Clinical Abstracts from Testimonials

Outcomes 2004 Goldman SM
Outcomes 2004 Murkin JM
Heart Surgery Forum 2003 Iglesias I
Soc Thorac Surg; Jan 28-30, 2002
PA Soc Thorac Surg; Oct 16-20, 2002
Outcomes 2001 Alexander JC
Anest Analg 2001;92:SCA86
Anesthesiology 2001;95:A-152
Anesthesiology 2000;92:A-399

Goldman SM, Sutter F, Ferdinand F. Interventions based on cerebral oximetry reduce
the incidence of prolonged ventilation and hospital stay in cardiac surgery patients. Presented
at Outcomes 2004: The Key West Meeting, May 19-23, 2004.

Outcomes 2004 Goldman SM

Interventions based on cerebral oximetry reduce the incidence of prolonged ventilation and hospital stay in cardiac surgery patients.

Goldman SM, Sutter F, Ferdinand F.

Division of Surgery, Main Line Health Center - The Lankenau Hospital & Institute for Medical Research, Wynnewood, PA 19096 USA.

INTRODUCTION: We previously demonstrated a statistically significant reduction in the incidence of permanent stroke in a 2,279-patient study of cardiac surgical patients managed with cerebral oximetry despite increased co-morbidities in the treatment group. We sought to determine if the study group experienced shorter hospital stays and ventilation times with respect to an earlier non-monitored control group.
METHODS: All cardiac surgery patients in the 3-year period between July 1, 2000 and June 30, 2003 were retrospectively analyzed using data entered into the hospital's STS database. Since cerebral oximetry monitoring was initiated on January 1, 2002, the 18-month periods before and after this date were considered the control (N=1245) and study (N=1034) groups. In the study group cerebral oxygen delivery and consumption variables were optimized to maintain cerebral oxygen saturation (rSO2) at or near preoperative baseline.
RESULTS: The treatment group had significantly higher incidence of renal failure, hypercholesterolemia, hypertension, chronic lung disease, peripheral vascular disease and had significantly higher New York Heart Association (NYHA) classifications. Other variables were similar in the two groups. Controlling for NYHA classification, a significant reduction in hospital stay days by class was demonstrated, p<0.046, Figure 1. Median hours on the ventilator were shorter in the study group, 4 vs. 5, p<0.0016, and the proportion of patients requiring prolonged ventilation was shorter in the study group, 6.8% vs. 10.6%, p<0.0014. This remained significant when controlling for preoperative NYHA class (p<0.0002, Figure 2).

Fig. 1 Mean hospital stay (days) by NYHA class

Fig. 2 Proportion of patients requiring prolonged vent (%) by NYHA class

CONCLUSION: Maintaining rSO2 at preoperative baseline reduced length of hospital stay and need for prolonged ventilation despite more co-morbidities.

Murkin JM, Adams S, Schaefer B, Irwin B, Fox S. Monitoring Cerebral Oxygen Saturation
Significantly Decreases Stroke Rate in CABG Patients: A Randomized Blinded Study. Presented
at Outcomes 2004: The Key West Meeting, May 19-23, 2004.

Outcomes 2004 Murkin JM

Monitoring Cerebral Oxygen Saturation Significantly Decreases Stroke Rate in CABG Patients:
A Randomized Blinded Study.

Murkin JM, Adams S, Schaefer B, Irwin B, Fox S.

Department of Anesthesia and Perioperative Medicine, University of Western Ontario, London, Ontario, Canada.

