ACUTE HAEMORRHAGE Flashcards
Calculate cardiac output?
BP/systemic vascular resistance
HR x stroke volume
What are the 3 main pathophysiologies behind shock?
Cardiogenic - decreased CO e.g. MI, PE, tamponade
Systemic vascular - increased systemic vascular resistance e.g. sepsis, anaphylaxis, spinal shock
Reduced stroke volume caused by fluid loss e.g. haemorrhage, D&V
How can we use the JVP to work out the cause of shock?
If it’s high with bibasal creptiattions and pt is cold = likely carcinogenic
If low with postural hypotension and cold = likely hypovolaemia
If low with a bounding pulse and warm = likely septic
What is the definition of shock clinically?
Persistently low BP systolic <90 (or a reduction in 30mmHg if hypertensive usually) AND altered end-organ function e.g. oliguria or confusion
How does haemorrhage present?
Pallor
Tachycardia
Clammy
Hypotension - this is actually a late sign of shock!
May be obvious source of bleeding
May have cullens sign of gray turner sign
What is cullens sign and what can it indicate?
a physical exam finding of ecchymoses, or bruising, around the umbilicus.
Caused by intrabdominal haemorrhage - most commonly pancreatitis
What is grey turners sign and what can it indicate?
ecchymosis or discoloration of the flank
A sign of intra- or retroperitoneal haemorrhage. Most commonly pancreatitis
Outline the response of the heart rate in shock?
Biphasic response to volume loss - initial vasoconstriction and tachycardia followed by a bradycardia
(This is why absence of tachycardia does not exclude a life threatening haemorrhage)
Examinations you should do if you suspect a haemorrhage?
Inspect pt for obvious sources of bleeding
Assess abdomen and flanks
Do a PR
Assess long bones and pelvis
Class 1 haemorrhage signs?
Blood loss <750ml or <15%
HR <100
Normotensive
RR 14-20
Urine output >30ml/hr
Class 2 haemorrhage signs?
Blood loss 750-1500ml or 15-30%
HR 100-120
Normotensive
RR 20-30
Urine output 20-30ml/hr
Class 3 haemorrhage signs?
Blood loss 1500-2000ml or 30-40%
HR 120-140
Decreased BP
RR 30-40
Urine output 5-20ml/hr
Class 4 haemorrhage signs?
Blood loss >2000ml or >40%
HR >140
Decreased BP
RR >40
Urine output <5ml/hr
Which groups of pt should you have a very low threshold for suspecting life-threatening haemorrhage?
Pregnant
Trauma cases
Recent surgical procedures
GI bleeds
?ruptured AAA
Pt on anticoagulants, who have hypertension or liver failure
What are the common causes of life threatening bleeds?
Scalp and external causes
Abdomen
Pelvis
Chest
Long bones
Retroperitoneal space
What is the “lethal triad” in acute haemorrhage in trauma patients?
Coagulopathy
Hyperthermia
Acidosis
These 3 things are irreversible and have a grave prognosis as the latter 2 both synergistically affect coagulopathy
Outline how each aspect of the lethal triad impact prognosis in acute haemorrhage?
Hypothermia - impairs platelet function and enzymatic function in the clotting cascade
Acidosis - impairs clotting
Coagulopathy - impaired ability of the coagulation system to synthesize blood clots
What can cause hypothermia in trauma patients?
Haemorrhagic shock
TBI
Alcohol intoxication impairing the ability to regulate core temperature
Extremes of age
Prolonged exposure to environment
Those with severe burns
With medical conditions such as diabetes and thyroid disease
What causes acidosis in trauma patient as?
Poor perfusion to tissues causing lactic acidosis - due to anaemia from acute blood loss, peripheral vasoconstriction in response to hypothermia and blood loss etc
Excessive resuscitation using unbalanced Crystalloids solutions can also cause acidosis
A pt may also have respiratory acidosis due to hypoventilation e.g. resp depression narcotic use, TBI, flail chest, COPD
How do we prevent hypothermia in trauma pts?
Limit exposure
Remove wet clothing
Using warming blankets
Use warm fluids and blood products
Keep room warm
How do we prevent acidosis in trauma patients?
Haemostatic resuscitation and limit crstalloid infusions as much as possible!
Monitor and maximise oxygenation to avoid additional respiratory acidosis
Treat causes of hypoventilation to prevent respiratory acidosis
Measure lactate
How do we manage/prevent a coagulopathy in trauma patients?
