Volume-controlled mechanical ventilation

Pressure Limitation ◽

Controlled Mechanical Ventilation ◽

The goal of mechanical ventilation is to achieve adequate gas exchange while minimizing haemodynamic compromise and ventilator-associated lung injury. Volume-controlled ventilation can be delivered via several modes, including controlled mechanical ventilation, assist control (AC) and synchronized intermittent mandatory ventilation (SIMV). .In volume-controlled modes, the clinician sets the flow pattern, flow rate, trigger sensitivity, tidal volume, respiratory rate, positive end-expiratory pressure, and fraction of inspired oxygen. Patient ventilator synchrony can be enhanced by setting appropriate trigger sensitivity and inspiratory flow rate. I:E ratio can be adjusted to improve oxygenation, avoid air trapping and enhance patient comfort. There is little data regarding the benefits of one volume-controlled mode over another. In acute respiratory distress syndrome, low tidal volume ventilation in conjunction with plateau pressure limitation should be employed as there is a reduction in mortality with this strategy. This chapter addresses respiratory mechanics, modes and settings, clinical applications, and limitations of volume-controlled ventilation.

Effects of inspiratory flow on lung stress, pendelluft, and ventilation heterogeneity in ARDS: a physiological study

Critical Care ◽

10.1186/s13054-019-2641-0 ◽

2019 ◽

Vol 23 (1) ◽

Author(s):

Alessandro Santini ◽

Tommaso Mauri ◽

Francesca Dalla Corte ◽

Elena Spinelli ◽

Antonio Pesenti

Keyword(s):

Peep Level ◽

Transpulmonary Pressure ◽

Plateau Pressure ◽

Inspiratory Flow ◽

Absolute Difference ◽

Controlled Ventilation ◽

Ventilation Heterogeneity ◽

Volume Controlled ◽

Lung Stress

Abstract Background High inspiratory flow might damage the lungs by mechanisms not fully understood yet. We hypothesized that increasing inspiratory flow would increase lung stress, ventilation heterogeneity, and pendelluft in ARDS patients undergoing volume-controlled ventilation with constant tidal volume and that higher PEEP levels would reduce this phenomenon. Methods Ten ARDS patients were studied during protective volume-controlled ventilation. Three inspiratory flows (400, 800, and 1200 ml/s) and two PEEP levels (5 and 15 cmH2O) were applied in random order to each patient. Airway and esophageal pressures were recorded, end-inspiratory and end-expiratory holds were performed, and ventilation distribution was measured with electrical impedance tomography. Peak and plateau airway and transpulmonary pressures were recorded, together with the airway and transpulmonary pressure corresponding to the first point of zero end-inspiratory flow (P1). Ventilation heterogeneity was measured by the EIT-based global inhomogeneity (GI) index. Pendelluft was measured as the absolute difference between pixel-level inflation measured at plateau pressure minus P1. Results Plateau airway and transpulmonary pressure was not affected by inspiratory flow, while P1 increased at increasing inspiratory flow. The difference between P1 and plateau pressure was higher at higher flows at both PEEP levels (p < 0.001). While higher PEEP reduced heterogeneity of ventilation, higher inspiratory flow increased GI (p = 0.05), irrespective of the PEEP level. Finally, gas volume undergoing pendelluft was larger at higher inspiratory flow (p < 0.001), while PEEP had no effect. Conclusions The present exploratory analysis suggests that higher inspiratory flow increases additional inspiratory pressure, heterogeneity of ventilation, and pendelluft while PEEP has negligible effects on these flow-dependent phenomena. The clinical significance of these findings needs to be further clarified.

