ImaCor White Paper: Clinical and Economic Benefits of ImaCor TEE Monitoring 2010-03*

8/22/2019 ImaCor White Paper: Clinical and Economic Benefits of ImaCor TEE Monitoring 2010-03*

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Clinical and Economic Benefits of ImaCor TEE Monitoring

White Paper 2010-03*Harold M. Hastings, Ph.D.

Scott L. Roth, M.D.

Executive summaryTEE monitoring in cardiac and general ICU populations with the ImaCor TEE monitoring system

led to significant changes in hemodynamic management in over half of the patients studied, witheconomic benefits significantly exceeding the cost of probes used.

1. Cardiac surgery. In a series of 46 patients at two institutions, surgical re-exploration wasavoided in five patients (11%), reducing hospital charges by $ 150,000 (extrapolated from Speir, 2009),and fluid and pressor administration was changed in 23 patients (50%), reducing hospital charges by atleast $414,000 (based on literature review below, especially Hravnak et al., 2010), for a total reduction of

at least $564,000. Cost of 49 ImaCorClariTEE probes (some patients used more than one probe):$49,000. Not included: economic benefits of TEE detection of tamponade and rapid surgicalintervention, TEE-guided VAD adjustment, likely reduction in acute kidney injury (AKI, a common,major and expensive complication of cardiac surgery) due to reduced pressor usage. In conclusion, grosssavings of at least $564,000 were 11 times the cost of probes; on a per patient basis gross savingsaveraged at least $12,260; twelve times the cost of a probe.

2. Non-cardiac ICU. In a series of 68 patients, hemodynamic management was changed in 28(41%), reducing hospital charges by at least $504,000. Cost of 68 probes: $68,000. Not included: likelyreduction in AKI due to reduced pressor usage. In conclusion, gross savings of at least $504,000 wereover seven times the cost of probes; on a per patient basis gross savings averaged at least $6,400; againover seven times the cost of a probe.

Conclusions. As described above, studies to date have shown significant clinical and economic

impact by demonstrating the potential to reduce cardiac surgery costs by at least $12,000 per patient andgeneral ICU costs by at least $6,400 per patient in study populations.

Figure 1. Economic Impact of ImaCor TEE monitoring in the cardiac ICU and general ICU, perpatient. Savings from avoided re-explorations are shown in red; savings from hemodynamic managementare shown in plum. Savings far exceed the $1,000 cost of the ImaCor ClariTEE probe.

Avoiding re-op:$3,260

Probecost

Preventing and treating shock: $9,000


ImaCor saves $11,260 per pt. in the CARDIAC ICU: from a 46 patient study*

11 the cost of a probe

ImaCor saves $6,410 per pt. GENERAL ICU: from a 68 patient study**

6.4 the cost of a probe

0 $2000 $4000 $6000 $8000 $10,000 $12,000

*see FACTS-Care 2010 abstract **see SCCM 2010 abstract


Probecost







0 $2000 $4000 $6000 $8000 $10,000 $12,000


* Notes on ImaCor White Papers follow on page 2.


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Notes on ImaCor White Papers.The purpose of ImaCor White papers is to provide background for understanding the role of the ImaCor

TEE system in addressing major areas of clinical concern.ImaCor White Paper 2009-01 addressed Hemodynamic Monitoring.ImaCor White Paper 2009-02 addressed ImaCor TEE for Sepsis MonitoringImaCor White Paper 2010-01 addressed the role of ImaCor TEE in avoiding and guiding re-exploration

post cardiac surgery.

ImaCor White Paper 2010-02 is an updated version of White Paper 2009-02, addressing ImaCor TEE forSepsis Monitoring.

White Papers and Case Studies are available upon request: please email [email protected].

Outline.We describe the clinical and especially economic impact of hemodynamic monitoring with the

ImaCor TEE monitoring system in cardiac ICU and general ICU populations. In particular, ImaCor TEEmonitoring is shown to save an average of over $12,000 per patient, twelve times the cost of a probe, incardiac ICU patients; over $ 6,400 per patient, 6.4 times the cost of a probe in general ICU patients.

This paper is organized as follows:1. Background

a. Tissue and organ perfusionthe challenge in critical careb. Detecting hemodynamic instability: From TEE hemodynamic assessment to TEE

hemodynamic monitoringc. Complications and cost of hemodynamic instability

2. Cardiac ICU case series3. General ICU case series4. ConclusionsAppendices

1. Illustrative cases2. Supporting economic data

References

1. Backgrounda. Tissue and organ perfusionthe challenge in critical care

One major challenge in critical care is providing and maintaining adequate tissue and organperfusion. Hemodynamic stability is one key component of tissue and organ perfusion. The central roleof hemodynamic stability in maintaining adequate tissue and organ perfusion has led to a wide variety ofclinical interventions (fluids, pressors, inotropes, etc.), clinical protocols and hemodynamic monitors.

On the other hand, organ failure may have many causes, as illustrated by acute kidney injury(AKI), a common and expensive complication of cardiac surgery (Hein, 2006a,b,c; Rosner and Okusa,2006; Rosner, Portilla and Okusa, 2008; Elahi et al., 2009; STS risk calculator). In particular, Rosner and

Okusa (2006) cite systemic inflammation, reduced LV function, vasoactive agents, and hemodynamicinstability [in general] as postoperative pathophysiological factors in AKI.

b. Detecting hemodynamic instability: Development of the ImaCor TEE hemodynamic monitoringsystem

In order to better understand the clinical and economic impact of the ImaCor TEE hemodynamicmonitoring system, we begin with a brief review of the unique advantages of TEE for hemodynamicassessment. Trans-esophageal echocardiography (TEE) has long been accepted as the gold standard in thecardiac operating room because TEE allows direct visualization of cardiac filling and function, and has


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the unique ability to identify specific causes of hemodynamic instability. These advantages have ledVieillard-Baron et al. (2003, 2006), and Poelaert and Schpfer (2005) to call for more widespread use ofTEE for hemodynamic assessment in intensive care. Dr. Frances Colreavy eloquently expressed thepotential of TEE in a post-graduate lecture at the 2010 Barcelona meeting of the European Society forIntensive Care Medicine in an acronym for rapid echocardiographic assessment of hemodynamicproblems:

V: ventricles (left and right ventricles)O: obstructionsT: tamponade (see ImaCor case cited below)E: effusion (see ImaCor case cited below)D: dissection

It is especially important to properly assess fluid responsiveness to properly guide hemodynamicstabilization. For example, Gordon and Russell (2005) observed that the treatment group in a variety ofgoal-directed therapies consistently received more fluid early than controls, and this may be the reasonfor their success. Indirect methods for assessing fluid responsiveness such as the PA catheter rely onassumed pressure-volume relations, and are thus limited at best (Marik, Baram and Vahid, 2008); incontrast, TEE can be used to directly assess fluid responsiveness (Charron et al., 2006).

c. Complications and cost of hemodynamic instabilityMajor complications of hemodynamic instability following cardiac surgery include (1) surgical

re-exploration, (2) increased resource utilization and length of stay, and (3) AKI, among others. Thelatter two factors, increased resource utilization and length of stay, and AKI are also major complicationsin general ICU patients. This section presents detailed analyses behind our cost data for re-exploration($30,000 can be saved by avoiding one re-exploration) and hemodynamic instability ($18,000 per patientcan be saved by improving hemodynamic management). There are several large studies, mostly focusingon complication rates, length of stay and other clinical impact.

Hein et al. (2006 a, b, c) reported complication rates and length of stay data on all cardiacsurgery patients [2,683 patients] admitted postoperatively to the cardiothoracic ICU at the HospitalCharit-University Medicine Berlin, for a period of two years from August 1, 2001 to August 31, 2003.

The STS-CAPS Care study reported complication rates on 2,390 high risk CABG patients.Hravnak et al. (2010 presentation) reported hemodynamic instability and hospital charge data on

622 patients in a step down unit.These data, cost data from Speir (2009) and data from several smaller studies yield consistent

estimates of the likelihood and costs associated with three main complications of hemodynamicinstability: (1) surgical re-exploration, (2) increased resource utilization and length of stay, and (3) AKI.The main results are summarized below; details are presented in appendix 1.

(1) Surgical re-explorationLikelihood: Surgical re-exploration may occur in 7-12% of typical patients. Hein et al.

(2006 a, b, c) cited re-exploration in 7.2% of all cardiac surgery patients [2,683 patients]admitted postoperatively to the cardiothoracic ICU at the Hospital Charit-University MedicineBerlin, for a period of two years from August 1, 2001 to August 31, 2003. 78.2 % of patients

with re-exploration had an ICU stay > 3 days; compared with 19.2 % of patients with no re-exploration. Even though CABG has become relatively routine, Ranucci et al. (2008) cite a re-exploration rate of 2-6%, with re-exploration resulting in much higher mortality: 14.2% versus3.4%. For comparison, the STS CAPS-Care study of 2,390 high risk CABG patients (reported byJ Williams at FACTS-Care 2010) cites a re-exploration rate of 9-10%. In fact, we have seen asignificant increase in operative risk in CABG because Patients are sicker today (Biancari et al.,2009). We found a risk of 12.1% for MVR+CABG in a patient with a few other risk factorsusing the STS calculator available on the web.

