A Novel Method of Treating Hypoxemia During One-Lung Ventilation for Thoracoscopic Surgery

Continuous positive airway pressure combined with small-tidal-volume ventilation on arterial oxygenation and pulmonary shunt during one-lung ventilation in patients undergoing video-assisted thoracoscopic lobectomy: A randomized, controlled study

BACKGROUND

One-lung ventilation (OLV) is frequently applied during video-assisted thoracoscopic surgery (VATS) airway management to collapse and isolate the nondependent lung (NL). OLV can give rise to hypoxemia as a result of the pulmonary shunting produced. Our study aimed to assess the influence of continuous positive airway pressure (CPAP) combined with small-tidal-volume ventilation on improving arterial oxygenation and decreasing pulmonary shunt rate (QS/QT) without compromising surgical field exposure during OLV.

METHODS

Forty-eight patients undergoing scheduled VATS lobectomy were enrolled in this research and allocated into three groups at random: C group (conventional ventilation, no NL ventilation intervention was performed), LP group (NL was ventilated with lower CPAP [2 cmH2O] and a 40-60 mL tidal volume [TV]), and HP group (NL was ventilated with higher CPAP [5 cmH2O] and a 60-80 mL TV). Record the blood gas analysis data and calculate the QS/QT at the following time: at the beginning of the OLV (T0), 30 min after OLV (T1), and 60 min after OLV (T2). Surgeons blinded to ventilation techniques were invited to evaluate the surgical fields.

RESULTS

The demography data of the three groups were consistent with the surgical data. At T1, PaO2 in the HP group was substantially higher compared to the C group (P < 0.05), while there was no significant difference in the LP group (P > 0.05). At T1-T2, PaCO2 in the LP and HP groups was significantly less than that in the C group (P < 0.05). At T1, the QS/QT values of groups C, LP, and HP were 29.54 ± 6.89%, 22.66 ± 2.08%, and 19.64 ± 5.76%, respectively, and the QS/QT values in the LP and HP groups markedly reduced (P < 0.01). The surgical field's evaluation by the surgeon among the three groups was not notable (P > 0.05).

CONCLUSION

CPAP combined with small-tidal-volume ventilation effectively improved arterial oxygenation and reduced QS/QT and PaCO2 without compromising surgical field exposure during OLV. Among them, 5 cmH2O CPAP + 60-80 ml TV ventilation had a better effect on improving oxygenation.

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.

Comparison of High-Flow Humidified Oxygen With Conventional Continuous Positive Airway Pressure in Nonventilated Lungs During Thoracic Surgery: A Randomized Cross-Over Study

OBJECTIVE

This study assessed the efficacy of high-flow humidified oxygen (HFHO) as an alternative to continuous positive airway pressure (CPAP) for improving oxygenation while preserving nonventilated lung collapse during one-lung ventilation.

DESIGN

A prospective randomized cross-over trial.

SETTING

A tertiary medical center.

PARTICIPANTS

The study comprised 28 patients undergoing elective thoracotomy with one-lung ventilation using a double-lumen endobronchial tube placement.

INTERVENTIONS

The patients received prophylactic CPAP or HFHO to the nonventilated lung for 20 minutes and were then crossedover to the other oxygenation modality for 20 minutes, with a 20-minute recovery interval between the two modalities.

MEASUREMENTS AND MAIN RESULTS

Changes in respiratory parameters and lung deflation quality were recorded. Both CPAP and HFHO increased the partial pressure of arterial oxygen in either sequence in both groups, ranging from 31.8-to-66.0 mmHg. However, the increments from these two interventions were not statistically significant (95% confidence interval -12.84 to 21.87; p = 0.597). There were no differences in other parameters. Half the patients receiving CPAP experienced worsening of the surgical condition, whereas the HFHO patients experienced no change or reported a better lung deflation (p < 0.001).

CONCLUSION

HFHO could be an alternative method to CPAP for improving arterial oxygenation while preserving lung deflation during one-lung ventilation. However, additional studies are warranted in regard to its cost-effectiveness and establishment as a routine treatment.

Effects of bronchial blockers on one-lung ventilation in general anesthesia: A randomized controlled trail

BACKGROUND

Double-lumen bronchial tubes (DLBT) and bronchial blockers (BB) are commonly used in the anesthesia for clinical thoracic surgery. But there are few systematic clinical comparisons between them. In this study, the effects of BB and DLBT on one-lung ventilation (OLV) are studied.

