| Background Prone position ventilation refers to assisting patients in prone position in the process of Mechanical ventilation, which is a therapeutic nursing interventions to improve oxygenation of patients. Prone position ventilation is mainly used in the treatment of acute respiratory distress syndrome and acute lung injury, but its application in patients with hypoxemia after cardiac surgery is rarely reported. Coronary artery bypass graft surgery is one of the main means of treatment of coronary heart disease. Postoperative hypoxemia is a common complication of coronary artery bypass grafting which has been affecting results of operations and attracting great clinical attention. At present, clinical monitoring in the hypoxemia after "off-pump" coronary artery bypass grafting includes four major areas, namely the maintenance of cardiac function, respiratory control, monitoring of bleeding and pain treatments. More attention is paid to the proper ventilation in respiratory control.Available conventional measures for improving the ventilation include increasing the concentration of inspired oxygen, suctioning properly, chest physiotherapy, lung recruitment, etc, but in some cases these methods are limited in effectiveness.Objective This study try to study effects of prone position ventilation on oxygenation level in patients with hypoxemia after off-pump coronary artery bypass grafting and to explore the feasibility and efficacy of prone position ventilation, so as to provide nursing guide and reference for hypoxemia after cardiac surgery.Methods Patients with hypoxemia after off-pump coronary artery bypass grafting were selected from September 2013 to August 2014 in a tertiary hospital cardiovascular surgery intensive care unit. Patients were divided into two groups according to conventional measures of intervention:control group (Group A), control group+ prone position ventilation group (Group B). Group A:General interventions include increasing inhalation oxygen concentration, chest physical treatment and lung dilated suction, etc. Improvement judgement standard is as follow:Artery blood oxygen points pressure (PaO2)/inhalation oxygen concentration (FiO2), namely oxygenation index increased over 20% after 24h. Group B:oxygenation index increased under 20% after 24h of general interventions, then prone position ventilation was used, life signs and the artery flesh analysis results were monitored and recorded before and 1h after prone position ventilation, 1h after recovery supine position.Improvement judgement standard is as follow:oxygenation index increased by more than 20% after prone position.SPSS 17.0 software was used to conduct statistical analysis. Measurement data were analyzed by t test, mean+ standard deviation. The two groups were compared with the independent samples t test, SNK-q test was used to compare multiple groups. Count data were compared using Chi-square test. P<0.05 was statistically significant.Results:1.Comparison of general information in two groupsThere were no significant differences (P>0.05) in gender, age, smoking, weight and coronary artery lesion and left ventricular ejection fraction, preoperative hypertension and diabetes duration of surgery and the number of grafts.2.Comparison of PaO2 and PaO2/FiO2 etc.after general interventionsAll selected 77 patients must monitor FiO2, PaO2, PaO2/FiO2, HR, SpO2, CVP, MAP and other indicators as a baseline before nursing intervention,PaO2/FiO2 increasement over 20% is oxygenation improvement standard 24h after conventional intervention. FiO2, PaO2, PaO2/FiO2, HR, SpO2, CVP, MAP and other indexes were compared in two groups:PaO2 (F=15.4854,P<0.0001), SpO2 (F=16.1659,P<0.0001), PaO2/FiO2 (F=22.0169,P<0.0001), CVP(F=15.8037,P<0.0001), were statistically significant (P<0.05), while there were no si gnificant differences (P>0.05) in HR (F=2.775,P=0.0654), MAP (F=0.5820, P=0.5600).3.Effects of prone position ventilation on respiratory mechanics of patients with moderate to severe hypoxemiaThe peak inflation pressure (Ppeak), mean airway pressure (Pmean) platform, airway pressure (Pplat) were compared before and 1h after prone position ventilation, 1h after recovery supine position. F value was 0.2237,1.5472 and 0.7381, P value was 0.7999, 0.2175 and 0.4804 respectively, there was no statistically significant difference between groups (P>0.05).4.Effects of prone position ventilation on hemodynamics of group B patientsHR, MAP and CVP were monitored before and lh after prone position ventilation, lh after recovery supine position.There was a significant difference (P<0.05) in HR (F=3.5655,P=0.0317) and CVP (F=4.1496,P=0.0184), while there was no significant difference in MAP (F=0.5620, and P= 0.5605).5.Comparision of oxygenation after implementation of prone position ventilation in Group B patientsSpO2, PaO2/FiO2 and PaO2 were compared before and 1h after recovery supine position, 1h after recovery supine position. F value was 27.9301,7.9463 and 6.3143,P value was is 0.0001,0.0006,0.0026, respectively, there are significant differences between the groups (P<0.05).6.Comparison of clinical outcomes between two groupsMechanical ventilation time, ICU length of stay, postoperative pulmonary infections, deaths, duct fall off and pressure sores were compared between two groups.Statistical results are as follow:there was significant difference (P< 0.05) in mechanical ventilation time (t=-10.062,P<0.0001), ICU length of stay (t=-6.803,P<0.0001), death (x2=3.9416, P=0.0471); there was no significant differences (P>0.05) in postoperative pulmonary infection (x2=0.6963,P=0.4040), duct fall off (x2=0.0047,P=0.9451) and pressure sores (x2= 0.2756,P=0.5996).ConclusionPatients with hypoxemia during mechanical ventilation after off-pump coronary artery bypass grafting were treated by conventional measures such as increasing the concentration of inspired oxygen, chest physiotherapy and lung dilated suction etc. But improvement is not obvious, Prone position ventilation can improve low oxygenation under close cooperation and intensive care of clinical team. |
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