Effect of Switching between Pressure-controlled and Volume-controlled Ventilation on Respiratory Mechanics and Hemodynamics in Obese Patients during Abdominoplasty

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.

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.

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.