The setting and adjustment of ventilator parameters need to rely on a large amount of clinical data and rich experience. This paper explored the problem of difficult decision-making of ventilator parameters due to the time-varying and sudden changes of clinical patient’s state, and proposed an expert knowledge-based strategies for ventilator parameter setting and stepless adaptive adjustment based on fuzzy control rule and neural network. Based on the method and the real-time physiological state of clinical patients, we generated a mechanical ventilation decision-making solution set with continuity and smoothness, and automatically provided explicit parameter adjustment suggestions to medical personnel. This method can solve the problems of low control precision and poor dynamic quality of the ventilator’s stepwise adjustment, handle multi-input control decision problems more rationally, and improve ventilation comfort for patients.
Objective To analyze the causes of missed diagnosis of sleep apnea hypopnea syndrome ( SAHS) . Methods 42 missed diagnosed cases with SAHS from May 2009 to May 2011 were retrospectively analyzed and related literatures were reviewed. Results The SAHS patients often visited the doctors for complications of SAHS such as hypertension, diabetes mellitus, metabolic syndrome, etc. Clinical misdiagnosis rate was very high. Lack of specific symptoms during the day, complicated morbidities, and insufficient knowledge of SAHS led to the high misdiagnosis rate and the poor treatment effect of patients with SAHS. Conclusion Strengthening the educational propaganda of SAHS, detail medical history collection, and polysomnography monitoring ( PSG) as early as possible can help diagnose SAHS more accurately and reduce missed diagnosis.
ObjectiveTo evaluate the superiority of nasopharyngeal airway on obesity patients during general anesthesia induction period. MethodForty-two trachea cannula and general anesthesia obesity patients treated from June to November in 2013 were chosen and divided equally into two groups:nasopharyngeal airway group (group A) and control group (group B). Mean arterial pressure (MAP), heart rate (HR), pulse oxygen saturation (SpO2), arterial blood partial pressure of carbon dioxide (PaCO2) were recorded when the patients entered the operation room, three minutes after man-made positive pressure ventilating and five minutes after intubation. Peak voltage (Ppeak) of man-made positive pressure ventilation for three minutes was also observed, and intubation frequency and time, mouth mucosa bleeding, and sore throat examples were compared between the two groups. ResultsCompared with group B, MAP, HR, PaCO2 and Ppeak three minutes after man-made positive pressure ventilating were lower (P<0.05), but SpO2 was higher in group A (P<0.05). Intubation frequency and time, mouth mucosa bleeding, and sore throat examples of group A were less than those in group B (P<0.05). ConclusionsNasopharyngeal airway is better for obesity patients during general anesthesia induction period, which also improves anesthesia safety level.
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 evaluate the effects of midazolam intravenous drip combined with lidocaine via nebulization on patients during mechanical ventilation in intensive care unit ( ICU) . Methods 60 thoracic patients required postoperative mechanical ventilation in ICUwere randomized into 2 groups. The patients in therapeutic group received lidocaine 1 mg/kg via nebulization and midazolam intravenous drip 0. 1 mg·kg- 1·h- 1 . The patients in control group received 0. 9% NaCl 1 mg/kg via nebulization andmidazolam0. 1 mg·kg- 1 ·h- 1 . According to the scale of Ramsay, the additional midazolam and fentanyl were injected to maintain sedation and inhibit cough in both groups. During ventilation, calm score, the number and the severity of cough, the mean arterial pressure ( MAP) , heart rate ( HR) , and the consumption of midazolam and fentanyl were record. Results The number and severity of cough, the scale of MAP and HR in the therapeutic group were all significant lower than those in the control group ( P lt; 0. 05) . Theconsumption of midazolam and fentanyl in the therapeutic group were also significantly lower than that in the control group ( P lt; 0. 05) .Conclusion Midazolam intravenous drip combined with lidocaine via nebulization can reduce the side effects and requirement of sedative and opioids drug in ICU patients undergoing mechanical ventilation.
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 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.
In the clinical practice, the mechanical ventilation is a very important assisting method to improve the patients' breath. Whether or not the parameters set for the ventilator are correct would affect the pulmonary gas exchange. In this study, we try to build an advisory system based on the gas exchange model for mechanical ventilation using fuzzy logic. The gas exchange mathematic model can simulate the individual patient's pulmonary gas exchange, and can help doctors to learn the patient's exact situation. With the fuzzy logic algorithm, the system can generate ventilator settings respond to individual patient, and provide advice to the doctors. It was evaluated in 10 intensive care patient cases, with mathematic models fitted to the retrospective data and then used to simulate patient response to changes in therapy. Compared to the ventilator set only as part of routine clinical care, the present system could reduce the inspired oxygen fraction, reduce the respiratory work, and improve gas exchange with the model simulated outcome.
Objective To analysis the risk factors for lower airway bacteria colonization and ventilator-associated pneumonia ( VAP) in mechanically ventilated patients. Methods A prospective observational cohort study was conducted in intensive care unit. 78 adult inpatients who underwent mechanical ventilation( MV) through oral endotracheal intubation between June 2007 and May 2010 were recruited. Samples were obtained from tracheobronchial tree immediately after admission to ICU and endotracheal intubation( ETI) , and afterward twice weekly. The patients were divided naturally into three groups according to airway bacterial colonization. Their baseline characteristics, APACHEⅡ score, intubation status and therapeutic interventions, etc. were recorded and analyzed. Results In the total 78 ventilated patients, the incidence of lower airway colonization and VAP was 83. 3% and 23. 1% , respectively. The plasma albumin( ALB) ≤29. 6 g/L( P lt; 0. 05) , intubation attempts gt; 1( P lt; 0. 01) were risk factors for lower airway colonization. In the patients with lower airway colonization, preventive antibiotic treatment, applying glucocorticoid and prealbumin( PA) ≤ 69. 7 mg/L were risk factors for VAP ( P lt; 0. 05) . Conclusions The risk factors for lower airway colonization in ventilated patients were ALB≤29. 6 g/L and intubation attempts gt; 1. And for lower airway colonized patients, PA ≤ 69. 7 mg/L, preventive antibiotic treatment and applying glucocorticoid were risk factors for VAP.