Effects of pressure controlled ventilation-volume guaranteed mode on intraoperative pulmonary ventilation and postoperative pulmonary complications in elderly patients undergoing thoracoscopic lobectomy / 肿瘤研究与临床

Objective:To explore the effects of pressure controlled ventilation-volume guaranteed (PCV-VG) mode on intraoperative pulmonary ventilation and postoperative pulmonary complications (PPC) in elderly patients undergoing thoracoscopic lobectomy.Methods:Sixty patients of American Society of Anesthesiologists (ASA) classification Ⅱor Ⅲ, aged 65-80 years old, with body mass index (BMI) 18-30 kg/m 2, received thoracoscopic lobectomy under general anesthesia from November 2021 to June 2022 in the Second Hospital of Shanxi Medical University were recruited. The patients were divided into PCV-VG and volume-controlled ventilation (VCV) groups using the randomized number table method, with 30 patients in each group. The ventilatory parameters of two-lung ventilation were set to respiratory rate (RR) at 10-12 breaths/min, with a tidal volume (VT) of 8 ml/kg (ideal body weight). The ventilatory parameters of one-lung ventilation (OLV) were set at 12-16 breaths/min, with a VT of 6 ml/kg (IBW). The peak airway pressure (Ppeak), plateau airway pressure (Pplat), driving pressure (ΔP), dynamic lung compliance (Cdyn), end-tidal carbon dioxide (ETCO 2), heart rate (HR), mean arterial pressure (MAP), partial pressure of oxygen (PaO 2) and partial pressure of carbon dioxide (PaCO 2) were obtained at 1 min before OLV (T 0), 30 min after OLV (T 1) and 60 min after OLV (T 2). The incidence and severity of PPC, chest tube duration time and postoperative hospital stay time were recorded. Results:The Ppeak, Pplat and ΔP were higher and Cdyn was lower in both groups at T 1-T 2 than at T 0 (all P<0.001). The Ppeak, Pplat and ΔP were higher and Cdyn was lower in PCV-VG group than in VCV group (all P<0.05). There were no statistical differences in HR, MAP, ETCO 2, PaO 2 and PaCO 2 between the two groups (all P > 0.05). There were no statistical differences in the incidence of PPC [43.3% (13/30) vs. 30.0% (9/30)] and chest tube duration time [(4.4±0.9) d vs. (4.2±1.2) d] between VCV group and PCV-VG group (all P>0.05). Compared with VCV group, the proportion of patients with ≥grade 2 PPC was lower in PCV-VG group [10.0% (3/30) vs. 36.7% (11/30), χ2=5.96, P<0.05]. The postoperative hospital stay time in PCV-VG group was shorter than that in VCV group [(6.4±1.3) d vs. (8.0±1.9) d, t = 4.85, P<0.05]. Conclusions:PCV-VG mode can effectively reduce the severity of PPC, shorten the postoperative hospital stay time and improve the prognosis in elderly patients undergoing thoracoscopic lobectomy.

Effect of intraoperative ventilation modes on postoperative pulmonary complications after cardiac surgery under cardiopulmonary bypass: A retrospective cohort study / 中国胸心血管外科临床杂志

@#Objective    To evaluate the association of intraoperative ventilation modes with postoperative pulmonary complications (PPCs) in adult patients undergoing selective cardiac surgery under cardiopulmonary bypass (CPB). Methods    The clinical data of 604 patients who underwent selective cardiac surgical procedures under CPB in the West China Hospital, Sichuan University from June to December 2020 were retrospectively analyzed. There were 293 males and 311 females with an average age of 52.0±13.0 years. The patients were divided into 3 groups according to the ventilation modes, including a pressure-controlled ventilation-volume guarantee (PCV-VG) group (n=201), a pressure-controlled ventilation (PCV) group (n=200) and a volume-controlled ventilation (VCV) group (n=203). The association between intraoperative ventilation modes and PPCs (defined as composite of pneumonia, respiratory failure, atelectasis, pleural effusion and pneumothorax within 7 days after surgery) was analyzed using modified poisson regression. Results    The PPCs were found in a total of 246 (40.7%) patients, including 86 (42.8%) in the PCV-VG group, 75 (37.5%) in the PCV group and 85 (41.9%) in the VCV group. In the multivariable analysis, there was no statistical difference in PPCs risk associated with the use of either PCV-VG mode (aRR=0.951, 95%CI 0.749-1.209, P=0.683) or PCV mode (aRR= 0.827, 95%CI 0.645-1.060, P=0.133) compared with VCV mode. Conclusion    Among adults receiving selective cardiac surgery, PPCs risk does not differ significantly by using different intraoperative ventilation modes.

