The Functional Status Scale (FSS) for Pediatric Hospitalization Outcomes: A Tool for Researchers

NICHD-funded research scale helps measure functional status of children during hospital admissions

Measuring children’s outcomes in a consistent and reliable manner can be difficult, especially for large pediatric studies, which enroll children with diverse health problems and ages. Researchers in NICHD’s Collaborative Pediatric Critical Care Research Network (CPCCRN) developed the FSS to more easily and consistently evaluate the functional status of hospitalized children.

Developing the Scale

A team of NICHD-funded researchers developed the FSS to overcome gaps common to existing pediatric outcome measurements, which tend to use death as the primary outcome, are too time-consuming and subjective, or apply to only a limited ages or setting. The FSS is easy and fast to use, minimally subjective, and applicable to a broad age range in a variety of hospital environments.

The study team enrolled 836 pediatric patients and used the Adaptive Behavior Assessment System II to calibrate and then validate the FSS scale. The patients included children admitted to the pediatric intensive care unit (PICU), those not in the PICU but at high risk, and children with chronic diseases who require specialized medical equipment (also called technology-dependent).

The study team included different pediatric health specialists—pediatricians, neurologists, developmental psychologists, physiatrists and rehabilitation specialists, nurses, intensivists and critical care doctors, respiratory therapists—from 11 institutions.

FSS at a Glance

FSS is an objective, rapid, quantitative, and reliable tool to assess functional status in all children from full-term newborns to adolescents. Conceptually, the scale is based on activities of daily living scales, which are used in adult studies to evaluate functioning, disability, and dependency. It is important to note that the FSS is not designed to predict long-term outcomes. Furthermore, the FSS should not be used to assess or predict outcomes for individual pediatric patients.

The FSS examines 6 domains of functioning, and each domain receives a score of 1 (normal), 2 (mild dysfunction), 3 (moderate dysfunction), 4 (severe dysfunction), or 5 (very severe dysfunction). Final scores range from 6 to 30. With training, nurses, therapists, or physicians can collect FSS data.

You can view an FSS Table to learn more about the scale and the data. In addition, an operations manual for researchers will be available through the CPCCRN.

Functional Domain: Mental Status

1) Normal: Patients have normal wake and sleep periods and appropriate responsiveness.

  • Awake = awareness with behavior appropriate for age
  • Sleep = restful state without over-reaction, such as crying or agitation, to noises in the environment
  • Aware, alert, and responsive to self and the environment

2) Mild Dysfunction: Patients are sleepy but can be aroused with noise, touch, or movement.

  • Sleeps more than is age appropriate
  • Continues sleeping unless aroused
  • Also refers to:
    • Decreased responsiveness to social interaction, and/or
    • Inability to consistently focus on or follow a person or object that crosses the field of vision

3) Moderate Dysfunction: Patients are lethargic (drowsy, sluggish, or unusual lack of energy) and/or irritable.

  • Arousable, but returns to a sleep-like state without frequent stimulation
  • Irritable infants may be inconsolable with increased sensitivity to stimulation and a high-pitched cry reaction.

4) Severe Dysfunction: Patients are in a stupor and difficult to arouse.

  • Decreased or impaired consciousness
  • Marked reduction to environmental stimuli
  • Little to no eye contact
  • Responses to unpleasant stimuli diminished, poorly organized, or a withdrawal

5) Very Severe Dysfunction: Patients are unresponsive, in a coma, and/or vegetative state.

  • Coma = deep or profound state of unconsciousness from which the individual cannot be aroused
  • Vegetative state = no evidence of awareness of self or the environment
  • Does not sense or react to internal or external stimuli
  • May wake intermittently but remains unresponsive

Functional Domain: Sensory Functioning

1) Normal: Patients have intact hearing and vision.

  • Intact hearing = moves eyes and/or head toward sound stimuli
  • Intact vision = turns gaze to focus on people or objects that cross visual field
  • Responsiveness to touch not impaired

2) Mild Dysfunction: Patients have suspected hearing or vision loss.

  • Suspected hearing loss = inconsistently pays attention to sound
  • Suspected vision loss = inconsistently focuses on movement
  • Responsiveness to touch not impaired

3) Moderate Dysfunction: Patients are not reactive to auditory or visual stimulation.

  • Lack of evidence of hearing or lack of evidence of vision
  • Responsiveness to touch not impaired

4) Severe Dysfunction: Patients are not reactive to both visual and auditory stimulation.

  • Lack of evidence of hearing
  • Lack of evidence of vision
  • Responsiveness to touch not impaired

5) Very Severe Dysfunction: Patients do not respond normally to touch or pain.

  • Lacks purposeful or semi-purposeful movement
  • Withdrawal or spinal reflex

Functional Domain: Communication

1) Normal: Patients make age-appropriate, non-crying sounds and interactive facial expressions or gestures.

  • Vocalization is age-appropriate:
    • Infants create sounds to make presence known
    • Children use words to convey needs
  • Interactive facial expressions and gestures are non-verbal communication, often associated with emotion

2) Mild Dysfunction: Patients are less likely to make sounds, facial expressions and/or show social responsiveness.