INTRODUCTION: Cerebral oxygen desaturation has been associated with prolonged intensive care unit and total hospital lengths of stay. This study prospectively evaluated the use of near-infrared spectroscopy (NIRS) to monitor the impact of interventions to improve regional cerebral oxygen saturation (rSO2) on postoperative outcome after coronary artery bypass surgery. METHODS: After ethics board approval and written informed consent, patients were age stratified and randomly assigned to Control group (Group C) or Intervention group (Group I). Both groups had bilateral frontal electrodes to measure rSO2 during the operation, in Group I patients the monitor was visible and efforts to keep the rSO2 on levels = 75% of preinduction value by sequentially increasing perfusion pressure, pump flow, PaCO2 (if < 35 mmHg), FiO2, decrease temperature (if > 370C), increase PaCO2 > 45 mmHg increase Hct (if < 20%); in Group C patients the monitor was covered and the patient was managed routinely. All patients were assessed by an independent observer for adverse clinical outcomes including respiratory failure, CT or MRI confirmed stroke, renal failure, Ml, or perioperative death, Statistical anaIysis was performed using the Chi-square or Fishers exact test with p< 0.05 required for significance. RESULTS: 186 patients were included in the study (93 Group C, 93 Group I). 4 clinical stokes were detected in Group C vs 1 clinical stroke in Group I (p < 0.01). There were significantly fewer adverse clinical outcomes in monitored vs control groups (p = 0.009).

CONCLUSION: Monitoring and maintaining rSO2 above 75% of pre-induction values was associated with a significant decrease in perioperative stroke rate and overall number of adverse clinical outcomes.

Iglesias I, Murkin JM, Bainbridge D, Adams S. Monitoring cerebral oxygen saturation significantly decreases postoperative length of stay:A prospective randomized blinded study. Heart Surgery Forum 2003;6:204. Also presented on May 22, 2003 at Outcomes 2003: The Key West Meeting, Florida.

Heart Surgery Forum 2003 Iglesias I

Monitoring Cerebral Oxygen Saturation Significantly Decreases Postoperative Length of Stay: A Prospective Randomized Blinded Study

Iglesias I, Murkin JM, Bainbridge D, Adams S

Department of Anesthesia and Perioperative Medicine, University of Western Ontario, London, Ontario, Canada.

INTRODUCTION: Cerebral oxygen desaturation has been associated with prolonged intensive care unit and total hospital lengths of stay. This study evaluated the use of near-infrared spectroscopy (NIRS) to monitor the impact of interventions to improve regional cerebral oxygen saturation (rSO2) on postoperative outcome after coronary artery bypass surgery.
METHODS: After ethics board approval and written informed consent, patients were age stratified and randomly assigned to Control group (Group C) or Intervention group (Group I). Both groups had bilateral frontal electrodes to measure rSO2 during the operation, in Group I patients the monitor was visible and efforts to keep the rSO2 on levels > or = to 75% of preinduction value by sequentially increasing perfusion pressure, pump flow, PaCO2 (if < 35 mmHg), FiO2, decrease temperature (if > 37°C), increase PaCO2 > 45 mmHg, increase Hct (if <20%); in Group C patients the monitor was covered and the patient was managed routinely. Statistical analysis was performed using the Wilcoxon Rank Sums (WRS) for asymmetrical distributions with p<0.05 required for significance.
RESULTS: 98 patients were included in the study (54 Group C, 44 Group I), neurological complications were detected in 6 patients from the Group C [3 strokes] and in 5 patients in Group I [no strokes], and were not statistically significant. When comparing Length of Stay-LOS-between the groups there was a significantly shorter LOS in the Group I with odds ratio in the control group for a 10 or more days length of stay in hospital of 7.58 (p=0.03).

CONCLUSION: Monitoring and maintaining rSO2 above 75% of pre-induction values was associated with a decreased length of stay in patients undergoing uncomplicated CAB surgery.

Ganzel BL, Cerrito PB, Edmonds HL. Multimodality improves CABG recovery. Presented at Society of Thoracic Surgeons Annual Meeting, Ft. Lauderdale, Florida, January 28-30, 2003

Soc Thorac Surg, Jan 28-30, 2002

Multimodality Neuromonitoring Improves CABG Recovery

Brian L. Ganzel, Patricia B. Cerrito*, Harvey L. Edmonds, Jr.**
Department of Surgery (Cardiothoracic), Mathematics*, and Anesthesiology** University of Louisville, KY

