Flashcards in Chest wall - OCT?? Deck (134):
The diaphragm is innervated by what?
Which nerves supply the intercostal muscles?
Both the external and internal muscles are innervated by the intercostal nerves (the ventral rami of thoracic spinal nerves).
Which part of the brain stem initiates breathing?
A "cut" above c3 will cause which important muscle to cease work? What impact will this have?
Diaphragm. You'll cease breathing!
The Lumsden transections are strong evidence for what?
The origin of spirometry rhythm in the medulla oblongata
What are the names given to the respiratory neurones in the medulla?
There are two symetrical groups on either side:
DRG: Dorsal respiratory group
VRG: Ventral respiratory group
DRG neurones fire during ____.
VRG neurones fire mainly during ___.
Distributed network models refers to which hypothesis?
The respiratory rhythm begins in networks of respiratory neurones - not in any particular place - arising from distributed networks of neurones.
Single oscillator models refer to which hypothesis?
The hypothesis that there ARE distinct groups of neurones, that do generate rhythm in a specific place.
Multiple oscillator models refer to which hypothesis?
The hypothesis that there are several groups of neurones, each responsible for different aspects/phases of respiration.
What are the 4 stages of the group pacemaker mechanism hypothesis?
1 Post burst hyperpolarisation - Synapses silent
2 Recover - Endogenous activity resumes
3 Recurrent excitation - Positive feedback
4 Burst - Synaptic excitation evokes intrinsic currents
pBC means what? What is its relevance?
Single oscillator hypothesis is supported (to a degree) by experiments showing this area as a site for respiratory rhythm generation.
It also drives output in the roots of the hypoglossal nerve.
The corticospinal tracts control ____ respiration
The corticospinal tracts control ____ respiration
Voluntary. Voluntary control arises from the motor and premotor cortex and descends in the cord in the corticospinal tract.
The anterior spinal tracts control ___ respiration
Nasal Receptors trigger which reflexes?
Sneeze, Diving Reflex (causes apnoea and bradycardia), coughing, aspiration reflex. Irritant receptors (vagus stim.)
Where are J receptors found and which reflexes are they involved in?
Prob. Alveolar walls, next to capillaries. Engorged capillaries and < interstitial fluid stimulates the Vagus nerve, causing Dyspnoea (SOB) e.g. in Left heart failure.
What happens to ventilation rate as Alveolar Pco2 rises?
Ventilation increases. An increase in Pco2 is STRONGLY correlated with an increase in ventilation.
What constantly adjusts (via chemoreceptors) to match changes in alveolar intake of oxygen and carbon dioxide, and keep the partial pressure(s) of oxyegn and carbon dioxide in the blood within normal limits?
Alveolar ventilation (VA)
What happens to ventilation below 60mmHg PO2?
A BIG and rapid increase in ventilation
A low partial pressure of oxygen stimulates what?
If the partial pressure of oxygen is lower than normal, there is increased sensitivity to raised PCo2. Below 60mmHG, PO2 becomes a very strong stimulus of ventilation.
Metabolic acidosis has what effect on ventilation?
It is a strong driver of ventilation - as pH increases, so does ventilation rate.
Where are the central chemoreceptors found?
Experiments suggest that these are in close proximity to the ventrolateral medulla - some in the medullary raphe, the retrotrapezoid nucleus, and glial cells.
Central chemoreceptors respond to what?
Which chemoreceptors respond to the partial pressure of oxygen?
What are the peripheral chemoreceptors?
These are located in the CAROTID and AORTIC bodies found at the bifurcation of the carotid, and is a separate structure from the artery. They respond rapidly to variations in oxygen (i.e hypoxia), carbon dioxide (hypercapnia), and low glucose (hypoglycemia). HYPOXIA and HYPERCAPNIA are the most heavily studied and understood conditions detected by the peripheral chemoreceptors. Afferent nerves carry signals to the brainstem, which responds accordingly (e.g. increasing ventilation).
What are the peripheral chemoreceptors?
These are located in the CAROTID and AORTIC bodies found at the bifurcation of the carotid, and is a separate structure from the artery. They respond rapidly to variations in oxygen (i.e hypoxia), carbon dioxide (hypercapnia - ESP. FAST RISE IN PCO2), and low glucose (hypoglycemia). HYPOXIA and HYPERCAPNIA are the most heavily studied and understood conditions detected by the peripheral chemoreceptors. Afferent nerves carry signals to the brainstem, which responds accordingly (e.g. increasing ventilation).
How do Glomus cells respond to low PO2?
Low PO2 causes depolarisation of the membrane, causing calcium influx, releasing neurotransmitter, which stimulates 9th nerve to signal to Medulla.
What are the key risk factors for sleep apnoea?
Drinking before bed
Side effects of Metformin?
Can cause kidney failure as a result of lactic acidosis.
Side effects of Amitriptyline?
Side effects of Pregablin?
Fluid retention/weight gain
Side effects of Celecoxib?
Serious Stomach and intestinal ulcers.
What is the biggest indicator of obstructive sleep Apnoea?
A better indicator than BMI (Body mass index)
BUT still large variation - requires clinical assessment.
If you have a patient that has told you they are tired, what important advice should you give?
DRIVING advice - State and RECORD this.
Large fluid effusion in the pericardium may show what on ECG?
Low voltage QRS complex
Large effusion of the pericardium looks like what on a Chest X-Ray?
A Spherical, "round", large looking heart.
What are the differential diagnostic differences between acute CS, PE, and cardiac tamponade
PE - SOB, but sim. risk factors. Different sort of pain to CS. ECG will come back normal (usually).
Tamponade - May see Electrical alternans - Ultrasound to assess chambers and x-ray to assess potential fluid.
Acute coronary syndrome will also have raised Troponins - far greater than other two.
What is pulsus paradoxus?
The exaggeration of a normal response.
Tends to occur in patients with pericardial fluid.
Results in change in pulse during inspiration/expiration as a result of intra-thoracic/pericardial pressure changes.
Feeling brachial pulse - Feels strong, almost disappears on inspiration.
The visceral pericardium is also known as what?
Which two layers make up the serous pericardium?
Visceral (inner) and Parietal (outer)
What is the name given to the pericardial layer surrounding the serous pericardium? What is it continuous with?
Continuous with adventitia of the great vessels
Anchored to diaphragm and posterior surface of the sternum
What does the fibrous pericardium do?
Anchors heart in place - limits how much the heart chambers can fill.
What is the Transverse pericardial sinus
A space between the two layers within the serous pericardium. It allows space for fingers to be placed under and around the great vessels (useful in surgery)
Tamponade is due to fluid between the ___ and ____ pericardium.
Visceral and parietal.
Pain in the heart is referred where?
Afferent fibres from Cardiac plexus enter the spinal tract at about T4. Somatic pain is felt as the brain isn't used to "feeling" visceral pain.
Pain in the pericardium refers through which nerve?
Via Phrenic nerve, referring pain up to C3,4,5 (esp 4) causing pain to shoulder.
Describe the functions of the pericardium
1. Stabilization of the heart within the thoracic cavity by virtue of its ligamentous attachments -- limiting the heart’s motion.
2. Protection of the heart from mechanical trauma and infection from adjoining structures.
3. The pericardial fluid functions as a lubricant and decreases friction of cardiac surface during systole and diastole.
4. Prevention of excessive dilation of heart especially during sudden rise in intra-cardiac volume (e.g. acute aortic or mitral regurgitation).
How much fluid does the pericardium normally contain?
15-50 ml fluid normally.
What are the aetiologies of Pericardial effusion?
1. Inflammation from infection, immunologic process.
2. Trauma causing bleeding in pericardial space.
3. Noninfectious conditions such as:
a. Increase in pulmonary hydrostatic pressure e.g. congestive heart failure.
b. Increase in capillary permeability e.g. hypothyroidism
c. Decrease in plasma oncotic pressure e.g. cirrhosis.
4. Decreased drainage of pericardial fluid due to obstruction of thoracic duct as a result of malignancy or damage during surgery.
Viral pericardial effusion are usually ___ or ___.
Viral effusions are usually serous or serofibrinous
Malignant pericardial effusions are usually ____.
Malignant effusions are usually hemorrhagic.
What is a clinical sign of recurrent laryngeal nerve compression?
What is cardiac tamponade?
Accumulation of pericardial fluid under high pressure compresses cardiac chambers & impairs diastolic filling of both ventricles. This reduces stroke volume, and subsequently cardiac output, leading to congestion, hypotension and shock. A reflex tachycardia may be present.
What are the SIGNS of cardiac tamponade?
rales (small bubbling/clicking sound)/oedema/ascites
muffled heart sounds
pulsus paradoxus (Abnormal > in Sys BP during inspiration)
What are the SYMPTOMS of cardiac tamponade?
