Pulmonary

Pleura

Between muscle and lung

Pleur-Evac Drain

Collects fluid from pleur space and capable of providing suction

Common place to place chest tube?

Between fourth and fifth rib

Paradoxical breathing

Chest wall moves INWARD during inspiration and OUTWARD during expiration (i.e. opposite of normal)

What is paradoxical breathing caused by?

severe COPD, lung hyperinflation, trauma, diaphragm paralysis

Lung hyperinflation

Air trapped in lungs that doesn’t escape well, causing a flattened diaphragm

Flail chest

Double fractures of 3+ adjacent ribs

Pathological fracture

Break of bone weakened from a disease process that would not have otherwise expected to result in fracture (e.g. from osteoporosis)

Dysphagia

Difficulty in swallowing

Importance of proper epiglottis function

-facilitate increase in intrathoracic pressures needed for effective cough

-prevent aspiration of food, liquid, foreign objects

The further down you go the respiratory tract, the ____ cartilaginous support there is

Less

Atelectasis

Portion of alveoli in lungs collapse

The respiratory zone is supported by

Airflow

The upper airway is considered the ____, middle airway is ____, and lower airway is ____

Trachea, bronchi + bronchioles, alveolar sacs + ducts

Acute Respiratory Distress Syndrome (ARDS)

Damage to ALVEOLAR CAPILLARY MEMBRANE can cause blood vessel leakage into alveolar sacs

Angle of primary bronchi bifurcation for R lung

Right primary bronchus is wider, shorter and more vertical

What lung is more likely to get aspiration pneumonia?

Right lower lung

Aspiration Pneumonia (PNA)

Inflammatory process of lung tissue from inhalation of a foreign object

Viral/covid pneumonia secretion in airway

No secretions in airway (dry cough)

Bacterial pneumonia

Lots of secretion in airway (wet cough)

-NOT in alveolar sac → in airway

Pulmonary Edema

Secretion in the alveolar sac (coughing will not clear this)

Pleural Effusion

Fluid in pleural space

To drain the R upper lobe, how do you lay down?

Left sidelying

To drain the L upper lobe, how do you drain it?

Have pt lay down at a 45 degree bed angle on tummy

SNS + PNS input on airway resistance

SNS - dilation (T1-5)

PNS - constriction (vagus)

Laminar vs Tansitional vs Turbulent flow

-Laminar: parallel w tube, no resistance

-Transitional: local eddies at bifurcation

-Turbulent: lots of eddies, often high flow rates or obstruction like mucus plugging or bronchoconstriciton

Highest airway resistance order

Middle airways, uppermost airways, lowermost airways

Respiration vs ventilation

-Respiration: process of gas exchange in the lungs through simple diffusion

-Ventilation: mechanical movement of gases in and out of lungs

Mechanics of inspiration

Atmospheric pressure > alveoli = air in

Mechanics of Expiration

Alveoli pressure > atmospheric pressure = move air out

Pump handle inspiration

Increases AP diameter, superior and anterior sternal movement

Bucket handle inspiration

Increases transverse diameter, lateral elevation ribs

Subcostal angle

-90 degrees, btwn R and L borders of rib 7-10 /c xiphoid process @ apex

With inspiration, subcostal angle _______, with expiration, it ______

Increases, decreases

If you have COPD, how does that affect the subcostal angle?

At rest angle will be greater

Primary muscle of inspiration

Diaphragm, eternal intercostals

Accessory Muscles of Inspirtion (use /c exertion or distress)

SCM, scalenes, UT, pec major and minor, SA, lags

Expiration muscles

-normal = elastic recoil

-accessory = abdominals, internal intercostals

What part of the medulla is used for inspiration and what type of inspiration does it do?

Dorsal medulla → rate, rhythm, depth

What part of the medulla is used for forced exhalation and what does it do?

Ventral medulla → inhibit inspiration center when forced/deep expiration is needed

2 part of automatic breathing of the pons

Pneumotaxic center, apneustic center

Pneumotaxic Center

-upper pons

-modulate timing of inspiration and expiration (IR)

What can the Pneumotaxic center inhibit?

Inspiratory center (dorsal medulla) or apneustic center

Apneustic center

-facilitates prolonged breathing patterns

-lower pons

When is the apneustic center used more?

When upper pons has been impacted by a injury or lesion

Where do changes for voluntary breathing occur?

Motor cortex → bypasses respiratory centers in brainstem

Joint and muscle receptors in breathing functions

-detect changes in muscle tension and length

-send sensory input to medulla

-increased ventilation during exercise

Where do pain and emotional inputs come from?

Limbic system and hypothalamus

3 types of lung receptors

Irritant, stretch, and j receptors

Where are irritant receptors found and what does they do?