Limit use of crystalloids or unbalanced blood products which could cause a dilutional coagulopathy
Identify high-risk patients with a baseline coagulopathy due to meds or pre-existing medical conditions
Administer TXA to prevent clot breakdown
Investigtaions for haemorrhage secondary to trauma?
Establish IV access with 2 wide bore cannulas
Bloods - FBC, U&Es, LFTs, Coag study, ABG/VBG, group and save, emergency cross-match
CT angiography
Pan-CT
FAST USS
What is the gold standard investigation for finding the source of a bleed in acute haemorrhage?
CT angiography
When is FAST ultrasound used in trauma cases?
When suspecting trauma that could cause hemoperitoneum and hemopericardium
Good when CT is not possible immediately
What is a group & save?
Determines the patient’s blood group is.e. ABO and RhD and screens the blood for any atypical antibodies
The process takes around 40 minutes and no blood is issued.
What is a crossmatch?
When you physically mix the patient’s blood with the donors blood to check for immune reactions
This process taes about 40 minutes but on top of a G&S which must be done before!
When would you do group & save and when would you do a crossmatch?
Group & save for when blood loss is not anticipated by blood may be required if greater blood loss than anticipated. Usually patients undergoing planned surgeries that may require transfusion, ideally have samples for group and save taken at preadmission clinics.
Cross match is done when blood loss is anticipated
Definition of major haemorrhage?
The loss of 1 blood volume (70ml/kg) in 24 hours
OR
The loss of 50% of the circulating blood within 3 hours
OR
The loss of blood at a rate >150ml/min
Normal blood volume in adults?
70ml/kg
Principles of haemorrhage control?
Involve specialities early on
Control the bleed:
Direct pressure, tourniquet, pelvic binder etc
Reversal of any anticoagyulkants
Give tranexamic acid
Replace lost blood volume:
Replace with 1:1 ratio of units of plasma:red cells
Use the permissive hypotension approach
Avoid the lethal triad of hypothermia - keep pt warm, maximise oxygenation and treat hypoventilation, avoid unbalanced blood products and Crystalloids
What is the permissive hypotension approach?
Maintaining a blood pressure lower than physiologic levels in a patient that has suffered from hemorrhagic blood loss.
Aim for systolic 80-90
This is to maintain adequate vasoconstriction, organ perfusion, and prevent an undesired coagulopathy during initial fluid resuscitation
What is the minimal volume normotensive approach?
A method that looks at the mean arterial pressure and has a target MAP of 65mmHg.
If MAP falls below this then fluids/blood is given and if MAP rises above this the fentanyl can be givento drop the MAP again.
The aim is to prevent major haemorrhage whilst also maintains adequate perfusion
Why do we no longer do the traditional fluid resuscitation with 1-2L of crystalloids fluids in trauma pt with ?acute haemorrhage?
This can cause a dilutional coagulopathy, impaired oxygen delivery due to dilutional anaemia, hypothermia, worsening metabolic acidosis and clot dislodgement. It can also cause further haemorrhage from elevated blood pressure
Why can improper administration of crystalloids cause hyperchloremic metabolic acidosis?
As normal saline has a higher concentration of Cl- than blood
What are packed red cells stored in?
Sodium citrate, an anticoagulant solution, which functions by binding calcium
Whats the threshold for giving packed red cells?
Hb of 70 or 80 in ACS
How fast must packed red cells be transfused?
Must be completed within 4 hours from the time the unit is removed from the blood bank
How much will 1 unit of red cells increase the Hb by?
By 10g/L on average
Whats the target Hb when giving packed red cells?
70-90
80-100 if ACS
What is in fresh frozen plasma?
It contains all of the clotting factors
What is the thawing time for FFP?
20 minutes
What is the universal donor for FFP?
AB
Over what time is FFP given?
Over 30-60 minutes but must be used within 4 hours of removal from the blood bank
What is the standard adult dose for FFP?
15ml/kg which is 4 units
When is FFP indicated?
most suited for ‘clinically significant’ but without ‘major haemorrhage’ in patients with a PTratio or APTT ratio > 1.5
Storage requirements for platelets?
Stored at 22 degrees for 3-5 days so short supply
Threshold for giving platelet transfusion?