  • Decreased social expression (facial or verbal)
  • Decreased socialization

3) Moderate Dysfunction: Patients do not express attention-getting behavior.

  • Does not demonstrate "Look at me, here I am" behaviors
  • May initiate attention-getting behavior but cannot communicate needs

4) Severe Dysfunction: Patients do not demonstrate discomfort.

  • May not cry or cries very little during painful or uncomfortable procedures

5) Very Severe Dysfunction: Patients do not communicate.

  • No communication using voice, body posture, or facial expression
  • Does not express physiological or psychological needs

Functional Domain: Motor Functioning

1) Normal: Patients have coordinated body movements, normal muscle control, and awareness of action.

  • Normal muscle control
  • Coordinated body movements
  • Awareness of action and its purpose:
    • Infants can hold a rattle and transfer it between hands
    • Toddlers can carry objects, hold stuffed animals, suck thumbs
    • Children can write or play with toys

2) Mild Dysfunction: Patients have 1 limb that is functionally impaired, either partially or a complete loss of function.

  • Impairment may be caused by medical devices such as restraints, intravenous boards, bandages, or casts
  • Impairment may be caused by physical issues such as deformities, weakness, stiffness, spasticity, and/or movement disorders
    • Performs age-appropriate activities but with increased effort
    • Weakness = patient cannot move a limb off a surface, against gravity, while holding an object or against resistance
    • Stiffness = at least 1 limb has increased resistance to passive motion but is held in normal positions; stimulation does not result in flexion, extension, or arching

3) Moderate Dysfunction: Patients have at least 2 limbs that are functionally impaired, either partially or a complete loss of function.

  • Impairment may be caused by medical devices such as restraints, intravenous boards, bandages, or casts
  • Impairment may be caused by physical issues such as deformities, weakness, stiffness, spasticity, and/or movement disorders
    • Performs age-appropriate activities but with increased effort
    • Weakness = patient cannot move a limb off a surface, against gravity, while holding an object or against resistance
    • Stiffness = at least 1 limb has increased resistance to passive motion but is held in normal positions
    • Spasticity = increased muscle tone with involuntary movement

4) Severe Dysfunction: Patients have poor head control.

  • Poor head control = decreased ability to hold the head upright at 90 degrees and cannot hold the head still at less than 90 degrees
  • If the body is supported, the head falls back, to the side, or to the front
  • If sitting, patient cannot bring head to the upright position
  • If supine or prone, patient cannot bring head to the midline position

5) Very Severe Dysfunction: Patients are paralyzed or display abnormal posturing (decerebrate, decorticate)

  • Paralysis = loss of voluntary motor function and abnormal muscle tone
  • Decerebrate posturing = rigid extension of all extremities, with internal rotation
  • Decorticate posturing = rigid flexion of upper extremities, with clenched fists and straightening of lower extremities
  • Mental status may be preserved or altered

Functional Domain: Feeding*

1) Normal: Patients consume all food by mouth, with age-appropriate help.

  • No parenteral or gavage feeding
  • Energy (caloric) content is not taken into account

2) Mild Dysfunction: Patients are under medical instructions to withhold food and fluids (NPO, or no food by mouth) or require specialized food (higher energy or density) that is consumed orally.

  • No parenteral or tube feeding
  • Increased-density oral feeding involves special formulas and/or additions to the diet

3) Moderate Dysfunction: Patients need age-inappropriate help to consume food.

  • Feeding by a caretaker or use of a feeding aid (e.g. bottle) at an inappropriate age

4) Severe Dysfunction: Patients require a feeding tube (nasogastric, orogastric, or small-bowel tubes).

  • Feeding tube with or without parenteral nutrition, which is administered intravenously and has a dextrose concentration greater than 5 percent

5) Very Severe Dysfunction: Complete parenteral nutrition.

  • Patients receive all nutrition intravenously, through a peripheral or central vein.

*Dextrose solutions greater than 5% are not considered parenteral nutrition.

Functional Domain: Respiratory Status

1) Normal: Patients breathe room air without support or aid.

  • No artificial support or aid is required

2) Mild Dysfunction: Patients need oxygen and/or suctioning.

  • Oxygen is supplied through any apparatus (e.g. blow-by system, cannula, face mask)
  • Suctioning refers to oral or tracheal suctioning

3) Moderate Dysfunction: Patients had a tracheostomy.

  • Tracheostomy = incision in the windpipe created to relieve an obstruction to breathing

4) Severe Dysfunction: Patients need mechanical ventilator support for part of the day, and/or need continuous positive airway pressure for all or part of the day

  • Continuous positive airway pressure treatment for all or part of the day, provided through a face mask or tracheostomy
  • Mechanical ventilator support for part of the day, including positive or negative pressure ventilation devices

5) Very Severe Dysfunction: Patients require mechanical ventilator support all day and night.

  • Mechanical ventilator support all day and night, including positive or negative ventilation devices

Reference

Pollack MM, NICHD Collaborative Pediatric Critical Care Research Network, et al. Functional Status Scale: New Pediatric Outcome Measure. Pediatrics DOI: 10.1542/peds.2008-1987 (2009).