ICU Psychosis
A psychotic state entered into by some ICU patients, perhaps as a  result of medication(s) used in the ICU or as a defense mechanism or other response to the trauma involved in the stressful ICU setting; often characterized by hallucinations, visual and/or auditory, and lack of ability to recognize reality.

From an unknown cause (etiology); see Pulmonary Fibrosis.

Induced Coma/Deep Sedation
Use of narcotic medications to produce complete loss of consciousness.

Induced Paralysis
State of complete physical barrier to movement of the body's muscles induced using tubocurarine, a substance derived from the crude extract, curare.

Inspiratory time
The time set between breaths on a mechanical ventilator.  Inspiratory time is normally set between 0.3 and 0.6 seconds.

Inspiratory to expiratory ratio (I:E ratio)
The ratio of the inspiratory to the expiratory times; normal I:E ratios are 1:1, 1:1.5, and 1:2.

Spaces (a place between).

Situated in the interstices of a part; distributed through the connective tissue.

Interstitial pneumonia(s)
A pneumonia centered in the interstitium, the tissue which lines and supports the aleveoli.   For further information and discussion, see What-Is-Insterstitial Pneumonia? In the What-Is? Section.

Tissue which lines and supports the alveoli.

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Mean airway pressure (MAP or Paw)
The mathematical average of all the different pressures being used by the ventilator to support the infant. MAP is expressed in cm H2O. A level of 20 cm H2O indicates severe disease and a level of 10 cm H2O suggests that the neonate may be ready to be weaned from the ventilator.

Multiple Organ Dysfunction Syndrome (MODS)
Presence of altered organ function in an acutely ill patient such that homeostasis cannot be maintained without intrervention.

Multiple Organ Failure (MOF)
The complete shutting down of multiple organs throughout the body.

Muscle atrophy
Loss of muscle tissue, strength and structure resulting from non–usage.


Nitric Oxide (NO)
Chemical compound used in ventilating a patient believed to make breathing easier in some ARDS patient and assist in combating the effects of the inflammatory process in ARDS.  See article on Nitric Oxide in the Learn About ARDS Section 1 for further information and discussion.  Also see, Therapeutic Role Of Nitric Oxide In Respiratory Disease, Thomas E. Siddons, BSc, Mohammed Asif, MA, BMBCh, FRCS, and Tim W. Higenbottam, MD, MA, BSc, FRCP, University of Sheffield, Sheffield, United Kingdom    Medscape Respiratory Care 4(2), 2000; Inhaled nitric oxide therapy is successful in treating ARDS, PPH, and PPHN because it reduces pulmonary artery pressure and vasodilates the blood vessels in the ventilated regions of the lung; on-line web address for article at Medscape:




O2Sat Level
Oxygen saturation level in the blood

Deficient urine output.

Oxygenation index (OI)
A frequently used calculation that incorporates FiO2, Paw, and PaO2. The OI is generally between 30-40 in the presence of severe respiratory distress. OI is calculated as follows:

OI = FiO2 x Paw x 100

Oxygen partial pressure (PO2)
Refers to the pressure exerted by oxygen when dissolved in liquid.


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