Respiratory

• Ventilation and Respiration
• To deliver and remove gases

In the brainstem, the medulla oblongata and the pons are involved in ventilation

Ventilation

Respiration

The right lung is larger and heavier than the left because it has an upper, middle, and lower lobe

The left lung only has an upper and lower lobe

Pleura

There are two pleural surfaces separated by an airtight space taht contains a thin layer of lubricating fluid

This lubricating fluid allows the two pleural membranes to glide against each other during inhalation and exhalation

The pleural space has a pressure within it called intrapleural pressure that differs from the pressure in the lungs and atmospher pressure

The constant pull of the two pleural membranes in opposite directions causes the pressure within the space to be below atmosphere...this negative pressure in the pleural space keeps the lungs inflated

If atmosphere pressure enters the pleural space, all or part of a lung will collapse, producing a pneumothorax

• The intrapleural pressure is less than lung and atmosphere pressure
• The constant pull of the two pleural membranes in opposite directions during ventilation is what causes this subatmospheric or negative pressure

The negative pressure in the pleural space

All or part of a lung will collapse, producing a pneumothorax

Muscles that increase the size of the chest are called muscles of inhalation

Muscles that decrease the size of the chest are called muscles of exhalation

• The diaphragm
• The diaphragm separates the thoracic and abdominal cavities
• Because it does most of the work of inhalation, trauma involving levels C3 to C5 causes ventilatory dysfunction

On inhalation, the diaphragm contracts and flattens, pushes down on the viscera, and displaces the abdomen outward

• The intercostal muscles
• These muscles elevate the ribs and expand the chest cage outward

• The diaphragm relaxes and moves back up toward the lungs
• Because exhalation is a passive act, there are no true muscles of exhalation.
• However, during exercise exhalation becomes a more active event, requiring some participation of the accessory muscles of ventilation.

• Scalene
• Sternocleidomastoid
• Other chest and back muscles such as the trapezius and pectoralis major

• The upper airways
• The trachea
• Bronchial tree

• To warm and humidigy the inhaled air
• To act as a protective mechanism that prevents the entrance of foreign matter into the gas exchange areas
• To serve as a passageway for air entering and leaving the gas exchange regions of the lungs

• Nasal and oral cavities
• Pharynx
• Larynx

• Conditioning of inspired air
• *Conditioned air is air that has been warmed, humidified, and cleansed of some irritants
• *Warming and humidifying, which are essential to prevent irritation of the lower airways, occur mainly within the nose by means of a dense vascular network that lines the nasal passages
• *The air is cleaned by the coarse hairs that line the nasal passages and filter large inhaled particles

Epiglottis

Carina

The two main stem bronchi arise from the carina

• Carina
• The carina is an important landmark during endoscopy of the bronchial tree

• The left bronchus is smaller and narrower than the right because the heart needs room, it angles directly toward the left lung
• The right bronchus is wider and has a sharper angle. This position along with the forces of gravity is the reason the right side is the most common site of aspiration of foreign objects

Through the right main stem bronchus into the lower lobe of the right lung

• Trachea
• Bronchial tree

• Respiratory bronchioles
• Alveoli
• Gas exchange takes place in these areas of the lungs

• Mucous blanket which is a combination of mucus and cilia
• The mucus floats on top of the cilia and traps foreign particles
• Ciliary movement then propels the entire mucous blanket and any trapped particles upward toward the pharynx to be swallowed or cleared
• The cough reflex is another protective mechanism in the lungs. Excessive amounts of foreign particles in the trachea and bronchi can initiate the cough reflex

• Alveoli
• The alveoli are the primary site of gas exchange and the end of the respiratory tract

• Surfactant
• Surfactant lowers surface tension of the alveoli
• Within the lungs, surfactant stabilizes the alveoli, increases lung compliance, and eases the work of breathing

• Lower surface tension of the alveoli
• Increases lung compliance
• Eases the work of breathing

• Lungs become less compliant and the work of breathing increases
• Severe loss of surfactant results in alveolar instability and collapse and impairment of gas exchange

Goblet cells

In the bronchioles

In the respiratory bronchioles

The lung will collapse, also called a pneumothorax

• Their walls are made up of smooth muscle instead of connective tissue and cartilage
• When constriction occurs, these airways may close completely because of the lack of structural support

• 4
• Acidic

Alveoli are only one cell membrane thich which presents no barrier to diffusion

• The difference between intrapulmonary pressure (pressure inside the lungs) and atmospheric pressure
• When the pressure falls below atmospheric pressure, air enters the lungs (inhalation)
• At the end of inhalation, the muscles of ventilation relax, the thorax contracts and the lungs are compressed, and intrapulmonary pressure rises
• When the pressure rises above atmospheric pressure, air exits the lungs (exhalation)

