Effects Of Closed Endotracheal Suction Performed With Hyperoxygenation And/or Recruitment Maneuver On Acute Respiratory Distress Sydrome Piglets

Objective:To assess the impact of closed endotracheal suction performed with hyperoxygenation and /or alveoli recruitment maneuver on pulmonary gas exchange, pulmonary mechanics and hemodynamics in ARDS piglets. Methods:ARDS piglets model was introduced by injection Detergent intratracheally, then piglets were divided into 10cmH₂O positive end expiratory pressure (PEEP) group (n=8) and 5cmH₂O PEEP group (n=8) at random. Four protocols were administered in random order: closed endotracheal suction, closed endotracheal suction with hyperoxygenation, closed endotracheal suction with alveoli recruitment maneuver (ventilation for 10s at 20 cmH₂O PEEP), closed endotracheal suction with hyperoxygenation and alveoli recruitment maneuver. Arterial blood gases, airway pressure and hemodynamic measurements were performed at the following time points: 1 min before suction and 1 min,3min,5min,10 min after suction. Results:There were significant decreases in arterial oxygen partial pressure (PaO₂), arterial blood oxygen saturation (SaO₂ )(p<0.05), pulmonary compliance decreased and mean airway pressure(Pmean), peak airway pressure (Ppeak) , plateau airway pressure(Pplat) increased until 10 min after performing closed endotracheal suction without any assistant maneuve (p<0.05) .At 1 min after Closed endotracheal suction with hyperxygenation, PaO₂ and SaO₂ improved slightly (PEEP 5cmH₂O p>0.05, PEEP 10cmH₂O p<0.05), Ppeak, Pmean, Pplat increased and Cs decreased markedly until 10 min after suction(p<0.05). When performing alveoli recruitment maneuver after closed system suction, Ppeak,Pmean, Pplat decreased and Cs increased significantly (p<0.05), but PaC>2 and SaO2 dropped slightly(p>0.05). At 1 min after closed endotracheal suction with alveoli recruitment maneuver and hyperoxygenation, PaC>2 and SaO2 increased significantly (p<0.05) and kept higher level than baseline until 10 min after suction (p>0.05). Ppeak, Pmean, Pplat decreased and Cs increased significantly until 10 min after suction (p<0.05). MAP and SBP decreased significantly at 1 min after performing 4 protocols (PEEP 5cmH2O p>0.05, PEEP 10cmH2O p<0.05). There were not significant differences in DBP and HR (heart rate) before and after suction between protocols in two groups.In PEEP 5cmH2O group, there was significant difference of PaC>2 between closed endotracheal suction and closed endotracheal suction with hyperoxygenation at 1 min after performing suction (p<0.05).The effects to pulmonary mechanics were different between the protocols with and without alveoli recruitment maneuver (p<0.05). Conclusions:Closed endotracheal suction without any assistant maneuver caused lung collapse loading to impaired gas exchange and stability of respiratory mechanics. After closed endotracheal suction with hyperoxygenation, PaC>2 and SaC>2 increased slightly but respiratory mechanics became obviously worsen. When performing alveoli recruitment maneuver after closed system suction, respiratory mechanics improved but PaC>2 and SaC?2 dropped slightly. Closed endotracheal suction with hyperoxygenation and alveoli recruitment maneuver was a safe protocol for improving oxygenation and respiratory mechanics without harmfull effect founded.