reason for patients being ventilated and
the length of time that they have been
receiving ventilation.
The main reason for initiating ventilation is
that a patient is unable to breathe
adequately without receiving artificial
assistance. The period of ventilation is
kept to a minimum, as the intervention itself
can result in the patient experiencing a
number of problems.
Decisions to remove patients from
mechanical ventilation are taken when it has
been decided that their condition has
improved and they appear able to breathe
adequately without artificial assistance.
These are difficult decisions to make, and
one of the main adverse consequences of
removing patients from mechanical
ventilation is that they are unable to breathe
independently. This may be due to the
recurrence of the original medical condition
or as a consequence of their medical
treatment (Adam and Osborne, 2005).
Patients who have been receiving
ventilation for a long period will have
undergone changes in their respiratory
physiology that will be reversed when this
therapy is discontinued. While they are on
the ventilator the respiratory muscles have
to do very little work. Once artificial
ventilation is stopped these muscles have to
take over the full work of breathing. This
extra effort can often make the patients feel
weak and exhausted (Mårtensson and
Fridlund, 2002).
When on a ventilator the patient is
receiving oxygen in a carefully controlled
amount that has been humidified and can
be easily adjusted depending on the
patient’s condition.
Once ventilatory support has been
completely discontinued the patient
normally receives supplementary oxygen
through a mask covering the nose/mouth or
tracheotomy. It is less easy to regulate the
exact amount of oxygen the patient is
receiving and it can be difficult to maintain
an adequate level of humidification. For
these reasons one of the effects of
discontinuing artificial ventilation can be a
reduction in blood oxygen levels.