Transfusion and blood

05/05/2010

Pediatric Transfusion PracticesDr Gary Simon

•Physiology•Differences between adult and neonate•Implications

•Transfusion reactions•Acute transfusion reactions•Delayed transfusion reaction•Coagulopathy •Transmission of infectious diseases •Sepsis•Metabolic changes•Physicial

Dept of Anesthesiology and Perioperative Care

Pediatric Transfusion Practices

• Blood Conservation• Preoperative Autologous Donation• Preoperative Erythropoetin• Acute Normovolemic Hemodilution• Antifibrinolytics• Intraoperative Blood Salvage• Controlled hypotension• Topical agents• Temperature control

05/05/2010

Pediatric transfusions - Physiology

• Physiology differences neonate vs child/adult– Children have higher oxygen consumption and a higher cardiac

output to blood volume ratio than adults – The neonatal myocardium operates at near maximum level of

performance as a baseline.– The newborn’s heart may be unable to compensate for a

decreased oxygen carrying capacity by increasing cardiac output.

– The neonatal myocardium will also suffer a greater degree of decompensation when exposed to decreased oxygen delivery.

05/05/2010

Pediatric transfusions - Physiology

• Fetal hemoglobin (HbF) comprises 70% of full term and 97% of premature infants’ total hemoglobin at birth. Red blood cells (RBCs) containing HbF have a shorter life span (90 days) than those containing primarily adult hemoglobin (HbA) (120 days)

• HbF interacts poorly with 2,3,DPG. Therefore the P50 decreases from 26 mmHg with HbA to 19 mmHg with HbF

• The optimal hemoglobin values in the newborn are higher than those of older patients (14-20 g/dl).

• Physiologic nadir for hemoglobin occurs at approximately 2–3 months of age (term -11, prem – 9.5)

05/05/2010

Pediatric transfusions - Physiology

05/05/2010

Pediatric transfusions - Physiology

• The P50 decreases from 26 mmHg with HbA to 19 mmHg with HbF. This leftward displacement of the oxygen–hemoglobin dissociation curve means decreased oxygen delivery to tissue because of the high affinity of HbF for oxygen.

• HbF production diminishes until only a trace is present at 6 months of age.The younger the infant, the higher the fraction of HbF and thus the lower the oxygen delivering capacity.

• Hemoglobin levels that are adequate for the older patient may be suboptimal in the younger infant or neonate.

05/05/2010

Pediatric transfusions - Physiology

05/05/2010

Pediatric transfusions -Physiology

• Immature coagulation system in neonate and is not comparable with adult level until six months of age.

• Main differences:– vitamin K dependent factors (II, VII, IX, X) that are less than 70%

of adult levels– inhibitors of coagulation (including antithrombin III and proteins

C and S) are 50% of adult levels– Platelets numbers are at a similar level to that of adults but take

2 weeks to develop adult levels of reactivity

05/05/2010

Blood volume (neonate to adult)

Age Blood Vol ml/kg

Age Blood Vol ml/kg

Preterm 90–105 4-6 yr 80–86

Term 78–86 7-18 yr 83–90

1-12 mnth 73–78 Adults 68–88

1-3 yr 74–82 TACO Small blood volumes

05/05/2010

• Acute transfusion reactions– Acute hemolytic reaction– Febrile nonhemolytic reaction– Urticarial/allergic reaction– clerical error

• Delayed transfusion reaction• Coagulopathy

– Thrombocytopenia– Decreased clotting factors

• Immune– TRALI– Immunomodulation

Transfusion reactions

05/05/2010

Transfusion reactions

• Transmission of infectious diseases• Sepsis• Metabolic changes

– Electrolyte - ↑K+; ↓Ca++; ↓Mg++– Acid Base– shifts in the oxygen–hemoglobin dissociation curve