Comparison of volume-controlled and pressure-controlled ventilation on respiratory mechanics in laparoscopic bariatric surgery: randomized clinical trial / Comparação das ventilações controlada por volume e controlada por pressão na mecânica respiratória em cirurgia bariátrica laparoscópica: estudo clínico randômico

Abstract Background: It is not clear which mechanical ventilation mode should be used in bariatric surgery, one of the treatment options for patients with obesity. Objectives: To compare volume-controlled ventilation and pressure-controlled ventilation in terms of respiratory mechanics and arterial blood gas values in patients undergoing laparoscopic bariatric surgery. Methods: Sixty-two patients with morbid obesity scheduled for gastric bypass were included in this study. Their ideal body weights were calculated during preoperative visits, and patients were divided into two groups, volume-controlled ventilation and pressure-controlled ventilation. The patients were ventilated in accordance with a previously determined algorithm. Mechanical ventilation parameters and arterial blood gas analysis were recorded 5minutes after induction, 30minutes after pneumoperitoneum, and at the end of surgery. Also, the dynamic compliance, inspired O2 pressure/fractional O2 ratio, and alveolar-arterial oxygen gradient pressure were calculated. Results: Peak airway pressures were lower in patients ventilated in pressure-controlled ventilation mode at the end of surgery (p = 0.011). Otherwise, there was no difference between groups in terms of intraoperative respiratory parameters and arterial blood gas analyses. Conclusions: Pressure-controlled ventilation mode is not superior to volume-controlled ventilation mode in patients with laparoscopic bariatric surgery.

Resumo Justificativa: O modo de ventilação mecânica que deve ser usado em cirurgia bariátrica, uma das opções de tratamento para pacientes com obesidade, ainda não foi definido. Objetivos: Comparar as ventilações controladas por volume e por pressão em termos de mecânica respiratória e dos valores da gasometria arterial em pacientes submetidos à cirurgia bariátrica laparoscópica. Métodos: Foram incluídos neste estudo 62 pacientes com obesidade mórbida programados para bypass gástrico. Seus pesos corporais ideais foram calculados durante as consultas pré-operatórias e os pacientes foram divididos em dois grupos: ventilação controlada por volume e ventilação controlada por pressão. Os pacientes foram ventilados de acordo com um algoritmo previamente determinado. Os parâmetros da ventilação mecânica e as análises da gasometria arterial foram registrados 5 minutos após a indução, 30 minutos após o pneumoperitônio e ao final da cirurgia. Além disso, a complacência dinâmica, a pressão e a fração de oxigênio inspirado e a pressão do gradiente alvéolo-arterial de oxigênio foram calculados. Resultados: As pressões de pico das vias aéreas foram menores nos pacientes ventilados no modo de ventilação controlada por pressão ao final da cirurgia (p = 0,011). Exceto por esse aspecto, não houve diferença entre os grupos quanto aos parâmetros respiratórios intraoperatórios e às gasometrias arteriais. Conclusões: O modo de ventilação controlada por pressão não é superior ao modo de ventilação controlada por volume em pacientes de cirurgia bariátrica laparoscópica.

Effects of small tidal volume and positive end-expiratory pressure on oxygenation in pressure-controlled ventilation-volume guaranteed mode during one-lung ventilation / 영남의대학술지

BACKGROUND: The purpose of this study was to investigate whether tidal volume (TV) of 8 mL/kg without positive end-expiratory pressure (PEEP) and TV of 6 mL/kg with or without PEEP in pressure-controlled ventilation-volume guaranteed (PCV-VG) mode can maintain arterial oxygenation and decrease inspiratory airway pressure effectively during one-lung ventilation (OLV).METHODS: The study enrolled 27 patients undergoing thoracic surgery. All patients were ventilated with PCV-VG mode. During OLV, patients were initially ventilated with TV 8 mL/kg (group TV8) without PEEP. Ventilation was subsequently changed to TV 6 mL/kg with PEEP (5 cmH₂O; group TV6+PEEP) or without (group TV6) in random sequence. Peak inspiratory pressure (P(peak)), mean airway pressure (P(mean)), and arterial blood gas analysis were measured 30 min after changing ventilator settings. Ventilation was then changed once more to add or eliminate PEEP (5 cmH₂O), while maintaining TV 6 mL/kg. Thirty min after changing ventilator settings, the same parameters were measured once more.RESULTS: The P(peak) was significantly lower in group TV6 (19.3±.3 cmH₂O) than in group TV8 (21.8±3.1 cmH₂O) and group TV6+PEEP (20.1±3.4 cmH₂O). PaO₂ was significantly higher in group TV8 (242.5±111.4 mmHg) than in group TV6 (202.1±101.3 mmHg) (p=0.044). There was no significant difference in PaO₂ between group TV8 and group TV6+PEEP (226.8±121.1 mmHg). However, three patients in group TV6 were dropped from the study because PaO₂ was lower than 80 mmHg after ventilation.CONCLUSION: It is postulated that TV 8 mL/kg without PEEP or TV 6 mL/kg with 5 cmH₂O PEEP in PCV-VG mode during OLV can safely maintain adequate oxygenation.

