Respiratory Monitoring Flashcards

Question

... is the O2 saturation of blood at the proximal pulmonary artery. Normal values range between... . Values close to ... are associated with tissue hypoxia, anaerobic metabolism, and lactate production

Answer 1

Mixed venous oxygen saturation (SvO2) 65% and 80% 40%

Answer 2

DO2 = Q x CaO2 VO2 = Q x (CaO2 - CvO2) x 10 ERO2 = VO2/DO2

Answer 3

the brain and upper extremities 2% to 5% less higher O2 content of splanchnic and renal venous blood the upper body reverse

Answer 4

Increase of VO2: * Pain * Shivering * Agitation * Hyperthermia Reduction of DO2 * Heart failure * Hypovolemia * Hypoxia * Anemia * COHb

Answer 5

Reduction of VO2 * Sedation * Anesthesia * Analgesia * Warming * Respiratory support Increase of DO2 * Inotropic agent * IV fluid * Transfusion * O2 therapy

Answer 6

a wedged pulmonary artery tip, mitral regurgitation, or left- to- right shunts

Answer 7

There is no gold standard for cerebral oximetry. Furthermore, each device has its own set of “normal” values.

Answer 8

20% to 25% 50%

Answer 9

F Patients undergoing shoulder surgery in the beach chair position have a lower baseline rSO2 and a larger number of episodes of cerebral desaturation, although the clinical implications of these findings are unclear

Answer 10

can be used to estimate the ratio of physiologic dead space (VD) to tidal volume (VT) Vd/Vt = (PaCO2 - PeCO2) / PaCO2, PeCO2 is the mixed expired CO2 partial pressure,

Answer 11

water and nitrous oxide

Answer 12

- Phase 0 (or IV) is the inspiratory segment - Phase I corresponds to the exhalation of dead space gas from the central conducting airways or any equipment distal to the sampling site, which ideally should have no detectable CO2 (i.e., partial pressure of CO2, PCO2 ∼ 0); - Phase II corresponds to a sharp rise in PCO2 to a plateau, indicating the sampling of transitional gas between the airways and alveoli. - Phase III, the plateau region of the capnogram, corresponds to the PCO2 in the alveolar compartment *** Phase IV (or IV') denotes the upstroke observed at the end of phase III in some patients. This upstroke probably results from the closure of lung units with relatively low PCO2 and allows for regions of higher CO2 to contribute a greater proportion of the exhaled gas to be sampled

Answer 13

a heterogeneous distribution of ventilation–perfusion (V/Q) or alveolar CO2 partial pressure (PACO2) throughout the lung

Answer 14

Faulty inspiratory valve: Results is a slower downslope, which extends into the inhalation phase (phase 0) as CO2 in the inspiratory limb is rebreathed

Answer 15

↑CO2 PRODUCTION AND DELIVERY TO THE LUNGS Increased metabolic rate Fever Sepsis Seizures Malignant hyperthermia Thyrotoxicosis Increased cardiac output (e.g., during CPR) Bicarbonate administration ↓ALVEOLAR VENTILATION Hypoventilation Respiratory center depression Partial muscular paralysis Neuromuscular disease High spinal anesthesia COPD EQUIPMENT MALFUNCTION Rebreathing Exhausted CO2 absorber Leak in ventilator circuit Faulty inspiratory/expiratory valve

Answer 16

↓CO2 PRODUCTION AND DELIVERY TO THE LUNGS Hypothermia Pulmonary hypoperfusion Cardiac arrest Pulmonary embolism Hemorrhage Hypotension ↑ALVEOLAR VENTILATION Hyperventilation EQUIPMENT MALFUNCTION Ventilator disconnect Esophageal intubation Complete airway obstruction Poor sampling Leak around endotracheal tube cuff

Answer 17

Increased ventilation–perfusion heterogeneity, particularly with high V/Q regions Pulmonary hypoperfusion Pulmonary embolism Cardiac arrest Positive pressure ventilation (especially with PEEP) High-rate low-tidal-volume ventilation

