This paper aims to propose a noninvasive radiotherapy patient positioning system based on structured light surface imaging, and evaluate its clinical feasibility. First, structured light sensors were used to obtain the panoramic point clouds during radiotherapy positioning in real time. The fusion of different point clouds and coordinate transformation were realized based on optical calibration and pose estimation, and the body surface was segmented referring to the preset region of interest (ROI). Then, the global-local registration of cross-source point cloud was achieved based on algorithms such as random sample consensus (RANSAC) and iterative closest point (ICP), to calculate 6 degrees of freedom (DoF) positioning deviation and provide guidance for the correction of couch shifts. The evaluation of the system was carried out based on a rigid adult phantom and volunteers’ body, which included positioning error, correlation analysis, and receiver operating characteristic (ROC) analysis. Using Cone Beam CT (CBCT) as the gold standard, the maximum translation and rotation errors of this system were (1.5 ± 0.9) mm along Vrt direction (chest) and (0.7 ± 0.3) ° along Pitch direction (head and neck). The Pearson correlation coefficient between results of system outputs and CBCT verification distributed in an interval of [0.80, 0.84]. Results of ROC analysis showed that the translational and rotational AUC values were 0.82 and 0.85, respectively. In the 4D freedom accuracy test on the human body of volunteers, the maximum translation and rotation errors were (2.6 ± 1.1) mm (Vrt direction, chest and abdomen) and (0.8 ± 0.4)° (Rtn direction, chest and abdomen) respectively. In summary, the positioning system based on structured light body surface imaging proposed in this article can ensure positioning accuracy without surface markers and additional doses, and is feasible for clinical application.
Objective To explore the effects of enteral tube feeding on moderate AECOPD patients who underwent noninvasive positive pressure ventilation ( NPPV) . Methods Sixty moderate AECOPD patients with NPPV admitted from January 2009 to April 2011 were recruited for the study. They were randomly divided into an enteral tube feeding group (n=30) received enteral tube feeding therapy, and an oral feeding group (n=30) received oral feeding therapy. Everyday nutrition intake and accumulative total nutrition intake in 7 days, plasma level of prealbumin and transferrin, success rate of weaning, duration of mechanical ventilation, length of ICU stay, rate of trachea cannula, and mortality rate in 28 days were compared between the two groups. Results Compared with the oral feeding group, the everyday nutrition intake and accumulative total nutrition intake in 7 days obviously increased (Plt;0.05) , while the plasma prealbumin [ ( 258.4 ±16.5) mg/L vs. (146.7±21.6) mg/L] and transferrin [ ( 2.8 ±0.6) g/L vs. ( 1.7 ±0.3) g/L] also increased significantly after 7 days in the enteral tube feeding group( Plt;0.05) . The success rate of weaning ( 83.3% vs. 70.0%) , the duration of mechanical ventilation [ 5. 6( 3. 2-8. 6) days vs. 8. 4( 4. 1-12. 3) days] , the length of ICU stay [ 9. 2( 7. 4-11. 8) days vs. 13. 6( 8.3-17. 2) days] , the rate of trachea cannula ( 16. 6% vs. 30. 0% ) , the mortality rate in 28 days ( 3. 3% vs. 10. 0% ) all had significant differences between the enteral tube feeding group and the oral feeding group. Conclusions For moderate AECOPD patients with NPPV, enteral tube feeding can obviously improve the condition of nutrition and increase the success rate of weaning, shorten the mechanical ventilation time and the mean stay in ICU, decrease the rate of trachea cannula and mortality rate in 28 days. Thus enteral tube feeding should be preferred for moderate AECOPD patients with NPPV.
