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Flashcards in Respiratory 4 Deck (63)
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1
Q

Hemoglobin normally carries oxygen and carbon dioxide- what happens during carbon monoxide poisoning?

A

carbon monoxide binds tightly to hemoglobin and kicks off oxygen and carbon dioxide

2
Q

describe the characteristics of carbon monoxide

A

colorless, odorless, tasteless, non irritant gas

3
Q

what is the affinity for co to Hb compared to oxygen

A

250x more attracted to hemoglobin than oxygen

4
Q

CO+Hb=

A

HbCO-carboxyhemoglobin

5
Q

can HbCO carry 02?

A

no, functional anemia/anemic hypoxemia

6
Q

what if there is only a small concentration in the air of CO

A

CO can kill even in small concentrations

7
Q

what happens when carbon monoxide binds to one Hb site?

A

it increases the oxygen affinity of the remaining HB sites which causes the hemoglobin molecule to retain oxygen that would otherwise be delivered to the tissue.

8
Q

during carbon monoxide poisoning which way does the HbO curve shift

A

to the left- due to the 3 sites have an increase in oxygen affinity and retaining oxygen

LEFT-LOVE OF OXYGEN

9
Q

what is the result of the increase affinity between hemoglobin and oxygen during CO poisoning.

A

Blood oxygen content is increased! because oxygen remains on the hemoglobin- none is delivered to the tissues- HYPOXIC TISSUE INJURY

10
Q

what color do people turn with CO poisoning

A

Hb turns a bright red color- cadavers acquire an unnatural reddish hue

11
Q

Can a pulse Ox be reliable during CO Poisoning

A

NO! Pulse ox is misleading: it can’t differentiate between oxyHb and CarboxyHb

12
Q

Treatment of CO poisoning

A

100% 02 (will bump CO from Hb)

13
Q

S/S of CO poisoning

A

headache, vertigo, dyspnea, confusion, dilated pupil, convulsion and coma

14
Q

CO2 is produced in tissues and carried to the lungs. Name the 3 forms

A

HCO3 (90%0
carbaminohemoglobin (HbCO2)-small amount
Dissolved CO2-(is this in the plasma)?? small amount

15
Q

what is the formula for dissolved CO2 in the blood

A

PaCO2 x 0.067=xx/100ml blood

16
Q

explain the steps of co2 as HCO3

A

CO2 is produced in the tissues and diffuses into RBC

CO2+H20 (Carbonic anhydrase) form h2co3

h2co3 dissociates into h and hco3

hco3 leaves the RBC in exchange for Cl- and transported to lungs in the plasma

H is buffered inside RBC’s by deoxyHb

17
Q

explain how the lungs offload c02

A

HCO3 enters the RBC and Cl leaves

HCO3 bind with h= h2co3

then H20 and CO2

co2 leaves the lung and transport to the alveoli and gets breathed out

18
Q

Haldane effect

A

In lungs, oxygenation of Hb promotes dissociation of CO2 from Hb (Haldane effect); therefore, CO2 is released from RBCs

19
Q

Bohr effect

A

In peripheral tissue, increase H+ shift curve to right, unloading O2

20
Q

Central control of breathing name the structure in the brain

A

medullary respiratory center: located in reticular formation

Apneustic center

Pneumtaxic center

Cerebral cortex

21
Q

Dorsal Respiratory Group

A

(PACEMAKER)
Inspiratory Control
Receive Inputs via vagus and glossopharyngeal nerve
output to diaphragm via phrenic nerve and external intercostal nerves

22
Q

ventral respiratory group

A

Expiratory control
efferent via internal intercostal nerve
work only during exercise, when expiration becomes an active process

23
Q

glossopharyngeal nerve

A

carries signals from carotid bodies and vagus from arch of aorta and lung stretch receptors.

24
Q

Apneustic center

A

Located in lower pons

Stimulates inspiration, producing deep and prolonged inspiratory gasp (apneusis)

25
Q

Pneumtaxic cener

A

Located in upper pons
Inhibits respiration, and therefore inspiratory volume and respiratory rate.
Adjust rate and depth of respiration

26
Q

Cerebral cortex

A

Voluntary breathing; hypoventilation or hyperventilation

27
Q

Central Chemoreceptors are located where?

A

medulla

28
Q

what are these chemoreceptors respond to what?

A

CO2, H+, 02

29
Q

Central chemoreceptors are sensitive to??

A

PH of CSF

30
Q

if central chemoreceptors sense a decrease in PH what happens?

A

produces hyperventilation

31
Q

what does and does not cross the BBB

A

CO2-crosses the BBB

H+ does not cross the BBB

32
Q

In CSF: CO2 + H20=

A

H2CO3= -H + HCO3

H acts directly on central chemoreceptors

33
Q

increase pco2 and H do what to breathing

A

stimulate breathing

34
Q

decrease pc02 and H do what do breathing

A

Inhibit breathing

35
Q

what is the role of hyperventilation or hypoventilation

A

it returns the arterial PCO2 towards normal

36
Q

Central Control of Breathing. Name the two structures

A

Brain stem and cerebral cortex

37
Q

the brain stem coordinates what sensory information and sends signals to respiratory muscles

A
PC02
Lung stretch
irritants 
muscle spindles
tendons and joints
38
Q

where are peripheral chemoreceptors found?

A

in the carotid and aortic bodies

39
Q

what stimulates the peripheral chemoreceptors

A

decrease p02
increase pc02
decrease PH (increase H)

40
Q

the peripheral chemoreceptors are stimulated to increase the breathing rate in metabolic acidosis breathing rate is increased Why is that?

A

because arterial H is increased and PH is decreased

41
Q

name the last point that peripheral chemoreceptors are responsible for?

A

responsible to hypoxic drive to respiration

42
Q

Name the 6 other type of receptors for breathing control

A

stretch receptors on bronchial walls

irritant receptors stimulated by dust pollen

J (juxtacapillary) receptors

Joint and muscle receptors

Brain Edema

Anesthesia

43
Q

Stretch receptors on bronchial walls

A
  • Afferent via vagus nerve
  • When these receptors are stimulated by distension of the lungs, they produce a reflex decrease in breathing frequency (Hering-Breuer Reflex)
44
Q

Irritant receptors are stimulated by?

A

dust, pollen

45
Q

J (juxtacapillary) receptors

A

-Engorgement of pul. capillaries in LVH, stimulates J receptors, which then cause rapid, shallow breathing dyspnea

46
Q

Right-to-left shunts

A

Normally occur to a small extent because 2% of the cardiac output bypasses the lungs
abnormalities

47
Q

what congenital anomaly creates a right to left shunt?

to what % of CO is seen with congenital abnormalities

A

Are seen in tetralogy of Fallot

May be as great as 50% of cardiac output in certain congenital

48
Q

explain what is seen of PO2 in a right to left shunt

A

Always result in decrease arterial PO2 because of the admixture of venous blood with arterial blood

49
Q

how to we determine the magnitude of a right to left shunt?

A

The magnitude of the right-to-left shunt can be estimated by having the patient breathe 100% O2 and measuring the degree of dilution of oxygenated arterial blood by non-oxygenated shunted (venous) blood

50
Q

Left-to-right shunts

A

Are more common than right-to-left shunts because pressures are higher on the left side of the heart

51
Q

Left to right shunts are usually caused by what?

A

Are usually caused by congenital abnormalities( e.g. PDA, VSD, ASD) or traumatic injury

52
Q

in left to right shunt what happens to 02?

A

Do not result in a decrease in arterial PO2. Instead PO2 will be elevated on the right side of the heart because there has been admixture of arterial blood with venous blood

53
Q

Supplemental O2

A

For patient with PO2 ≤ 55mmHg
Hypoxic drive suppression
Oxygen toxicity
Parenchymal damage

54
Q

Mechanical Ventilation: indication

A

Apnea, inadequate ventilation
Severe hypoxemia despite O2 supplementation
Airway protection – in coma

55
Q

Cheyne-Stokes Respiration

A

Hypersensitivity of resp center to CO2
Period of waxing and waning of tidal volumes separated by periods of apnea
Drug overdose, CHF, hypoxia

56
Q

Pickwickian Syndrome

A

Obesity-hypoventilation syndrome

The association of sleep apnea with extreme obesity is referred to as Pickwickian syndrome

57
Q

Pickwickian Syndrome

Clinical signs

A
Partial airway obstruction causes snoring
Hypoxia-- decrease PO2
Cyanosis 
Rarely hypercapnia 
Polycythemia 
Poor sleep at night
Daytime sleepiness
58
Q

Pickwickian Syndrome

treatment

A

Oropharyngeal appliances
Positive pressure nasal mask
Surgery

59
Q

MAC=

A

Minimum Alveolar Concentration:

60
Q

tell me about mac

A

its the concentration of anesthetic gas needed to eliminate movements among 50% of patients challenged by standardized skin incision

MAC is small for potent anesthetics such as halothane and large for less potent gas such as N20

61
Q

Respiratory Responses to Exercise

A
O2 consumption
CO2 production
Ventilation rate
Arterial PO2 and PCO2
Arterial pH
Venous PCO2
Pulmonary blood flow
V/Q ratio
62
Q

Cardiovascular Responses to Exercise

A

B. flow to skeletal m.

H.R. SV, CO

63
Q

Adaptation to High Altitude

A
Alveolar PO2		         
Arterial PO2	                  
Ventilation rate		         
Arterial pH		                  
Hb Concentration                  
2,3-DPG		                  
Hb-O2 Curve	                  
Pul. Vascular 
resistance