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59 Cards in this Set
- Front
- Back
need to remember following anatomy for double lumen placement:
lenght of right mainstem bronchus and it's anatomy |
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.
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most sensitive clinical index of lung compliance.
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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,
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Carotid and aortic bodies are stimulated by
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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.
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three causes of hyperventilation
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arterial hypoxemia, metabolic acidemia, and central etiologies (e.g., intracranial hypertension, hepatic cirrhosis, anxiety, pharmacologic agents).
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the ratio of alveolar ventilation to dead space ventilation during spontaneous ventilation?
and during positive pressure ventilation? |
2:1
1:1 |
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The most common reason for an acute increase in dead space ventilation
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decrease in cardiac ouput
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Smoking patients should be advised to stop smoking at least how long before surgery?
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2 months
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The highest risk for PPC is associated with
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nonlaparoscopic upper abdominal operations, followed by lower abdominal and intrathoracic operations.
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ventilatory muscles
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diaphragm, intercostal muscles, abdominal muscles, cervical strap muscles, sternocleidomastoid muscles, and the large back and intervertebral muscles of the shoulder girdle.
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With normal lungs, both breathing and coughing can be performed solely by ?
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the diaphragm
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At FRC the intrapleural space the pressure is?
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subambient pressure (-2 to -3 mm Hg
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how long is the trachea?
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10-12 cm
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how many cartillages in trachea?
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20
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cricoid membrane is at which level?
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C6
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what are the angles of the right and left mainstem bronchi?
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right bronchus leaves the trachea at ~25 degrees from the vertical tracheal axis, whereas the angle of the left bronchus is ~45 degrees
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how long is the right mainstem?
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2.5 cm
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how long is the left mainstem?
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5 cm
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type 2 pneumocytes and their function?
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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.
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what is the normal pulmonary shunt?
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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.
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In the upright adult, the difference in intrapleural pressure from the top to the bottom of the lung is
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~7 cm H2O
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laplace's law
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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).
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what is alveolar transmural pressure gradient, or transpulmonary pressure
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the difference between intrapleural and alveolar pressure and is directly proportional to lung volume
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Four conditions that will change laminar flow to turbulent flow
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high gas flows, sharp angles within the tube, branching in the tube, and a decrease in the tube's diameter.
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Physiologic aging of the lung is associated with ?
what happens to FRC? |
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.
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where are the respiratory centers?
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Within the pontine and medullary reticular formations, there are several discrete respiratory centers that function as the control system
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what is the pacemaker of the respiratory system in the medulla?
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Dorsal respiratory group`
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waht is apneustic breathing.
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Isolating the DRG in this manner results in ataxic, gasping ventilation with frequent maximum inspiratory efforts: apneustic breathing
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the expiratory coordinating center is the ?
and what does it do? |
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.
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breathing center in the pons?
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the apneustic center, process medullary information
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what do peripheral chemoreceptors respond to? and central?
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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.
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what is the PCO2 in the CSF vs. systemic circulation and why?
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, 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
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ventilatory response to high PaCO2?
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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
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effect of cold CSF on respiration?
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depression of respiration
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zone 1
relationship between PA, Ppa, Ppv? |
PA > Ppa > Ppv
zone 1 receives ventilation in the absence of perfusion |
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zone 2, blood flow relationship.
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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. |
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zone 3, blood flow relationships.
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Ppa > PpV > PA
and blood flow is primarily governed by the pulmonary arterial to venous pressure difference. |
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which area of the lung is better ventilated?
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the dependent part, due to incrased transpleural pressure
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The ideal [V with dot above]A/[Q with dot above] ratio, what is it and where?
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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
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v/q value for absolute deadspace =
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∞
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v/q ratio for absolute shunt =
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0
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what is shunt?
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small amount of ventilation relative to blood flow
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what is dead space?
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low blood flow relative to ventilation
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what is the 1,2,3 rule for ventilation?
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1 mL/lb (lean body weight) becomes VD, 2 mL · lb-1 becomes Va, and 3 mL · lb-1 constitutes the VT.
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what is the physiologic deadspace?
how to calculate it? |
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.
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VD to VA relationship in a mechanically ventilated patient?
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1:1, if it's 1000 ml, then 500 is going to VA and 500 to VD
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for mechanically ventilated patients hwo does doubling baseline minute ventilation affect paCO2?
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decreases Paco2 from 40 to 30 mm Hg, and quadrupling minute ventilation decreases Paco2 from 40 to 20
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should you treat shunt w/ O2?
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Because blood passing through areas of absolute shunt receives no oxygen, arterial hypoxemia resulting from absolute shunt is minimally reversed with supplemental oxygen.
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how is FRC measured?
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indirectly,
ex: nitrogen washout |
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FVC is reduced in?
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chronic obstructive diseases even when the vital capacity appears near normal. FVC is nearly always decreased by restrictive diseases
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what is FEV?
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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.
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normal FEV / FVC ratio?
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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.
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how much FVC can a patient expire in 0.5 sec, 1 sec, 2 sec, and 3 secs
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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.
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what is maximum midexpiratory flow rate?
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The length of time required for a subject to expire the middle half of the FVC is divided into 50% of the FVC.
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maximum midexpiratory flow rate, why is it important?
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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
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what is Maximum voluntary ventilation (MVV)?
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is the largest volume of gas that can be breathed in 1 minute by voluntary effort.
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what does MVV measure?
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MVV measures the endurance of the ventilatory muscles and indirectly reflects lung–thorax compliance and airway resistance. Healthy, young adults average ~170 L/min
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factors that influcence DLCO?
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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. |
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Screening spirometry tells you about?
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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.
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restrictive pattern on spirometry?
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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
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