Acute: (trauma, LV rupture), profound hypotension
Slow/Progressive large effusion (weeks): Fatigue
Dyspnea (SOB), Jugular vein distension
What is the pre-Botzinger complex?
A cluster of interneurons in the ventrolateral medulla of the brainstem, essential to the generation of respiratory rhythm. The exact mechanism of the rhythm generation remains controversial and the topic of present research.
A section below the pontine respiratory groups will result in what?
A section (cut) below this will have a continuous but abnormal respiratory rhythm.
A section above the pontine respiratory groups will result in what change to respiratory rhythm ?
A section above (usually) leaves a regular respiratory rhythm.
Irritant receptors found between airway epithelial cells conduct which reflex?
Bronchoconstriction via the Vagus nerve, i.e. in response to noxious gases.
Modification of respiratory rhythm is by what?
1.) Other parts of CNS inc. Pontine respiratory group(PRG).
2.) Voluntary control from cerebral cortex to pyramidal tracts to corticospinal tracts (bypass brainstem).
3.) Airway and lung reflexes.
4.) By chemoreceptors.
Why is the control of alveolar ventilation important?
1.) The partial pressure of oxygen in the blood partly affects the rate of oxygen supply to tissues. Alveolar ventilation adjustment maintains PaO2, even when VO" and VCO2 changes.
2.) The partial pressure of carbon dioxide in the blood effects the blood pH - it's important to not let levels rise or fall by too much!
Peripheral chemoreceptors respond about ___% to changes in CO2.
At which spinal level does the aorta begin its descent?
T4 (4th Thoracic vertebrae)
Where are central chemo-receptors (in context of respiration) found?
They are found in the medulla Oblongata - near the ventrolateral surface, and probably in other local sites as well.
What % ventilatory response do central chemoreceptors have to CO2?
What do central chemoreceptors respond to?
They respond to changes in PCO2 (partial pressure of carbon dioxide in the blood), and pH (probably a direct response to CSF pH).
What is the main stimulus for breathing at normal partial pressure of oxygen and carbon dioxide in the blood?
Oxygen can directly stimulate breathing at __ ___
Low PO2 (partial pressure of oxygen in the blood).
Respiratory rhythm comes from which part of the brain?
What is respiratory acidosis?
Respiratory acidosis is a condition that occurs when the lungs cannot remove all of the carbon dioxide the body produces. This causes body fluids, especially the blood, to become too acidic.
What would you expect bicarbonate levels to be in partially compensated respiratory acidosis?
Low (below normal range)
What would you expect bicarbonate levels to be in compensated chronic respiratory acidosis?
Within normal limits - usually occurs with long standing condition I.E COPD.
What is respiratory Alkalosis?
Respiratory alkalosis is a disturbance in acid and base balance due to alveolar HYPERVENTILATION. Alveolar hyperventilation leads to a decreased partial pressure of arterial carbon dioxide (PaCO2). In turn, the decrease in PaCO2 increases the ratio of bicarbonate concentration to PaCO2 and, thereby, increases the pH level, thus the descriptive term of respiratory alkalosis.
Sensation from the pericardium is supplied by which nerves?
The phrenic nerves.
The recurrent laryngeal nerves are "offshoots" from which nerves?
The vagus nerves.
Why may pericarditis be reffered to the shoulder tip?
There is common innervation (C3, 4, 5).
Think: C3,4,5 keeps Diaphragm alive. Most of the time there isn't any sensation from diaphragm. but a nearby organ may irritate the diaphragm (as in pericarditis), causing sensory fibers of one of the phrenic nerves to flood with pain signals that travel to the spinal cord (at C3-C5). It turns out that C3 and C4 don't just keep the diaphragm alive; neurons at these two spinal cord levels also receive sensation from the shoulders (via the supraclavicular nerves). So when pain neurons at C3 and C4 sound the alarm, the brain assumes (quite reasonably) that the shoulder is to blame.
To what does the term "Pickwickian Syndrome" refer?
Obesity hypoventilation syndrome (also known as Pickwickian syndrome) is a condition in which severely overweight people fail to breathe rapidly enough or deeply enough, resulting in low blood oxygen levels and high blood carbon dioxide (CO2) levels. Many stop breathing altogether during sleep (obstructive sleep apnoea), resulting in many partial awakenings during the night, which leads to continual sleepiness during the day.
What are the symptoms of Obstructive Sleep Apnoea?
