Rosen

Simulation Case Library: The Case of the
Coiled Cardiac Catheter
Kathleen R. Rosen, MD*; Elizabeth H. Sinz, MD**
West Virginia University, Health Sciences Center, Morgantown, WV Original Article
Abstract
Many medical disciplines participate in the acute care ofhemodynamically unstable patients. At WVU we have manyopportunities for multidisciplinary critical care group instruction inour simulation facility. The main educational goals of this session arethe recognition and management of a pulmonary artery catheter thatis coiled in the right ventricle. Recognition of waveforms andidentification of catheter malposition are a priority in our critical careeducation programs. We present the scenario using the METI model Cmanikin with system 5.5 software. The target audiences for thisscenario at WVU include junior house staff from assorted disciplines, masters level physician assistant students, and medical students during the second and fourth years of training. This scenario has also beenincluded in a critical care medicine CME course for a variety of health care practitioners. We present a variety of the manufacturer’s pre-packaged hemodynamic instability scenarios. Standard man awake or relaxed with the hypotension-hemorrhage scenario isdescribed in detail. The focus is on catheter misplacement rather thanon disease state. Despite prior preparation from lecture with slides, textbook review, ordemonstration without patient context, most students do not recognize a right ventricular waveform when it is simulated in the context of a patient care scenario. Debriefing occurs immediately in the simulation laboratory and includes a review of typical waveform and pressure transitions as the catheter passes fromthe introducer to the wedge position. Measurement of cardiac output isdemonstrated. A variety of electronic resources are suggested for further self-study and more complete review of invasive monitoring principles and techniques. Students over the past 4 years have had an overwhelmingly positive response to this simulation experience. Background
Controversy about the use of pulmonary artery (PA) catheterization is multidisciplinary andinternational. Some groups have argued that the risks far exceed the benefits. 1 Catheter relatedcomplications are serious and potentially lethal. Misinterpretation of data and irrational therapymay independently produce morbidity or death. Many case reports appeared in the past decadedescribing morbidity and mortality related to pulmonary artery catheter (PAC) placement. Twocase reports describing new, unusual, & serious intra-operative complications appeared recently.
2,3 The principle criticisms of this technology are cost, complications, and absence of proof ofbenefit to the patient. Proponents of this technology offer guidelines and educational programs toinsure maximal safety. 4,5 Conversely, management of many high-risk patients can be facilitated.
A new evidence-based report synthetizes the results of 21 different randomized controlledstudies of PAC use in the ICU and strongly advocates PAC use before the onset of end organfailure to optimize oxygen delivery. 6 Educational Objectives
1. To recognize the characteristic PAC waveform associated with the right ventricle (RV).
2. To review waveform sequences visualized during PAC insertion3. To compare the quantitative and qualitative changes that occur in the PAC trace passing from 4. To identify the measured PAC insertion depth.
5. To associate the appearance of arrhythmias with potential PAC malposition.
6. To discriminate between normal and abnormal PAC pressures.
7. To discuss the correct procedure for repositioning an errant PAC.
Technical Description
The METI (METI, give city, state) model C full-scale manikin was used for this case. A patientmonitor capable of measuring cardiac output and displaying multiple (>3) simultaneous invasivepressure traces is essential. Resuscitation drugs and basic airway equipment are available. ThePAC is fixed at an insertion depth of 70 cm in our METI manikin. The syringe attached to thecatheter hub does result in a wedge trace when the balloon is inflated when the ”PA” is selectedfor catheter position. If one wishes to illustrate a different catheter depth with this type ofmanikin, a separate non-integral PAC may be positioned and dressed at either the subclavian orinternal jugular position. In this exercise the PAC will not wedge in response to balloon inflationbecause the “RV” is selected for catheter position.
We have run a variety of different shock scenarios to illustrate catheter misplacement. We haveused the patients and scenarios provided by METI or have programmed our own. The diseasestate is not part of the learning objectives. It is simply a backdrop for learning about the invasivemonitoring equipment. The pneumothorax, cardiac tamponade and anaphylaxis scenariosdecompensate too quickly. Because rapid intervention is needed for manikin survival in thesescenarios, they are not appropriate for an exercise where students must have sufficient time tofocus on diagnosis and treatment. Any scenario that transitions automatically as a function oftime would have the same limitation. Therefore we select a scenario that allows a beneficial learning experience for the group even if the diagnosis of right ventricular catheter positionoccurs rapidly. The preprogrammed scenarios that we found most useful are hemorrhage,anaphylaxis, sepsis, and congestive heart failure. These scenarios are overlaid on the “standardman awake” or “standard man relaxed” patient.
