The feasibility of NBI in patients with suspected upper airway lesions: A multicenter study.

OBJECTIVE: Narrow band imaging (NBI) improves diagnosis of laryngopharyngeal cancer, but most reported NBI studies are from experienced centers. Feasibility reports on use at everyday outpatient departments are needed. STUDY DESIGN: Researcher-initiated, prospective, multicenter. METHODS: Participating physicians were instructed in NBI technique during a 4-hour meeting. Patients underwent an examination that included endoscopy with white light (WL) high-definition (HD) TV and NBI filter in the selected time period. All suspicious lesions were biopsied. The medical records of patients with NBI negative findings were evaluated 6 months after the visit to detect all possible malignant lesions coming into view at mucosal sites. These were considered as false-negative cases, enabling long-term assess to the positive predictive value (NPV) of the protocol. RESULTS: We enrolled 125 patients. Of those, 84 (67.2%) were males and the median age was 65 years (range, 35-91). In analysis of the accuracy of WL HD TV and NBI against biopsy, the sensitivity and specificity of WL HD TV were 62% and 81%, respectively; and the sensitivity and specificity of NBI were 100% and 84%, respectively. The diagnostic accuracy of NBI was significantly better (P < 0.05). When analyzing medical records 6 months after the initial examination, we found three patients who had been diagnosed with a malignant lesion (NPV of NBI of 96.8%). CONCLUSION: Narrow band imaging is readily implemented in an everyday outpatient practice, and there seems to be better detection rates of dysplastic/carcinoma lesions with HD NBI compared to HD WL. LEVEL OF EVIDENCE: 2b. Laryngoscope, 127:1821-1825, 2017.

The Effect of Norepinephrine and Dopamine on Radial Forearm Flap Partial Tissue Oxygen Pressure and Microdialysate Metabolite Measurements: A Randomized Controlled Trial.

BACKGROUND: Patients undergoing ablative and reconstructive head and neck surgery with a microvascular flap have multiple factors that potentially decrease postoperative mean arterial pressure, which may endanger flap survival. The safety of vasopressor use has long been a topic of discussion. The authors analyzed the effect of vasopressors on microvascular flap perfusion after head and neck cancer reconstruction. METHODS: A total of 27 patients were enrolled in a randomized, controlled, clinical trial. A microvascular radial forearm flap was used for reconstruction. Patients were allocated into one of three groups: dopamine, norepinephrine, and control. The intervention groups received the vasoactive drug, aiming to maintain the mean arterial pressure between 80 and 90 mmHg. Normovolemia was maintained according to central venous pressure. Flap perfusion was monitored with continuous tissue partial pressure of oxygen and microdialysate metabolite (lactate-to-pyruvate ratio) measurements. RESULTS: No adverse effects were observed, and postoperative recovery was free of complications in all groups. Neither the lactate-to-pyruvate ratio nor continuous tissue partial pressure of oxygen values differed significantly between groups during the first 24 hours of the vasoactive drug infusion period or during the 72-hour follow-up. CONCLUSIONS: Norepinephrine and dopamine are safe and effective vasopressors for use during the postoperative period following head and neck cancer surgery with microvascular reconstruction. Dopamine should be used with caution, however, because of the risk of side effects. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, II.

Sympathetic innervation does not contribute to glycerol release in ischemic flaps.

BACKGROUND: Extracellular glycerol as detected by microdialysis has been used as a surrogate marker for (ischemic) tissue damage and cellular membrane breakdown in the monitoring of free microvascular musculocutaneous flaps. One confounding factor for glycerol as a marker of ischemic cell damage is the effect of lipolysis and associated glycerol release as induced by sympathetic signalling alone. We hypothesized that extracellular glycerol concentrations in a microvascular flap with sympathetic innervation would be confounded by intact innervation per se as compared to denervated flap. Clinical relevance is related to the use of both free and pedicled flaps in reconstructive surgery. We tested the hypothesis in an experimental model of microvascular musculocutaneal flaps. METHODS: Twelve pigs were anesthetized and mechanically ventilated. Two identical rectus abdominis musculocutaneal flaps were raised for the investigation. In the A-flaps the adventitia of the artery and accompanying innervation was carefully stripped, while in the B-flaps it was left untouched. Flap ischemia was induced by clamping both vessels for 60 minutes. The ischemia was confirmed by measuring tissue oxygen pressure, while extracellular lactate to pyruvate ratio indicated the accompanying anaerobic metabolism locally. RESULTS: Intramuscular and subcutaneal extracellular glycerol concentrations were measured by microdialysate analyzer. Contrary to our hypothesis, glycerol concentrations were comparable between the two ischemia groups at 60 minutes (p = 0.089, T-test). CONCLUSIONS: In this experimental model of vascular flap ischemia, intact innervation of the flap did not confound ischemia detection by glycerol. Extrapolation of the results to clinical setting warrants further studies.