- Peripheral in aorta carotid body respond to Pa02 - Peripheral and central (medulla) respond to Co2

V=ventilation Q= perfusion 1. Deadspace- anatomical or disease, eg clot PE or extreme pneumothorax 2. Shunt- areas of good perfusion but POOR ventilation eg. pneumonia

Respiratory Flashcards by Emily Brayne

Inspiration is:

Active part of ventilation- diaphragm contracts via autonomic nervous system

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Respiratory rate and depth of breath is controlled by?

The Medulla Oblongata and Pons
Changes in carbon dioxide, hydrogen ion and oxygen levels in the blood
Autonomic nervous system
Chemo and stretch receptors

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Oxygen dissociation is potentiated by:

Pyrexia
Acidosis
Hypercarbia
Hypercapnia

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Adequate oxygenation requires:

Ventilation
Diffusion
Perfusion

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Purpose of surfactant in alveoli

Reduces surface tension of water
Increases pulmonary compliance
Prevents atelectasis at end of expiration

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Oxygen debt causes cells to do what?

Metabolise glucose into lactic acid

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Aerobic Metabolism turns oxygen and glucose into:

Heat (Kcal)
Carbon Dioxide (Co2)
Water (H20)
Adenosine triphosphate (ATP)

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Serous membrane lining the lungs

Visceral pleura

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Ventilation is

Movement of gases between the atmosphere and alveoli

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Respiration occurs at three levels :

Ventilation
External Respiration
Internal Respiration

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Functions of the Larynx

Contains epiglottis which protects trachea from aspiration
Contain the vocal cords
Forms part of the anatomical deadspace
Contains cricoid and thyroid

It does NOT filter out particles

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Expiration is:

Passive
Involves the relaxation of diaphragm
Involves the recoil of the lungs

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Causes of respiratory failure

Atelectasis
Pneumonia/infection
COPD (asthma/chronic bronchitis/emphysema)
Pulmonary embolism
Haemothorax/pneumothorax
Secondary to cardiac failure
Drugs
Neurological

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Symptoms of Respiratory Failure

Increases work of breathing=hypoxia=cyansis=silent chest
Hyperdynamics=shock=poor perfusion=circulatory collapse
Altered mental state=exhaustion=coma

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Chemoreceptors:

Peripheral in aorta carotid body respond to Pa02

- Peripheral and central (medulla) respond to Co2

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Stretch Receptors

In trachea and bronchial smooth muscle- detect over stretch and stimulate expiration (relaxation of diaphragm is active in this case) to reduce chance of overinflation/barotrauma to lungs

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VQ ratio Mismatch

V=ventilation
Q= perfusion

Deadspace- anatomical or disease, eg clot PE or extreme pneumothorax
Shunt- areas of good perfusion but POOR ventilation eg. pneumonia

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Deadspace is:

Areas within respiratory system that are ventilated but not perfused.
Ie. Trachea, bronchi and bronchioles

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Respiration is:

Ventilation- active and passive

External Respiration- gas exchange within lungs

Internal Respiration- within tissues at cell level

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Lines thoracic wall

Parietal Pleura

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Fluid filled space surrounding lungs

Pleural Cavity

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Daltons Law

Gases exert pressure against each other- this partial pressure = p

p02+pco2+pN2+pH20=. 101kPa

oxygen 21%
Nitrogen 79%

Gasses diffuse from areas of high to low pressure

Henry’s Law

The amount of gas that will dissolve in liquid is proportional to the partial pressure of the gas and its solubility coefficient- when temperature is constant.

