Eighth Cervical Nerve Root Block During Interscalene Brachial Plexus Block Decreases Pain Caused by Posterior Portal Placement but Increases Horner Syndrome in Patients Undergoing Arthroscopic Shoulder Surgery: A Randomized Controlled Trial.

PURPOSE: To compare the intensity of pain on posterior portal placement between a C5-C7 root block (conventional interscalene brachial plexus block [ISBPB]) and a C5-C8 root block in patients undergoing arthroscopic shoulder surgery. METHODS: In this prospective, single-blinded, parallel-group randomized controlled trial, patients were randomized to receive either a C5-C7 root block (C5-C7 group, n = 37) or a C5-C8 root block (C5-C8 group, n = 36) with 25 mL of 0.75% ropivacaine. The primary outcome was the pain intensity on posterior portal placement, which was graded as 0 (no pain), 1 (mild pain), or 2 (severe pain). The secondary outcomes were the bilateral pupil diameters measured 30 minutes after ISBPB placement; the incidence of Horner syndrome, defined as a difference in pupil diameter (ipsilateral - contralateral) of less than -0.5 mm; the onset of postoperative pain; and the postoperative numerical rating pain score, where 0 and 10 represent no pain and the worst pain imaginable, respectively. RESULTS: Fewer patients reported mild or severe pain on posterior portal placement in the C5-C8 group than in the C5-C7 group (9 of 36 [25.0%] vs 24 of 37 [64.9%], P = .003). Less pain on posterior portal placement was reported in the C5-C8 group than in the C5-C7 group (median [interquartile range], 0 [0-0.75] vs 1 [0-1]; median difference [95% confidence interval], 1 [0-1]; P = .001). The incidence of Horner syndrome was higher in the C5-C8 group than in the C5-C7 group (33 of 36 [91.7%] vs 22 of 37 [59.5%], P = .001). No significant differences in postoperative numerical rating pain scores and onset of postoperative pain were found between the 2 groups. CONCLUSIONS: A C5-C8 root block during an ISBPB reduces the pain intensity on posterior portal placement. However, it increases the incidence of Horner syndrome with no improvement in postoperative pain compared with the conventional ISBPB (C5-C7 root block). LEVEL OF EVIDENCE: Level I, randomized controlled trial.

Effect of Minimum Bronchial Cuff Volume of Left-Sided Double-Lumen Tube for One-Lung Ventilation on the Change in Bronchial Cuff Pressure during Lateral Positioning in Thoracic Surgery: A Prospective Observational Study.

The minimum bronchial cuff volume (BCVmin) of a double-lumen tube (DLT) without air leaks during lung isolation may vary among individuals, and lateral positioning could increase the bronchial cuff pressure (BCP). We investigated the effect of initially established BCVmin (BCVi) on the change in BCP by lateral positioning. Seventy patients who underwent elective lung surgery were recruited and divided into two groups according to the BCVi obtained during anesthetic induction in each patient. Outcome analysis was conducted using data from 39 patients with a BCVi greater than 0 (BCVi > 0 group) and 27 with a BCVi of 0 (BCVi = 0 group). The primary outcome was a change in the value measured in the supine and lateral positions of the initially established BCP (BCPi; BCP at the time of BCVi injection), which was significantly larger in the BCVi > 0 group than in the BCVi = 0 group (1.5 (0.5-6.0) cmH2O vs. 0.0 (0.0-1.0) cmH2O; p < 0.001). BCVi was related to the left main bronchus (LMB) diameter (Spearman's rho = 0.676, p < 0.001) and the gap between the LMB diameter and the outer diameter of the bronchial cuff (Spearman's rho = 0.553, p < 0.001). Therefore, selecting a DLT size with a bronchial cuff that fits each patient's LMB may be useful in minimizing the change in BCP when performing lateral positioning during thoracic surgery. If the bronchial cuff requires unavoidable initial inflation, it is necessary to be aware that BCP may increase during lateral positioning and to monitor the BCP regularly if possible.

Assessment of the changes in cardiac sympathetic nervous activity using the pupil size changes measured in seated patients whose stellate ganglion is blocked by interscalene brachial plexus block.

