TRAINEE WORKBOOK� PACU Breathing Learning and Teaching Resource

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Contents

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• Theory and practice of breathing management. Exercises and questions to help you develop your knowledge and skills of airway management.

• Exercises in this workbook match the content in the competencies and power point presentations.

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• There are some clinical scenarios to help consolidate learning.

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• Please print out the slides and keep them in a folder to complete.

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Breathing : Theory & Practice

This section is divided up into the following sections:

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1. Basic sciences.

2. Anaesthesia and Surgery.

3. Breathing assessment.

4. Breathing management [including Specific Complications].

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• Each section corresponds to the competency, power point presentation and additional notes for all the above elements.

1. Basic Sciences

Metabolism

Oxygen

Body cell

Carbon Dioxide

Explain the role of

oxygen and carbon dioxide

in cell metabolism

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What happens if the cell

does not receive oxygen?

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What happens if the body

does not excrete carbon

dioxide?

Hyper : Hypocarbia?

Fill in the blanks in the above grid with the alternatives given in

the first column. An example is given.

Airway and Lungs : Label diagram

• Nasal cavity
• Pharynx
• Epiglottis
• Larynx
• Apex of right lung
• Base of left lung
• Parietal pleura
• Visceral pleura
• Trachea
• Left primary bronchus
• Left secondary bronchus
• Alveoli
• Ribs
• Diaphragm
• Oesophagus

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Position of the lungs

• The lungs lie proximal to the heart : why is this important?

The airway tree

State whether the following airway

sections contain cartilage / smooth muscle:

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Trachea :

Bronchus :

Bronchioles :

Terminal Bronchioles :

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What is the function of cartilage?

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Smooth muscle can dilate or contract

affecting the lumen of the airway

What enervates this action?

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In peri-anaesthesia clinical practice what

may cause bronchospasm? How is it treated?

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The Alveoli

The alveoli are the terminal air sacs.

• How many alveoli are there in the lungs?

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• What is the function of the alveoli?

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• The surface area of the alveoli if stretched out would cover half a tennis court. What do we mean by surface area? Why is this important for the exchange of gases?

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• What is surfactant? What is it’s function?

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• How may prolonged surgery & ventilation affect the alveoli?

Pulmonary blood flow

Put the following in order to follow the flow of blood through the right heart, lungs and systemic circulation:

1. Pulmonary artery
2. Right atrium
3. Lungs
4. Aorta
5. Pulmonary vein
6. Body tissues
7. Left ventricle
8. Right ventricle
9. Left atrium

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• What is the only artery in the body which carries deoxygenated blood?

Pulmonary capillaries

• What is the purpose of the pulmonary

capillary network?

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• What do you understand by the V/Q ratio?

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• How does prolonged surgery affect the V/Q match?

Alveolar-Capillary junction

Describe the alveolar-capillary junction

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How does this ‘design’ facilitate gas exchange?

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Gases always move from an area of high to

low pressure…until equilibrium reached

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How does this explain the transfer of gases

across the alveolar-capillary junction?

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Respiratory Centre stimulants

The Respiratory Centre controls the rate and depth of breathing

• Where is the Respiratory Centre found?

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Peripheral and Central Chemoreceptors convey information to the respiratory centre to stimulate a breath

• Where are the following two types of chemoreceptors found and what causes them to alert the respiratory centre to instigate a breath?

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1. Peripheral chemoreceptors

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b. Central chemoreceptors

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Clinical focus : Action of Respiratory Centre

Explain how the following anaesthetic drugs may affect the action of the Respiratory Centre in general anaesthesia:

1. opioids

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b. anaesthetic volatile agents

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The ribs, intercostal muscles and diaphragm

Describe the structure and function of the following in enabling inspiration & expiration:

• Ribs:

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• Intercostal muscles:

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• Diaphragm:

Clinical focus point

Muscle relaxants are used routinely in the triad of general anaesthesia.

What impact may their residual post anaesthetic action have on the intercostal muscles?

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What effect would this have on respiration?

The parietal and visceral pleura

Describe the visceral, parietal pleurae and the inter pleural space.

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Explain how the action of the pleurae enable inspiration.

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Clinical focus : explain what is meant by pneumothorax.

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How may this be caused in peri-anaesthesia practice?

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Mechanics of breathing

Air moves in an out of the lungs as a result of the difference in air pressure in the

atmosphere and alveoli.