• *Elastic properties are determined by:
• Lung recoil
• Chest wall recoil
• Surface tension of the alveoli

• *Resistive properties are determined by:
• Airway resistance

*Normally, the work of breathing occurs during inhalation, but even exhalation can be a strain when lung recoil, chest wall recoil, or airway resistance is abnormal

Pulmonary diseases that decrease lung compliance (ex:atelectases, pulmonary edema), decrease chest wall compliance (ex:kyphoscoliosis), increase airway resistance (ex:bronchitis, asthma), or decrease lung recoil (ex:emphysema) can increase the work of breathing so much that one third or more of the total body energy is used for ventilation. Nutrition is important to maintain energy. We supplement oxygen so patients do not have to work so hard to breath

• Restrictive diseases
• OR
• Obstructive diseases

• *Depends on how the underlying cause affects normal ventilation
• *Some people may have both types
• *Normal muscular action of the diaphragm, flexibility of the rib cage, elasticity of the lungs, and airway diameter are key in allowing easy inhalation and exhalation. Any interference with these actions impairs normal ventilation

• Restrictive diseases
• Can be acute or chronic
• Because they restrict lung or chest wall expansion, or both, patients have smaller tidal volumes but an increased ventilatory rate to maintain minute ventilation

• Obstructive disease
• Classic examples are emphysema and asthma
• In emphysema, airflow is decreased because of a decrease in lung recoil which results in lungs that inflate easily but, do not compress to assist with exhalation because the normal elastic recoil is not there
• So patients with emphysema may have no trouble inhaling, but struggle to exhale
• In asthma, airflow is decreased because of diffuse airway narrowing

• Volumes and Capacities:
• Tidal volume
• Inspiratory reserve volume
• Expiratory reserve volume
• Residual volume
• Inspiratory capacity
• Functional residual capacity
• Vital capacity
• Total lung capacity

Tidal volume (V_T)

• Inspiratory reserve volume (IRV)
• So when you breath in as far as you can, then force more air in the lungs is the IRV

• Expiratory reserve volume (ERV)
• So when you exhale as much as you can, then force more air out of the lungs is the ERV

Residual volume (RV)

• Funtional residual capacity (FRC)
• So when you take the maximum amount of air that can be exhaled + the amount of air left in the lungs after, you get the FRC

• Vital capacity (VC)
• So when you take the maximum amount of air inhaled + the amount of air inhaled and exhaled with each breath + the maximum amount of air exhaled =VC

Total lung capacity (TLC)

Total lung capacity (TLC)

• Dead space regions
• So air is getting into the areas (ventilated), but the alveoli are not being perfused with blood.
• Without perfusion, gas exchange cannot take place, and the ventilation is wasted

Air cant get in or out

• Diffusion
• Diffusion moves molecules from an area of high concentration to an area of low concentration
• The difference in the concentrations of the gases is referred to as the driving pressure
• The greater the driving pressure of the gas through the membrane, the greater the rate of diffusion

• Pulmonary capillaries and the alveoli
• Oxygen is in high concentration within the alveoli and moves by diffusion from the alveoli into the pulmonary capillaries
• Carbon dioxide is in higher concentration within the pulmonary capillaries; therefore, carbon dioxide diffuses out of the capillaries into the alveoli where it is exhaled

• The thickness of the alveolar capillary membrane (ex:pulmonary edema, fibrosis)
• The surface area of the membrane (ex:pneumonectomy, lobectomy, pulmonary embolus, emphysema all decrease the rate of diffusion)
• The diffusion coefficient of the gas (is determined by its solubility and carbon dioxide diffuses more rapidly than oxygen)

• Normally, alveolar ventilation is about 4L/min and pulmonary capillary perfusion is about 4 L/min
• So the normal ventilation/perfusion ratio (V/Q) is 4:5
• The distribution of ventilation throughout the lungs is not even as a result of factors such as the shape of the thorax and the effects of gravity on intrapleural pressure.
• The distribution of perfusion through the lungs is related to gravity and intraalveolar pressures

• At one end of the continuum, the alveolus is receiving ventilation but is not receiving any perfusion and is unable to participate in gas exchange (alveolar dead space)
• On the other end of the continuum, the alveolus is receiving perfusion but is not receiving any ventilation and is unable to participate in gas exchange (intrapulmonary shunting) in this case, the blood is returned to the left side of the heart unoxygenated
• In between the two there are an infinite number of ventilation/perfusion mismatches
• Although minor mismatching of ventilation may not significantly affect gas exchange, significant alterations in the relationship results in hypoxemia

