Assessment of Perioperative Atelectasis Using Lung Ultrasonography in Patients Undergoing Pneumoperitoneum Surgery in the Trendelenburg Position: Aspects of Differences according to Ventilatory Mode

Intraoperative lung protection: strategies and their impact on outcomes

PURPOSE OF REVIEW

The present review summarizes the current knowledge and the barriers encountered when implementing tailoring lung-protective ventilation strategies to individual patients based on advanced monitoring systems.

RECENT FINDINGS

Lung-protective ventilation has become a pivotal component of perioperative care, aiming to enhance patient outcomes and reduce the incidence of postoperative pulmonary complications (PPCs). High-quality research has established the benefits of strategies such as low tidal volume ventilation and low driving pressures. Debate is still ongoing on the most suitable levels of positive end-expiratory pressure (PEEP) and the role of recruitment maneuvers. Adapting PEEP according to patient-specific factors offers potential benefits in maintaining ventilation distribution uniformity, especially in challenging scenarios like pneumoperitoneum and steep Trendelenburg positions. Advanced monitoring systems, which continuously assess patient responses and enable the fine-tuning of ventilation parameters, offer real-time data analytics to predict and prevent impending lung complications. However, their impact on postoperative outcomes, particularly PPCs, is an ongoing area of research.

SUMMARY

Refining protective lung ventilation is crucial to provide patients with the best possible care during surgery, reduce the incidence of PPCs, and improve their overall surgical journey.

Effects of pressure-controlled ventilation targeting end-inspiratory flow rate on pulmonary complications and inflammation levels in patients undergoing spinal surgery in the prone position: a randomized clinical trial

BACKGROUND

This study assessed the impact of pressure-controlled ventilation (PCV) focusing on end-inspiratory flow rate on the incidence of postoperative pulmonary complications (PPCs) and inflammation levels in patients undergoing spinal surgery in the prone position.

METHODS

A total of 187 patients who underwent posterior spinal surgery were enrolled and randomly divided into 3 groups: 61 in the volume-controlled ventilation (VCV) group (group V), 62 in the PCV-volume-guaranteed (VG) group (group P1), and 64 in the PCV-VG end-expiratory zero flow rate group (group P2). Indicators including tidal volume (VT), peak airway pressure (Ppeak), and dynamic lung compliance (Cdyn) were recorded. The Ppeak, Cdyn, PETCO2, and oxygenation index (PaO2/FiO2) after intubation (T0), after prone position (T1), 60 min after prone position (T2), and after supine position at the end of surgery (T3) of the three groups were collected.

RESULTS

In the within-group comparison, compared with T0, Ppeak increased at T1 - 2 in groups V and P1 (P < 0.01), whereas it decreased at T1 - 3 in group P2 (P < 0.01). Cdyn decreased at T1 - 2 and PaO2/FiO2 increased at T1 - 3 in all three groups (P < 0.01), and PaO2/FiO2 increased at T1 - 3 (P < 0.01). Compared with group V, Ppeak decreased at T0 - 3 in group P1 (P < 0.01) and at T1 - 3 in group P2 (P < 0.01), while Cdyn increased at T0 - 3 in groups P1 and P2 (P < 0.01). Compared with group P1, Ppeak was elevated at T0 (P < 0.01) and decreased at T1 - 3 (P < 0.05), and Cdyn was elevated at T0 - 3 in group P2 (P < 0.01). The total incidence of PPCs in group P2 was lower than that in group V (P < 0.01). Compared with the preoperative period, serum interleukin 6 (IL-6) and C-reactive protein (CRP) levels were increased at 24 and 72 h after surgery in group V (P < 0.01), whereas that was increased at 24 h after surgery in group P1 and group P2 (P < 0.01). Compared with group V, serum IL-6 and CRP levels were reduced at 24 h after surgery in groups P1 and P2 (P < 0.01 or < 0.05).

CONCLUSION

In patients undergoing spinal surgery in the prone position, PCV-VG targeting an end-inspiratory zero flow rate lowers the incidence of PPCs and inflammation levels.

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.