scholarly journals Changes in dead space components during pressure-controlled inverse ratio ventilation: A secondary analysis of a randomized trial

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258504
Author(s):  
Go Hirabayashi ◽  
Yuuki Yokose ◽  
Kohei Nagata ◽  
Hiroyuki Oshika ◽  
Minami Saito ◽  
...  
Keyword(s):  
Dead Space ◽  
Controlled Trial ◽  
Secondary Analysis ◽  
Control Ventilation ◽  
Volume Control ◽  
Rank Test ◽  
Inverse Ratio Ventilation ◽  
Physiological Dead Space ◽  
Volume Control Ventilation ◽  
Pressure Controlled

Background We previously reported that there were no differences between the lung-protective actions of pressure-controlled inverse ratio ventilation and volume control ventilation based on the changes in serum cytokine levels. Dead space represents a ventilation-perfusion mismatch, and can enable us to understand the heterogeneity and elapsed time changes in ventilation-perfusion mismatch. Methods This study was a secondary analysis of a randomized controlled trial of patients who underwent robot-assisted laparoscopic radical prostatectomy. The inspiratory to expiratory ratio was adjusted individually by observing the expiratory flow-time wave in the pressure-controlled inverse ratio ventilation group (n = 14) and was set to 1:2 in the volume-control ventilation group (n = 13). Using volumetric capnography, the physiological dead space was divided into three dead space components: airway, alveolar, and shunt dead space. The influence of pressure-controlled inverse ratio ventilation and time factor on the changes in each dead space component rate was analyzed using the Mann-Whitney U test and Wilcoxon’s signed rank test. Results The physiological dead space and shunt dead space rate were decreased in the pressure-controlled inverse ratio ventilation group compared with those in the volume control ventilation group (p < 0.001 and p = 0.003, respectively), and both dead space rates increased with time in both groups. The airway dead space rate increased with time, but the difference between the groups was not significant. There were no significant changes in the alveolar dead space rate. Conclusions Pressure-controlled inverse ratio ventilation reduced the physiological dead space rate, suggesting an improvement in the total ventilation/perfusion mismatch due to improved inflation of the alveoli affected by heterogeneous expansion disorder without hyperinflation of the normal alveoli. However, the shunt dead space rate increased with time, suggesting that atelectasis developed with time in both groups.

Toilet bronchoscopy in the ICU

2016 ◽  
Author(s):  
Gianluigi Li Bassi ◽  
Carles Agusti
Keyword(s):  
Critically Ill ◽  
Critically Ill Patients ◽  
Control Ventilation ◽  
Volume Control ◽  
Non Invasive ◽  
Non Invasive Ventilation ◽  
Volume Control Ventilation ◽  
Baseline Values ◽  
Topical Anaesthetics ◽  
Pressure Controlled

Critically-ill patients retain respiratory secretions. Toilet bronchoscopy is applied to aspirate retained secretions and revert lung atelectasis. Toilet bronchoscopy is particularly indicated when retained secretions are visible during the procedureand air-bronchograms are not present at the chest radiograph. Yet, toilet bronchoscopy should only be applied when other less invasive methods of secretion removal have failed. Ventilatory settings during the intervention, the inspiratory fraction of oxygen should be increased to 100%. In volume control ventilation, the pressure limit alarm needs to be increased; during pressure-controlled ventilation, the set inspiratory pressure should be increased. The external PEEP should be decreased to at least 50% of the baseline values, to prevent barotrauma. The use of sedatives, analgesics, and topical anaesthetics is mandatory to achieve favourable procedural condition. Toilet bronchoscopy is also feasible and safe in critically-ill patients undergoing non-invasive ventilation.

scholarly journals Lung-protective properties of expiratory flow-initiated pressure-controlled inverse ratio ventilation: A randomised controlled trial

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243971
Author(s):  
Go Hirabayashi ◽  
Minami Saito ◽  
Sachiko Terayama ◽  
Yuki Akihisa ◽  
Koichi Maruyama ◽  
...  
Keyword(s):  
Forced Vital Capacity ◽  
Dead Space ◽  
Vital Capacity ◽  
Controlled Trial ◽  
Robot Assisted ◽  
Protective Properties ◽  
Physiological Dead Space ◽  
Expiratory Flow ◽  
Randomised Controlled ◽  
Pressure Controlled

