Cardiopulmonary Dynamics:The role of oxygen in hemodialysis

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Cardiopulmonary DynamicsThe role of oxygen in
hemodialysis

• Anne Diroll, RN, CNN

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Non Invasive Vascular Monitoring

• Continuous Hct
• Continuous BV change
• Continuous O2 saturation
• Recirculation
• TQA

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Crit-Line Monitor Technology
Blood Flow

Blood Chamber
Emitter
Detector
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Samples from Radial artery vs Extracorporeal
arterial blood line

• No significant difference between values from
  radial artery and extracorporeal dialysis
  arterial blood line
• Obtaining samples from extracorporeal dialysis
  arterial blood line to evaluate parameters of O2
  status clinically convenient accurate
• Nielsen et al, Hvidovre, Denmark. Blood
  Purif 199917(4)206-12

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NIVM O2 Saturation Accuracy
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Cell Physiology

• Oxygen is necessary for all chemical reactions in
  the cells
• 25 trillion red cells - the most abundant cell in
  the body
• Guyton Hall, Chapter 1, pgs 3-5.

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HypoxemiaSignificance

• 56 of patients experience at least one episode
  of hypoxemia
• Heart ischemia is generally from an O2 supply
  deficit rather than an increased myocardial
  demand
• Death from ischemic heart disease is up to 20 x
  more prevalent then the general population
• Ischemia is one of the risk factors leading to
  CHF
• Hypoxemia is underestimated as an additional
  factor of chronic deterioration of CV System
• 
  
  
  Steuer 1995
• 
  

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Transport Utilization of O2

• Transfer of O2 across alveolar-capillary membrane
• Hemoglobin
• Cardiac Output
• Release of O2 from Hgb molecule
• Ability of cells to utilize O2

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Arterial Saturation

• L-U-N-G-S
• Arterial Blood Gases - invasive
• Pulse Oximetry - non-invasive/ calculated
• Crit Line - non-invasive/actual sat

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FISTULAE GRAFTS

• Arterial Blood
• Normal value 97
• Clinically significant if lt90

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Decreasing Arterial Sats..

• When patient dozing or asleep consider sleep
  apnea
• Dx present in 15 of general population
• Much higher in dialysis population
• Kuhlmann et al, Clin Neph June 2000

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Sleep Apnea

• 30.9 of ESRD pts showed evidence of sleep
  disordered breathing (40
  male/15 female)
• 16.4 met dx criteria for SAS
• (20 male/10 female)
• SAS promotes hypertension impairs quality of
  life
• Kuhlmann et al, Marburg, Germany. Clin Neph
  2000 Jun53(6)460-6

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TRALI

• Transfusion Related Acute Lung Injury
• Rapid onset of hypoxia
• Plasma containing products - whole blood (as
  little as 50mL), FFP (as little as
  70mL),platelets
• Mimics pulmonary edema, ARDS

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Venous Saturation

• H-E-A-R-T
• Venous Blood Gases - from venipuncture or
  speciman from pulmonary artery catheter/invasive
• Crit Line - non-invasive

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SvO2 ScvO2

• Mixed venous sat from pulmonary artery, and
  catheter venous sat from central vein, while not
  identical, are functionally equivalent
• Bauer et al

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Canine Study

• Compared pulmonary artery sat and venous catheter
  sat
• Over broad range of cardiorespiratory conditions
• Hypoxia,hemorrhage,resuscitation
• Correlation coefficient -179 simultaneously drawn
  blood samples - between pulm.art and ven.cath -
  0.97
• Key ScvO2 to trend O2 supply/demand

Reinhart et al, Chest,Vol 95,1216-1221, 1989
Am College of Chest Physicians
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CATHETERS

• Mixed Venous Blood
• Normal value 75
• Range 60-80
• lt60cardiac dysfunction
• lt35severe cardiac dysfunction

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Access Catheter

• SvO2

Venous Blood Lower O2 Saturation
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Fick Principle
Oxygen Uptake (ml/min)
CO (l/min)
Hgb (gm/dl) X 1.39 X (Sat art - Sat
ven)/100X10
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• Normal BP does not guarantee an adequate cardiac
  output. Recognition of hemodynamic instability
  requires monitoring of both BP and global
  perfusion. Consideration of venous hemoglobin
  oxygen saturation is a logical means of assessing
  the adequacy of cardiac output.

James Bailey, MD, PhD - Anesthesiology,Emory.
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Venous Sat vs. BP

• Canine - induced cardiac depression
• Labs,cSvO2,MBP,CO measured every 10 minutes
• CO cSvO2 vs. CO MBP
• Conclusion gt continuous mixed venous oxygen
  saturation, not mean blood pressure associated w/
  early bupivicaine toxicity in dogs

Canadian Journal of Anaesthesia 50376-381 (2003)
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Freysz Lenfant 1988

• Cardiac output appeared to be the 1st and most
  affected hemodynamic variable, whereas mean
  systemic blood pressure remained unchanged
  because of the compensatory increase in systemic
  vascular resistance.

