Anestesiologia UIS Hipoxemia perioperatoria

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Anestesiologia UIS

Hipoxemia perioperatoriaAnestesiologia UIS

Hipoxemia perioperatoriaDr. Raúl Vásquez

LOGOHistoria

La anestesia general se asocia con hipoxemia

LOGOFisiologia

Oxigenación EntregaO2 (DO2)

Consumo O2 (VO2)

• Metabolismo celular aerobico

Oxygenation and mechanisms of hypoxemia

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• Disminucion de la entrega de oxigeno de la atmosfera a la sangre arterial (oxigenación

insuficiente)

Definicion

Hipoxemia

• Disminucion de la entrega de oxigeno de la sangre arterial a

los tejidosHipoxia

Monitoring Respiratory Function

LOGOIncidencia

The incidence of hypoxemia during

surgery: evidence from two Institutions

Duration of Hypoxemic Episodes at Hospitals A & B. The incidence and maximum duration of intraoperative hypoxemic episodes. Episodes are grouped by maximum duration per patient for both hypoxemic (SpO2\90) and severely hypoxemic episodes (SpO2 B 85). The percentage of patients experiencing two consecutive minutes or longer of hypoxemia and severe hypoxemia was 6.8% and 3.5%, respectively

Can J Anesth/J Can Anesth (2010) 57:888–897

Hipoxemia perioperatoria

LOGOIncidencia

Can J Anesth/J Can Anesth (2010) 57:888–897


• 1 : 15 Hipoxemia por dos minutos• 1 : 64 Hipoxemia ≥ 5 minutos

• ˃3 millones pacientes hipoxemia ≥ 5 min

234 Millones Cx Año

LOGOEfectos Deletereos

• Altera cicatrización, integridad anatomosis y resistencia a infección

Arch Surg 1997; 132: 991-6. Arch Surg 1997; 132: 997-1005. N Engl J Med 2000; 342: 161-7

• Translocacion bacteriana GI – SepsisArch Surg 1996; 131: 57-62

• Disfunción cognitiva – delirioAm J Med 1981; 79:1247-54. Br J Anaesth 1994; 72: 286-90

• ↓↑GC, precipita arritmias, hipertensión arterial, Taquicardia, isquemia

Anesthesiology 1999; 91: 1246-52. Br Heart J 1993; 69: 3-5


LOGOMedidas Oxigenacion

• Examen físico– Cianosis franca 5 g/dl deoxihemoglobina

SaO2 67%

• GASA gold standard PaO2

• SaO2 “Quinto signo vital”– Proyecto global pulso oximetria OMS

• 100000 pulso oximetros


Pulse oximetry

LOGOOximetría de Pulso



LOGOPulso Oximetria

Depicted here is the oxyhemoglobin dissociation curve for normal adult hemoglobin (Hemoglobin A, solid line). Note that hemoglobin is 50 percent saturated with oxygen at a partial pressure of 27 mm Hg (ie, the P50 is 27 mm Hg) and is 100 percent saturated at a pO2 of approximately 100 mm Hg. Depicted here are curves that are "left-shifted" (blue line, representing increased oxygen affinity) and "right-shifted" (red line, decreased oxygen affinity). The effect of right- or left-shifting of the curve is most pronounced at low oxygen partial pressures. In the examples shown, the right-shifted curve means that hemoglobin can deliver approximately 70 percent of its attached oxygen at a pO2 of 27 mm Hg. In contrast, the left-shifted hemoglobin can deliver only about 35 percent of its attached oxygen at this pO2. A high proportion of fetal hemoglobin, which has high oxygen affinity, shifts this curve to the left in newborns.


Pulse oximetry

LOGOOximetria de Pulso

• Aumenta deteccion hipoxemia 20 veces• Dx temprano

– Intubación endobronquial– Hipoventilacion

• Pacientes monitorizado– 50% menos eventos isquemia miocárdica


Global Pulse Oximetry Project


• La monitorización perioperatoria con oximetría de pulso no resulta en mejores resultados, efectividad o eficacia.

• No reduce transferencia a UCI ni mortalidad y es incierto si existe beneficio real en Cx Cardiotoracica


Oximetría de pulso para la monitorización perioperatoria 2008


Mala ColocacionArtefacto Movimiento

Mala ColocacionArtefacto Movimiento

LuzAmbiental

LuzAmbiental

RadiaciónElectromagnetica

RadiaciónElectromagnetica

Fuentes comunes de artefacto

Pulse oximetry

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Hg

Anormales

Hipoperfusion

Hipotermia

Congestion

Venosa

Pigmentacion

Piel

Colorantes

Vitales

Esmalte

Anemia

Oximetría de Pulso

Errores relacionadosCon el Paciente

Pulse oximetry


• Tension arterial de O2 PaO2• Gradiente Alveolo-arterial O2• Radio PaO2/FiO2• Radio Oxigeno Alveolo-arterial• Indice de Oxigenacion• Fraccion Shunt



LOGOGradiente A-a

• Diferencia cantidad oxigeno en el alveolo PAO2 y cantidad de O2 disuelto en el plasma PaO2

• Varia con la edad– Gradiente A-a= (edad/4) + 4– 10 mmHg jovenes, 30mmHg 70 años



PAO2=(FiO2x[Patm-PH2O])-(PaCO2/R)

LOGOGradiente A-a

http://www.mdcalc.com/a-a-o2-gradient

http://www.mdcalc.com/a-a-o2-gradient

LOGOGradiente A-a


Hipoxemia

Causa

↓PIO2HipoventilacionMismach V/Q

Shunt D-ITtno Difusion

P(A-a)O2

NormalNormal

↑↑↑↑↑↑

Rta O2 100%

↑↑↑↑↑↑

No Mejora↑↑

PaCO2

Normal↑↑

NormalNormalNormal

Anesthesiology Clinics of North America - Volume 19, Issue 4 (December 2001)

LOGOGradiente A-a

• ↑FiO2 = ↑PAO2 y ↑PaO2

– La PAO2 ↑desproporcionadamente• ˂40 años FiO2 100% 8 a 82 mmHg• ˃40 años FiO2 100% 3 a 120 mmHg



LOGOFraccion Shunt D-I

• Gold standar de oxigenacion eficiente en los pulmones

• Shunt 50%= Falla respiratoria severa• Shunt 5%= Normal


Qs/Qt=(CcO2-CaO2)/(CcO2-CvO2)

CaO2=(1.34xHgbxHgbO2)+(0.003xPO2)


• 33 pctes con SDRA• Relacionaron shunt con radio O2 A/a,

PaO2/FiO2, gradiente A-a, IR, radio O2 a/A

• PaO2/FiO2 variable mas facil que predice con exactitud el grado de shunt en falla respiratoria


Oxygen derived variables in acute respiratory failure Crit Care Med. 1983 Aug;11(8):646-9

LOGORadio PaO2/FiO2

• Normal= 300 a 500 mmHg• ˂300 mmHg= Intercambio gaseoso

anormal• ˂200 mmHg= Hipoxemia severa se

correlaciona con Shunt ˃20%



LOGOCausas

↓Oxígeno inspirado

Hipoventilación

Alteración V/Q

Difusión limitada

.

Hipoxemica

Anemica

Circulatoria

Afinidad

Histotoxica

Hipoxemia Hipoxia

Monitoring Respiratory FunctionOxygenation and mechanisms of hypoxemia

Shunt Derecha-Izquierda

LOGOBajo PIO2

PERIOPERATIVE HYPOXIA

The Clinical Spectrum and Current Oxygen Monitoring Methodology

Barometric pressure (PB) and inspired oxygen (O2 ) tension or partial pressure in millimeters of mercury (mm Hg) related to altitude in thousands of feet and in meters. The PB at Denver, the Mile High City, is 640 mm Hg, and the PIO2 there is 134 mm Hg in dry air. Point 1 is at 5500 meters in the Peruvian Andes, the highest point of continuous human habitation, where the PB is 380 mm Hg, and the PIO2 in dry air is 80 mm Hg. The air is not dry at the alveolus. By the time the inhaled air reaches the alveolus, it is saturated with H2 O vapor (47 mm Hg at 37°C irrespective of the elevation or PB). At 5500 meters, H2 O vapor decreases the PIO2 from 80 to 70 mm Hg). Supplemental oxygen is usually required at point 2, although Mount Everest has been climbed without O2 . Point 3 represents the highest ascent with O2 but without superatmospheric pressure.



LOGOEcuación 1

• ↓PIO2 = ↓PAO2

PIO2 = FiO2 X (PB – PH20)


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Morgan, Edward: Anestesiologia clinica – Seccion I capitulo 3 y 4. 2007

Flujometros

• Guarda Hipóxica– Mecánica, neumática o electrónica– Garantiza FiO2 25%

• Flujo Metabolico O2: Peso¾ x 10

LOGOHipoventilación

• Ventilación minuto inadecuada (↑CO2)– FR x VC

Normal



CO2 CO2O2

O2

O2

O2

CO2 CO2

CO2

CO2

O2O2

O2

Hipoventilado

CO2

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PAO2=0.21x(760-47)-PaCO2/0.8

100=0.21x(760-47)-40/0.8 Ventilacion Normal PaCO2 40

50=0.21x(760-47)-80/0.8Hipoventilacion PaCO2 80

FiO2 21%

114=0.3x(760-47)-80/0.8Hipoventilacion PaCO2 80

FiO2 30%

• Corrige al ↑FiO2

• Gradiente A-a normal

Hipoventilación

Oxygenation and mechanisms of hypoxemiaAnesthesiology Clinics of North America - Volume 19, Issue 4 (December 2001)

Hipoventilación Pura

Depresion SNC Obesidad Alt ConducciónNeural

DebilidadMuscular

↓ Elasticidad Pared Torácica

Sobredosis Lesión

estructural Lesíón

isquemica

Sx Pickwickian

ELA Guillant Barre

Lx Cervicalalta

Paralisis NFrenico

. BAminoglicosido

MiasteniaGravis

Paralisis diafragmatica

IdxPolimiositis

Distrofiamuscular

Hipotiroidismo

Torax InestableCifoescoliosis

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• El balance V/Q es complejo– Volumen ventilatorio– Presion alveolar– Compliance pulmon y caja toracica– Resistencia de la via aerea– Gravedad– Posicion del paciente– Flujo sanguineo pulmonar– Modo ventilatorio

Imbalance V/Q


V sin Q Espacio Muerto

Q sin V Shunt

LOGOImbalance V/Q

• Enfermedad pulmonar obstructiva• Enfermedad vascular pulmonar• Enfermedad intersticial


LOGOFalla Respiratoria

HipoxemicaAguda

HipoventilacionAlveolar

PerioperatoriaAguda

HipoperfusionShock

Tipo IV

Tipo I

Tipo II

Tipo III Atelectasias, dolor incisionalanalgesia inadecuada, alteracion tos,

uso de tabaco 6 semanas precx sobrehidratación

Critical Care. Just the Facts 2007

LOGOAtelectasias

In normal lungs (A), the alveolar inflation and vascular prfusion are associated with low stress and are not injurious. Two separate barriers form the alveolar– capillary barrier, the microvascular endothelium, and the alveolar epithelium. e

Pulmonary Atelectasis

A Pathogenic Perioperative Entity

Anesthesiology, V 102, No 4, Apr 2005

In contrast, with atelectasis (B), alveolar inflation and deflation may be heterogeneous, and the resulting airway stress causes epithelial injury. Because the blood vessels are compressed, perfusion may be traumatic because of flowinduced disruption of the microvascular endothelium. Both epithelial and endothelial injury may initiate or ropagate lung injury. This figure depicts the advanced stage of lung injury caused by atelectasis. The initial injury is simple collapse of alveoli. However, with time, this leads to an inflammatory reaction. As the derecruited lungs cause epithelial injury and loss of epithelial integrity, both type I and type II alveolar cells are damaged. Injury to type II cells disrupts normal epithelial fluid transport, impairing the removal of edema fluid from the alveolar space. In ddition to collapse, derecruited lungs also become fluid filled. Neutrophils adhere to the injured capillary endothelium and migrate through the interstitium into the alveolar airspace.In the airspace, alveolar macrophages secrete cytokines, interleukin (IL)-1, -6, -8, and -10, and tumor necrosis factor (TNF)-, which act locally to stimulate chemotaxis and activate neutrophils. IL-1 can also stimulate the production of extracellular matrix by fibroblasts. Neutrophils can release oxidants, proteases, leukotrienes, and other proinflammatory molecules, such as platelet-activating factor (PAF). MIF macrophage inhibitory factor.

