Positioning to maximise lung function

Question 1

what do lungs require for respiratory function

Answer 1

lungs require- adequate ventilation of alveoli, adequate blood supply to exchange and transport 02, C02

Question 2

ventilation perfusion matching

Answer 2

for gas exchange to occur ventilation and perfusion need to be in the same place at the same time- blood and air. this is V/Q matching (V/Q ratio), perfect match 1/1, we require 0.8/1)

Question 3

how do V/Q change

Answer 3

they increase independently from top to bottom of the lung, this change occurs in the vertical plane regardless of body position Q is increased to a greater extent because gravity exerts a greater effect on blood than inspired air

Question 4

why is the dependent (lower) region of the lungs are better ventilated

Answer 4

alveoli in the non-depdent region (upper) are already inflated because of the weight of the lung hanging in thorax- already at max- cant open more
in addition, in side-lying the lower hemi-diaphragm is pre stretched by abdominal pressure and therefore has a mechanical advantage over the upper hemi-diaphragm causing twice the excursion

Question 5

what is ventilation

Answer 5

this is the movement of air in and out of the lung. not evenly distributed. primarily gravity dependent in the spontaneously breathing adult. follows a ventilation gradient, down the lung

Question 6

what is perfusion

Answer 6

blood flow in the capillary bed. gravity dependent in the spontaneously breathing adult. follows a perfusion gradient down the lung tissue. changes with exercise (increase blood flow) and posture (effects where blood is)

Question 7

regional difference in ventilation

Answer 7

lower regions ventilate better than upper. intrapleural pressure is less negative at the bottom than the top of the lungs- as pleura are being pulled out. lower lungs have greater potential for increase ventilation. alveoli in lower region have greater ability to expand

Question 8

factors affecting V/Q- ventilation

Answer 8

pleural pressure, altered lung compliance/ expandability, altered airway resistance, airflow resistance, lung volume, physiologic dead space, shunt

Question 9

factors affecting V/Q- perfusion

Answer 9

wastes ventilation, circulatory disorders

Question 10

abnormal VQ

Answer 10

wastes perfusion or shunt where there is adequate blood supply but there is problem getting gas to it (consolidation) or caused by wasted ventilation- gases available but problem with blood supply- blockage

Question 11

use of body position to:

Answer 11

maximise ventilation, maximise diaphragmatic function, optimise V/Q matching, but also decrease WOB and drain sputum

Question 12

why does mechanical ventilation reverse ventilation away from the dependent lung

Answer 12

the diaphragm is pushed down passively. airflow takes the path of least resistance. increased perfusion in depend regions compresses lung and accentuates the perfusion gradient. absorption atelectasis at higher oxygen concentrations, cannot get V/Q max

Question 13

why are dependent regions more prone to collapse- mechanical ventilation

Answer 13

due to lack of nitrogen

Question 14

if patient on mechanical ventilation and sidelying

Answer 14

perfusion not affected- occurs most in lung that is lower most, ventilation- occurs mainly in upper lung as it hangs in chest wall and is already open,

Question 15

lung volume- total lung capacity (TLC)

Answer 15

total volume of gas in lungs after maximum inspiration- between 3 and 8 litres- dependent on persons size and sex, sum of- respiratory volume, inspiratory reserve volume, expiratory reserve volume, tidal volume

Question 16

lung volume- vital capacity

Answer 16

volume of gas exhaled after full inspiration- 3-6 litres- used in pulmonary function test- force VC

Question 17

lung volume- residual volume

Answer 17

volume of air in lungs after expiration- 1 litre

Question 18

lung volume- expiratory residual capacity

Answer 18

extra volume of gas that can be exhaled forcefully when you reach end of TV- 1 litre

Question 19

lung volume- functional residual capacity

Answer 19

volume of gas remaining at end of TV expiration, reflects good resting position, inward and outward elastic recoil are balanced, reduced in restrictive diseases, increased in hyperinflated disease- 2 liters, lowers closes we get to supine

Question 20

lung volume- inspiratory reserve volume

Answer 20

extra volume of gas inhaled voluntarily at the end of inspiration TC- used in deep breathing exercises/ exercise- 3 litres