BACKGROUND: As a side effect of interscalene brachial plexus block (ISBPB), stellate ganglion block (SGB) causes reductions in pupil size (Horner's syndrome) and cardiac sympathetic nervous activity (CSNA). Reduced CSNA is associated with hemodynamic instability when patients are seated. Therefore, instantaneous measurements of CSNA are important in seated patients presenting with Horner's syndrome. However, there are no effective tools to measure real-time CSNA intraoperatively. To evaluate the usefulness of pupillometry in measuring CSNA, we investigated the relationship between pupil size and CSNA. METHODS: Forty-two patients undergoing right arthroscopic shoulder surgery under ISBPB were analyzed. Pupil diameters were measured at 30 Hz for 2 s using a portable pupillometer. Bilateral pupil diameters and CSNA (natural-log-transformed low-frequency power [0.04-0.15 Hz] of heart rate variability [lnLF]) were measured before ISBPB (pre-ISBPB) and 15 min after transition to the sitting position following ISBPB (post-sitting). Changes in the pupil diameter ([right pupil diameter for post-sitting - left pupil diameter for post-sitting] - [right pupil diameter for pre-ISBPB - left pupil diameter for pre-ISBPB]) and CSNA (lnLF for post-sitting - lnLF for pre-ISBPB) were calculated. RESULTS: Forty-one patients (97.6%) developed Horner's syndrome. Right pupil diameter and lnLF significantly decreased upon transition to sitting after ISBPB. In the linear regression model (R2 =0.242, P=0.001), a one-unit decrease (1 mm) in the extent of changes in the pupil diameter reduced the extent of changes in lnLF by 0.659 ln(ms2/Hz) (95% CI [0.090, 1.228]). CONCLUSIONS: Pupillometry is a useful tool to measure changes in CSNA after the transition to sitting following ISBPB.

The Effects of Vasodilation Induced by Brachial Plexus Block on the Development of Postoperative Thrombosis of the Arteriovenous Access in Patients with End-Stage Renal Disease: A Retrospective Study.

Although brachial plexus block (BPB)-induced vasodilation reduces the incidence of arteriovenous access (AC) thrombosis, BPB cannot completely prevent its development. Therefore, we retrospectively investigated the factors affecting BPB-induced vasodilation and their effects on AC thrombosis development. Ninety-five patients undergoing AC surgery under BPB were analyzed. Vessel diameters were measured before and 20 min after BPB. The surgery abandoned before the BPB placement was performed when the BPB-induced increases in vessel diameters met its indications. Complete occlusive access thrombosis (COAT) was defined as loss of pulse, thrill, or bruit. Fourteen patients (14.7%) developed COAT. The outflow vein was more dilated by BPB than the inflow artery (0.6 versus 0.1 mm in median, p < 0.001). The original surgery plan was changed for seven patients (7.4%). Diabetes mellitus (DM) and ischemic heart disease (IHD) decreased the extent of increases in the inflow artery by -0.183 mm (95% confidence interval [CI] [-0.301, -0.065], p = 0.003) and outflow vein diameters by -0.402 mm (95% CI [-0.781, -0.024], p = 0.038), respectively. However, DM, IHD, and changes in the vessel diameters had insignificant effects on the development of COAT. In conclusion, although DM and IHD attenuate the vasodilating effects of BPB, they do not contribute to the development of COAT.

Comparison of Antinociceptive Properties Between Sevoflurane and Desflurane Using Pupillary Dilation Reflex Under Equivalent Minimum Alveolar Concentration: A Randomized Controlled Trial.

BACKGROUND: The pupillary dilation reflex (PDR), the change in pupil size after a nociceptive stimulus, has been used to assess antinociception during anesthesia. The aim of this study was to compare the antinociceptive properties of sevoflurane and desflurane by measuring the PDR amplitude. METHODS: Seventy patients between 20 and 55 years of age were randomly allocated to receive either sevoflurane or desflurane. The PDR amplitude after an electrical standardized noxious stimulation (SNT) was measured using an infrared pupillometer under 1.0 minimum alveolar concentration (MAC). The pupil diameter was measured from 5 seconds before to 5 minutes after the SNT. The mean arterial pressure (MAP), heart rate (HR), and bispectral index (BIS) were also measured immediately before and after SNT as well as 1 minute and 5 minutes after SNT. The primary outcome was the maximum percent increase from the prestimulation value of the pupil diameter, and the secondary outcomes were the maximum percent increase from the prestimulation value of the MAP, HR, and BIS after SNT. RESULTS: The maximum percent increase of the pupil diameter after SNT was not different between the 2 groups (median [first quartile to third quartile], 45.1 [29.3-80.3] vs 43.4 [27.0-103.1]; median difference, -0.3 [95% confidence interval, -16.0 to 16.5]; P = .986). Before SNT, the MAP was higher under 1.0 MAC of sevoflurane than desflurane; however, the maximum percent increase of MAP, HR, and BIS was not different between the 2 groups. CONCLUSIONS: The amount of change in the PDR amplitude, MAP, and HR after SNT was not different between sevoflurane and desflurane anesthesia. This result might suggest that sevoflurane and desflurane may not have different antinociceptive properties at equivalent MAC.

Awake nasotracheal intubation under bronchoscopic guidance and anesthetic management in a patient undergoing excision of an endotracheal mass: A case report.

