Managing hypoxemia during minimally invasive thoracic surgery

Ultrasound-guided versus conventional lung recruitment manoeuvres in thoracic surgery: a randomised controlled study

Lung recruitment manoeuvres (RMs) during mechanical ventilation may reduce atelectasis, however, the optimal recruitment strategy for patients undergoing thoracic surgery remains unknown. Our study was designed to investigate whether ultrasound-guided lung RMs is superior to conventional RMs in reducing perioperative atelectasis during thoracic surgery with one-lung ventilation. We conducted a randomised controlled clinical trial from August 2022 to September 2022. Sixty patients scheduled for video-assisted thoracoscopic surgery (VATS) under general anaesthesia were enrolled. Subjects were randomly divided into the ultrasound-guided RMs group (manual inflation guided by lung ultrasound) or conventional RMs group (manual inflation with 30 cmH2O pressure). Lung ultrasound were performed at three predefined time points (1 min after anaesthetic induction; after RMs at the end of surgery; before discharge from postanesthesia care unit [PACU]). The primary outcome was lung ultrasound score before discharge from the PACU after extubation. In the early postoperative period, lung aeration deteriorated in both groups even after lung RMs. However, ultrasound-guided lung RMs had significantly lower lung ultrasound scores when compared with conventional RMs in bilateral lungs (2.0 [0.8-4.0] vs. 8.0 [3.8-10.3], P < 0.01) at the end of surgery, which remained before patients discharged from the PACU. Accordingly, the lower incidence of atelectasis was found in ultrasound-guided RMs group than in conventional RMs group (7% vs. 53%; P < 0.01) at the end of surgery. Ultrasound-guided RMs is superior to conventional RMs in improving lung aeration and reducing the incidence of lung atelectasis at early postoperative period in patients undergoing VATS. The study protocol was approved by the Institutional Review Board of the Fudan University Shanghai Cancer Center (No. 220,825,810; date of approval: August 5, 2022) and registered on Chinese Clinical Trial Registry (registration number: ChiCTR2200062761).

Application of Continuous Positive Airway Pressure During Video-Assisted Thoracoscopic Surgery

Purpose of Review

Video-assisted thoracoscopic surgery (VATS) and robotic-assisted thoracoscopic surgery (RATS) are used for anatomic resection of early stage cancer. These surgical techniques require the use of one-lung ventilation (OLV). During OLV, an obligatory intrapulmonary shunt may produce hypoxemia. One method to correct hypoxemia is with the use of continuous positive airway pressure (CPAP). This review focuses on 1) the lung physiology of OLV; 2) application of CPAP in VATS or RATS during supine and lateral position; and 3) the application of CPAP in COVID-19 patients during OLV.

Recent Findings

Studies have shown the beneficial effects of CPAP to improve oxygenation during OLV while the patient is in the lateral decubitus position. In contrast, studies have shown no benefit on improving oxygenation with CPAP in patients undergoing OLV in supine position.

Summary

The application of CPAP to the non-dependent lung is one of the options to treat hypoxemia during VATS or RATS.

Effects of prostaglandin E1 nebulization of ventilated lung under 60%O2 one lung ventilation on patients' oxygenation and oxidative stress: a randomised controlled trial

Background

High FiO₂ during one-lung ventilation (OLV) can improve oxygenation, but increase the risk of atelectasis and oxidative stress. The aim of this study was to analyze whether Prostaglandin E₁ (PGE₁) can improve oxygenation and attenuate oxidative stress during OLV under a lower FiO₂.

Method

Ninety patients selectively undergoing thoracotomy for esophageal cancer were randomly divided into three groups (n = 30/group): Group P (FiO₂ = 0.6, inhaling PGE₁ 0.1 μg/kg), Group L (FiO₂ = 0.6) and Group C (FiO₂ = 1.0). The primary outcomes were oxygenation and pulmonary shunt during OLV. Secondary outcomes included haemodynamics, respiratory mechanics and oxidative stress in serum.

Results

Patients in Group P had significantly higher PaO₂ and lower shunt fraction in 30 min of OLV compared with Group L. Compared with Group C, patients in Group P had similar levels of PaO₂/FiO₂ in 60 min and higher levels of PaO₂/FiO₂ at 2 h during OLV. The levels of PvO₂ and SvO₂ in Group P and Group L were significantly lower than Group C. Patients in Group P and Group L had significantly higher levels of superoxide dismutase and lower levels of malondialdehyde than Group C. No significant differences were found in SPO₂, ETCO₂, PaCO₂, Paw, HR and MAP among the three groups. The complications in Group C were significantly higher than another two groups.

Conclusion

PGE₁ can maintain adequate oxygenation in patients with low FiO₂ (0.6) during OLV. Reducing FiO₂ to 0.6 during OLV can decrease the levels of oxidative stress and complications after OLV.

Trial registration

chictr.org.cn identifier: ChiCTR1800017100.