Cost: $ 30,000 in 2010 based upon Speir (2009).


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(2) Hemodynamic instability (in general).Likelihood: Hravnak et al. reported on a large (622 patient) inclusive study at the 23rd

ESICM Annual Congress in Barcelona, October 2010: 34% of patients in a step-down unitdisplayed at least some mild hemodynamic instability, 18% at least some major hemodynamicinstability. Hemodynamic instability may be much more common in the ICU, especiallyfollowing cardiac or serious general surgery.

Cost: Our analysis of Hravnaks data found that the presence of any hemodynamicinstability increased length of stay by at least 1.3 days, and hospital charges by at least $18,000per patient; see Appendix 2. These data are consistent with an example from sepsis protocols:Trzeciak et al. (2006) found that the use of sepsis protocols reduced median hospital facilitycharges $53,000 per patient. Shorr et al. (2007) found that LOS was reduced by five days.When all costs of a prolonged LOS were included, 1 day LOS corresponded to $ 11,000 in costthroughout the stay in 2007.

We shall make a conservative estimate that an increased length of stay by one day due tohemodynamic instability costs at least $18,000.

Note on vasoactive agents. The use of vasoactive agents was also associated with longer

LOS (Hein, 2006 a, b, c): 46.0 % of patients receiving Dopamine/dobutamine > 5 g kg1 min1

had an ICU stay > 3 days; compared with 25.3 % of patients receiving Dopamine/dobutamine 5

g kg

1

min

1

.

(3) Acute kidney injury.Likelihood. The announcement of an upcoming SCCM clinical focus session (SCCM

Clinical Focus 2011, http://www.sccm.org/Conferences/Topics/Clinical-Focus-Renal/Pages/default.aspx) cites that AKI occurs in approximately 67% of intensive care unit(ICU) patients annually and is associated with increased hospital mortality rates.

Generally defined as an abrupt and sustained decrease in kidney function, treatment ofAKI is complex. Rosner, Portilla and Okusa (2008) reported that Acute renal failure (ARF)occurs in up to 30% of patients who undergo cardiac surgery, with dialysis being required inapproximately 1% of all patients. The development of ARF is associated with substantialmorbidity and mortality independent of all other factors. Heins (2006 a, b, c) large study

reported a rate of renal failure involving dialysis of 9.5%; the recent STS CAPS-Care study(reported at FACTS-Care, Washington, DC, October 2010) reported a rate of 2-4% in high riskCABG patients. The STS calculator projected AKI in 7.7% of patients receiving MVR andCABG with a few other risk factors. Shaw et al. (2008) and Elahi et al. (2009) report a rate of5%. Hein (2006 a, b, c) showed that AKI with dialysis (Called ARF-D in Heins work) is asignificant risk factor for prolonged length of stay: odds ratio 6.83. 86.2 % of patients with ARF-D had an ICU stay > 3 days; compared with 19.2 % of patients with no ARF-D.

Cost. $ 60,000, extrapolated from Speir (2009).

We now apply the above economic analysis to two case series of patients monitored by theImaCor hemodynamic monitoring system: (i) 46 cardiac surgery patients at UAB and Vanderbilt, and(ii) 68 other ICU patients at eight institutions.

2. Cardiac surgery case series.

In a series of 46 patients at two institutions, surgical re-exploration was avoided in five patients(11%), reducing hospital charges by $ 150,000 (extrapolated from Speir, 2009), and fluid and pressoradministration was changed in 23 patients (50%), reducing hospital charges by at least $414,000 (basedon literature review below, especially Hravnak et al., 2010), for a total reduction of at least $564,000.Cost of 49 ImaCor ClariTEE probes (some patients used more than one probe): $49,000.

We have not included economic benefits of TEE detection of tamponade and rapid surgicalintervention, TEE-guided VAD adjustment, likely reduction in AKI, (a common, major and expensivecomplication of cardiac surgery) due to reduced pressor usage, all due to insufficient specific data.


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In conclusion, gross savings of at least $564,000 were 11 times the cost of probes; on a perpatient basis gross savings averaged at least $12,260; twelve times the cost of a probe.

