Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Respiratory medicine > Respiratory failure > Flashcards

Respiratory failure Flashcards

1
Q

Type 1 Respiratory failure : Definition

A

Hypoxaemia with normocapnia
* caused by ventilation/perfusion mismatch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Type 1 Respiratory failure : Pathophysiology

A
  1. Damage to lung tissue which impairs the diffusion of oxygen across the alveolar membrane and into the blood
  2. Impaired oxygenation of the blood is the main effect - causing hypoxia
  3. Hypoxia triggers increased ventilation to improve oxygenation
  4. Increased respiratory rate - expells CO2
  5. CO2 levels is therefore - either normal or low despite hypoxemia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Type 1 Respiratory failure : ABG values

A

ABG values;
* PaO2 < 8 kPa

  • PCO2 < 6.5 kPa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Type 1 Respiratory failure : Causes

A
  1. Pulmonary oedema :
    fluid accumulation in the alveoli impairs gas exchange
  2. Pneumonia :
    inflammation and infection in the lung tissues can reduce oxygen diffusion
  3. COPD :
    narrowing of the bronchioles (Chronic bronchitis) or dilation of alveoli (Emphysema) reduces oxygen entry and surface area for oxygen diffusion.
  4. Asthma - severe bronchoconstriction during exacerbation can lead to poor oxygenation
  5. Pulmonary fibrosis : Fibrosis reduces surface area and increases the diffusion distance of the alveolar membrane leading to poor oxygen diffusion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Type 1 Respiratory failure : Pulmonary embolism and T1RF

A
  • Blood clot in the pulmonary vessels reduces the perfusion to alveolar capillaries
  • Impairing oxygen uptake and leading to hypoxia
  • Ventilation remains intact but compromise in perfusion leads to V/Q mismatch

Reduced perfusion with normal ventilation - Pulmonary embolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Type 2 Respiratory failure : Definition

A
  • Hypoxaemia with hypercapnia, caused by alveolar hypoventilation which prevents oxygenation and elimination of CO2
  • Hypercapnia is more significant.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Type 2 Respiratory failure : Pathophysiology

A
  1. Primary issue is inability to ventilate the airways by allowing air to move in and out
  2. There is hypoventilation of both expulsion of CO2 and inhalation of oxygen
  3. Inadequate gas exchange leads to - Hypoxaemia (Low O2) and Hypercapnia (High CO2)

This can be due to -
* Damage to the lung tissues limiting airflow due to narrowed bronchioles or increased resistance due to lack of lung compliance
* Mechanical impairment of intercostal and respiratory muscles for ventilation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Type 2 Respiratory failure : Causes

A

Increased airway resistance or lack of lung tissue compliance to expel
1. * COPD - narrowing of airways (Chronic bronchitis) and destruction of alveoli (emphysema) reduces ability of lungs to expel CO2 and causes impaired gas exchange
1. * Asthma - severe constriction of bronchioles prevents ventilation

Issues with mechanical ventilation
1 . Neuromuscular disorders
* Weakness of respiratory muscles prevents effective ventilation leading to impaired CO2 clearance
e.g. Myasthenia Gravis, Guillian Barre syndrome

2 . Chest wall deformities
* Restrict lung expansion thus preventing ventilation of gasses.
e.g. Scoliosis, Rib fracture, Pneumothorax

3 . Drug overdose
* Depress respiratory drive leading to muscle paralysis and inability to ventilate the lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

CO2 : Physiology in the blood

A
  1. CO2 in blood binds with water producing carbonic acid (H+ ions)which decreases PH
  2. CO2 + H2O -> H2Co3 -> HCO3- + H+
  3. Body can adjust HCO3 to counterbalance if PH abnormality is caused by respiratory system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

HCO3 : Physiology in the blood

A
  1. HCO3- produced in proximal tubule of the kidneys
  2. HCO3 is a base which helps to mop up H+ ions
  3. HCO3- + H+ -> H2CO3 -> H2O + Co2 : overall reduction in H+ ions, thus PH increases
  4. Raised HCO3 increases PH due to less H+ ions
  5. Low HCO3 decreases PH due to more H+ ions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Respiratory acidosis : Definition

A
  • Inadequate alveolar ventilation leading to CO2 retention and reduced PH
    PH : < 7.35
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Respiratory acidosis : Causes

A

Causes
* Respiratory depression
* Guillian barre : paralyse leading to inadequate ventilation
* Asthma
* COPD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Respiratory alkalosis : Definition

A

Excessive alveolar ventilation (hyperventilation) resulting in more CO2 than normal being exhaled

High PH, Low CO2 : often 2nd to response to hypoxia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Respiratory alkalosis : Causes

A
  1. Anxiety
  2. Pain : causing raised RR
  3. Hypoxia : raised RR
  4. PE : leads to T1RF secondary to V/Q mismatch due to embolism preventing perfusion of lung tissue thus leading to lack of oxygenation
    * Hypoxia then triggers increase in ventilation - increasing the respiratory rate
    * More CO2 is expelled from the lungs - leading to respiratory alkalosis

5 . Pneumothorax

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Respiratory acidosis/alkalosis : Compensatory mechanism

A
  • metabolic compensation
  • by varying the HCO3 lost in renal tubules to restore PH to normal range
  • Takes a few days for metabolic compensation to occur as it requires the kidneys to adjust HCO3 excretion/retention

Thus if immediate compensation for respiratory disorder is seen - assume respiratory derangement is chronic or ongoing for couple of days e.g. CO2 retention, leads to chronic raised bicarbs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Metabolic acidosis - definition

A

Definition : Excess acid in the bloodstream secondary to a metabolic cause
* Low PH, Low HCO3, low BE

17
Q

Metabolic acidosis - Pathophysiology

A
  1. Due to accumulation of acids in the body - thus higher concentration of H+ ions (anions) in the blood

Or

2 . Bicarbonate deficiency -
* Deficiency of HCO3- which helps to neutralise the H+ ions from the acids
* thus leading to more free H+ ions in the blood, resulting in acidity.