Arterial Blood Gas Interpretation

pH- H+ ions

pCO2- partial pressure of arterial CO2

pO2- the partial pressure of arterial O2

HCO3 sodium bicarb- bicard in plasma

Base Excess- the amount of bicarb needed to return an equilibrium

Control of pH- RESP

Normal pH 7.4 H2O + CO2 ----> H2CO3 (carbonic acid) Resp= increases RR to blow off acidic CO2

Control of pH- RENAL

In acidosis kidneys eliminate H+ and retain HCO3 In alkalosis kidneys eliminate HCO3 and retain H+ via urine

Control of pH- Buffering systems

Bicarbonate Haemolglobin/proteins Inorganic phosphates and other buffers

Buffering

Co2+H2o H2Co3H+ + HC03 Intermediate + natural =compensation VS Treatment + medically managed =correction

Partial or Complete compensation

Partial= pH normal but other systems involved Complete= pH normal and other systems corrected

Type 1 Respiratory Failure

PaO2 <8 with normal or low CO2 Acute hypoxic event- asthma, pneumonia, ARDS

Type 2 Respiratory Failure

PaO2<8 and CO2 >6.1 (ventilation failure) chronic, chest wall deformities, Respiratory depression

Chemoreceptors and CO2

Co2 diffuses into CSF ---> Carbonic Acid H2CO3

Analysing Gases

HCO3 if low + pH low = metabolic acidosis HCO3 in high and pH high= metabolic alkalosis BE- metabolic PaCO2 and PaCO2- respiratory or pH

Breath Sounds

Vesicular Breath- normal Bronchial Breath- higher pitch Added breath sounds- crackles (fine/coarse) or wheeze (mono/polyphonic)

Functional Residual Capacity

Volume left post expiration

PEEP

- Positive end expiratory pressure - Increases gas exchange (external respiration - increases functional residual capacity - Maintains open airways

PRESSURE SUPPORT

-Increases tidal volume -Increases Co2 removal -Supports inspiration start at 5 to 8 above peep

Tidal Volume normal values

6-8ml/kg

Rapid sequence induction

Sedation- Propofol/Medaz Opiate- Fentanyl Paralysis- Rocuronium BP- Metaraminol

Pressure Modes Ventilation

CPAP/PS SIMV PS/PC Automode PRVC

Volume Modes Ventilation

SIMV VS/VC Automode VS/VC PRVC

Ventilator induced lung injury

Barotrauma (high pressure) Volutrauma (high volumes) BOTH CAUSE Pneumothorax Atelectatrauma (shear stress on alveoli) Biotrauma (inflammation)- Similar to ARDS

OXYGEN TOXICITY

Caused by free radicals

Effects on CVS with Positive Pressure Ventilation

Increases intra-thoracic pressure =reduces venous return Increases pulmonary resistance =decreases cardiac output

Effects on Renal with Positive Pressure Ventilation

Reduced Cardiac output =reduced renal perfusion Increase in sympathetic activity= increased ADH production, Aldosterone and increased H20 and Na reabsorption AND Increase in thoracic pressure= reduced ANP production = increased Na reabsorption

Effects on Liver with Positive Pressure Ventilation

Reduced cardiac output= reduced hepatic flow Increased intra-thoracic pressure = increased hepatic congestion

Effects on CNS with Positive Pressure Ventilation

Increased intra-thoracic pressure= Increased ICP and ICC Reduced cardiac output= reduced blood flow to brain

Nurses role in reduction of VAP

- Subglottic aspirates - Oral hygiene - Tracheal cuff pressure +regulation - Positioning 30 degree - PPI/stress ulcer prophylaxis - Sedation level assessment

Tracheostomy Indications

- Upper airway obstruction - Surgical procedure - Respiratory insufficiency - Neuromuscular Disorders- MND - Long term ventilation

Vital Capacity

Volume of air you can expel on expiration with max effort

Inspiratory Capacity

Maximum volume that can be inspired

Tidal volume

Amount of air that moves in or out per Respiratory cycle

SPUTUM

- Produced by goblet cells - Normally cleared by cilia and cough Cleared using direct percussion/ViBS- not good for trauma patients, bleeds pneumothorax and hernias Postural drainage- not good for ICP, post meds or cardio instability

NORMAL ABG VALUES

``` pH 7.35-7.45 PaO2 12-14kPa PaCo2 4.6-5.9 kPA HCO3 22-26mmols/L Base Excess +2/-2 ```