Saturday, 18 April 2015

Anaphylactic shock algorithm

IM Adrenaline 1:1000 1/2 ml (500mcg)
IV hydrocortisone 200mg
IV Clorphenamine 10mg

Hemorrhagic shock in injured patient

Initial paitent assessment


Is the patient in shock?

Reliance on BP alone may cause delay.
Compensatroy mechanisms may preclude a measurable fall in systolic bp until up to 30% of the patient’s blood volume is lost.

Pulse rate
Respiratory rate
Skin circulation
Pulse pressure

Tachycardia and cutaneous vasoconstriction (typical early physiologic responses to volume loss)

Any injured patient who is cool and has tachycardia is considered to be in shcok until proven otheriwse.

Elderly patients may not exhibit tachycardia
Limited cardiac response to catecholamine sitmulation
use of B bloers
Pacemaker

Normal hemaocrit does not exclude significant blood loss.

Base deficit and lactate levels are useful to determine presence and severity of shock.

What is the casue of hte shock state?


Haemorrhagic or

Non hemorrhagic

Cardiogenic
Cardiac injury, tamponade, air embolus, myocaridal infarction.
Investigations: ECG, CK, Echo, FAST.
Signs: Tachycardia, muffled heart sounds, and dilated engorged neck veins with ypotension resistant to fluid therapy.

Tension Pneumothorax

Mediastinal shift, impaired venous return, fall cardiac output.
Signs: Acute respiratory distress, subcutaneous emphysema, absent breath sounds, hyperresonance to percussion, tracheal shift.

Neurogenic
Intracranical injureis do not cause shock
Signs: hypotension without tachycarida or cutanrous vasoconstriction
should be treated first as hypovolemic shock, but failure to restor organ perfusion suggests either continuing hemorrhage or neurogenic shock.

Septic shock
might be confused with hypovolemic shock both present
tachycardia, cutanerous vasocontriction, impaired urinary output, decresased systolic pressure and narrow pulse pressure.

Haemorrhagic shock in injured patients.


Classification of haemorrhage

Class I
Individual who has donated a unit of blood.

Class II
uncomplicated hemorrhage, crystalloid fluid resuscitation is requried.

Class III
Complicated hemorrhage, at least crystalloid infusion is required and perhaps blood replacement

Class IV
preterminal event


Class I hemorrhage (15% blood volume loss)
750 ml
PR <100
BP Normal
PP Normal or increased
RR 14-20
UO > 30
CNS Slightly anxious
Fluid replacement Crystalloid


Class II hemorrhage (15-30% blood loss)
750-1500
PR 100-120
BP Normal
PP Decreased
RR 20-30
UO 20-30
CNS Mildly anxious
Fluid replacement Crystalloid

Class III (30-40% blood loss)
1500-2000
PR 120-140
BP Decreased
PP Decreased
RR 30-40
UO 5-15
CNS Anxious, confused
Fluid replacement Crystalloid and blood +_ SURGICAL INTERVENTION



Class IV (>40%)

>2000
PR >140
BP Decreased
PP Decreased
RR >35
UO Negligible
CNS confused, lethargic=
Fluid replacement Crystalloid and blood. + SURGICAL INTERVENTION

Initial management of haemorrhagic shock

What can I do about shock?

Stop bleeding and replace volume loss


ABCDEs
Vital signs, urinary output, and level of consciousness are essential


Airway and breathing

Establish a patent airway with adequate ventilation and oxygenation
Supplementary oxygen is supplied

Circulation - hemorrhage control

Controlling obvious hemorrhage
Obtaining adequate intravenous access
Assessing tissue perfusion

Bleeding from external wounds —— direct pressure

Rapid intravenous fluid infusion

Neurological exam
assess cerebral perfsuion
Exposure
Decompression of gastric dilatation
Urinary catheterisation

Vascular access
Two large caliber peripheral intravenous catheters
Fluid warmers and rapid infusion pumps are used in the presence of massive hemorrhage.
Forearms anticubital veins most desirable.
Central venous access (femoral, jugular, subclavian) if no peripheral access possible.
Blood drawn for type and crossmatch, lab analysis, toxicology, preganncy.
ABG
Chest xray document position of central line.