Question 21

lung volume- tidal volume and closing volume

Answer 21

volume of gas exhaled and inhaled during one respiratory cycle- resting volume 300-800ml
closing volume- volume at which alveoli start to collapse

Question 22

what causes variations in lung volume

Answer 22

body size, age, sex, muscular training, lung pathology

Question 23

FRC and closing volume

Answer 23

have a close relationship, if FRC decreases you are more likely to get close to closing volume. patients with low FRC- have areas where alveoli are collapsed down

Question 24

what is dead space

Answer 24

volume of air inhaled but not used in gas exchange

Question 25

dead space- anatomical dead space

Answer 25

gas left within mouth and trachea when we breath- not involved with gas exchange

Question 26

dead space- alveolar dead space and physiological dead space

Answer 26

alveolar- air in alveoli that should be involved with gas exchange, but due to low blood supply it isn’t
physiological- sum of both anatomical and alveolar dead space

Question 27

dead space- treatment

Answer 27

with any treatment/ intervention we want to avoid increasing dead space
ventilators- increases anatomical dead space

Question 28

breathing re-education-

Answer 28

in patients with chronic diseases the aims are normally to reduce WOB and give patients confidence in their ability to control breathless attacks. minimalist approach is advised, their unnatural breathing pattern may be optimum for them if breathing is irregular, paradoxical or unnecessarily tense, this is useful to improve breathing efficiency

Question 29

breathing re-education- breathing technique

Answer 29

practice can enable a breathing technique to be used more easily when required, especially when getting their breath back after exertion

Question 30

breathing re-education- acute problems

Answer 30

in patients with acute problem it is often to help reverse the problem or treat the signs and symptoms manifesting themselves as a consequence

Question 31

what is diaphragmatic breathing

Answer 31

breathing using abdominal movement reducing the degree of chest wall movement as much as possible
interchangeable with breathing control

Question 32

what is breathing control

Answer 32

normal tidal breathing encouraging relaxation of the upper chest and shoulders, interchangable with diaphragmatic breathing

Question 33

abdominal/ diaphragmatic breathing thought to

Answer 33

decrease airway turbulence, decrease dead space, favour dependent regions, relaxes shoulder girdle

Question 34

abdominal/ diaphragmatic breathing instructions

Answer 34

relaxed position, rest a hand on abdomen, keep shoulders relaxed, breath in slowly so hand rises, sigh out, tru and increase depth of breathing

Question 35

deep breathing- what does it do

Answer 35

increase lung volume, increase ventilation, decrease airway resistance, increase surfactant secretions, aid V/Q matching, decrease dead space, increase diffusion, increase O2 saturation

Question 36

deep breathing instructions

Answer 36

breath in deeply via nose, breath out of mouth- relaxed not forced, physiotherapist place hands on thorax (both sides), 3-4 breaths then rest, use breath hold at full inspiration (count of 3), possible sniff

Question 37

what is therapeutic positioning

Answer 37

the placement of the patient or a body part to promote physiological and/or psychological well being. used to address more than one system. Position patients to optimise arterial oxygenation by placing most compromised area uppermost- avoid slumped position,

Question 38

therapeutic positioning- problem

Answer 38

reduced arterial oxygen or saturations, SOB, SOBAR, SOBOE, increased work of breathing, reduced lung volume, excess sputum

Question 39

what effects closing volume

Answer 39

increases with age, smoking, lung disease, and body postion

Question 40

closing volume- other implications

Answer 40

FRC decreases with obesity, supine position, anaesthetic/ post- surgery which increases the risk

Question 41

breathlessness/ WOB

Answer 41

High WOB results in breathlessness and distressed breathing pattern. increases energy use and therefore oxygen demand. position to optimise respiratory function without excess energy demand. optimise diaphragm, decrease active fixation of shoulder girdle which uses muscular contractions

Question 42

therapeutic positions

Answer 42

sitting in chair with elbows on knee- fixing, leaning with back against wall, sitting on chair with cushions on table- sleeping position, standing and fixing on table/side, sleeping position- pillow across chest- opens up airways