1. FISIOLOGIA DEL INTERCAMBIO
GASEOSO ALVEOLO-CAPILAR
Dr. José Llagunes
Consorcio
Hospital General
Valencia.
02/14/13 1
2. FISIOLOGIA DEL INTERCAMBIO
GASEOSO ALVEOLO-CAPILAR
RESPIRACIÓN:
Externa: Aporte de O2 del medio ambiente
a los pulmones (alveolos) Eliminación del
CO2 de los alveolos al exterior.
Interna: Captación del O2 alveolar y su
transporte al interior celular. Transporte del
CO2 celular a los alveolos.
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3. FISIOLOGIA DEL INTERCAMBIO
GASEOSO ALVEOLO-CAPILAR
Externa:
Aporte de O2
del medio
ambiente a
los pulmones
(alveolos)
Eliminación
del CO2 de
los alveolos
al exterior
4. FISIOLOGIA DEL INTERCAMBIO
GASEOSO ALVEOLO-CAPILAR
Interna:
Captación del O2
alveolar y su
transporte al
interior celular.
Transporte del
CO2 celular a
los alveolos.
11. FISIOLOGIA DEL INTERCAMBIO
GASEOSO ALVEOLO-CAPILAR
RESPIRACIÓN EXTERNA:
CONVECCIÓN:Proceso tiene lugar a
nivel de las grandes vías aereas.
DIFUSIÓN: Captación gases a nivel
alveolar y su transporte sanguineo.
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15. FISIOLOGIA DEL INTERCAMBIO
GASEOSO ALVEOLO-CAPILAR
Difusión de los gases respiratorios
– Proceso pasivo. No energia
– Desplaz. dentro vía aérea, paso
membrana alveolo-capilar y paso
atraves de los poros de Kohn
(interalveolar)
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16. FISIOLOGIA DEL INTERCAMBIO
GASEOSO ALVEOLO-CAPILAR
Ley de la difusión gaseosa:
– Ley de Graham:
Dgas= 1/ Γpmg
DCO2/DO2 =0,15/0,17=1,17
O2 difunde en fase gaseosa 1,17
más que el carbonico
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18. FISIOLOGIA DEL INTERCAMBIO
GASEOSO ALVEOLO-CAPILAR
Ley de la difusión en liquido
Ley de Henry: difusión es proporcional a la solulbilidad de
cada uno de ellos en liq. Dgas= S x P.gas
1/(mwCO2)1/2 SCO
2
20
DCÒ2/D`O2 = x =
1/(mwO2)1/2 SO
2
1
Solub.CO2=0.592
Solub.O2=0.024
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20. FISIOLOGIA DEL INTERCAMBIO
GASEOSO ALVEOLO-CAPILAR
Ley de la difusión transmembrana:
– Ley de Fick:
V`gas= S(p1-p2)D/E
S=superficie membrana
P: presiones a ambos lados
D: difusión del gas membrana
E: espesor de la misma
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21. FISIOLOGIA DEL INTERCAMBIO
GASEOSO ALVEOLO-CAPILAR
Limitaciones:
– Coef. Difusión
– La superficie
– Espesor membrana
– Gradiente de presiones parciales
(velocidad de difusión)
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23. FISIOLOGIA DEL INTERCAMBIO
GASEOSO ALVEOLO-CAPILAR
1. CAPTACIÓN O2 EN SANGRE
Presión alveolar de oxigeno
1. PA= PiO2 - PaCO2/ R
2. PiO2= FiO2 (Pb-PH2O)
Gradiente alveolo-arterial de O2
P(A-a)O2= [FiO2 (Pb-PH2O)] - PaCO2/ R) - PaO2
Combinación con la Hb
24. FISIOLOGIA DEL INTERCAMBIO
GASEOSO ALVEOLO-CAPILAR
Tranferencia a nivel Hb:
– Presión parcial del gas en sangre capilar
– pH y Tª de la sangre capilar
– El gasto cardiaco (tiempo de paso)
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26. FISIOLOGIA DEL INTERCAMBIO
GASEOSO ALVEOLO-CAPILAR
LUEGO:
– procesos activos acoplados:
PULMON
CORAZON
– resultado final va a ser:
Oxigeno: DO2 y VO2
Carbonico: CO2 y É CO2
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27. FISIOLOGIA DEL INTERCAMBIO
GASEOSO ALVEOLO-CAPILAR
Circulación bronquial
Circulación pulmonar
Sistema circulatorio de baja
presion
En ausencia de shunt
intracardiaco el flujo
pumonar es igual al gasto
cardiaco
31. FISIOLOGIA DEL INTERCAMBIO
GASEOSO ALVEOLO-CAPILAR
Grafica de la presión alveolar de CO2 y de la presión
alveolar de O2 en función de la zona del pulmón
34. ALT. VENTILACIÓN/PERFUSIÓN:
aumento del espacio muerto
Dos componentes espacio
muerto fisiologico:
anatomico y alveolar
Espacio muerto definición:
areas del pulmon bien
ventiladas pero mal
perfundidas.