Effect of Trendelenburg position and artificial pneumoperitoneum on change of respiratory mechanics in-dexes due to change of preset airway pressure in PCV / 实用医学杂志

Objective In pressure controlled ventilation(PCV),a self-control method was used to ob-serve the change of respiration mechanics indexes under Trendelenburg position and pneumoperitoneum versus su-pine position and non-pneumoperitoneum with preset airway pressure.Methods Thirty patients scheduled for lapa-roscopic radical resection of rectal carcinoma were enrolled in this study.ECG,MAP,SpO2,BIS and body temper-ature were routinely detected. After induction of anesthesia,volume controlled ventilation(VCV)was used as ba-sic ventilation,and then switched to PCV after 5 minutes. The airway pressure was the preset airway pressure be-fore pneumoperitoneum,then was lowered 1 cmH2O in proper order,and then restored preset airway pressure and increased 1 cmH2O. 15 minutes after pneumoperitoneum,the airway pressure of PCV was used as preset airway pressure after pneumoperitoneum,and then the above procedure was repeated.The time interval was at least 5 min-utes.The values of MAP,HR,SpO2,VT and Cdyn were recorded at each time;VT,and Cdyn were continuously recorded five times to take the average value. The postoperative recovery in patients was observed. Results After pneumoperitoneum,the values of Cdyn and VT were significantly reduced(P < 0.01),MAP was increased(P <0.05). When the preset airway pressure changed 1 cmH2O,ΔVT was decreased(P < 0.05),and the change of Cdyn was not statistically significant. Conclusions As altering a unit of the preset airway pressure in PCV,the change in VT is significantly reduced but Cdyn does not change markedly in Trendelenburg posture and artificial pneumoperitoneum,as compared with supine position and non-pneumoperitoneum.

Ventilación controlada por volumen y por presión en pacientes con enfermedades respiratorias crónicas intervenidos quirúrgicamente / Volume- and pressure-controlled ventilation in surgically intervened patients with chronic respiratory diseases

Fundamento: Existe una alta frecuencia en nuestro medio de pacientes con enfermedad pulmonar obstructiva crónica y asma bronquial que requieren intervenciones quirúrgicas electivas y precisan de anestesia general con ventilación mecánica controlada por volumen y por presión. Objetivo: Comparar ambos métodos de ventilación controlada en los pacientes con enfermedades respiratorias crónicas intervenidos quirúrgicamente de forma electiva en el Hospital Universitario Manuel Ascunce Domenech de Camagüey. Métodos: Estudio observacional analítico. El universo comprendió 83 pacientes y la muestra por 40 pacientes. Se conformaron dos grupos de estudio: grupo I, en el cual se utilizó la ventilación controlada por volumen y se prefijó el volumen tidal a 7 mL/kg, con frecuencia respiratoria de 10-12 respiraciones por minuto, índice de inspiración-espiración 1:2 y FiO2 de 20,5 por ciento, y grupo II, en el cual se empleó la ventilación controlada por presión y se prefijó la presión inspiratoria pico ideal para garantizar el volumen minuto adecuado en el paciente, con frecuencia respiratoria de 10-12 respiraciones por minuto, índice de inspiración-espiración 1:2 y FiO2 0,5 por ciento. En ambos grupos se calculó la compliance dinámica y se determinó la relación presión arterial de oxígeno y fracción inspirada de oxígeno. Resultados: Se encontraron cifras mayores de la relación PO2/FiO 2, cifras de PIP más bajas y una mejor compliance dinámica en el grupo II. Conclusiones: La ventilación controlada por presión es una modalidad ventilatoria que ofrece al paciente adecuada oxigenación con mejor compliance y control de la presión inspiratoria pico(AU)

Background: Our scenario presents high frequency of patients with chronic obstructive pulmonary disease and bronchial asthma and who require elective surgery and general anesthesia with volume- and pressure-controlled mechanical ventilation. Objective: To compare both methods of controlled ventilation in patients with chronic respiratory diseases electively operated at Manuel Ascunce Domenech University Hospital in Camagüey. Methods: Analytical, observational study. The universe comprised 83 patients and the sample comprised 40 patients. Study group I, in which volume-controlled ventilation was used, and volume was adjusted to 7 mL/kg, with respiratory rate of 10-12 breaths per minute, inspiratory-expiration ratio 1:2, and FiO 2 at 20.5 percent; and group II, in which pressure-controlled ventilation was used and the ideal peak inspiratory pressure was set to ensure the patient's adequate volume per minute, respiratory rate of 10-12 breaths per minute, inspiratory-expiration index 1:2, and FiO2 at 0.5 percent. Dynamic compliance was calculated in both groups and the relationship between oxygen arterial pressure and inspired oxygen fraction was determined. Results: We found higher numbers of the PO2/FiO2 ratio, lower PIP numbers and better dynamic compliance in group II. Conclusions : Pressure-controlled ventilation is a ventilation modality that offers the patient adequate oxygenation with better compliance and control of peak inspiratory pressure(AU)

Comparison of Effects of Pressure Controlled Ventilation and Volume Controlled Ventilation on Perioperative Blood Loss of Patients with Posterior Lumbar Interbody Fusion / 医学研究杂志

