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Comparison of SIMV+PS and AC modes in chronically ventilated children and effects on speechg
Eugene Y Sohn1,2, Katy Peck3, Rory Kamerman-Kretzmer4
1Division of Pediatric Pulmonology and Sleep Medicine, Children's Hospital Los Angeles, USC Keck School of Medicine, Los Angeles, CA.
Insights
Assist Control (AC) and Synchronized Intermittent Mandatory Ventilation with Pressure Support (SIMV+PS) for home mechanical ventilation (HMV) in children showed few differences. AC may offer slightly easier speech, but abnormal speech patterns persist in HMV patients.
Area of Science:
- Pediatric critical care medicine
- Respiratory physiology
- Speech-language pathology
Background:
- Chronic home mechanical ventilation (HMV) via tracheostomy is common in children.
- Assist Control (AC) and Synchronized Intermittent Mandatory Ventilation with Pressure Support (SIMV+PS) are primary ventilation modes.
- No prior studies have directly compared AC and SIMV+PS in this pediatric population.
Purpose of the Study:
- To compare the physiological and speech outcomes of AC versus SIMV+PS in children on chronic HMV.
- To assess patient comfort and speech performance on both ventilation modes.
Main Methods:
- A blinded study involving 15 children (mean age 12.3 years) on HMV.
- Participants underwent speech testing and physiological monitoring (SpO2, PETCO2, HR, RR, respiratory pattern) on both AC and SIMV+PS modes.
- Subjective questionnaires evaluated comfort, breathing ease, and speech ease.
Main Results:
- No significant differences in oxygen saturation, PETCO2, heart rate, or respiratory rate between modes.
- AC mode showed a significantly lower maximum heart rate (p=0.047) and less spontaneous breathing above the set rate (p=0.029).
- Subjects reported significantly easier speech on AC, though objective speech testing showed no difference; abnormal speech cadence was observed in many.
Conclusions:
- Few significant clinical differences exist between AC and SIMV+PS for pediatric HMV.
- AC may offer a subjective advantage in speech ease, though objective measures and speech patterns require further investigation.
- Abnormal speech patterns are prevalent in children requiring HMV, irrespective of the ventilation mode studied.
Background:
Two modes of ventilation commonly used in children requiring chronic home mechanical ventilation (HMV) via tracheostomy are Assist Control (AC) and Synchronized Intermittent Mandatory Ventilation with Pressure Support (SIMV + PS). There has been no study comparing these two modes of ventilation in children requiring chronic HMV.
Methods:
We studied children requiring HMV capable of completing speech testing. Study participants were blinded to changes and studied on both modes, evaluating their oxygen saturation, end-tidal carbon dioxide (PETCO2), heart rate, respiratory rate, and respiratory pattern. Subjects completed speech testing and answered subjective questions about their level of comfort, ease of breathing, and ease of speech.
Results:
Fifteen children aged 12.3 ± 4.8 years were tested. There was no difference in mean oxygen saturation, minimum oxygen saturation, mean PETCO2, maximum PETCO2, mean heart rate, and mean respiratory rate. The maximum heart rate on AC was significantly lower than SIMV + PS, p = .047. Subjects breathed significantly above the set rate on SIMV + PS (p = .029), though not on AC. Subjects found it significantly easier to speak on AC, though there was no statistically significant difference in speech testing. Four subjects had multiple prolonged PS breaths on SIMV + PS. Many subjects exhibited an abnormal cadence to speech, with some speaking during both inhalation and exhalation phases of breathing.
Conclusions:
There were few differences between AC and SIMV + PS, with a few parameters favoring AC that may not be clinically significant. This includes the subjective perception of ease of speech. We also found unnatural patterns of speech in children requiring HMV.
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