Respiratory failure clinical signs and symptoms quiz Flashcards
Somnolence
is a state of strong desire for sleep, or sleeping for unusually long periods (compare hypersomnia).
A 35 year old woman develops Guillain–Barré syndrome after infection with Campylobacter jejuni from eating undercooked turkey. Her initial symptoms include a sensation of pins and needles and pain over her back, along with mild muscle weakness in the feet and hands. However, within a few hours she notes the weakness spreading to her arms and upper body and complains of difficulty breathing; her wife calls 999. By the time the ambulance arrives the patient is somnolent. An initial arterial blood gas in this patient would show which of the following?
a) Type One Respiratory failure with low PaO2 (<8 kPa) and low PaCO2 (<4.6 kPa)
b) Type One Respiratory Failure with low PaO2 (<8 kPa) and normal PaCO2 (4.6-6 kPa)
c) Type One Respiratory Failure with low PaO2 (<8 kPa) and high PaCO2 (>6 kPa)
d) Type Two Respiratory Failure with low PaO2 (<8 kPa) and normal PaCO2 (4.6-6 kPa)
e) Type Two Respiratory Failure with low PaO2 (<8 kPa) and high PaCO2 (>6 kPa).
e) Type Two Respiratory Failure with low PaO2 (<8 kPa) and high PaCO2 (>6 kPa).
• Any muscle weakness syndrome that leads to diffuse, all lung hypoventilation will
cause Type Two Respiratory Failure (RF) – low PaO2 and high PaCO2
• By definition, Type One RF is characterised as low PaO2 with low or normal PaCO2
To answer this question correctly you have to remember the definitions of Type 1 vs Type 2 RF, and you have to remember that diffuse muscle weakness causes hypoventilation of all the lung and this leads to Type 2 RF.
Remember other causes of hypoventilation throughout the lungs include opioid overdose, brainstem injury, muscular dystrophy, severe kyphoscoliosis – always leads to Type 2 RF
A 35 y/o man presents to his GP with 48 hours history of cough productive purulent sputum, fevers, chills and myalgias. The GP hears crackles on the lung exam suggestive of pneumonia and sends the patient for a chest x-ray that reveals a right middle lobe pneumonia. Where on the lung exam of this patient was the GP most likely to have heard the crackles?
a) A
b) B
c) C
d) D
e) E
f) F
g) G
h) H
i) I
C
Remember the right middle lobe is almost entirely anterior and lateral
• One of the causes of Type One Respiratory Failure is low inspired pO2 as can occur at high elevations such as those encountered during mountain climbing. Proper training decreases the risk of respiratory failure, but even in well trained individuals, past a certain elevation, supplemental oxygen is required. Sherpas, a Tibetan ethnic group who live in the mountainous regions of Nepal, only require oxygen at the highest peaks; most foreign climbers turn on their oxygen tanks at about 7,100m whereas Sherpas usually don their mask at about 7,950m. Adaptations that Sherpas have undergone enabling this tolerance for low inspired PO2 include which of the following?
a) Increasedhaemoglobinoxygenaffinitysecondarytoincreased2,3DPGreflectedintheoxygen- haemoglobin curve being shifted to the right
b) Decreasedhaemoglobinoxygenaffinitysecondarytoincreased2,3DPGreflectedintheoxygen- haemoglobin curve being shifted to the left
c) Increasedhaemoglobinoxygenaffinitysecondarytodecreased2,3DPGreflectedintheoxygen- haemoglobin curve being shifted to the right
d) Decreasedhaemoglobinoxygenaffinitysecondarytoincreased2,3DPGreflectedintheoxygen- haemoglobin curve being shifted to the right
e) Decreasedhaemoglobinoxygenaffinitysecondarytodecreased2,3DPGreflectedintheoxygen- haemoglobin curve being shifted to the right
The correct answer is D - Decreased haemoglobin oxygen affinity secondary to increased 2,3 DPG reflected in the oxygen- haemoglobin curve being shifted to the right
Remember, anything that shifts the oxygen haemoglobin dissociation curve to the RIGHT represents decreased affinity of oxygen for haemoglobin and hence easier release of oxygen hence increasing oxygen delivery.
Remember INCREASED 2,3 DPG shifts the curve to the right, thus increasing oxygen release and delivery – and 2,3 DPG levels increase at high altitude and other causes of hypoxia including anaemia – thus increasing oxygen availability to tissues.
Higher temperature and lower pH (i.e. higher proton concentrations) also shift the curve to the right
A 35 y/o man presents to his GP with 48 hours history of cough productive purulent sputum, fevers, chills and myalgias. The GP hears crackles on the lung exam suggestive of pneumonia and sends the patient for a chest x-ray that reveals a right lower lobe pneumonia. Where on the lung exam of this patient was the GP most likely to have heard the crackles?
a) A
b) B
c) C
d) D
e) E
f) F
g) G
h) H
i) I
The correct answer is I
Remember the right lower lobe is almost entirely posterior and lateral
A 22 y/o man presents in type 1 respiratory failure secondary to an acute, severe asthma attack. Which of the following lung volume(s) would be increased in this patient secondary to the increased air trapping that occurs in asthma exacerbations?
a) Residual Volume; labelled as A
b) Residual Volume; labelled as B
c) Vital Capacity; labelled as C
d) Vital Capacity; labelled as D
e) Functional Residual Capacity labelled as E
The correct answer is a - Residual volume labelled as A.
Answer b is incorrect because although it uses the correct name for the volume that is increased in an acute asthma attack - residual volume – on the diagramme what has been labelled as B is actually the functional residual capacity (FRC).
