Volume Therapy: Orientation & Expectations!

CONSULTANTDEPARTMENT OF ANESTHESIOLOGY

RAND MEMORIAL HOSPITALFREEPORTBAHAMAS

DR. MRIDUL M. PANDITRAO

Classification of HES

Degree of Hydroxyethylation

0.7 Hetastarch Hespan®, Plasmasteril®

0.6 Hexastarch Elohes®

0.5 Pentastarch HAES-Steril®, Pentaspan®, Hemohes®

0.4 Tetrastarch Voluven® ,Venofundin® , Tetraspan®

Actual knowledge

Serumwerk Bernburg developed a HES 130/0.42/6,4:1 from a potato-based starch

BBraun and Serumwerk Bernburg market the product in saline and balanced solutions

VOLUVEN VENOFUNDINTETRASPAN

Raw Material Waxy corn Potato

Molecular weight 130 kD 130 kD

Molar substitution 0.4 0.42

C2 : C6 9 : 1 6.4 : 1

Waxy maize based HES and potato-based HES differ significantly in their chemical fine structure:

– Degree of branching (amylose content)– C2:C6 ratio– Free and total phosphate

Their pharmacological and clinical equivalence remains to be proven

Voluven vs Potato-based HES

Voluven vs Potato-based HES

Voluven is a better product because of Remains intra-vascularly for a longer timeProven to have minimal interference with

coagulation Minimal or no influence on renal functionProven to improve microcirculation As opposed Potato based may interfere in coagulationEfficacy may not be as good as voluven

Need to replace volume

• In cases of severe blood loss: Shock – Sepsis – Burns – Surgery - Trauma

• Where there is large loss of blood and fluid, the volume is required to be replaced to maintain cardiac index and oxygen delivery

• Saving of donor blood: elective surgery• Therapeutic hemodilution: stroke, PAOD• Volume preload in spinal anesthesia

Spinal Anaesthesia Pathophysiology

Hypotension in SA

• The commonest complications associated with spinal anesthesia are hypotension and bradycardia [1]

• Hypotesnsion- common significant cause of peri-operative morbidity and mortality

• Prior to SA- preloading with crystalloid is recommended to reduce the incidence of hypotension, although its value has been questioned [2]

Intra cellular Fluid25 - 28 L

Interstitial Fluid10 - 11 L

Intra vascular Fluid3 L

Trauma induced fluid transfer

2 – 3 L 1 L

Crystalloid Infusion

1 L

0.8 L

0.2 L

Colloid Infusion

1 L

1 L

Plasma Volume Restoration: Crystalloids vs Colloids

Retention of all colloids is not same

Crystalloids- General Disadvantages

• Crystalloid solutions- a short intravascular half-life

• Crystalloids- poor plasma volume expanders

• So, hypotension associated with spinal anesthesia cannot be completely eliminated by crystalloid preloading

• Large volumes of crystalloid fluid decrease oxygen-

carrying capacity, and may increase the risk of pulmonary and peripheral edema

• Colloid solutions which remain in the circulation for a longer period seem to be an effective alternative.

[2. Anaesth Analg 1997; 84: 111-114]

Generations of starches

*

Colloids

• Improved hemodynamic effects during spinal anesthesia after the administration of colloid solutions [3, 4].

• However, the ideal fluid regimens for elderly patients scheduled for spinal anesthesia is controversial [4, 5, 6].

Our study

With this background in mind, study was designed to compare the efficacy of new generation HES 130/0.4 (Tetrastarch) with various preloading solutions in overcoming the problems of SAIH

• Sixty adult patients• ASA I/II

• Both males/females•Elective major orthopedic

Surgical procedures• Under SA/EA+SA

• Ethics committee clearance• Informed consent

• Randomized in 3 groups1) RL group

2) Gelofusin group3) Voluven group

• Demographically matched

• 500 ml RL/300 ml Gelofusin/300 ml Voluven • Infused within 20 minutes

• Planned regional technique achieved• Monitoring continued- HR, MAP, ECG, SaO2

• O2 inhalation-not started till substantial fall i.e. SaO2 of 92-93% (fall of 7-8%)

• Additional 500 ml RL/200 ml Gelofusin/200 ml Voluven infused

96.2

81.91

97.4

79.29

86.88 87.79

0

10

20

30

40

50

60

70

80

90

100

RL Gelofusin Voluven

Comaprison of Mean MAP in 3 groups

Before SAAfter SA

P < 0.05

RESULTS

• MAP after SA was statistically significantly reduced in RL group as compared to that in Voluven group (p < 0.05)

• MAP after SA was statistically significantly reduced in Gelofusine group as compared to that in Voluven group (p < 0.05)

• MAP rather improved in Voluven group after S A

30

50

5

0

5

10

15

20

25

30

35

40

45

50

RL Gelofusin Voluven

% of patients requiring oxygen supplementation

%

RESULTS

• 50% ( 10 pts.) in Gelofusin and 30% ( 6 pts.) in RL groups required oxygen supplementation after S A

• Only 5% ( 1pt.) required oxygen supplementation after S A in Voluven group

• Clinically no significant excessive oozing/ bleeding in any one of the groups (inclusive of Voluven)

• 20 % ( 4 pts.) in Gelofusin group had allergic reactions like shivering, rashes and hypotension

Mechanism!

• “Tetrastarch decreases viscosity, increases

laminarity of flow”

• Leads to improved microcirculation; peripheral as

well as pulmonary

• Improves gaseous exchange

• Confirmed by consistently high SaO2 values

• No requirement of additional O2 supplement

Recommended indications of Tetrastarch

• Intra-operative stability for preloading before SA

• May improve circulation/ O2 delivery in vasculo-compromised areas

• May be beneficial in micro-vascular problems : ARDS, SHOCK etc.

ADDITIONAL INDICATIONSAs an alternative to blood

transfusionIn burn patients to improve PCOPIn neurosurgery patients to

decrease the viscosity of blood and to improve the cerebro-vascular perfusion

In the patients of Vascular Graft surgeries to improve the patency of graft

ADDITIONAL INDICATIONS

“JEHOVAH’S WITNESSES” : A novel indication

• Absolute refusal to accept blood &

blood products !• Extremely dilemmatic & peculiar

situation• Especially emergency, unplanned &

life saving surgery

SUMMARIZING

• TETRASTARCH GOOD PRE-LOADING• IMPROVES SaO2

• IMPROVES MICRO – CIRCULATION• NO INTERFERENCE WITH

COAGULATION• EXCELLENT INTRA-OP COURSE• REAL “BLOOD ALTERNATIVE”• VERSATILITY AND CONSISTANCY