in the PICU and NICU setting Courtesy from G. Niemann Peter C. Rimensberger, MD Associate Professor Pediatric and Neonatal Intensive Care University Hospital of Geneva Allowable V t depends on pathology and disease severity Volume (l) mild ALI Physiologic Vt in a normal infnant = 6 8 ml/kg!!! Airway pressure (cmh 2 O) severe (A)RDS or pathologies with reduced TLC: - irds - Lung hypoplasia - CDH - Lobar Collapse -Congenital Pneumonia -- Courtesy from G. Niemann Vt of 6 ml/kg bw in a patient with a by 4% reduced TLC corresponds to at Vt of 1 ml/kg, he should therefore receive only 3.6 ml/kg bw! While using lower Vt than physiological the use of higher respiratory rates might become necessary or switching to might be an option Elimination of tidal ventilation Gas transport mechanisms during Slutsky AS ARRD 1988;138:175-83 Bouchut JC et al. Anesthesiology 24; 1:17-12 1
Pressure transmission / : Lung volumes Tracheal pressure Gerstman et al Endinspiration Endexpiration The Paw is used to inflate the lung and optimize the alveolar surface area for gas exchange. Paw = Lung Volume Oxygenation From the lab to the bedside: The principal concepts Oxygenation is primarily controlled by the mean airway pressure (Paw) and the FiO2 for Diffuse Alveolar Disease. The Paw is used to inflate the lung and optimize the alveolar surface area for gas exchange. Paw = Lung Volume Acta Pediatr Japan 1992; 34:494-5 A recruitment procedure during in a preterm infant Lung Recruitment Using Oxygenation during Open Lung High-Frequency Ventilation in Preterm Infants Volume above FRC by respitrace Drop in SO2 Acta Pediatr Japan 1992; 34:494-5 5 1 15 2 25 3 35 Airway pressures De Jaegere Ann et al. Am J Respir Crit Care Med 26: 174; 639 645 2
Lung Recruitment Using Oxygenation during Open Lung High-Frequency Ventilation in Preterm Infants Lung Recruitment Using Oxygenation during Open Lung High-Frequency Ventilation in Preterm Infants before surfactant after surfactant Acta Pediatr Japan 1992; 34:494-5 De Jaegere Ann et al. Am J Respir Crit Care Med 26: 174; 639 645 De Jaegere Ann et al. AJRCCM 26: 174; 639 645 Ventilation Ventilation is primarily determined by the stroke volume (Delta-P) or the frequency of the ventilator. Alveolar ventilation during is defined as: F x Vt Alveolar Ventilation during HFV is defined as: F x Vt 2 Therefore, changes in volume delivery (as a function of pressure-amplitude, frequency, or % inspiratory time) have the most significant affect on CO2 elimination Frequency controls the time allowed (distance) for the piston to move. Therefore, the lower the frequency, the greater the volume displaced, and the higher the frequency, the smaller the volume displaced. Increase amplitude first before decreasing frequency Mean airway pressure, amplitude and frequency MAP (CDP): recruits alveoli/airways and maintains alveolar volume it is closely related to lung volumes and oxygenation Recruit first the lung and then keep open the lung at the lowest pressure necessary! Some bedside rules: Amplitude: there is a close relationship between pressure amplitude and tidal volume tidal volume depends on: 1) the volume displaced by the piston or diaphragm, 2) the resistance of the airways, 3) the compliance of the ventilator circuit, and 4) the patient s lung mechanics therefore: search for visible chest vibrations change amplitude to control ventilation (PaCO2) Acta Pediatr Japan 1992; 34:494-5 1) Lower FiO2 before CDP (=MAP) 2) Always try to define lung closing pressure to assure that you will use lowest pressures required 3) Try to work always the highest frequency possible - increase the amplitude in a first step to correct for high pco2 4) If you re lost - always decrease CDP first! 3
