II. Definitions
- Negative Inspiratory Flow (NIF) or Maximal Inspiratory Pressure (MIP)
- Maximal inspiratory effort measured as the pressure generated against an occluded airway
- Maximal Inspiratory Pressure (MIP) and Negative Inspiratory Flow (NIF) represent the same measure
- MIP is typically reported as positive, while NIF is reported as negative
III. Indications
- Progressive Neuromuscular Disease (e.g. Guillain Barre Syndrome, Myasthenia Gravis)
- Ventilator Weaning
IV. Interpretation: Findings of Impending Respiratory Failure
- Physical findings
- Quantitative Tests
- Single Breath Counting <10 to 15
- Vital Capacity <15-20 ml/kg
- Tidal Volume <5 ml/kg
- Maximum expiratory force <40 cm H2O (normal may be as high as 100 cm H2O)
- Negative Inspiratory Flow (NIF) less negative than -20 to -30 cm H2O (normal may be < -100 cm H2O)
- NIF less negative than -25 cmH2O may predict Ventilator Weaning failure
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Related Studies
| Concepts | Organ or Tissue Function (T042) |
| SnomedCT | 64231002 |
| English | Inspiratory force, function, inspiratory force, Inspiratory force, Inspiratory force, function (observable entity), Inspiratory force (function) |
| Spanish | esfuerzo inspiratorio (entidad observable), esfuerzo inspiratorio (función), esfuerzo inspiratorio, fuerza inspiratoria |
Ontology: Respiratory muscular pressure (C0231900)
| Concepts | Finding (T033) |
| SnomedCT | 24296009 |
| English | P MUS, P<sub>MUS</sub>, Respiratory muscular pressure, P>MUS<, Respiratory muscular pressure (observable entity) |
| Spanish | presión muscular respiratoria (entidad observable), presión muscular respiratoria |
