The Influence Of Different Mechanicalventil Ation Modes And Breathing Machine Parameters On Haemodynamics

Purpose: To discuss the influence of different mechanical ventilation mode and breathing machine parameters on haemodynamics by observing the relationship between different mechanical ventilation mode and breathing machine parameters and noninvasive haemodynamic monitoring. To guide fluid resuscitation and provide theory support to the use of breathing machine to cure the respiratory failure of the neonate and raise the neonatal cure rate.Method: Use 2 pigs which were born within 24 hours. Cut the umbilical cords off. After anesthesi, cut their trache and umbilical veins and arteriaumbilicalis. And then place pipes and use Respirator assisted ventilation,etc. Under the conditions of Fi O2=1.0 and Pa O2 < 100 mm Hg, use warmsaline to lavage the alveolus pulmonis repeatedly. Making it stable forone hour and announce the success of the making of lung injury model[1].Lung injury animal model animals are divided into 2 groups of one,labeled A and B respectively. Implement normal frequency mechanical ventilation to pig A firstly(oxygen concentration: 30%; PIP: 15 cm H2O)Increase PEEP from 0 cm H2 O with 1 cm H2 O at a time(tidal volume: 5 ~ 8ml/k;IE ratio:1:2).Pay attention to the stability of the vital signs and the ventilation lasts about5 minute. When the data is stable, record the hemodynamic index which is under different airway pressure. Later, fix the PEEP to 5cm H2 O and PIP to 18 cm H2O.Increase PIP, 2cm H2 O at one time,with intervals of 5 minutes, gradually to 34 cm H2O.Record the hemodynamic index of PIP18、PIP22、PIP26、PIP30、PIP34 respectively. Modify it with conventional mechanical ventilation(oxygen concentration: 30%;frequency: 12Hz; IE ratio: 33%) Firstly, set mpaw to 5cm H2 O.Then increase it,1cm H2 O at one time, with intervals of 5 minutes, gradually to 22 cm H2O.Record the hemodynamic index under different airway pressure.The pig B,instead, implement High frequency oscillatory ventilation experiment first and then normal frequency mechanical ventilation. Set the parameters the same as those in the last experiment. Repeat it 3 times and record the average data.Inject luminal into all the experiment animals and diazepam maintains Sedation condition. Use thoracic electrical bioimpedance to continuously monitor the hemodynamic index, including CI 、SVV 、HR 、SBP、DBP、MABP、 CVP and so on.Result:1、Under normal frequency mechanical ventilation, the increase of CVP、SVV and PEEP is positively associated and the increase of CI and PEEP is negatively associated. The increase of HR and PEEP is positively associated. When PEEP is over than 10 cm H2O, CI begins to lower than normal and when PEEP is 15 cm H2O, CVP and SVV begin to appear abnormal.With the increase of PIP, SBP and CI drop, and SVV increase gradually, DBP doesn’t show any apparent change when PIP is from 18 to30 cm H2O;however,when PIP is up to 30 cm H2O, DBP begins to appear abnormal, until PIP over than 34 cm H2O,DBPobvious wave.2、Under normal frequency mechanical ventilation, when PEEP is from0 to 10 cm H2O and PIP is from 18 to 26 cm H2O, the hemodynamic index doesn’t show any apparent change. When PEEP waves between 10 and15 cm H2O and PIP waves between 26 and 30. It has a small influence on haemodynamics.When PEEP is 20 cm H2O and PIP is over 34 cm H2O, HR 、MABP 、 CI 、 SVV and CVP are obviously abnormal and haemodynamics shows obvious wave.3 、 Under HFOV, CVP and SVV increase with the increase of average airway pressure and the amplitude of variation is smaller than that under normal frequency mechanical ventilation. When m Paw is between 5 and15 cm H2O, Hemodynamic Parameters are stable. When it is over 15 cm H2O,Hemodynamic Parameters wave slightly. When it is 20 cm H2O or more,Hemodynamic Parameters wave obviously. CI drops with the increase of average airway pressure, but amplitude of variation is almost the same as that under normal frequency mechanical ventilation.Conclusion: 1 、 Under normal frequency mechanical ventilation, the increase of CVP 、 SVV and PEEP is positively associated( r CVP=0.903 、r SVV=0.922,P=0);The increase of CI and PEEP is negatively associated(r CI=-0.913,P=0); The increase of HR and PEEP is positively associated(r HR=0.401,P=0.028);when PEEP is 15 cm H2O, CVP and SVV begin to appear abnormal. With the increase of PIP, SBP and CI drop, and SVV increase, but DBP doesn’t show any apparent change when PIP between 18 to30 cm H2O, until PIP over than 34 cm H2O,DBPobvious wave.2、Under normal frequency mechanical ventilation, when PEEP is from0 to 10 cm H2O,the hemodynamic index doesn’t show any apparent change.When PEEP waves between 10 and 15 cm H2O,it has a small influence on haemodynamics.When PEEP is 20 cm H2O, HR、MABP、CI、SVV and CVP are obviously abnormal and haemodynamics shows obvious wave. when PIP is from 18 to 26 cm H2O, it has a small influence on haemodynamics. When PIP waves between 26 and 30. It has a small influence on haemodynamics.When PIP is over 34 cm H2O, Hemodynamic Parameters show obvious wave.3 、 Under HFOV, CVP and SVV increase with the increase of average airway pressure and theamplitude of variation is smaller than that under normal frequency mechanical ventilation.When m Paw is between 5 and15 cm H2O, Hemodynamic Parameters are stable. When it is over 15 cm H2O,Hemodynamic Parameters wave slightly. When it is 20 cm H2O or more,Hemodynamic Parameters wave obviously. CI drops with the increase of average airway pressure, but amplitude of variation is almost the same as that under normal frequency mechanical ventilation.4 、 Compared to normal frequency mechanical ventilation mode, high frequency oscillatory ventilation mode has a smaller influence on haemodynamics and is safer; these two ventilation mode and different parameters of mechanical ventilation have different influence on the stability of hemodynamics.So we should monitor vascular Haemodynamicsindex continuouslyand in time.