35. ALT. VENTILACIÓN/PERFUSIÓN:
aumento del espacio muerto
– Alteración intercambio gaseoso:
– Aumento del espacio muerto
pCO2a-EtCO2
Ecuación Bohr:
Vd/Vt=(PaCO2-EtCO2)/PACO2
0,2-0,4 Con v. Mecanica y peep puede llegar a 0,55
38. ALT. VENTILACIÓN/PERFUSIÓN:
aumento shunt intrapulmonar
Anatomico: circulación bronquial, venas
Tebesio etc. 2-5% del GC
Dos componentes: anatomico y alveolar= shunt
fisiologico
Shunt pulmonar:areas mal ventiladas pero bien
perfundidas
Respuesta a la administración de O2
Shunt absoluto
Shunt realativo
39. ALT. VENTILACIÓN/PERFUSIÓN:
aumento shunt intrapulmonar
Medición:
Qs/Qp= (CcO2-CaO2)/ (CcO2-CvO2)
Formula abreviada por Civetta et al.
1- SaO2
Qs/Qt= x 100
1-SvO2
Utilizar: SvcO2 mediante cateter venoso central
40. FISIOLOGIA DEL INTERCAMBIO
GASEOSO ALVEOLO-CAPILAR
EFECTOS DE LA ANESTESIA
1.- Cambios a nivel toracico y
abdominal
2.- Conllevan cambios
de las capacidades pulmonares
FCR and CC
Volumenes de sangre
3.- Alt. en el intercambio gaseoso de
oxigeno
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48. Uso de las presiones en vía
aérea
P pico aumentada con Pm sin cambios :
•Obstrucción del TET
•Vía aérea obstruida por secreciones
•Broncoespasmo agudo
49. Uso de las presiones en vía
aérea
P meseta y P pico aumentadas:
•Neumotorax
•Atelectasia Lobar
•EAP
•Neumonia
•ARDS
•COPD con taquipnea y auto-PEEP
•Aumento de la presión intraabdominal
•Respiración asisncronica
50. Uso de los flujos vía aerea
En combinación con volumenes:
•TIEMPO INSPIRATORIO/ESPIRATORIO ADECUADOS
51. Uso de LA ESPIROMETRIA
Nos permite guardar
bucle de refencia
Diferenciar entre
proceso obstructivo y
restrictivo
Mejor metodo para
valorar los cambios
efectuados en el
respirador o la terapia
instaurada
64. AJUSTES DE LA
VENTILACIÓN MECÁNICA
Regladel 7 : al 100% de O2 representan
700 mmHg. Luego: 1% de O2 = 7 mmHg
Restar el % de la FiO2
Ajuste
pCO2:
PCO2/PCO2’=Vt/Vt’
Notas del editor
Instead of the usual list, follow these rules: There is a tendency to delay intubation as long as possible in the hopes that it will be unnecessary. Elective intubation carries fewer dangers than emergent intubation. So, if the patient’s condition is severe enough that intubation is considered, then proceed without delay Remember you will never be faulted for establishing the control of airways ETT and ventilators do not create the need for mechanical ventilation: cardiopulmonary and neuromuscular disease do
Instead of the usual list, follow these rules: There is a tendency to delay intubation as long as possible in the hopes that it will be unnecessary. Elective intubation carries fewer dangers than emergent intubation. So, if the patient’s condition is severe enough that intubation is considered, then proceed without delay Remember you will never be faulted for establishing the control of airways ETT and ventilators do not create the need for mechanical ventilation: cardiopulmonary and neuromuscular disease do
Instead of the usual list, follow these rules: There is a tendency to delay intubation as long as possible in the hopes that it will be unnecessary. Elective intubation carries fewer dangers than emergent intubation. So, if the patient’s condition is severe enough that intubation is considered, then proceed without delay Remember you will never be faulted for establishing the control of airways ETT and ventilators do not create the need for mechanical ventilation: cardiopulmonary and neuromuscular disease do
Instead of the usual list, follow these rules: There is a tendency to delay intubation as long as possible in the hopes that it will be unnecessary. Elective intubation carries fewer dangers than emergent intubation. So, if the patient’s condition is severe enough that intubation is considered, then proceed without delay Remember you will never be faulted for establishing the control of airways ETT and ventilators do not create the need for mechanical ventilation: cardiopulmonary and neuromuscular disease do
Instead of the usual list, follow these rules: There is a tendency to delay intubation as long as possible in the hopes that it will be unnecessary. Elective intubation carries fewer dangers than emergent intubation. So, if the patient’s condition is severe enough that intubation is considered, then proceed without delay Remember you will never be faulted for establishing the control of airways ETT and ventilators do not create the need for mechanical ventilation: cardiopulmonary and neuromuscular disease do
