Abstract
Background:
Often conventional ventilation (CV) is utilized in the operating room (OR) for neonatal patients secondary to difficulty ventilating with anesthesia ventilators. However, the shorter circuits on CV can leave little room for procedures. We aimed to evaluate ventilator functionality with the use of an anesthesia ventilator circuit combined with a conventional ventilator in the operating room.
Methods:
In an IRB-exempt bench analysis, a Dräger VN500 ventilator equipped with a Dräger neonatal lung and a Philips NM3 monitor was utilized. Two models were evaluated and set tidal volume (VT) on the Dräger VN500 was validated via the NM3 monitor. Model 1 included a Fisher & Paykel Evaqua 2 infant circuit. Model 2 utilized a Drager Ventstar MRI 300 circuit. In both models, ventilator settings were PC-AC (volume guarantee): VT 6 mL, 15 mL, and 30 mL, respiratory rate 35 breaths/min, Ti 0.3 s, and PEEP of 5 cm H2O. Peak inspiratory pressures (PIP) and inhaled tidal volumes VT were recorded via Dräger VN500 and NM3 monitor.
Results:
In both bench models, tested ventilator performance was within expected specifications (Table 1 and Table 2). While the Drager Ventstar MRI 300 circuit was used in conjunction with the anesthesia ventilator the neo flow sensor cable was unable to support full extension of the circuit which may be necessary during surgical procedures.
Conclusions:
Although our models presented similar results, the neo flow sensor cable was not long enough to be used in conjunction with the anesthesia circuit when fully extended. In the OR, ventilating a patient with an F & P infant circuit with the VN500 and flow sensor is the preferred and safest method of ventilating in a volume targeted mode. An anesthesia circuit without flow sensor may be considered only in pressure targeted modes with caution due to the inability to monitor inhaled VT. The use of an external monitoring device or availability of longer flow sensor cables could aid in supplementing this deficit. Further studies must be completed to evaluate other conventional ventilators on the market.
Table 1 shows the bench study results from the Fisher & Paykel Evaqua 2 infant circuit with infant circuit test leak of 17.7 mL/min and tubing compliance set at 0.8 cmH2O Table 2 shows the Drager Ventstar MDI 300 circuit with anesthesia circuit test leak of 12.6 mL/min and tubing compliance set at 0.5 cmH2O View all access options for this article.Fisher & Paykel Evaqua 2 Infant Circuit (model 1)
Set VT
VTi (NM3)
VTi Percent Difference
PIP (NM3)
Trial 1
6
6.8
13%
14
Trial 2
15
16
7%
34
Trial 3
35
33.4
5%
98.3
Drager Ventstar MRI 300 circuit (model 2)
Set VT
VTi (NM3)
VTi Percent Difference
PIP (NM3)
Trial 1
6
6.4
7%
14
Trial 2
15
15.9
6%
34
Trial 3
35
30.5
13%
85
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