Surgery

Question 1

Who is most at risk going under anaesthetic?

Answer 1

Smokers, obese, elderly, malnourished

Question 2

Smokers

Answer 2

Decreased cilial activity
Increased bronchial secretions
Weak immune system
Higher closing volume

Question 3

Elderly

Answer 3

Decreased lung compliance
Stiffer thoracic cage
Reduced effectiveness of thermoregulation- anaesthetic affects re-distribution of body heat, can change core temp by 0.5-1.5 which can be dangerous for elderly. Elderly more likely to drop temp and not recover quickly.

Question 4

Obese

Answer 4

Reduced FRC
Higher CC
Increased effort to move thoracic cage
Poor basal expansion

Question 5

Effect of upper abdominal surgery

Answer 5

Affects diaphragm function

Patient’s won’t want to take deep breaths so at risk for atelectasis

Question 6

Surgery complications

Answer 6

Pain
Reduced lung volumes- FRC, VC
Retained secretions
Increased work of breathing
Decreased exercise tolerance
Hypoxaemia
Respiratory muscle weakness

Question 7

Why are the lower lobes most at risk of atelectasis?

Answer 7

Because they are the last to receive oxygen especially when in pain

Question 8

Thrombosis

Answer 8

Caused by immobility
Fluid loss
Abnormal clotting
Calf compression

Question 9

When is generally the greatest reduction in FRC post op?

Answer 9

1st/2nd day

Question 10

Obesity and FRC

Answer 10

Massive reduction in FRC post op

Question 11

Effect of general anaesthetic on respiratory system

Answer 11

Reduced lung volumes

Especially FRC

Question 12

VC and FRC after surgery

Answer 12

VC can reduce to 40% of pre op values

FRC can reduce to 70% of pre op values

Question 13

How long do VC and FRC changes last?

Answer 13

5-10 days

Question 14

Relationship between FRC and closing capacity (CC)

Answer 14

FRC normally exceeds CC, so small airways stay open at end of quiet expiration.
But if FRC falls below CC or CC rises above FRC, this could result in V/Q mismatch and hypoxaemia.

Question 15

What are 2 inevitable consequences of major surgery?

Answer 15

Post op hypoxaemia and atelectasis

Question 16

How can we counter these consequences?

Answer 16

Early upright positioning and mobilization

Because this will optimize FRC

Question 17

Post op pulmonary complications can cause…

Answer 17

Post op morbidity and mortality.

Increased length of stay.

Question 18

PPC risk factors

Answer 18

Anaesthesia duration greater than 180 minutes
Type of surgery- upper abdominal
Current smoking (within last 8 weeks)
Presence of pre op respiratory problems
Reduced level of pre op activity
Sleep apnoea
Advanced age

Question 19

What can exacerbate post op changes such as impaired respiratory fucntion?

Answer 19

Obesity

Question 20

Positioning after pneumonectomy

Answer 20

Positioned onto operated side so remaining lung is uppermost

Question 21

What is a serious complication of pneumonectomy?

Answer 21

Pulmonary oedema

Look for a positive fluid balance, with tachycardia, tachypnoea and hypoxaemia

Question 22

Positioning after oesophageal surgery

Answer 22

Avoid head down positioning
To prevent gastric reflux which can lead to aspiration
Avoid neck extension

Question 23

Positioning after lobectomy and pleurectomy

Answer 23

Side lying and head down has no contraindication

Question 24

Thoracic surgery and positive pressure therapies

Answer 24

With caution or not at all

Question 25

Management of sternal and rib fractures

Answer 25

Requires effective pain relief to prevent hypoventilation | Ensure they can take a deep breath

Question 26

Flail chest

Answer 26

Where 2 or more ribs are fractured in 2 or more places leading to a floating segment Causes severe pain and increased WOB which can lead to respiratory failure due to poor ventilation of underlying lung.

Question 27

Treatment for flail segment

Answer 27

CPAP

Question 28

Effect of prolonged recumbency

Answer 28

Reduces ventilation to lung bases, causes poling of intra-thoracic blood to these regions which upsets V/Q.

Question 29

Cause of brief post op hypoxaemia

Answer 29

Due to anaesthetic | Requires brief oxygen therapy

Question 30

Cause of post op hypoxaemia for several days

Answer 30

Related to the surgery | Major surgery requires post op oxygen therapy for at least 72 hours

Question 31

What is common after CV surgery?

Answer 31

Atrial fibrillation | Usually second day

Question 32

Melbourne group scale

Answer 32

PPC diagnosed with four of more of: CXR shows atelectasis/consolidation Fever with raised temp WCC of more than 11.2 SpO2 less than 90% on room air Production of yellow/green sputum differing from preop status Signs of infection on microbiology Diagnosis of pneumonia or chest infection by attending physician Readmission to ICU with respiratory problems or >36 hours stay in ICU or abnormal breath sounds differing to pre op status

Question 33

Incidence of atelectasis

Answer 33

0-5% in lower abdominal surgery 19-59% in thoracic surgery 88% in upper abdominal surgery.