BACKGROUND: This study examined the clinical benefit of neurophysiolgic monitoring for CABG surgery. A single-surgeon, retrospective, case-controlled analysis as performed.
METHODS: Neurophysiologic monitoring was used in 78 CABG operations by one surgeon (BLG) during 1999-2000. Outcomes were compared with a group of 386 similar patients matched for age, sex and procedure code in which neuromonitoring was not used. Neuromonitoring consisted of 4-channel EEG with bispectral index, bihemispheric transcranial cerebral oximetry and transcranial Doppler ultrasonic measurement of left middle cerebral artery flow velocity and embolic activity. Neurologic complication included permanent and transient stroke and coma.
RESULTS: Neuromonitoring detected physiologic imbalance in cerebral perfusion/oxygenation or anesthetic maintenance in 67% (53/78) of cases. Cerebral oxygen desaturation occurred in 38% (30/78), while EEG bispectral index prompted adjustments in anesthetic delivery in 22% (17/78). Excessive or inadequate cerebral blood flow was detected by Doppler in 6% (5/78). All but 3 of these imbalances were corrected by simple adjustments of perfusion pressure, oxygen delivery or anesthetic administration. The table compares standard outcome measures in both groups.

Average hospital charges were 11% less (P=.03) in the monitored group.
CONCLUSION: Patients provided with multimodality neuromonitoring had a significantly reduced total incidence of neurologic complications, length of hospital stay and total charges. Reductions in other injuries were not statistically significant because of small sample size. The apparent multisystem benefit of neuromonitoring suggests value in individualized adjustment of perfusion, oxygenation and anesthetic delivery as well as supporting initiation of an adequately powered prospective randomized study.

Goldman S. Utilization of cerebral oximetric monitoring and optimized cerebral oximetry values decrease incidence of stroke for cardiac surgical patients. Presented during the 40th Annual Meeting of the Pennsylvania Association of Thoracic Surgery, October 16-20, 2002, Miami Beach, Florida.

PA Soc Thorac Surg Oct 16-20, 2002

Utilization of Cerebral Oximetric Monitoring and Optimized Cerebral Values Decrease Incidence of stroke for Cardiac Surgical Patients

Scott Goldman, MD

Division of Thoracic and Cardiovascular Surgery, Main Line Health Center - The Lankenau Hospital and Institute for Medical Research, Wynnewood, PA 19096, USA

Stroke and other neurological dysfunction occur in a finite number of patients who undergo cardiac operations. Efforts to diminish this often devastating outcome have included carotid artery screening, epiaortic ultrasound, single aortic clamping, off pump surgery, tight glucose control, hypothermia, etc.

Beginning in January 2002 a percutaneous cerebral oximeter was used in all patients undergoing cardiac surgical procedures. This was done as an evaluation to determine whether monitoring and optimizing cerebral oximetry values could decrease the incidence of stroke.

Three hundred sixty-two patients underwent cardiac surgical procedures utilizing cerebral oximetric monitoring from January 1, 2002 through June 30, 2002. There was one stroke in this group (0.29%). This was compared to seven hundred ninety-one patients who underwent cardiac surgical procedures without using cerebral oximetric monitoring from January 1, 2001 through December 31, 2001. There were fourteen strokes in this group (1.77%)

The patient group that underwent cardiac surgical procedures utilizing cerebral oximetric monitoring and optimized cerebral oximetry values demonstrated a marked decrease in the incidence of stroke.

(P=0.0062, student T-test)

Alexander JC, Kronenfeld MA, Dance GR. Reduced postoperative length of stay may result from using cerebral oximetry monitoring to guide treatment. Presented at Outcomes 2001, the Key West Meeting, May 23-26, 2001, Ann Thor Surg 2002;73 373-C.

Outcomes 2001 Alexander JC

Reduced postoperative length of stay may result from using cerebral oximetry monitoring to guide treatment.

JC Alexander, Jr., MD, MA Kronenfeld, MD, GR Dance, CCP

Hackensack University Medical Center, Hackensack, NJ 07601

INTRODUCTION: Renal failure and CNS events are causes of morbidity following OHS. The objective of this pilot study was to evaluate the incidence of renal failure and postoperative CNS events following OHS.
METHOD: 54 patients were monitored intraoperatively using the INVOS 4100 cerebral oximeter, readings were maintained at levels of 40 or greater. Interventions used to increase INVOS readings included increased pump flow, elevated perfusion pressures, augmenting CO2 levels and transfusions. The study group was compared to 1,131 patients operated on in the prior year who did not have INVOS monitoring. The demographics of both groups were similar:

RESULTS: STS database criteria were used to determine the incidence of renal failure and CNS complications, shown below with mortality and length of stay.

