What is a ventilator?
Mechanical ventilators are electromechanical devices that support or ventilatory support for patients who can not breathe on their own or who need assisted ventilation to maintain adequate ventilation to allow them to maintain optimal bloodoxygenation. Invasive mechanical ventilation (IMV) of based on the supply of oxygen-enriched air to the lungs causing a positive pressure in the lungs, unlike thespontaneous breathing that makes a negative pressure to get air into the lungs.
The key concept is the respiratory cycle:
Shot or start of inspiration
Maintenance of inspiration
Cycling, changes in the inspiratory phase the expiratory
Tidal volume or tidal volume (VC): The amount of air that sends the patient breathingwith each breath.
Minute volume, is obtained by multiplying the respiratory rate per minute and tidal volume of each breath.
VM pressure is the force per unit area required to move a tidal volume. It depends on two new concepts compliance and resistance of the system.
Peak pressure is the value in cm H2O obtained at the end of inspiration, related to the system resistance to airflow in the anatomical and artificial channels and the elasticity of the lung and rib cage.
Plateau pressure, plateau or static is the value at the end of inspiration by pausingand without inspiratory airflow. It relates to compliance toracopulmonar.
Mean alveolar pressure (Paw mean) is the average of all values of pressure relax thelungs and chest during a respiratory cycle until there inspiratory and expiratoryresistance or. Can be related to the volume of the chest means.
Positive end-expiratory pressure (PEEP): The pressure at the end of expiration must be zero, but in a therapeutically or derived from the clinical situation can becomepositive, allowing the reopening of alveolar recruitment of collapsed areas
At the initiation of mechanical ventilation must be established the followingparameters:
Respiratory rate (f).
Tidal volume (Vt) and minute (Vm).
Relationship inspiratory / expiratory (I: E).
Total ventilatory support techniques (SVT):
The ventilator does all the work to maintain effective alveolar ventilation.
Includes the following ways:
Controlled mechanical ventilation or IPPV.
Assist-control mechanical ventilation (AMV / c).
Mechanical ventilation with I: E ratio inverted (IRV).
Differential mechanical ventilation or pulmonary independent (SIL).
Partial ventilatory support techniques (SVP):
Both the patient and the ventilator work together to contribute to the effective alveolar ventilation.
Pressure assisted or support ASB.
Synchronized intermittent mandatory ventilation or SIMV.
Ventilation with two levels of pressure, BIPAP.
Continuous pressure on the airway, CPAP.
Mandatory minute volume, MMV
It assisted ventilation type that requires a patient's inspiratory effort, in which the ventilator cycles to detect such an inspiration inspiratory effort. Thus, the patient stillbreathing rate, and indirectly also the tidal volume. When the fan is detected (through the trigger or sensitivity) refers the patient inspiration flow of gases with a high initialpeak during inspiration to maintain a fixed pressure level which is usually between about 10 and 20 cmH2O. The patient should keep the stimuli of normal ventilation and should not be receiving sedatives or muscle relaxants.
This method reduces the fatigue caused by the work of breathing and improves the efficiency of the muscles of respiration. The fan takes in part the work of inspiration,although the patient remains in control of spontaneous breathing, so it has become abest mode for weaning from the ventilator.
They are designed to support through appropriate mechanical ventilation (MV) have tobe simple and manageable compact and lightweight to be handled by qualified personnel in a hospital (transfers) and outpatient (cardiopulmonary resuscitation).
Utility-hospital diagnostic testing (CT, MRI)
Utility Extraospitalaria: Transport Primary and secondary ground or air transportationmeans.
-FiO2: Normally 50% 0 100%.
-Minute volume or tidal volume: 8-12ml/kg.
-Respiratory rate: Between 10 and 20.
Noninvasive mechanical ventilation is a form of ventilatory support which can
keeping the airway intact, does not require endotracheal intubation or tracheostomy, thus avoiding the risk of pneumonia associated
reducing the needs of sedation of the patient. Ventilation ismore physiological, less aggressive in some situations allowing oral feeding.
Respirators noninvasive ventilation (compensated leak, easy to use and program,transport, allowing home use, allow a few ways, not all have oxygen incorporatedsome allow only monitoring). Models are cycled pressure (BiPAP Respironics) and volume (Breas, O'nyx).
IPAP. You can control the ventilation, the higher the IPAP, the higher tidal volume is generated during inspiration.
EPAP. Use this parameter to control the residual volume, controlling the functional capacity and oxygenation to maintain open airway and alveoli distended.
Ti: inspiratory time. To control the duration of the IPAP.
Ramp slope or inspiratory flow: This parameter can vary the speed and shape of the air entering the airways. The more slowly through the air in the airways, the longer the duration of ramp-time best the child will adapt to this mode of mechanical ventilation.The shorter, more abruptly enter the air and is easier for the patient try to fight thisfeeling so sudden and decoupling of the VM.
FiO2. Using this parameter can vary the percentage of O2 in the air.