The Babylog 8000 plus with Pressure Support and Volume Guarantee The Key to Breathing Harmony

Babylog 8000 plus Comprehensive modes: CPAP, IMV, SIMV, A/C, PSV A ventilator designed specifically for critically ill newborn infants Comprehensive modes: CPAP, IMV, SIMV, A/C, PSV Volutrauma protection strategy: Volume Guarantee option in SIMV, A/C, and PSV modes Leak- adapted flow synchronization

PSV with Differences First the Similarities: Pressure targeted breath (both spontaneous and set) Flow terminated at 15% of peak inspiratory flow Inspiratory time will vary and is patient dependent Preset Insp. Time still functions as a back-up, breath will not exceed clinician setting

PSV with Differences Now the big differences: A “back-up” rate is set - so yes, in theory a paralyzed patient can be placed on PSV, Babylog style All breaths, whether patient assisted or not will be pressure targeted and flow terminated PSV may be combined with the volume guarantee (VG) option – allowing clinicians to set tidal volume

Pressure Support Ventilation (PSV) Patient or vent ilator initiated Set Pinsp Paw Peak flow insp V • Drop to 15% of peak flow Pressure support is a mode used successfully in spontaneously breathing adults and older children. As pressure builds with volume delivery to the lungs, flow tapers off. When flow drops to 15% of peak value, the ventilator ends inspiration. In other words, the ventilator adjusts inspiratory time based on near- zero flow, similar to what we tried to do manually. The ventilator, however, can do it for each breath as it happens. Patient or vent ilator initiated inspiration exp PSV cycled expiration

Pressure Support Ventilation with leak compensation Flow termination automatically compensates for leak Onset of inspiration expiration Leak flow The Babylog pressure support mode compensates for leak flow, keeping the flow criterion to end inspiration intact.

Examples courtesy of Prof. JC Rozé, Nantes, France Patient- Set Inspiratory Time in Neonatal Pressure Support Ventilation (PSV) Examples courtesy of Prof. JC Rozé, Nantes, France The average Inspiratory Time of the four patients on PSV above was ~ .25seconds – expect to see shorter I times, and consequently a drop in the MAP

Why let the infant end inspiration (set Tinsp ) ? CBF variability increases IVH risk Perlman , et al. N Engl J Med 1983 CBF variability and IVH increases with infant- ventilator asynchrony Perlman , et al. N Engl J Med 1985 Rennie, et al. Arch Dis Child, 1987 So, harmonizing ventilator- infant interaction should reduce IVH.

Why give mechanical support for all breaths? Decreases Work of Breathing Jarreau, Moriette, Mussat, et al; Am J Resp CCM, Mar 1996 Decreases Oxygen Consumption Roze, Liet, Gournay, Debillon, Gaultier; Eur Resp J, Nov 1997 Reduced Stress Hormone Levels Quinn, de Boer, Ansari, Baumer; Arch Dis Child, May 1998 Decreased Effort and Respiratory Rate Bendel- Stenzel, Bing, Meyers, Connett, Mammel; Ped Res, May 1998 Less Variation in Vt After Surfactant Mrozek, Bendel- Stenzel, Meyers, Bing,, Mammel; Ped Res, May 1998

Problems with a Preset Ti: Patient Asynchrony The infant attempts to breathe during a set ventilator inspiratory cycle, resulting in lower lung pressure and excessive volume.

Volume Guarantee: How does it work? The VG option allows for delivery of a set volume during mandatory pressure breaths in A/C, SIMV, and PSV Similar to Autoflow on the Dura, the PIP will adjust automatically up to a set maximum, compensating for changes in resistance and/or compliance, to ensure the set tidal volume is delivered The inspiratory Pressure knob now functions as the maximum pressure allowed, NOT the set PIP. PIP is not set, and will vary.

Problems with Volume Guarantee Similar to autoflow, high respiratory demand from the patient will result in a lower PIP delivered to the airway, i.e. less support for the patient. PATIENTS MUST BE CLOSELY MONITORED FOR SIGNS OF INCREASED WOB WHEN UTILIZING THE VOLUME GUARENTEE MODE!

Postulated mechanism of action: Why volume - oriented ventilation ( VOV ) in infants? VOV vs SIMV: Equivalent ventilation at lower MAP Herrera, at al. Ped Res 1999 VOV reduces IVH, acute lung injury Rosen WC, et al. Ped Pulm 1993 Sinha SK, et al. Arch Dis Child Fetal Neo Ed 1997 Postulated mechanism of action: Consistent Vt Stable PaCO2 Stable CBF Less IVH

Why volume - oriented ventilation ( VOV ) in infants? Pressure ventilation may cause hypoventilation or overdistention when CL changes Davis, et al. N Engl J Med 1988 Gibson, et al. Eur J Pediatr 1994 Bjorklund, et al. Am J Respir Crit Care Med 1996 Dimitriou, et al. J Perinat Med 1997 Lung overdistention creates acute / chronic lung injury Herandez, et al. J Appl Physiol 1989 Bjorkland, et al. Ped Res 1997 Variable PaCO2 in pressure ventilation increases IVH Stewart, et al. Pediatrics 1981

Pressure Support Mode with Volume Guarantee : Concept of “Autoweaning” PIP C lung Vt Extubate! Time So far I’ve talked about ventilatory support of infants when they are acutely ill with respiratory distress. What about weaning from the ventilator? Unlike adults, I think that preterm infants don’t become ventilator- dependent as long as our ventilator management can keep up with the infants’ improving lung function. I think using the pressure support mode with VG can make this easy for us. As lung function improves over time, the ventilator will reduce inflation pressure to maintain the set tidal volume. The infant will control rate and inspiration time throughout. We’ll have a backup rate set in case of central apnea episodes. There comes a point where the pressure won’t change much; as it is primarily overcoming ETT resistance. Then the infant should be extubated. If apnea remains a problem, at least we are delivering the least mechanical force for adequate ventilation. This is theoretical; we need clinical trials to prove it.

Tidal volume delivery in mechanically ventilated preterm infants Appropriate tidal volume for mechanical ventilation of preterm infants with surfactant deficiency is 4 - 6 mL/ kg body weight.

A Happy Child PSV+VG

Two Extra Pictures - The Neonatal flow sensor Hot wire anemometer Sensitive to 0.17 mL 0 - 30 lpm range Weighs 10 grams 0.5 mL added deadspace Inexpensive 6 month use

Flow Sensor Measurement Principle Hot wire anemometer: Two tiny platinum wires are heated to 400°C One wire is shaded to determine direction of gas flow Wire cooling is proportional to gas flow Flow is integrated with time for volume measurement