Objective To compare the effects of pressure controlled ventilation and volume controlled ventilation on perioperative blood loss of patients with posterior lumbar interbody fusion (PLIF).Methods According to the random number table method,a total of 88 patients scheduled to PLIF were allocated into two groups,44 cases per groups.Patients received respectively pressure controlled ventilation and volume controlled ventilation in pressure controlled ventilation group (PCV group) and volume controlled ventilation group (VCV group).Mean arterial blood pressure (MAP),heart rate (HR) and central venous pressure (CVP) were continuously monitored at anesthesia induction immediately (T0),10min after supine position to prone position (T1),skin suture immediately (T2),10min after prone position to supine position (T3) and when tracheal extubation (T4).Hemoglobin (Hb) and hematokrit (HCT) were tested from T0 to T4 in the two groups.Respiratory parameters were recorded from T0 to T3 in the two groups.Intraoperative blood loss and blood loss at 96h after operation patients were recorded.Allogeneic blood transfusion,volume of fluid input and the rate of secondary surgery to stop th bleeding were recorded in the two groups.Results Compared to VCV group,peak inspimtory pressure (PIP) from T1 to T3 were all significantly lower (P ＜0.05) in PCV group.There was no statistical significance (P ＞ 0.05) in MAP,HR,tidal volume,respiratory rate (RR),PaO2/FiO2 and PaCO2 between the two groups.There was no statistical significance (P ＞ 0.05) in Hb and Hct at different time points between the two groups.Compared to VCV group,intraoperative blood loss,plasma infusions and red blood cell infusions were al significantly lower (P ＜ 0.05) in PCV group.Conclusion PCV can decrease intraoperative blood loss of patients with PLIF,which may be related to lower PIP during operation.

Application of pressure-controlled ventilation-volume guaranteed in obese patients with obstructive sleep apnea syndrome / 实用医学杂志

Objective To explore the clinical effectiveness of pressure-controlled ventilation-volume guar-anteed(PCV-VG)in obese patients with obstructive sleep apnea syndrome(OSAS)during uvulopalatopharyngo-plasty. Methods 40 obese patients(BMI≥30 kg/m2)with OSAS scheduled for uvulopalatopharyngoplasty under general anesthesia were randomly divided into two groups of volume-controlled ventilation(group V,n = 20)and pressure-controlled ventilation-volume guaranteed(group P,n=20). The heart rate(HR),mean arterial pressure (MAP),arterial partial pressure of oxygen(PaO2)and arterial partial pressure of carbondioxide(PaCO2)were recorded before induction of anesthesia without oxygen inhalation(T0),30 min(T1)and 1 h(T2)after tracheal intubation,and 30 min after extubation(T3). The peak airway pressure(Ppeak),airway resistance(Raw),thoracic compliance (CL),oxygenation index (OI) and respiratory index (RI) were also calculated at T1 and T2 under observation of recovery. Results There were no obvious differences between the two groups of patients before anesthesia and after recovery. Compared with the group V ,PaCO2 ,PPEAK ,Raw at T1 ,T2 and RI at T1 ~ T3 of the group P decreased(P<0.05),while CL at T1,T2 and PaO2,OI at T1~T3 increased(P<0.05). There were no sig-nificant differences in HR ,MAP at the above time points. Conclusions Compared with volume-controlled venti-lation,PCV-VG can effectively enhance thoracic compliance,lower inspiratory pressure and airway resistance ,and decrease intrapulmonary shunt ,which is conductive to improve arterial oxygenation and gas exchange in obese patients with OSAS.

Influencia del tiempo inspiratorio prolongado durante la ventilación transoperatoria controlada por presión / The influence of lengthening the inspiration time during pressure-controlled intraoperative ventilation

Introducción: la enfermedad pulmonar obstructiva crónica es la sexta causa de muerte a nivel mundial. La prolongación del tiempo inspiratorio es una práctica con ventajas y desventajas. Objetivo: comparar los beneficios de diferentes tiempos inspiratorios sobre la oxigenación, las presiones en la vía respiratorias y las variaciones hemodinámicas. Métodos: estudio analítico longitudinal prospectivo con un grupo. Universo de 36 pacientes que cumplieron con los criterios de inclusión. Resultados: la media de la edad fue de 70,5 años ± 8,3 años, el 59 por ciento fueron mujeres. El 38,7 por ciento fueron hipertensos, y el 41,2 por ciento cardiópatas. Las presiones pico fueron de 26,6 mbar Ti corto y en el Ti largo 19,1 mbar (t student 1,28). Las medias de las presiones mesetas se comportaron diferentes con Ti corto de 20,6 mbar y Ti largo 19,6 mbar con t student de 0,04. Las medias de las frecuencias respiratorias en el Ti corto fueron de 12,6 resp/min y en el Ti largo 10,7 resp/min con t student fue de 5,92. La relación entre saturación de oxigeno/fracción inspirada de oxigeno en el Ti corto fue de 243 y en el Ti largo 248, pero la t student fue de 5,9. Conclusiones: la prolongación del tiempo inspiratorio durante la ventilación intraoperatoria controlada por presión en pacientes con enfermedad pulmonar obstructiva crónica es ventajosa porque reduce las presiones de la vía respiratoria y mantiene los parámetros de oxigenación y hemodinámicos con relación al tiempo inspiratorio convencional, por lo que pudiera ser una alternativa para el manejo anestésico de estos pacientes(AU)

