Critical care units such as intensive care units (ICUs) and critical care units (CCUs) provide specialized intensive care for critically ill patients. There are many different types of ICUs depending on medical specialty, such as neonatal ICUs, cardiac ICUs, and surgical ICUs. ICUs are equipped with mechanical ventilators and extensive monitoring equipment to support vital organ functions. Mechanical ventilation is often required to assist patients who cannot breathe adequately on their own. There are various modes of mechanical ventilation to meet patients' different respiratory needs.

1. Critical care units

4. An Intensive Care Unit (ICU) or
Critical Care Unit (CCU
) is a specialised facility in a hospital that provides
intensive care medicine. Many hospitals also have designated
intensive care areas for certain specialities of medicine, as
dictated by the needs and available resources of each hospital.
The naming is not rigidly standardized.

5. Specialized types of ICUs include
 :
 Neonatal intensive care unit (NICU)
 Special Care Baby unit (SCBU)
 Pediatric Intensive Care Unit (PICU)
 Psychiatric Intensive Care Unit (PICU)
 Coronary Care Unit (CCU) for heart disease
 Medical Intensive Care Unit (MICU)
 Surgical Intensive Care Unit (SICU)
 Cardiac Surgery Intensive Care Unit (CSICU)
 Neuroscience Critical Care Unit (NCCU)
 Overnight Intensive Recovery (OIR)
 Neuro Intensive Care Unit (NICU)
 Burn Wounds Intensive Care Unit
 Trauma Intensive care Unit (TICU)
 Shock Trauma Intensive care Unit (STICU)

6. Equipment and systems
Common equipment in an ICU includes
mechanical ventilator; dialysis equipment for renal
problems; equipment for the constant monitoring of
bodily functions; a web of intravenous lines, feeding
tubes, nasogastric tubes, suction pumps, drains and
catheters; and a wide array of drugs to treat the main
condition(s), induce sedation, reduce pain, and prevent
secondary infections

7. Mechanical ventilation

8. Mechanical ventilation
is a method to mechanically assist or replace spontaneous
breathing when patients cannot do so on their own, and must
be done so after invasive intubation with an endotracheal or
tracheostomy tube through which air is directly delivered (in
contrast to noninvasive ventilation).

9. Common indications for mechanical
ventilation
 Apnea with respiratory arrest
 Acute lung injury
 Respiratory rate >30 breaths per minute
 Chronic obstructive pulmonary disease (COPD)
 Clinical deterioration
 Respiratory muscle fatigue
 Obtundation or coma
 Hypotension
 Tachypnea or bradypnea
 Blood gases showing persistent hypoxemia
 Acute partial pressure of carbon dioxide (PCO2) of >50 mm Hg with pH
<7.25
 Neuromuscular disease

10. A mechanical ventilator
is a machine that generates a controlled flow of gas into a
patient’s airways. Oxygen and air are received from
cylinders or wall outlets, the gas is pressure reduced and
blended according to the prescribed inspired oxygen tension
(FiO2), accumulated in a receptacle within the machine, and
delivered to the patient using one of many available modes of
ventilation.

12. ways to ventilate a patient?
There really is only two ways to ventilate a patient, using
(conventional) positive pressure or negative pressure. Some
of the earliest ventilators were negative pressure chambers
(iron lungs).

13. Mode or Breath Pattern
 CMV = Conventional controlled ventilation, without
allowances for spontaneous breathing. Many anesthesia
ventilators operate in this way.
 Assist-Control = Where assisted breaths are facsimiles of
controlled breaths.
 Intermittent Mandatory Ventilation = Which mixes
controlled breaths and spontaneous breaths. Breaths
may also be synchronized to prevent "stacking".
 Pressure Support = Where the patient has control over
all aspects of his/her breath except the pressure limit.)