METHODS

The 200 patients with thoracic tuberculosis undergoing thoracic surgery, were randomly assigned to group A (DLBT) and group B (BB). Intubation time, hemodynamic changes (mean arterial pressure [MAP], heart rate [HR]), and arterial blood gas indicators (arterial partial pressure of carbon dioxide [PaCO2], arterial partial pressure of oxygen [PaO2], airway plateau pressure [Pplat], and airway peak pressure [Ppeak]) at 4 time points were recorded. Complications such as hoarseness, pulmonary infection, pharyngalgia, and surgical success rate were also evaluated postoperatively.

RESULTS

Intubation times were shorter in group B. Both MAP and HR in group A were significantly higher 1 minute after intubation than before, but also higher than those in group B. PaO2 levels were lower in both groups during (OLV) than immediately after anesthesia and after two-lung ventilation (TLV), with PaO2 being lower after 60 minutes of OLV than after 20 minutes of OLV. Furthermore, at both points during OLV, PaO2 was lower in group A than in group B. No significant differences in PaCO2 were found between the 2 groups. Ppeak and Pplat were increased in both groups during OLV, with both being higher in group A than in group B. The incidence of postoperative hoarseness, pulmonary infection, and pharyngalgia were lower in group B. There was no significant difference in the success rate of operation between the 2 groups.

CONCLUSIONS

Compare with using DLBT, implementation of BB in general anesthesia has less impact on hemodynamics, PaO2 and airway pressures, and achieves lower incidence of postoperative complication.

Can apneic oxygen insufflation become a novel lung protective ventilation strategy? A randomized, controlled, blinded, single center clinical trial

Objective

The aim of this study was to determine whether a AOI strategy on non-ventilated lung could reduce the regional and systemic proinflammatory cytokine and oxidative stress response associated with esophagectomy, and to evaluate whether AOI can be used as a novel lung protective ventilation strategy. Its impact on oxygenation after OLV, surfactant protein A, B, C (SP-A, B, C), postoperative hospital stay and postoperative pulmonary complications (PPCs) was also evaluated.

Methods

Fifty-four adults (ASA II-III) undergoing esophagectomy with OLV were enrolled in the study. Patients were randomly assigned into 2 groups: control group (group C) and treated group (group T). Group C was treated with traditional OLV mode,while group T was given AOI of 5 L/min oxygen on the non-ventilated lung immediately at the beginning of OLV. Arterial blood gas was analyzed before and after OLV. A bronchoalveolar lavage(BAL) was performed after OLV on the non-ventilated lung. Proinflammatory cytokine, oxidative stress markers(TNF-α, NF-κB,sICAM-1,IL-6,IL-10,SOD,MDA) and SP-A, B, C were analyzed in serum and BALF as the primary endpoint.The clinical outcome determined by PPCs was assessed as the secondary endpoint.

Results

Patients with AOI had better oxygenation in the recovery period, oxygenation index(OI) (394[367–426] and 478[440–497]mmHg, respectively) of group T at T₂ and T₃ were significantly higher than those (332[206–434] and 437[331–512]mmHg, respectively) of group C. OLV resulted in an increase in the measured inflammatory markers in both groups, however, the increase of inflammatory markers upon OLV in the group C was significantly higher than those of group T. OLV resulted in an increase in the measured SP-A, B, C in serum of both groups. However, the levels of SP-A, B, C of group T were lower than those of group C in serum after OLV, and the results in BALF were the opposite. The BALF levels of SOD(23.88[14.70–33.93]U/ml) of group T were higher than those(15.99[10.33–24.16] U/ml) of group C, while the levels of MDA in both serum and BALF of group T(8.60[4.14–9.85] and 1.88[1.33–3.08]nmol/ml, respectively) were all lower than those of group C (11.10[6.57–13.75] and 1.280[1.01–1.83]nmol/ml) after OLV. There was no statistical difference between the two groups in terms of postoperative hospital stay and the incidence of PPCs.

Conclusion

AOI on non-ventilated lung during OLV can improve the oxygenation function after OLV, relieve the inflammatory and oxidative stress response in the systemic and non-ventilated lung after OLV associated with esophagectomy.