• Physicial– Volume overload– Temperature

05/05/2010

Transfusion reactions - acute

• Acute hemolytic reaction– preformed IgM antibodies to ABO antigens

• result of blood group incompatibility• fever, chills, tachycardia, hypotension, shock, coagulopathy• hemolytic reactions due to ABO incompatibility rarely occur in

young infant (<4 mo) due to immature immune systems

– non-ABO antigens involve IgG-mediated reactions• often are delayed (ie, 2 to 10 days)• not detected by pretransfusion testing, because they

represent an anamnestic response• Rh disease most likely involving the immigrant population

05/05/2010

Transfusion reactions - acute

– Transfusion-related graft vs host disease • foreign lymphocytes in immunocompromised patients

proliferate causing host tissue destruction. Pancytopenia that develop 1–6 wks after a transfusion

• At risk patient includes - premature infants, children suffering from cancer or severe systemic illness, children experiencing rapid acute blood loss, and cardiopulmonary bypass

• immunocompetent children who receive directed donor transfusion from a biological relative

• Gamma-irradiation of blood renders donor lymphocytes incapable of proliferating

• High mortality rate (90%)

05/05/2010

Transfusion reactions - acute

• Febrile nonhemolytic reaction– 0.5% to 1.5% of red cell transfusions– host antibody response to donor leukocyte antigens– common in previously transfused patients– Use leukocyte-poor PRBCs– antipyretics, antihistamines, and corticosteroids

• Nonimmune hemolytic transfusion reactions– temperature (eg, overwarming with blood warmers, microwave

ovens) , hypotonic solutions– mechanical damage during administration (ie, pressure infusion

pumps, pressure cuffs, and small-bore needles)

05/05/2010

Transfusion reactions - urticarial/allergic

• Severe anaphylactic reactions occur infrequently• Reaction to donor plasma proteins• Manifestations include IgE-mediated symptoms involving

the skin, respiratory, GI or circulatory systems.• Anaphylactoid reactions with bronchospasm, laryngeal

edema and urticaria typically occur in IgA-deficient individuals.

• Rx includes antihistamines, steroids and sympathomimetics

• Use washed or filtered RBCs with the next transfusion

05/05/2010

Transfusion reactions - delayed

• Delayed transfusion reaction:– due to minor blood group antigen incompatibility– fatigue, jaundice, and dark urine– 3 to 10 days after transfusion– Laboratory findings include anemia, a positive

Coombs test, new RBC antibodies, and hemoglobinuria.

05/05/2010

Transfusion reactions – dilutional coagulopathy

• dilutional thrombocytopenia– normal patients: a platelet count

greater than 50 000 mm3 is required in order to maintain hemostasis

– chronically thrombocytopenic may not have bleeding tendencies even when the platelet count is in the 10 000–20 000 mm3 range

Blood volume

loss

% platelet decrease

from baseline

1 40%

2 20%

3 10%

– platelet counts which begin as normal (>150 000 mm3) are unlikely to be the cause of clinically significant coagulopathy until three blood volumes have been transfused (ie platelet count down by 70% from baseline).

05/05/2010

Transfusion reactions – dilutional coagulopathy

• dilution of clotting factors depends upon the type and volume of transfused blood– whole blood contains all clotting factors including fibrinogen at

normal values except for the labile factors (FV and FVIII); even these factors are present in 20–50% of their normal values. Pathological coagulation generally does not occur until 3+ blood volumes have been lost if whole blood being infused.

– PRBCs - approximately 80% of the coagulation factors have been separated into the plasma fraction. Clotting factor deficiency likely once blood loss exceeds one blood volume.  

05/05/2010

Transfusion reactions

• Immune– Transfusion Related Acute Lung Injury

• 1 in 5000 transfusions. In most cases the reaction occurs within 30 minutes to 2 hours (may occur up to 6 hours after).