Answer 18

The inspiratory phase

Answer 19

- It allows for estimation of the relative contributionsof anatomic and alveolar components of physiologic dead space - It is more sensitive than the time capnogram in detecting subtle changes in dead space thatare caused by alterations in PEEP, pulmonary blood flow, or ventilation heterogeneity - May provide useful information on cardiac output and intravascular volume responsiveness. - The numeric integral of PCO2 as a function of volume allows for determination of the total mass of CO2 exhaled during a breath and provides for the estimation of VCO2

Answer 20

Phase I anatomic dead space Phase II transitional Phase III alveolar gas

Answer 21

Area X corresponds to the total volume of CO2 exhaled over a tidal breath. This value can be used to compute the CO2 production (V˙ CO2), and the mixed expired CO2 fraction or partial pressure to beused in the Bohr equation based on the division of the exhaled CO2 volume by the exhaled tidal volume. Area Y represents wasted ventilation due to alveolar dead space, while area Z corresponds to wasted ventilation due to anatomic deadspace (VDaw). Thus areas Y + Z represent the total physiologic dead space

Answer 22

(1) hypoventilation, (2) V/Q mismatching, (3) right-to-left shunt, (4) diffusion limitation, and (5) diffusion–perfusion mismatch

Answer 23

<1% drainage of the bronchial and Thebesian veins into the arterial side of the circulation

Answer 24

The three compartments represent: (1) lung regions receiving both ventilation and perfusion, (2) a shunt compartment (V/Q = 0), and (3) a dead space compartment with ventilation but no perfusion (V/Q = infinity)

Answer 25

QS/QT = (Cc'O2 - CaO2) / Cc'O2 - CvO2) QS is the shunted blood flow, QT is total cardiac output Cc′O2 is the endcapillary O2 content

Answer 26

QS/QT = (1 - SaO2) / (1 - SvO2) where SaO2 is arterial saturation, and SvO2 is mixed venous saturation

Answer 27

OI = 100 x (FiO2 x Pao) / PaO2 where Pao denotes the mean airway pressure OSI = 100 x (FiO2 x Pao) / SpO2

Answer 28

alpha-stat and pH-stat

Answer 29

During alpha-stat management, blood gas measurements obtained after the analyzer warms the sample to 37°C are used for acid–base and gas exchange management. Potential benefits of alpha-stat management include the preservation of cerebral autoregulation and the maintenance of protein function. From GPT: - Ignores temperature when measuring blood gases. Keeps the patient1s CO2 and pH at "normal" 37 °C values, no matter the actual body temperature; - Target: pH 7,4; PaCo2 40 mmHg - Doesn't add or subtract CO2 during coolin or warming. - It preserves intracellular charge balance (hence "alpha" from de degree of dissociation of histidine residues in proteins). It's about maintaining enzyme function and autoregulation. - COns: Brain blood flow drops with cooling, so you might undershoot cerebral perfusion in kids or ischemic-prone brains.

Answer 30

During pH-stat management, measurements are corrected to the patient’s temperature before they are used for acid–base and gas exchange management. Because patients are hypothermic, the PaO2 and PaCO2 at the patient’s temperature are lower and the pH higher than those measured in the analyzer at 37°C. CO2 is usually added to the oxygenator to maintain the temperature-corrected PaCO2 and pH at normothermic values. The theoretical benefits of pH-stat management are increased cerebral vasodilation leading to more homogeneous cerebral cooling From GPT: - It adds CO2 to maintain pH of 7,4 at the new temperature; - Pros: maximizes uniform brain cooling, good for pediatric braons that don't autoregulate as weel; - COns: can impair autoregulation, increase ICP and risk microemboli.