30x10^9 if clinically significant bleeding
100x10^9 if severe bleeding or bleeding at critical sites e.g. CNS
Target for platelets whilst giving platelet transfusion?
100x10^9
Which blood product has the highest risk of bacterial contamination?
Platelets
How fast should platelets be given?
Over 30 minutes and must be started within 30 minutes of removal from the lab
Which blood product does not need to be ABO comparable?
Platelets
What does cryoprecipitate contain?
Fibrinogen
Factor 8
Von WIllebrand factor
Factor 13
When is cryoprecipitate most suitable for?
Significant haemorrhage if fibrinogen <1.5 and uncontrolled bleeding due to haemophilia
How is cryoprecipitate made?
produced by further processing of Fresh Frozen Plasma (FFP).
Over what time is cryoprecipitate given?
15-20 mins
Who should recieve CMV-negative blood?
Pregnant women
Intrauterine transfusion
Neonates
Who should receive irradiated blood products and why?
Used to reduce the risk of graft vs host disease inat risk populations e.g. those receiving blood from first/second-degree family members, Hodgkin lymphoma, recent haematopoeitic stem cell transplants, after anti-thymocyte globulin or alematuzumab therapy, those receiving purine analogues as chemo and those with intrauterine transfuses
Observations during a blood transfusion?
Vitals must be recorded within 1 hour of transfusion. Start time
15 mins after start
1 hour after start
Within 1 hour of completion time
Which cannulas must blood products be administered through and why?
Green or grey cannulas
Otherwise the cells haemolyse due to sheering forces on the narrow tube
Before asking for a blood product what must you make sure is done?
Correct identification wrist band must be in place
Observations must be recorded
Verbal consent must be gained
Product must be prescribed
A patent green or grey cannula must be in place
There must be enough stafff members to monitor the pt
How many qualified staff members must check the blood product before administration?
2
What is SHOT?
Serious Hazards Of Transfusion
This is the UK’s leading haemovigilance scheme for adverse events and reactions in blood transfusions from all healthcare organisations. They produce recommendations to improve pt safety in annual reports
What are the SHOT 10 steps to transfusion?
Decision to transfuse and consenting of pt
Request
Sample taking
Sample and request receipt
Testing
Component selection
Component labelling
Component collection
Prescription
Administration and monitoring for reactions + documentation
Complications of massive haemorrhage?
Hypothermia
Hypocalcaemia
Hyperkalaemia
Delayed type transfusion reactions
TRALI
TACO
Coagulopathy
Why can blood products cause hypocalcaemia?
FFP and platelets contain sodium citrate which can chelate calcium
Why can blood products cause hyperkalaemia?
Due to the (inevitable) partial haemolysis of the red blood cells and the resultant release of intracellular potassium
What is the leading cause of transfusion-related deaths?
TRALI
Which blood product has the greatest risk of TRALI?
Plasma components due to leukocyte antibodies causing aggregation and degdranulation of the leukocytes in the lung tissues
How do blood products affect coagulopathy?
Clotting abnormalities can occur due to a dilution effect, as the packed red cells transfused do not contain any platelets or clotting factors. Specific conditions like trauma also in themselves can cause coagulopathy.
To reduce the risk of any clotting impairment, fresh frozen plasma and platelets should be administered concurrently, typically done for patients receiving more than 4 units RBCs
Management of a major bleed whilst on warfarin?
Stop warfarin
IV vitamin K
Prothrombin complex
Management of minor bleeding and an INR >8 whilst on warfarin
Stop warfarin
IV vitamin K
Restart warfarin when INR <5
Management of no bleeding and an INR >8 whilst on warfarin
Stop warfarin
Oral vitamin K
Restart when INR <5
Management of minor bleeding and an INR 5-8 whilst on warfarin
Stop warfarin
IV vitamin K
Restart warfarin when INR <5
Management of no bleeding and an INR 5-8 whilst on warfarin
Withhold 1-2 doses of warfarin and reduce the subsequent maintenance dose
Rules for pts on warfarin when they have a planned surgery?
Stop warfarin 5 days before surgery
Oral vit K day before surgery if INR >=1.5
Rules for pts on warfarin when they have a planned surgery but they are considered high risk of VTE?
Warfarin stopped 5 days before surgery and oral vit K given the day before surgery if INR >=1.5
May require interim therapy with LMWh but this must be stopped at least 24 hours before surgery
Rules for pts on warfarin when they have an emergency surgery?