Hypoxemia

Dead space producing

• Intrapulmonary shunting
• In this case, the blood is returned to the left side of the heart unoxygenated

• Hypoxic vasoconstriction
• This event is thought to be a compensatory response used to limit the return of unoxygenated blood to the left side of the heart.
• If the response is prolonged and generalized throughout the lungs, pulmonary hypertension will result

Pulmonary hypertension

4

• Inhale CO instead of O2
• CO clings to hemoglobin for a long time
• Decreases cilla action
• Mast cells are stimulated
• The break down and release of mediators cause an inflammatory response which causes edema and contraction of smooth muscles
• There is a decrease in surfactant secretion which is important to keep alveoli open
• There is an increased release of protease which eventually exhausts the release of antiprotease
• Alveolar destruction causes inflammation and they loose elasticity

Using more than q48 hrs can cause rebound inflammation

21%

The adequacy oxygenation/ventilation and circulation

• 7.35-7.45
• Decreases with aging from 60-90yrs the normal is 7.31-7.42

7.31-7.42

Buffers

Respiratory rate

Kidneys

AlKalosis Kicks up pH

AciDosis kicks Down pH

• 35-45
• PCO2 increases with aging
• Co2 travels in the blood as carbonic acid to the lungs where it is exhaled
• So when pH is up, Respirations increase

• pH is 7.35-7.45
• PCo2 is 35-45

• 80-100
• Decreases with age
• The partial pressure O2 in blood is the amound of oxygen dissolved in plasma
• It is the amount of O2 waiting in line to attach to hemoglobin
• Oxygen can only be carried by hemoglobin

pH

• 21-28
• It is the bicarbonate ion concentration in the blood
• It is the renal response to acid base balance that takes days to correct

• -2 to +2
• It is the nonrespiratory contribution to acid base balance

• Base excess and Base deficit
• This is the amount of blood buffers in the blood and is a non-respiratory response to acid base balance

metabolic acidosis

metabolic alkalosis

• 95% or higher
• It is the % of oxygen bound to hemoglobin

• Anemia
• Vasoconstriction

Respiratory Acidosis

• COPD
• Pulmonary Emboli/Edema
• Splinting
• Opiate Overdose
• Asphyxia

Respiratory Alkalosis

• Anemia
• Anxiety
• Fever
• Sepsis

Rebreath CO2 in a bag

• pH and PCO2
• The 2P's

pH and HCO3

• Done at the bedside for the removal of fluid or air from the pleural space
• Can be used as a diagnostic tool or may also be performed therapeutically for the drainage of a pleural effusion or empyema
• Patient is placed in a sitting position with legs over the side of bed with hands and arms supported on a table

• Preoperative assessment
• Evaluating lung mechanics
• Diagnosing and tracking pulmonary diseases
• Monitoring therapy
• Results are individualized according to age, gender, and body size

• When a serious alteration of the normal V/Q relationship is suspected
• It consists of a ventilation scan and a perfusion scan
• Helps determine if the problem is heart or lung related
• Ordered most often to diagnose and follow a suspected PE
• Only 90% accurate diagnosing PE so use clinical assessment

• The ventilation scan is done by having the patient inhale a gas and air mixture
• The perfusion scan is done by injecting the patient with a radioisotope

• Thoracic cage: there should be no evidence of fractures, etc
• Mediastinum:trachea should be midline
• Diaphragm: should be clearly visible at the 10th rib
• Pleural Space: Should not be visible at all
• Lung Tissue: viewed for any areas of increased density
• Wires etc: assessed for proper placement of tubes, wires, and lines

In any situation that requires continuous observation

• ARDs is usually caused by another disorder that has altered the normal function of the pulmonary system such as smoke inhalation, oxygen toxicity, chemicals, trauma, etc
• Because these disorders damage the alveolar capillary membrane, the lungs cannot exchange gas sufficiently to oxygenate the blood

• emPhysema has the letter P
• Bronchitis has the letter B

• ABCDE
• Asthma
• Bronchiectases
• Chronic bronchitis
• Dyspnea or Decreased FEV/FVC
• Emphysema

PEEP

control ventilation

• Manual resuscitation bag and mask
• Obturator

10 times/hr

If the tube is dislodged accidentally, the initial nursing action is to grasp the retention sutures and spread the opening