Objective To compare the humidification effect of the MR410 humidification system and MR850 humidification system in the process of mechanical ventilation. Methods Sixty-nine patients underwent mechanical ventilation were recruited and randomly assigned to a MR850 group and a MR410 group. The temperature and relative humidity at sites where tracheal intubation or incision, the absolute humidity, the sticky degree of sputum in initial three days after admission were measured. Meanwhile the number of ventilator alarms related to sputum clogging and pipeline water, incidence of ventilator associated pneumonia, duration of mechanical ventilation, and mortality were recorded. Results In the MR850 group,the temperature of inhaled gas was ( 36. 97 ±1. 57) ℃, relative humidity was ( 98. 35 ±1. 32) % , absolute humidity was ( 43. 66 ±1. 15) mg H2O/L, which were more closer to the optimal inhaled gas for human body.The MR850 humidification system was superior to the MR410 humidification system with thinner airway secretions, less pipeline water, fewer ventilator alarms, and shorter duration of mechanical ventilation. There was no significant difference in mortality between two groups. Conclusions Compared with MR410 humidification system, MR850 humidification system is more able to provide better artificial airway humidification and better clinical effect.
Objectives To assess the prognostic value of blood sugar level for acute respiratory failure patients undergoing mechanical ventilation. Methods The study collected 139 acute respiratory failure patients undergoing mechanical ventilation admitted between February 2012 and October 2013. The patients were divided into a hyperglycemic group (n=123, blood sugar ≥143 mg/dl) and a non-hyperglycemic group (n=16, blood sugar <143 mg/dl). The data for basic clinical pathological characteristics and the blood sugar levels were collected, and the correlation between the blood sugar level and the prognosis was assessed using single factor analysis and logistic regression method. Results In the study, 88.49% of patients with acute respiratory failure undergoing mechanical ventilation had hyperglycemia (blood sugar ≥143 mg/dl). The proportions of patients with APACHEⅡ score ≥10, chronic obstructive pulmonary disease (COPD) or hypoxemia in the hyperglycemic group were significantly higher than those in the non-hyperglycemic group (P<0.05). APACHEⅡ ≥10, COPD and hypoxemia were significant risk factors for hyperglycemia. At the same time, the proportions of patients in the death group with hyperglycemia ≥143 mg/dl ( OR=8.354, 95%CI 1.067-65.388, P=0.018), APACHEⅡ≥10 ( OR=2.545, 95%CI 1.109-6.356, P=0.046), COPD ( OR=2.871, 95%CI 1.203-6.852, P=0.015), and hypoxemia ( OR=3.500, 95%CI 1.556-7.874, P=0.002) were significantly higher than those in the survival group. Kaplan-Meier curve analysis found that the overall survival of the hyperglycemic patients with acute respiratory failure was significantly lower than that in the non-hyperglycemic patients (P<0.001). Conclusion Blood sugar level can be used as an independent predictor for acute respiratory failure patients undergoing mechanical ventilation.
Objective To determine the usefulness of serial measurements of the rapid shallow breathing index ( f/VT , RSBI) as a predictor for successfully weaning of patients undergoing prolonged mechanical ventilation ( gt; 72 hours) . Methods 76 mechanically ventilated patients were prospectively analyzed. 120-min spontaneous breathing trial was conducted after the patients having fullfiled the traditional weaning criteria, and RSBI were continuously monitored by the ventilator at five time points ( 5, 15, 30,60, and 120 min) . A repeated measure of general linear model in SPSS 15.0 was conducted to analyze the data. Results 62 patients completed 120-minute spontaneous breath trial and in which 20 patients failed weaning. There was no significant difference of RSBI at five time points during weaning ( P gt;0. 05) . But thevariation trends of RSBI during weaning time were significant different between the successful weaning patients and the failed weaning patients ( P lt; 0. 05) . Conclusions In patients undergoing prolonged mechanical ventilation, the variation trend of RSBI is more valuable than single RSBI in the prediction ofsuccessful weaning.
Objective To analyze the risk factors for duration of mechanical ventilation in critically ill patients. Methods Ninety-six patients who received mechanical ventilation from January 2011 to December 2011 in intensive care unit were recruited in the study. The clinical data were collected retrospectively including the general condition, underlying diseases, vital signs before ventilation, laboratory examination, and APACHEⅡ score of the patients, etc. According to ventilation time, the patients were divided into a long-term group ( n = 41) and a short-term group ( n = 55) . Risk factors were screened by univariate analysis, then analyzed by logistic regression method.Results Univariate analysis revealed that the differences of temperature, respiratory index, PaCO2 , white blood cell count ( WBC) , plasma albumin ( ALB) , blood urea nitrogen ( BUN) , pulmonary artery wedge pressure ( PAWP) , APACHEⅡ, sex, lung infection in X-ray, abdominal distention, and complications between two groups were significant.With logistic multiple regression analysis, the lower level of ALB, higher level of PAWP, lung infection in X-ray, APACHE Ⅱ score, abdominal distention, and complications were independent predictors of long-term mechanical ventilation ( P lt;0. 05) . Conclusion Early improving the nutritional status and cardiac function, control infection effectively, keep stool patency, and avoid complications may shorten the duration of mechanical ventilation in critically ill patients.