If the surg can be delayed 6-12 hours then give IV vitamin K
If the surgery cannot be eluded then give prothrombin complex, IV vit K and check INR before surgery
Rules for pts on warfarin when they have an emergency surgery?
If the surgery can be delayed 6-12 hours then give IV vit K
If surgery cannot be delayed then give prothrombin complex, IV vit K and check INR before surgery
What drug is used to reverse dabigatran?
Idarucizumab
What drug is used to reverse apixaban?
Andexanet Alfa
What drug is used to reverse rivaroxaban?
Andexanet Alfa
Why can blood transfusions cause hypothermia?
As blood products are thawed from frozen and then kept at cool temperatures, they may not be up to body temperature by time of transfusion, especially in a major haemorrhage protocol scenario.
Rapid transfusion of these products can lead to a drop in the patient’s core temperature, hence regular monitoring of core body temperature is always required during a blood product transfusion.
What are the acute transfusion complications?
Acute haemolytic reaction
Transfusion associated circulatory overload
Transfusion related acute lung injury
Mild allergic reaction
Non-haemolytic febrile reactions
Anaphylaxis
Infective or bacterial shock
What are the delayed transfusion complications?
Infections e.g. hep B, HIV, syphilis
Graft vs host disease
Iron overload if repeated transfusions
What causes acute haemolytic reactions to blood transfusions?
ABO-incomparable blood e.g. giving wrong blood type - donor red cel;s are destroyed by the recipients pre-formed antibodies = haemolysis
How does acute haemolytic reaction present?
Usually within the first minutes of the start of the transfusion…
Fever
Abdominal and chest pain
Hypotension
May be haemoglobinuria from rapid haemolysis
Management of acute haemolytic reactions?
Stop transfusion
Conform diagnosis - check identity of pt, blood product etc & send blood for direct Coombs testing and repeat typing/cross-matching
Supportive care e.g. generous fluid resuscitation
What causes transfusion associated circulatory overload?
Excessive rate of transitions on pre-existing HF
Presentation of transfusion associated circulatory overload?
Pulmonary oedema
Hypertension
Management of TACO?
Urgent CXR
Slow or stop transfusion
Consider if loop diuretic
Oxygen if required
Pts at risk of overload can be prescribed 20mg furosemide prophylactically during the transfusion to prevent this
What causes transfusion-related acute lung injury?
Non-cardiogenic pulmonary oedema thought to be secondary to increased vascular permeability caused by host neutrophils that become activated by substances in donated blood
A type of ARDS that has a high mortality
Symptoms of TRALI?
Within 6 hours of transfusion…
Hypoxia
Fever
Hypotension
Management of TRALI?
Stop transfusion
CXR - will show pulmonary infiltrates
Oxygen and supportive care
Get specialist and ICU input urgently
What causes non-haemolytic febrile reactions?
antibodies reacting with white cell fragments in the blood product and cytokines that have leaked from the blood cell during storage
Often the result of sensitisation by previous pregnancies or transfusions
Presentation of non-haemolytic febrile reactions?
Fever
Chills
Which blood products cause non-haemolytic febrile reactions?
Platelet 10-30%
RC - 1-2%
Management of non-haemolytic febrile reactions?
Slow or stop the transfusion
Paracetamol
Monitor
Presentation of a minor allergic reaction to transfusion?
Pruritus
Urticaria
Management of a minor allergic reaction?
Temporarily stop the transfusion
Antihistamine
Monitor
What can cause anaphylaxis from a blood transfusion?
Can be caused by patients with IgA deficiency who have anti-IgA antibodies
Presentation of anaphylaxis from a blood transfusion?
Within minutes of staring the transfusion hypotension, dyspnoea, wheezing, stridor, angioedema.
Management of anaphylaxis from a blood transition?
Stop transfusion
IM Adrenaline 0.5ml 1 in 1000
ABC support
Complications of acute haemolytic transfusion reactions?
DIC
Renal failure
What criteria is used for diagnosis of graft vs host disease?
Billingham criteria
What is the Billingham criteria?
3 criteria for diagnosis of GVHD:
The transplanted tissue contains immunologically functioning cells
The recipient and donor are immunologically different
The recipient is immunocompromised
When might transfusion cause GVHD?
Very rarely
In immunocompromised pt