Target Audience
The critical care environment is a prototype for a multidisciplinary team centered approach topatient care. At WVU, we educate a variety of health care personnel, residents, medical studentsand physician assistants, to perform in this environment. The resident teams include traineesfrom anesthesia, surgery, surgical subspecialties, emergency medicine and internal medicine.
The physician assistants are pursuing masters degrees in either surgery or emergency medicine.
The medical students have participated during their 2nd and 4th years. The station is designed toresemble an ICU bay. A clinical monitor with color display and manikin reclining in a patientbed are the only equipment initially present. Students may request drugs and airway equipmentfor patient management.
This simulation experience has been an integral part of several on-going or repeated coursesincluding the medical student introduction to clinical skills, medical student fourth year requiredrotation in anesthesiology and Fundamentals of Critical Care Support (FCCS) for the past 3years. 7 The only groups for whom this exercise has been too simplistic (i.e. who rapidly andaccurately identified PA catheter malposition) are CA2-3 anesthesia residents with moderateexposure to intensive cardiovascular management and experienced ICU nurses. The format thatwe have employed is small group teaching with 6-8 students/group.
Simulation Script (general)
We allow approximately 30 minutes for completion of this simulation exercise. The scenario isterminated after 20 minutes and debriefing begins. The past medical history given is relevant tothe pathophysiology selected. The participants are informed that the ICU nurse has requested thatthey re-evaluate the patient following ICU admission. She is concerned about a low mean PAP.
They are also told that neither the systemic arterial pressures nor the systolic PA pressure havechanged. The low mean PAP is actually the result of RV positioning with the accompanyingdecrease in diastolic pressure. Arterial pressure, central venous pressure and PAC traces aredisplayed. “Right ventricle” is selected for the PAC placement. The monitor scales are initiallyset at 40 for the CVP and PA catheters and 200 for the arterial catheter. The students have theoption to change the display scale at any time.
Transducers are not part of the manikin’s invasive monitoring hardware. We do not emulate theclinical transducer system for this scenario. Transducer function and error are not in the learningobjectives for this elementary exercise. There is minimal drift in our Marquette Solar 8000monitor and METI manikin. Pressures are zeroed before the start of each simulation. Thestudents may ask to check a zero for any of the pressure traces displayed during the simulation.
Most groups do not recognize or comment upon the bizarre waveform. They focus upon medicaldiagnosis and treatment. If no mention of catheter position is noted for 5 minutes, then thecardiac rhythm changes to include 25% premature ventricular contractions (PVC’s). If anadditional 5 minutes passes without comment, then short, 10 second, runs of ventriculartachycardia are introduced at a frequency of 1 segment/minute.
Some participants have asked for a diagnostic chest x-ray during the simulation exercise. Weemploy a realistic 5-10 minute time delay between the request for x-ray services and the actualarrival of equipment and personnel. The scenario continues to progress during this time. Thereare 2 potential options if an x-ray is ordered very early in the scenario. During initial positioningof the patient for the diagnostic x-ray procedure, the scenario could progress very rapidly to theintroduction of runs of ventricular tachycardia. A second option is to have an x-ray of a coiledRV catheter available to display.
If clinical accuracy of the hemodynamic data is important to your teaching session, it isimportant to check these values well in advance of the session. Werecognized incorrect METI-generated data for cardiac output and systemic vascular resistance during sepsis. The cardiacoutputs are lower than expected and the SVR values are relatively normal. The 62 year oldsimulated patient with atrial fibrillation displays a cardiac output measurement > 6.5 l/min withnormal systemic and PA pressures.