We conclude that the ImaCor TEE system offers significant economic benefits in post cardiacsurgery patients. Some of these results were presented at the cardio-thoracic surgery conference FACTS-Care, Washington DC, October 2010.

3. General ICU case series.In a series of 68 patients, hemodynamic management was changed in 28 (41%), reducing hospitalcharges by at least $504,000. Cost of 68 probes: $68,000. We have not included likely reduction in AKIdue to reduced pressor usage. In conclusion, gross savings of at least $504,000 were over seven times thecost of probes; on a per patient basis gross savings averaged at least $6,400; again over seven times thecost of a probe.

We conclude that the ImaCor TEE system offers significant economic benefits in post cardiacsurgery patients. Some of these results were presented at the critical care conference SCCM, Miami, FL,January 2010. We also reported there that the overall impact of the ImaCor Zura imaging system with theminiaturized ClariTEE probe was equivalent to the impact reported by Httemann's (2006) large reviewof studies with conventional TEE probes. The ImaCor system influenced clinical management in 40% ofpatients; this compared well with Httemann's reported 36% (range 10% - 69%). We conclude thatmonitoring cardiac function via direct visualization with a miniaturized TEE probe has significant clinicalutility.

Figure 2. Clinical impact of the ImaCor TEE system in an early study (Hastings et al., SCCM 2010presentation)

4. Conclusions.As described in our application for a Qualifying Therapeutic Discovery Project grant, ImaCor

developed a TEE monitoring system to improve critical care and peri-operative management bydiagnosing a common problem, hemodynamic instability, and its underlying causes moved TEE, the goldstandard for diagnosing and monitoring cardiac filling and function, key determinants of hemodynamicinstability out of the operating room, and beyond on-demand assessment to an episodic monitoring tool,using a miniaturized (5.5 vs. 10-14 mm) probe. ImaCor TEE monitoring allows intensivists to diagnoseunderlying causes of hemodynamic instability through ongoing direct visualization, and thus guidetherapeutic management. The QTDP program funded projects with a significant potential for reducinghealth care costs, and ImaCor was pleased to have received the endorsement of QTDP support.

Clinical impact of the ImaCor system

0

10

20

30

40

50

Patient

population

New information Influenced

mamagement

Numberofpatients


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As described above, studies to date have shown significant clinical and economic impact bydemonstrating the potential to reduce cardiac surgery costs by over $7,200 per patient and general ICUcosts by $3,100 per patient in study populations.

Figure 3. Economic Impact of ImaCor TEE monitoring in the cardiac ICU and generalICU, per patient. Savings from avoided re-explorations are shown in red; savings from

hemodynamic management are shown in plum. Savings far exceed the $1,000 cost of the ImaCorClariTEE probe.


Probecost







0 $2000 $4000 $6000 $8000 $10,000 $12,000



Probecost







0 $2000 $4000 $6000 $8000 $10,000 $12,000



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Appendix 1. Illustrative cases.Here are four cases and one additional case series which illustrate the role of the ImaCor system

in TEE monitoring.

Case 1. Hemodynamics fluids can be trickyAssessing volume status with the ImaCor TEE monitoring system. Hemodynamic instability in a 77

year-old, 48 kg female post spinal surgery was due to volume deficiency despite receiving 4.5 L of fluids.

Patient with Hypotension in PACU Following Spinal Fusion(http://www.imacormonitoring.com/case_deta.php?id=9 )Jesse Marymont, MD, Cardiac AnesthesiaEvanston Hospital, Evanston, IL

Background: A 77 year-old, 48 kg female with multiple myeloma presented with a collapsed T-12 vertebrae. On admission her hemoglobin was 9.7. Additional medical history included hypertension, aprior coronary angioplasty, and a prior carotid endarterectomy.

During the operation the patient sustained a blood loss of 1700 mL with a urine output of 400mL. During the procedure, the patient received 4500 mL of IV fluids, 4 units of PRBC, and 250 mLHespan. In the PACU the patient was still found to be hypotensive (70-80 mm Hg systolic) after 750 mLof IV fluid and neosynepherine were administered.

Methods: The attending physician ordered a bedside TEE using the ClariTEE probe. The probewas successfully placed, and the transgastric short-axis view (TGSAV) of the left ventricle (LV) wasobtained.