-conducting airways (upper)

-causes cough w exposure to bad gasses/irritants → vasoconstriction and increased RR

Where are stretch receptors found and what does they do?

-smooth muscle lining of airways (middle)

-inhibit inspiration w increased volume, protect from hyperinflation

Where are j receptors found and what do they respond to?

-alveolar walls

Increased pulmonary capillary pressure and interstitial fluid accumulation

What are chemoreceptors responsible for?

Changing RR in response to changes in pH, PO2, and PCO2 levels

Where are chemoreceptors located (centrally and peripherally)?

Central → upper medulla

Peripheral → aortic arch + carotid artery

What are central chemoreceptors sensitive to?

Changes in PaCO2 (medullary → H+)

What does conversion of H+ in central chemoreceptors promote?

Medullary stimulation → lowers pH, stimulates increase in RR to blow off PCO2

What changes are peripheral chemoreceptors sensitive to?

PaO2

By how much do PaO2 levels have to drop if PaCO2 levels are normal before stimulating increases in ventilation?

55-60 mmHg

O2 dissociation curve

Relationship between available O2 (PaO2) and degree (%) of saturation of Hg (SpO2)

80-100mmHg of PO2 =

95+% SO2 levels (good!)

What is COPD caused by?

Chronic and prolonged hyperecapnia (high PaCO2) → desensitized central chemoreceptors in response of elevations in CO2

What can cause a right shift in O2 dissociation curve?

-increase temp, hypoxia, increased CO2, increased acidosis → oxygen unloads more easily

What can cause a left shift in the O2 dissociation curve?

-decreased temp, decreased CO2, alkalosis → more difficult for oxygen to be used

What is pleural pressure? What is the pressure?

Pressure between lung and inside of chest cavity

-negative pressure, 5cm H2O

Where is intrapleural pressure greater?

Top of lung (due to weight of suspended lung)

What is surfactant?

Lipoprotein the lines alveoli to reduce surface tension of alveoli to collapse forward

Where is surfactant needed more in the lung?

Base of the lung (to equalize resistance at bottom are air goes into larger top ones more)

What is compliance of the lung?

Ease of stretch during inspiration

What are 3 things compliance of the lung is dependent on?

1. Elastic recoil of lung → pulling inward

2. Surface tension of alveolar fluid

3. Elasticity of thoracic wall → pulling outward

Emphysema vs fibrosis

Emphysema → high compliance, can’t get air out, don’t need to breathe in a whole lot to see change

Fibrosis → doesn’t stretch well, can’t get air in, leads to increased energy expenditure

What is normal V/Q? Which one is higher?

0.8

-V=4L/min, Q=5L/min

What will abnormal V/Q cause?

Hypoxia

Dead space vs shunts in abnormal V/Q

-Dead space (increased): regions w greater ventilation compared to perfusion

-Shunts (decreased): regions w greater perfusion compared to ventilation

Where are blood flow and ventilation most greatest at in the lung?

At the base of the upright lung

Is the base of the lung more likely to have dead space or shunt?

Shunt → perfusion > ventilation

Is the apices of the lung more likely to have dead space or shunt?

-dead space → ventilation > perfusion

When standing upright, where is distribution of perfusion seen the most?

Base

When in supine, where is distribution of perfusion seen the most?

Apical + basal perfusion becomes equal posteriorly

When in sidelying, where is distribution of perfusion seen the most?

Dependent (lowermost) lung is better perfumed

Where is ventilation best in the base of the lung?

Upright

Where is ventilation best in the anterior halves of the lung?

Supine

Where is ventilation best in the posterior halves of the lung?

Prone

4 primary causes of hypoxemia

1. Hypoventilation

2. Diffusion Impairment

3. Anatomical Shunt

4. Ventilation Perfusion Inequality

Hypoxia vs Hypoxemia

Hypoxia→SpO2 (i.e. saturation)

Hypoxemia → PO2

What is hypoventilation?

Inability to adequately ventilate (gas exchange impaired)

What is hypoventilation an increase of and what diagnoses is this seen in?

-Increase in PaCO2 in alveoli → drop in pH → acidosis

What is the treatment of hypoventilation?

100% O2 breathing treatment

What is diffusional impairment?

-does not cross basement membrane well due to thickening of alveolar-capillary barrier (hypoxemia w increased activity)

What test can diffusional impairment be assessed with?

DLCO (diffusional capacity for carbon monoxide)

Diagnoses with diffusional impairment and tx options

-asbestos, interstitial fibrosis, sarcoidosis

-breathing 100% O2

What is rate of diffusion?

Pressure difference between the 2 ends of the diffusion pathway (alveoli and pulmonary capillary)

What is an anatomical shunt?

Unoxygenated blood to mix with oxygenated blood resulting in creased arterial PO2 (unoxygenated blood will not make it to lungs, therapy will not help)