Respiratory Trauma Flashcards
What are the 4 classifications of hypoxia?
Hypoxic hypoxia (low O2 supply) Anaemic hypoxia (low Hb function) Stagnant hypoxia (inadequate circulation) Histotoxic hypoxia (impaired cellular O2 metabolism)
What happens to CO2 &O2 in type 1&2 respiratory failure? How is it diagnosed?
1: HYPOXIA pCO2= normal, ↓pO2 <8 on air 2: HYPOXIA W/HYERCAPNIA pCO2↑ , ↓pO2 <8 on air Diagnosed: ABG, CXR
What is the pathophysiology & cause of type 1 respiratory failure?
V/Q mismatch
Alveolus perfused (receiving venous blood from RV) but not oxygenated (alveolus malfunctioning- filled w/fluid in pneumonia/HF)
Blood remains deoxygenated & mixes w/oxygenated blood from other alveoli.
Multiple alveoli affected proportion of blood entering LA deoxygenated enough to dilute blood= hypoxic
CAUSE: V/Q mismatch, Upper airway obstruction, low O2 in inspired air
Low= Obstruction, mucus plug in asthma/COPD, airway collapse in emphysema
High= Block in blood flow, PE
What is the cause of type 2 respiratory failure?
Damage to lungs= inc alveolar resistance (structural/ inc secretions). Amount of air entering alveoli is limited w/added ineffective gas exchange. Air enters alveoli but nothing happens
CAUSES:
Hypoventilation- Drug OD, weakness
Increased dead space: COPD, restrictive lung disease, dec resp drive, NM disease, thoracic wall disease
What is the calculation for the delivery of oxygen?
DO2= 10 x CO x Conc of O2 in the blood
Define obstructive lung disease
How can it occur?
Narrowing of pulmonary airways hinder a person’s ability to completely expel air from the lungs
Affect the bronchi and bronchioles, usually in a diffuse pattern across the whole lung
E.g: COPD, Asthma, Bronchiectasis, CF
Define restrictive lung disease
How can it occur?
Cannot fully fill their lungs with air.
Stiffness & reduced compliance in the lungs, chest wall, weak muscles, or damaged nerves may cause the restriction in lung expansion
Increase in the amount of tissue in the interstitium of the lung
E.g: Interstitial lung disease (pulmonary fibrosis), Sarcoidosis, Obesity, Muscular atrophy & ALS
What is the pattern seen in obstructive lung disease?
Reduced peak flow
Reduced FEV1:FVC ratio <70%
Reduced FVC <80% of normal
What is the pattern seen in restrictive lung disease?
Reduced FVC
Reduced FEV1
Normal PEFR
Normal FEV1: FVC ratio
What are the complications of invasive ventilation?
Complications: Upper airway trauma, local irritation, laryngospasm, aspiration
What are the complications of non-invasive ventilation?
Complications: CPAP/BiPAP- gastric distension, dec CO, mucus plug, pneumothorax, hypT
Bag&mask- Aspiration, hypoventilation
How is MAP calculated?
MAP= 2x D.BP + S.BP/3
Define flail chest
> 2ribs fractured in >2 places
What size ET tube is usually used for men & women?
M: 8
W: 7
What are the 4 checks used to make sure an ET tube is in the correct position?
Chest rise & fall
Tube has gone past the cords
CO2/ misting of the mask / O2 sats holding
Audible/auscultate breath sounds
Who is CPAP used for?
High pressure air/oxygen with a tight fitting mask.
Positive pressure between 4-25cm H2O during inspiration AND expiration
Improves: FRC, V/Q match
Decreases: Atelectasis, leakage of fluid into lung
USE: Acute hypoxic respiratory failure (TYPE 1) Acute pulmonary oedema Fluid overload (HF) Atelectasis Chest infection Sleep apnoea Assist weaning from invasive ventilation
Who is BiPAP used for?
high positive pressure on inspiration and lower positive pressure on expiration.
Increases minute vol by increasing tidal vol
Type 2 respiratory failure
Hypercapnoeic COPD exacerbations
MSK conditions w/resp failure
Obesity hyperventilation syndrome
In a trauma patient, when is intubation a definite?
GCS <8
What are the contraindications for CPAP/BiPAP?
MUST BE ABLE TO: Maintain own airway, cough, make own respiratory effort Undrained pneumothorax Severe epistaxis Vomiting Apnoea Severe agitation Unable to tolerate or fit mask Low GCS Asthma or pneumonia (unless not for intubation)
What investigations should be done for breathlessness?
Bloods ABG CXR ECG CTPA or V/Q scan
What is IPPV?
Intermittent
Positive
Pressure
Ventilation
Ventilator creates positive pressure in ET tube driving air into lungs
Can be set to specifics: breaths/min, O2 conc, tidal vol
Optimises patients oxygenation & ventilation
What are the problems with CPAP?
hypoT
Expand pneumothoraces
Difficult to apply if facial injuries
What is the mechanism of hypercapnoea in COPD?
Combination of muscle fatigue & worsening lung mechanisms
Inc bronchial constriction, narrowing, oedema
Disordered central ventilatory drive
What are the problems with IPPV?
Requires ET tube Sedation HypoT Gastroparesis Immobility Vascular access Inc risk of pneumonia ICU requirement
