Respiratory Physiology

Front 1

need to remember following anatomy for double lumen placement:
lenght of right mainstem bronchus and it's anatomy

Back 1

The adult right main stem bronchus is ~2.5 cm long before it branches into lobar bronchi. In 10% of adults, the right upper lobe bronchus departs from the right main stem bronchus <2.5 cm below the carina. In 2 to 3% of adults, the right upper lobe bronchus opens into the trachea, above the carina.

Front 2

most sensitive clinical index of lung compliance.

Back 2

When lung compliance is reduced, larger changes in pleural pressure are needed to create the same tidal volume (VT). Patients with low lung compliance breathe with smaller VT and more rapidly,

Front 3

Carotid and aortic bodies are stimulated by

Back 3

Pao2 values less than 60 to 65 mm Hg. Thus, patients who depend on hypoxic ventilatory drive do not have Pao2 values >65 mm Hg.

Front 4

three causes of hyperventilation

Back 4

arterial hypoxemia, metabolic acidemia, and central etiologies (e.g., intracranial hypertension, hepatic cirrhosis, anxiety, pharmacologic agents).

Front 5

the ratio of alveolar ventilation to dead space ventilation during spontaneous ventilation?
and during positive pressure ventilation?

Back 5

2:1
1:1

Front 6

The most common reason for an acute increase in dead space ventilation

Back 6

decrease in cardiac ouput

Front 7

Smoking patients should be advised to stop smoking at least how long before surgery?

Back 7

2 months

Front 8

The highest risk for PPC is associated with

Back 8

nonlaparoscopic upper abdominal operations, followed by lower abdominal and intrathoracic operations.

Front 9

ventilatory muscles

Back 9

diaphragm, intercostal muscles, abdominal muscles, cervical strap muscles, sternocleidomastoid muscles, and the large back and intervertebral muscles of the shoulder girdle.

Front 10

With normal lungs, both breathing and coughing can be performed solely by ?

Back 10

the diaphragm

Front 11

At FRC the intrapleural space the pressure is?

Back 11

subambient pressure (-2 to -3 mm Hg

Front 12

how long is the trachea?

Back 12

10-12 cm

Front 13

how many cartillages in trachea?

Back 13

20

Front 14

cricoid membrane is at which level?

Back 14

C6

Front 15

what are the angles of the right and left mainstem bronchi?

Back 15

right bronchus leaves the trachea at ~25 degrees from the vertical tracheal axis, whereas the angle of the left bronchus is ~45 degrees

Front 16

how long is the right mainstem?

Back 16

2.5 cm

Front 17

how long is the left mainstem?

Back 17

5 cm

Front 18

type 2 pneumocytes and their function?

Back 18

These polygonal cells have vast metabolic and enzymatic activity and manufacture surfactant. The enzymatic activity required to produce surfactant is only 50% of the total enzymatic activity present in type II alveolar cells.6 The remaining enzymatic activity modulates local electrolyte balance, as well as endothelial and lymphatic cell functions.

Front 19

what is the normal pulmonary shunt?

Back 19

Anatomic connections between the bronchial and pulmonary venous circulations create an absolute shunt of ~2 to 5% of the total cardiac output, and represents “normal” shunt.

Front 20

In the upright adult, the difference in intrapleural pressure from the top to the bottom of the lung is

Back 20

~7 cm H2O

Front 21

laplace's law

Back 21

The Laplace equation describes this phenomenon: P = 2T/R, where P is the pressure within the bubble (dyne · cm-2), T is the surface tension of the liquid (dyne · cm-1), and R is the radius of the bubble (in centimeters).

Front 22

what is alveolar transmural pressure gradient, or transpulmonary pressure

Back 22

the difference between intrapleural and alveolar pressure and is directly proportional to lung volume

Front 23

Four conditions that will change laminar flow to turbulent flow

Back 23

high gas flows, sharp angles within the tube, branching in the tube, and a decrease in the tube's diameter.

Front 24

Physiologic aging of the lung is associated with ?
what happens to FRC?

Back 24

dilation of the alveoli, enlargement of the airspaces, decrease in exchange surface area, and loss of supporting tissue.20 Changes in the aging lung and chest wall result in decreased lung recoil (elastance), creating an increased residual volume and FRC.

Front 25

where are the respiratory centers?

Back 25

Within the pontine and medullary reticular formations, there are several discrete respiratory centers that function as the control system

Front 26

what is the pacemaker of the respiratory system in the medulla?

Back 26

Dorsal respiratory group`

Front 27

waht is apneustic breathing.

Back 27

Isolating the DRG in this manner results in ataxic, gasping ventilation with frequent maximum inspiratory efforts: apneustic breathing

Front 28

the expiratory coordinating center is the ?
and what does it do?

Back 28

The ventral respiratory group (VRG), which is located in the ventral medullary reticular formation. This VRG transmission prohibits further use of the inspiratory muscles, thus allowing passive expiration to occur.

Front 29

breathing center in the pons?

Back 29

the apneustic center, process medullary information

Front 30

what do peripheral chemoreceptors respond to? and central?

Back 30

the peripheral chemoreceptors respond primarily to lack of oxygen, and the central nervous system (CNS) receptors respond primarily to changes in PCO2, pH, and acid-base disturbances.

Front 31

what is the PCO2 in the CSF vs. systemic circulation and why?

Back 31

, once carbon dioxide crosses into the CSF, H+ are created and trapped in the CSF, resulting in a CSF H+ concentration considerably greater than that found in the blood. Because carbon dioxide crosses the blood–brain barrier readily, the Paco2 values in the CSF, cerebral tissue, and jugular venous blood rise quickly and to the same degree as the Paco2, although the central values are ~10 mm Hg higher than those measured in arterial blood

Front 32

ventilatory response to high PaCO2?