Answer c is incorrect because, although it is correctly labelled - i.e. C IS the vital capacity, the vital capacity in asthma is typically normal or reduced - this is because there is less air moving in and out of the lungs
Answer d is incorrect because it is incorrectly labelled - i.e. D IS NOT the vital capacity (and as above)
Answer e is incorrect because the volume that is labelled is not the FRC but rather the inspiratory reserve volume - NB - FRC will also be increased in asthma because of the increase in residual volume secondary to air trapping
Mr.. Roberts, a 74 y/o man with a history of hypertension and T2DM, is admitted with a CVA causing dysphasia and right sided paralysis. Mr. Roberts is assessed as high risk for aspiration pneumonia because he has lost his cough reflex, a relatively common occurrence status post significant CVA that occurs because of impaired motor responses. If we analysed Mr. Roberts motor responses in the context of his cough reflex which muscles would we predict would have impaired function?
a) Internal intercostal muscles and diaphragm
b) Internal intercostal muscles and abdominal muscles
c) Externalintercostalmusclesanddiaphragm
d) External intercostal muscles and abdominal muscles
e) InternalandExternalintercostalmuscles
The correct answer is b- internal intercostal muscles and abdominal muscles
In order to answer this question, you have to remember that cough depends on an “explosive expulsion” of air - and this requires the expiratory muscles.
Now, normally, during “quiet expiration”, expiration is a passive process that results because of the relaxation of the inspiratory muscles. BUT in forced expiration - such as occurs in a cough- we are using the accessory muscles of expiration which are the internal intercostal muscles and the abdominal muscles.
a is wrong because the diaphragm is the muscle of inspiration
c is wrong because the external intercostal muscles and diaphragm are the muscles of normal inspiration - and, yes, we need to breathe in in order to have air to cough out, but these muscles are still working as we are not told that the patient required intubation
d is wrong because the external intercostal muscles are muscles of inspiration
e is wrong because - again- external intercostal muscles are included in the answer
A 60-year-old man has smoked 30 cigarettes/day since the age of 18. He has had a troublesome cough for a few weeks and has recently developed hoarseness of voice. Fiberoptic laryngoscopy shows a left vocal cord paralysis. Further investigations reveal a bronchial carcinoma.
7a: Calculate his smoking history in pack years
7b: Referring to the relevant anatomy, briefly explain how a bronchial carcinoma could cause a left vocal cord paralysis and hoarseness?
1 pack year = 20 cigs a day
30/20= 1.5
1.5 x 42 years= 63
The left recurrent laryngeal nerve descends into the thorax, winds around the arch of the aorta and travels back up to the larynx
The nerve can be damaged in the thorax by the bronchial carcinoma (and/ or mediastinal lymph node enlargement), thus causing left vocal cord paralysis
7c: Briefly outline the normal cough reflex
- Deep inspiration followed by closure of glottis
- Strong contraction of the expiratory muscles, while glottis remains closed
- Sudden opening of the glottis causes an explosive discharge of air.
7d: Briefly explain why the cough may become less effective following the left vocal cord paralysis
- In vocal cord paralysis, the glottis cannot be closed properly,
- so, muscle contraction cannot build up intrapulmonary pressure 3. Therefore the cough is less effective
• A 35 year old man is brought into the emergency department with sudden onset breathlessness and pleuritic chest pain. A chest x-ray shows a pneumothorax.
8a: His chest x-ray is shown. Using labelled arrows identify and state 2 features of a pneumothorax seen in this x-ray.
- collapsed lung- lack of peripheral lung markding s
- deviation of the trachea towards pneumothorax side
Ms. Lake, a 30 y/o woman who no significant past medical history other than a BMI of 32, is admitted to hospital after falling off her bicycle and sustaining a compound fracture of the left humorous requiring open reduction and internal fixation. She has smoked 1 pack per day since age 15. Her only medications are oral contraceptives. Ms. Lake is in hospital for three days and set to be discharged on day four when she has an unwitnessed syncopal episode after getting up to use the bathroom. By the time her physician arrives her blood pressure is 120/80, RR is 34 breathes/minute and heart rate 105 bpm; on further discussion Ms. Lake states that she feels short of breath. Bedside pulse oximeter shows 88% saturation. ECG shows sinus tachycardia. The physician, suspecting pulmonary embolism, orders a stat Arterial Blood Gas and CT pulmonary angiogram (CTPA)that confirms the diagnosis of PE. Ms. Lake is placed on oxygen 4 L nasal cannula. What type of respiratory failure would Ms. Lake’s initial arterial blood gas most likely show, and what would the follow up ABG on supplemental oxygen most likely show?
a) Initial would show Type One Respiratory failure with low PaO2 and low PaCO2; follow up improved PaO2.
b) Initial would show Type One Respiratory Failure with low PaO2 and normal PaCO2; follow up improved PaO2
c) Initial would show Type One Respiratory failure with low PaO2 and low PaCO2; follow up would not be changed significantly.
d) Initial would show Type Two Respiratory Failure with low PaO2 and elevated PaCO2; follow up improved PaO2 and unchanged PaCO2.
e) Initial would show Type Two Respiratory Failure with low PaO2 and high PaCO2; follow up improved PaO2 with elevated PaCO2.
• The correct answer is a - Initial would show Type One Respiratory failure with low PaO2 and low PaCO2;
b is incorrect because she is hyperventilating, and we would predict her CO2 would thus be below normal
c is incorrect because the hypoxaemia secondary to a moderate PE is caused by V/Q mismatch- and thus would improve with oxygen therapy (a massive PE with right sided heart failure may only minimally improve with oxygen therapy (or not improve at all) but the patients blood pressure does not suggest haemodynamic instability.
d is incorrect because PE does not typically cause T2RF
e is incorrect one because PE does not typically cause T2RF and two because we are not given any history to suggest this patient would be at risk for oxygen induced hypercapnia