Elective versus Combined Outcome: Death or CLD at 36-37 wks PMA or discharge Elective versus CLD at 36-37 wks PMA or discharge Henderson-Smart DJ Cochrane Database of Systematic Reviews 27, Issue 3. Art. No.: CD14. DOI: 1.12/14651858.CD14.pub2. Henderson-Smart DJ Cochrane Database of Systematic Reviews 27, Issue 3. Art. No.: CD14. DOI: 1.12/14651858.CD14.pub2. 35% 39% NNT 25 in ALI / ARDS in children and adults 3 day mortality in adults 39% 49% NNT 1 Sud S et al. BMJ 21;34:c2327 doi:1.1136/bmj.c2327 Chan KPW, Steward TE Crit Care Med 25; 33:S17 S174 in adults Common strategy during : mpaw was set at 5 cm H2O above the last mpaw measured while receiving CV, the mpaw was then titrated upward at 2 32 cm H2O increments until an FIO2 of.6 or SpO2 of 92% Recruitment attempt All studies showed improvement with How to set initial MAP when switching to 1 9 8 7 6 5 4 3 2 1 5 1 15 2 25 3 35 pressure (cmh2o) volume (ml) 1 9 8 7 6 5 4 3 2 1 5 1 15 2 25 3 35 pressure (cmh2o) Chan KPW, Steward TE Crit Care Med 25; 33:S17 S174 4
in adults 52% (3/58) crossovers 18% (11/61) crossovers arm: Vt of up to 1 ml/kg leading to high Paws (38 ±9 cmh2o) p =.12 Chan KPW, Steward TE Crit Care Med 25; 33:S17 S174 Sud S et al. BMJ 21;34:c2327 doi:1.1136/bmj.c2327 Learning from the experience with in neonates Heterogeneity in trials: HFV vs in infants Ventilation strategies and outcome in randomised trials of HFV Explaining Heterogeneity through Ventilation Strategy Bollen et al. AJRCCM 23; 168: 115 1155 Thome UH Arch Dis Child Fetal Neonatal Ed 25;9:F466 F473 Outcome in subgroups according ventilation strategies Outcome in subgroups according ventilation strategies vs. : BPD @ 36 weeks vs. : BPD or death @ 36 weeks vs. : BPD @ 36 weeks vs. : BPD or death @ 36 weeks? LPVS lung protective ventilatory strategy (?) -strategy : low rate vs. high starting rate (< 6/min) LPVS lung protective ventilatory strategy (?) -strategy : low rate vs. high starting rate (< 6/min) Bollen CW AJRCCM 23; 168:115 1155 Thome UH Arch Dis Child Fetal Neonatal Ed 25;9:F466 F473 Bollen CW AJRCCM 23; 168:115 1155 Thome UH Arch Dis Child Fetal Neonatal Ed 25;9:F466 F473 5
Outcome in subgroups according ventilation strategies vs. : BPD @ 36 weeks vs. : BPD or death @ 36 weeks Does disease severity matter? MOAT II: Survival - PIP 38 cmh2 (post-hoc) 1 Low Vt, higher PEEP LPVS lung protective ventilatory strategy (?) Bollen CW AJRCCM 23; 168:115 1155 Low Vt, higher PEEP according lung inflation and oxygenation -strategy : low rate vs. high starting rate (< 6/min) Thome UH Arch Dis Child Fetal Neonatal Ed 25;9:F466 F473 RR < 6 Proportion of Survivors.9.8.7.6.5.4.3.2 3d p=.19 9d p=.26 CV 1 2 3 4 5 6 7 8 9 Days After Randomization unpublished Courtesy from Derdak S Rescue versus early intervention? Early (< 24 h) versus late (>24 hours) intervention in pediatric ARDS non significant Metha S et al. Crit Care Med 21; 29:136 1369 Fedora M Bratisl Lek Listy 2; 11: 8-13 Time concepts for lung protection The risk to develop ventilator induced lung injury The time concept - Rescue -Early - First Intention - First breath Katzenstein AL et al. Surgical pathology of non-neoplastic lung disease. Saunders, Philadelphia, 1982 Neither a ventilation strategy nor a mode can repair the injured lungs high medium low minimal risk to develop secondary lung injury 6
