Assessment of the Operative Feasibility and Ventilation Distribution during Nonintubation Thoracoscopic Surgery Using Electrical Impedance Tomography.

Background: To investigate the feasibility, ventilation distribution, and physiological effect of iatrogenic pneumothorax generated during nonintubated thoracoscopic surgery using electrical impedance tomography. Methods: Patients who underwent resections for pulmonary nodules between April 2016 and April 2019 were enrolled prospectively. Electrical impedance tomography was performed, and the measurements were recorded at five different timepoints. The patient characteristics, pathological characteristics, surgical procedures, operation times, and intraoperative parameters were recorded and analyzed. Results: Two hundred sixty-five perioperative electrical impedance tomography measurements during nonintubated thoracoscopic surgery were recorded in fifty-three patients. Fifty-one patients underwent wedge resections, and two patients underwent segmentectomies. The preoperative lateral decubitus position time point showed greater ventilation in the right lung than in the left lung. For left-sided surgery, the nonoperative lung had better ventilation (64.5% ± 14.1% for the right side vs. 35.5% ± 14.1% for the left side, p < 0.0001). For right-sided surgery, the nonoperative lung did not have better ventilation (52.4% ± 16.1% for the right side vs. 47.6% ± 16.1% for the left side, p = 0.44). The center of ventilation was significantly increased after surgery (p < 0.001). The global index of ventilation showed no difference after surgery. Conclusions: The nonintubated thoracoscopic surgical side had different ventilation distributions but reached ventilation equilibrium after the operation. Electrical impedance tomography is feasible and safe for monitoring ventilation without adverse effects.

Qualitative and quantitative assessment of pendelluft: a simple method based on electrical impedance tomography.

BACKGROUND: Pendelluft, defined as asynchronous alveolar ventilation, is caused by different regional time constants or dynamic pleural pressure variations. The aim of the present study was to propose a simple method to evaluate pendelluft based on electrical impedance tomography (EIT). The efficacy of this method was demonstrated in well-known pendelluft scenarios in 6 patients. METHODS: Two patients with flail chest after accidents, two patients with acute respiratory distress syndrome (ARDS) and two patients with acutely exacerbated obstructive lung disease were prospectively included. EIT measurements were performed before and after surgery (in patients with flail chest, who had video-assisted thoracoscopic surgery with ribs fixation), or at two different levels of positive end-expiratory pressure (PEEP; ARDS patients), or two different time points (obstructive lung disease). Pendelluft was assessed by regional phase shift (defined as time difference between global and regional impedance-time curves) and amplitude differences (defined as the impedance difference between sum of all regional tidal variation and the global tidal variation). RESULTS: In patients with flail chest, pendelluft diminished several days after surgery (pendelluft amplitude normalized to tidal impedance variation reduced from 88% to 2% in one patient, 12% to 2% in the other). Increased PEEP reduced the amplitude of pendelluft (from 3% to 0% in one patient, 20% to 2% in the other) but not necessarily the phase shifts (average time differences were <0.1 second for both patients for both ins- and expiration) in ARDS patients. Pendelluft assessment in obstructive lung diseases reflected the change in airway resistance (from 5% to 1% in one patient after broncholytic medication administration, as airway resistance fell from 15 to 11 cmH2O/L/s; from 9% to 35% in the other patient with acute exacerbation, the corresponding airway resistance increased from 15 to 22 cmH2O/L/s). CONCLUSIONS: The proposed EIT-based method can be used to evaluate the degree of pendelluft in dimension of phase shift and amplitude difference.

Brain metastases in resected non-small cell lung cancer: The impact of different tyrosine kinase inhibitors.

