I-TRACH Score to Predict Risk of Prolonged Mechanical Ventilation

  • Intubation in ICU (hospitalized in ICU for >24 hours prior to intubation)
  • Tachycardia (HR > 110)
  • Renal dysfunction (BUN > 25)
  • Acidemia (pH < 7.25)
  • Creatinine (>2.0)
  • decreased HCO3(<20)

*Threshold of 4 or more good Sp and Sn in predicting prolonged mechaniascal ventilation

Note: This study excluded neurological patients and therefore cannot be applied in the NSICU setting.

 

Reference:

Clark, P. A., R. C. Inocencio, and C. J. Lettieri. “I-TRACH: Validating A Tool For Predicting Prolonged Mechanical Ventilation”. Journal of Intensive Care Medicine (2016): pages 1-7.

SETScore for Early Tracheostomy in Stroke

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**APS acute physiology score, LIS lung injury score

 

  • initially an in-house screening tool for tracheostomy prediction
  • performed within 1st 24 hours after admission – use worst value in the first 24 hours
  • Dysphagia either
    • reported from a transferring neurological department or
    • observed by clinical signs on admission
      • non-successful swallowing test
      • impaired saliva handling
      • loss/reduction of gag reflex
    • if already intubated on admission, scored with “0”
  • (Neuro)surgical intervention
    • decompressive surgery, hematoma removal, non-cranial major surgery
    • NOTE EVD or probe placement, thrombectomy, angioplasty for vasospasm or coiling
  • Diffuse lesion = a multilocular or widespread affection of brain (i.e. SAH, brain edema, multiple infarcts, hematomas)
  • hydrocephalus = distension of ventricles requiring EVD
  • total sum ranges between 3 and 37

Previously used (with score of >10) to screen for eligibility to be included in pilot trial of SETPOINT study for early tracheostomy (within 3 days) to standard regimen (late tracheostomy between day7 and day14).

 

 

Reference

Schönenberger, Silvia et al. “The Setscore To Predict Tracheostomy Need In Cerebrovascular Neurocritical Care Patients”. Neurocritical Care 25.1 (2016): 94-104.

 

Pressure-time and Flow-time Graphs

Idealized pressure–time and flow–time graphs for mechanical ventilation. Note that the plateau pressure can be measured when flow returns to zero.

PIP peak inspiratory pressure, Pplat plateau pressure

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Trigger and cycle variables for each of the most common types of conventional mechanical ventilation

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Idealized pressure–time and flow–time graphs with PEEP set above zero for volume-controlled modes of ventilation

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Idealized pressure–time and flow–time graphs with PEEP set above zero for pressure-controlled modes of ventilation

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Idealized pressure–time graph for controlled mandatory ventilation (CMV) with PEEP set above zero. In this mode of ventilation, each breath is triggered after a specified time has elapsed. The breaths can be delivered in either volume controlled (shown) or pressure controlled (not shown), depending on the ventilator settings

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Idealized pressure–time graph for assist control ventilation (ACV) with PEEP set above zero. In this mode of ventilation, each breath is triggered either due to patient initiation (asterisks) or after a specified time has elapsed (no asterisks). The breaths in ACV can be delivered in either volume controlled (shown) or pressure controlled (not shown), depending on the ventilator settings

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Idealized pressure–time graph for intermittent mandatory ventilation (IMV) with PEEP set above zero. In this mode of ventilation, each set breath is triggered after a specified time has elapsed. In addition, the patient can breathe spontaneously between these machine- triggered breaths. The spontaneous breaths create a small relative negative pressure that are depicted in this graph and noted with asterisks. The machine-triggered breaths in IMV can be delivered in either volume controlled (shown) or pressure controlled (not shown), depending on the ventilator settings

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Idealized pressure–time graph for synchronized intermittent mandatory ventilation (SIMV) with PEEP set above zero. In this mode of ventilation, each set breath (or mandatory breath) is synchronized to a patient trigger after a specified time has elapsed. In addition, the patient can breathe spontaneously between the mandatory breaths. The spontaneous breaths create a small relative negative pressure that are depicted in this graph and noted with asterisks. The mandatory breaths in SIMV can be delivered in either volume controlled (shown) or pressure controlled (not shown), depending on the ventilator settings

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Idealized pressure–time graph for synchronized intermittent mandatory ventilation (SIMV) with PEEP set above zero. In addition, pressure support is being applied to the additional patient-initiated breaths between the mandatory breaths

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Idealized pressure–time graph for pressure support ventilation (PSV) with PEEP set above zero. In this mode of ventilation, each breath is triggered by the patient

 

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Reference:

Layon, A. Joseph, Andrea Gabrielli, and William Friedman. Textbook Of Neurointensive Care. London: Springer London, 2013. Print.