RATIONALE: The main challenge facing anesthesiologists during endotracheal mass resection is securing effective airway management during surgery. It is important to select an airway intubation and airway maintenance method according to the patient's condition and the characteristics of the mass. PATIENT CONCERNS: A 74-year-old woman with aggravated dyspnea for 1 year was scheduled to undergo endotracheal mass excision under general anesthesia. DIAGNOSIS: The mass was 4 × 3 × 3 cm ovoid-shaped, and located 4 cm above the carina, occupying 41% of the tracheal lumen in a preoperative chest computed tomography and bronchoscopy. INTERVENTIONS: After preparing extracorporeal membrane oxygenation in case of the inability to ventilate and intubate, we attempted awake bronchoscopy-guided nasotracheal intubation using a reinforced endotracheal tube with an inner diameter of 5.5 mm and outer diameter of 7.8 mm after a translaryngeal block. The tube was passed around the mass without resistance and placed right above the carina. With the tube pulled back above the mass, another tube was introduced from the opened trachea below the mass to the right main bronchus. Following the resection of the tracheal portion containing the mass, the posterior wall of the remaining trachea was reconstructed. The tube placed in the right main bronchus was removed and the tube in the upper trachea was introduced right above the carina. The patient's head was kept flexed once the anastomosis of the trachea was completed, and the surgery ended uneventfully. OUTCOMES: The mass was confirmed as schwannoma by histopathological finding. The patient was discharged from the hospital on the 6th postoperative day without complication. LESSONS: Awake bronchoscopy-guided intubation is a safe airway management method in patients with an endotracheal mass. Close cooperation between anesthesiologist and surgeon, and preparation for airway management before surgery is essential. It is necessary to establish alternative plans that can be implemented in the case that intubation and ventilation are not possible.

Transparency considerations for describing statistical analyses in research.

Researchers who use the results of statistical analyses to draw conclusions about collected data must write a statistical analysis section in their manuscript. Describing statistical analyses in precise detail is as important as presenting the dosages of drugs and methodology of interventions. It is also essential for scientific accuracy and transparency in scientific research. We evaluated the quality of the statistical analysis sections of clinical research articles published in the Korean Journal of Anesthesiology between February 2020 and February 2021. Using a Likert scale where 1, 2, and 3 represented "not described at all," "partially described," and "fully described," respectively, the following 6 items were assessed: 1) stating of the statistical analysis methods used, 2) rationale for and detailed description of the statistical analysis methods used, 3) parameters derived from the statistical analyses, 4) type and version of the statistical software package used, 5) significance level, and 6) sidedness of the test (one-sided vs. two-sided). The first 3 items evaluate issues directly related to the statistical analysis methods used and last 3 are indirectly related items. In all the included articles, the statistical analysis methods used were stated (score of 3). However, only 4 articles (12.9%) fully described the sidedness of the test (score of 3). Authors tend not to describe the sidedness of statistical analysis tests in the methodology section of clinical research articles. It is essential that the sidedness be described in research studies.

Behavioral changes after hospital discharge in preschool children experiencing emergence delirium after general anesthesia: A prospective observational study.

BACKGROUND: Emergence delirium is well known as early postoperative behavioral change after general anesthesia. However, it is unclear whether children with emergence delirium have negative behavioral changes after hospital discharge. AIM: This observational study investigated the association between emergence delirium and posthospital behavioral changes. METHODS: One-hundred preschoolers aged 2-7 years undergoing elective surgery were enrolled in 2 tertiary university hospitals. Preoperative anxiety level was assessed using modified Yale preoperative anxiety scale. Emergence delirium was defined via pediatric anesthesia emergence delirium score ≥12 at any time in the recovery room. We divided the delirium score into a delirium-specific score (the sum of the first 3 items: eye contact, purposeful movement, and awareness of surrounding) and a pain-related score (the sum of the last 2 items: restlessness and inconsolability). High delirium scores represent severe emergence delirium. Posthospital behavioral changes were assessed by a change in Child Behavior Checklist 1.5-5 scores before and 1 week after surgery. The primary outcome was the total behavior checklist scores 1 week after surgery. Multiple linear regression was performed to identify risk factors for posthospital behavioral changes. RESULTS: Children with emergence delirium (n = 58) had higher postoperative behavior checklist scores than children without emergence delirium (n = 42) [mean (SD), 22.8 (17.5) vs. 14.0 (12.1); mean difference (95% CI), 8.8 (1.5-16.2)]. Increases in preoperative anxiety level [regression coefficient (b) (95% CI) =0.241 (0.126-0.356)] and peak delirium-specific score [b = 0.789 (0.137-1.442)] were associated with an increase in behavior checklist score 1 week after surgery, while pain-related score, type of surgery, premedication, and age were not. CONCLUSION: Children with emergence delirium developed more severe behavior changes 1 week after surgery than those without emergence delirium. High preoperative anxiety level and emergence delirium scores were associated with posthospital behavioral changes.