Trial registration

ChiCTR-IOR-17011037. Registered on 31 March 2017.

One-lung Ventilation for Thoracic Surgery: Current Perspectives

One-lung ventilation (OLV) is an anesthesiological technique that is increasingly being used beyond thoracic surgery. This requires specific skills and knowledge about airway management, maintenance of gas exchange and prevention of acute lung injury. Sometimes maintaining adequate gas exchange and minimizing acute lung injury may be opposing processes. Parameters validated for OLV titration still have not been found, but a multimodal approach based on low tidal volume, end-expiratory pressure application and alveolar recruitment maneuvers is considered the best way to ensure protective ventilation and reduce lung damage. The purpose of this review is to analyze all these factors using the latest scientific evidence and the opinions of the most influential authors.

Effectiveness of ventilation of nondependent lung for a brief period in improving arterial oxygenation during one-lung ventilation: A prospective study

Background:

Hypoxemia is common during one-lung ventilation(OLV), predominantly due to transpulmonary shunt. None of the strategies tried showed consistent results. We evaluated the effectiveness of ventilating the operated, non-dependent lung (NDL) with small tidal volumes in improving the oxygenation during OLV.

Methods:

30 ASA 1 and 2 patients undergoing elective, open thoracotomy were studied. After standard induction of anesthesia, lung seperation was acheived with left sided DLT. The ventilatory settings for two lung ventilation (TLV) were: FiO₂ of 0.5, tidal volume of 8-10ml/kg and respiratory rate of 10-12/min. After initiating OLV, the dependent lung alone was ventilated with the above settings for 15 minutes and an arterial blood gas (ABG) analysis was done. Then the NDL was ventilated with a separate ventilator, with FiO₂ of 1, tidal volume of 70 ml, I:E ratio of 1:10 and respiratory rate of 6/min for 15 minutes. The NDL ventilation was started early if the patients desaturated to <95%. ABG was done at 5 and 15 mins of NDL ventilation. We compared the PaO₂ values.

Results:

The mean PaO₂ decreased from 232.2 ± 67.2 mm of Hg (TLV-ABG1) to 91.2 ± 31.7 mm of Hg on OLV (OLV-ABG1). The ABG after 5 minutes and 15 minutes after institution of NDL ventilation during OLV showed a PaO2 of 145.7 ± 50.2 mm of Hg and 170.6 ± 50.4 mm of Hg which were significantly higher compared to the one lung ventilation values.

[Anesthesia in thoracic surgery]

Thoracic surgery represents a special challenge for anesthesia and requires a high level of human and material resources. Accurate knowledge of the pathophysiology is essential for selection of the anesthetic procedure, the separation of the lungs, monitoring and treatment of hemodynamics as well as for postoperative follow-up care. The increasing number of thoracic interventions and patients who are often suffering from complex diseases require close interdisciplinary cooperation between surgeons, anesthesiologists and intensive care specialists. In addition to the anesthetic techniques particular attention must be paid to the prevention of perioperative complications that can have a relevant effect on patient outcome. In particular hypoxemia during one-lung ventilation influences postoperative morbidity and mortality. Protective pulmonary ventilation strategies play an important role in prevention of postoperative acute lung injury.

Managing hypoxemia during minimally invasive thoracic surgery

An ever-increasing number of thoracic procedures are being performed through minimally invasive techniques. Although the incidence of hypoxemia during one-lung ventilation (OLV) has decreased over the years, it remains an issue in roughly 10% of cases. Algorithms for the management of OLV hypoxemia have to be adapted to the thoracoscopic approach, in particular the need for optimal surgical exposure. With appropriate planning and caution, most of the treatment modalities for OLV hypoxemia can be applied to the thoracoscopy setting, with some modifications.

