Download Pulmonary Disease

Pulmonary Disease
NFSC 470
McCafferty
Components of the Respiratory System
I. Drive Mechanism
II. Pumping Mechanism
III. Gas Exchange Organs
I.
Drive Mechanism
A.
B.
C.
Controls breathing patterns
Sensitive to hypoxia and hypercarbia
Modulated by the CNS
1.
2.
Brainstem governs automatic respiration
Cerebral cortex controls voluntary breathing
II.
Pumping Mechanism
A.
B.
Air flows in/out as volume of thoracic cavity
changes
Regulated by 3 groups of muscles:
1.
2.
Diaphragm: major muscle for inspiratory
respiration. Moves up or down to lengthen or
shorten cavity. (Inspiration: diaphragm contracts
to increase volume of thoracic cage).
Intercostal muscles: internal & external muscles
connecting ribs. Contract to pull ribs up and out to
increase thoracic diameter
a.
b.
Major role in transition from inspiration to expiration
Provide major muscular work when demands for
ventilation increase
3. Accessory muscles: elevate and stabilize chest
wall at its largest diameter (once already “open”).
Increases efficiency of diaphragm. Active during
heavy breathing.
Also…
5. Chest wall assist with inspiration
6. Abdominals: used in active exhalation, ie.
Exercise. Also role in inspiration
Inspiration is usually active – major role in pumping
mechanism.
Expiration is usually passive.
III. Gas Exchange Organs
A.
B.
Upper airway (nose, mouth, pharynx)
conducts air and keeps out large particles
Lower airway (larynx, trachea, bronchi,
bronchioles, alveolar ducts, and alveoli)
1.
2.
3.
O2 thru alveolar membrane  capillary membrane
 Hgb  tissues
CO2 thru capillary membrane  alveolar
membrane  through bronchial membrane
exhaled
Alveolar membrane produces surfactant (PL):
decreases surface tension and tendancy of
collapse.
Functions of the Respiratory System
I.
II.
III.
IV.
Gas exchange
Speech
Cardiovascular
Metabolic Functions
I.
Gas Exchange
A.
B.
C.
II.
Normal: 15x/min, 500 ml air, therefore
ventilate ~ 11000L air/day
~6000 L blood moves through per day
~600 L O2 in and 460 L CO2 removed
Speech
Thoracic cage supplies exhaled air to voice
apparatus (larynx)
III. Cardiovascular
Nature of lung inflation affects pressure in
thoracic cage; can affect heart i.e. pulmonary
edema
IV. Metabolic Functions
A.
B.
C.
Surfactant production
Formation of angiotensin-converting enzyme
(ACE)
Endothelial cells: produce SOD enzymes
Definitions
I. Partial Pressure: used to indicate the amount of
any gas in the atmosphere, alveoli, or plasma
A. PCO2 Partial Pressure of carbon dioxide
1. Normal arterial blood values = 35-45 mm Hg
2. Normal venous blood values = 41-51 mm Hg
B. PO2 Partial Pressure of oxygen
1. Normal arterial blood values = 80-100 mm Hg
2. Normal venous blood values = 35-40 mm Hg
C. Arterial blood preferred: oxygenated, coming from the
heart
1. Gives idea of how things are throughout the body
2. Gives idea of how well lungs have oxygenated the blood
Note: PCO2 measures respiratory status
↑ PCO2 means poor respiratory function
↓ PCO2 means hyperventilation
II. Respiratory Failure
A. Obstructive
B. Restrictive
Symptoms:
Effects of Respiratory Ds. On
Nutritional Status
I.
intake (see previous slide)
II.
Medications
Steroids (anti-inflammatory) cause protein
catabolism, gluconeogenesis, muscle
wasting and neg. N balance.
IV. Constipation/diarrhea
Choice of low fiber foods (2’ dyspnea); poor peristalsis
2’  O2 to GI tract.
Respiratory Complications:
Malnutrition
I.
Established:
A.
B.
C.
II.
 respiratory muscle structure and fx.
 ventilatory drive
 pulmonary host immune defenses
( susceptibility to infections)
Proposed:
A.  surfactant production
COPD: Chronic Obstructive Pulmonary
Disease
Chronic Obstructive Pulmonary Disease
Slow, progressive obstruction of airways


Maj. Causes: tobacco smoke,
environmental pollution, genetic
susceptibility
Emphysema: lung ds. characterized by
Pts present older, thin, mild hypoxemia but
NL HCT values. Cor pulmonale develops
later
Cron. Bronchitis:
pts NL wt to ovrwt, hypoxemia and  HCT
Cor pulmonale develops early.
Cor Pulmonale:
MNT
Assessment: %IBW alone not sufficient;
ongoing assessment of LBM
Kcals: replete but don’t overfeed!
Indirect calorimetry if possible: Kcal needs
have been observed to range from 94% to
146% of predicted
Respiratory Quotient
Amount of CO2 produced/amount of O2
consumed…
For glucose:
For fat:
For protein:
RQ for conversion of glucose to fat
Prot

Preserve lung, muscle, and immune fx
To preserve appropriate RQ:

Prot:

Fat:
 CHO:
Micronutrients
Smokers :
Mg and Ca imp in muscle
contraction/relax, Mg and Phos monitored
Poss vit D&K
Respiratory rehab: exercise, fluids, easily
chewed diet w/adequate fiber  GI
motility
If experiencing bloating, decrease
gaseous foods.
To  intake





Prevent aspiration:
TF to  kcals in some pts (aspiration issues)
Issues of O2 use at nighttime (overnight
feedings). O2 consumption decreases by 15%25% during sleep.
Respiratory Failure
Causes:
 MODS
ARDS
Respiratory Failure, cont.
Pts. require O2 by nasal cannula or by
mechanical ventilator.
Weaning from vent:
MNT: varies
Body comp. fluctuation –