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Daltons law states : the pressure in a container is inversely proportional to its area -

‘Gases always move from an area of high to lower pressure until equal’.

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Explain how this law of physics governs the act of inspiration and expiration.

Which one of the following is true of chemical control of respiration?

1. Central chemoreceptors are found in the cerebral cortex

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• A fall in cerebrospinal fluid pH stimulates central chemoreceptors

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• Chemoreceptors are found only in the brain

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• Chemoreceptors principally detect falling 0₂ levels

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Which of the following is true [choose all that apply]

1. The respiratory centre is located in the brainstem

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• Accessory muscles of respiration include the diaphragm and the sternocleidomastoid

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• Stimulation of the aortic chemoreceptors is via the vagus nerve

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• Control of breathing is entirely involuntary

Lung Volumes

12 X 500mls = 6000mls

• To what do the numbers in the above equation refer?

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• How is this a useful equation in clinical respiratory assessment?

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• What do you understand by ‘dead space’?

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• How much air is actually involved in gas exchange? [Alveolar ventilation rate]

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• If the dead space is greater than alveolar ventilation rate what happens?

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Functional Residual Capacity

• What is this measurement?

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• Why is it important in clinical practice?

Some calculations

• If bpm = 15 & TV = 300mls. What is the MV?
• Would this be under or overventilation?

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• If MV = 7,200mls & bpm = 20. What is TV?
• Would this be under or overventilation?
• Give reasons for under/overventilation from your practice

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• Calculate the alveolar ventilation for someone whose

TV = 450mls, anatomical dead space = 160mls, & bpm = 13

Oxygen transport in blood

• What % of oxygen is dissolved in the blood?
• What % of oxygen is attached to Hb molecule?
• The oxygen dissolved in the blood exerts a partial pressure of ______
• How does this PaO₂ affect the % of oxygen which attaches to Hb?

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If the airway is obstructed and oxygen is not reaching the lungs – will the oxygen molecules:

a. remain strongly attached to Hb

b. dissociate [fall off] the Hb?

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• If oxygen dissociates from Hb molecule, what happens to the SaO₂ ?

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Carbon Dioxide transport in blood

• C0₂ is constantly produced as a waste product of_________ with water

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• The normal PaCO_{2 ______________}

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• If the PaCO₂ is elevated will the pH [acid base balance] shift to the right or left?

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• Why is this important?

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• CO₂ combines with water to form ______ to be carried in the blood to the lungs

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• Which is more soluble in blood : 0₂ or C0₂?

Gas exchange : alveoli – blood - tissues

• Gases diffuse across a membrane from an area of high pressure to low until equilibrium reached.

Explain how the

above law works

in alveolar-capillary

gas exchange.

Explain how the

above law works

in tissue-capillary

gas exchange.

List 4 essential factors needed to deliver gases to and from the atmosphere to body tissues

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Terms

What do you understand by:

• Hypoxia
• Hypoxaemia
• Anoxia
• Apnoea
• Hypoventilation
• Hyperventilation
• Hypocarbia
• Hypercarbia

2. Anaesthesia & Surgery

Why do the following groups of people pose a risk for breathing complications in the post anaesthetic period?:�

• Elderly

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• Obese

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• COPD patients

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• Smokers

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• Abdominal surgery

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Anaesthetic plan to avoid risk

• How can the anaesthetist plan to ensure that the risks [on previous slide] don’t become complications during surgery?

Anaesthetic plan

• How does the anaesthetist ensure that the patient is breathing well during surgery? [include monitoring patient, drugs, ventilation management].

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Reversal of general anaesthesia

Sometimes the patient fails to breathe well on his own at the end of surgery.

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What two drugs are sometimes administered to

stimulate breathing? How do they differ?

Despite care planning the following is a list of causes of post operative hypoxia. Fill in rationale

3. Assessment

[Physical + Risk]

How would you carry out a full physical respiratory assessment

• List check items here :

List the classic signs of hypoxia

Cyanosis

• What is the difference between peripheral and central cyanosis?

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• Cyanosis is a sign of severe hypoxia. It denotes a PaO₂ less than _________
• What happens to the SaO₂ at this critical fall in PaO₂?

What factors would you consider in carrying out a risk assessment for respiratory complications in the newly admitted patient?

Assume that you have already carried out a physical check:

Signs of respiratory impairment in patient

• List any signs that would cause you concern with the patient’s breathing

4. Breathing Management

• General

Routine respiratory care : to prevent complications

List the essential elements of routine respiratory care.

