Comparison of volume controlled ventilation and pressure controlled ventilation in patients undergoing robot-assisted pelvic surgeries: An open-label trial

Lung ultrasound score evaluation of the effect of pressure-controlled ventilation volume-guaranteed on patients undergoing laparoscopic-assisted radical gastrectomy

BACKGROUND

Laparoscopic-assisted radical gastrectomy (LARG) is the standard treatment for early-stage gastric carcinoma (GC). However, the negative impact of this procedure on respiratory function requires the optimized intraoperative management of patients in terms of ventilation.

AIM

To investigate the influence of pressure-controlled ventilation volume-guaranteed (PCV-VG) and volume-controlled ventilation (VCV) on blood gas analysis and pulmonary ventilation in patients undergoing LARG for GC based on the lung ultrasound score (LUS).

METHODS

The study included 103 patients with GC undergoing LARG from May 2020 to May 2023, with 52 cases undergoing PCV-VG (research group) and 51 cases undergoing VCV (control group). LUS were recorded at the time of entering the operating room (T0), 20 minutes after anesthesia with endotracheal intubation (T1), 30 minutes after artificial pneumoperitoneum (PP) establishment (T2), and 15 minutes after endotracheal tube removal (T5). For blood gas analysis, arterial partial pressure of oxygen (PaO2) and partial pressure of carbon dioxide (PaCO2) were observed. Peak airway pressure (Ppeak), plateau pressure (Pplat), mean airway pressure (Pmean), and dynamic pulmonary compliance (Cdyn) were recorded at T1 and T2, 1 hour after PP establishment (T3), and at the end of the operation (T4). Postoperative pulmonary complications (PPCs) were recorded. Pre- and postoperative serum interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) were measured by enzyme-linked immunosorbent assay.

RESULTS

Compared with those at T0, the whole, anterior, lateral, posterior, upper, lower, left, and right lung LUS of the research group were significantly reduced at T1, T2, and T5; in the control group, the LUS of the whole and partial lung regions (posterior, lower, and right lung) decreased significantly at T2, while at T5, the LUS of the whole and some regions (lateral, lower, and left lung) increased significantly. In comparison with the control group, the whole and regional LUS of the research group were reduced at T1, T2, and T5, with an increase in PaO2, decrease in PaCO2, reduction in Ppeak at T1 to T4, increase in Pmean and Cdyn, and decrease in Pplat at T4, all significant. The research group showed a significantly lower incidence of PPCs than the control group within 3 days postoperatively. Postoperative IL-1β, IL-6, and TNF-α significantly increased in both groups, with even higher levels in the control group.

CONCLUSION

LUS can indicate intraoperative non-uniformity and postural changes in pulmonary ventilation under PCV-VG and VCV. Under the lung protective ventilation strategy, the PCV-VG mode more significantly improved intraoperative lung ventilation in patients undergoing LARG for GC and reduced lung injury-related cytokine production, thereby alleviating lung injury.

Evaluation of the Effect of Pressure-Controlled Ventilation-Volume Guaranteed Mode vs. Volume-Controlled Ventilation Mode on Atelectasis in Patients Undergoing Laparoscopic Surgery: A Randomized Controlled Clinical Trial