Comparison Between Volume Controlled Ventilation And Pressure Controlled Ventilation In Morbidly Obese Patients Undergoing Laparoscopic Gastric sleeve Surgery

QJM ◽

10.1093/qjmed/hcaa039.068 ◽

2020 ◽

Vol 113 (Supplement_1) ◽

Author(s):

M A Elshafie ◽

D M A Elfawy ◽

A A Abdelhak ◽

Y N Abdelalim

Keyword(s):

Mechanical Ventilation ◽

Obese Patients ◽

Gastric Sleeve ◽

Controlled Ventilation ◽

Ventilation Setting ◽

Gastric Sleeve Surgery ◽

Volume Controlled ◽

Abstract Background Although numerous studies conducted in the past years, there is no superior guideline that indicates the best ventilation mode during laparoscopic anesthesia inobese patients. There are numerous studies with dissimilar controversial points. The management of oxygenation in a morbid obese patient undergoing laparoscopic procedures presents many challenging aspects to the anesthetist. Objective The aim of this study was to equate the effect of pressure controlled ventilation (PCV) vs. volume controlled ventilation (VCV) on respiratory, oxygenation parameters and post operative complications. Patients and Methods This study was conducted on 80 patients who underwent laparoscopic gastric sleeve surgery in Ain Shams University Hospitals. Post induction of Anesthesia, Patients were divided into two groups. The first group mechanical ventilation setting was volume controlled ventilation and the second group mechanical ventilation setting was pressure controlled ventilation. Results The results of our study shows that despite some valuable effects regarding plateau and mean airway pressure with PCV, there is no momentous clinical difference between volume controlled ventilation (VCV) and pressure controlled ventilation (PCV) in obese patients undergoing laparoscopic gastric sleeve surgery. However, pressure controlled ventilation shows slightly more favorable results regarding post extubation oxygen saturation and the decrease of post operative basal atelectasis. It appears that using dual modes would be an epitome approach with lower complications and similar outcomes.

Effects of PEEP on Hemodynamic Variables of Pigs Submitted to Volume-controlled Ventilation under Pneumoperitoneum associated to Cephalodeclive

Acta Scientiae Veterinariae ◽

10.22456/1679-9216.113720 ◽

2021 ◽

Vol 49 ◽

Author(s):

Cléber Kazuo Ido ◽

Newton Nunes

Keyword(s):

Mechanical Ventilation ◽

Cardiac Output ◽

Intrathoracic Pressure ◽

The Other ◽

Abdominal Pressure ◽

Controlled Ventilation ◽

Hemodynamic Variables ◽

Background: Videolaparoscopic procedures have gained prominence due to their low invasiveness, causing less surgical trauma and better post-surgical recovery. However, the increase in intra-abdominal pressure due to the institution of pneumoperitoneum can alter the patient's homeostasis. Therefore, volume-controlled ventilation, associated with positive end-expiratory pressure (PEEP), improves arterial oxygenation and prevents pulmonary collapse, but it can lead to important hemodynamic changes. The aim of this study was to evaluate, comparatively, the effects of positive end expiratory-pressure (PEEP) on hemodynamic variables of pigs submitted to volume-controlled ventilation, during pneumoperitoneum and maintained in head-down tilt and determine which PEEP value promotes greater stability on hemodynamic variables. Materials, Methods & Results: Twenty-four pigs were used, between 55 and 65-day-old, weighing between 15 and 25 kg, randomly divided into 3 distinct groups differentiated by positive end-expiratory pressure: PEEP 0 (volume-controlled ventilation and PEEP of 0 cmH2O), PEEP 5 (volume-controlled ventilation and PEEP of 5 cmH2O) and PEEP 10 (volume-controlled ventilation and PEEP of 10 cmH2O). Volume-controlled ventilation was adjusted to 8 mL/kg of tidal volume and a respiratory rate of 25 movements per min. Anesthesia was maintained with continuous infusion of propofol (0.2 mg/kg/min) and midazolam (1 mg/kg/h). Pneumoperitoneum was performed with carbon dioxide (CO2), keeping the intra-abdominal pressure at 15 mmHg and the animals were positioned on a 30° head-down tilt. The evaluations of hemodynamic variables started 30 min after induction of anesthesia (M0), followed by measurements at 15-min intervals (from M15 to M90), completing a total of 7 evaluations. The variables of interest were collected over 90 min and submitted to analysis of variance followed by Tukey´s post-hoc test, with P < 0.05. The PEEP 10 group had higher values of CVP and mCPP, while the PEEP 5 group, mPAP and PVR were higher. The PEEP 0 group, on the other hand, had higher means of CI. Regarding the moments, there were differences in HR, SAP, DAP, MAP, CO, IC and TPR.Discussion: According to the literature, important hemodynamic effects due to pneumoperitoneum are reported, which can be caused by the pressure used in abdominal insufflation, CO2 accumulation, duration of the surgical procedure, hydration status and patient positioning. Mechanical ventilation associated with PEEP can also cause an increase in intrathoracic pressure and, therefore, reduce cardiac output. Cardiovascular changes are proportional to the PEEP used. Central venous pressure (PVC) measure the patient's preload, and intrathoracic pressure can interfere with this parameter. The peak pressure values in the PEEP 10 group were higher than the other groups, demonstrating that the increase in intrathoracic pressure results in higher PVC values. Regarding PAPm and PCPm, these variables can be influenced according to the PEEP values and the patient's position. In relation to CI, the increase in PEEP may reflect on intrathoracic pressure, resulting in greater compression of the heart, with a consequent reduction in cardiac output and cardiac index. Therefore, it is concluded that the PEEP effects of 0 cmH2O and 5 cmH2O on hemodynamics are discrete, under the proposed conditions. Keywords: mechanical ventilation, PEEP, head-down tilt, VCV, swine. Descritores: ventilação mecânica, PEEP, posição de Trendelenburg, suínos.

