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Key Study Findings - Adult Surgery/ICU

The following Key Study Findings are just a sample of the more than 600 compelling clinical presentations, study abstracts and published papers documenting INVOS® System benefits.

To see the full bibliography, please visit Clinical Evidence.

Improved Outcomes



A prospective, randomized and blinded study of 200 coronary artery bypass (CAB) patients1 showed that patients managed via the INVOS® System experienced:
  • Decreased major organ morbidity or mortality (MOMM)2: 3% vs. 11%, p=0.048
    - MOMM is a cumulative score of death within 30 days, permanent stroke, >48 hours ventilation, mediastinitis/deep sternal infection, renal failure requiring dialysis and re-operation for any reason
  • Fewer severe oxygen desaturations: 0 vs. 6, p=0.014
  • Shorter ICU length of stay: 1.25 ± 0.8 days vs. 1.87 ± 2.7 days, p=0.029

The study also showed an inverse relationship between mean intraoperative rSO2 and a hospital stay >10 days: p=0.063
  • Low cerebral rSO2 values were associated with "outlier" patients having the longest recovery times


Footnotes: 
1. Murkin JM, et al. Anesth Analg. 2007 Jan;104(1):51-8.
2. Shroyer AL, et al. Ann Thorac Surg. 2003;Jun:75(6):1856-64.

Shortened ICU Stay




Footnote:
Murkin JM, et al. Anesth Analg. 2007 Jan;104(1):51-8.

Fewer Outliers by Group (>10 days LOS)



Footnote:
Murkin JM, et al. Anesth Analg. 2007 Jan;104(1):51-8.

Improved Outcomes for Diabetics1



  • With INVOS® System monitoring, diabetic CABG patients charted statistically-significant decreases in vent time, ICU stay and hospital stay than unmonitored diabetics.
  • Interventions prompted by monitoring kept brain oxygenation adequate, enabling diabetics to achieve the same clinical outcomes as their non-diabetic peers.
  • The lead investigator stated this "essentially levels the playing field for patients who traditionally have had worse outcomes in cardiac surgery."2

    Footnotes:
    1. Murkin JM; Iglesias I; Bainbridge D; Adams S; Schaffer B; et al.
    Anesth Analg 2005;100:SCA101.
    2. The American Academy of Cardiovascular Perfusion (aacp),
    Academy Newsletter Spring 2006 Annual Seminar Review;8-10.

Associations with Cognitive Decline



A prospective and randomized study of 240 cardiac patients showed that decreased rSO2 predicts cognitive decline following coronary artery bypass grafting (CABG).
  • Low intra-op cerebral rSO2 values were significantly associated with, and predictive of, post-op cognitive decline (p=0.024)
  • They were also significantly associated with increased length of stay (> 6 days; p=0.007)

    Examples of Risk Score Calculation:

  • A risk score formula was created by multiplying the number of points < 50 rSO2 by time in seconds.
  • Any combination of intra-op rSO2 value and time that resulted in > 3000 %seconds was found to increase risk.

Footnote:
Slater JP, et al. Ann Thorac Surg. 2009 Jan;87(1):36-45.


Reduced Incidence of Stroke and Prolonged Ventilation


  • A study of 2,279 cardiac surgery patients found that cerebral oximetry via the INVOS® System reduced stroke rate, post-op ventilation time and hospital LOS.
  • These statistically-significant results were achieved despite the monitoring group having a much higher acuity level than the unmonitored group (64% in NYHA classes III and IV versus only 31%).


Footnotes:
1. Goldman et al. Heart Surgery Forum 2004;7(5):E376-81.
2. Goldman et al. Presented at Outcomes 2005, May 19-22, Key West.

Decreased Hospital Length of Stay




This trial showed that traditional global measures of cerebral well-being are indirect, and sometimes inadequate, indicators of regional ischemia.
  • One in five (20%) relatively healthy, elderly, abdominal surgery patients had a cerebral desaturation event below 75% of baseline.
  • Patients with desaturations without cerebral oximetry interventions had significantly lower post-operative Mini-Mental State Examination (MMSE) scores and longer PACU and hospital length of stays.
    -The INVOS® System monitored group with interventions had shorter mean hospital length of stay: 10 vs. 24 days, p=0.007.
  • None of the desaturation events were associated with concomitant reductions in pulse oximetry.
    The authors stated that, "Adjusting the anesthesia plan according to rSO2 monitoring allowed us to minimize the exposure of the brain to a potentially inadequate oxygen supply."

    Footnote:
    Casati A, et al. Anesth Analg. 2005 Sep;101(3):740-7.

    Improve rSO2 via Routine Interventions



    • To see a PDF version of this figure, please Click here.

    This study-based algorithm provides a step-by-step method to optimize the factors that can lead to cerebral desaturations during cardiac surgery when the INVOS® System is used. General enough to be used in any surgery or in the ICU, the algorithm (flow chart) clearly delineates a progressive process to correct abnormal rSO2.

    The flow chart lists the interventions in order of priority based on clinical experience.
    • Each intervention is accompanied by supporting information such as its physiological basis, experience in published studies by other centers and the authors' own experiences.
    • Significant improvements in outcome have been seen when the rSO2 was kept at normal levels. Baseline values should be obtained when the patient was awake, resting comfortably with O2 supplementation.
    • The investigators state, "Randomized trials performed in single centers have demonstrated clinical benefit of cerebral oximetry when employed with a strategic intervention algorithm."
    • Other studies have also shown the ability of routine interventions to correct oxygen desaturations 80-94% of the time. Even when complete correction is not possible, interventions can still result in incremental improvements.
      • Murkin CABG study; 56% desaturation rate (56/100 cases), with successful interventions in 80% of cases.
      • Ganzel CABG study; 67% desaturation rate (53/78 cases), with successful interventions in 94% of cases.

    Footnotes:
    1. Denault et al. A proposed algorithm for the intraoperative use of cerebral near-infrared
    spectroscopy. Semin Cardio Vasc Anesth 2007;11;274.
    2. Murkin JM, et al. Anesth Analg. 2007 Jan;104(1):51-8.
    3. Ganzel BL, et al. Multimodality neuromonitoring improves CABG recovery. Presented
    at Society of Thoracic Surgeons, Jan 2002, Ft. Lauderdale, FL.