Introduction: Chronic obstructive pulmonary disease is the sixth leading cause of death worldwide. Lengthening the inspiration time is a practice with advantages and disadvantages. Objective: To compare the benefits of different inspiration times on oxygenation, airway pressures and hemodynamic changes. Methods: Prospective longitudinal analytic study with a group. Sample group of 36 patients who met the inclusion criteria. Results: The mean age was 70.5 years ± 8.3 years, 59 percent were women. 38.7 percent were hypertensive, and 41.2 percent were cardiac patients. The peak pressures were 26.6 mbar in the short Ti and 19.1 mbar in the long Ti (Student's t-distribution was 1.28). The means of the plateau pressure behaved different: with short Ti, 20.6 mbar, and with long Ti, 19.6 mbar, with Student's t-distribution: 0.04. Mean respiratory rates in the short Ti were 12.6 breaths/min and in the long Ti, 10.7 breaths/min, with Student's t-distribution 5.92. The relation between oxygen saturation and fraction of inspired oxygen in the Ti short was 243 and in the long Ti was 248, but the Student's t-distribution was 5.9 t. Conclusions: Lengthened inspiratory time during intraoperative pressure-controlled ventilation in patients with chronic obstructive pulmonary disease is advantageous because it reduces the airway pressure and maintains oxygenation and hemodynamic parameters versus conventional inspiration time, so it could be an alternative for the anesthetic management of these patients(AU)

Pressure support ventilation with the I-gel in intensive care unit: case report / Ventilação controlada por pressão com I-gel em unidade de terapia intensiva: relato de caso

ABSTRACT BACKGROUND AND OBJECTIVES: The I-gel supraglottic airway has a non-inflatable cuff made from a gel-like thermoplastic elastomer. The use of the I-gel during anesthesia for spontaneously breathing patients or intermittent positive pressure ventilation has been reported. But there are a few published reports about the use of the I-gel with pressure-controlled ventilation. CONTENTS AND CONCLUSIONS: In this case report we described the use of the I-gel supraglottic airway along 48 h in intensive care unit for the management of ventilation in a patient needed mechanic ventilation but in whom tracheal intubation could not be performed.

RESUMO JUSTIFICATIVA E OBJETIVOS: O dispositivo supraglótico I-gel para o manejo das vias aéreas tem um manguito não insuflável feito de um elastômero termoplástico semelhante ao gel. Há relato sobre o uso do I-gel em pacientes sob anestesia para a ventilação, espontânea ou com pressão positiva intermitente. Porém, há poucos relatos publicados sobre o uso do I-gel com ventilação controlada por pressão. CONTEÚDO E CONCLUSÕES: Descrevemos neste relato de caso o uso do dispositivo supraglótico I-gel durante 48 horas em unidade de terapia intensiva para o manejo das vias aéreas em paciente que precisou de ventilação mecânica, mas no qual a intubação traqueal não pôde ser feita.

Effect of different modes of ventilation on PaO2 and PaCO2 in laparoscopic surgery in the Trendelenburg position / 临床麻醉学杂志

Objective To investigate the effects of different ventilation modes on PaCO 2 and PaO 2 during laparoscopic surgery in the Trendelenburg position.Methods Forty cases of laparoscopic resection of rectal cancer were randomly divided into group A (n =20)and group B (n =20).Under general anesthesia,all the cases were in volume-controlled ventilation mode (VCV,tidal volume=10 ml/kg)before pneumoperitoneum.After ventilating in VCV mode for 20 minutes with a lower tidal volume (8 ml/kg),group A was converted to PCV mode for 20 minutes and then back to the VCV mode for 20 minutes again.Next we switched to PCV combined with PEEP (5 cm H 2 O)mode (PCV+PEEP)for 20 minutes.In group B,we only alternated PCV with PCV combined with PEEP.Arte-rial blood-gas analysis was obtained at each time when ventilating mode changed.Results In both group A and B,PaO 2 in VCV mode was less than that in PCV mode and PCV+PEEP mode (P <0.05),PaO 2 in PCV mode was also less than that in mode PCV+PEEP mode (P <0.05).PaCO 2 in PCV and PCV combined with PEEP mode was less than that in VCV mode (P <0.05 ),and there was no difference of PaCO 2 in PCV mode and PCV+PEEP mode.The pH value in VCV mode was less than that in PCV mode and PCV+PEEP mode (P < 0.05).There was no difference in pH value between PCV mode and PCV+PEEP mode.Conclusion PCV combined PEEP mode is beneficial ei-ther in increasing or decreasing of PaCO 2 during laparoscopic surgery in the Trendelenburg position comparing with single VCV mode or PCV mode.