Combined Ventilation Of Two Subjects With A Single Mechanical Ventilator Using A New Medical Device: An In Vitro Study

10.1101/2021.01.06.425652 ◽

2021 ◽

Author(s):

Ignacio Lugones ◽

Matias Ramos ◽

Maria Fernanda Biancolini ◽

Roberto Eduardo Orofino Giambastiani

Keyword(s):

Tidal Volume ◽

Lung Compliance ◽

Controlled Ventilation ◽

Ventilation Modes ◽

The Subject ◽

Volume Controlled ◽

INTRODUCTION: The SARS-CoV2 pandemic has created a sudden lack of ventilators. DuplicAR® is a novel device that allows simultaneous and independent ventilation of two subjects with a single ventilator. The aims of this study are: a) to determine the efficacy of DuplicAR® to independently regulate the peak and positive-end expiratory pressures in each subject, both under pressure-controlled ventilation and volume-controlled ventilation, and b) to determine the ventilation mode in which DuplicAR® presents the best performance and safety. MATERIALS AND METHODS: Two test lungs are connected to a single ventilator using DuplicAR®. Three experimental stages are established: 1) two identical subjects, 2) two subjects with the same weight but different lung compliance, and 3) two subjects with different weight and lung compliance. In each stage, the test lungs are ventilated in two ventilation modes. The positive-end expiratory pressure requirements are increased successively in one of the subjects. The goal is to achieve a tidal volume of 7 ml/kg for each subject in all different stages through manipulation of the ventilator and the DuplicAR® controllers. RESULTS: DuplicAR® allows adequate ventilation of two subjects with different weight and/or lung compliance and/or PEEP requirements. This is achieved by adjusting the total tidal volume for both subjects (in volume-controlled ventilation) or the highest peak pressure needed (in pressure-controlled ventilation) along with the basal positive-end expiratory pressure on the ventilator, and simultaneously manipulating the DuplicAR® controllers to decrease the tidal volume or the peak pressure in the subject that needs less and/or to increase the positive-end expiratory pressure in the subject that needs more. While ventilatory goals can be achieved in any of the ventilation modes, DuplicAR® performs better in pressure-controlled ventilation, as changes experienced in the variables of one subject do not modify the other one. CONCLUSIONS: DuplicAR® is an effective tool to manage the peak inspiratory pressure and the positive-end expiratory pressure independently in two subjects connected to a single ventilator. The driving pressure can be adjusted to meet the requirements of subjects with different weight and lung compliance. Pressure-controlled ventilation has advantages over volume-controlled ventilation and is therefore the recommended ventilation mode.

Delivery of tidal volume from four anaesthesia ventilators during volume-controlled ventilation: a bench study †

British Journal of Anaesthesia ◽

10.1093/bja/aes594 ◽

2013 ◽

Vol 110 (6) ◽

pp. 1045-1051 ◽

Cited By ~ 14

Author(s):

G. Wallon ◽

A. Bonnet ◽

C. Guérin

Keyword(s):

Tidal Volume ◽

Controlled Ventilation ◽

Bench Study ◽

Effect of Ventilatory Settings on Accuracy of Cardiac Output Measurement Using Partial CO2Rebreathing

Anesthesiology ◽

10.1097/00000542-200201000-00021 ◽

2002 ◽

Vol 96 (1) ◽

pp. 96-102 ◽

Cited By ~ 40

Author(s):

Kazuya Tachibana ◽

Hideaki Imanaka ◽

Hiroshi Miyano ◽

Muneyuki Takeuchi ◽

Keiji Kumon ◽

...