Objective To investigate the effects of mask BiPAP noninvasive positive ventilation (NIPPV) during treadmill exercise on dyspnea index and exercise endurance in stable patients with severe chronic obstructive pulmonary disease (COPD). Methods Twenty inpatients with stable severe COPD between August 2015 and January 2016 were recruited in the study. The following parameters were measured before and after 8-week rehabilitation by NIPPV during treadmill exercises, including 12-minute walking distance (12MWD), Borg dyspnea score, mean pulmonary arterial pressure (mPAP), PaO 2 and PaCO 2, times of acute exacerbation in 1 year, adverse reactions, and adherence. Results After rehabilitation for 8 weeks, the following parameters were improved than those before treatment including 12MWD [(810±20) mvs. (680±15) m,P<0.01], Borg dyspnea score (2.4±0.1vs. 4.4±0.3,P<0.01), mPAP [(34.4±2.7) mm Hgvs. (43.5±3.8) mm Hg], PaCO 2 [(49.8±4.9) mm Hgvs. (64.3±5.2) mm Hg], PaO 2 [(64.4±4.1) mm Hgvs. (52.3±3.9) mm Hg] and the times of acute exacerbation (2.1±0.7vs. 4.3±2.1,P<0.01). Adverse reactions included oropharyngeal drying (2 cases) and gaseous distention (8 cases) which can be tolerated without special treatment. Conclusion Mask NIPPV during treadmill exercise is safe and effective for stable patients with severe COPD and worthy of clinical application.
Objective Sedation and/or analgesia is often applied during noninvasive positive pressure ventilation (NIPPV) to make patients comfortable, and thus improve the synchronization between patients and ventilator. Nevertheless, the effect of sedation and/or analgesia on the clinical outcome of the patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) after extubation remains controversial. Methods A retrospective study was conducted on patients with AECOPD who received NIPPV after extubation in seven intensive care units in West China Hospital, Sichuan University between December 2013 and December 2017 . A logistic regression model was used to analyze the association between the use of sedation and/or analgesia and clinical outcomes including rate of NIPPV failure (defined as the need for reintubation and mechanical ventilation), hospital mortality, and length of intensive care unit stay after extubation. Results A total of 193 patients were included in the analysis, and 62 cases of these patients received sedation and/or analgesia during NIPPV. The usage of sedation and/or analgesia could result in failure of NIPPV (adjusted odd ratio [OR] 0.10, 95% confidence interval [CI] 0.02 - 0.52, P=0.006) and death (adjusted OR=0.13, 95%CI 0.04 - 0.42, P=0.001). Additionally, intensive care unit stay after extubation was longer in the patients who did not receive sedation and/or analgesia than those who did (11.02 d vs. 6.10 d, P< 0.01). Conclusion The usage of sedation and/or analgesia during NIPPV can decrease both the rate of NIPPV failure and hospital mortality in AECOPD patients after extubation.
ObjectiveTo systematically review the effectiveness and safety of interventions which target to improve the rate of successful extubation in preterm infants.MethodsPubMed, Web of Science, Cochrane Library, Chongqing VIP database, China National Knowledge Infrastructure, and Wanfang Database were searched for articles published from the dates of establishment of databases to August 2020, which compared different noninvasive respiratory support models or different doses of caffeine to improve the rate of successful extubation in preterm infants in randomized controlled trials. The references of included articles were also retrieved. And then a meta-analysis was performed by using RevMan 5.3 software.ResultsA total of 33 randomized controlled trials involving 4 536 preterm infants were included. Compared with nasal continuous positive airway pressure (NCPAP), high-flow nasal cannula (HFNC) reduced the nose injury rate [odds ratio (OR)=0.29, 95% confidence interval (CI) (0.15, 0.57), P=0.000 3] and the pneumothorax rate [OR=0.18, 95%CI (0.06, 0.55), P=0.003]; nasal intermittent positive pressure ventilation (NIPPV) reduced the extubation failure rate [OR=0.33, 95%CI (0.23, 0.48), P<0.000 01], the reintubation rate [OR=0.36, 95%CI (0.20, 0.65), P=0.000 7], the respiratory failure rate [OR=0.33, 95%CI (0.17, 0.64), P=0.000 9], and the pneumothorax rate [OR=0.29, 95%CI (0.12, 0.70), P=0.006]; and biphasic positive airway pressure (BiPAP) reduced the reintubation rate [OR=0.21, 95%CI (0.09, 0.46), P=0.000 1]. Compared with low-dose caffeine, high-dose caffeine reduced the extubation failure rate [OR=0.44, 95%CI (0.32, 0.60), P<0.000 01] and the bronchopulmonary dysplasia rate [OR=0.69, 95%CI (0.48, 0.99), P=0.04], but increased the rate of tachycardia [OR=1.99, 95%CI (1.22, 3.25), P=0.006].ConclusionAccording to the current evidence, compared with NCPAP, NIPPV and BiPAP could be used to improve the rate of successful extubation in preterm infants, HFNC could be used to decrease the risk of nose injury and pneumothorax; the optimal dose of caffeine should be chosen after evaluating the risk of adverse reactions such as tachycardia.