Background and Objectives: Laparoscopic surgery, which results in less bleeding, less postoperative pain, and better cosmetic results, may affect the lung dynamics via the pneumoperitoneum. After laparoscopic surgery, atelectasis develops. The primary aim of the present study is to demonstrate the effects of two different ventilation modes on the development of atelectasis using lung ultrasound, and the secondary outcomes include the plateau pressure, peak inspiratory pressure, and compliance differences between the groups. Materials and Methods: In this study, 62 participants aged 18-75 years undergoing laparoscopic cholecystectomy were enrolled. The patients were randomly assigned into two groups: the volume-controlled ventilation (VCV) group (group V) or the pressure-controlled-volume guaranteed ventilation (PCV-VG) group (group PV). The lung ultrasound score (LUS) was obtained thrice: prior to induction (T1), upon the patient's initial arrival in the recovery room (T2), and just before departing the recovery unit (T3). The hemodynamic data and mechanical ventilation parameters were recorded at different times intraoperatively. Results: The LUS score was similar between the groups at all the times. The change in the LUS score of the right lower anterior chest was statistically higher in the VCV group than the PCV group. The peak inspiratory pressure (PIP) was found to be statistically higher in the V group than the PV group five minutes after induction (T5) (20.84 ± 4.32 p = 0.021). The plateau pressure was found to be higher in the V group than the PV group at all times (after induction (Tind) 17.29 ± 5.53 p = 0.004, (T5) 17.77 ± 4.89 p = 0.001, after pneumoperitoneum (TPP) 19.71 ± 4.28 p = 0.002). Compliance was found to be statistically higher in the PV group than the V group at all times ((Tind) 48.87 ± 15.37 p = 0.011, (T5) 47.94 ± 13.71 p = 0.043, (TPP) 35.65 ± 6.90 p = 0.004). Before and after the pneumoperitoneum, the compliance was determined to be lower in the V group than the PV group, respectively (40.68 ± 13.91 p = 0.043, 30.77 ± 5.73 p = 0.004). Conclusions: LUS score was similar between groups at all times. The PCV-VG mode was superior to the VCV mode in providing optimal ventilatory pressures and maintaining high dynamic compliance in patients undergoing laparoscopic abdominal surgery.

Ventilation strategy during urological and gynaecological robotic-assisted surgery: a narrative review

Robotic-assisted surgery has improved the precision and accuracy of surgical movements with subsequent improved outcomes. However, it requires steep Trendelenburg positioning combined with pneumoperitoneum that negatively affects respiratory mechanics and increases the risk of postoperative respiratory complications. This narrative review summarises the state of the art in ventilatory management of these patients in terms of levels of positive end-expiratory pressure (PEEP), tidal volume, recruitment manoeuvres, and ventilation modes during both urological and gynaecological robotic-assisted surgery. A review of the literature was conducted using PubMed/MEDLINE; after completing abstract and full-text review, 31 articles were included. Although different levels of PEEP were often evaluated within a protective ventilation strategy, including higher levels of PEEP, lower tidal volume, and recruitment manoeuvres vs a conventional ventilation strategy, we conclude that the best PEEP in terms of lung mechanics, gas exchange, and ventilation distribution has not been defined, but moderate PEEP levels (4-8 cm H2O) could be associated with better outcomes than lower or highest levels. Recruitment manoeuvres improved intraoperative arterial oxygenation, end-expiratory lung volume and the distribution of ventilation to dependent (dorsal) lung regions. Pressure-controlled compared with volume-controlled ventilation showed lower peak airway pressures with both higher compliance and higher carbon dioxide clearance. We propose directions to optimise ventilatory management during robotic surgery in light of the current evidence.

Correlation of arterial PaCO2 to end tidal CO2 in children undergoing laparoscopic abdominal surgery: An observational study

Background and Aims

The reliability of end tidal carbon dioxide (ETCO2) as a measure of arterial carbon dioxide (PaCO2) in pediatric laparoscopy is unclear. We evaluated the correlation of arterial to end tidal P(a-ET) CO2 during pediatric laparoscopy at two hours of pneumoperitoneum as the primary objective. We also compared P(a-ET) CO2 and alveolar to arterial oxygen gradient P(A-a) O2 and haemodynamics at fixed time points during surgery.

Material and Methods

A cross-sectional study was conducted in 25 children undergoing laparoscopic abdominal surgery. Arterial blood gases were drawn at T0, baseline, T10: ten minutes, T1h: 1 hour, T2h: 2 hours of pnuemoperitoneum and T 10d: 10 mins after deflation. The P(a-ET) CO2, P(A-a) O2, were measured from the blood gas and ETCO2 and FiO2 values on the monitor. The Pearson's correlation coefficient, the Wilcoxon rank test and Chi square test were used for statistical analysis.

