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Rationale: Rigid bronchoscopy under general anesthesia enables performing diagnostic and/or therapeutic procedures in the tracheobronchial tree. As most patients undergoing rigid bronchoscopy have moderate to severe respiratory disease or central airway obstruction, the operators often face the risk of hypoxemia when inserting the rigid bronchoscope into the patients’ airway. Applying high flow nasal cannula (HFNC) oxygen therapy before the insertion of the bronchoscope allows to maintain high fractional inspired oxygen (FiO2) and thus leading to maximizing apnea time before desaturation. Patient concerns and diagnosis: Case 1: A 70-year-old female patient was diagnosed with lung cancer in the left lower lobe and a tracheal mass of about 2.6 cm ∗ 0.8 cm in size. Case 2: A male patient, 77 years old, 55.7 kg and 157.3 cm in height, had been diagnosed with chronic obstructive pulmonary disease, and was scheduled for the bronchoscopic volume reduction surgery upon exacerbation of his symptoms of dyspnea and cough with sputum. Interventions: Preoxygenation was performed with HFNC (Fisher&Paykel Optiflow ThriveTM, New Zealand) for 3 minutes before the administration of anesthetic medications. The oxygen flow was set at 50 L/min and the FiO2 at 1.0. SpO2 increased to 100%. Outcomes: The HFNC oxygen has shown its effectiveness in safely maintaining the patients’ SpO2 during the prolonged apneic period of inserting bronchoscope. Lessons: HFNC oxygen is an effective tool in oxygenating the patients during the induction of rigid bronchoscopy, and that it may be a superior alternative to the conventional method of preoxygenation.

Introduction Venous air embolism (VAE) from vascular injuries, is of rare occurrence but can result in catastrophic complications during total hip arthroplasty (THA). Early recognition and prompt management of vascular injury are required to avoid severe complications. Especially, bleeding is generally associated with profound hypotension in venous injury. We report an unusual complication of venous air embolism induced by femoral vein rupture during THA. Patient concerns A 54-year-old male patient with a history of old left acetabular fracture was scheduled for THA. We experienced massive bleeding and VAE induced by femoral vein rupture during total hip arthroplasty. The BP suddenly dropped from 100/70 mm Hg to 80/50 mm Hg with massive bleeding. ETCO2 and SaO2 decreased profoundly. Diagnosis The VAE was diagnosed by the change in end- tidal CO2 (ETCO2) and change of vital signs, so we performed ABGA and inserted TEE for confirmination. Interventions For treatment, patient was managed by oxygen therapy, inotropics, vasopressor, transfusion and surgical repair. Outcomes Upon consulting with a cardiologist, the patient was extubated the next day and was transferred to the general ward and recovered without serious complications. He stayed for 17 days until finally discharged without complications. Conclusion Preoperative vascular imaging may be recommended in the revisional case of THA or in patients with the history of hip trauma. The monitoring of ETCO2 and TEE might be helpful to recognize VAE earlier and therefore to avoid catastrophic complications through adequate treatment.

Background: There is a risk of drug sorption into an intravenous administration set composed of polyvinyl chloride (PVC), polyurethane (PU), or polyolefin (PO). This has implications on the dose of the active ingredient the patient receives, and thus therapeutic success. This study aimed to determine the plasma concentration of nitroglycerin and the effect of nitroglycerin on patients based on the composition of the administration set. Methods: Using a randomized, open-labeled, 3 × 3 crossover method, 9 volunteers were assigned to 3 groups. In period I, nitroglycerin (100 μg/mL) was infused via a PVC- (group A), PU- (group B), or PO-based (group C) administration set. In period II, PU- (group A), PO- (group B), and PVC-based (group C) administration sets were used, and in period III, PO- (group A), PVC- (group B), and PU-based (group C) administration sets were used. The rate of drug administration in all periods was 12 mL/hour for 30 minutes using an infusion pump. Blood samples were collected, and the plasma concentrations of nitroglycerin were analyzed using validated high-performance liquid chromatography coupled with tandem mass spectrometry. Blood pressure was determined using a sphygmomanometer applied to the other upper arm at an interval of 5 minutes. Results: We observed that the mean plasma concentration of nitroglycerin over time when administered using a PO-based tube was higher than that when using a PU- or PVC-based tube. When the percent change of the mean arterial pressure from baseline at each time point was compared among groups, there were statistically significant differences between PU and PO or PVC at most points during nitroglycerin infusion. Conclusion: Our results showed higher nitroglycerin plasma concentration and lower arterial pressure when a PO-based administration set was used than when a PVC- or PU-based administration set was used. PO-based administration sets may be more appropriate for nitroglycerin administration compared to those composed of PVC or PU.