LOGOShunt (Qs/Qt)

• Derecha a izquierda– Anatomico

• Intracardiaco, MAV, Venas bronquiales

– Transpulmonar• Area Q no V

– Atelectasias– Neumonia– Edema pulmonar– Aspiracion


LOGOAtelectasias


ReabsorcionGas

CompresionPulmonar

AlteracionSurfactante

Tres sets de mecanismos causan o contribuyena la formacion de atelectasias

Etiologia y Patogenesis

LOGOCompresion Pulmonar

Hagberg: Benumof's Airway Management, 2nd ed

LOGOReabsorcion Gas


• Oclusion completa de la via aerea• ↑FiO2

• Va/Q Bajo

LOGOAtelectasias


LOGOAtelectasias

Hipoxemia

Alt Compliance Pulmonar

↑RVP

Lesion pulmonar

VC bajo, hiperoxia (microatelectasias)Reversada por hiperinflacion

Reduccion volumen pulmonar, macroatelectasias.Empeora oxigenacion sistemica

Vasoconstriccion hipoxica pulmonar ↓ Tension Oxigeno alveolar y venoso mixto

Atelectasias + VC ↑Prevenida con PEEP


Complicaciones

LOGOAtelectasias


Pulmon sano Hiperinsuflación • 3 sucesivas

-20 cm H2O x 10 seg-30 cm H2O x 15 seg-40 cm H2O x 15 seg

• Nunn et al-40 cm H2O x 40 seg

• TusmanReclutamiento alveolar

Depende del Pulmon!

Prevencion - Reversion

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Schematic representation of the “Alveolar Recruitment Strategy”: PEEP is incremented in 3 steps of 5 cmH2O each. The vertical rectangles represent tidal breathing with a tidal volume of 7-9 mg/kg BW at a respiratory rate of 8 bpm. At a PEEP of 15 cmH2O tidal volumes are increased until a maximum tidal volume of 18 ml/kg or a peak airway pressure of 40 cmH2O is reached. These settings are applied for 10 breaths. Thereafter, tidal volumes are reduced to the previous values. Finally, PEEP is set to a level of 5 cmH2O in two steps.

Reclutamiento Alveolar

Tusman G et al. Alveolar Recruitment Strategy normalizes arterial oxygenation

Pulmón Sano

LOGOAtelectasias


Pulmon sano Hiperinflación pasiva

• 3 sucesivas-20 cm H2O x 10 seg-30 cm H2O x 15 seg-40 cm H2O x 15 seg

• Nunn et al-40 cm H2O x 40 seg

• TusmanReclutamiento alveolar

Pulmon Lesionado

-Evitar ↑VC, presiones pico elevadas, atelectrauma-Usar PEEP

Depende del Pulmon!

Prevencion - Reversion

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SobredistensionBaro - Volotrauma - LAD

VENTANA SEGURA

AtelectasiasEstres por deslizamiento, alteracion por surfactante

Ventilacion Mecanica

Barboza, Miguel Fisiologia de la ventilacion Unipulmonar

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Gracias!Gracias!Por la Paciencia

LOGOIncidencia

Management of the Difficult AirwayA Closed Claims

Analysis

* Percent of row resulting in death or brain damage (death/BD). † Bonferroni

P 0.04, 1993–1999 vs. 1985–1992.

Anesthesiology, V 103, No 1, Jul 2005

Anestesiologia UIS Hipoxemia perioperatoria

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