Decreased peripheral perfusion measured by Perfusion Index is a novel indicator for cardiovascular death

[pattismith]

Decreased peripheral perfusion measured by perfusion index is a novel indicator for cardiovascular death in patients with type 2 diabetes and established cardiovascular disease

Okada, H., Tanaka, M., Yasuda, T. et al.

• Published22 January 2021
• DOIhttps://doi.org/10.1038/s41598-021-81702-w

• https://doi.org/10.1038/s41598-021-81702-w

Abstract

Cardiovascular disease (CVD) is still the major cause of mortality in patients with type 2 diabetes. Despite of recent therapies, mortality and resources spent on healthcare due to CVD is still important problem.

Thus, appropriate markers are needed to predict poor outcomes. Therefore, we investigated the role of peripheral perfusion as an indicator for cardiovascular death in patients with type 2 diabetes and established CVD.

This retrospective cohort study included 1080 patients with type 2 diabetes and history of CVD recruited from the outpatient clinic at Matsushita Memorial Hospital in Osaka, Japan.

Peripheral perfusion is assessed using the perfusion index (PI), which represents the level of circulation through peripheral tissues.

The median age and PI values were 74 years (range: 67–79 years) and 2.6% (range: 1.1–4.3%), respectively.

During follow-up duration, 60 patients died due to CVD.

The adjusted Cox regression analysis demonstrated that the risk of developing cardiovascular death was higher in the first quartile (Hazard ratio, 6.23; 95% CI, 2.28 to 22.12) or second quartile (Hazard ratio, 3.04; 95% CI, 1.46 to 6.85) of PI than that in the highest quartile (fourth quartile) of PI.

PI (per 1% decrease) was associated with the development of cardiovascular death
(Hazard ratio, 1.39; 95% CI, 1.16 to 1.68).

PI could be a novel indicator of cardiovascular death in patients with type 2 diabetes and established CVD.

Table 2

RESULT

Sixty patients died due to cardiovascular death during study period
(Quartile 1, 2, 3 and 4; 32,14,10 and 4, respectively).

Cardiovascular death included 11 myocardial infarction, 44 heart failure, and 5 stroke during study period.

One hundred and ninety-six patients developed the recurrent cardiovascular events during study period
(Quartile 1,2,3 and 4; 86, 48, 37 and 25, respectively).

Four patients developed myocardial infarction, 16 patients developed stroke, 120 patients received revascularization for angina and 56 patients received revascularization for peripheral artery disease (PAD).

 

[pattismith]

The effect of patient positions on perfusion index

• Hakan Tapar,
• 2018
• 
  
• 
  Background
  The optimal position for surgery is one in which the patient is provided the best possible surgical intervention and put at minimum risk. Different surgical positions may cause changes in tissue perfusion. This study investigates the relationship between surgical patient positions and perfusion index.
• 
  Methods
  A sample of 61 healthy individuals with no peripheral circulatory disorders, chronic diseases, or anemia was included in this study.
• Participants held six different positions:
• supine,
• prone,
• 45-degree sitting-supine,
• 45-degree supine with legs lifted,
• Trendelenburg (45-degrees head down), and
• reverse Trendelenburg (45-degrees head up).
• Perfusion index values were then measured and recorded after individuals held their positions for five minutes.

• 
  

  Results

  Participants’ perfusion index values were affected by different body positions (p < 0.05).
  [*]
  [*]Perfusion index was lowest in the sitting position (4.5 ± 2.5) and highest in individuals with Trendelenburg position (7.8 ± 3.8).

• 
  

  Conclusion

  Different body positions can cause changes in tissue perfusion. This should be considered in patient follow-up along with the perfusion index.

• DOI https://doi.org/10.1186/s12871-018-0571-z

• https://doi.org/10.1186/s12871-018-0571-z
  

 

[pattismith]

I tried to put my finger oxymeter on my toe, and found PI = 0.2 (supine)... I must be half dead

here how they measured Pi in the diabeter study:

PI was measured using a Masimo SET Radical-7 (Masimo Corporation, Irvine, CA) instrument. The patients were placed in the supine position. A Masimo pulse oximeter probe was positioned on each toe and connected to the Masimo SET Radical-7 machine. The patients were asked to rest for 5 min at the beginning of the procedure. PI was then recorded three times: at 20, 40, and 60 s, after the 5-min rest period. The average of the three values was calculated and used as the reference value. The Masimo SET Radical-7 calculates PI as the ratio between the pulsatile and non-pulsatile components of the light reaching a light-sensitive cell of the pulse oximetry probe. The reliability and reproducibility of PI have been reported elsewhere17,24. After PI was determined bilaterally, the lower value was considered as a representative for each subject.

Here what Massimo explain about PI:

Clinical Interpretation of the Perfusion Index Perfusion index is an assessment of the pulsatile strength at a specific monitoring site (e.g. the hand, finger or foot), and as such PI is an indirect and noninvasive measure of peripheral perfusion.

It is calculated by means of pulse oximetry by expressing the pulsatile signal (during arterial inflow) as a percentage of the nonpulsatile signal, both of which are derived from the amount of infrared (940 nm) light absorbed. 1

The PI value is relative to a particular monitoring site, (e.g. the fingertip or toe), of each patient as physiological conditions vary between monitoring sites and individual patients

........

Changes in PI can also occur as a result of local vasoconstriction (decrease in PI) or vasodilatation (increase in PI) in the skin at the monitoring site.

These changes occur with changes in the volume of oxygenated blood flow in the skin microvasculature. 2

The measurement of PI is independent of other physiological variables such as heart rate variability, SaO 2, oxygen consumption, or temperature.

The interpretation of PI depends on the clinical context to which it is applied.

The PI generally changes in proportion to peripheral perfusion.

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