Critical Care Flashcards
Define shock
Clinical syndrome caused by inadequate tissue perfusion and oxygenation leading to abnormal metabolic function
Name the six types of shock
Cardiogenic Hypovolaemic Obstructive Septic Anaphylactic Neurogenic
Why should colloids be stopped in anaphylactic shock?
Colloids may be the cause of anaphylaxis
How is Systemic Inflammatory Response Syndrome (SIRS) defined?
Present if 2 or more of the following: HR >90 Temp <36 or >38.3 RR >20 or PaCO2 <4.3kPa WCC <4 or >12 x 10 to the power of 9/l
How is sepsis defined?
SIRS plus known or suspected infection
How is severe sepsis defined?
sepsis + signs of hypoperfusion or organ failure including decreased urine output, elevated urea or creatinine, abnormal LFTs, coagulation disturbance, hypoxia or ARDs or a raised serum lactate
Define septic shock
Severe sepsis with hypotension (systolic BP <90 or MAP <60) despite adequate fluid resuscitation or the requirement for vasopressors/inotropes to maintain blood pressure
What is the treatment given for sepsis?
BUFALO Blood cultures + septic screen Urine output – monitor hourly Fluid resuscitation Antibiotics IV – see microbiology guideline Lactate measurement Oxygen to correct hypoxia
What are the clinical signs of shock?
- Systolic BP <90mmHg (or a 30mm Hg fall in baseline BP)
- Lactate >3 mmol/L
- Base excess <4mEq/L
- Reduced capillary refill time
If blood pressure is unrecordable in suspected shock what action should be taken?
Call the cardiac arrest team
What is the treatment for anaphylactic shock?
- A-E assessment
- Adrenaline 1:1000 solution, 0.5ml (0.5mg) intramuscular
Repeat after 5 mins if no improvement - IV infusion 1L 0.9% saline STAT
- Chlorphenamine (antihystamine 10mg slow IV
- Hydrocortisone 200mg slow IV
What is MAP?
Mean arterial pressure = Cardiac output x Systemic vascular resistance
What assessments should be regularly repeated in assessing perfusion?
Heart rate and respiratory rate trends
Urine output
Repeated ABG and lactate
Conscious level monitoring
How do inotropes work?
Inotropes increase the contractility of the heart (and often its rate as well) usually by acting on Beta receptors (increase cardiac output)
How do vasopressors work?
Vasopressors cause vasoconstriction of the peripheral vasculature by acting on alpha receptors (increase systemic vascular resistance)
If a patient with suspected shock presents as cool and pale what are the most likely causes of shock?
Hypovolaemic (hamorrhage)
Cardiogenic (MI, tamponade, arrhythmias)
How is hypovolaemic shock treated?
Identify and treat underlying cause (stop bleeding)
Raise legs
Give fluid bolus 1L 0.9% saline STAT
Crossmatch and group and save
Aim for HR <100 BP >90 and urine output >0.5mL/kg/hr
A patient in suspected shocks presents as warm, clammy, vasodilated. What sort of shock could this be?
Distributive:
Sepsis
Anaphylaxis
Neurogenic
For which type of shock are inotropes recommended?
Cardiogenic
Name three commonly used inotropes?
Dobutamine
Adrenaline
Ephidrine
Name two commonly used vasopressors?
Noradrenaline
Metaraminol
What is the average fluid requirement of a normal person?
Approximately 2500ml over 24 hours or 25-30ml/kg/24hr
What does normal fluid loss occur via?
Urine (1500ml)
Stool (200ml)
Insensible losses, sweat, evaporative water from respiratory tract (800ml)
How will a patient that is underfilled (dry) present?
- Tachycardia
- Postural drop in BP
- Increased cap refill time
- Decreased urine output (>0.5ml/kg/hr)
- Cool peripheries
- Dry mucous membranes
- Decreased skin turgor
- Sunken eyes
How will a patient that is overfilled present?
- Increased JVP
- Pitting oedema of sacrum, ankles or even legs and abdomen
- Tachypnoea
- Bibasal crepitation’s
- Pulmonary oedema on CXR
How much Na+ and K+ is required per 24 hours
100mmol Na+
70mmol K+
What sort of patients would require higher fluid requirements?
Those with excess loss, e.g vomiting, diarrhea, drains, fever, (sweating).
Those with decreased demand, e.g. elderly/frail, low BMI, heart problems, renal failure
How much bodily fluid does a 70Kg man have
42L (60% body weight)
What proportion of bodily fluids are intracellular and extracellular?
2/3rds intracellular (28L)
1/3rd extracellular (14L)
How much blood does a 70kg man have on average?
1/3rd of their extracellular compartment (5L)
What are third space fluids/fluid sequestration?
inflammation and injury cause capillary permeability to increase so that fluid and protein leak from the blood vessels causing oedema
When is fluid sequestration most commonly seen?
Pancreatitis
Sepsis
Post major operations
Describe a fluid challenge
A bolus of crystalloid 0.9% saline 500ml (250ml if frail or heart problems, 10ml/kg in children) given over <15 minutes. Reassess immediately.
What is the maximum safe rate if potassium administration outside of HDU/ICU?
10mmol/hr
What is the daily glucose requirement?
50-100mg/24hr
How much glucose is in 500 ml 5% glucose
5g/100ml so 25g in 500ml 5% glucose
Why is dextrose (5% glucose) useless for fluid resuscitation?
Contains a small amount of glucose which is quickly metabolized leaving only water. Water then rapidly equilibriates throughout all fluid compartments.providing hydration but not resuscitation.