• pathophysiology is still unclear• platelet concentrates derived from whole blood are most

commonly implicated, followed by fresh-frozen plasma, packed red blood cells, whole blood, granulocytes, cryoprecipitate and intravenous immunoglobulin

• acute onset of severe hypoxemia, bilateral noncardiogenic pulmonary edema, tachycardia/hypotension, and fever.

• most common cause of major organ dysfunction secondary to blood product administration

• In 2006, TRALI was the leading cause of transfusion-related death reported to the FDA (35 deaths, 50.7% of transfusion-related fatalities). Differential diagnosis - TACO05/05/2010

Transfusion reactions - Immune

• Immunomodulation– Alloimmunization to HLA antigens, which occurs commonly (ie,

20% to 70% of the time) in transfused and multiparous patients. Three manifestations:

• immune-mediated platelet refractoriness (insignificant rise in platelet count)• febrile non hemolytic transfusion reaction• autoimmune hemolytic anemia• post-transfusion purpura (platelet antibodies) 5 to 10 days post transfusion

– beneficial effects: improved renal allograft survival, reduced risk of recurrent spontaneous abortion, and reduced severity of autoimmune diseases such as rheumatoid arthritis.

– detrimental effects: increased cancer recurrence, perioperative infections, multiorgan system failure, and +/- overall mortality

05/05/2010

Transfusion - infectious diseases

• Units tested for:– Hepatitis B Surface Antigen ; Syphilis – Antibodies to Hepatitis B core antigen, Hepatitis C Virus, Human

T-cell Lymphotropic Virus (1 and 2), Human Immune Deficiency Virus (1 & 2)

– Nucleic Acid Testing for presence of HCV RNA, HIV-1 RNA and West Nile Virus RNA

05/05/2010

Transfusion - infectious diseases

• Transmission risk of infectious diseases– HIV 1/725,000–835,000; HTLV 1/641,000; parvovirus, 1 in

10,000 hepatitis B 1/63,000–500,000; hepatitis C 1/250,000–500,000

– CMV, hepatitis A, parasitic diseases (eg, malaria, babesiosis, toxoplasmosis, and Chagas’ disease), and variant Creutzfeldt–Jakob disease (vCJD)

– syphilis, Epstein-Barr virus, leishmaniasis, Lyme disease, brucellosis, B-19 parvovirus (increased prevalence in hemophiliacs), tick-borne encephalitis virus, Colorado tick fever virus, severe acute respiratory syndrome (SARS), West Nile virus, human herpes viruses

05/05/2010

Transfusion - infectious diseases

• Sepsis– bacteria contamination (particularly platelets as they are stored

at room temperature)– 20 deaths per million units of transfused platelets– Occult donor bacteremia and contamination of the product

during collection have been the main avenues for entry of bacteria

• 70% of contaminates isolated were gram-positive bacteria; while 80% of fatalities were caused by gram-negative organisms. Better disinfection of skin at the phlebotomy site and diversion of the skin plug have helped.

• Asymptomatic donor bacteremia (eg a case of transfusion associated Staphylococcus aureus platelet contamination has been reported in a blood donor who had undergone a tooth extraction 3 hours prior to donation)

05/05/2010

• Hypocalcemia– Citrate is a chelating agent for calcium.– Degree of ionized hypocalcemia depends upon the blood

product transfused, the rate of transfusion, and hepatic blood flow/function

– Highest risk with fresh frozen plasma (FFP) and whole blood– Neonates have decreased ability to metabolize citrate– Management:

• Slow the rate of blood product infusion• Calcium chloride 5-10 mg/kg : gluconate 15-30 mg/kg

Pediatric transfusions - Metabolic changes

05/05/2010

Pediatric transfusions - Metabolic changes

• Hypomagnesemia– Usually associated with massive transfusion– result of citrate toxicity and is seen with its greatest severity

during the anhepatic phase of liver transplantation– magnesium sulfate (25–50 mg/kg) followed by an infusion of 30–

60 mg/kg)/24 h.