Effects of Different Ventilation Modes on Respiration and Circulation in Elderly Patients Undergoing Thoracic Surgery / 昆明医科大学学报

Objective The aim of this study was to explore the effects of volume controlled ventilation (VCV),pressure controlled ventilation(PCV)and pressure controlled ventilation-volume guaranteed (PCV-VG)on respiration and circulation in elderly patients undergoing thoracic surgery. Methods Thirty-six elderly patients who underwent thoracic surgery were enrolled in our study. Patients were divided into VCV,PCV and PCV-VG groups according to randomized design. The hemodynamic and respiratory data and the arterial blood gases had been recorded in the pre-operation,20 min,40 min,60 min after OLV and 20 min after the resumption of two lung ventilation. Results Compared with VCV group,Ppeak value was significantly lower in PCV and PCV-VG groups(P 0.05). Conclusion Compared with VCV,the use of PCV and PCV-VG have significant advantages in the operative oxygenation and airway pressure for elderly patients undergoing OLV.

Comparison of volume-controlled and pressure-controlled ventilation in the Trendelenburg position for gynecological laparoscopic surgery

BACKGROUND: Minimal invasive gynecologic surgery usually requires pneumoperitoneum and Trendelenburg positioning, which results in adverse effects on respiratory and hemodynamic parameters. The aim of this study was to investigate the effects of volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) introduced sequentially in patients who underwent gynecological laparoscopy on respiratory mechanics, cardiovascular responses, and gas exchange. METHODS: Forty patients who were scheduled for gynecologic laparoscopic surgery were enrolled. Baseline ventilation of their lungs was performed with VCV with a tidal volume (TV) of 8 ml/kg ideal body weight (IBW). Forty minutes after pneumoperitoneum and Trendelenburg positioning, the ventilation mode was changed to PCV, and airway pressure was set to provide a TV of 8 ml/kg IBW without exceeding 35 cmH2O. Respiratory mechanics and hemodynamic and gas exchange parameters were recorded at 10 minutes after induction, 30 minutes after CO2 pneumoperitoneum and Trendelenburg positioning, 30 minutes after PCV, and 30 minutes after desufflation and supine position. RESULTS: After pneumoperitoneum and Trendelenburg positioning, there were significant increases in systolic blood pressure, diastolic blood pressure, central venous pressure, peak airway pressure (PAP), mean airway pressure (Pmean), whereas lung compliance and PaO2 significantly decreased. The decrease in PAP and increases of Pmean, lung compliance and PaO2 were observed during PCV compared with VCV (P < 0.05). There were no differences in hemodynamic parameters between VCV and PCV. CONCLUSIONS: Our results demonstrated that PCV may be an effective method of ventilation during gynecologic laparoscopy in terms of improved oxygenation and minimizing adverse respiratory mechanics.

Auto-PEEP-like condition recognized by a sudden decrease in airway pressure during pressure controlled ventilation and low-flow anesthesia: A case report

During mechanical ventilation in the intensive care unit, auto-positive end-expiratory pressure (auto-PEEP) has been reported to occur in obstructive airway conditions aggravated by inappropriate ventilator settings. In this paper, we report a case of auto-PEEP-like problem during anesthesia, mainly caused by excessive sputum. After being positioned prone for spine surgery, the patient received pressure controlled ventilation at a low fresh gas flow rate. One hour after the start of surgery, sudden decreases in pressure and flow occurred. The typical maneuvers which could be performed by the anesthesiologists in the situations suggesting leakage within the breathing circuit consist of pressing the oxygen flush valve and manual hyperventilation for the initial evaluation. But from our experience in this case, we have learned that such maneuvers could cause unacceptable aggravation in the event of auto-PEEP. Also in this report, we discuss the difficulties in prediction based on the present knowledge of preoperative evaluation and the presumably best management policy regarding this type of auto-PEEP.

Analysis on potential risk of critical patients due to the difference of airway peak pressure of invasive ventilator in pressure controlled ventilation mode / 中国医学装备

Objective:To reveal the difference of airway peak pressure of different brands and models invasive ventilator in our hospital through test and analysis, and reveal that the difference might bring potential threat to the critical patients.Methods: Using adult simulated lung with adjustable respiratory resistance and compliance as the load of invasive ventilator to measure airway peak pressure of invasive ventilator in constant pressure controlled ventilation mode. Results: The results showed that the measured ventilators surely have differences in airway peak pressure in constant pressure controlled ventilation mode.Conclusion: For severe patients, if we ignore the peak airway pressure difference between invasive ventilators, there may be a threat to the critical patients.

Volume-controlled versus pressure-controlled ventilation-volume guaranteed mode during one-lung ventilation / 대한마취과학회지