Objective To investigate the safety of high fraction of inspired oxygen (FiO2)during noninvasive ventilation in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD)and carbon dioxide (CO2)retention. Methods Fifty-six AECOPD patients with CO2 retention admitted between March 2013 and August 2015 were recruited in the study.All patients received noninvasive ventilation treatment with FiO2<0.5.After stabilization of acute respiratory crisis,FiO2 was increased to 1.0 and lasted for 40 minutes.The changes of tidal volume,respiratory frequency,minute volume,Glasgow coma score,arterial blood gas and SpO2 were observed before and after the FiO2 reset. Results The mean PaO2 increased from (83±14)mm Hg to (165±41)mm Hg and the mean SpO2 increased from (92.4±3.1)% to (97.8±1.9)% significantly (both P<0.001).The mean PaCO2 did not changed obviously from (72±15)mm Hg to (72±14)mm Hg (P=0.438).There were also no significant changes in any of the other parameters. Conclusion During noninvasive ventilation with an FiO2 sufficient to maintain a normal PaO2,an increase in FiO2 does not further increase PaCO2 level in AECOPD patients with CO2 retention.
Objective To investigate the effects of different inspiratory rise time during noninvasive positive pressure ventilation ( NPPV) on work of breathing in patients with acute exacerbation of chronic obstructive pulmonary disease ( COPD) . Methods Eleven patients with acute exacerbation of COPD received different inspiratory rise time ( 0. 1sec, 0. 3sec, 0. 5sec) during NPPV. The changes of inspiratory muscle effort and breathing pattern of the patients were observed. Results The average respiratory rate,minute ventilation, and tidal volume were higher during NPPV compared with spontaneous breathing. But the changes of average minute ventilation and tidal volume were not significant ( P gt; 0. 05) . The pressure time product ( PTP) , transdiaphragmatic pressure ( Pdi) , and work of breathing of inspiratory muscle reduced significantly during different inspiratory rise time as compared with spontaneous breathing ( P lt;0. 01) . PTP,Pdi, and work of breathing reduced 59. 2% , 62. 7% , and 49% respectively when inspiratory rise time was 0. 1sec. They reduced more significantly during inspiratory rise time of 0. 1sec. Conclusions The present study confirms NPPV can unload inspiratory muscles in patients with acute exacerbation of COPD. It is more effective to reduce inspiratory load when inspiratory rise time is set at 0. 1sec while the patients feel most comfortable.
Most of the existing near-infrared noninvasive blood glucose detection models focus on the relationship between near-infrared absorbance and blood glucose concentration, but do not consider the impact of human physiological state on blood glucose concentration. In order to improve the performance of prediction model, particle swarm optimization (PSO) algorithm was used to train the structure paramters of back propagation (BP) neural network. Moreover, systolic blood pressure, pulse rate, body temperature and 1 550 nm absorbance were introduced as input variables of blood glucose concentration prediction model, and BP neural network was used as prediction model. In order to solve the problem that traditional BP neural network is easy to fall into local optimization, a hybrid model based on PSO-BP was introduced in this paper. The results showed that the prediction effect of PSO-BP model was better than that of traditional BP neural network. The prediction root mean square error and correlation coefficient of ten-fold cross-validation were 0.95 mmol/L and 0.74, respectively. The Clarke error grid analysis results showed that the proportion of model prediction results falling into region A was 84.39%, and the proportion falling into region B was 15.61%, which met the clinical requirements. The model can quickly measure the blood glucose concentration of the subject, and has relatively high accuracy.
