Seok Young Song

Predicting the difficulty in performing a neuraxial blockade

Background Traumatic placement of a needle during a neuraxial blockade has been related to many complications such as postdural puncture headache, trauma to neural structures and even spinal hematoma, causing permanent neurologic deficits. Although efforts to minimize the complications caused by traumatic neuraxial blockade have been made, nothing was found to be clear. The authors investigated the predictors of difficult neuraxial blockade using the first puncture success and number of attempts as measures to assess the difficulty. Methods In this prospective observational study, 253 patients scheduled for elective surgery underwent spinal or epidural anesthesia. Patient data (age, sex, height, weight, body mass index, and quality of anatomical landmarks), the providers level of experience, type of blockade (spinal or epidural), needle type/gauge and the distance from skin to subarachnoid or epidural space were recorded. Significant variables were first determined by Students t-test and Pearsons chi square test and then logistic and Poisson regression tested the association of the first puncture success and number of attempts with the significant variables. Results The providers level of experience and the distance from skin to subarachnoid or epidural space were significant in logistic and Poisson regression. Body mass index was significant only in Poisson regression and the quality of anatomical landmarks was significant only in logistic regression. Conclusions Providers level of experience and the distance from skin to subarachnoid or epidural space influenced the difficulty in performing a neuraxial blockade.

Hypotensive bradycardic events during shoulder arthroscopic surgery under interscalene brachial plexus blocks

Sudden, profound hypotensive and bradycardic events (HBEs) have been reported in more than 20% of patients undergoing shoulder arthroscopy in the sitting position. Although HBEs may be associated with the adverse effects of interscalene brachial plexus block (ISBPB) in the sitting position, the underlying mechanisms responsible for HBEs during the course of shoulder surgery are not well understood. The basic mechanisms of HBEs may be associated with the underlying mechanisms responsible for vasovagal syncope, carotid sinus hypersensitivity or orthostatic syncope. In this review, we discussed the possible mechanisms of HBEs during shoulder arthroscopic surgery, in the sitting position, under ISBPB. In particular, we focused on the relationship between HBEs and various types of syncopal reactions, the relationship between HBEs and the Bezold-Jarisch reflex, and the new contributing factors for the occurrence of HBEs, such as stellate ganglion block or the intraoperative administration of intravenous fentanyl.

Volume-controlled versus pressure-controlled ventilation-volume guaranteed mode during one-lung ventilation

Background The 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. Methods We 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. Results Ppeak 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). Conclusions During 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.

Intravenous fentanyl during shoulder arthroscopic surgery in the sitting position after interscalene block increases the incidence of episodes of bradycardia hypotension.

Background Episodes of bradycardia hypotension (BH) or vasovagal syncope have a reported incidence of 13-29% during arthroscopic shoulder surgery in the sitting position after an interscalene block (ISB). This study was designed to investigate whether intravenous fentanyl during shoulder arthroscopy in the sitting position after ISB would increase or worsen the incidence of BH episodes. Methods In this prospective study, 20 minutes after being in a sitting position, 160 patients who underwent ISB were randomized to receive saline (S, n = 40), 50 µg of fentanyl (F-50, n = 40), 100 µg of fentanyl (F-100, n = 40) or 30 mg of ketorolac (K-30, n = 40) randomly. We assessed the incidence of BH episodes during the operation and the degree of maximal reduction (Rmax) of blood pressure (BP) and heart rate (HR). Results The incidence of BH episodes was 10%, 15%, 27.5% and 5% in the S, F-50, F-100 and K-30 groups, respectively. Mean Rmax of systolic BP in the F-100 group was significantly decreased as compared to the S group (-20.0 ± 4.5 versus -6.3 ± 1.6%, P = 0.004). Similarly, mean Rmax of diastolic BP in the F-100 group was also significantly decreased (P = 0.008) as compared to the S group. Conclusions These results suggest that fentanyl can increase the incidence of BH episodes during shoulder arthroscopic surgery in the sitting position after ISB.

Injury to the spinal cord by a thoracic epidural catheter used to control postpneumonectomy pain - A case report -

A thoracotomy is one of the most severe painful operations. This severe pain can usually be controlled by thoracic epidural analgesia. Epidural catheterization for analgesia has several complications, e.g., epidural hematoma, abscess, spinal stenosis, spinal infarction, direct cord trauma, and neurotoxicity by chemical contamination. These complications can cause acute paraplegia, but permanent paraplegia is extremely rare. We report a case of paresthesia and temporary paralysis in a 54-year-old patient who suffered spinal cord injury after thoracic epidural catheterization for the control of postpneumonectomy pain under general anaesthesia.

Combined femoral and popliteal sciatic nerve blocks versus epidural anesthesia in great saphenous veins stripping surgery with multiple stab avulsion

BACKGROUND This study was designed to test the hypothesis that a combined femoral and politeal sciatic nerve blocks (FPSNB) would have excellent clinical properties and better patient satisfaction than epidural anesthesia for the great saphenous veins stripping (GSVS) surgery with multiple stab avulsion (MSA). METHODS Sixty patients were allocated into two groups. The epidural group received epidural anesthesia with 15 ml of 0.75% ropivacaine (n = 30), and the FPSNB group received a combined FPSNB with 25 ml of 1.5% mepivacaine with a nerve stimulator (n = 30). We assessed the anesthetic and postoperative records. A questionnaire-based study including patient satisfaction for anesthetic techniques (100 point scale) was conducted 3 days postoperatively by a blinded observer. RESULTS The time from initial injection to the start of surgery and the duration of sensory blockade were not different between groups (P > 0.05). The percentage of patients with anesthesia-related complications in epidural anesthesia was 33.3%, 46.6%, 23.3% and 20% for shivering, hypotension, bradycardia and postoperative voiding difficulty, respectively. FPSNB did not produce these complications. Additional analgesia with 50-100 microgram of fentanyl was more frequently used in FPSNB (60% vs 6.7%, FPSNB vs Epidural group, P < 0.01), but patient satisfaction of FPSNB was higher than epidural anesthesia (88.1 +/- 13.2 vs 76.5 +/- 15.8, FPSNB vs Epidural group, P < 0.01). CONCLUSIONS A combined FPSNB with a small amount of narcotics is an adequate anesthetic technique for unilateral GSVS surgery with MSA.