Design of Portable Noninvasive Positive Pressure Ventilator System Based on Threshold Trigger of Flow Rate Change / 中国医疗器械杂志

In order to effectively treat respiratory diseases, a non-invasive positive pressure ventilator system is designed, the overall structure design of the system is proposed, and the hardware construction is completed. The breathing state of the patient is identified by the threshold triggering method of the flow rate of change, and the calculation of the flow rate of change is realized by the least squares method. At the same time, the breathing parameters are calculated in real time according to the flow-time and pressure-time characteristic curves. In addition, CMV, CPAP, BiPAP and PSV ventilation modes are also implemented. Finally, the parameter measurement accuracy and ventilation mode setting tests are carried out. The results show that the calculation of key breathing parameters provided by the system meets the relevant standards, and supports the stable output of 4 ventilation modes at the same time, provides breathing treatment for patients, and meets the basic functional requirements of the ventilator.

Therapeutic efficacy of volume-guaranteed high frequency oscillation ventilation on respiratory failure in preterm infants with a gestational age of 28-34 weeks: a prospective randomized controlled study / 中国当代儿科杂志

OBJECTIVES@#To investigate the therapeutic efficacy of volume-guaranteed high frequency oscillation ventilation (HFOV-VG) versus conventional mechanical ventilation (CMV) in the treatment of preterm infants with respiratory failure.@*METHODS@#A prospective study was conducted on 112 preterm infants with respiratory failure (a gestational age of 28-34 weeks) who were admitted to the Department of Neonatology, Jiangyin Hospital Affiliated to Medical School of Southeast University, from October 2018 to December 2022. The infants were randomly divided into an HFOV-VG group (44 infants) and a CMV group (68 infants) using the coin tossing method based on the mode of mechanical ventilation. The therapeutic efficacy was compared between the two groups.@*RESULTS@#After 24 hours of treatment, both the HFOV-VG and CMV groups showed significant improvements in arterial blood pH, partial pressure of oxygen, partial pressure of carbon dioxide, and partial pressure of oxygen/fractional concentration of inspired oxygen ratio (P<0.05), and the HFOV-VG group had better improvements than the CMV group (P<0.05). There were no significant differences between the two groups in the incidence rate of complications, 28-day mortality rate, and length of hospital stay (P>0.05), but the HFOV-VG group had a significantly shorter duration of invasive mechanical ventilation than the CMV group (P<0.05). The follow-up at the corrected age of 6 months showed that there were no significant differences between the two groups in the scores of developmental quotient, gross motor function, fine motor function, adaptive ability, language, and social behavior in the Pediatric Neuropsychological Development Scale (P>0.05).@*CONCLUSIONS@#Compared with CMV mode, HFOV-VG mode improves partial pressure of oxygen and promotes carbon dioxide elimination, thereby enhancing oxygenation and shortening the duration of mechanical ventilation in preterm infants with respiratory failure, while it has no significant impact on short-term neurobehavioral development in these infants.

Effect of ventilation mode on pulmonary complications after thoracoscopic lung resection: A retrospective cohort study / 中国胸心血管外科临床杂志

@#Objective     To evaluate the association between pressure-controlled ventilation-volume guaranteed (PCV-VG) mode and volume-controlled ventilation (VCV) mode on postoperative pulmonary complications (PPCs) in patients undergoing thoracoscopic lung resection. Methods     A retrospective cohort analysis of 329 patients undergoing elective thoracoscopic lung resection in West China Hospital of Sichuan University between September 2020 and March 2021 was conducted, including 213 females and 116 males, aged 53.6±11.3 years. American Society of Anesthesiologists (ASA) grade wasⅠ-Ⅲ. The patients who received lung-protective ventilation strategy during anesthesia were divided into a PCV-VG group (n=165) and a VCV group (n=164) according to intraoperative ventilation mode. Primary outcome was the incidence of PPCs during hospitalization. Results     A total of 73 (22.2%) patients developed PPCs during hospitalization. The PPCs incidence of PCV-VG and VCV was 21.8% and 22.6%, respectively (RR=0.985, 95%CI 0.569-1.611, P=0.871). Multivariate logistic regression analysis showed that there was no statistical difference in the incidence of PPCs between PCV-VG and VCV mode during hospitalization (OR=0.846, 95%CI 0.487-1.470, P=0.553). Conclusion     Among patients undergoing thoracoscopic lung resection, intraoperative ventilation mode (PCV-VG or VCV) is not associated with the risk of PPCs during hospitalization.

