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Respiratory Management (Rehab Phase)

Intermittent Hypoxia

Intermittent hypoxia is usually studied as a complication contributing to other medical problems, including sleep-disordered breathing. However, it can also be used as a training protocol to improve somatic motor function and increase growth factor expression in the central nervous system (CNS) (Dale et al. 2014). Complication rates, cost, and quality of life are among the many important factors to consider in all forms of assisted ventilation training.

Author Year; Country
Research Design
Total Sample Size
Methods Outcome

Tester et al. 2014; United States
Controlled Trial

Population: N=8 incomplete SCI
individuals (4M 4F)
Mean age (SD): 53.1(10.9)
Mean DOI (SD): 5.1(1.7) years
AIS-A/C/D: 1/2/5
6 cervical, 2 thoracic
10 days of intermittent hypoxia
Outcome Measures:
Minute ventilation (MV), tidal volume, forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), tidal volume, breathing frequency
  1. Significantly increased tidal volume during recovery in IH than that in sham protocol compared to baseline*
  2. Increased FVC and FEV1 in 4 individuals after 10 days, 3 showed no change, 1 showed decline
  3. Increase in MV significantly associated between increase in tidal volume & breathing frequency during recovery period after IH session
  4. No significant difference in MV, tidal volume, and breathing frequency in recovery periods and baseline* periods over 10 days of intervention, respectively

*values before each IH session, under supplemental CO2

Sankari et al. 2015; United States
Controlled Trial

Population: N=24 SCI and able-bodied individuals
Mean age (SD): 38.9 (15.9)
Mean DOI* (SD): 12.9 (6.2)
AIS-A/C/D: 14/1/1
8 cervical SCI (CSCI), 8 thoracic SCI (TSCI), 8 able-bodied (AB)
*Applicable to CSCI & TSCI groups only
Acute intermittent hypoxia (AIH, 15 episodes of 1 min) & sham protocol on each subject
Outcome Measures:
Minute ventilation (VE), tidal volume (VT), and cardiovascular measures
  1. Significantly increased VE during hypoxia
  2. Significantly increased VE* in CSCI patients only
  3. Significantly increased VE variability* in TSCI patients only
  4. No significant change in VE & VE variability in sham protocols*
  5. Significantly higher VE variability at baseline and recovery in CSCI patients compared to TSCI and AB
  6. Significantly increased VT* in CSCI & TSCI patients
  7. Significantly greater increase in VT* in CSCI compared to TSCI

*During posthypoxic recovery compared to baseline

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