Loud snoring (95%)
Daytime sleepiness (90%)
Unrefreshed sleep (40%)
Restless sleep (40%)
Morning headache (30%)
Nocturnal choking (30%)
Reduced libido (20%)
Morning drunkenness (5%)
Ankle swelling (5%)
Say everything you can about the a wave of the JVP
First positive presystolic a wave is due to right atrial contraction. 2.) Effective RA contraction is needed for visible a wave. 3.) Dominant wave in JVP and larger than v wave. 4.) It precedes upstroke of the carotid pulse and S1, but follows the P wave in ECG.
Say everything you can about the x descent of the JVP
1.) Systolic x descent is due to atrial relaxation during atrial diastole 2.) X descent is most prominent motion of normal JVP which begins during systole and ends just before S2. 3.) It is larger than y descent. 4.) X descent more prominent during inspiration.
Say everything you can about the c wave of the JVP
Not usually visible.
Two different causes if seen:
- Transmitted carotid artery pulsations.
- Upward bulge of closed Tricuspid valve in
Say everything you can about the X' descent of the JVP
x`descent is systolic the trough after the c wave.
Due to: 1.) Fall of right atrial pressure during early RV systole. 2.) Downward pulling of the TV by contracting right ventricle. 3.) Descent of RA floor.
Say everything you can about the v wave of the JVP
1.) Begins in late systole and ends in early diastole.
2.) Rise in RA pressure due to continued RA filling during ventricular systole when tricuspid valve closed.
3.) Roughly synchronous with carotid upstroke and corresponds S2.
Say everything you can about the y descent of the JVP
1.) Diastolic collapse wave (down slope v wave)
2.) It begins and ends during diastole well after S2.
3.) Decline of RA pressure due to RA emptying during early diastole when tricuspid valve opens.
Obesity hypoventilation syndrome is otherwise known as what?
Would you use cardioversion if you can feel a pulse?
Yes - but it would be planned - if there is no need for a defibrillator, do not use it!
Which colour vacutainer do you use for a full blood count?
Which colour vacutainer do you use for biochemical tests?
Which colour vacutainer do you use for tests of coagulation?
AUMB WALES Order of draw for blood collection by colour is what?
When describing a pneumothorax on an X-Ray - how could you justify that pneumothorax is correct? Two points.
1.) Clearly defined lung edge.
2.) Air space clearly visible beyond lung edge.
What is respiratory failure?
Respiratory failure is inadequate gas exchange by the respiratory system, with the result that levels of arterial oxygen, carbon dioxide or both cannot be maintained within their normal ranges. A drop in blood oxygenation is known as hypoxemia; a rise in arterial carbon dioxide levels is called hypercapnia.
What is Type 1 Respiratory failure?
Type 1 respiratory failure is defined as hypoxemia (Low PO2) without hypercapnia, and indeed the PaCO2 may be normal or low. It is typically caused by a ventilation/perfusion (V/Q) mismatch; the volume of air flowing in and out of the lungs is not matched with the flow of blood to the lungs.
What is Type 2 respiratory failure?
Hypoxemia (PaO2 6.0kPa).
Type 2 respiratory failure is caused by inadequate alveolar ventilation; both oxygen and carbon dioxide are affected. Defined as the build up of carbon dioxide levels (PaCO2) that has been generated by the body but cannot be eliminated.
What is the difference between Type1 and Type2 respiratory failure?
Type one is a drop in bothPO2 andPCO2 - Type two is a drop in PO2 and a rise in PCO2. Type 2 tends to be far more worrying!
What happens to the pH of blood int ype 2 respiratory failure?
pH drops - Acidotic
Mycoplasm pneumonia can cause what?
Muscle damage and lung weakness/failur
What (usually) causs Type1 respiratory failure?
This type of respiratory failure is caused by conditions that affect oxygenation such as:
1.)Low ambient oxygen (e.g. at high altitude)
2.) Ventilation-perfusion mismatch (parts of the lung receive oxygen but not enough blood to absorb it, e.g. pulmonary embolism)
3.) Alveolar hypoventilation (decreased minute volume due to reduced respiratory muscle activity, e.g. in acute neuromuscular disease).
4.) Diffusion problem (oxygen cannot enter the capillaries due to parenchymal disease, e.g. in pneumonia or ARDS)
5.) Shunt (oxygenated blood mixes with non-oxygenated blood from the venous system, e.g. right-to-left shunt).
What (usually) caues Type 2 Respiratory failure?