Objective To study the effects of two different tidal volume mechanical ventilation on lipopolysaccharide( LPS) -induced acute lung injury( ALI) , and explore the effects of glutamine on ALI.Methods Thirty male Sprague-Dawley rats were randomly divided into three groups. After anesthesia and tracheotomy were performed, the rats were challenged with intratracheal LPS ( 5mg/kg) and received ventilation for 4 hours with small animal ventilator. Group A received conventional tidal volume, while groupB received large tidal volume. Group C received large tidal volume as well, with glutamine injected intravenously 1 hour before ventilation. Arterial blood gases were measured every one hour. 4 hours later, the rats were killed by carotid artery bleeding. The total lung wetweightwas measured and lung coefficient ( total lung wet weight /body weight ×100) was counted. WBCs and neutrophils in BALF were counted. Protein concentration, TNF-α, IL-6, and cytokine-induced neutrophil chemoattractant-1 ( CINC-1) levels in BALF,myeloperoxidase ( MPO) , and superoxide dismutase ( SOD) levels in the lung were assayed respectively.Results PaO2 and SOD levels decreased more significantly in group B than those of group A. The lung coefficient, WBCs, neutrophils, protein, TNF-α, IL-6, and CINC-1 levels in BALF, MPO levels in lung increased more significantly in group B than those of group A. PaO2 and SOD levels were significantly higher in group C than those of group B. The lung coefficient, WBCs, neutrophils, protein, TNF-α, IL-6, and CINC-1 levels in BALF,MPO levels in lung were significantly lower in group C than those of group B. Conclusion Large tidal volume mechanical ventilation aggravates LPS-induced ALI, and glutamine has obviouslyprotective effects.
Objective To evaluate the influence of tidal volume on the accuracy of stroke volume variation ( SVV) to predict volume state of pigs with ventilation.Methods Thirty-six healthy pigs were anesthetized after tracheal intubation and ventilated. With the envelope method, they were randomized into a normovolemia group, a hemaerrhagic shock group, and a hypervolemia group, with 12 pigs in each group. The pigs in the hemaerrhagic shock group were removed 20 percent of blood, and the pigs in the hypervolemia group received additional infusion of 20 percent 6% hydroxyethyl starch. In each group, ventilator settings were changed in a randomized order by changing VT [ VT = 5 mL/kg ( VT5 ) , VT =10 mL/kg ( VT10 ) , and VT =15 mL/kg ( VT15 ) ] . Hemodynamic measurements [ heart rate ( HR) , mean arterial boold pressure ( MAP) , systemic vascular resistance index ( SVRI) , cardiac index ( CI) , stroke volume index ( SVI) , intrathoracic blood volume index( ITBVI) , and SVV] were obtained after 10 minutes of stabilization. Results SVV was increased in the hemaerrhagic shock group comparing with the normovolemia group for VT10 [ ( 21 ±5) % vs. ( 11 ±2) % , P lt;0. 05] , but SVV was decreased in the hypervolemia group comparing with the normovolemia group [ ( 7 ±2) % vs. ( 11 ±2) % , P lt; 0. 05] . The variation tendency for VT15 was the same with VT10 , moreover SVV were all above 12% for the hemaerrhagic shock group, the normovolemia group, and the hypervolemia group [ ( 30 ±7) % , ( 19 ±3) % , and ( 15 ±4) % ] . There were no significant diffrences among the hemaerrhagic shock group, hypervolemia group and normovolemia group [ ( 8 ±6) % ,( 7 ±5) % , and ( 7 ±4) % , P gt; 0. 05] for VT5 . Conclusions SVV was a precise indicator of cardiac preload, but SVV was less sensitive to the changes of volume during low tidal volume ( 5 mL/kg) ventilation. The threshold of SVV for predicting fluid responsiveness maybe above 12% with a high tidal volume ( 15 mL/kg) ventilation.