Results

At T2h moderate correlation of P(a-ET) CO2 (r = 0.605, P = 0.001) with 40% children documenting accurate P(a-ET) CO2, -1 to +1 mm Hg was seen. Moderate correlation was also seen at T0, T10, T 10d but poor correlation at T 1h. The P(A-a) O2 increased progressively with surgery and did not correlate with P(a-ET) CO2. Heart rate was stable, but systolic blood pressures at T 10 and diastolic at T10, T 1h, T 2h were higher than baseline.

Conclusion

Moderate correlation was seen between PaCO2 and ETCO2 at 2 h of pnuemoperitoneum and at T0, T 10, and T 10d. P(A-a) O2 increased with surgery but did not correlate with P(a-ET) CO2.

Volume-controlled ventilation versus pressure-controlled ventilation during spine surgery in the prone position: A meta-analysis

Background

Many studies have investigated a comparison of the potency and safety of PCV versus VCV modes in spinal surgery in prone position. However, controversy about the maximal benefits of which ventilation modes remains. The main purpose of this meta-analysis was to investigate which one is the optimal ventilation for surgery patients undergoing spine surgery in prone position between the two ventilation modes as PCV and VCV.

Methods

We conducted a comprehensive search of PubMed, Embase, Web of Science, the Cochrane Library, and Google Scholar for potentially eligible articles. The continuous outcomes were analyzed using the mean difference and the associated 95% confidence interval. Meta-analysis was performed using Review Manager 5.4 software.

Results

Our meta-analysis included 8 RCTs involving a total of 454 patients between 2012 and 2020. The results demonstrated that IOB, Ppeak and CVP for VCV are significantly superior to PCV in spinal surgery in prone position. And PCV had higher Cdyn and PaO₂/FiO₂ than VCV. But there was no significant difference between PCV and VCV in terms of POB, Hb, HCT, HR and MAP.

Conclusions

The PCV mode displayed a more satisfying effect than VCV mode. Compared to VCV mode in same preset of tidal volume, the patients with PCV mode in prone position demonstrated less IOB, lower Ppeak and CVP, and higher PaO₂/FiO₂ in spinal surgery. However, there is no obvious difference between PCV and VCV in terms of hemodynamics variables (HR and MAP).

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The PCV mode displayed a more satisfying effect than VCV mode.

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Compared to VCV mode, the patients with PCV mode in prone position demonstrated less IOB, lower Ppeak and CVP, and higher PaO2/FiO2 in spinal surgery.

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There is no obvious difference between PCV and VCV in terms of hemodynamics variables.

The effect of steep head-down tilt on respiratory status in endometrial cancer patients with obesity during robot-assisted hysterectomy

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Robot-assisted surgery with a head-down tilt of 25° or below may be safe even in patients with morbid obesity.

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In patients with morbid obesity, a steep head-down tilt may present a risk of respiratory complications.

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A Trendelenburg position of 20–25° is adequate to perform robot-assisted surgery for endometrial cancer.

Objective

To evaluate the effect of head-down tilt on airway pressure in gynecologic patients with obesity during robot-assisted hysterectomy.

Methods

We retrospectively reviewed the records of 27 patients with body mass index (BMI) ≥ 25 kg/m² who underwent robot-assisted hysterectomy for endometrial cancer and endometrial atypical hyperplasia using the da Vinci Xi system. Mechanical ventilation was performed using pressure-controlled ventilation (PCV). Surgery was performed at 20° (group A, n = 17) or 25° head-down tilt (group B, n = 10). Respiratory parameters, including positive end-expiratory pressure (PEEP), tidal volume (TV), mean airway pressure (P mean), and peak airway pressure (P peak), were measured before (T1) and after the head-down tilt at 1 h (T2) and 2 h (T3) during anesthesia.

