer’s/HES-combinations.

The combination of balanced colloid and crystalloid has similar coagulation effects in vitro as their respective combination of unbalanced solutions.

The ideal cardioplegic strategy in thoracic aorta operations requiring long cardiopulmonary bypass and cross-clamp time has not been established. Suboptimal myocardial protection may lead to myocardial damage and possible post-operative complications. We evaluate post-operative cardiac Troponin I (cTnI) release, low cardiac output syndrome (LCOS) and mortality, using a cold crystalloid single-dose intracellular or cold blood multidose cardioplegia in 112 elective or emergent thoracic aorta operation patients. Fifty-four patients (HTK group) received Custodiol® cardioplegic solution and 58 received cold blood cardioplegia (CB group). Cross-clamp time, cardiopulmonary bypass (CPB) time and cTnI peak release were similar in both groups. No differences were found for atrial and ventricular arrhythmias, inotropic support, LCOS and in-hospital mortality. Two-way ANOVA analysis revealed an interactive effect on cTnI peak (p=0.012) of cardioplegic solution type across the cross-clamp time quintile. In the fifth quintile, cross-clamp time patient (>160 min) cTnI peak value was higher in CB patients (p=0.044). HTK and CB cardioplegic solutions assure similar myocardial protection in patients undergoing thoracic aorta operations. In long cross-clamp times, the lower post-operative cTnI release detected using HTK may be indicative of a better myocardial protection in these extreme conditions.

An innominate truncal dissection and rupture into the right pleural cavity with massive hemothorax is the initial presentation in this 66-year-old lady with type A dissection of the aorta complicated by right coronary ostial avulsion and inferior STEMI. She underwent supracoronary interposition graft replacement of the ascending aorta and hemiarch, interposition graft replacement of the innominate trunk and saphenous vein bypass grafting of the right coronary artery successfully. Innominate truncal rupture following aortic dissection is practically unknown and has not been described before in the absence of aortic rupture. Innominate truncal rupture secondary to other pathologies presents with supraaortic and mediastinal hematomas, but almost never with right hemothorax. On the backdrop of this unusual presentation with no neurological injury, we review the literature for innominate truncal dissection and rupture, other etiologies for innominate truncal rupture, the complex interplay of factors determining neurological injury and discuss the changes in the strategies and conduct of arterial return during cardiopulmonary bypass and selective antegrade perfusion imposed by this previously undescribed instance of innominate truncal rupture due to dissection.

As a result of improvements in early outcomes, long-term neurologicalal outcomes are becoming a major issue in pediatric cardiac surgery. The mechanisms of brain injury are numerous, but a vast majority of injuries are impervious to therapy and only a few are modifiable. The quality of perfusion during cardiac surgery is a modifiable factor and cerebral monitoring during bypass is the way to assess the quality of intra-operative cerebral perfusion. Near infrared spectroscopy (NIRS), as a diagnostic tool, has gained in popularity within the perfusion community. However, NIRS is becoming the standard of care before its scientific validation. This manuscript relates four clinical cases, demonstrating the limitations of NIRS monitoring during pediatric cardiac surgery as well as uncertainties about the interpretation of the recorded values.

The clinical relevance of cerebral oxymetry is needed before the use of NIRS as a decision making tool. Multimodal brain monitoring with NIRS, trans-cranial Doppler and electroencephalogram are currently under way in several pediatric centers. The benefit of this time-consuming and expensive monitoring system has yet to be demonstrated.

Post-cardiac catheterization femoral artery hemostasis can be accomplished with several mechanisms, including the FemoSeal® hemostasis device which has been designed and approved for closure of 6 French (F) arterial puncture sites. The aim of this study was to investigate whether the FemoSeal® vascular closure device can effectively and safely seal 7F arterial puncture sites after diagnostic and interventional cardiac catheterizations.

Femoral artery puncture sites of 50 consecutive patients undergoing cardiac catheterization were closed with the FemoSeal® vascular closure device, according to the manufacturer’s instructions. Efficacy endpoints were time to hemostasis and successful ambulation. Safety endpoints included bleeding complications, vessel occlusion and pseudoaneurysms.

Mean time to hemostasis was 57.8±26.3 seconds (0-125 seconds). Hemostasis was achieved in 100 percent of the 50 patients. One patient suffered minor bleeding the next day, i.e. local hematoma.

This clinical study demonstrates that the FemoSeal® vascular closure device, initially approved for closure of 6F arterial puncture sites, shows promising efficacy and safety to seal a larger (7F) femoral arterial puncture sites after diagnostic and interventional cardiac catheterizations.