Simulation Script (specific example)
We prefer to keep the exercise relatively simple from a programming perspective. We selecteither “standard man awake” or “standard man relaxed”. We overlay the hypotension-hemorrhage scenario. This scenario allows the loss of intravascular volume in 500 ml incrementsfrom 500-3000 ml total volume. We initially select either “-500” or “-1000ml”. We haveincluded graphics (tables 1 & 2) to demonstrate the cardiovascular changes that occur with thiscombination of patient simulation scenarios. The exact numbers may not be seen using othermonitors or different ambient temperatures but the relative changes are more important. Averagedata are listed for each volume state. The data were recorded while the manikin was breathing.
Respiratory variations were noted to exert a greater effect if the volume selected was > 1500 ml.
Measured cardiovascular pressures stabilized within 15 seconds of the selection of a volumestate. A significant delay, 2 minutes for spontaneous respiration and 2.25 minutes for positivepressure ventilation, was noted in the effect on cardiac output and systemic vascular resistance.
If “standard man relaxed” is selected, an endotracheal tube is in proper position and the manikinis receiving positive pressure ventilation. Our initial mandatory ventilation settings are tidalvolume = 600 ml, FIO2 = 0.4%, RR = 10, I:E = 1:2, PIP = 24/2 mm Hg. Initial respiratorymonitoring shows ETCO2 = 35 and SAO2 = 100%. The exhaled carbon dioxide does decreaseduring the exercise as progressive loss of intravascular volume leads to a decrease in cardiacoutput.
Simulation Case Stem
Bob is a 26 year old man with a longstanding history of Crohn’s disease who underwentemergency repair of a bowel perforation 12 hours previously. His pre-surgery medications wereprednisone 40 mg qd and fexofenadine . He was febrile, hypotensive, and dehydrated at time ofinitial presentation. Invasive monitoring, arterial line and PAC were inserted during surgery tofacilitate anesthetic and hemodynamic management. Blood loss was recorded as 500 ml duringthe procedure. He received 2500 ml of balanced salt replacement fluid. The patient wasextubated in the OR (or not) and has been drowsy but arousable in the ICU.
Behavioral Performance Expectations
The participants are expected to• identify the abnormal location of the PAC• verbalize the required steps to reposition the catheter - ascertaining that the PAC balloon is deflated- maintaining the sterile sheath over the catheter- gently withdrawing the catheter to a depth of 20 cm.
- inflation of the balloon and advancement of the catheter with attention to waveform, This can be also demonstrated at a station separate from the manikin but within view of thepatient monitor utilizing a PAC and introducer sheath inserted into a blind pocket.
Debriefing
The correct technique of PAC insertion is reviewed with emphasis on normal pressures,waveforms and average insertion depth. Differentiation of the RV from the PA traces ishighlighted. Participants are asked to note the rounded symmetric waveform of the RV change tothe more gradual descent characteristic of the pulmonary and other peripheral arteries. Minimalor no change in the systolic pressure is seen but there is a dramatic step-up in right sided diastolicpressure after crossing the pulmonary valve. The third characteristic change, i.e. the appearanceof a dicrotic notch in the PA tracing, is not noticeable with the current METI technology.
Potential acute complications are discussed. Deflation of the balloon after achieving satisfactoryposition in the pulmonary artery is the final step.
For further self-study, participants are referred to 2 educational web sites. Manbit is anAustralian site that offers both software and hardware pulmonary artery catheter simulators. 8Their extensive hypertext study guide is available on-line. It includes more than 300 references.
The pulmonary artery catheter education project (PACEP) is a comprehensive self-instructionprogram. 5 It is a collaborative project sponsored by seven different distinguished organizations.
When completed, four different levels of instruction will be available. Currently level 1 is on-linewith learning objectives. It contains 6 lessons on PAC topics. The concepts covered by these lessons are physiology, interpretation of hemodynamic data, therapeutic interventions, waveformanalysis, technical aspects and complications. Each lesson contains an introduction, slide show,pre-test, post-test, and slide gallery. Many sections also include mini case studies that enhanceadult learning through the addition of clinical context and problem solving. A short currentreview of the development and progress of this collaborative education project is available. 9 Validity
This simulation exercise has been demonstrated as a workshop for the International Meeting onMedical Simulation, January 2000 (authors, give location). Using the same equipment and METIscenarios described above, an international group of 15-18 anesthesiology faculty promptlyrecognized the catheter malposition and verbalized the correct steps to correct the problem.
