One night in A+E

Topics for discussion Acid Base Balance and Disorders Arterial Blood Gas Measurement Lung volumes Cardiac Cycle

Objectives Understand the basic principles of Acid Base Balance Use a systematic approach to interpret ABGs Interpret and name lung volumes on a graph Understand the difference between Obstructive and Restrictive patterns of lung disease Be able to name and understand the curves on a cardiac cycle diagram

CSE CSE

You are a junior doctor on your very first day working in the A&E department at the Royal Free. 2021??

Them Values pH PaCO 2 Normal range: kPa or mmHg HCO 3 - Normal range: mmol/L

What is an “arterial blood gas” (ABG)? What does it measure? Turn to your colleague…

Volatile acid Non volatile acids? CO 2 + H 2 O H 2 CO 3 H + + HCO3 -

Buffering

Compensation CO 2 + H 2 O H 2 CO 3 H + + HCO3 -

With this background knowledge in mind, you proceed to meet your first patient!

Mr. Jones You meet a 60-year-old male with a history of chronic obstructive pulmonary disease. He is obviously unwell, with severe shortness of breath, pyrexia (fever) and productive cough. His ABGs are shown below: pH7.20 PaCO 2 9.3kPa (or 70 mmHg) HCO mmol/L pH PaCO kPa or mmHg HCO mmol/L

How not to kill someone – an approach to ABGs pO2 (determine oxygenation) pH (acidosis/alkalosis) PaCO2 HCO3- What’s the primary disturbance? Is there any compensation? Is it appropriate?

Mr. Jones You meet a 60-year-old male with a history of chronic obstructive pulmonary disease. He is obviously unwell, with severe shortness of breath, pyrexia (fever) and productive cough. His ABGs are shown below: pH7.20 PaCO 2 9.3kPa (or 70 mmHg) HCO mmol/L pH PaCO kPa or mmHg HCO mmol/L

Jim Your next patient is an 18 year-old male. He has been vomiting for the last 24 hours and feels unwell. His ABGs are shown below: pH7.49 PaCO 2 6.3kPa (or 47 mmHg) HCO mmol/L pH PaCO kPa or mmHg HCO mmol/L

Ben You next meet an 8 year-old male who appears lethargic and has a strangely “fruity” smell to his breath. He has a previous history of polyuria (increased frequency and volume of urination), polydipsia (increased thirst) and weight loss. pH7.30 PaCO 2 3.3kPa (or 25 mmHg) HCO mmol/L pH PaCO kPa or mmHg HCO mmol/L

Ronald Your next patient is a 20 year-old with Duchenne muscular dystrophy admitted with urinary tract infection (UTI). He has a temperature of 39 o C, feels warm and peripherally vasodilated with a blood pressure of 90/60. pH7.28 PaCO 2 6.3kPa (or 47 mmHg) HCO mmol/L pH PaCO kPa or mmHg HCO mmol/L

As you begin to rest your heavy head… CSE CSE

OMG The paramedics have brought in a 50 year-old man suspected of having an upper GI bleed. His BP is 90/40. pH7.30 PaCO 2 3.3kPa (or 25 mmHg) HCO mmol/L Lactate5 mmol/L (normal: ) pH PaCO kPa or mmHg) HCO 3 - About 24mmol/L (Normal range: mmol/L)

On your way out at 8am, you decide to revise some Year 1 physiology..

Obstructive almostadoctor.co.uk

Restrictive almostadoctor.co.uk

Any Questions?