Objective To establish a rabbit model of ventilator-induced lung injury. Methods Fourty healthy New Zealand rabbits were randomly divided into 3 groups: ie. a routine 8 mL/kg tidal volume group( VT8 group) , 25 mL/kg large tidal volume group( VT25 group) , and 40 mL/kg large tidal volume group( VT40 group) . VT25 and VT40 group were further divided into 2 hours and 4 hours ventilation subgroups. Arterial blood gas, lung mechanical force and hemodynamic parameters were monitored. Lungtissue was sampled for evaluate lung wet/dry ratio and lung injury by HE stain. Bronchoalveolar lavage fluid ( BALF) was collected for measurement of protein concentration, total and differential cell counts. Results Compared with VT8 group, lung injury score in both VT40 and VT25 groups were elevated significantly, ofwhich 4 hour VT40 subgroup was the highest. Lung pathology examination of VT40 group revealed apparent alveolar deformation, interstitial and alveolar space exudation, inflammatory cells infiltration, pulmonary consolidation and alveolar hemorrhage. Lung pathology examination of VT25 group showed pulmonary intervalthickening, inflammatory cells infiltration, while alveolar intravasation was mild. Blood gas analysis showed that PaO2 /FiO2 was deteriorated with time in VT25 and VT40 groups, and PaO2 /FiO2 at the 3 hours in VT40 group( lt; 300 mm Hg) had met the acute lung injury standard, while which in VVT25 group was above 300 mmHg. Lung wet/dry ratio, BALF protein concentration, total nucleated cell and neutrophilic leukocyte were elevated in both VT25 and VT40 groups, of which 4 hours VT40 group was the highest. Conclusion Using 4 hours ventilation at a tidal volume of 40 mL/kg can successfully establish the rabbit model of ventilator-induced lung injury.
Objective To compare the diagnostic value of sterile sputumsuction tube with protected specimen brush in mechanically ventilated patients with serious lung infection, and explore the safety and efficacy of bronchofibroscope combining mechanical ventilation in the treatment of severe lung infection.Methods Seventy-four severe lung infection patients with invasive mechanical ventilation support were recruited in the study. Based on the routine treatment, the subjects were randomly divided into a control group received only mechanical ventilation, and a treatment group received sputum aspiration and bronchial lavage by bronchofibroscope combiningmechanical ventilation. Lower respiratory tract secretion was collected to analyze the bacterial etiology with sterile sputum suction tube in the control group, and with protectedspecimen brush in the treatment group. Results The positive rate of sputum suction tube and protected specimen brush was 70. 27% and 75. 68% , respectively, with no statistical difference between the two groups ( P gt; 0. 05) . The PaO2 of the treatment group increased and PaCO2 decreased obviously after sputum aspiration and bronchial lavage by bronchofibroscope ( P lt; 0. 01) . The total effective rate was also highly increased, and the heart rate and respiration were stable in the treatment group. The time of mechanical ventilation and the length of ICU stay were all shortened in the treatment group compared with the control group. Conclusions Sterile sputum suction tube can not only acquire accurate pathogen, but also is a simple and economical method for patients with severe lung infection with mechanical ventilation. Sputum aspiration and bronchial lavage with bronchofibroscope combining mechanical ventilation are effective and safe treatment for patients with severe lung infection.
Objective To observe the effects of peritoneal ventilation with pure oxygen in the rabbits with hypoxaemia and hypercapnia induced by mechanical controlled hypoventilation. Methods Sixteen rabbits were invasively ventilated after trachea incision. Hypoxaemia and hypercapnia were induced by hypoventilation which was implemented both by degrading ventilation parameters and respiratory depression induced by intravenous infusion of muscle relaxant. Then pure oxygen was insufflated into the peritoneal cavity and arterial blood gases were measured every 30 minutes for two hours. Results The PaO2 was ( 52. 50 ±3. 46) mmHg at baseline and increased to ( 76. 46 ±7. 79) mm Hg, ( 79. 62 ±9. 53) mm Hg,( 78. 54 ±7. 18) mmHg, and ( 81. 1 ±8. 3) mm Hg, respectively at 30, 60, 90, and 120 minutes after the peritoneal ventilation with pure oxgen( all P lt; 0. 05) . Meanwhile PaCO2 was ( 63. 84 ±9. 09) mm Hg at baseline and ( 59. 84 ±14. 22) mmHg, ( 59. 16 ±15. 5) mmHg, ( 60. 02 ±7. 07) mmHg, and ( 61. 38 ±6. 56) mm Hg, respectively at 30, 60, 90, and 120 minutes after the peritoneal ventilation with pure oxgen with no significant change( P gt;0. 05) . Conclusion Peritoneal ventilation can obviously improve hypoxaemia induced by mechanical controlled hypoventilation, whereas hypercapnia remains unchanged.
Objective To analyze the common causes of ventilator alarms during mechanical ventilation and their management. Methods A total of 104 ventilator alarms that were not instantly solved by first-line residents but referred to pulmonary therapist and attending physicians during September 2007 and August 2008 in the MICU of our hospital were analyzed retrospectively. Results Of all the 104 ventilator alarms, 27 ( 26%) were due to problems of ventilation circuits; 18 were due to patient effortagainst ventilator secondary to anxiety, horror or pain; 15 were due to inappropriate ventilator parameters;13 were due to airway problems; 5 were due to ventilator malfunction; 4 were due to worsening clinical status; 22 were due to other causes. Conclusion During mechanical ventilation, accurate assessment andprompt management of ventilator alarms are of great importance to patient safety and ventilation efficacy.