Keyword(s):

Cardiac Output ◽

Tidal Volume ◽

Limits Of Agreement ◽

Ventilatory Mode ◽

Controlled Ventilation ◽

Volume Controlled ◽

Background Recently, a new device has been developed to measure cardiac output noninvasively using partial carbon dioxide (CO(2)) rebreathing. Because this technique uses CO(2) rebreathing, the authors suspected that ventilatory settings, such as tidal volume and ventilatory mode, would affect its accuracy: they conducted this study to investigate which parameters affect the accuracy of the measurement. Methods The authors enrolled 25 pharmacologically paralyzed adult post-cardiac surgery patients. They applied six ventilatory settings in random order: (1) volume-controlled ventilation with inspired tidal volume (V(T)) of 12 ml/kg; (2) volume-controlled ventilation with V(T) of 6 ml/kg; (3) pressure-controlled ventilation with V(T) of 12 ml/kg; (4) pressure-controlled ventilation with V(T) of 6 ml/kg; (5) inspired oxygen fraction of 1.0; and (6) high positive end-expiratory pressure. Then, they changed the maximum or minimum length of rebreathing loop with V(T) set at 12 ml/kg. After establishing steady-state conditions (15 min), they measured cardiac output using CO(2) rebreathing and thermodilution via a pulmonary artery catheter. Finally, they repeated the measurements during pressure support ventilation, when the patients had restored spontaneous breathing. The correlation between two methods was evaluated with linear regression and Bland-Altman analysis. Results When VT was set at 12 ml/kg, cardiac output with the CO(2) rebreathing technique correlated moderately with that measured by thermodilution (y = 1.02x, R = 0.63; bias, 0.28 l/min; limits of agreement, -1.78 to +2.34 l/min), regardless of ventilatory mode, oxygen concentration, or positive end-expiratory pressure. However, at a lower VT of 6 ml/kg, the CO(2) rebreathing technique underestimated cardiac out-put compared with thermodilution (y = 0.70x; R = 0.70; bias, -1.66 l/min; limits of agreement, -3.90 to +0.58 l/min). When the loop was fully retracted, the CO(2) rebreathing technique overestimated cardiac output. Conclusions Although cardiac output was underreported at small VT values, cardiac output measured by the CO(2) rebreathing technique correlates fairly with that measured by the thermodilution method.

Combined Ventilation of Two Subjects with a Single Mechanical Ventilator Using a New Medical Device: An In Vitro Study

Anesthesiology Research and Practice ◽

10.1155/2021/6691591 ◽

2021 ◽

Vol 2021 ◽

pp. 1-7

Author(s):

Ignacio Lugones ◽

Matías Ramos ◽

María Fernanda Biancolini ◽

Roberto Orofino Giambastiani

Keyword(s):