Changes in the Bronchial Cuff Pressure of Left-Sided Double-Lumen Endotracheal Tube by Lateral Positioning: A Prospective Observational Study.

Proper bronchial cuff pressure (BCP) is important when using a double-lumen endotracheal tube (DLT), especially in thoracic surgery. As positional change during endotracheal tube placement could alter cuff pressure, we aim to evaluate the change in BCP of DLT from the supine to the lateral decubitus position during thoracic surgery. A total of 69 patients aged 18-70 years who underwent elective lung surgery were recruited. BCP was measured at a series of time points in the supine and lateral decubitus positions after confirming the DLT placement. The primary outcome was change in the initial established BCP (BCPi), which is the maximum pressure at which the BCP did not exceed 40 cmH2O without air leak in the supine position, after lateral decubitus positioning. As the primary outcome, the BCPi increased from 25.4 ± 9.0 cmH2O in the supine position to 29.1 ± 12.2 cmH2O in the lateral decubitus position (p < 0.001). Out of the 69 participants, 43 and 26 patients underwent surgery in the left-lateral decubitus position (LLD group) and the right-lateral decubitus position (RLD group) respectively. In the LLD group, the BCPi increased significantly (p < 0.001) after lateral positioning and the beginning of surgery and the difference value, ∆BCPi, from supine to lateral position was significantly higher in the LLD group than in the RLD group (p = 0.034). Positional change from supine to lateral decubitus could increase the BCPi of DLT and the increase was significantly greater in LLD that in RLD.

Frontal electroencephalogram activity during emergence from general anaesthesia in children with and without emergence delirium.

BACKGROUND: Emergence delirium (ED) in children after general anaesthesia causes significant distress in patients, their family members, and clinicians; however, electroencephalogram (EEG) markers predicting ED have not been fully investigated. METHODS: This prospective, single-centre observational study enrolled children aged 2-10 yr old under sevoflurane anaesthesia. ED was assessed according to Diagnostic and Statistical Manual of Mental Disorders (DSM) IV or 5 criteria. The relative power of low-frequency (delta and theta) and high-frequency (alpha and beta) EEG waves during the emergence period was compared between the children with and without ED. The linear relationships between the relative power and peak Paediatric Assessment of Emergence Delirium (PAED) score were investigated. RESULTS: Among the 60 patients, 22 developed ED (ED group), whereas the other 38 did not (non-ED group). The relative power of the delta wave was higher (mean [standard deviation], 0.579 [0.083] vs 0.453 [0.090], respectively, P<0.001) in the ED group, whereas that of the alpha and beta waves was lower in the ED group, than in the non-ED group (0.155 [0.063] vs 0.218 [0.088], P=0.005 and 0.114 [0.069] vs 0.186 [0.070], P<0.001, respectively). The areas under the receiver operating characteristic curves of the relative power of the delta wave, low-to-high frequency power ratio, and delta-to-alpha ratio were 0.837 (95% confidence interval, 0.737-0.938), 0.835 (0.735-0.934), and 0.768 (0.649-0.887), respectively. The relative power of the delta wave and the two ratios had a positive linear relationship with the peak PAED scores. CONCLUSIONS: Paediatric patients developing ED have increased low-frequency (delta) frontal EEG activity with reduced high-frequency (alpha and beta) activity during emergence from general anaesthesia. CLINICAL TRIAL REGISTRATION: NCT03797274.

Modeling of driver's collision avoidance maneuver based on controller switching model.

This paper presents a modeling strategy of human driving behavior based on the controller switching model focusing on the driver's collision avoidance maneuver. The driving data are collected by using the three-dimensional (3-D) driving simulator based on the CAVE Automatic Virtual Environment (CAVE), which provides stereoscopic immersive virtual environment. In our modeling, the control scenario of the human driver, that is, the mapping from the driver's sensory information to the operation of the driver such as acceleration, braking, and steering, is expressed by Piecewise Polynomial (PWP) model. Since the PWP model includes both continuous behaviors given by polynomials and discrete logical conditions, it can be regarded as a class of Hybrid Dynamical System (HDS). The identification problem for the PWP model is formulated as the Mixed Integer Linear Programming (MILP) by transforming the switching conditions into binary variables. From the obtained results, it is found that the driver appropriately switches the "control law" according to the sensory information. In addition, the driving characteristics of the beginner driver and the expert driver are compared and discussed. These results enable us to capture not only the physical meaning of the driving skill but the decision-making aspect (switching conditions) in the driver's collision avoidance maneuver as well.