Results

The median BMI was 37.5 (range 28–51) kg/m², with no between-group variation. Oxygenation was maintained intraoperatively for all patients. The expiratory carbon dioxide partial pressure was 43.6 (95% confidence interval (CI) 42.2–45.0) mmHg. The P mean peak at T2 in group B was significantly higher than in group A (P < 0.011); however, other parameters at T2 and T3 did not differ significantly between the groups. Patients with BMI ≥ 40 kg/m² had significantly higher respiratory parameters than those with BMI < 40 kg/m². In patients with BMI ≥ 40 kg/m², the mean P means and P peaks at T3 were 17.3 cmH₂O (95% CI 16.3–18.3) and 29.4 cmH₂O (95% CI 27.1–31.7), respectively.

Discussion

With careful anesthetic management during PCV, robot-assisted surgery with a head-down tilt of 25° or below may be safe, even in patients with class III obesity.

The effect of different pressures of pneumoperitoneum on the dimensions of internal jugular vein – A prospective double-blind, randomised study

Background and Aims:

During laparoscopic surgeries, pneumoperitoneum increases intraabdominal pressure (IAP) which can increase the central venous pressure (CVP), and significant haemodynamic changes. In this study, we evaluated the effect of two different pressures of pneumoperitoneum, standard (13-15 mmHg), and low (6-8 mmHg) on the cross-sectional area (CSA) of the internal jugular vein (IJV) using ultrasonography, haemodynamic changes and duration of surgery. Surgeon’s comfort and feasibility of performing laparoscopic surgeries with low pressure pneumoperitoneum was also studied.

Methods:

This prospective, double-blind, randomised study included 148 patients of American Society of Anesthesiologists physical status class I and II undergoing laparoscopic surgeries. They were allocated into two groups: group S (standard) (number (n) = 73) had the IAP maintained between 13-15 mmHg; group L (low) had an IAP of 6-8 mmHg (n = 75). CSA of right IJV was measured before induction of anaesthesia (T1), 5 min after intubation (T2), 5 min after pneumoperitoneum (T3), before desufflation (T4) and 5 min prior to extubation (T5). Chi-square test, and Student’s paired and unpaired t test were used for statistical analysis.

Results:

The increase in IJV CSA at T3 when compared to T2 was statistically significant in both the groups (P < 0.001). On desufflation, the change in IJV CSA showed significant decrease in T5 value than T4 value in both the groups (P < 0.001). However, the percentage change in the IJV CSA was more in group S (35.4%) than group L (21.2%).

Conclusion:

CSA of IJV increased significantly even with lower IAP of 6-8 mmHg. Laparoscopic surgery can be performed conveniently even at low IAP.

Effects of ventilation mode type on intra-abdominal pressure and intra-operative blood loss in patients undergoing lumbar spine surgery: A randomised clinical study

BACKGROUND AND AIMS

The aim of the study was to evaluate the effect of mode of mechanical ventilation; pressure-controlled ventilation (PCV) vs. volume-controlled ventilation (VCV) on airway pressures, intra-abdominal pressure (IAP) and intra-operative surgical bleeding in patients undergoing lumbar spine surgery.

METHODS

This was a prospective, randomised study that included 50 American Society of Anesthesiologists class I and II patients undergoing lumbar spine surgery who were mechanically ventilated using PCV or VCV mode. The respiratory parameters (peak and plateau pressures) and IAP were measured after anaesthesia induction in supine position, 10 min after the patients were changed from supine to prone position, at the end of the surgery in prone position, and after the patients were changed from prone to supine position. The amount of intraoperative surgical bleeding was measured by objective and subjective methods.