Qualitative and quantitative analysis of the left ventricular size and function revealedhypovolemia, ventricular hypertrophy, and abnormal wall motion. With this information, additional fluidswere aggressively administered and pressors were titrated and subsequently discontinued upon achievingnormotensive blood pressure. The ClariTEE probe remained indwelling in the patient to enable furtherassessments.

Results: Patient was normotensive (140 mm Hg) in the intensive care unit the next morning.Conclusions: Postoperative hemodynamic stability is a common complication following non-

cardiac surgery. Empiric administration of IV fluids and plasma expanders is inadequate and maycontribute to new problems. The ClariTEE probe is an effective tool for diagnosing causes ofhemodynamic instability in the PACU environment due to the immediacy of the imaging and theactionable data provided to the intensivists.

Case 2. Pressers are often needed, but can be dangerousTEE-guided rapid weaning from pressors. The following case illustrates the role of the ImaCor TEEmonitoring system in rapid weaning from pressors in a post cardiac surgery patient with an ischemic gut(SCCM 2011, Poster # 936).

TEE-guided rapid weaning from pressors in a post cardiac surgery patient with an ischemic gutJiri Horak, Hospital of the University of Pennsylvania, Philadelphia, PA

Frans van Wegenberg, University of Pennsylvania School of Medicine, Philadelphia, PAScott Roth, Harold Hastings, ImaCor Inc

A 37-year-old man with a history of hypertension initially presented with a ruptured type Adissection. He underwent aortic valve resuspension, total arch replacement, and replacement of theascending aorta. Echo on postop day 5 showed normal biventricular function.

The patient did well but complained of severe abdominal pain and increasing distress on day 7.Lab work revealed new onset coagulopathy, acute renal failure, hyperkalemia, increased white blood cellcount and rising lactate levels. The patient became progressively hypotensive requiring phenylephrine


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support at 150mg/min and ICU admission. Bedside transthoracic echo (TTE) showed normalbiventricular function. CT angiography revealed a flap compromising the superior mesenteric artery andceliac artery origins. Emergent thoracic endovascular aortic repair and exploratory laparotomy wereperformed. The patient required CPR following cardiac arrest in the OR. Exploratory laparotomy revealedonly dusky gall bladder and gut. The patient was left open.

The patient was hemodynamically unstable at high levels of pressor support. A ClariTEE probe

revealed adequate systolic function, leading the physician to conclude that diastolic dysfunction was thecause of hemodynamic instability. (Cardiac dysfunction after intestinal reperfusion has been described inrats, Horton and White, 1991). Pressors were rapidly weaned and fluid administered under TEEmonitoring.

Figure 4. Rapid Weaning from Pressors under TEE Monitoring. Pressors were rapidly weaned and fluidadministered under TEE monitoring. Hemodynamics remained stable throughout the process. At the endof the 7 hour process: Epinephrine was off, Phenylephrine was down 50% and Vasopressin was down50%.

We were able to confidently wean down pressors because TEE monitoring revealed satisfactorysystolic function throughout the process.

This was particularly important as excessive pressors in this patient could have caused further gutischemia, inflammatory mediator release, and further diastolic dysfunction. TEE monitoring in the ICUwith a miniaturized probe is a valuable addition for assessing cardiac function. Further studies to evaluate

its impact on efficacy and clinical outcomes are warranted.

Epinephrine

reduced from 2mcg/ min to 0

Phenylephrinereduced from200 to 100 mcg/min

Vasopressinreduced from0.08 to 0.04 unit/min


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Case 3. Surgical re-exploration: avoid it if you canUse of the ImaCor TEE monitoring system to avoid surgical re-exploration for hemodynamic instabilitypost cardiac surgery. Effusion, a common complication of cardiac surgery, was managed medically underthe guidance of the ImaCor TEE monitoring system.

TEE Monitoring Guides Medical Management of Cardiac Effusion

Benjamin H Webster, MDChad E Wagner, MDVanderbilt University Hospital, Nashville, TN

A 66-yr-old male with a history of two-vessel coronary artery bypass (CAB) and aortic valve(AV) stenosis with valve area of 0.8cm2 presented with exertional chest pain, shortness of breath, andlightheadedness. After evaluation by left and right heart catheterization the patient was scheduled forurgent re-do sternotomy, aortic valve replacement, and repeat coronary artery bypass (CAB) surgery.