18
Q

Metabolic acidosis - Causes - Increased H+ in the blood

A

Increase in acid concentration of the blood

  • Lactic acidosis
    1. Lack of oxygen to tissues due to hypoxia or hypo perfusion for respiration - anaerobic respiration to metabolise glucose
    1. This produces lactic acid as a by product
    1. Lactic acid dissociates and releases H+ ions in the blood stream which lowers the pH of the blood
  • Diabetic ketoacidosis
    1. Fatty acids are broken down via lipolysis instead producing Ketone as a byproduct
    Ketones release H+ ions in the blood when they dissociate
  • **Chronic renal failure **
    1. Organic acids such as uric acid or sulphur containing amino acids accumulate and are not able to be excreted properly.
  • Addison’s disease
    1. Aldosterone deficiency leads to impaired N+/K+ regulation in the kidneys
    1. Impaired reabsorption of N+ ions into the blood in exchange for K+ secretion in the urine
    1. Excess K+ remains in the blood
    1. K+/H+ in the cell membrane of cells - moves the extra K+ into the cell and releases H+ ions in the blood stream
    1. Extra H+ ions in the blood - reduce its ph
19
Q

Metabolic acidosis - Causes - Loss of HCO3- ions

A
  1. Severe Diarrhoea
    Bicarbonate rich intestinal and pancreatic secretions are excreted via the GI tract before they can be reabsorbed
  2. **Renal tubular acidosis **
    Proximal convultured tubule is unable to reabsorb HCO3- ions leading to excess secretion
20
Q

Metabolic acidosis : Compensatory mechansism

A
  1. Respiratory compensation - (IMMEDIATE)
    * HCO3 - + H+ -> H2CO3 -> H2O + Co2
    * Chemoreceptor detect low pH and trigger increase in RR
    * Increase in RR allows for more CO2 to be expelled which is an acidic gas
  2. Renal compensation - DELAYED
    Occurs if metabolic acidosis is not 2nd to renal problem
    * Kidneys excrete more H+ ions in the urine to restore pH
    HCO3 - + H+ -> H2CO3 -> H2O + Co2
    * Reabsorb more HCO3 ions in the urine
21
Q

Metabolic acidosis : 2nd electorlyte abnormalities

A
  1. Hyperchloraemia
    * Kidneys counteract excess HCO3- loss by reabsorbing more Cl- ions
    * For every HCO3- ion lost, there is a new CL- ion reabsorbed
    * Leading to : Normal anion gap also known as Hyperchloremic metabolic acidosis
  2. Hyperkalaemia
    * H+ ions excess in the plasma can be exchanged with K+ ions in the cell
    * This lowers the H+ ions free in the blood and balances the PH
    * This can lead to excess K + ions in the blood —> Hyperkalaemia
22
Q

Metabolc acidosis : Anion gap - definition

A

Difference between the
* measured positively charged ions in the blood

Minus

  • measured negatively charged ions in the blood

Anion Gap = [Sodium (Na+)] - ([Chloride (Cl-)] + [Bicarbonate (HCO3-)])

23
Q

Metabolc acidosis : Anion gap - Which ions are measured?

A
  1. Sodium (Na+) is the major cation in the blood.
  2. Chloride (Cl-) and bicarbonate (HCO3-) are the major anions.
  3. Unmeasured cation (K+), unmeasured anions (Albumin)
24
Q

Metabolic acidosis : Normal anion gap

A

Normal anion gap range as 3 - 11 mmol/L. - referred as overall ‘Neutral’

25
Q

Metabolic acidosis : Causes of high anion gap

A

Definition
* Due to increase in positive ions - high H+ conc in the blood
* + ions > - ions

Causes
* Due to endogenous or exogenous increase in H+ ion production

DKA, Lactic acidosis, Aspirin OD, Renal failure (reduced excretion of H+ ions by kidneys)

26
Q

Metabolic acidosis : causes of normal anion gap

A

Definition
* Metabolic acidosis with normal anion gap

Causes :
* Loss of bicarbonate ions which is replaced by chloride in the plasma - thus overall stable anion concentration

GI losses - Diarrhoea, Ileostomy, prox colostomy
, Renal tubular acidosis

27
Q

Metabolic Alkalosis : Definition

A

Definition :
* metabolic alkalosis is caused by an increase in bicarbonate HCO3 ion concentration in the blood
* Elevates blood PH above 7.45
Metabolic alkalosis - decreased H+ conc, leading to increase HCO3 conc, raised PH, raised CO3, raised BE

28
Q

Metabolic Alkalosis : Causes

A

1 . Gastric losses e.g. vomiting
* Gastric fluid is made up of HCL which is has a high concentration of H+ ions
* Stomach acid is lost before they enter the intestines which is where HCO3- secretions occur
* Lack of HCO3- released by the pancreas means it builds up in the blood instead

2 . Hyperaldosteronism
* Excess aldosterone stimulates kidney tubules to increase absorption of water by retaining Na+ ions
* This also makes the distal tubules of the kidneys - excrete more + and reabsorb HCO3- ions
* Thus - excess H+

3 . Hypokalaemia
* Decreased level of potassium in the blood which can be due to excessive loss of GI tract or via the kidneys
* Low K and low blood volume triggers RAAS mechanism - aldosterone is released
* Aldosterone triggers reabsorption of HCO3- ions in the proximal convulated tubule.

4 . Renal loss of H+ ions
e.g. loop/thiazide diuretic, HF, nephrotic syndrome, cirrhosis

Respiratory medicine (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions