Assisted spontaneous breathing

This article or the following section is not adequately provided with supporting documents ( e.g. individual evidence ). Information without sufficient evidence could be removed soon. Please help Wikipedia by researching the information and including good evidence.

The assisted spontaneous breathing , English Assisted Spontaneous Breathing (ASB), and ASV, English Assisted Spontaneous ventilation , and inspiration assistance , is a form of respiration in the intensive care , wherein the pressure level of the ventilator after the start of the patient raised started spontaneous inspiration (inhalation) and thus self-breathing is supported.

It uses this form of respiration as assisted ventilation, so the patient is breathing. He controls the respiratory rate after his own feelings , and the ventilator supports a breathable by a preset pressure . The ventilated patient does not have to apply this pressure that the device applies. It is sufficient einzu a little breath , and the unit completes the initiated breath.

The ventilation is triggered by what is known as a trigger . At the beginning of inhalation, the patient himself generates a flow of breathing gas which the ventilator recognizes (so-called flow trigger). The flow is recorded by the device. If the breathing gas flow generated by the patient exceeds the pre-set threshold, i.e. the set trigger level, the breathing device presses breathing air into the ventilated person for a certain time at the pre-set higher pressure, thus making it easier to breathe. Older devices work with a so-called pressure trigger, i. H. the patient must fall below the pressure level of the exhalation phase by a preset value. This type of trigger is associated with greater exertion for the patient.

ASB can be easily combined with BIPAP and CPAP ventilation modes . Especially during weaning (training off from the ventilator), it offers well-adaptable breathing support for the patient and is therefore a helpful element to guide the patient back to spontaneous breathing, i.e. to breathing independently of the machine.

Necessary control parameters for monitoring

• Breathing rate (respiration)
• Minute volume and spontaneous minute volume (the two do not have to be identical , because with BIPAP ventilation it is possible that the respirator, i.e. the ventilator, performs breathing rates and the patient does not perform his own breathing)
• Tidal volume inspiratory (when breathing in) and expiratory (when breathing out), in the technical term we speak of tidal volume
• Blood gases and oxygen saturation
• Stress parameters such as blood pressure , pulse and sweating

It is therefore urgently indicated that a patient who needs breathing assistance is cared for in an intensive care unit in the hospital , as this is the only place where all parameters can be monitored. In addition, ventilators are only available in intensive care units that can support people in their breathing work. Of course, emergency doctors and ambulances are also equipped with a ventilation unit (which, however, usually only ventilates in a controlled manner), but ASB plays a subordinate role in the context of the initial care of patients.

In the further course, if the ventilation situation and general condition of the patient are stable, this can also be carried out at home if ventilation is likely to be necessary for a longer period of time (e.g. in the case of paraplegia or amyotrophic lateral sclerosis). This requires the permanent presence of a nursing service who specializes in home ventilation.

Setting parameters on the ventilator

• Trigger threshold, either a pressure trigger (is usually set between −0.5 and −1 mbar) or a flow trigger (usually a flow rate of around 3 l / min (1–5 l / min))
• ASB pressure, also called auxiliary pressure (starting with an ASB depending on the patient's condition of e.g. 22, which is reduced during weaning , less than 8 mbar is unusual)
• PEEP pressure (varies according to the needs of the patient; is set as low as possible; ventilation is often started with a PEEP of 5 mbar and then stopped later, the PEEP is rarely below, occasionally - depending on the clinical picture - also significantly above)

Adjustments are made by a doctor or an experienced nurse, the liability rests with the doctor. If the patient's situation changes (e.g. due to pulmonary exhaustion), the ventilation parameters must be adjusted.

Contraindications and limitations of the ASB

There is no contraindication to ASB. The necessary settings can be made for any form of ventilation that allows this. However, it depends on the patient's depth of sedation and compliance whether ASB works. As already described above, it is a question of pressure support which, in the event of spontaneous breathing, provides respiratory support via the auxiliary pressure. If the patient has no breathing activity of his own, he will not take advantage of the offer of auxiliary pressure.

Individual evidence

1. ↑ D. Weismann: Forms of ventilation. In: J. Kilian, H. Benzer, FW Ahnefeld (ed.): Basic principles of ventilation. Springer, Berlin a. a. 1991, ISBN 3-540-53078-9 , 2nd, unchanged edition, ibid. 1994, ISBN 3-540-57904-4 , pp. 201-211; here: pp. 203-209.

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !