Critical Care

Question 1

For what patients would intensive care be appropriate for?

Answer 1

• Patients requiring or likely to require advanced respiratory support alone
• Patients requiring support of two or more organs
• Patients with chronic impairments to their daily activities and who require support for an acute reversible failure of another system

Question 2

For what patients would high dependency care be appropriate for?

Answer 2

• Patients requiring support for a single failing organ system (not respiratory)
• Patients that would benefit from detailed observation or monitoring
• Patients no longer needing intensive care but not yet wll enough to return to a general ward
• Post-operative patients who need dose monitoring for longer than a few hours

Question 3

What are the ideal measurements that should be seen in patients who are seriously ill?

Answer 3

HR - 70
BP - 120/80
RR - 14
SpO2 - 98%
Temp - 37°C
Concious
Passing urine
Acid-base normal
Pain free

Question 4

Describe the APACHEII scoring system

Answer 4

Acute Physiology and Chronic Health Evalutation

A score given to ICU patients within 24 hours of admission, between 0-71. It is based on 12 physiological measurements as well as age, previous health status etc. It is used to determine the patient’s severity of illness and risk of death

Question 5

Describe the SOFA scoring system

Answer 5

Sequential Organ Failure Assessment

This scoring system uses six different criteria, each scored between 1 and 4;

• Resp (PaO2/FiO2)
• CNS (GCS)
• CVS (MAP)
• Liver (Billirubin)
• Coagulation (platelets)
• Renal (Creatinine or urine output)

Question 6

Define SIRS

Answer 6

Systemic Inflammatory Response Syndrome

• Temp 38°C
• HR >90bpm
• RR >20/min
• WCC >12000/mm or 10% immature neutrophils

Question 7

Define septic shock

Answer 7

Severe sepsis with hypotension that is not responding to antihypertensive agents or fluid challenges. This leads to inadequate tissue and organ perfusion and a rising lactic acidosis

Question 8

Describe the stages of signs and symptoms of sepsis

Answer 8

Early - Classically unwell e.g. hot, sweaty, flushed and general malaise
Established - Patient has become more ill so has warm peripheries, pyrexia and a bounding pulse. Will also have a high CO and vasodilation
Late - Cold peripheries and mottled skin will also have a low CO

Question 9

Describe the pathophysiology of sepsis

Answer 9

1) Microorganisms enter the blood
2) Toxins are released
3) Release of endogenous mediators and activation of the inflammatory and immune responses
4) Profound physiological systemic effects and organ dysfunction/failure

Question 10

Describe the vasomotor pathophysiological responses seen in sepsis

Answer 10

1) Bacteraemia and endotoxaemia
2) Induction of nitric oxide synthase
3) Nitric oxide mediated arterial vasodilation
4) Poor venous return to the heart
5) Baroreceptors alert the CNS
6) The CVS increases vasoconstriction
7) The RAAS is upregulated to conserve water and sodium

Question 11

Describe the three effects of nitric oxide synthase

Answer 11

Regionally - Body distributes blood flow to the vital organs
Microvascularly - Erythrocytes become less deformable so the tissue cannot extract oxygen and capillaries shut down
Centrally - Change in systolic and diastolic ventricular funciton

Question 12

Describe the effects of capillary leaks in sepsis on the following organ systems;

• GI
• CNS and PNS
• Liver
• MSK

Answer 12

GI - Widening of the gap junctions allows bacterial translocation from the gut lumen to the blood
CNS/PNS - Disruption of the BBB which leads to confusion. There is also peripheral axon degeneration
Liver - May perpetuate sepsis
MSK - Breakdown of muscle to produce proteins

Question 13

Describe the two main types of β receptor and their effects

Answer 13

β1 - 
   - Inotropy (increases myocardial contractility)
   - Chronotropy (increases rate)
β2 - 
   - Vasodilation

Question 14

Describe the use of dopamine as a catecholamine

Answer 14

A precursor to noradrenaline that increases urine output but is hardly ever used as it doesnt improve outcome

Question 15

Describe the use of dobutamine as a catecholamine

Answer 15

Predominantly acts on β1 and β2 receptors;
- Inotropy - Strong
- Chronotropy - Weak
- Vasoconstriction - None
Always increases CO but the effect on BP is variable

Question 16

Describe the use of norepinephrine as a cetacholamine

Answer 16

Potent α-agonist with some β-activity;
- Inortropy - Weak
- Chronotropy - Very weak
- Vasoconstriction - Very strong
Reliably increases BP

Question 17

Describe the use of epinephrine as a catecholamine

Answer 17

• Increase CO and BP reliably

- High doses - Increases pulmonary vascular pressures (problematic)

Question 18

Describe the use of phosphodiesterase inhibitors as catecholamines

Answer 18

Work by a different method to other inotropes so can be used if other inotropes fail

Question 19

Describe the use of vasopressin as a catecholamine

Answer 19

Works on vasopressin in the vascular smooth muscle and renal collecting system to increase vascular tone and sensitise the blood vessels to noradrenaline

Question 20

How do we measure tissue oxygenation in ICU?

Answer 20

Measured via mixed venous oxygenation

• Target in ICU = SVO2 of 70%
• Below 70% = Medical emergency
• Too high = Organs are failing and not using oxygen

Question 21

Describe Haemofiltration as a form of RRT

Answer 21

In haemofiltration/ultrofiltration the blood passes across a membrane which allows blood cells etc. to stay in the patient’s circulation but water and electrolytes leave, along with waste products. Fluid is then replaced with a normal level of electrolytes

Question 22

Describe Haemodialysis as a form of RRT

Answer 22

In haemodialysis/tubular diffusion the blood leaves the patient and passes through a dialysis machine which contains liquid with a normal level of electrolytes. The electrolytes, waste products etc. move across a membrane down their concentration gradient

Question 23

Describe Haemodiofiltration as a form of RRT

Answer 23

This method is the same as haemofiltration, however the pump that moves fluid back into the body has a small amount of dialysis fluid

Question 24

What is Diffuse Alveolar Damage?

Answer 24

A non-specific pattern of acute lung injury caused by a variety of noxious agents

Question 25

Describe the three phases of DAD

Answer 25

• Exudative Phase - (1-7 days) Leakage of blood and fluid into the lungs
• Regenerative Phase - (3-10 days) Type 2 pneumocytes replace type 1 pneumocytes. They may grow over the hyaline membrane instead of under. This permanently thickens the membrane and may even occlude the opening of the alveoli
• Repair Phase - (>1-2 weeks) Lung tissue repairs however myofibroblasts contract and cause shrinkage of the lung

Question 26

Describe the criteria for diagnosing ARDS

Answer 26

Timing - Within one week of a known clinical insult or new or worsening respiratory symptoms
Chest Imaging - Bilateral opacities, not fully explained by effusions, lobar/lung collapse or nodules
Origin of Oedema - Respiratory failure not fully explained by cardiac failure or fluid overload
Oxygenation - Mild = 200mmHg
Moderate = 100mmHg
Severe = <100mmHg

Question 27

What are the three main goals for the management of ARDS?

Answer 27

1) Maintain tissue oxygenation
2) Minimise harm
3) Support other failing organs

Question 28

For what patients is ventilatory support appropriate?

Answer 28

• Unresponsive hypoxemic
• Exhaustion
• Severe hypercapnia

Question 29

What are the four possible causes for respiratory failure?

Answer 29

• Shunting
• V/Q mismatch
• Reduction in gas diffusion
• Increased dead space