RESULTS

The primary outcome was the amount of intraoperative surgical bleeding. It was significantly less in the PCV group than in the VCV group (137 ± 24.37 mL vs. 311 ± 66.98 mL) (P = 0.000). Similarly, on comparing other parameters like peak inspiratory pressures, plateaupressures and IAP, the patients in PCV group had significantly lower parameters than those in VCV group (P < 0.05). No harmful events were recorded.

CONCLUSION

In patie,nts undergoing lumbar spine surgery, use of PCV mode decreased intraoperative surgical bleeding, which may be related to lower intraoperative respiratory pressures and IAP.

Effect of ultrasound-guided-pressure-controlled ventilation on intraoperative blood gas and ventilatory parameters during thoracic surgery

Background and Aims:

Identifying an ideal intraoperative ventilation strategy remains an area of research. We evaluated the effect of ultrasound-guided–pressure-controlled ventilation (UG-PCV) on the blood-gas and ventilatory parameters, during both two-lung ventilation (TLV) and one-lung ventilation (OLV) for thoracic surgery of unilateral pulmonary disease, compared with volume-targeted PCV (VT-PCV).

Methods:

In a prospective, parallel-group and double-blinded design, 40 consecutive patients were randomised into two groups. Group A: Received VT-PCV at a tidal volume (TV) of 9 mL/kg for TLV and 5 mL/kg for OLV; group B: Received UG-PCV at an inspiratory pressure (2 cmH₂O increments every 15 s) targeted to achieve the alveolar aeration at the base of the dependent lung (ultrasound-guided), for both TLV/OLV, respectively. Primary outcome included arterial oxygen partial pressure (PaO₂) measured at baseline before anaesthesia induction (T1), at 30 min immediately before conversion from TLV to OLV (T2), at 30 min on OLV (T3) and before terminating OLV at the end of surgery (T4). Statistical tool included Mann-Whitney test.

Results:

The PaO₂ (mmHg) was significantly higher in group B (374.5 ± 25.9, 321.7 ± 35.2 and 357.0 ± 24.7) as compared to group A (353.3 ± 38.1, 272.6 ± 37.9 and 295.3 ± 40.1), at T2, T3 and T4, respectively. The acid-base status remained preserved in group B, while gradual respiratory acidosis was observed in group A. The bicarbonate levels remained uniform in all patients. The TV and airway pressures were marginally higher in group B, with no intraoperative complications.

Conclusion:

The UG-PCV mode offered better oxygenation, homogenous acid-base balance and individualised alveolar ventilation for thoracic surgery.

Comparison of effects of volume-controlled and pressure-controlled mode of ventilation on endotracheal cuff pressure and respiratory mechanics in laparoscopic cholecystectomies: A randomised controlled trial

Background and Aims:

One of the pathophysiological consequences of pneumoperitoneum is variations in endotracheal cuff pressure (ETTc). Volume-controlled mode and pressure-controlled mode of ventilation being two modes of ventilatory strategies; we intended to find out variations in ETTc governed by respiratory mechanics between these two modes during laparoscopic cholecystectomies.

Methods:

After obtaining ethics committee approval, this randomised (1:1), active-controlled, parallel-assigned study was done on 60 patients undergoing laparoscopic cholecystectomies. These patients were allocated into two groups by computer-generated randomisation: Volume-controlled mode (V) and pressure-controlled mode (P). We observed for variations in ETTc which was the primary aim and haemodynamic parameters; respiratory mechanics at baseline (T1), at pneumoperitoneum (T2), after 10 min (T3), 20 min (T4) of pneumoperitoneum and at desufflation (T5). Post-operative laryngotracheal co-morbidities were also observed. Analysis was done using Statistical Package for the Social Sciences version 16.0 (IBM SPSS Statistics, Somers NY, USA).

Results:

No statistically significant difference was found in both groups either concerning ETTc, haemodynamic parameters or complications. In both groups, ETTc variation was statistically significant when compared from baseline to desufflation (T1 versus T5) and in group V additionally from baseline to time of pneumoperitoneum (T1 versus T2). Group P showed lower peak airway pressure at desufflation and higher mean airway pressure throughout at all the time intervals.