05/05/2010

Pediatric transfusions - Metabolic changes

• Hyperkalemia– Blood components with the highest levels of potassium include

whole blood, irradiated units and units approaching their expiration date

– Rate of rise of serum potassium values occurs quickly in pediatric patients with small blood volumes during large volume or exchange transfusions

– Interventions include using more recently donated blood and washing it before infusion

– Calcium chloride 5-10 mg/kg : calcium gluconate 15-30 mg/kg– Therapy includes - glucose and insulin, bicarbonate,

hyperventilation, β agonists, dialysis and Kayexalate

05/05/2010

CPDA-1 CP2D/AS-3 CPD/SAGM

Vol of anticoag/

pres’vative soln 63 ml 100 mL 100 mL

NaCl 0 mg 410 mg 877 mg

Dextrose 2000 mg 1100 mg 900 mg

Adenine 17.3 mg 30 mg 16.8 mg

Mannitol 0 mg 0 mg 525 mg

Na Citrate 1660 mg 588 mg 0 mg

Citric acid 206 mg 42 0 mg

Na phosphate 140 mg 276 mg 0 mg

Shelf life 35 days 42 days 42 days

Hematocrit 0.65-0.90 0.55-0.65 0.50-0.7005/05/2010

• SAGM RBC Leukocyte Reduced – Red cell concentrate prepared from approximately 480 ml whole

blood collected in 70 ml of CPD anticoagulant.– The unit is plasma reduced by centrifugation, platelet reduced by

either centrifugation or filtration and leukoreduced by filtration. RBC’s are resuspended in 100 ml of SAGM nutrient.

• CPD/SAGM– Citrate is an anticoagulant, phosphate is a buffer, and dextrose

is a red cell energy source.– Adenine allows RBCs to resynthesize adenosine triphosphate

(ATP) which extends the storage time. Mannitol helps maintain integrity of RBC cell wall.

• Stored at 1º-6º which slows the rate of glycolysis by 40 times. Shelf life 42 days.

Pediatric transfusions - Metabolic changes

05/05/2010

Pediatric transfusions - transfusion risks

• Acid–base changes– After donation, the RBC’s continue to undergo aerobic

metabolism and elevate dissolved carbon dioxide to 180–210 mmHg within several hours

– After oxygen expended anaerobic metabolism increases the lactic acid content

– Rapid blood transfusion may initially cause a transient combined respiratory and metabolic acidosis.

– Carbon dioxide is rapidly removed by the lungs; the small amount of lactic acid is rapidly buffered so that there is no net effect upon acid–base status

– As long as the patient is volume resuscitated there is no need for exogenous bicarbonate therapy

05/05/2010

Pediatric transfusions - transfusion risks

• Hypothermia results from– Unwarmed intravenous fluids – esp RBC’s– heat loss because of their large surface area to weight ratio and

relatively large head size– GA causes a shift in heat distribution from core to periphery– Radiation and convexion result in most heat loss– cool irrigation solutions, and cold operating rooms

• Hypothermia causes:– apnea, hypoglycemia, ↓drug metabolism– leftward displacement of the ODC– increases oxygen consumption (due to shivering and

nonshivering thermogenesis)– coagulopathy – +/- increase mortality

05/05/2010

Pediatric transfusions - replacement

• MABL = (starting hct - target hct)/starting hct x EBV• Higher target hct for:

– preterm and term infants, children with cyanotic congenital heart disease, large ventilation/perfusion mismatch, high metabolic demand, and children with respiratory failure

• Replacement:– Hct in packed RBCs is about 70%– Loss in excess of MABL x desired hct (30%)/0.7– Approximately 0.5 ml packed RBCs for each ml of blood loss

beyond the MABL

05/05/2010

Pediatric transfusions – guidelines

• RBC transfusions:– Leukocyte reduced– CMV neg– Less than 2-3 wks old

• Platelet transfusions– platelet count is less than 50 * 109/L– 5 mL/kg - 10 mL/kg causes a rise of platelets of 50 to 100 * 109/L