Back 32

The ventilatory response to changes in Paco2 (increased VT, increased respiratory rate) is rapid and peaks within 1 to 2 minutes after an acute change in Paco2

Front 33

effect of cold CSF on respiration?

Back 33

depression of respiration

Front 34

zone 1
relationship between PA, Ppa, Ppv?

Back 34

PA > Ppa > Ppv
zone 1 receives ventilation in the absence of perfusion

Front 35

zone 2, blood flow relationship.

Back 35

Ppa > PA > Ppv
The pressure difference between pulmonary artery and alveolar pressure determines blood flow in zone 2. Pulmonary venous pressure has little influence. Well-matched ventilation and perfusion occur in zone 2, which contains the majority of alveoli.

Front 36

zone 3, blood flow relationships.

Back 36

Ppa > PpV > PA
and blood flow is primarily governed by the pulmonary arterial to venous pressure difference.

Front 37

which area of the lung is better ventilated?

Back 37

the dependent part, due to incrased transpleural pressure

Front 38

The ideal [V with dot above]A/[Q with dot above] ratio, what is it and where?

Back 38

ratio of 1 is believed to occur at approximately the level of the third rib. Above this level, ventilation occurs slightly in excess of perfusion, whereas below the third rib the [V with dot above]A/[Q with dot above] ratio becomes less than 1

Front 39

v/q value for absolute deadspace =

Back 39

∞

Front 40

v/q ratio for absolute shunt =

Back 40

0

Front 41

what is shunt?

Back 41

small amount of ventilation relative to blood flow

Front 42

what is dead space?

Back 42

low blood flow relative to ventilation

Front 43

what is the 1,2,3 rule for ventilation?

Back 43

1 mL/lb (lean body weight) becomes VD, 2 mL · lb-1 becomes Va, and 3 mL · lb-1 constitutes the VT.

Front 44

what is the physiologic deadspace?
how to calculate it?

Back 44

consists of anatomic and alveolar dead space. Anatomic dead space ventilation, approximately 2 mL/kg ideal body weight, accounts for the majority of physiologic dead space. It arises from ventilation of structures that do not exchange respiratory gases: the oronasopharynx to the terminal and respiratory bronchioles.

Front 45

VD to VA relationship in a mechanically ventilated patient?

Back 45

1:1, if it's 1000 ml, then 500 is going to VA and 500 to VD

Front 46

for mechanically ventilated patients hwo does doubling baseline minute ventilation affect paCO2?

Back 46

decreases Paco2 from 40 to 30 mm Hg, and quadrupling minute ventilation decreases Paco2 from 40 to 20

Front 47

should you treat shunt w/ O2?

Back 47

Because blood passing through areas of absolute shunt receives no oxygen, arterial hypoxemia resulting from absolute shunt is minimally reversed with supplemental oxygen.

Front 48

how is FRC measured?

Back 48

indirectly,
ex: nitrogen washout

Front 49

FVC is reduced in?

Back 49

chronic obstructive diseases even when the vital capacity appears near normal. FVC is nearly always decreased by restrictive diseases

Front 50

what is FEV?

Back 50

Because FEVT records a volume of gas expired over time, it is actually a measure of flow. By measuring expiratory flow at specific intervals, the severity of airway obstruction can be ascertained.

Front 51

normal FEV / FVC ratio?

Back 51

Normal subjects can expire at least three fourths of FVC within the first second of the forced expiratory maneuver. The FEV1, the most frequently employed value, is normally ≥75% of the FVC, or FEV1/FVC ≥ 0.75.

Front 52

how much FVC can a patient expire in 0.5 sec, 1 sec, 2 sec, and 3 secs

Back 52

Normally, an individual can expire 50 to 60% of FVC in 0.5 second, 75 to 85% in 1 second, 94% in 2 seconds, and 97% in 3 seconds.

Front 53

what is maximum midexpiratory flow rate?

Back 53

The length of time required for a subject to expire the middle half of the FVC is divided into 50% of the FVC.

Front 54

maximum midexpiratory flow rate, why is it important?

Back 54

when decreased, there is obstructive disease of medium-sized airways. This value is typically normal in restrictive diseases. This test is fairly sensitive in the early stages of obstructive airway disease. it may be abnormal before any other signs of obstructive disease show up

Front 55

what is Maximum voluntary ventilation (MVV)?

Back 55

is the largest volume of gas that can be breathed in 1 minute by voluntary effort.

Front 56

what does MVV measure?

Back 56

MVV measures the endurance of the ventilatory muscles and indirectly reflects lung–thorax compliance and airway resistance. Healthy, young adults average ~170 L/min

Front 57

factors that influcence DLCO?

Back 57

thick membrane
Hemoglobin concentration: decreased hemoglobin concentration decreases the DLCO.
Alveolar Pco2: an increased PACO2 raises DLCO.
Body position: the supine position increases DLCO.
Pulmonary capillary blood volume.

Front 58

Screening spirometry tells you about?

Back 58

vital capacity (VC), FVC, and FEV1. From these values, two basic types of pulmonary dysfunction can be identified and quantitated: obstructive defects and restrictive defects. The primary criterion for airflow obstruction is decreased FEV1/FCV ratio.

Front 59

restrictive pattern on spirometry?

Back 59

A restrictive defect is a proportional decrease in all lung volumes; thus, VC, FVC, and FEV1 all are reduced, but FEV1/FVC remains normal. and TLC is low