Background Expiratory flow-initiated pressure-controlled inverse ratio ventilation (EF-initiated PC-IRV) reduces physiological dead space. We hypothesised that EF-initiated PC-IRV would be lung protective compared with volume-controlled ventilation (VCV). Methods Twenty-eight men undergoing robot-assisted laparoscopic radical prostatectomy were enrolled in this randomised controlled trial. The EF-initiated PC-IRV group (n = 14) used pressure-controlled ventilation with the volume guaranteed mode. The inspiratory to expiratory (I:E) ratio was individually adjusted by observing the expiratory flow-time wave. The VCV group (n = 14) used the volume control mode with a 1:2 I:E ratio. The Mann–Whitney U test was used to compare differences in the serum cytokine levels. Results There were no significant differences in serum IL-6 between the EF-initiated PC-IRV (median 34 pg ml-1 (IQR 20.5 to 63.5)) and VCV (31 pg ml-1 (24.5 to 59)) groups (P = 0.84). The physiological dead space rate (physiological dead space/expired tidal volume) was significantly reduced in the EF-initiated PC-IRV group as compared with that in the VCV group (0.31 ± 0.06 vs 0.4 ± 0.07; P<0.001). The physiological dead space rate was negatively correlated with the forced vital capacity (% predicted) in the VCV group (r = -0.85, P<0.001), but not in the EF-initiated PC-IRV group (r = 0.15, P = 0.62). Two patients in the VCV group had permissive hypercapnia with low forced vital capacity (% predicted). Conclusions There were no differences in the lung-protective properties between the two ventilatory strategies. However, EF-initiated PC-IRV reduced physiological dead space rate; thus, it may be useful for reducing the ventilatory volume that is necessary to maintain normocapnia in patients with low forced vital capacity (% predicted) during robot-assisted laparoscopic radical prostatectomy.

scholarly journals The Effect of Volume Controlled and Pressure Controlled Ventilation Modes on Cerebral Oximetry and Blood Gas Status in Laparoscopic Cholecystectomy, A Randomized Controlled Trial

2021 ◽  
Author(s):  
Emre Badur ◽  
Mustafa Altınay ◽  
Pınar Sayın ◽  
Ayşe Surhan Çınar ◽  
leyla türkoğlu ◽  
...  
Keyword(s):  
Laparoscopic Cholecystectomy ◽  
Pressure Control ◽  
Control Ventilation ◽  
Cerebral Oximetry ◽  
Volume Control ◽  
Pressure Control Ventilation ◽  
Ventilation Mode ◽  
Group V ◽  
Volume Control Ventilation ◽  
Ventilation Modes

Abstract Background: To compare the volume-controlled and pressure-controlled ventilation modes with near infrared spectroscopy (NIRS) cerebral oximetry and blood gas status in laparoscopic cholecystectomyMethods: Seventy patients (n=70), who underwent elective laparoscopic cholecystectomy operation were randomized into two groups (volume control ventilation - group V, pressure control ventilation - group P). Demographic data (age, gender, body mass index) and operative data (anesthesia, surgery, and insufflation durations) were recorded. Patients’ single derivation electrocardiogram, pulse oximetry, non-invasive arterial pressure, NIRS cerebral oximetry and end-tidal CO2 parameters were recorded. Measurements were done at the start of anesthesia (T0), at the end of intubation (T1), 5 minutes after the insufflation (T2), at the time just before desufflation (T3) and 5 minutes after desufflation (T4).The patients’ heart rate, systolic and diastolic arterial pressure, saturation of pulse oximetry, and NIRS values were recorded for time points. Additionally, arterial gas results and mechanical ventilation parameters were recorded as well. Results: No significant difference was found in age, sex, body mass index. Operation, anesthesia and insufflation durations were similar for the groups. In Group P, NIRS right T1-2-3 averages and NIRS left T2-3 averages were significantly higher than Group V (p=0.030, p=0.001, p=0.001, p=0.006, p=0.002 respectively). In Group P T1-T2-T4, mean peak pressures and mean plateau pressures were significantly lower than Group V (p=0.003, p=0.001, p<0.001, p=0.011, p=0.001, p<0.001 respectively).Conclusion: Mechanical ventilation that performed in pressure-control ventilation mode is resulted with better tissue oxygenation than volume-control ventilation mode. In pressure-control ventilation mode, peak pressure and plateau pressure were lower.Registration of study at ClinicalTrials.gov was made at 25/01/2021 with the NCT04723043 number.

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