Table 2.
Termination of apnea.
| Reference/study design | Study objects | Detection signals | Stimulation characteristics | DurationStimulation time | Results of stimulation |
|---|---|---|---|---|---|
| Camargo et al. (22) Observational study |
4 infants Gestational age (GA) inclusion: <36.6 weeks Weight inclusion: <2,500 g |
Pulse frequency by oximeter Peripheral oxygen saturation (SpO2) by oximeter |
Instrument: VBW32 skin transducer, audiological engineering Location: thorax Stimulus: 4 s, 250 Hz |
Stimulation: 4 s |
Apnea (HR < 100 bpm, SpO2 < 80% for <35 weeks, HR < 80 bpm, SpO2 < 80% for >35 weeks): Resumption of breathing in 9 of 10 apneic episodes |
| Pichardo et al. (19) Randomized crossover study |
4 infants GA inclusion: >28 weeks Weight inclusion: >1,000 g |
Nasal airflow (AF) HR by chest leads and saturation probe SpO2 Electrocardiogram Thoracic impedance |
Mechanical Instrument: VTS transducer VBW32, audiologic engineering Location: thorax Stimulus: not described Manual No specifications |
Stimulation: 3 s Mode switch: after 12 h or after 5 apneic attacks Duration: 24 h Repetitions: 2× for one infants |
Apnea: Similar effectiveness in ending apneic spells (p = 0.62) Significant decrease in stimulus duration (p < 0.001) Decrease in reaction time to apneic spell (p = 0.058) |
| Lovell et al. (23) Randomized crossover study |
1 infant GA: 28 weeks Weight: 1,280 g Day start study: 7 Treatment: aminophylline, first 2 days on continuous positive airway pressure |
Respiration rate HR SpO2 |
Mechanical Instrument: model 1220 audiological engineering Location: sole of the foot Stimulus: 250 Hz square wave, impedance of 22 Ω (vts) Manual Location: trunk and extremities Stimulus: gentle to vigorous stroking or shaking of the trunk and/or extremities (manual) |
Stimulation: approximately 3 s Mode switch: after 8 h Duration: 16 h Repetitions: three times after 2, 6, and 11 days |
Apnea (>20 s or <20 s + bradycardia/intermittent hypoxia): Similar effectiveness in ending apneic spells (p > 0.05) Decrease in stimulation time of 3.9 s (p = 0.05) Similar reaction time (p = 0.93) Similar time to termination (p = 0.67) Similar apnea duration (p = 0.94) |
| Frank et al. (24) Observational study |
4 infants GA: 31.25 weeks Weight: 1,495.5 g All infants asleep |
Respiration rate by impedance plethysmography | Instrument: balloon with a towel. Location: transversely under the neck Stimulus: 4 psi pressure source, inflation in 0.5 s |
Stimulation: 3 pulses |
Apnea (10 s, sometimes 5 or 15 s): Resumption of breathing in 99 of the 105 apneic episodes |