Course evaluation forms for the FCCS sessions have been routinely distributed to the WVUcourse participants. They are asked to specifically rate the simulation experience and thesimulation instructors on a 5 point scale. Excellent was the descriptor for a score of 5 and goodfor a score of 4. Average, fair, and poor were 3, 2, and 1. During the most recent 2002presentation, the course and instructor received an average score of 4.2 and 4.3 respectively.
Only one rating of average and a single rating of fair were noted for each category out of a totalof 16 evaluations. The scores for this FCCS session are representative of previous courses.
Don’t be fooled by the apparent simplicity of this simulation exercise. We had initiallyintroduced the catheter misplacement as part of a larger shock/critical care scenario. In the first 6months, no one recognized this clinical dilemma. We realized that PA catheter malpositionneeded a scenario of its own. All of the groups to experience this scenario had received lectures,learning objectives and a textbook on this topic prior to the simulation. Over half of the studentshad had a demonstration of the typical waveform changes utilizing the same equipment withinthe previous 48 hours. Despite this classic preparation, very few students (1-2%) recognized theright ventricular trace in a clinical context. Approximately 100-150 students participate in thesesessions each year. Only 5 students have commented on the waveform during the past 3 years.
Pulmonary artery catheters have many potential complications. Acute complications areassociated with central venous access and PAC floatation. Long-term problems include infection,thrombosis, arrhythmias, cardiovascular rupture, catheter entrapment, pulmonary infarction, andiatrogenic. The misinterpretation of PAC data is not uncommon or benign. The abundantliterature sources citing PAC complications reflect the international nature of this crisis.
Morbidity, mortality and misuse of PAC were the basis for a proposal to withdraw approval andlimit usage of this technology only a decade ago. 1 Intensive efforts have begun to improve PACsafety through development of policy statements and education programs 4,5 and evidence-basedreview of PAC utilization. 6 In our program, traditional instruction didn’t translate to recognitionand appropriate action in the context of crisis simulation. We have not yet studied the impact ofthese simulation sessions on learning and retention. However, it is suggested that three session attributes, namely repetition, clinical context, and use of multi-modal sensory input, are key toimproving learning outcomes.
Table 1: Cardiovascular values as a function of hemorrhage for “standard man awake”
Scenario state
PAP s/d (m)
RV s/d (m)
Table 2: Cardiovascular values as a function of hemorrhage for “standard man relaxed”
Scenario state
PAP s/d (m)
RV s/d (m)
Acknowledgments
We would like to thank the Center for Rural Emergency Medicine for their help and support incoordinating the Fundamentals of Critical Care Support courses. We would also like toacknowledge the contribution of Lee Smith, MD to the simulation teaching sessions.
References
1. Connors AF Jr, Speroff T, Dawson NV, et al. The effectiveness of right heart catheterization in the initial care of critically ill patients. JAMA. 1996;276:889-97.
2. Huang GS, Wang HJ, Chen CH, et al. Pulmonary artery rupture after attempted removal of a pulmonary artery catheter. Anesth Analg. 2002;95:299-301.
3. Manecke GR Jr, Brown JC, Landau AA, et al. An unusual case of pulmonary artery catheter malfunction. Anesth Analg. 2002;95:302-4.
4. Practice guidelines for pulmonary artery catheterization. A report by the American Society of Anesthesiologists Task Force on Pulmonary Artery Catheterization. Anesthesiology. 1993;78:380-94.
5. Pulmonary artery catheter education project (PACEP). Avaialable at: http://www.pacep.org.
6. Kern JW, Shoemaker WC. Meta-analysis of hemodynamic optimization in high-risk patients. Crit 7. Society of Critical Care Medicine. Fundamental critical care support course. Available at: http://www.sccm.org/edu/fccscourses.html.
8. MANBIT Technology. Pulmonary arterial catheterisation simulator (PAC simulator). Available 9. Montgomery WH, Hanson III CW. Pulmonary Artery Catheter Education Program: a progress report on this new collaborative educational tool. Am Soc of Anesthesiol Newsletter. 2002;66(8):7-9.
Available at: http://www.asahq.org/NEWSLETTERS/2002/8_02/pulmonary.htm

Source: http://jepm.seahq.net/archiveVolumes/2001-02/rosen.pdf