Mini-ventilation for improved oxygenation during lung resection surgery

Lung separation is frequently used during lung resection to facilitate surgery and hypoxaemia may occur because of increasing pulmonary shunt. In this study, we tested a method of mini-ventilation to the non-dependent lung and compared it to continuous positive airway pressure (CPAP) to improve oxygenation during lung resection. Thirty-eight adult patients participated in this randomised, single-blinded crossover study. Following lung separation, mini-ventilation and CPAP of 5 cmH2O were alternately applied every 15 minutes to the non-dependent lung. Mini-ventilation was performed by a portable time-cycled ventilator with a respiratory rate of 8 breaths/minute and a tidal volume of 0.1 to 0.15 l. Arterial blood gases, peak inspiratory pressure, the dynamic compliance in the dependent lung and the surgeon's evaluation of the surgical field exposure were recorded. The arterial oxygen partial pressure was significantly higher during mini-ventilation compared to CPAP (379 vs 228 mmHg). No difference was noted in the dependent lung peak inspiratory pressure or in the dynamic compliance. The surgical conditions were similar with both methods in 53% of the patients, while the surgeon preferred CPAP in 44% and mini-ventilation in 3%. In conclusion, mini-ventilation is a simple method which improves oxygenation during lung resection. However due to interference with surgical field exposure, it should be reserved for cases in which CPAP does not relieve hypoxaemia.

One-lung ventilation and arterial oxygenation

PURPOSE OF REVIEW

Hypoxemia during one-lung ventilation (OLV) has become less common; however, it may still occur in about 10% of cases. We review recent developments which may affect the incidence and treatment of hypoxemia during OLV.

RECENT FINDINGS

Changes in surgical techniques are affecting oxygenation during OLV. The increased use of the supine position may adversely affect the prevalence of hypoxemia, whereas the increased application of thoracoscopic techniques is limiting the treatment options. Treatment options such as global or selective recruitment maneuvers and drug effects of dexmedetomidine and epoprostenol on arterial oxygenation during OLV are discussed. Capnometry prior to, or early during OLV, may in fact be able to predict the degree of hypoxemia during OLV. Persistent controversies surrounding the effect of epidural anesthesia, ventilatory modalities and gravity are reviewed.

SUMMARY

Interesting concepts have emerged from case reports and small studies on the treatment and prediction of hypoxemia during OLV. Definitive studies on the most effective ventilatory mode remain elusive. End-organ effects of OLV are an exciting new concept that may shape clinical practice and research going forward.

Surgery for secondary spontaneous pneumothorax

PURPOSE OF REVIEW

Secondary spontaneous pneumothorax (SSP) can occur in patients who are suffering from diffuse lung disease. The main cause of SSP is chronic obstructive pulmonary disease (COPD). In contrast to primary spontaneous pneumothorax, SSP is a potentially life-threatening condition because patients with SSP also have limited cardiopulmonary reserve. Prompt diagnosis and treatment of SSP are mandatory. In this review, thoracoscopy, a less invasive surgical treatment for SSP, is discussed from the viewpoint of postoperative morbidity, mortality, and recurrence of SSP.

RECENT FINDINGS

A meta-analysis showed that postoperative recurrence of pneumothorax is more frequently observed following thoracoscopy than following open thoracotomy. Recent studies on thoracoscopic surgery for SSP have shown that the rate of postoperative morbidity is still high (15-27.7%) and thoracoscopy is sometimes replaced with open thoracotomy because of dense pleural adhesion or inability to maintain one-lung ventilation during surgery. However, many thoracic surgeons prefer to perform thoracoscopic surgery for SSP because it is less invasive than open thoracotomy. Techniques for bullectomy and pleurodesis are currently being adapted to decrease the recurrence rate of pneumothorax.

SUMMARY

Thoracoscopic surgery for the treatment of SSP should be less invasive to reduce postoperative morbidity, and it should also be more effective to reduce the recurrence of pneumothorax.

Management of complications of minimally invasive thoracic surgery

Minimally invasive thoracic surgery (MITS) has become part of the modern thoracic surgeon's armamentarium. Its applications include diagnostic and therapeutic procedures, and over the past one and a half decades, the scope of MITS has undergone rapid evolution. The role of MITS is well established in the management of pleural and mediastinal conditions, and it is beginning to move beyond diagnostic procedures for lung parenchyma conditions, to gain acceptance as a viable option for primary lung cancer treatment. However MITS poses technical challenges that are quite different from the conventional open surgical procedures. After a brief review of the history of MITS, an overview of the scope of MITS is given. Important examples of diagnostic and therapeutic indications are then discussed, with special emphasis on the potential complications specific to MITS, and their prevention and management.