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www.einstein.br. www.slacip.com.br. Gracias por la invitación. Modalidades básicas de ventilación mecánica. We need to have two primary goals in mind: (1) to ease the work of breathing in the critically ill neonate
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Trinidad , Buenos Aires , Argentina: 7 a 9 de junio www.einstein.br www.slacip.com.br Gracias por la invitación
We need to have two primary goals in mind: (1) to ease the work of breathing in the critically ill neonate (2) to reduce the incidence of neonatal lung injury, or bronchopulmonary dysplasia (BPD) Eichenwald & Stark, NEJM 2008 Modalidades básicas de ventilación mecánica.
What is Mode? Volume or Pressure ?? Phase Variables Cycling Pressure Controlled Ventilation Patient Triggered Ventilation Modalidades básicas de ventilación mecánica
What is Mode? Volume or Pressure ?? Phase Variables Cycling Pressure Controlled Ventilation Patient Triggered Ventilation Modalidades básicas de ventilación mecánica
Mode of ventilation is the method or way ,in which a breath is delivered by altering or changing the available variables. A Mode is nothing but how a ventilator performs the work of respiratory muscles What is Mode?
1. Type of breath 2. Control variables 3. Phase variables 4. Conditional variables Components of a Mode
1a. Mandatory breath 1b. Assist breath 1c. Support breath 1d. Spontaneous breath 1. Type of breath
2a. Pressure control 2b. Volume control 2c. Dual control mode 2. Control variables
Pressure = Flow x Resistance + Volume/compliance Flow Resistance = ΔpressureΔflow Pressure Volume Compliance = Δ volumeΔ pressure
What is Mode? Volume or Pressure ?? Phase Variables Cycling Pressure Controlled Ventilation Patient Triggered Ventilation Modalidades básicas de ventilación mecánica
Volume Preset Pressure preset • Volume Preset ventilators: deliver the same tidal volume of gas each breath, regardless of the inflating pressure that is needed. • Pressure-preset ventilators,: in contrast, are designed to deliver a volume of gas with each breath until a preset limiting pressure designated by the physician is reached.
Volume Preset Pressure preset • Volume Preset ventilators : deliver the same tidal volume of gas each breath, regardless of the inflating pressure that is needed. • Pressure-preset ventilators,: The remainder of volume in the unit is then released into the atmosphere. As a result, the tidal volume that is delivered to the patient by pressure-preset ventilators with each breath may be variable, but the peak pressure delivered to the airway remains constant
Pressure control simply means the breaths are pressure constant and volume variable. Pressure control
Volume control simply means the breaths are volume constant and pressure variable. Volume control
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Dual control mode are newer modes which are capable of switching from one to another , e.g., pressure regulated colume control (PRVC), Auto mode, Adaptative pressure ventilation (APV) Dual control Mode
Termination of inspiration is now recognized to be an important component of ventilator control, because prolongation and plateau formation during inspiration , especially with pressure limited modes, may lead to air trapping air leak, and chronic lung injury. Be Aware
The Volume Guarantee Ventilation was introduced to more tightly regulate the volume delivery to the lung ( Babylog 8000) In VGV, the operator chooses a target tidal volume and selects a pressure limit up to which the inspiratory pressure may be adjusted. Volume Guarantee Ventilation (VGV)
The microprocessor of the unit then compares exhaled tidal volume of the prior breath to the desired target and readjust the inspiratory pressure up or down to deliver the targeted tidal volume. Volume Guarantee Ventilation (VGV)
Exhaled tidal volume is used in this mode for the regulation of the inspiratory pressure because it more closely approximates the tidal volume in the neonate who has a leak around an uncuffed endotracheal tube. Volume Guarantee Ventilation (VGV)
The newer modalities of ventilatory support are byproducts of the modern computer era and have been made possible by the use of microprocessors that permit very small beneficial modifications to pressure, flow and volume throughout the ventilatory cycle. VoluTrauma
The primary rationale behind these novel approaches is that the volume delivered to the lung, or volutrauma, may be of greater importance in the lung injury than the pressure injury or barotrauma. McCallion et al : Volume targeted versus pressure limited ventilation in NB , Cochrane Database Syst Rev VoluTrauma
Volutrauma Barotrauma • Hillman et al: Briel, large tidal volume ventilation initiates lung injury and a systemic response in fetal sheep AJRCCM 15; 176: 575-581, 2007 • Moylan et al: The relationship of Bronchopulmonary dysplasia to the occurrence alveolar rupture during positive pressure ventilation. Crit Care Med 6: 140-142, 1978 Volutrauma vs barotrauma
What is Mode? Volume or Pressure ?? Phase Variables Cycling Pressure Controlled Ventilation Patient Triggered Ventilation Modalidades básicas de ventilación mecánica
a. Trigger variable b. Limiting variable c. Cycling variable d. Baseline variable Phase variables
: • TRIGGER: starts the inspiration • Limit variable means that does not allowed to rise above a preset value during inspiratory time • Cycling Variable: end inspiration • Baseline variable How the ventilator starts, sustains and ends inspiration Phase Variables 2 3 1 4
Trigger variable – What starts inspiration a) Machine trigger or time trigger when the ventilator starts a breath according to a set frequency b) Patient trigger: pressure or flow. When the ventilator senses a drop in baseline pressure or flow when caused by the patient’s inspiratory effort a. Trigger variable
Patient effort Pressure • Baseline -2 cm H2O Trigger Pressure Triggering
Fluxo 1.0 LPM Pressão Subida da Pressão 25 msec Fluxo Tempo de Resposta do Sistema DISPARO • FLUXO X PRESSÃO
Tidal Volume (liters) 1.0 Ventilator Disconnected Compare to BASE FLOW 5 LpmFLOW SEN 1 Lpm 0.9 0.8 Ideal ContinuousFlow 0.7 0.6 0.5 0.4 0.3 0.2 Flow Triggered Spontaneous Breath 0.1 0 -20 -15 -10 -5 0 5 10 15 20 Simulated Carina Pressure (cmH20)
Volume (l) 1.0 Ventilator Disconnected Compare to CPAP ModeSen = 0.5 cmH2 0 0.9 0.8 0.7 Ideal ContinuousFlow 0.6 0.5 0.4 0.3 0.2 Pressure Triggered Spontaneous Breath 0.1 0 -20 -15 -10 -5 0 5 10 15 20 Simulated Carina Pressure (cmH20)
Circuit pressure(flow triggered) Circuit pressure(pressure triggered) I1 I2 Pressure trigger point Flow trigger point Onset of effort Patient inspiring from base flow Trigger fluxo x pressão Pressure-Supported Breaths Pressure cmH20 Trigger Interval I1 = Flow triggered I2 = Pressure triggered Net flow Lpm Time
Delivered Flow Returned Flow Base Flow Flow Sensitivity Time Airway Pressure PatientEffort Baseline Inspiratory Flow Time LegendFlow TriggeringPressure Triggering Returned Flow DeliveredFlow Inspiratory Flow
Returned flow Delivered flow No patient effort Flow Triggering
All inspiratory efforts recognized Pressure Time Flow Triggering
Less flow returned Delivered flow Flow Triggering
Limit variable means available variable is not allowed to rise above a preset value during the inspiratory time: Pressure limit Volume limit Limiting variable
The variable that is measured and used to end inspiration is called cycle variable: Time cycled – cycling is due to set inspiratory time Volume cycled Flow cycled Cycling variable
Cycling variable – what ends inspiration Pico de fluxo + PINSP 25% do pico de fluxo Fluxo Pressão PEEP - Tempo 20 10 Pressão Volume 0 Tempo Tempo
What is Mode? Volume or Pressure ?? Phase Variables Cycling Pressure Controlled Ventilation Patient Triggered Ventilation Modalidades básicas de ventilación mecánica
CMV / Assist mandatory ventilation are full support modes. Full support modes are required in acutely ill patients who require guaranteed and often high minute ventilation . Controlled mandatory ventilation
These modes perform most or all of the work of respiratory muscles, necessary to maintain adequate minute ventilation. Because of full support , these modes also reduce the oxygen and energy consumed by the respiratory muscles. Controlled mandatory ventilation
These patients can neither trigger breath nor inspire air through the ventilatory circuit. The patient’s respiratory effort should be suppressed by sedative, intentional hyperventilation or muscle relaxants. Precautions with CMV
1. To provide maximum ventilatory support to a patient with marginal cardiorespiratory reserve 2. Controlling minute ventilation for reducing in cerebral blood volume and intracranial pressure are urgent priorities 3. Reducing oxygen consumption in patients with respiratory fatigue with poor cardiac output Indications of CMV
4. Ventilatory total control facilitates the therapeutic application of nonphysiologic breathing patterns ( Permissive hypercapnia) 5. To reduce agitation in the patient fighting the ventilator 6. Helps to heal the injured chest wall 7. Status Epilepticus Indications of CMV