 

 

 

 

 

 

Ventilator Settings

1. Mode of ventilation – start with A/C mode, SIMV if tachypneic
2. Tidal Volume – use 8ml/Kg of predicted BW then reduce to 6ml/Kg over next 2 hours
**Monitor peak alveolar pressure (goal </=30cmH20)
**Inspiratory Flow Rate – set at 60mL/min; higher (>/=80mL/min) if respiratory distress or high MV (>/=10L/min)
**I:E ratio – normally >/=1:2, if <1:2 then inc IFR or dec TV or dec RR
3. Respiratory Rate – set at patient’s MV prior to intubation, not to exceed 35 /min; check PCO2 after 30 minutes
4. PEEP – initial PEEP at 5 cmH20
**If with occult PEEP, then increase I:E ratio or ad extrinsic PEEP
5. FiO2 

Obliterative Bronchiolitis

Bronchiolitis Obliterans – used by patho to refer to 2 distinct patterns of small-airway disease

1.  intraluminal polyps in small airways – bronchiolitis obliterans with organizing PNA or cryptogenic organizing PNA

2.  subepithelial inflammatory and fibrotic narrowing of bronchioles – obliterative bronchiolitis or constrictive bronchiolitis

“bronchiolitis obliterans syndrome” 

– occurrence of obstructive vent defect that occurs after transplantation, esp after solid-organ or bone marrow transplantation

Clinical presentation:

– progressive dyspnea and nonproductive cough over weeks to months

– obstructive pattern

Pathogenesis:

– injury and inflammation to small airway epithelial cells and subepith structures lead to fibroprolif, aberrant tissue repair, ineffective epith regen

– a final common pathway

Diagnostics:

PFTs: normal spirometry or slight decrease in FVC, dec FEV1 and reduced FEV1/FVC with poor response to inhaled bronchodilators

Lung volumes indicate air trapping, normal TLC and high RV

subset of patients has normal results on spirometry, a restrictive pattern with low FVC and normal FEV1/FVC or mixed obs/restriction.

DCO2 initially normal

Definition of Oblit Bronchiolitis after lung transplantation (1993, 2002), NIH 2005

CXR: normal; hyperinflation and inc linear or retic markings of airway wall thickening suggestive but nonspecific

HRCT: definitive noninvasive test, patchy decreased lung density with reduced vascular caliber (mosaic perfusion, mosaic attenuation)

advanced cases with dilatation and thickening of large airways characteristic of bronchiectasis

expiratory CT may facilitate early detection (shows air trapping)

characteristic is paucity of ground-glass opacities (seen in PNA or organizing PNA)

Associated Conditions:

– highest in RA

– exposure to inhaled toxins (SO2, HS)

– postinfectious (adenovirus, measles, mycoplasma)

– HSCT – usually within 2 yrs

– lung transplantation

Prognosis:

– natural history is highly variable

Influenza

– H1N1pdm09 pandemic (2009), young and middle-aged low flu vaccine coverage

– sudden fever, cough, rhinorrhea, myalgia –> deteriorate in 4-5d –> hypoxemia, shock, multiorgan dysfunction

Dx:  consider ET aspirate and BAL fluid RT-PCR for patients with RF without etiology (rapid flu tests and IF assays can produce false-negative results)

Tx:  Oseltamivir – empirically ASAP, if contraindicated or resistant, use IV neuramidase inhibitor (zanamivir); empiric broad-spectrum ABx to cover staph (+MRSA), strep PNA, strep pyogenes; consider high dose vasopressors, CRRT, systemic anticoagulation

– early transfer to regional center (ECMO, prone positioning, NM blockade, inhaled NO, lung recruitment maneuvers)

– avoid corticosteroids (higher mortality)

*Lena M. Napolitano et al  JAMA. 2014;311(13):1289-1290. doi:10.1001/jama.2014.2116.