• Fresh frozen plasma– Maintain minimum of 30% plasma factor concentration– 10-15 ml/kg

• Cryoprecipitate– 1 unit /10 kg BW raises plasma fibrinogen by 50 mg/dl

05/05/2010

Pediatric transfusions - triggers

• Transfusion Requirements in Critical Care Investigators, Canadian Critical Care Trials Group. Hébert PC - N Engl J Med - 11-FEB-1999; 340(6): 409-17– Restrictive strategy: RBC’s transfused if the Hb < 7 g/dl and Hb

concentrations were kept at 7 - 9 g/dl; and a liberal strategy: in which RBC’s given when the Hb concentration < 10 g/dl and Hb concentrations were maintained at 10 - 12 g/dl

– CONCLUSIONS: A restrictive strategy of red-cell transfusion is at least as effective as and possibly superior to a liberal transfusion strategy in critically ill patients, with the possible exception of patients with acute myocardial infarction and unstable angina.

05/05/2010

Pediatric transfusions - triggers

• Pediatric red blood cell transfusions increase resource use, Allyson M. Goodman - Journal of Pediatrics Vol 142 • Num 2 • Feb 2003– 3 groups: hemoglobin 6.5 to 7.4 g/dL (54 patients), 7.5

to 7.9 g/dL (40 patients), and 8 to 9 g/dL (105 patients); 131 were transfused and 109 were not transfused

– significant increase in hospital and intensive care resources used for transfused patients. PICU and hospital length of stay significantly increased by more than 4 days and 7 days, respectively, and there was substantial increases in the use of oxygen, mechanical ventilation, and vasoactive agent infusions.

– retrospective multicenter analysis rather than a randomized clinical trial.

05/05/2010

Pediatric transfusions - neonates• Neonates have some specific

considerations with respect to anesthesia and blood products.– Major hemolytic reaction (ABO)

occurs less frequently in neonates compared with older children and adults.

– For the first 3–4 months of life, infants are unable to form alloantibodies to RBC antigens.

– After 4 months of age, hemolytic reactions become a potential factor

05/05/2010

Pediatric transfusions – special considerations

• Tonsillectomy:– majority of early bleeding episodes occur within the first 4–6 h

after the procedure. Late bleeding occurs 5–10 days postoperatively

– Several studies have demonstrated increased perioperative bleeding associated with ketorolac use for analgesia following tonsillectomy.

• Can J Anaesth - 01-JUN-1996: Preoperative ketorolac increases bleeding after tonsillectomy in children.– Study terminated early due to interim analysis revealing ↑ risk.– Consclusion: “Preoperative ketorolac increases perioperative

bleeding among children undergoing tonsillectomy without beneficial effects.”

05/05/2010

Blood Conservation

• Preoperative Autologous Donation• Preoperative Erythropoetin• Acute Normovolemic Hemodilution• Antifibrinolytics• Intraoperative Blood Salvage• Controlled hypotension• Topical agents• Temperature control

05/05/2010

Blood Conservation - PAD• An analysis of a preoperative pediatric autologous blood

donation program. Can J Surg (2000) 43 : pp 125-129– 173 patients (ages 8-19) with mininum Hb 110. 400 ml removed

if weight >45 kg; less for those < 45 kg. Scoliosis repair.– Preoperative Autologous Donation - Children younger than 10

years or weighing less than 40 kg were included had a compliance rate at or above 70%, with the compliance rate in adolescents equal or superior to that of adults.. Allogeneic transfusion rate was 26.6%

– Wastage rate (percentage of blood units that were unused and discarded) in these studies varied from 6% to 31% of the total number of donated units

– When PAD was the sole blood conservation method, 73% to 89% of subjects avoided allogeneic transfusion.