Modos ventilatorios usados en pacientes críticos con covid-19 en la región de Lombardía, Italia / Ventilation modes used in critical patient with COVID-19 in the region of Lombardy, Italy

RESUMEN Introducción: la covid-19 es una enfermedad donde la ventilación mecánica artificial cobra vital importancia. Se estima que el 50 % de los casos graves o críticos que requieren manejo en unidades de cuidados intensivos fallecen. Objetivos: se evaluó el impacto de los modos ventilatorios usados en pacientes con covid-19 en Lombardía, Italia, en la oxigenación, la hemodinámica y la mortalidad. Materiales y métodos: se realizó un estudio analítico longitudinal retrospectivo en 86 pacientes críticos con covid-19, en el Hospital Mayor de Crema, en Lombardía, Italia, desde el 1 de abril al 20 de mayo de 2020. Se realizaron análisis no paramétrico y de la varianza. Resultados: Hubo una supervivencia del 76,7 %. El modo utilizado tuvo igual comportamiento en occisos (BiPAP-3, PCV-4, VCRP-4, APRV-5, VCV-4) y en vivos (BiPAP-10, PCV-17, VCRP-14, APRV-15, VCV-10); test de x2 = 0,59; test de análisis de la varianza media índice PO2/FIO2 (PCV = 132), (BiPAP = 132) (VCV = 115) p = 0,924. La presión de final de espiración positiva (BiPAP-12, PCV-13, VCRP-13, APRV-13, VCV-14) con p = 0,205. PCO2 (BiPAP-55, PCV-52, VCRP-57, APRV-59, VCV-57) con p = 0,512. La tensión arterial media (BiPAP-84, PCV-83, VCRP-84, APRV-82, VCV-83) con p = 0,988. Modelos de cálculo de la presión de final de espiración positiva, según modo ventilatorio: BiPAP: PEEP = -0,0331 (índice PO2/FiO2) +18,215; PCV: PEEP = -0,0047 (índice PO2/FiO2) +13,717; VCRP: PEEP = -0,0204 (índice PO2/FiO2) +15,678; APRV: PEEP = -0,0092 (índice PO2/FiO2) +14,889. Conclusiones: la evolución del paciente crítico con covid-19 está determinada en gran medida por la ventilación mecánica invasiva; sin embargo, no existió suficiente evidencia para recomendar una u otra modalidad ventilatoria. El éxito está en conocer con exactitud las características del respirador, su modalidad y el paciente en cuestión. (AU)