First Intention HFO with early lung volume recruitment Demographic data and severity of lung disease First Intention HFO with early lung volume recruitment Observational study, historical cohort: 71 premature infants with RDS at birth all patients HFO (n=32) (n=39) p - value Mean airway pressure PaO 2 /FiO 2 ratio Birth weight (g) 981 ± 242 965 ± 254 n.s.* 3 3 Estimated gestational age (weeks) 27.7 ± 2. 27.7 ± 1.8 n.s.* 25 25 HFO Antenatal steroid treatment, no (%) 13 (41) 14 (36) n.s.# APGAR score < 4 at 1 min, no (%) 13 (44) 17 (44) n.s.# APGAR score < 6 at 5 min, no (%) 7 (22) 5 (13) n.s.# Degree of HMD (1-4) on CXR 2.9 ±.8 3 ±.9 n.s.* 2 15 1 5 HFO 2 15 1 5 aa-ratio (first blood gas analysis).16 ±.9.2 ±.16 n.s.* 2 4 6 8 1 12 14 16 18 2 22 24 2 4 6 8 1 12 14 16 18 2 22 24 Values are given as mean ± SD, or as the number (percentage) of patients; * unpaired t-test; ** Chi-square; # Fisher's exact Rimensberger PC et al. Pediatrics 2; 15:122-128 time (h) time (h) Rimensberger PC et al. Pediatrics 2; 15:122-128 First Intention HFO with early lung volume recruitment First Intention HFO with early lung volume recruitment days of ventilation oxygen dependency Survival and CLD Morbidity 1 8 6 4 2 p =.4 HFO 1 8 6 4 2 P <.1 HFO all patients HFO (n=32) (n=39) p - value survivors to 3 days HFO (n=27) (n=35) Ventilation (days) 5 (3-6) 14 (6-23).4 * Oxygen dependency (days) 12 (4-17) 51 (2-6) <.1 * Oxygen at 28 d, no (%) 6 (22) 22 (63).2 # survivors to 36 weeks PCA HFO (n=27) (n=34) CLD; Oxygen > 36 weeks PCA, no (%) () 12 (35).6 # n=3 2 4 6 8 1 12 14 days 2 4 6 8 1 12 14 days Rimensberger PC et al. Pediatrics 2; 15:122-128 Values are given as the median (95% CI) or the number (percentage) of patients; * Mantel-Cox log-rank; # Fisher's exact Rimensberger PC et al. Pediatrics 2; 15:122-128 Recruitment bei der Hyalinen Membranenkrankheit (RDS) 28 wks GA, 8 hours after birth, on, no surfactant received Stepwise increase of MAP MAP 26 cmh 2 O Stepwise decrease of MAP MAP 12 cmh 2 O, Amplitude 4, FiO2.8 MAP 16 cmh 2 O, Amplitude 28, FiO2.21 Ventilation strategy: 1) Deliberate ELR maneuver and optimal continuous distending pressure (CDP) finding 8 1 8 25 2) Early rescue surfactant only when oxygenation response to lung recruitment unsatisfactory (CDP x FiO2 > 5) Acta Pediatr Japan 1992; 34:494-5 7
Tissières P et al. ICM 21 Tissières P et al. ICM 21 Tissières P et al. ICM 21 Tissières P et al. ICM 21 Conclusion: The commonly accepted surfactant indications that were established years ago might need to be reviewed within the context of recently established lung-protective ventilation strategies, thereby providing the rationale for a well-designed randomized trial. Reduced surfactant need with? Variety of acute respiratory failure in children Vento M et al. Intensive Care Med (25) 31:463 47 Moriette G et al. Pediatrics 21;17:363 372 8
in severe airway obstruction in RSV-Bronchiolitis Berner M 2 Intensive Care Med 28 DOI 1.17/s134-8-1151-3 Retrospective review of 9 infants: hypercapnic respiratory failure predominant over-expanded lung pattern none had ARDS MAP IPPV 12.5 cmh 2 O; 18.9 cmh 2 O PaCO 2 fell from 72 to 47 mmhg No paraysis, only sedation Duval E Pediatric Pulmonology 2: 3:35 353 All infants were extubated to CPAP or supplementary oxygen after a mean of 12 hours time course in severe bronchiolitis (n=9) Hickling KG et al. AJRCCM 21; 163:69-78 The beauty of simplicity Mean airway pressure 25 2 15 1 5 : Turn 1 knob and observe 2 parameters (O2, CO2) HFOi HFOm HFOe Post-Extub 1 : chose your allowable Vt 8 Turn then 1 (or 2 knobs) FiO 2 6 4 and observe 3 parameters (O2, CO2, Cdyn) 2 HFOi HFOm HFOe Post-Extub Berner M Intensive Care Med 28 DOI 1.17/s134-8-1151-3 and remember to adapt Ti and Te Time constant: T = Crs x Rrs Acta Pediatr Japan 1992; 34:494-5 9