Initial fluid therapy

Warmed isotonic solutions.
Normal saline, ringer lactate
Alternative is hypertonic saline, although there is no evidence of sruvival advantage.

Initial warmed flid bolus is given as rapidly as possible 1-2 litres for adults and 20ml/kg for paediatric patients.

3-1 rule, each 1 ml of blood loss with 3 ml o fcrystalloid fluid.

monitor patient response
Urinary outpaut
Level of consciousness
Peripheral perfusion
blood pressure

Aware that fluid resuscitation is not substitute for definitive control of bleeding.

What is the patient’s response?

Good response

Return to normal blood pressure,
pulse pressure
pulse rate
Improvement in CVP status (if central line is in place)

Urine output (renal perfusion)

Urinary output
0.5ml/kg/hr in adults
1mg/kg/hr in paediatrics

Acid base balance
Respiratory alkalosis due to tachypnoea
mild metablic acidosis early phases
anaerobic metabolism due to inadequate tissue perfusion, production of lactic acid
persistent metabolic acidosis should be treated with fluid blood and operative intervention
(base deficit and lactate determines severity of shock)


Rapid response

respond rapidly and remain hemodynamically normal aftehr initial fluid bolus.
surgical consultation and evaluation are necessary

Transient response
show deterioration of perfusion indices as the intial fluids are slowed to maintenance levels. either on-going blood loss or inadequate resuscitation.
most of these patients lost 20-40% of their blood volume
continued fluid administratoin and initiation of blood transfusion is indicated.
rapid surgical intervention is needed

Minimal or no response

Immediate, definitive intervention

Remember nonhemorrhagic shock ( blunt caridac injury, cardiac tamponade, tension pneumothorax)

CVP monitoring and cardiac ultrasonography helps differentiate between the various causes of shock.

Crossmatched, type-specific and type o blood

Fully crossmatched blood is preferable, however it takes 1 hour.
Type specific blood can be provided within 10 minutes
Compatible with ABO and Rh blood types (preferred for transient responders)
Complete cross match should be performed
Type O paced cells are used if Type specific blood is not available
Rh negative preferred for females of childbearing age.

Warming fluids plasma and crystalloid

heat crystaloid to 39C before using it.
warmer or microwave oven (blood products cannot bewarmed in micrwave oven)

Autotransfusion
should be considered for any patient with a major hemothroax

Coagulopathy

PT, PTT, Platelets should be measured in the first hour
Transfusion of platelets, cryoprecipitate and FFP should be guided by coagulation parameters including fibrogen levels
consideration of early blood component therapy should be given to class IV hemorrhage pts.

Calcium administration
mostly not needed. maybe harmful


Special consdierations in the diagnosis and treatment of shock

Equating blood pressure with cardiac output
unrelated, an increase in peripheral resistance for example with vasopressor therapy with no change in caridac output results in increased blood pressure but no improvement in tissue perfusion or oxygenation.

Advanced age
Decrease in sympathetic activity, deficit in response to catecholamines
caridac complliance decresease
unable to increase hart rate or efficiency of contraction
atherosclerosis and occlusive disease makes vital organs sensitive to bp reduction
preexisting volume depletion (diuretic use, malnutrition)
b-blockers may mask tachycardia
consider early invasive monitoring
reduction in pulmonary compliance compounds cellular hypoxia
glomerular and tubular ageing

Athletes 
blood volume increase 15-20%
cardiac output sixfold
storke volume 50%
resting pulse 50
remarkable ability to compensate for blood loss


pregnancy
physioloigc hypervolemia, greater blood loss to manifest perfusion abnormalities

Medications
B blockers calcium channel blockers alters hemodynamic response to hemorrhage.
Insulin overdose
long term diuretic hypokalemia
NSAIDS platelet function

