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Key Study Findings - Anesthesia

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 reoperation 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.

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.

Reliability of Monitors During CEAs

AUC represents the probability that a randomly selected subject will have correct prediction of ischemia.


The reliability of four cerebral monitoring systems was compared in detecting cerebral ischemia, defined as obvious neurologic change, during awake carotid endarterectomy (CEA). The study found that:
  • Transcranial Doppler Sonography (TCD), near-infrared spectroscopy (NIRS) and stump pressure (SP) measurement provide statistically similar accuracy for the detection of cerebral ischemia during carotid surgery.
  • The performance of somatosensory evoked potentials (SEP) was significantly poorer.
  • Due to technical difficulties, TCD and SEP were unable to be performed on 21% and 4% of patients respectively, making them unreliable in a portion of the population.
  • SP and NIRS (INVOS® System) were possible in all patients, prompting investigators to state that the use of NIRS and/or SP "might be superior in clinical practice."

Footnote:
Moritz et al. Anesthesiology 2007;107:563-9.