CONSULTANT DEPARTMENT OF ANESTHESIOLOGY RAND MEMORIAL HOSPITAL FREEPORT BAHAMAS

Classification of HES Degree of Hydroxyethylation  0.7 HetastarchHespan ®, Plasmasteril ®  0.6 HexastarchElohes ®  0.5 PentastarchHAES-Steril ®, Pentaspan ®, Hemohes ®  0.4 TetrastarchVoluven ®,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 VOLUVENVENOFUNDIN TETRASPAN Raw MaterialWaxy cornPotato Molecular weight130 kD Molar substitution C2 : C69 : 16.4 : 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 is a better product because of Remains intra-vascularly for a longer time Proven to have minimal interference with coagulation Minimal or no influence on renal function Proven to improve microcirculation As opposed Potato based may interfere in coagulation Efficacy 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 Fluid L Interstitial Fluid L Intra vascular Fluid 3 L Trauma induced fluid transfer 2 – 3 L 1 L Crystalloid Infusion 1 L 0.8 L 0.2 L Colloid Infusion 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: ]

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 groups 1)RL group 2)Gelofusin group 3)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, SaO 2 O 2 inhalation-not started till substantial fall i.e. SaO 2 of 92-93% (fall of 7-8%) Additional 500 ml RL/200 ml Gelofusin/200 ml Voluven infused

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

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 SaO 2 values No requirement of additional O 2 supplement

Recommended indications of Tetrastarch Intra-operative stability for preloading before SA May improve circulation/ O 2 delivery in vasculo- compromised areas May be beneficial in micro-vascular problems : ARDS, SHOCK etc.

ADDITIONAL INDICATIONS As an alternative to blood transfusion In burn patients to improve PCOP In 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 SaO 2 IMPROVES MICRO – CIRCULATION NO INTERFERENCE WITH COAGULATION EXCELLENT INTRA-OP COURSE REAL “BLOOD ALTERNATIVE” VERSATILITY AND CONSISTANCY