BACKGROUND: The purpose of this study was to investigate the changes in airway pressure and arterial oxygenation between ventilation modes during one-lung ventilation (OLV) in patients undergoing thoracic surgery. METHODS: We enrolled 27 patients for thoracic surgery with OLV in the lateral decubitus position. The subjects received various modes of ventilation in random sequences during surgery, including volume-controlled ventilation (VCV) and pressure-controlled ventilation-volume guaranteed (PCV-VG) with a tidal volume (TV) of 8 ml/kg of actual body weight. Target-controlled infusion (TCI) with propofol and remifentanil was used for anesthesia induction and maintenance. After double-lumen endobronchial tube (DLT) insertion, the proper positioning of the DLT was assessed using a fiberoptic bronchoscope. Peak inspiratory pressure (Ppeak), exhaled TV, and arterial blood gas were measured 30 min after each ventilation mode. RESULTS: P(peak) was significantly reduced with the PCV-VG mode (19.6 +/- 2.5 cmH2O) compared with the VCV mode (23.2 +/- 3.1 cmH2O) (P < 0.000). However, no difference in arterial oxygen tension was noted between the groups (PCV-VG, 375.8 +/- 145.1 mmHg; VCV, 328.1 +/- 123.7 mmHg) (P = 0.063). The exhaled TV was also significantly increased in PCV-VG compared with VCV (451.4 +/- 85.4 vs. 443.9 +/- 85.9 ml; P = 0.035). CONCLUSIONS: During OLV in patients with normal lung function, although PCV-VG did not provide significantly improved arterial oxygen tension compared with VCV, PCV-VG provided significantly attenuated airway pressure despite significantly increased exhaled TV compared with VCV.

Volume-controlled versus pressure-controlled ventilation-volume guaranteed mode during one-lung ventilation / 대한마취과학회지

BACKGROUND: The purpose of this study was to investigate the changes in airway pressure and arterial oxygenation between ventilation modes during one-lung ventilation (OLV) in patients undergoing thoracic surgery. METHODS: We enrolled 27 patients for thoracic surgery with OLV in the lateral decubitus position. The subjects received various modes of ventilation in random sequences during surgery, including volume-controlled ventilation (VCV) and pressure-controlled ventilation-volume guaranteed (PCV-VG) with a tidal volume (TV) of 8 ml/kg of actual body weight. Target-controlled infusion (TCI) with propofol and remifentanil was used for anesthesia induction and maintenance. After double-lumen endobronchial tube (DLT) insertion, the proper positioning of the DLT was assessed using a fiberoptic bronchoscope. Peak inspiratory pressure (Ppeak), exhaled TV, and arterial blood gas were measured 30 min after each ventilation mode. RESULTS: P(peak) was significantly reduced with the PCV-VG mode (19.6 +/- 2.5 cmH2O) compared with the VCV mode (23.2 +/- 3.1 cmH2O) (P < 0.000). However, no difference in arterial oxygen tension was noted between the groups (PCV-VG, 375.8 +/- 145.1 mmHg; VCV, 328.1 +/- 123.7 mmHg) (P = 0.063). The exhaled TV was also significantly increased in PCV-VG compared with VCV (451.4 +/- 85.4 vs. 443.9 +/- 85.9 ml; P = 0.035). CONCLUSIONS: During OLV in patients with normal lung function, although PCV-VG did not provide significantly improved arterial oxygen tension compared with VCV, PCV-VG provided significantly attenuated airway pressure despite significantly increased exhaled TV compared with VCV.

Comparison of volume-controlled and pressure-controlled ventilation using a laryngeal mask airway during gynecological laparoscopy / 대한마취과학회지

BACKGROUND: Several publications have reported the successful, safe use of Laryngeal Mask Airway (LMA)-Classic devices in patients undergoing laparoscopic surgery. However, there have been no studies that have examined the application of volume-controlled ventilation (VCV) or pressure-controlled ventilation (PCV) using a LMA during gynecological laparoscopy. The aim of this study is to compare how the VCV and PCV modes and using a LMA affect the pulmonary mechanics, the gas exchange and the cardiovascular responses in patients who are undergoing gynecological laparoscopy. METHODS: Sixty female patients were randomly allocated to one of two groups, (the VCV or PCV groups). In the VCV group, baseline ventilation of the lung was performed with volume-controlled ventilation and a tidal volume of 10 ml/kg ideal body weight (IBW). In the PCV group, baseline ventilation of the lung using pressure-controlled ventilation was initiated with a peak airway pressure that provided a tidal volume of 10 ml/kg IBW and an upper limit of 35 cmH2O. The end-tidal CO2, the peak airway pressures (Ppeak), the compliance, the airway resistance and the arterial oxygen saturation were recorded at T1: 5 minutes after insertion of the laryngeal airway, and at T2 and T3: 5 and 15 minutes, respectively, after CO2 insufflation. RESULTS: The Ppeak at 5 minutes and 15 minutes after CO2 insufflation were significantly increased compared to the baseline values in both groups. Also, at 5 minutes and 15 minutes after CO2 insufflation, there were significant differences of the Ppeak between the two groups. The compliance decreased in both groups after creating the pneumopertoneim (P < 0.05). CONCLUSIONS: Our results demonstrate that PCV may be an effective method of ventilation during gynecological laparoscopy, and it ensures oxygenation while minimizing the increases of the peak airway pressure after CO2 insufflation.