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How does routine respiratory care lessen the chance of risks becoming breathing complications?

Managing the deteriorating patient

• At what point would you call for help?

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• How would you manage the patient while waiting for help?

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• How would you ensure full flow oxygen is delivered to the patient at this time?

Identify the three stages of respiratory management

And briefly state what they entail :

5. Specific breathing complications

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• Central respiratory depression
• Residual paralysis
• Atelectasis
• Pneumothorax
• Pulmonary embolism
• Pulmonary oedema
• Asthma
• COPD

Central Respiratory Depression [hypoventilation]

• Discuss the causes of respiratory depression in the PACU
• How would you recognize this condition?
• How would you manage this condition?

Residual Paralysis [hypoventilation]

• Explain why residual paralysis may occur in the post anaesthetic period.
• Discuss the management [nursing and medical] of this condition.

Atelactasis

• What do you understand by the term ‘atelectasis’
• List risk factors for developing this condition
• How is atelectasis recognized?
• How is atelectasis managed?

Pneumothorax

• What happens to the lung in pneumothorax?
• How does this occur [in perioperative practice]?
• How is it recognised and treated?
• What happens in ‘tension pneumothorax’?
• Why is this a medical emergency?
• How is it treated?

Pulmonary Embolism

• What happens in pulmonary embolism?
• Which patients are at risk?
• What are the symptoms?
• How can the risk of embolism be prevented?
• What is the treatment for pulmonary embolism?

Pulmonary oedema

• What happens to the lungs in pulmonary odema?
• What do you understand by Negative Pressure Pulmonary Oedema? How does this occur?
• How is pulmonary oedema recognized?
• What are the main lines of treating this condition?

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Asthma

• What happens to the bronchioles in asthma?
• What drugs can exacerbate asthma?
• Why is asthma not usually a problem in peri anaesthetic care?
• How would you recognize asthma?
• What drug is used to relieve it?

Chronic Obstructive Pulmonary Disease [COPD]

• This is a broad term – what diseases does it include?
• Why does smoking lead to emphysema?
• What happens to the bronchi in chronic bronchitis?
• How is COPD managed in the post anaesthesia phase?
• Why is oxygen delivered via a venturi system in the management of this condition?

3 Clinical Scenarios

Consider the following 3 scenarios and state the possible causes of hypoventilation and management:

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Patient 87 years old: gastrectomy : 77 kgs. Surgery took 2.5 hours, patient received incremental doses of morphine 3mg x 6 + midazolam 5mgs. Patient unconscious, airway maintained with support, pale, respiratory rate 8 bpm, [shallow respirations difficult to count]. SaO₂ 93% on 6 litres of oxygen. Temperature 95 C. Pupils pinpoint.

_{Discuss this case, identify risk factors. Comment on vital signs and their significance. Outline the management needed in this situation.}

Patient 2

_{Patient 37 years old, laparoscopic sterilization : patient on fast flow day care list. Semi-conscious on 35% oxygen. Agitated, restless, facial muscular twitching, limbs jerking. Airway clear. Sa02 – 95%. Irregular breathing pattern, use of accessory muscles. BP 170/95 : HR 110. Patient known to be anxious. Atracurium : neostigmine and glycopyrrolate given intra operatively.}

_{Discuss this case, identify risk factors. Comment on vital signs and their significance. Outline the management needed in this situation.}

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Patient 3�

Patient 21 years : ORIF [R] femur following RTA : on trauma list at night. Crash induction. Right sided central line placed for fluid resuscitation. On arrival condition stable. 15 minutes after arrival, sitting up and comfortable. Sa02 98% on 35% Fi02. 3 minutes later, agitated and panics, say’s he can’t breathe. Sa02 91% : Breathing 28 bpm : Shallow resps : R side of chest wall not moving. Increasing pallor with dyspnoea, use of accessory muscles.

_{Discuss this case, identify risk factors. Comment on vital signs and their significance. Outline the management needed in this situation.}

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• We hope you have completed this workbook and have consolidated your knowledge now.
• Skill comes not only from theory and knowledge but from constant practice.
• Practice using the equipment, and your practical techniques.
• For each new patient, perform a routine airway risk assessment, compare this to the actual patient status.
• This way you will be ready for any sudden deterioration in the patient’s condition.
• This is the way to develop your critical assessment skills.

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And finally…..