ABSTRACT Introduction: COVID-19 is a disease in which mechanical ventilation acquires vital importance. It is estimated that 50 % of the serious and critical patients requiring management in intensive care units die. Objectives: to assess the impact of the ventilation modes used in patients with COVID-19 in Lombardy, Italy, on oxygenation, hemodynamics and mortality. Materials and methods: a retrospective, longitudinal, analytic study was carried out in 86 critical patients with COVID-19 who entered the Main Hospital of Crema, in Lombardy, Italy, from April 1st to May 20, 2020. Results: the survival was 76.7 %. The used mode showed the same behavior in deceased patients (BiPAP-3, PCV-4, VCRP-4, APRV-5, VCV-4) and in alive patients (BiPAP-10, PCV-17, VCRP-14, APRV-15, VCV-10). X2 = 0.59. ANOVA test index PO2/FIO2 (PCV = 132), (BiPAP = 132) (VCV=115) p = 0.924. PEEP (BiPAP-12, PCV-13, VCRP-13, APRV-13, VCV-14) p = 0.205. PCO2 (BiPAP-55, PCV-52, VCRP-57, APRV-59, VCV-57) p = 0.512. Average blood pressure (BiPAP-84, PCV-83, VCRP-84, APRV-82, VCV-83) p = 0.988. PEEP models according to ventilation mode: BiPAP: PEEP = -0.0331 (PO2/FiO2 index) +18.215. PCV: PEEP = -0.0047 (PO2/FiO2 index) + 13.717; VCRP: PEEP = -0.0204 (PO2/FiO2 index) + 15.678; APRV: PEEP = -0.0092 (PO2/FiO2 index) +14.889. Conclusion: the evolution of the critical patient with COVID-19 is determined mostly by the invasive mechanical ventilation; but we did not find evidence enough to recommend one or the other ventilation mode. The success stands in knowing accurately the characteristics of the ventilator, the ventilation modes and the patient (AU).

Development Progress of Ventilator / 中国医疗器械杂志

Ventilator is an indispensable emergency medical equipment in hospitals. The global outbreak of the coronavirus disease 2019 (COVID-19) has highlighted the importance of the ventilator, which has attracted the attention and research on ventilators of all countries in the world. This article reviews the development history of the ventilator, briefly introduces the main air circuit structure and working principle of the ventilator, and then deeply analyzes the key technologies of this device. In addition, it compares some major brands of ventilators from several aspects in the market. Finally, the development trend and perspective of ventilators are presented.

Prospects and developments in the technologies of high frequency oscillatory ventilation / 生物医学工程学杂志

The high frequency oscillatory ventilation (HFOV) is characterized with low tidal volume and low mean airway pressure, and can well support the breathing of the patients with respiratory diseases. Since the HFOV was proposed, it has been widely concerned by medical and scientific researchers. About the HFOV, this paper discussed its current research status and prospected its future development in technologies. The research status of ventilation model, mechanisms and ventilation mode were introduced in detail. In the next years, the technologies in developing HFOV will be focused on: to develop the branched high-order nonlinear or volume-depended resistance-inertance-compliance (RIC) ventilation model, to fully understand the mechanisms of HFOV and to achieve the noninvasive HFOV. The development in technologies of HFOV will be beneficial to the patients with respiratory diseases who failed with conventional mechanical ventilation as one of considerable ventilation methods.

Questionnaires analysis on present status of ventilation therapy in cardiopulmonary resuscitation in Chinese emergency physicians / 中国中西医结合急救杂志

Objective To investigate the current practice of ventilation during cardiopulmonary resuscitation (CPR) in Chinese emergency physicians. Methods Self-designed questionnaires were used to survey mainly the present situation of CPR ventilation practice performed by 800 physicians who participated in the Peking Union International Summit for Emergency Medicine from April 17th to 19th, 2015. Results A total of 800 questionnaires were distributed and 638 (79.75%) valid questionnaires were taken back; the responders joining the survey came from 29 provinces and regions, including Beijing, Hebei, Shandong, Guangdong, Liaoning, etc. There were 331 males and 307 females; 91.54% (584 responders) were emergency physicians and 77.90% (497 responders) came from tertiary hospitals, 17.55% (112 responders) came from the secondary hospitals. Regarding ventilation during CPR, 86.4% (551 responders) declared the patients was routinely given endo-tracheal intubation; after intubation, 25.8% (142 responders) adopted bag-mask ventilation, and 74.2% (409 responders) applied mechanical ventilation. When a ventilator was used, 301 (73.6%) responders used the volume controlled ventilation mode, 334 (81.7%) responders set the respiratory rate (RR) lower than 15 bpm, while 89.2% (365 responders) used the tidal volume set at a range of 400-500 mL. When adopted the flow triggering sensitivity, 79.7% (326 responders) set the sensitivity at 1-6 L/min, while 16.4% (67 responders) selected the default parameter, not adjusting the flow triggering parameter; when adopted the pressure triggering sensitivity, 75.1% (307 responders) set the sensitivity between -1 to -6 cmH2O (1 cmH2O = 0.098 kPa) and 20.3% (83 responders) selected the default value, not adjusting the pressure triggering parameter. When the mechanical ventilation (MV) was adopted, 84.8% (347 responders) declared often experiencing problems with MV, such as airway high peak pressure alarms [39.6% (162/409)], lower ventilation volume per minute alarms [24.9% (102/409)], higher respiratory frequency alarms [21.3% (87/409)], but only 67.2% (275 responders) would again adjust the ventilation mode related parameters and only 59.2% (242 responders) would observe the actual respiratory frequency. Conclusions With regards to artificial ventilation during CPR, the majority of emergency physicians tend to adopt endotracheal intubation and commonly use the volume controlled mode of mechanical ventilation; among the ventilator parameter setting, the RR is not strictly in accordance with the CPR guidelines, and most of the inspiration triggering sensitivity setting was too low, very easily to induce hyperventilation; simultaneously, the emergency physicians often neglect the practical RR; although there are many problems with ventilation such as frequent alarms, only 67.2% of the emergency physicians would again adjust the ventilation parameters.