The underlying causes include:
1.) Increased airways resistance (chronic obstructive pulmonary disease, asthma, suffocation)
2.) Reduced breathing effort (drug effects, brain stem lesion, extreme obesity)
3.) A decrease in the area of the lung available for gas exchange (such as in chronic bronchitis)
4.) Neuromuscular problems (Guillain-Barré syndrome, myasthenia gravis, motor neurone disease)
5.) Deformed (kyphoscoliosis), rigid (ankylosing spondylitis), or flail chest.
If your lug volume drops by 20% or more when lying flat, what is indicated?
Muscle weakness i.e. diaphragmatic weakness.
A man presents with astrange symptom - he gets breathless when he gets in and out of the swimming pool...what's going on?
Phrenic nerve palsy - diaphragmatic muscle weakness. When he gets in the water, abdominal viscera comress lung volume!
A patient presents acidotic, bicarb of 35, PCO2 high and PO2 low - what is this?
Acute on chronic Type 2 respiratory failure. Bicarbonate is compansating forchronic condition, but acidotic indicates acute respiratory failure.
Define sleep Apnoea.
Stopping (or slowing) breathing during sleep due to obstruction (narrowing) of the upper airway.
What is the incidence of OSA?
3-5% of men nd 1-2% of women have OSA worthy of treatment (around 88% of which are undiagnosed!)
What is the aetiolgy of obstructive sleep Apnoea?
Pharyngeal incompetence brought on by sleep. Recurrent brief arousal from sleep to clear the airway. Prevention from REM sleep means ptx will feel exhausted regardless of time spent in bed. This can cause daytie consequences - mainly daytime sleepiness.
What are the risk factors for Obstructive Sleep Apnoea Hypopnoea syndrome?
Obesity,Tonsils, Hypothyroid, Smoking, Acromegaly, Mucopolysaccharidoses, nasal problems, Alcohol/sedatives, Menopause, Neuromuscular disease/stroke
Obstructive Sleep Apnoea is more common in ___.
Men! 4:1 - can go to10:1
What are the key symptoms of OSA during the day?
Sleepiness, morning headaches, dry throat, poor concentration,irritabilitanxiety/depression, loss of libido.
What are the symptoms of OSA during the NIGHT?
Snoring, choking, Apnoeas, Sweats, Restless sleep, Vivid dreams, Nocturia.
What thngs would you examine specific to OSA?
Collar size, BMI, Upper Airway,BP, ESS (often co-morbidity)
OSAHS is lited as the commonest cause of ____ _______.
Explain the acronym "Definitely, i a surgeons gown a physician might make some progress"
Definition, Incidence, Aetiology, Sex, Geography,Ag, Presentation, Prognosis (treatment).
Used to be popular - not anymore! Removal of the palate totry an help OSA - Evidence does not support.
The diagnosis of sleep apnoea is confirmed if there are more than _____ apnoeas recorded in an hour.
The diagnosis of sleep apnoea is confirmed if there are more than 10-15 apnoeas recorded in an hour.
In the 50% of OSA patients that cannot tolerate CPAP, what alternative is used?
Modafinil - short term.
Type 1 Respiratory failure presents with either normal pH or ____.
In restrictive lung disease both ___ and ___ are reduced due to reduced ____ ______.
In restrictive lung disease both FEV1 and FVC are reduced due to reduced lung capacity.
What could cause restrictive lung disease if a patient has chronic liver disease?
Which neurological disorder can cause type 1 respiratory failure?
Glycogen containing vacuoles, muscle fibrils suggest what?
Acid maltase deficiency.
Acid maltase deficiency is confirmed by what?
Maltase enzyme assay in muscles, fibroblasts or WBCs, Glycogen granules in lymphocytes (PAS)
Acid maltase deficiency is a defect of ____ enzyme.
What are the three types of acid maltase deficiency?
INFANTILE: (Pompe’s) Resp failure and usually death < 2 years
JUVENILE: Limited survival
ADULT: Best prognosis
Name 4 restrictive lung diseases.
Name three pleural diseases that can cause restrictive lung disease.
Name three chest wall deformity diseases that may cause restrictive lung disease?
Name two causes of respiratory muscle weakness.
Define Obstructive sleep Apnoea (OSA)
Stopping (or slowing) breathing during sleep due to
obstruction (narrowing) of the upper airway
At what age is the peak presentation for OSA?
Which chronic diseases are commonly associated with OSA?
Average use (hours per night) of CPAP is what?