Conclusions:

There is no variation in ETTc between the two modes. Group P appears to be better in terms of lower Ppeak and better Pmean.

Lung ultrasound score-based perioperative assessment of pressure-controlled ventilation-volume guaranteed or volume-controlled ventilation in geriatrics: a prospective randomized controlled trial

Purpose

Recent studies have shown the potential benefits of pressure-controlled ventilation-volume guaranteed (PCV-VG) compared to volume-controlled ventilation (VCV), but the results were not impressive. We assessed the effects of PCV-VG versus VCV in elderly patients by using lung ultrasound score (LUS).

Patients and methods

Elderly patients (aged 65-90 years) scheduled for hip joint surgery were randomly assigned to either the PCV-VG or VCV group during general anesthesia. LUS and mechanical ventilator parameters were evaluated before induction, 30 mins after a semi-lateral position change, during supine repositioning before awakening, and 15 mins after arrival to the post-anesthesia care unit (PACU). Pulmonary function tests were performed before and after surgery. Other recovery indicators were also assessed in the PACU.

Results

A total of 76 patients (40 for PCV-VG and 36 for VCV) were included this study. Demographic data showed no significant difference between the two groups. In both groups, LUSs before induction were significantly lower than those at other time points. LUSs of the VCV group were significantly increased during perioperative periods compared with the PCV-VG group (p=0.049). Visualized LUS modeling suggested an intuitive difference in the two groups and unequal distribution in lung aeration. Higher dynamic compliance and lower inspiratory peak pressure were observed in the PVC-VG group compared to the VCV group (33.54 vs 27.36, p<0.001; 18.93 vs 21.19, p<0.001, respectively). Postoperative forced vital capacity of the VCV group was lower than that of PCV-VG group, but this result was not significant (2.06 vs 1.79, respectively; p=0.091). The other respiratory data are comparable between the two groups.

Conclusion

The PCV-VG group showed better LUS compared with the VCV group. Moreover, LUS modeling in both groups suggests non-homogeneous and positional change in lung aerations during surgery.

Clinical trial registration

This study was registered at the UMIN clinical trials registry (unique trial number: UMIN000029355; registration number: R000033510).

Pressure-controlled ventilation could decrease intraoperative blood loss and improve airway pressure measures during lumbar discectomy in the prone position: A comparison with volume-controlled ventilation mode

Background and Aims

Prone positioning may induce alterations of hemodynamic and airway pressure parameters that may affect intraoperative (IO) blood loss. Pressure-controlled ventilation (PCV) may modify these alterations. To observe the relation between ventilation mode and hemodynamic, airway pressure changes, and blood loss during lumbar discectomy performed in the prone position.

Material and Methods

Volume-controlled ventilation (VCV) patients were using tidal volume (TV) of 8-10 ml/Kg, but for pressure-controlled ventilation (PCV) patients peak inspiratory pressure (PIP) was adjusted to provide the same TV according to ideal body weight. Respiratory and hemodynamic parameters were recorded in supine (T1), on turning to prone (T2), and on returning to the supine position (T3). Primary outcome included amount of IO blood loss; Secondary outcome included need for blood transfusion, IO hemodynamics, and airway pressure changes.

Results

IO blood loss and central venous pressure (CVP) were significantly higher with VCV than PCV patients. Heart rate and blood pressure were significantly reduced in the prone position with little impact of ventilation mode. Prone positioning resulted in significant increase of P-peak and non-significant decrease of P-mean pressure with VCV, while with PCV resulted in a significantly increased airway pressures. P-peak pressure was significantly lower with PCV in supine and prone positions than VCV. P-mean pressure was significantly lower in supine but significantly higher in the prone position with PCV than VCV.

Conclusions

Prone positioning and VCV were associated with increased CVP and IO blood loss, while PCV could lessen these effects and significantly improve airway pressures.