A analysis on the effect of PRVC mode of ventilator for mechanical ventilation efficiency / 中国医学装备

Objective:To analyze the advantages of the pressure-regulated volume control (PRVC) mode compared with the traditional continuous mandatory ventilation (CMV) mode about mechanical ventilation efficiency of ventilator.Methods: For the mechanical ventilation situations, the parameters of PRVC mode, V-CMV mode and P-CMV mode under same detecting conditions were tested by using gas analyzer, which based on the ventilation principle of PRVC mode. And then the differences between PRVC mode and CMV modes were analyzed. Results: PRVC mode can supply the almost same tidal volume, and provide lower pressure and higher compliance compare with the V–CMV mode under the same conditions. On the other hand, PRVC mode can supply more tidal volume and slightly higher compliance compare with the P–CMV mode under the same pressure.Conclusion: PRVC mode has combined with the advantages of CMV mode, and it can make sure the target tidal volume, at the same time, reduce the pressure of airway, and improve the compliance for circuit. It also can make the mechanical ventilation to got more efficiency and more safety.

Progress of mechanical ventilation during cardiopulmonary resuscitation / 中华危重病急救医学

Mechanical ventilation is regarded as an effective means of replacing artificial ventilation during cardiopulmonary resuscitation (CPR), and has been widely used in the treatment of cardiac arrest (CA) patients. However, there are still some controversial issues remaining to be settled, such as the assessmentof the effectiveness of mechanical ventilation, the selection of the optimal oxygen concentration (FiO2), tidal volume (VT), respiratory frequency, and mode of ventilation during the CPR process. The pros and cons of positive pressure ventilation are also inconclusive. We reviewed and summarized the related research in recent years, and recommended that the intermittent positive pressure ventilation (IPPV) of volume controlled with small VT (6-7 mL/kg), low ventilation rates (10 times/min), and pure oxygen could be applied during the mechanical ventilation of CPR. The best mechanical ventilation strategy still needs further experimental researches to discover and explore.

Application of PRVC ventilation mode in one-lung ventilation during pulmonary lobectomy / 中国癌症杂志

Background and purpose:Obvious pulmonary dysfunction may exsist preoperatively in part of the patients undergoing pulmonary lobectomy. Volume-controlled ventilation (VC) during one-lung ventilation (OLV) may lead to lung injury in lung cancer patients with preoperative pulmonary dysfunction. However, pressure-regulated volume-controlled (PRVC) ventilation mode is a new type of ventilation mode, and can alleviate ventilation-induced lung injury. This study explored the effect of PRVC on respiratory mechanics, oxygenation index, pulmonary inlfam-matory response, and clinical outcomes in patients undergoing pulmonary lobectomy during OLV compared with VC mode.Methods:Forty ASAⅡ-Ⅲ patients with moderate to severe pulmonary dysfunction undergoing pulmonary lobectomy were randomly divided into group VC and group PRVC (n=20).PRVC ventilation mode was performed for patients in group VC during the ifrst 5 minutes after OLV, and then ventilation mode was switched to VC ventilation mode till the end of surgery. In the other group, ventilation modes were performed in reverse order. Ventilation settings remained unchanged when ventilation mode was switched. Respiratory mechanics, static lung compliance, hemody-namic parameters and arterial blood gas were obtained during the surgery. Blood samples and bronchoalveolar lavage (BALF) in ventilated lung were collected to determine the level of TNF-α, IL-1β, IL-6 and IL-8 at the end of surgery.Results:Both the peak expiratory pressure and static lung compliance in group PRVC were signiifcantly lower than those in group VC (P<0.01). However, there were no statistical difference in hemodynamic parameters (heart rate and blood pressure) and arterial blood gas analysis (pH,paO2andpaCO2) between the two groups during OLV, as well as postoperative pulmonary complications and length of hospital stay. The levels of TNF-α, IL-1β and IL-6 in BALF in group PRVC were signiifcantly lower than those in group VC (P<0.05), while there was no difference in blood sample. Conclusion:PRVC mode during OLV may relieve the extravagant airway pressure and then reduce the release of inlfammatory factors in ventilation lung, which might prevent acute lung injury induced by lung barotraumas, especially for those patients with pulmonary dysfunction preoperatively. Therefore, PRVC mode is a safe and effective ventilation mode for high-risk patients undergoing pulmonary lobectomy.

Application Research on Assist/Control-Mode Ventilation of Newport E150 Ventilator / 医疗卫生装备

Objective To study the ventilatory regularity of assist/control-mode ventilation(AMV/CMV or A/C) of Newport E150 ventilator. Methods The mode selector was set to A/C, the ventilatory frequencies(f1) were set at 4,6 breaths per minute(bpm) respectively. The operator inspired to meet the trigger level through the Y piece connected to corrugated hoses within the inspiratory time of CMV in group A, and inspired at the fourth and 60?f1-1second from the beginning of CMV in group B and C respectively. The appearance of AMV and CMV were recorded from the beginning of CMV to the 4+60?f1-1second. The test was repeated 20 times in each group. Results AMV was not triggered and CMV appeared at the 60?f1-1 second in group A. AMV was triggered at the fourth second and CMV appeared at the 4+60?f1-1 second in group B. AMV was triggered at the 60?f1-1 second in group C. Conclusion AMV can be triggered at any time except inspiratory time of CMV. If the ventilator can't trigger the patient's inspiratory effort from the beginning of AMV to the 60?f1-1 second, the mode will switch to CMV automatically.

A New Ventilation Mode with Simple Self-made Oxygenation Respirator / 医疗卫生装备

Objective To improve the ventilation mode for respiratory failure based on the self-made respirator. Methods For the conscious COPD patients with type II respiratory failure, nasal mask and NEEP ventilation mode were used. Patients breathe in air through the mouth and breathe out through the noses. There is no need of manual control tube to control the negative pressure in the nasal mask. For the non-typical type I respiratory failure, exhaled gas comes out from the one-way channel in the front of the mask, while oxygen for the next breathes is brought into the ball through the tube under it. Results The COPD patients breathe more freely and smoothly without disturb of the manual control tube. On the non-typical type I respiratory failure, FiO2 is much higher and without breath in CO2. Conclusion The new ventilation mode can provide a great range of FiO2 and get ride of redundant CO2. It's beneficial to the recovery of patients.

Development of High Frequency Ventilators / 医疗卫生装备

High frequency ventilators(HFV) are introduced in such aspects as its contribution to the development of the ventilation, phylogeny, working principle in the physiological field, the advantages over normal-frequency ventilation, three common HFV modes and their application to medical therapy. The present situation of HFV is analyzed as well as it's developing trends and prospects.