European J Anaesthesiology 1988251-60
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Pediatric Superior Vena Cava Saturation

• What is the critical level of venous oxygen
  saturation to maintain aerobic metabolism in
  neonates after the Norwood Procedure for
  hypoplastic left heart syndrome?
• An analysis of acid-base changes revealed an
  apparent anaerobic threshold when SvO2 fell below
  30

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Conclusion

• Clinical management to maintain SvO2 above this
  threshold (30) yielded low mortality.
• Hoffman et al, Ann Thorac Surg
  20001515-1520
• Implication for Crit Line? The
  threshold has been established!

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Decreasing Venous Sats..

• are due to decreasing cardiac output
• Predictive of hypotension
• Sodemann et al, Germany Austria

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Importance of Venous Oximetry

• Unfortunately, the most frequently measured
  haemodynamic parameters -arterial blood pressure
  and HR- deliver the least information on cellular
  oxygenation
• Balance-Supply-Demand
• Bauer et al.

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CARDIAC FAILURE

• The inability of the heart to meet the tissue
  demands for oxygen at the cellular level

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CHF
on initiation of ESRD therapy, 31 of patients
had CONGESTIVE HEART FAILURE, or a hx of this
condition, 56 of whom had a recurrence of heart
failure during dialysis therapy 25 of patients
without heart failure at baseline developed de
novo heart failure during dialysis
therapy Harnett et al CHF in dialysis subjects.
KI,Vol47 (1995), pp884-890
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Goals of Therapy

• DECREASE the workload of the heart

• DECREASE retention of sodium water

• IMPROVE gas exchange

• INCREASE cardiac output myocardial contractility

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The Oxygen content of Whole blood.

• Normal value 20ml O2 / 100ml blood

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Carrying Capacity of Hemoglobin

• 1 gm Hgb can carry
• 1.39 ml O2
• therefore.
• 10 gm Hgb x 1.39ml 13.9 ml O2/100ml blood
  

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Hypoxia caused by anemia or abnormal Hgb
transport of O2
A small amount of extra oxygen (7-30) can be
transported in the dissolved state in the blood
when alveolar oxygen is increased to maximum even
though the amount transported by the Hgb is
hardly altered. This small amount of extra oxygen
may be the difference between life
death. Guyton Hall, Chapter 42, pg 491.
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Dialysis Induced Hypoxemia

• Pulmonary leukostasis gt cellophane dialyzers
• Hypoventilation gtdialysate composition/CO2 losses
  in dialysate
• Alkalosis gt Bohr effect increased affinity of
  Hgb for O2
• N.D. Vaziri _at_ UC Irvine JOAO,1982 AJM,Nov 1984

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Cold Dialysate for the Prevention of
dialysis-induced Hypoxia

• 3 dialysate temperatures - 34.5(cold),
  36.5(normal), 38.5(warm)
• Dialysate temp significantly affected PaO2
• Most patients benefitted from cold dialysate for
  prevention of hypoxia
• Hegbrant J, et al, Lund, Sweden. Blood Purif
  199715(1)15-24

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Signs Symptoms of Hypoxia

• SOB
• Tachycardia
• Hypotension
• Cramping
• Tachypneia
• Cyanosis
• Dizziness
• Nausea
• Blurred vision
• Confusion

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Consider Supplemental O2

• Arterial sat lt90
• Venous sat lt60
• Sleep apneia
• Respiratory rate gt24
• Pulse lt60 or gt100
• Systolic BP lt100
• Anemia

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Medicare Coverage of Home Oxygen Therapy

• COPD - 496
• Diffuse Interstitial Lung dz - 515
• Cystid Fibrosis - 277.0
• Bronchiectasis - 494
• Lung Ca - 162.9

• Pulm Htn - 416.0
• CHF - 428.0
• Chronic Cor Pulmonale - 416.9
• Erythrycytosis - 695.9
• Sleep Apnea - 780.51

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Case Study
Cramping
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Case Study
Pulmonary Vascular Congestion
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Case Study
Severe Cardiac Dysfunction
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Case Study
Sleep Apnea
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Case Study
Hypotension
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REFERENCES

• Jaeger Mehta, Assessment of DW in HD-An
  Overview, JASN 10392-403,1999
• Guyton Hall, Textbook of Medical Physiology,
  tenth edition, 2000
• Smith Kampine, Circulatory Physiology-the
  essentials, third edition, 1989
• Brewster Perazella, Cardiorenal Effects of the
  Renin-Angiotensin-Aldosterone System, Hospital
  Physician, June 2004, pp. 11-20.
• Agraharkar et al., Recovery of renal function in
  dialysis patients, BMC Nephrology, 2003 49.
• Rodriguez,Domenici,Diroll,Goykhman, Assessment of
  DW by monitoring changes in BV during HD using
  Crit-Line, Kidney International,Vol.68(2005),pp.85
  4-861
• Wallis,JP, TRALI, British Journal of Anaesthesia,
  2003, Vol. 90, No. 5 573-576
• ?P Bauer, K Reinhart, M Bauer , Significance of
  venous oximetry in the critically ill, Department
  of Anaesthesiology and Critical Care Medicine.
  Friedrich-Schiller-University. Jena. Germany

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• The End