Answer 31

Studies have compared the two strategies with respect to outcomes with varying results. In general, clinical studies support the use of pH-stat management in pediatric cardiac surgical procedures during HCPB or DHCA. In adult patients, the use of alpha-stat management is supported for HCPB. For procedures involving DHCA in adults, the use of pH-stat management has been suggested to increase the rate and uniformity of cooling and alpha-stat management during rewarming

Answer 32

Delays in sample analysis and the presence of air in the sampling syringe. A delay in sample analysis by 20 minutes at room temperature or at 4°C can lead to a decline in PaO2. The decline is attributed to the metabolic activity of leukocytes and is not observed in samples placed on ice. The presence of an air bubble in the syringe can lead to a change in the measured PaO2 toward the PO2 of the bubble and decline in PaCO2

Answer 33

consolidation, pulmonary edema, pneumothorax, atelectasis, interstitial disease, pneumonectomy or surgical resection, lung overdistention, and mainstem intubation

Answer 34

abdominal distention, abdominal compartment syndrome, chest wall edema, thoracic deformity, muscle tone, and extensive thoracic or abdominal scar (e.g., from burns)

Answer 35

energy required to inflate or deflate the lungs, or chest wall, or both, by a specified volume the product of the applied distending pressure and resulting volume change (W = PV) *** However, when pressure and volume vary as functions of time (as during the course of a spontaneous or controlled breath), work may be expressed as the cumulative product (W = ∫PdV)

Answer 36

inspiration respiratory rate frequency frequency energetically optimum breathing frequency

Answer 37

developing ventilator- induced lung injury * However, whether mechanical power may be predictive of ventilator- induced lung injury, or any meaningful clinical outcomes in ventilated patients with ARDS, is still a matter of contention

Answer 38

Ideally, airway pressure should be the pressure measured in the trachea or at the airway opening, exclusive of any distortions from airway devices or breathing circuits. However, for practical reasons, this “airway” pressure is not the actual pressure at the airway opening or within the trachea, but is the pressure transduced at the anesthesia machine or ventilator and reflects the resistive and compliant properties of the breathing circuit and face mask or ETT, as well as the mechanical properties of the respiratory system. Although many ventilators now use computer algorithms to provide some compensation for flow and pressure losses in the breathing circuit, such approaches often rely on idealized, linear models that do not truly reflect the complex processes of turbulent air flow, polytropic gas compression, or viscoelastic tubing walls.

Answer 39

airway pressure and atmospheric pressure obesity, abdominal insufflation, or steep Trendelenburg position

Answer 40

the distending pressure across the lungs alone airway opening pressure pleural space esophageal balloon catheter esophagus intrapleural

Answer 41

transrespiratory whole respiratory system 26 to 30 cmH2O

Answer 42

occluding the airway at end exhalation, and observing a rise in airway pressure during the occlusion maneuver until a plateau is visible (<4 seconds)

Answer 43

Changes in thoracic electrical impedance (impedance pneumography) of the chest wall. The method is based on the changes in electrical conductivity of the chest to an electrical current as air moves in and out of the lungs during breathing and blood volume changes in the sameperiod. This is because air is a poor electrical conductor and blood is a good electrical conductor. A low electrical current at high frequency is applied in two chest electrodes, corresponding changes in voltage of the chest are measured, and the impedance is continuously calculated from these. The technique is implemented inseveral commercial systems using routine electrocardiographic leads and is also used in home monitoring of neonatal apnea

Answer 44

(1) Hyperventilation: Compensated respiratory distress (e.g., from sepsis, pulmonary embolus, orcongestive heart failure): patients presentinitially with stable SpO2 and decreasing PaCO2 as metabolicacidosis develops with associated compensatory hyperventilation. High respiratory rate is typical of this pattern. Ultimately, a slow desaturation is followed by an abrupt fall inoxygenation as the ventilatory response to worsening acidosis fails. (2) Progressive unidirectional hypoventilation or CO2 narcosis: frequently due to opioid or other sedative overdose, it is characterized by a rise in PaCO2 (and PETCO2) initially because of decreased minute ventilation, often while SpO2 remains above 90%. (3) Sentinel rapid airflow/O2 saturation reduction with precipitous SpO2 fall observedin patients with obstructive sleep apnea, who are dependenton the arousal state to maintain oxygenation. Sleep results in precipitous hypoxemia during apnea with potential sudden arrest.

Answer 45

high 10–12 lower 1-5 5 to 7

Answer 46

A discrete laserlike vertical hyperechoic reverberation artifact that arises from the pleural line (previously described as “comet tails”), extends to the bottom of the screen without fading, moves synchronously with lung sliding, and erases A-lines.

Respiratory Monitoring Flashcards

(73 cards)