– The addition of deliberate hypotension to PAD resulted in a 10% allogeneic exposure rate.

05/05/2010

Blood Conservation - PAD

• Unique pediatric PAD problems:– Smaller total blood volume – smaller donation volumes– Inability of younger children to tolerate repeated vascular access– Deep sedation or general anesthesia in infants and toddlers for

interval of time to remove blood.– must be a candidate for elective surgery where blood transfusion

likelihood is high– admission and operation days must be guaranteed– Sufficient time to enable optimal collection of the blood prior to

surgery (limited by five week window for stored blood)– Same transfusion triggers - many units wasted

• Directed donations – risk of Graft Versus Host Disease

05/05/2010

Blood Conservation - PAD

• Transfusion Medicine, 2007: Guidelines for policies on alternatives to allogeneic blood transfusion. Predeposit autologous blood donation and transfusion.

• PAD is not recommended unless exceptional circumstances may include: – Rare blood groups where allogeneic blood is difficult to obtain– Children with scoliosis (Ib, A)– Patients at serious psychiatric risk if blood transfusion is thought

to be likely to cover their elective surgery – Patients who refuse to consent to allogeneic transfusion but who

would consent to PAD

05/05/2010

Blood Conservation erythropoietin

• Erythropoietin is produced in the kidney – 90%; liver, brain, uterus, lung – 10%

• receptor is on the surface of erythroid cells. EPO is necessary for the survival, proliferation & differentiation of these cells.

• rate of hematocrit increase varies in patients and may be dose dependent

• an increase in reticulocyte count within 10 days, whereas a clinically significant increase in hematocrit should be present by 2 weeks (depending on existing iron stores)

05/05/2010

Blood Conservation erythropoietin

• Side effects are headache, fever, nausea, anxiety, and lethargy. Hypertension and hyperkalemia are seen in up to half of patients who are on dialysis

• Hyperviscosity syndromes related to high hematocrits - myocardial infarction, seizure, stroke and other thromboembolic events.

• Combined with dehydration, athletes are especially at risk for sudden death.

• Another rare, but serious, side effect is an autoimmune form of pure red cell aplasia that has been linked with SQ administration of rHuEPO

05/05/2010

Blood Conservation –Preoperative Erythropoieten

• Children who received EPO (300 U/kg three times per week for 3 weeks preoperatively) had significantly higher Hct values (43%) on the day of surgery compared with historical controls (Hct 35%) and had a 36% reduction in allogeneic transfusions. J Neurosurg (1998)

• Children undergoing surgery for idiopathic scoliosis who received EPO required fewer transfusions and had shorter hospitalizations. Pediatr Orthop B (1998)

• Preoperative erythropoietin significantly raised starting hemoglobin levels and reduced the need for a blood transfusion with craniosynostosis correction (30 of 30 contols vs 19 of 30 treated). Plast Reconstr Surg (2002)

05/05/2010

Blood Conservation -ANH

• removal of whole blood after induction with replacement

with crystalloid/colloid to maintain normovolemia.• Autologous plasma, platelets and RBC’s are returned

after major blood loss • Children tolerate Acute Normovolemic Hemodilution

better than adults (lower comorbid disease)• Lowest Hct (9-17) in small studies revealed no lactic

acidosis or decreased oxygen consumption. This would suggest that critical oxygen delivery was not reached.

• Younger than 4 to 6 months of age are not ideal candidates (myocardial performance and fetal hemoglobin issues)

05/05/2010

Blood Conservation -ANH

• Few small studies evaluating ANH in avoidance of allogenic blood in pediatrics. Tend to indicate a reduction in allogenic transfusion

• ANH in spinal fusion surgeries have shown to be beneficial especially if combined with other blood conserving strategies

05/05/2010

Blood Conservation -ANH

• Evaluation of acute normovolemic hemodilution for surgical repair of craniosynostosis. Hans J Neurosurg Anesthesiol 2000– Craniosynostosis repair in 34 healthy patients 1992-1996.– 17 had mean of 122 ml blood removed after induction. Average

weight 8 kg (blood vloume ~ 640 ml), preop Hct 33.– 15/17 vs 14/17 had homologous transfusions (~ 110 ml in both

groups)– “In conclusion, acute normovolemic hemodilution reduces

neither the incidence of homologous blood transfusion, nor the amount of blood transfused in our series of patients undergoing complete surgical correction of craniosynostosis.”

