Continuous intraoperative neuromonitoring of the recurrent laryngeal nerve during lung operations

Background

The recurrent laryngeal nerve (RLN), especially on the left side, is particularly vulnerable during lung operations. Therefore, continuous intraoperative neuromonitoring (cIONM) would be desirable. With the use of a double-lumen tube (DLT) for single-lung ventilation, there is some uncertainty where the recording electrode should be positioned. The aim of this study was to assess the feasibility of this technique and to predict the ideal position of a single recording electrode.

Methods

Patients scheduled to undergo left thoracotomy due to pulmonary pathologies, two adhesive electrodes were affixed consecutively above the proximal cuff of the DLT prior to intubation for a precise location of the recording from the vocal cords. Following thoracotomy, the vagus nerve alongside the aortic arch was exposed. A continuous stimulation probe (Saxophone® electrode, Dr. Langer Medical, Waldkirch, Germany) was placed around the nerve. The signals of the respective electrode were recorded and analyzed with regard to previously defined limits of positive signaling.

Results

Strong signals with an amplitude of at least 165 µV were recorded in 18 of 20 patients. In these patients 100% of the signals were recorded via the distally located electrode. An additional signal was recorded via the proximal electrode in four patients. cIONM was found to be a safe and reproducible technique.

Conclusions

The described technique enables the use of cIONM of the RLN throughout the entire course of the surgical procedure.

Hypoxemia in thoracoscopic lung resection surgery using a video double-lumen tube versus a conventional double-lumen tube: A propensity score-matched analysis

Background

Malposition of the double-lumen tubes (DLTs) may lead to hypoxemia during one-lung ventilation (OLV). Video double-lumen tubes (VDLTs) enable continuous observation of DLT position and avoid displacement. We aimed to investigate whether VDLTs could reduce the incidence of hypoxemia during OLV compared with conventional double-lumen tubes (cDLT) in thoracoscopic lung resection surgery.

Methods

This was a retrospective cohort study. Adult patients who underwent elective thoracoscopic lung resection surgery and required VDLTs or cDLTs for OLV at Shanghai Chest Hospital from January 2019 to May 2021 were included. The primary outcome was the incidence of hypoxemia during OLV between VDLT and cDLT. Secondary outcomes included bronchoscopy use, the degree of PaO₂ decline, and arterial blood gas indices.

Results

A total of 1,780 patients were finally analyzed in propensity score-matched cohorts (VDLT vs. cDLT 1:1 n = 890). The incidence of hypoxemia decreased from 6.5% (58/890) in cDLT group to 3.6% (32/890) in VDLT group (Relative Risk [RR]: 1.812, 95% CI: 1.19-2.76, p = 0.005). The use of bronchoscopy was reduced by 90% in VDLT group (VDLT 10.0% (89/890) vs. cDLT 100% (890/890), p < 0.001). PaO₂ after OLV was 221 [136.0-325.0] mmHg in cDLT group compared to 234 [159.7-336.2] mmHg in VDLT group, p = 0.003. The percentage of PaO₂ decline was 41.4 [15.4-61.9] % in cDLT group, while it was 37.7 [8.7-55.9] % in the VDLT group, p < 0.001. In patients who suffered from hypoxemia, there were no significant differences in arterial blood gas indices or the percentage of PaO₂ decline.

Conclusion

VDLTs reduce the incidence of hypoxemia and the use of bronchoscopy during OLV compared with cDLTs. VDLT may be a feasible option for thoracoscopic surgery.

A comparison between bronchial blockers and double-lumen tubes for patients undergoing lung resection: A propensity score-matched cohort study

Objective: The aim of this study is to compare the effect of bronchial blockers (BB) and double-lumen tubes (DLT) on patients' postoperative recovery after lung resection. Method: 4,636 patients undergoing lung resection and receiving either BB or DLT intubation were reviewed and matched using the propensity score matching method. The primary outcome was the surgical duration. The secondary outcomes included diagnostic results of postoperative chest X-ray, postoperative oxygenation index, incidence of hypercapnia, hypoxemia and sore throat, chest tube duration, incidence of ICU admission, length of hospital stay and incidence of the 30-day readmission. Results: After matching, 401 patients receiving BB were matched to 3,439 patients receiving DLT. There was no statistical difference on the surgical duration between the two groups (P>0.05). However, compared with the DLT group, patients in the BB group showed more infiltrate especially at the surgery side (14.96% versus 9.07%, P<0.001) based on the chest X-ray, together with higher incidence of ICU admission (5.23% versus 2.61%, P<0.05). Additionally, no statistical differences were found between the two groups about chest tube duration, oxygenation index, incidence of hypercapnia, hypoxemia and sore throat, duration of surgery, hospital stays and 30-day readmission (P>0.05). Conclusions: Compared with the DLT, patients receiving BB technique tend to have increased pulmonary infiltrate (especially the surgery side) and higher incidence of ICU admission at the early post-operative stage, which may have an influence on the patients' recovery.

Bronchial suction does not facilitate lung collapse when using a double-lumen tube during video-assisted thoracoscopic surgery: a randomized controlled trial

Background

Bronchial suction through the lumen of a bronchial blocker has been reported to accelerate lung collapse. The aim of the current study was to examine whether bronchial suction could also facilitate lung collapse when using a double-lumen tube (DLT).

Methods

Eighty patients scheduled for elective video-assisted thoracoscopic surgery for lung cancer using a DLT for one-lung ventilation (OLV) were randomised into an arm that received bronchial suction and an arm that underwent spontaneous collapse (n=40 per arm). For bronchial suction, a pressure of -30 cmH₂O was applied to the lumen of the non-ventilated lung during the first minute of OLV. The primary endpoint was the degree of lung collapse at 10 min after the start of OLV, assessed on a 10-point visual analogue scale (0: fully inflated; 10: complete collapse). Secondary outcomes included lung collapse at 1 and 5 min after the start of OLV, as well as occurrence of intraoperative hypoxemia.

Results

Median (interquartile range) lung collapse scores at 10 min were statistically greater in the bronchial suction arm than in the spontaneous collapse arm [9.0 (9.0-9.0) vs. 8.5 (8.0-9.0); P=0.004]. Lung collapse was also statistically greater in the bronchial suction arm at 5 min [8.0 (7.0-8.0) vs. 7.0 (6.25-7.0) min; P=0.002] and 1 min [4.0 (4.0-5.0) vs. 2.0 (2.0-2.0) min; P<0.001]. None of the patients experienced intraoperative hypoxemia and operative complications.

Conclusions

Bronchial suction resulted in statistically greater but not clinically meaningful lung collapse when using a DLT. However, greater degree of lung collapse at 1-min could be helpful in reducing accidental injuries.