After induction of anesthesia, intraoperative transesophageal echocardiography (TEE)examination revealed severe aortic stenosis, left ventricular hypertrophy, and normal wall motion with anEF of 50%. He underwent CAB x 2 with left internal mammary artery to left anterior descending artery,saphenous vein to first obtuse marginal, and AV replacement with a 25mm bioprosthetic valve.Dobutamine and norepinephrine infusions were required for separation from cardiopulmonary bypass(CPB) and initial TEE demonstrated a well placed bioprosthetic AV and absence of regional wall motionabnormalities (RWMA). Significant bleeding and hemodynamic instability required administration ofmultiple blood products, initiation of a vasopressin infusion, and recombinant factor VIIa. The patientwas stabilized and transported to the cardiovascular intensive care unit (CVICU).

Initial hemodynamic assessment in the CVICU showed a cardiac index (CI) of 1.5, arterial bloodpressure (ABP) 81/45, pulmonary artery catheter (PAC) pressure of 40/23, central venous pressure (CVP)of 14, systemic vascular resistance (SVR) of 898, mixed venous oxygen saturation (MVO2) of 46%, lowurine output, and mildly elevated chest tube output. Over the next hour the MVO2 remained low with anincreasing CVP (20mmHg) and decreasing urine output. A miniaturized disposable TEE monitoringprobe (ImaCor) was placed, which demonstrated a posterior and lateral pericardial effusion withinadequate left ventricular end diastolic area (LVEDA) despite high filling pressures (image 1/video1).Based on the TEE findings we continued volume resuscitation despite elevated measured PAC fillingpressures. LV volume increased despite a small increase in pericardial fluid and the patientshemodynamic status began to stabilize (image 2/video2).

The CVICU team and cardiac surgeon decided to continue to monitor the pericardial effusion andLV volume with the ImaCor TEE probe rather than returning to the operating room for re-exploration.Over the subsequent ten hours episodic assessment using the ImaCor probe demonstrated continuedresolution of the pericardial fluid collection with increased LVEDA (image 3). Hemodynamicsconcomitantly improved to: ABP 115/65, CI of 2.6, PAP 40/22, CVP 14, SVR 735, and MVO2 of 60%.Vasoactive infusions were able to be weaned and the patient was extubated and transferred tointermediate care.


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Case 4. Surgical re-explorationintervene rapidly under guidance, if you must.Detection of tamponade as the cause of hemodynamic instability with the ImaCor TEE monitoringsystem. When surgical re-exploration is necessary, rapid, guided re-exploration can reduce both mortalityand morbidity (c.f. Ranucci, 2008). This case also demonstrates the advantages of TEE over TTE indiagnosing the cause of hemodynamic instability.(http://www.imacormonitoring.com/case_deta.php?id=11 )

Tamponade Diagnosed Post CABGMichael Wall, MD, Cardiac AnesthesiaBarnes-Jewish Hospital, St. Louis, MO

Background: 86 year-old male with extensive medical history who had undergone elective CABGseveral hours earlier. In the CTICU, the patient was tachycardic and hypotensive (80110 mm Hg) whileon Levophed. SVO2 was 32% and CVP was 25 mm Hg.

TEE examinations: Attending ICU physician ordered a transthoracic echo (TTE) and atransesophageal echo (TEE) with the ClariTEE probe. Both studies were performed at the bedsidesimultaneously in the ICU.

Results: An echo technologist performed the TTE from the patients left side and was unable to

assess the right atrium. The attending ICU physician, performing the TEE exam from the right side of thebed easily placed the probe without complication and was quickly able to obtain a four-chamber view ofthe heart.

From this view, the physician noticed a large blood clot pressing on the right atrium andconcluded that localized tamponade was the cause of the patients deterioration. Based on this newinformation, the patient was taken directly back to the operating room for an immediate reoperation andthe clot was removed. The patients status immediately stabilized, and he returned to the ICU. Shortlyafter the patients return, the physician performed a second assessment with the ClariTEE probe anddetermined that the right atrium was filling normally. The patients blood pressure was no longer labile(140-150 mm Hg), Levophed was discontinued, and the patient was hemodynamically stable (HR: 70beats/minute and CVP: 8 mm Hg).

Discussion: The published incidence of tamponade following cardiac surgeries is 0.5%-5.8%

(Russo et al., 1993), and re-operation due to tamponade is costly and associated with increased mortalityand prolonged hospital stay. While the use of TEE is well documented as an effective tool in the cardiacO.R. for monitoring patients, there is currently no effective method of monitoring these patients outsidethe O.R. where serious complications often occurs. In this specific case, as often occurs in the ICU, theTTE was unable to provide the critical information required to make this diagnosis.Conclusion: The ClariTEE probe can be an effective and useful tool in diagnosing tamponade in post-cardiac surgery cases. Moreover, the ClariTEE probe allows physicians to establish a continuity of carein the ICU that heretofore has not been available.