Interventions required to elevate the INVOS readings were surprisingly frequent (>50%). Low readings were relatively easy to correct. The absence of CNS and renal problems was reflected in reduced LOS.
CONCLUSIONS: These findings suggest that unappreciated hypoxia reflected in renal and CNS dysfunction may be responsible for morbidity that is preventable resulting in reduced LOS.

Yao FSF, Levin SK, Wu D, Illner P, Yu J, Huang SW, Tseng CC. Maintaining cerebral oxygen saturation during cardiac surgery shortened ICU and hospital stays. Anesth Analg 2001;92:SCA 86.

Anest Analg 2001;92:SCA86

Maintaining Cerebral Oxygen Saturation During Cardiac Surgery shortened ICU and
Hospital Stays

FSF Yao, MD; SK Levin, MD; D Wu, MD; P Illner, MD; J Yu, BS; SW Huang, BA; CC Tseng, MD

Department of Anesthesiology, Weill Medical College of Cornell University, New York, NY 10021

INTRODUCTION: Cerebral oxygen desaturation during cardiac surgery was associated with prolonged intensive care unit (ICU) and hospital stays. This study evaluated whether maintaining adequate cerebral oxygen saturation (rSO2) can shorten ICU and hospital stays. METHODS: After IRB approval and informed consent, 340 patients were monitored with cerebral oximeter during cardiac surgery. The control group consisted of 149 patients from September 1998 to July 1999. Surgery and anesthesia were performed as usual and no interventions were attempted according to cerebral oximetry. In the intervention group which included 191 patients from July 1999 to September 2000, we attempted to maintain cerebral oxygen saturation above 40%. The following interventions were performed in sequence as needed: increasing FIO2 to 100%; increasing PaCO2 to 40-45 mm Hg; increasing mean arterial pressure to > 80 mm Hg; increasing pump flow > 2.5 l/min/m2; increasing anesthetic depth; administering nitroglycerin 10-30 mcg/min; transfusing red packed cells if hematocrit <20%. The t-test and chi-square were performed for statistical analysis. P <0.05 was considered statistically significant. RESULTS: The intervention group had significantly shorter ICU and hospital stays, smaller area of rSO2 <30%, and lower incidence of area of rSO2 <30% more than 5 min % than the control group as shown in Table 1. There were no significant differences between the two groups in terms of age, gender distribution, incidence of severe atheromatosis of thoracic aorta, left ventricular ejection fraction <40%, history of diabetes mellitus, hypertension, transient ischemic attack, cerebral vascular accident, chronic renal failure and baseline rSO2. DISCUSSION: We demonstrated that maintaining adequate cerebral oxygen saturation during cardiac surgery significantly shortened ICU and hospital stays. Therefore, using cerebral oximetry may decrease total costs of cardiac surgery.

Yao FSF, Tseng CC, Woo D, Huang SW, Levin SK. Maintaining cerebral oxygen saturation during cardiac surgery decreased neurological complications. Anesthesiology 2001;95:A-152. http://www.asa-abstracts.com

Anesthesiology 2001; 95:A-152

Maintaining Cerebral Oxygen Saturation during Cardiac Surgery Decreased Neurological Complications

Fun-Sun F. Yao, MD; Chia-Chih Tseng, MD; Daniel Woo, MD; Suena W. Huang, BA;
Serle K. Levin, MD.