14. Modes of ventilation
Assist Control (AC). In this mode the ventilator provides a
mechanical breath with either a preset tidal volume or peak
pressure every time the patient initiates a breath. Traditional
assist-control used only a preset tidal volume--when a preset
peak pressure is used this is also sometimes termed
Intermittent Positive Pressure Ventilation or IPPV

17. Synchronized Intermittent Mandatory
Ventilation (SIMV).
 In this mode the ventilator provides a preset mechanical breath
(pressure or volume limited) every specified number of seconds
(determined by dividing the respiratory rate into 60 - thus a
respiratory rate of 12 results in a 5 second cycle time). Within
that cycle time the ventilator waits for the patient to initiate a
breath using either a pressure or flow sensor. When the ventilator
senses the first patient breathing attempt within the cycle, it
delivers the preset ventilator breath. If the patient fails to initiate a
breath, the ventilator delivers a mechanical breath at the end of
the breath cycle. Additional spontaneous breaths after the first one
within the breath cycle do not trigger another SIMV breath

18. Controlled Mechanical Ventilation
(CMV).
In this mode the ventilator provides a mechanical breath on a
preset timing. Patient respiratory efforts are ignored. This is
generally uncomfortable for children and adults who are
conscious and is usually only used in an unconscious patient.
It may also be used in infants who often quickly adapt their
breathing pattern to the ventilator timing.

19. Pressure Support Ventilation (PSV).
 This was developed as a method to decrease the work of breathing
in-between ventilator mandated breaths. Thus, for example,
SIMV might be combined with PSV so that additional breaths
beyond the SIMV programmed breaths are supported. However,
while the SIMV mandated breaths have a preset volume or peak
pressure, the PSV breaths are designed to cut short when the
inspiratory flow reaches a percentage of the peak inspiratory flow
(e.g. 10-25%). Also, the peak pressure set for the PSV breaths is
usually a lower pressure than that set for the SIMV breath. PSV
can be also be used as an independent mode..

20. Continuous Positive Airway Pressure
(CPAP).
A continuous level of elevated pressure is provided
through the patient circuit to maintain adequate
oxygenation, decrease the work of breathing, and
decrease the work of the heart (such as in left-sided heart
failure - CHF). Note that no cycling of ventilator
pressures occurs and the patient must initiate all breaths.
In addition, no additional pressure above the CPAP
pressure is provided during those breaths. CPAP may be
used invasively through an endotracheal tube or
tracheostomy or non-invasively with a face mask or nasal
prongs

21. Positive End Expiratory Pressure (PEEP)
 is functionally the same as CPAP, but refers to the use of an
elevated pressure during the expiratory phase of the ventilatory
cycle. After delivery of the set amount of breath by the ventilator,
the patient then exhales passively. The volume of gas remaining in
the lung after a normal expiration is termed the functional residual
capacity (FRC). The FRC is primarily determined by the elastic
qualities of the lung and the chest wall. In many lung diseases, the
FRC is reduced due to collapse of the unstable alveoli, leading to a
decreased surface area for gas exchange and intrapulmonary
shunting), with wasted oxygen inspired. Adding PEEP can reduce
the work of breathing (at low levels) and help preserve FRC.

22. Initial ventilator settings
 Tidal Volume, Rate, Pressures and Initial FiO2
 For adult patients and older children
 without existing lung disease -- a tidal volume of 12 mL per kg body weight is set
to be delivered at a rate of 12 a minute (12-12 rule).
 with COPD -- a reduced tidal volume of 10 ml/kg is to be delivered 10 times a
minute to prevent overinflation and hyperventilation (10-10 rule).
 with acute respiratory distress syndrome (ARDS) -- an even more reduced tidal
volume of 6-8 mL/kg is used with a rate of 10-12/minute. This reduced tidal
volume allows for minimal volutrauma but may result in an elevated pCO2 (due
to the relative decreased oxygen delivered) but this elevation does not need to be
corrected (termed permissive hypercapnia)

23. Alarms
Mechanical ventilators are equipped with alarms to notify
you of any changes in their ventilation status. Here are some
of the most common causes of low and high pressure alarm
situations

24. Low-Pressure Alarms
Patient disconnection
Circuit leaks
Airway leaks
Chest tube leaks

25. High-Pressure Alarms
 Patient coughing
 Secretions or mucus in the airway
 Patient biting tube
 Airway problems
 Reduced lung compliance (eg. pneumothorax)
 Increased airway resistance
 Patient fighting the ventilator
 Accumulation of water in the circuit
 Kinking in the circuit
 Problems with inspiratory or expiratory valves