Ventilación por presión en cirugía torácica / Pressure ventilation in thoracic surgery

Introducción: La ventilación controlada por presión es un modo de ventilación ampliamente utilizado en el fallo respiratorio severo, donde ha demostrado que mejora la oxigenación arterial. Objetivo: Comparar la ventilación controlada por volumen comúnmente utilizado durante la ventilación unipulmonar con tres estrategias ventilatorias de ventilación controlada por presión. Método: Se realizó un estudio comparativo y prospectivo de 100 pacientes tratados por cirugía torácica divididos en cuatro grupos según modo ventilatorio utilizado. Grupo I VCV, con volumen minuto 100 mL/kg. Grupo II VCP con Vot de 10 mL/kg, Grupo III VCP con Vot de 8 mL/kg, y Grupo IV VCP con 5cm de H2O de PEEP y un Vot de 8 mL/kg. Se comparó PaO2, SatO2, Shunt Intrapulmonar, Presión Pico y Meseta a los 30 minutos de la ventilación unipulmonar y los episodios de desaturación arterial. Se utilizó Chi Cuadrado y ANOVA para el análisis estadístico. Resultados: La PaO2 presentó valores similares en los Grupos I y II, 148,28 ± 68,21 y 146,8 ± 67,8 mmHg, respectivamente, disminuyó en el Grupo III a 117,2 ± 51,0 mmHg y aumentó significativamente en el Grupo IV 189,0 ± 49,2 mmHg. La SatO2 se incrementó y el shunt intrapulmonar disminuyó con significación estadística en el Grupo IV. Las presiones en la vía aérea fueron menores durante la VCP. Conclusión: La ventilación controlada por presión "per se" no mejoró las variables de oxigenación durante la ventilación unipulmonar, pero sí, permite alcanzar menores presiones en la vía aérea. La administración de PEEP durante la ventilación controlada por presión evidenció mejoría significativa de la oxigenación.

Introduction: Pressure controlled ventilation is a very used way of ventilation in severe respiratory failure, where it has been showed that it improves arterial oxygenation. Objective: To compare volume controlled ventilation commonly used during unipulmonar ventilation with three ventilator strategies of pressure controlled ventilation. Method: We made a comparative and prospective study of 100 patients undergoing thoracic surgery divided into 4 groups by ventilator mode used: group I VCV with a minute volume 100 mL/kg, group II VCP with Vot of 10 mL/kg, group III VCP with Vot of 8 mL/kg, and group IV VCP with 5 cm of H2O of PEEP, and a Vot of 8 mL/kg. We compared PaO2, SatO2, intrapulmonary shunt, peak and plateau pressures at 30 minutes of unipulmonar ventilation, and the arterial desaturation episodes. We used Chi2 and ANOVA for statistical analysis. Results: The PaO2 yields similar values in Groups I and II, 148,28 ± 68,21 and 146,8 ± 67,8 mmHg, respectively, it decreased in Group III to 117,2 ± 51,0 mmHg, and then increased significantly in group IV 189,0 ± 49,2 mmHg. The SatO2 increased and intrapulmonary shunt decreased with statistical significance in group IV. Airway pressures were low during VCP. Conclusion: Pressure controlled ventilation "per se" not improved oxygenation variables during unipulmonar ventilation, but allowing lower pressures in airway. Administration of PEEP during pressure controlled evidenced a significant improvement of oxygenation.

The Effect and Safety of Alveolar Recruitment Maneuver using Pressure-Controlled Ventilation in Acute Lung Injury and Acute Respiratory Distress Syndrome / 결핵및호흡기질환

BACKGROUND: Alveolar recruitment (RM) is one of the primary goals of respiratory care for an acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). The purposes of alveolar recruitment are an improvement in pulmonary gas exchange and the protection of atelectrauma. This study examined the effect and safety of the alveolar RM using pressure control ventilation (PCV) in early ALI and ARDS patients. METHODS: Sixteen patients with early ALI and ARDS who underwent alveolar RM using PCV were enrolled in this study. The patients' data were recorded at the baseline, and 20 minutes, and 60 minutes after alveolar RM, and on the next day after the maneuver. Alveolar RM was performed with an inspiratory pressure of 30 cmH2O and a PEEP of 20 cmH2O in a 2-minute PCV mode. The venous O2 saturation, central venous pressure, blood pressure, pulse rate, PaO2/FiO2 ratio, PEEP, and chest X-ray findings were obtained before and after alveolar RM. RESULTS: Of the 16 patients, 3 had extra-pulmonary ALI/ARDS and the remaining 13 had pulmonary ALI/ARDS. The mean PEEP was 11.3 mmHg, and the mean PaO2/FiO2 ratio was 130.3 before RM. The PaO2/FiO2 ratio increased by 45% after alveolar RM. The PaO2/FiO2 ratio reached a peak 60 minutes after alveolar RM. The PaCO2 increased by 51.9 mmHg after alveolar RM. The mean blood pressure was not affected by alveolar RM. There were no complications due to pressure injuries such as a pneumothorax, pneumomediastinum, and subcutaneous emphysema. CONCLUSION: In this study, alveolar RM using PCV improved the level of oxygenation in patients with an acute lung injury and acute respiratory distress syndrome. Moreover, there were no significant complications due to hemodynamic changes and pressure injuries. Therefore, alveolar RM using PCV can be applied easily and safely in clinical practice with lung protective strategy in early ALI and ARDS patients.