Department of Anesthesiology, Weill Medical College of Cornell University, New York, NY 10021

INTRODUCTION: Cerebral oxygen desaturation during cardiac surgery was associated with neurological complications. This study evaluated whether maintaining adequate cerebral oxygen saturation (rSO2) can decrease neurological outcomes.
METHODS: After IRB approval and informed consent, 286 patients without history of cerebral vascular accident and carotid artery disease were monitored with cerebral oximeter during cardiac surgery. The control group consisted of 125 patients from September 1998 to July 1999. Surgery and anesthesia were performed as usual and no interventions were attempted according to cerebral oximetry. In the intervention group which included 161 patients from July 1999 to September 2000, we attempted to maintain cerebral oxygen saturation above 40%. The following interventions were performed in sequence as needed: increasing FIO2 to 100%; increasing PaCO2 to 40-45 mm Hg; increasing mean arterial pressure to >80 mm Hg; increasing pump flow>2.5 1/min/m2; increasing anesthetic depth; administering nitroglycerin 10-30 Hg/min; transfusing red packed cells if hematocrit <20%. The t-test and chi-square were performed for statistical analysis. P <0.05 was considered statistically significant.
RESULTS: The intervention group had significantly lower incidence of stroke and coma, smaller area of rSO2 <30%, and lower incidence of severe atheromatosis of thoracic aorta, left ventricular ejection fraction <40%, history of diabetes mellitus, hypertension, transient ischemic attack, chronic renal failure, chronic obstructive pulmonary disease, and baseline rSO2.
DISCUSSION: We demonstrated that interventions to maintain adequate cerebral oxygen saturation significantly decreased neurological outcomes. Therefore, it is prudent to use cerebral oximetry during cardiac surgery.

Schmahl TM. Operative changes effecting incidence of perioperative stroke (IPS) using cerebral oximetry (CO) and aortic ultrasonography (AU). Anesthesiology 2000;93:A399. http://www.asa-abstracts.com

Anesthesiology 2000;92:A-399

Operative Changes Effecting Incidence of Perioperative Stroke (IPS) Using Cerebral Oximetry (CO) and Aortic Ultrasonography (AU)

T.M. Schmahl, M.D.

Cardiovascular Surgery, SLMC, Milwaukee, WI, United States

INTRODUCTION: Perioperative stroke (PS) may be a complication of coronary bypass surgery (CBS) or valvular cardiac surgery VCS). Two diagnostic techniques, CO and AU, were used to diagnose conditions potentially causative for PS. Based on the findings of CO and AU, operative and perfusion techniques were changed to avoid PS. METHOD: Multiple logistic regression analysis of risk factors was used to define a population of patients at risk for PS. These factors were found to be predictive of PS: age, gender, hypertension, emergency admission, previous stroke, and presence of cerebral or peripheral vascular stenosis. All patients in the population found to be at significant risk for PS were operated on by the same surgeons, the same anesthesiologists, and the same group of cardiopulmonary perfusionists utilizing identical cardiopulmonary perfusion equipment. The study group was selected prospectively and underwent CBS and/or CVS between October of 98 and December of 99 utilizing the diagnostic tools of CO and AU. Findings obtained from CO and AU were used to change perfusion and operative technique to decrease PS. A drop of 25% or more in CO or a divergence of 25% or more between the right and left cerebral hemispheric oximetric reading triggered changes in technique. These intraoperative changes included changing aortic cannulation site, adjusting venous return cannula, increasing bypass flow rates, transfusion of packed red blood cells, adjusting pCO2, adjusting pO2, and adjustment of mean perfusion pressure. AU was carried out to diagnose conditions of the aorta that could lead to PS. Alterations in operative technique included selection of aortic cannulation site, optimal site of placement of aortic clamp, optimal site of vein graft anastomosis, use of no touch aortic techniques. The first control group underwent CBS and/or CVs between October of 97 and September of 98. This group had been defined prior to this study as having a high PS. The second control group underwent CBS and/or CVs between October of 98 and December of 99. The purpose of the second control group was to be able to compare hospital charges during the like economic periods. The study and control groups were then evaluated for incidence of PS, days from operation to discharge, and hospital charges. RESULTS: Statistical significance in () following result, Chi Square Method, ns = not statistically significant, na = not applicable.
DISCUSSION: PS can be a devastating, permanent insult that has a profound impact on patients and their families. The most important result of this investigation was a nearly fivefold decrease in the PS rate in the study group. The economic impact of the decrease in stroke rate amounted to a more than 10% decrease in hospital charges, or $1,500,000. These beneficial effects are achieved using techniques that are noninvasive, inexpensive and harmless.

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