ObjectiveTo evaluate the accuracy of the new dynamic approach in the measurement of respiratory mechanics with different pressure support (PS) level during pressure support ventilation (PSV) via oral-nasal mask.MethodsThe Respironics V60 ventilator was connected to a ASL5000 lung simulator, which simulate lung mechanics in patients with chronic obstructive pulmonary disease ［system compliance (Crs)=50 mL/cm H2O, airway resistance (Raw)=20 cm H2O/(L·s), inspiratory time (TI)=1.6 s, breathing rate=15 beats per minute］. PSV were applied with different levels of PS ［positive end-expiratory pressure=5 cm H2O, PS=5/10/15/20/25 cm H2O) and back-up rate=10 beats per minute］. Measurements were conducted at system leaks with 25 – 28 L/min. The performance characteristics and patient-ventilator asynchrony were assessed, including flow, airway pressure, time and workload. Crs and Raw were calculated by using new dynamic approach.ResultsTidal volume (VT) was increased with increasing PS level ［(281.45±4.26)mL at PS 5 cm H2O vs. (456.81±1.91)mL at PS 10 cm H2O vs. (747.45±3.22)mL at PS 20 cm H2O, P<0.01］. Severe asynchronous was occurred frequently when PS is at 25 cm H2O. Inspiration cycling criterion (CC) was up-regulated accompanied by increasing PS level ［(15.62±3.11)% at 5 cm H2O, vs. (24.50±0.77)% at 20 cm H2O, P<0.01］. Premature cycling was always existed during PSV when PS < 20 cm H2O, which could be eliminated as PS level increasing. Delay cycling was found when PS was at 20 cm H2O, and cycling delay time was (33.60±15.91)ms (P<0.01). The measurement of Crs was (46.19±1.57)mL/cm H2O with PS at 10 cm H2O, which was closer to the preset values of simulated lung. The underestimate of Crs was observed during high level PS support. The calculation of inspiratory and expiratory resistance was approximate to 20 cm H2O/(L·s) when PS level was exceeded 15 cm H2O.ConclusionsThe new dynamic approach can continuously assess the respiratory mechanics during non-invasive ventilation, which is no need to interrupt the patient's spontaneous breathing. Higher inspiratory flow during PSV is beneficial for Raw measurement, whereas the accuracy of Crs was influenced by the value of actual VT.
Objective To evaluate the efficiency and associated factors of noninvasive positive pressure ventilation( NPPV) in the treatment of acute lung injury( ALI) and acute respiratory distress syndrome( ARDS) .Methods Twenty-eight patients who fulfilled the criteria for ALI/ARDS were enrolled in the study. The patients were randomized to receive either noninvasive positive pressure ventilation( NPPV group) or oxygen therapy through a Venturi mask( control group) . All patients were closely observed and evaluated during observation period in order to determine if the patients meet the preset intubation criteria and the associated risk factors. Results The success rate in avoiding intubation in the NPPV group was 66. 7%( 10/15) , which was significantly lower than that in the control group ( 33. 3% vs. 86. 4% , P = 0. 009) . However, there was no significant difference in the mortality between two groups( 7. 7% vs.27. 3% , P =0. 300) . The incidence rates of pulmonary bacteria infection and multiple organ damage were significantly lower in the NPPV success subgroup as compared with the NPPV failure group( 2 /10 vs. 4/5, P =0. 01;1 /10 vs. 3/5, P = 0. 03) . Correlation analysis showed that failure of NPPV was significantly associated with pulmonary bacterial infection and multiple organ damage( r=0. 58, P lt;0. 05; r =0. 53, P lt;0. 05) . Logistic stepwise regression analysis showed that pulmonary bacterial infection was an independent risk factor associated with failure of NPPV( r2 =0. 33, P =0. 024) . In the success subgroup, respiratory rate significantly decreased( 29 ±4 breaths /min vs. 33 ±5 breaths /min, P lt; 0. 05) and PaO2 /FiO2 significantly increased ( 191 ±63 mmHg vs. 147 ±55 mmHg, P lt;0. 05) at the time of 24 hours after NPPV treatment as compared with baseline. There were no significant change after NPPV treatment in heart rate, APACHEⅡ score, pH and PaCO2 ( all P gt;0. 05) . On the other hand in the failure subgroup, after 24 hours NPPV treatment, respiratory rate significantly increased( 40 ±3 breaths /min vs. 33 ±3 breaths /min, P lt;0. 05) and PaO2 /FiO2 showed a tendency to decline( 98 ±16 mmHg vs. 123 ±34 mmHg, P gt; 0. 05) . Conclusions In selected patients, NPPV is an effective and safe intervention for ALI/ARDS with improvement of pulmonary oxygenation and decrease of intubation rate. The results of current study support the use of NPPV in ALI/ARDS as the firstline choice of early intervention with mechanical ventilation.