05/05/2010

Antifibrinolytics

• ε-aminocaproic acid and tranexamic acid– synthetic lysine analogs that competitively inhibit activation of

plasminogen to plasmin– tranexamic acid has a longer half-life, is 7 to 10 times more

potent, and is more active in tissue than aminocaproic acid

• Chauhan S, et al. Comparison of epsilon aminocaproic acid and tranexamic acid in pediatric cardiac surgery. J Cardiothorac Vasc Anesth 2004; 18(2):141–3.– Both agents were equally effective in decreasing blood loss and

blood product requirement compared to controls for cardiac surgery

• Similar benefit has been documented for scoliosis surgery

05/05/2010

Blood Conservation – Intop Blood Salvage

• Cell Saver– Few pediatric studies with conflicting results– Smaller pediatric “bowls” have been developed, but the ability to

avoid allogenic blood has not been consistent– Best if blood pools in incision – effective for scoliosis surgery

• Craniosynostosis has very high allogenic transfusion rate– 9 mo of age, relatively large blood loss, difficult cell salvage

• Reducing Allogenic Blood Transfusions during Pediatric Cranial Vault Surgical Procedures: A Prospective Analysis of Blood Recycling Fearon,. Plast Reconstr Surg 2004;113:1126–30– Avg age 4 years. Avg surgery 196 min. 53% 1º, 47% repeat.– 60 patients (3 mo to 19 yrs). 5-900 mls blood salvaged. 18 of 60

(30%) received allogenic blood. No complications .

05/05/2010

Blood Conservation – Controlled ↓BP

• Controlled hypotension– mABP between 50 and 60 mm Hg– impaired oxygen delivery to tissues during hypotension are not

as significant in children compared with adults with preexisting atherosclerotic disease of the heart, brain, or kidney

– Contraindications: significant reduction in the availability of oxygen to the tissues (↓ SaO2, ↓ CO, ↓ Hb); or cardiac, cerebral, or renal disease; and increased intracranial pressure

• The effect of hypotensive anesthesia on blood loss and operative time during Le Fort I osteotomies. - J Oral Maxillofac Surg 2000– Twenty-three patients were randomized into normotensive or

hypotensive anesthesia. It reduced blood loss and improved the quality of the surgical field. It did not reduce operative time.

05/05/2010

Topical agents

• Fibrin sealant is prepared from two plasma-derived protein fractions:– a fibrinogen-rich concentrate– a thrombin concentrate

• formation of a fibrin clot that adheres to the application site and acts as a fluid-tight sealing agent able to stop bleeding

• product is derived from donor plasma– exposed to several viral inactivation steps

• solvent-detergent• Pasteurization• vapor-heat treatment• nanofiltration

05/05/2010

Temperature

• Neonates and infants at risk of hypothermia– immature thermoregulatory mechanism– relatively thin layer of subcutaneous brown fat for insulation– extensive superficial circulation that facilitates rapid dissipation

of heat from the body

• Hypothermia causes– platelet dysfunction– clotting factor enzyme dysfunction– Abnormal fibrinolytic activity

05/05/2010

Pediatric Transfusion – Summary

• Physiology• Transfusion reactions• Blood Conservation

– Multimodal approach– High initial hemoglobin and low target hemoglobin decreases

need or amount of transfusion– Study results have varied – patient population, surgical

procedure and anesthetic/conservation technique impact on success of a particular approach

05/05/2010