Instead of the usual list, follow these rules: There is a tendency to delay intubation as long as possible in the hopes that it will be unnecessary. Elective intubation carries fewer dangers than emergent intubation. So, if the patient’s condition is severe enough that intubation is considered, then proceed without delay Remember you will never be faulted for establishing the control of airways ETT and ventilators do not create the need for mechanical ventilation: cardiopulmonary and neuromuscular disease do
Instead of the usual list, follow these rules: There is a tendency to delay intubation as long as possible in the hopes that it will be unnecessary. Elective intubation carries fewer dangers than emergent intubation. So, if the patient’s condition is severe enough that intubation is considered, then proceed without delay Remember you will never be faulted for establishing the control of airways ETT and ventilators do not create the need for mechanical ventilation: cardiopulmonary and neuromuscular disease do
Instead of the usual list, follow these rules: There is a tendency to delay intubation as long as possible in the hopes that it will be unnecessary. Elective intubation carries fewer dangers than emergent intubation. So, if the patient’s condition is severe enough that intubation is considered, then proceed without delay Remember you will never be faulted for establishing the control of airways ETT and ventilators do not create the need for mechanical ventilation: cardiopulmonary and neuromuscular disease do
Instead of the usual list, follow these rules: There is a tendency to delay intubation as long as possible in the hopes that it will be unnecessary. Elective intubation carries fewer dangers than emergent intubation. So, if the patient’s condition is severe enough that intubation is considered, then proceed without delay Remember you will never be faulted for establishing the control of airways ETT and ventilators do not create the need for mechanical ventilation: cardiopulmonary and neuromuscular disease do
Instead of the usual list, follow these rules: There is a tendency to delay intubation as long as possible in the hopes that it will be unnecessary. Elective intubation carries fewer dangers than emergent intubation. So, if the patient’s condition is severe enough that intubation is considered, then proceed without delay Remember you will never be faulted for establishing the control of airways ETT and ventilators do not create the need for mechanical ventilation: cardiopulmonary and neuromuscular disease do
Instead of the usual list, follow these rules: There is a tendency to delay intubation as long as possible in the hopes that it will be unnecessary. Elective intubation carries fewer dangers than emergent intubation. So, if the patient’s condition is severe enough that intubation is considered, then proceed without delay Remember you will never be faulted for establishing the control of airways ETT and ventilators do not create the need for mechanical ventilation: cardiopulmonary and neuromuscular disease do
Instead of the usual list, follow these rules: There is a tendency to delay intubation as long as possible in the hopes that it will be unnecessary. Elective intubation carries fewer dangers than emergent intubation. So, if the patient’s condition is severe enough that intubation is considered, then proceed without delay Remember you will never be faulted for establishing the control of airways ETT and ventilators do not create the need for mechanical ventilation: cardiopulmonary and neuromuscular disease do
Instead of the usual list, follow these rules: There is a tendency to delay intubation as long as possible in the hopes that it will be unnecessary. Elective intubation carries fewer dangers than emergent intubation. So, if the patient’s condition is severe enough that intubation is considered, then proceed without delay Remember you will never be faulted for establishing the control of airways ETT and ventilators do not create the need for mechanical ventilation: cardiopulmonary and neuromuscular disease do