Thoracoscopic partial lung resection following pneumonectomy: a report of three cases

Background

The prognosis of patients who undergo unilateral pneumonectomy and subsequently develop a contralateral pulmonary tumor can be improved by tumor resection. Thus, surgery is a treatment option if the patient’s pulmonary function and performance status are satisfactory. To date, there have been only few cases reporting thoracoscopic lung resection for pulmonary tumor after contralateral pneumonectomy because of the difficulty in respiratory management during surgery. Thoracoscopic surgery requires the maintenance of the operative field to allow the lung to collapse, and in partial lung resection we need to identify tumor localization. The identification of a tumor lesion just inferior to the pleura is easy; however, the identification of a tumor lesion in the deep parts is difficult. The tumor in the deep part of the lung segments can be easily located if the tumor-affected lobe is allowed to completely collapse. Therefore, ventilation technique should be modified according to the tumor localization.

Case presentation

Here, we report three cases of thoracoscopic partial lung resections for pulmonary tumors that developed after contralateral pneumonectomy. Intermittent manual ventilation using a tracheal tube was performed in two cases with a lesion just inferior of the pleura. The tumors in both patients were resected using automatic suturing devices while arresting manual ventilation. The affected lobe was allowed to collapse using a bronchial blocker in one of the cases with a lesion in the deep part. Furthermore, she had contralateral pneumothorax with bullae on the right upper and lower lobes of the lung. The tumor in the deep part of the lung segment and ruptured bullae were easily located and resected using automatic suturing devices. The hemodynamic status of the patients was stable, and the intra- and postoperative courses were uneventful.

Conclusions

Our cases demonstrate that thoracoscopic lung resection after contralateral pneumonectomy can be performed if intermittent manual ventilation is utilized when the tumor is located just inferior to the pleura and if selective double ventilation using an intrabronchial blocker is utilized when the tumor is located in the deep part.

One-Lung Ventilation with Additional Ipsilateral Ventilation of Low Tidal Volume and High Frequency in Lung Lobectomy

BACKGROUND To investigate the protective effects of additional ipsilateral ventilation of low tidal volume and high frequency on lung functions in the patients receiving lobectomy. MATERIAL AND METHODS Sixty patients receiving lung lobectomy were randomized into the conventional one-lung ventilation (CV) group (n=30) and the ipsilateral low tidal volume high frequency ventilation (LV) group (n=30). In the CV group, patients received only contralateral OLV. In the LV group, patients received contralateral ventilation and additional ipsilateral ventilation of low tidal volume of 1-2 ml/kg and high frequency of 40 times/min. Normal lung tissues were biopsied for the analysis of lung injury. Lung injury was scored by evaluating interstitial edema, alveolar edema, neutrophil infiltration, and alveolar congestion. RESULTS At 30 min and 60 min after the initiation of one-lung ventilation and after surgery, patients in the LV group showed significantly higher ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen than those in the CV group (P<0.001). Lung injury was significantly less severe (2.7±0.7) in the LV group than in the CV group (3.1±0.7) (P=0.006). CONCLUSIONS Additional ipsilateral ventilation of low tidal volume and high frequency can decrease the risk of hypoxemia and alleviate lung injury in patients receiving lobectomy.

Intraoperative crisis resource management during a non-intubated video-assisted thoracoscopic surgery

The management of surgical and medical intraoperative emergencies are included in the group of high acuity (high potential severity of an event and the patient impact) and low opportunity (the frequency in which the team is required to manage the event). This combination places the patient into a situation where medical errors could happen more frequently. Although medical error are ubiquitous and inevitable we should try to establish the necessary knowledge, skills and attitudes needed for effective team performance and to guide the development of a critical event. This strategy would probably reduce the incidence of error and improve decision-making. The way to apply it comes from the application of the management of critical events in the airline industry. Its use in a surgical environment is through the crisis resource management (CRM) principles. The CRM tries to develop all the non-technical skills necessary in a critical situation, but not only that, also includes all the tools needed to prevent them. The purpose of this special issue is to appraise and summarize the design, implementation, and efficacy of simulation-based CRM training programs for a specific surgery such as the non-intubated video-assisted thoracoscopic surgery.

Step-by-step clinical management of one-lung ventilation: continuing professional development

PURPOSE

The purpose of this Continuing Professional Development Module is to review the issues pertinent to one-lung ventilation (OLV) and to propose a management strategy for ventilation before, during, and after lung isolation.

PRINCIPAL FINDINGS

The need for optimal lung isolation has increased with the advent of video-assisted thoracoscopic surgery, as surgical exposure is critical for successful surgery. Continuous positive airway pressure applied to the operative lung or intermittent two-lung ventilation should therefore be avoided if possible. Optimal management of OLV should provide adequate oxygenation and also prevent acute lung injury (ALI), the leading cause of death following lung resection. Research conducted in the last decade suggests implementing a protective ventilation strategy during OLV that consists of small tidal volumes based on ideal body weight, routine use of positive end-expiratory pressure, low inspired oxygen fraction, with low peak and plateau airway pressures. High respiratory rates to compensate for low tidal volumes may predispose to significant air trapping during OLV, so permissive hypercapnea is routinely employed. The management of OLV extends into the period of two-lung ventilation, as the period prior to OLV impacts lung collapse, and both the time before and after OLV influence the extent of ALI. Lung re-expansion at the conclusion of OLV is an important component of ensuring adequate ventilation and oxygenation postoperatively but may be harmful to the lung.

CONCLUSIONS

Optimal perioperative care of the thoracic patient includes a protective ventilation strategy from intubation to extubation and into the immediate postoperative period. Anesthetic goals include the prevention of perioperative hypoxemia and postoperative ALI.