Case series. Liver transplants. Dr. Luc Frenette (UAB) used the ImaCor system to monitor a caseseries of 23 consecutive liver transplant patients to date. Maintaining hemodynamic stability in thesepatients is especially challenging because of conflicting demands of transplant surgery and post-surgicalrecovery. Dr. Frenette found reduced pressor usage with expected significant economic benefits. Detailswill be reported elsewhere, later.


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Appendix 2. More detailed clinical and economic analysis.(1) Surgical re-exploration

Likelihood: Surgical re-exploration may occur in 7-12% of typical patients. Hein et al. (2006a,b,c) cited re-exploration in 7.2% of all cardiac surgery patients [2,683 patients] admittedpostoperatively to the cardiothoracic ICU at the Hospital Charit-University Medicine Berlin, for a periodof two years from August 1, 2001 to August 31, 2003. 78.2 % of patients with re-exploration had an

ICU stay > 3 days; compared with 19.2 % of patients with no re-exploration. Even though CABG hasbecome relatively routine, Ranucci et al. (2008) cite a re-exploration rate of 2-6%, with re-explorationresulting in much higher mortality: 14.2% versus 3.4%. For comparison, the STS CAPS-Care study of2,390 high risk CABG patients (reported by J Williams at FACTS-Care 2010) cites a re-exploration rateof 9-10%. In fact, we have seen a significant increase in operative risk in CABG because Patients aresicker today (Biancari et al., 2009). We found a risk of 12.1% for MVR+CABG in a patient with a fewother risk factors using the STS calculator available on the web.

Cost: $ 30,000 in 2010 based upon Speir (2009).Effects on length of stay: Re-exploration is associated with increased length of stay (Hein, 2006a, b, c).

Table 1. Re-exploration is associated with longer ICU stay.

Re-explor-ation

Patients with an ICUstay > 3 days

Patients with an ICU

stay 3 days

Totals

Yesre-exploration

151 42 193 (7.2 % of total2,683)

No 534 1,956 2,490 (92.8% of total2,683)

Totals 685 (26% of total2,683)

1,998 (74% of total2,683)

2,683 total patients

78.2 % of patients with re-exploration had an ICU stay > 3 days; compared with 19.2 % ofpatients with no re-exploration.

(2) Hemodynamic instability (in general).Likelihood: Hravnak et al. reported on a large (622 patient) inclusive study at the 23rd ESICM

Annual Congress in Barcelona, October 2010: 34% of patients in a step-down unit displayed at leastsome mild hemodynamic instability, 18% at least some major hemodynamic instability. Hemodynamicinstability may be much more common in the ICU, especially following cardiac or serious generalsurgery.

Cost: Our analysis of Hravnaks data found than the presence of any hemodynamic instabilityincreased length of stay by at least 1.3 days, and hospital charges by at least $18,000 per patient. Thesedata are consistent with an example from sepsis protocols: Trzeciak et al. (2006) found that the use ofsepsis protocols reduced median hospital facility charges $53,000 per patient. Shorr et al. (2007) foundthat LOS was reduced by five days. When all costs of a prolonged LOS were included, 1 day LOS

corresponded to $ 11,000 in cost throughout the stay in 2007.We shall make a conservative estimate that an increased length of stay by one day due tohemodynamic instability costs at least $10,000. Details follow.


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Table 2. Likelihood of hemodynamic instability (from Hravnak et al., 2010)

Type of hemodynamicinstability

Duration of

hemodynamicinstability mild majornone 66% 82%1-30 min 19% 9%

31-90 min 7% 5%>90 min 8% 4%

Table 3. Effects of mild hemodynamic instability upon length of stay (LOS) and hospitalcharges, analysis based on Hravnak et al. (2010).

Hospital chargesDuration ofhemodynamicinstability

Length ofstay

Total forstay

Dailyaverage

Increased due tohemodynamicinstability

none 4.6 days $104,500 $22,700 none1-30 min 5.9 days $122,500 $20,700 $18,00031-90 min 6.6 days $145,500 $22,000 $41,000>90 min 7.0 days $152,200 $21,800 $47,700

Figure 5. Increased costs due to hemodynamic instability reflect both increased resource use inearly days, and increased length of stay.