OBJECTIVES: The purpose of this study was to examine the impact of epidermal growth factor receptor (EGFR) mutation status and tyrosine kinase inhibitors (TKIs) on the survival of brain metastases (BM) in patients with surgically resected non-small cell lung cancer (NSCLC). METHODS: We selected the patients who had developed metastatic NSCLC; analyzed the differences between brain metastases and other sites of metastases, including patient characteristics, EGFR status, and survival; and selected the patients who had BM for further investigation. We also compared the treatment effects of first-generation TKIs with those of second-/third-generation TKIs. RESULTS: A total of 785 cases of stage I-IIIa NSCLC were reviewed. Thirty-six (4.6%) patients were identified as having BM. Among them, 14 patients had a mutated EGFR status. No association between EGFR mutation and the incidence of BM was observed (p = 0.199). Patients with mutated EGFRs had significantly longer overall survival and post-recurrence survival than patients with wild-type EGFR mutation (p = 0.001 for both). However, there was no survival difference between patients with exon 19 and exon 21 mutations (p = 0.426). Furthermore, patients who received the second- and/or third-generation EGFR-TKIs had better survival than patients who only received first-generation EGFR-TKIs (p = 0.031). A multivariate analysis indicated that the next-generation TKIs (HR, 0.007; 95% CI, 0.000 to 0.556; p = 0.026) and a longer interval before BM development (HR, 0.848; 95% CI, 0.733 to 0.980; p = 0.025) were significant factors in longer survival. CONCLUSIONS: EGFR-TKIs were effective in treating NSCLC patients with BM after curative pulmonary surgery, especially in those patients harboring EGFR mutations. Furthermore, the second-/third-generation EGFR-TKIs showed more promising results than the first-generation EGFR-TKIs in treating those particular patients, though larger studies needed to further prove the results.

Comparison of different functional EIT approaches to quantify tidal ventilation distribution.

OBJECTIVE: The aim of the study was to examine the pros and cons of different types of functional EIT (fEIT) to quantify tidal ventilation distribution in a clinical setting. APPROACH: fEIT images were calculated with (1) standard deviation of pixel time curve, (2) regression coefficients of global and local impedance time curves, or (3) mean tidal variations. To characterize temporal heterogeneity of tidal ventilation distribution, another fEIT image of pixel inspiration times is also proposed. MAIN RESULTS: fEIT-regression is very robust to signals with different phase information. When the respiratory signal should be distinguished from the heart-beat related signal, or during high-frequency oscillatory ventilation, fEIT-regression is superior to other types. fEIT-tidal variation is the most stable image type regarding the baseline shift. We recommend using this type of fEIT image for preliminary evaluation of the acquired EIT data. However, all these fEITs would be misleading in their assessment of ventilation distribution in the presence of temporal heterogeneity. SIGNIFICANCE: The analysis software provided by the currently available commercial EIT equipment only offers either fEIT of standard deviation or tidal variation. Considering the pros and cons of each fEIT type, we recommend embedding more types into the analysis software to allow the physicians dealing with more complex clinical applications with on-line EIT measurements.

Endoscopic diverticulotomy with a stapler can be an effective and safe treatment for Killian-Jamieson diverticulum.

Killian-Jamieson diverticulum (KJD) is a rarely encountered esophageal diverticulum which attributes to several symptoms. Clinically, KJD should be differentiated from the most common type of esophageal herniation, i.e., Zenker's diverticulum (ZD). The two diverticula may present in a similar fashion, and treatments have evolved from transcervical to a minimally invasive endoscopic approach in recent years. We present a case of an 88-year-old male with symptomatic esophageal diverticulum. Barium swallow esophagogram and flexible esophagoscopy demonstrated a large KJD with food debris retention. Endoscopic diverticulotomy using a stapler was performed successfully without injury to the recurrent laryngeal nerve (RLN). A literature review and discussion concerning etiology, clinical presentations, and radiographic characteristics of KJD was conducted, and comparison between open and endoscopic method for esophageal diverticulum was also carried out.

Symptomatic pericardial schwannoma treated with video-assisted thoracic surgery: a case report.

Intrathoracic schwannomas are neurogenic tumors derived from the Schwann cells of the nerve sheath, most often seen in the posterior mediastinum with anatomical correlations to nerves. Although they are typically benign, a malignant transformation can occur, and thoracotomy instead of video-assisted thoracoscopic surgery (VATS) is required to achieve a complete resection. Only a few cases of pericardial schwannoma have been reported so far. We present a rare case of pericardial schwannoma confirmed by video-assisted thoracoscopic resection.