SensorMedics High Frequency Oscillatory Ventilator

The SensorMedics High Frequency Oscillatory Ventilator is a patented high-frequency (>150 R_f) mechanical ventilator by Cardinal Health.^[1] The 3100A model was approved for use in the United States by the Food and Drug Administration in 1991 for neonatal application for the treatment of all forms of respiratory failure; then subsequently approved in 1995 for Pediatric Application, with no upper “weight limit”, for treating selected patients failing conventional ventilation. The High-frequency oscillatory ventilator

Contents 1 3100A 2 3100B 3 Controls and settings 3.1 Bias flow 3.2 Adjust 3.3 Power 3.4 Inspiratory time % 3.5 Frequency 4 Problems 5 References

3100A

The 3100A model is used for infants and children under 35 kilograms (<35 kg).^[2]

3100B

The 3100B model is used for all other people greater than 35 kilograms (>35 kg).^[2]

Controls and settings

Bias flow

Bias flow - Adjusting Bias Flow will affect mean P_aw. Lowering bias flow may decrease work of breathing and facilitate weaning.

Typical ranges

• Premature 8-15 LPM
• Nearterm 10-20 LPM
• Small child 15-25 LPM
• Large Child 20-30 LPM

Adjust

Adjust - Sets the mean airway pressure. This control directly affects lung volume and oxygenation.

Typical ranges

• Initial setting is slightly higher than was observed during conventional ventilation.

Power

Piston displacement is controlled by the power setting. Power changes ventilation and thereby changes blood PaCO2 levels.

Typical values

• Start with a power of 2.0 and adjust for chest wiggle to umbilicus

Inspiratory time %

T_i% is the percentage of time allotted for inspiration. Once this value is set, it is rarely changed.

Typical values

• 33% is recommended by the manufacturer for almost all applications.
• up to 50% is recommended in situations where lung recruitment is necessary.

Frequency

Frequency (R_f) is the number of breaths in one second, expressed in hertz (hz). One hertz is equal to 60 breaths per minute. (R_f)

Typical values and ranges

• The smaller the patient, the higher the frequency.
• The larger the patient, the lower the frequency.

Changes in frequency

• Decrease in frequency = increased tidal volume.
• Increase in frequency = decreased tidal volume.

Problems

Since neither the 3100A or the 3100B measure actual tidal volumes, it is impossible to wean with precision;^[3] some clinicians find this to be problematic in the application of oscillatory ventilation.^[3]

References

1. ^ Messier SE, Digeronimo RJ, Gillette RK (2009). "Comparison of the Sensormedics 3100A and Bronchotron transporter in a neonatal piglet ARDS model.". Pediatr Pulmonol 44 (7): 693–700. doi:10.1002/ppul.21041. PMID 19499589. 
2. ^ ^{a b} Custer JW, Ahmed A, Kaczka DW, Mulreany DG, Hager DN, Simon BA et al. (2011). "In vitro performance comparison of the Sensormedics 3100A and B high-frequency oscillatory ventilators.". Pediatr Crit Care Med 12 (4): e176-80. doi:10.1097/PCC.0b013e3181fe3028. PMID 21037502. 
3. ^ ^{a b} Scott CJ, McGeorge AD, Hancock SW (1997). "Failure of adequate ventilation using Sensormedics 3100A High Frequency Oscillatory Ventilator.". Paediatr Anaesth 7 (5): 432. PMID 9308072.