Length of stay (days)

Hemodynamics

stable

Increased use of resources totreat hemodynamic

instability increases cost

Chargeseachday($)

Increased

LOS due to

hemodynamic

instability also

increases cost

Note on vasoactive agents. The use of vasoactive agents was also associated with longer LOS

(Hein, 2006 a, b, c): 46.0 % of patients receiving Dopamine/dobutamine > 5 g kg1 min1 had an ICU stay

> 3 days; compared with 25.3 % of patients receiving Dopamine/dobutamine 5 g kg1 min1.


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Additional notes on protocolized fluid administration.Sepsis patients: the major difference between treatment and control groups was increased fluid

over the first 6 hours (Rivers, 2001): 5 L vs. 3.5 L. Mortality was sharply reduced. As stated above,Trzeciak et al. (2006) found that the use of sepsis protocols reduced median hospital facility charges$53,000 per patient. Shorr et al. (2007) found that LOS was reduced by five days.

Cardiac surgery patients: similarly, the treatment group received 3.2L of fluid in the first

postoperative night, ws. 2 L for controls (Plnen et al., 2000) and had a significantly shorter hospitalstay.General major surgery patients: Pearse et al. (2005) reported fewer complications after increased

early fluid administration (treatment group: 1.9 L vs. 1.2 L for controls).In summary, Gordon and Russell (2005) reported that the treatment group has consistently

received more fluid in prior studies and this may well be the major contributor to success.

Additional notes on vasoactive agents and length of stay. The use of vasoactive agents was alsoassociated with longer LOS (Hein, 2006 a, b, c): 46.0 % of patients receiving Dopamine/dobutamine > 5

g kg1 min1 had an ICU stay > 3 days; compared with 25.3 % of patients receiving

Dopamine/dobutamine 5 g kg1 min1.

Table 4. Dopamine/dobutamine administration is associated with prolonged stayCatecholamine therapy onadmission to the ICU

Patients with anICUstay > 3 days

Patients withan ICU

stay 3 days

Totals

None/dopamine/dobutamine

5 g kg1 min1

254 1,493 1,747

Dopamine/dobutamine > 5 g

kg1 min1

431 505 936 (34.9 % oftotal 2,683

Totals 685 (26% oftotal 2,683)

1,998 (74% oftotal 2,683)

2,683 totalpatients

46.0 % of patients receiving Dopamine/dobutamine > 5 g kg1 min1 had an ICU stay > 3 days;

compared with 25.3 % of patients receiving Dopamine/dobutamine 5 g kg1 min1

Conclusions. Hemodynamic stabilization brings significant clinical and economic benefits; thesebenefits are increased when patient status allows increases in fluid administration and decreases invasoactive agents. See, for example, Appendix 1, Case 1 and Case 4. Increased in fluid administrationand decreased vasoactive agents were common management changes when ImaCor TEE monitoring wasused. A detailed discussion will appear elsewhere.

(3) Acute kidney injury.Likelihood. Rosner, Portilla and Okusa (2008) reported that Acute renal failure (ARF) occurs in

up to 30% of patients who undergo cardiac surgery, with dialysis being required in approximately 1% ofall patients. The development of ARF is associated with substantial morbidity and mortality independentof all other factors. Heins (2006 a, b,c) large study reported a rate of renal failure involving dialysis of

9.5%; the recent STS CAPS-Care study (reported at FACTS-Care, Washington, DC, October 2010)reported a rate of 2-4% in high risk CABG patients. The STS calculator projected AKI in 7.7% ofpatients receiving MVR and CABG with a few other risk factors. Shaw et al. (2008) and Elahi et al.(2009) report a rate of 5%.

Cost. $ 60,000, extrapolated from Speir (2009).

Effects on length of stay. Hein (2006 a, b, c) showed that AKI with dialysis is a significant riskfactor for prolonged length of stay: odds ratio 6.83. Here is a summary of his data.


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Table 5. AKI (here called ARF) with dialysis is associated with longer ICU stay (univariateanalysis from Hein (2006 a, b, c).

ARF-D Patients with anICUstay > 3 days

Patients with an ICU

stay 3 days

Totals

Yes - ARF-D 219 35 254 (9.5 % of total

2,683)No 466 1,963 2,429 (90.5% of total2,683)

Totals 685 (26% of total2,683)

1,998 (74% of total2,683)

2,683 total patients

86.2 % of patients with ARF-D had an ICU stay > 3 days; compared with 19.2 % of patients withno ARF-D

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Documents

ImaCor White Paper: Clinical and Economic Benefits of ImaCor TEE Monitoring 2010-03*