Tidal Volume ◽

Ventilation Mode ◽

Controlled Ventilation ◽

Ventilation Modes ◽

The Subject ◽

Volume Controlled ◽

Introduction. The SARS-CoV-2 pandemic has created a sudden lack of ventilators. DuplicARⓇ is a novel device that allows simultaneous and independent ventilation of two subjects with a single ventilator. The aims of this study are (a) to determine the efficacy of DuplicARⓇ to independently regulate the peak and positive-end expiratory pressures in each subject, both under pressure-controlled ventilation and volume-controlled ventilation and (b) to determine the ventilation mode in which DuplicARⓇ presents the best performance and safety. Materials and Methods. Two test lungs are connected to a single ventilator using DuplicARⓇ. Three experimental stages are established: (1) two identical subjects, (2) two subjects with the same weight but different lung compliance, and (3) two subjects with different weights and lung compliances. In each stage, the test lungs are ventilated in two ventilation modes. The positive-end expiratory pressure requirements are increased successively in one of the subjects. The goal is to achieve a tidal volume of 7 ml/kg for each subject in all different stages through manipulation of the ventilator and the DuplicARⓇ controllers. Results. DuplicARⓇ allows adequate ventilation of two subjects with different weights and/or lung compliances and/or PEEP requirements. This is achieved by adjusting the total tidal volume for both subjects (in volume-controlled ventilation) or the highest peak pressure needed (in pressure-controlled ventilation) along with the basal positive-end expiratory pressure on the ventilator and simultaneously manipulating the DuplicARⓇ controllers to decrease the tidal volume or the peak pressure in the subject that needs less and/or to increase the positive-end expiratory pressure in the subject that needs more. While ventilatory goals can be achieved in any of the ventilation modes, DuplicARⓇ performs better in pressure-controlled ventilation, as changes experienced in the variables of one subject do not modify the other one. Conclusions. DuplicARⓇ is an effective tool to manage the peak inspiratory pressure and the positive-end expiratory pressure independently in two subjects connected to a single ventilator. The driving pressure can be adjusted to meet the requirements of subjects with different weights and lung compliances. Pressure-controlled ventilation has advantages over volume-controlled ventilation and is therefore the recommended ventilation mode.

Correction to the paper ‘Delivery of tidal volume from four anaesthesia ventilators during volume-controlled ventilation: a bench study’

British Journal of Anaesthesia ◽

10.1093/bja/aew083 ◽

2016 ◽

Vol 116 (5) ◽

pp. 720-721 ◽

Cited By ~ 1

Author(s):

M Hallbäck ◽

M.K.E.B. Wallin

Keyword(s):

Tidal Volume ◽

Controlled Ventilation ◽

Bench Study ◽

Comparison of pressure- and volume-controlled ventilation during laparoscopic colectomy in patients with colorectal cancer

Scientific Reports ◽

10.1038/s41598-019-53503-9 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Sangbong Choi ◽

So Young Yang ◽

Geun Joo Choi ◽

Beom Gyu Kim ◽

Hyun Kang

Keyword(s):

Colorectal Cancer ◽

Mechanical Ventilation ◽

Laparoscopic Colectomy ◽

Supine Position ◽

Airway Pressure ◽

Respiratory Complications ◽

Controlled Ventilation ◽

Postoperative Respiratory Complications ◽

AbstractThis study investigated the differences in airway mechanics and postoperative respiratory complications using two mechanical ventilation modalities and the relationship between biomarkers and postoperative respiratory complications in patients with colorectal cancer who underwent laparoscopic colectomy. Forty-six patients with colorectal cancer scheduled for laparoscopic colectomy were randomly allocated to receive mechanical ventilation using either volume-controlled ventilation (VCV) (n = 23) or pressure-controlled ventilation (PCV) (n = 23). Respiratory parameters were measured and plasma sRAGE and S100A12 were collected 20 minutes after the induction of anesthesia in the supine position without pneumoperitoneum (T1), 40 minutes after 30° Trendelenburg position with pneumoperitoneum (T2), at skin closure in the supine position (T3), and 24 hours after the operation (T4). The peak airway pressure (Ppeak) at T2 was lower in the PCV group than in the VCV group. The plateau airway pressures (Pplat) at T2 and T3 were higher in the VCV group than in the PCV group. Plasma levels of sRAGE at T2 and T3 were 1.6- and 1.4-fold higher in the VCV group than in the PCV group, while plasma S100A12 levels were 2.6- and 2.2-fold higher in the VCV group than in the PCV group, respectively. There were significant correlations between Ppeak and sRAGE, and between Ppeak and S100A12. There were also correlations between Pplat and sRAGE, and between Pplat and S100A12. sRAGE and S100A12 levels at T2 and T3 showed high sensitivity and specificity for postoperative respiratory complications. Postoperative respiratory complications were 3-fold higher in the VCV group than in the PCV group. In conclusion, during laparoscopic colectomy in patients with colorectal cancer, the peak airway pressure, the incidence of postoperative respiratory complications, and plasma sRAGE and S100A12 levels were lower in the PCV group than in the VCV group. Intra- and postoperative plasma sRAGE and S100A12 were useful for predicting the development of postoperative respiratory complications.