BackgroundThe purpose of this study was to investigate the changes in airway pressure and arterial oxygenation between ventilation modes during one-lung ventilation (OLV) in patients undergoing thoracic surgery.MethodsWe enrolled 27 patients for thoracic surgery with OLV in the lateral decubitus position. The subjects received various modes of ventilation in random sequences during surgery, including volume-controlled ventilation (VCV) and pressure-controlled ventilation-volume guaranteed (PCV-VG) with a tidal volume (TV) of 8 ml/kg of actual body weight. Target-controlled infusion (TCI) with propofol and remifentanil was used for anesthesia induction and maintenance. After double-lumen endobronchial tube (DLT) insertion, the proper positioning of the DLT was assessed using a fiberoptic bronchoscope. Peak inspiratory pressure (Ppeak), exhaled TV, and arterial blood gas were measured 30 min after each ventilation mode.ResultsPpeak was significantly reduced with the PCV-VG mode (19.6 ± 2.5 cmH2O) compared with the VCV mode (23.2 ± 3.1 cmH2O) (P < 0.000). However, no difference in arterial oxygen tension was noted between the groups (PCV-VG, 375.8 ± 145.1 mmHg; VCV, 328.1 ± 123.7 mmHg) (P = 0.063). The exhaled TV was also significantly increased in PCV-VG compared with VCV (451.4 ± 85.4 vs. 443.9 ± 85.9 ml; P = 0.035).ConclusionsDuring OLV in patients with normal lung function, although PCV-VG did not provide significantly improved arterial oxygen tension compared with VCV, PCV-VG provided significantly attenuated airway pressure despite significantly increased exhaled TV compared with VCV.

Background:Dexmedetomidine is a sedative and analgesic agent that is administered intravenously as an adjunct to spinal anesthesia. It does not suppress the respiratory system significantly, but has adverse effects on the cardiovascular system, for example, bradycardia and hypotension. We here report a patient who underwent cardiac arrest during spinal anesthesia after intravenous infusion of dexmedetomidine.Methods:A 57-year-old woman with no significant medical history underwent spinal anesthesia for arthroscopic meniscus resection after rupturing the right knee meniscus. Preoperative electrocardiogram revealed sinus bradycardia (54 beats/min) and a left anterior fascicular block. Spinal anesthesia was performed with 11 mg of 0.5% heavy bupivacaine, and the upper level of sensory loss was at T6. Dexmedetomidine infusion was planned at a loading dose of 1.0 mcg kg−1 min−1 over 10 minutes, followed by 0.7 mcg kg−1 min−1 intravenously, as a sedative. Two minutes after dexmedetomidine injection, her heart rate decreased to 31 beats/min and asystole was observed within 10 seconds.Results:After a few minutes of cardiopulmonary resuscitation, spontaneous circulation returned and surgery was completed under general anesthesia. The patient was discharged, and experienced no complications.Conclusion:Dexmedetomidine can decrease blood pressure and heart rate, and may cause asystole in some cases. We suggest that dexmedetomidine should be carefully administered under close observation when the parasympathetic nerve system is activated during spinal anesthesia.

Rationale:A variety of therapeutic modalities are available for the treatment of interstitial cystitis. However, among them, the less invasive therapies are usually ineffective, whereas the invasive ones carry potential risks of serious side effects and complications. Pulsed radiofrequency (PRF) treatment of the superior hypogastric plexus may be an alternative to conventional treatments, as it provides nondestructive neuromodulation to the superior hypogastric plexus, which transmits the majority of pain signals from the pelvic viscera.Patient concerns:For 7 years, a 35-year-old female patient had been experiencing lower abdominal pain provoked by urinary bladder filling, perivulvar pain developing spontaneously during sleep or upon postural change, urinary urgency and frequency with 15- to 60-min intervals between urinations, and nocturia with 10 voids per night. Hydrodistension of the bladder, monthly intravesical administration of sterile sodium chondroitin sulfate, and oral medications including gabapentin and pentosan polysulfate had not been effective in managing the pain and symptoms.Diagnoses and interventions:Given the satisfactory result of a diagnostic block of the superior hypogastric plexus, 2 sessions of PRF treatment of the superior hypogastric plexus, which applied radiofrequency pulses with a pulse frequency of 2 Hz and a pulse width of 20 ms for 120 s twice per session to maintain the tissue temperature near the electrode at 42°C, were performed at a 6-month interval.Outcomes:This treatment relieved the pain and symptoms for 2 years and 6 months.Lessons:PRF treatment of the superior hypogastric plexus results in long-term improvements in the pain and symptoms associated with interstitial cystitis.