One lung ventilation (OLV) is a common technique used in thoracic surgeries, including video-assisted procedures, to provide a clearer surgical field. However, it can lead to hypoxemia due to reduced oxygenation. A recent clinical trial published by the Journal of Cardiothoracic Surgery investigated the use of differential lung ventilation (DLV) as an alternative to continuous positive airway pressure (CPAP), with promising results. This article delves into the study’s methodology, findings, and implications for improving patient outcomes during lung resection surgery.
Introduction
One lung ventilation (OLV) is a pivotal technique in thoracic surgery, particularly for procedures such as video-assisted lung resection. OLV facilitates optimal surgical conditions by deflating the operative lung, thereby improving visibility and access for the surgeon. Nonetheless, this approach comes with the risk of hypoxemia, a deficiency in blood oxygen levels, due to a shunt effect where blood bypasses the non-ventilated lung without being oxygenated. Addressing hypoxemia is crucial to patient safety and surgical success.
To combat hypoxemia during OLV, techniques such as CPAP have been used to bolster oxygenation in the non-dependent lung. However, a recent study published in the Journal of Cardiothoracic Surgery, DOI: 10.1186/s13019-019-0910-2, suggests that DLV may be a superior method for enhancing oxygenation during video-assisted lung surgeries. The aim of this article is to provide a comprehensive analysis of the clinical trial comparing CPAP and DLV, detail its results, and discuss the potential impact on perioperative care in thoracic surgery.
Methodology
The prospective study, registered with ClinicalTrials.gov (NCT03563612), involved 30 adult patients undergoing elective video-assisted thoracoscopic lung lobectomy. The patients were alternately ventilated using four different modes: two lung ventilation (TLV), OLV, OLV with CPAP (OLV+CPAP), and OLV with DLV (OLV+DLV). Participants were divided into two groups, with one group receiving CPAP before DLV and the other group receiving the interventions in the opposite order. Each mode was maintained for five minutes, with the non-dependent lung opened to room air in between.
Surgeons, blinded to the ventilation technique being used, were asked to gauge the surgical field conditions for each intervention. Meanwhile, arterial blood gases (ABGs) were measured to assess patient oxygenation under each ventilation mode. The primary outcome was the difference in oxygenation between OLV with CPAP and OLV with DLV.
Results
The findings indicated a significant improvement in oxygenation during OLV with DLV compared to OLV with CPAP (p=0.018). There were no significant alterations in pH, PCO2, and HCO3 indicative of stable acid-base balance across different ventilating modes. Moreover, the surgeons reported no significant difference in their assessment of surgical field conditions between OLV with CPAP and OLV with DLV (p=0.073). Consequently, DLV proved to be a valuable technique where CPAP failed to alleviate hypoxemia during OLV.
Discussion
The superior oxygenation offered by DLV could be attributed to the more nuanced control over ventilation and the ability to adjust tidal volumes and pressures individually for each lung. By ventilating the non-dependent lung with minimal volume, DLV can maintain some degree of gas exchange while minimizing interference in the operative field.
These results are consistent with previous studies emphasizing the need for alternative strategies to improve oxygenation during OLV. For instance, as reviewed by Karzai and Schwarzkopf, addressing hypoxemia during one-lung ventilation is crucial for patient safety, especially given the variations in individual patient responses to OLV (Anesthesiology, 2009; DOI: 10.1097/ALN.0b013e31819fb15d).
Implications for Clinical Practice
The study authors, led by Kremer Ran et al., suggest that DLV could be adopted as an advanced strategy to improve oxygenation in patients who do not respond adequately to CPAP during OLV. It could also be considered as a first-line technique due to its favorable oxygenation profile. This could translate to decreased morbidity associated with hypoxic events during surgery and potentially shorter postoperative recovery times.
Future Research
While the results are promising, further studies may focus on optimizing DLV parameters for different patient populations and determining the long-term outcomes following the use of DLV in thoracic surgical procedures. Additionally, comparing the cost-effectiveness of DLV to CPAP could provide valuable information for healthcare providers.
Conclusion
The study provides evidence that DLV improves oxygenation compared to CPAP during OLV for video-assisted lung surgery. With the possibility of increased patient safety and surgical efficacy, DLV could soon be integrated into standard care for thoracic surgical operations. However, clinicians should weigh the benefits with costs and individual patient characteristics when choosing the optimal ventilation strategy.
Keywords
1. One lung ventilation
2. Differential lung ventilation
3. Video-assisted thoracic surgery
4. Hypoxemia management
5. OLV oxygenation techniques
References
1. Kremer Ran R., Aboud Wisam W., Haberfeld Ori O., Armali Maruan M., Barak Michal M. (2019). Differential lung ventilation for increased oxygenation during one lung ventilation for video assisted lung surgery. Journal of Cardiothoracic Surgery, 14(1), 89. DOI: 10.1186/s13019-019-0910-2.
2. Karzai W., Schwarzkopf K. (2009). Hypoxemia during one-lung ventilation: prediction, prevention, and treatment. Anesthesiology, 110, 1402-1411. doi: 10.1097/ALN.0b013e31819fb15d.
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