Hypothermia
unresponsive to fluid resuscitation
coagulopathy

Pacemaker
unable to respond to blood loss
CVP monitoring is invaluable








ABCD

Airway


Inspection (foreign bodies, facial, mandibular fractures)
Chin lift or jaw thrust maneuver
If patient communicates verbally, airway not likely to be in immediate jeopardy.
If GCS <8 they need definitive airway


Prevent excessive movement of spine.
Protect spine with immobilisation devices

Breathing and ventilation 

Chest exposed

Inspect
Auscultate
Palpated

Injuries that can impair ventilation include
Tension pneumothorax
flail chest and pulmonary contusion
massive hemothorax
open pneumothroax


Circulation with haemorrhage control 

Blood volume and cardiac output 

Hypotension must be considered hypovolemic in origin until proved otherwise
Clinically: Level of consciousness, skin colour, and pulse. (could be assessed within seconds)

(Elderly limited physiological reserve, Children have abundant reserve)



Level of consciousness:
blood loss, impaired cerebral perfusion, altered level of consciousness.

Skin colour:
Pink skin in face and extremities rarely has critical hypovolemia.
Ashen, gray facial skin, white extremities.

Pulse
Assess for quality rate and regularity.
Rapid thready pulse, is sign of hypovolemia.
Abscent central pulse necessitate immediae resuscitative action


Bleeding

External haemorrhage
manual pressure on the wound
Pneumatic splinting devices
Tourniquet
Hemostats

Disability

Rapid neurological evaluation
Level of consciousness
Pupillary size and reaction, lateralizing signs, and spinal cord injury.
GCS (best motor response)


Exposure

Complete exposure
Warm blankets
External warming device
IV fluids warmed
Warm room temperature


Resuscitation 


Airway

Jaw thrust or chin lift
If unconscious and no gag reflex then oropharyngeal airway can help temporarely (Guedel)
Intubation if not maintaining

Breathing/Ventilation/Oxygenation 

Intubate if compromised airway due to mechanical factors, ventilatory problems or unconscious.
Surgical airway if intubation not possible
Chest decompression immediately if tension pnumothorax is suspected

Suplemental oxygen
If not intubated should have mask-reservoir device to achieve optimal oxygenation.
Pulse oximeter to monitor

Circulation and bleeding control 

Two large caliber intravenous (IV) catheters shold be introduced.
Draw blood for type and crossmatch baseline hematologic studies including pregnancy test

Definitive control of hemorrhage is essential
Operation, angioembolization and pelvic stabilization.

IV fluid with crystaloids
1-2 litres of isotonic solution to acheive an appropriate resonse in the adult patient
shold be warmed
if unresponsive to bolus IV therapy, blood transfusion may be required.

Be aware of hypothermia.


Adjuncts to primary survey

ECG
Urinary catheter
gastric catheter
Ventilatory rate
ABG
Pulse oximetry
Blood pressure
X-ray examination


ECG
Tachycardia, AF, Premature ventricular contractions, ST changes can indicate blunt caridac injury.
PEA can indicated cardiac tamponade, tension pneumothorax, profound hypovolemia.
Bradycardia, aberrant conduction and premature beats indicated hypoxia and hypoperfusion

Urinary catheters 
Urine output
contraindicated in suspected urethral injury (blood at meatus, perineal ecchymosis, blood scrotum, high riding prostate, pelvic fracture), retrograde urethrogram should be done if suspected before insertion of catheter.

Gastric catheters 
Reduce stomach distention and decrease risk of aspiration

Other monitoring

Ventilatory rate and ABG
Adequacy of respiration

Pulse oximetry 
Measures the oxygen saturation of haemoglobin, but not the partial pressure of oxygen. value should be compared with ABG reading.

Blood pressure 

X-ray examination and diagnostic studies. 

AP chest and pelvic films.
FAST and DPL are useful for detection of occult intraabdominal blood.


Secondary survey