A model study for the classification of high-risk groups for cardiac arrest in general ward patients using simulation techniques.

Currently, many hospitals use vital signs-based criteria such as modified early warning score (MEWS) and national early warning score (NEWS) to classify high-risk patients for cardiac arrest, but there are limitations in selecting high-risk patients with a possibility of cardiac arrest. The purpose of this study is to develop a cardiac arrest classification model to identify patients at high risk of cardiac arrest based on the patient family and past history, and blood test results after hospitalization, rather than vital signs. This study used electronic medical record (EMR) data from A university hospital, and patients in the high-risk group for cardiac arrest were defined as those who underwent cardio-pulmonary resuscitation (CPR) after cardiac arrest. Considering the use of the rapid response team of A university hospital, patients hospitalized in intensive care units (ICU), emergency medicine departments, psychiatric departments, pediatric departments, cardiology departments, and palliative care wards were excluded. This study included 325,534 patients, of which 3291 low-risk and 382 high-risk patients were selected for study. Data were split into training and validation data sets and univariate analysis was performed for 13 candidate risk factors. Then, multivariate analysis was performed using a bivariate logistic regression model, and an optimal model was selected using simulation analysis. In the training data set, it was calculated as sensitivity 75.25%, precision 21.59%, specificity 66.89%, accuracy 67.79%, F1 score 33.56, area under curve (AUC) 71.1 (95% confidence interval [CI] = 68.9-73.1 P value=<.001). In the validation data set, sensitivity 73.37%, precision 25.81%, specificity 75.03%, accuracy 74.86%, F1 score 38.19, AUC 74.2 (95% CI = 72.1-76.2, P value=<.001) were calculated. A model for classifying the high-risk group of cardiac arrest should be developed from various perspectives. In the future, in order to classify patients with high risk of cardiac arrest, a prospective study on the combined use of the model developed by this study and NEWS or MEWS should be conducted.

Local anesthetic volume in ultrasound-guided interscalene block and opioid consumption during shoulder arthroscopic surgery: A retrospective comparative study.

ABSTRACT: Interscalene block (ISB) is commonly performed for regional anesthesia in shoulder surgery. Ultrasound-guided ISB enables visualization of the local anesthetic spread and a reduction in local anesthetic volume. However, little is known about the appropriate local anesthetic dose for surgical anesthesia without sedation or general anesthesia. The purpose of our study was to evaluate the appropriate local anesthetic volume by comparing intraoperative analgesics and hemodynamic changes in ISB in arthroscopic shoulder surgery.Overall, 1007 patients were divided into groups 1, 2, and 3 according to the following volume of local anesthetics: 10-19, 20-29, and 30-40 mL, respectively. The use of intraoperative analgesics and sedatives, and the reduction in intraoperative maximum blood pressure and heart rate were compared through retrospective analysis.Fentanyl was used in 55.6% of patients in group 1, which was significantly higher than in those groups 2 and 3 (22.3% and 30.7%, respectively); furthermore, it was also higher than those in groups 2 and 3 in dose-specific comparisons (P < .05). The percent of the maximum reduction in intraoperative systolic blood pressure and heart rate in group 3 was significantly higher than those in groups 1 and 2. Ephedrine administration was lower in group 2 than that in other groups (P < .05). The incidence of hypotensive bradycardic events was lowest (9.1%) at the local anesthetic volume of 24 mL as revealed by the quadratic regression analysis (R2 = 0.313, P = .003).Decreasing the local anesthetic volume to less than 20 mL for ultrasound-guided ISB as the sole anesthesia increases the opioid consumption during shoulder arthroscopic surgery. Local anesthetics >30 mL or increased opioid consumption with <20 mL of local anesthetics could increase the risk of cardiovascular instability intraoperatively. Our findings indicate that 24 mL of local anesthetic could be used to lower the incidence of hypotensive bradycardic events.

Effect of a mother's recorded voice on emergence from general anesthesia in pediatric patients: study protocol for a randomized controlled trial.

BACKGROUND: Emergence delirium is a behavioral disturbance after general anesthesia in children and may distress both the patients and the primary caregivers, such as parents and medical staff, looking after the patients. Various medical and emotional interventions have been investigated to reduce emergence delirium; however, none are completely effective. This trial intends to assess whether the mother's recorded voice can reduce this adverse post-anesthesia event and facilitate arousal from general anesthesia. METHODS/DESIGN: This is a prospective, double-blind, single-center, parallel-arm, superiority, randomized controlled trial to be conducted in participants aged 2-8 years who are undergoing elective surgery requiring general anesthesia. Participants will be randomly assigned to one of two groups: those who are stimulated to wake up by listening to their mother's recorded voice (maternal group, n = 33) or a stranger's voice (stranger group, n = 33) during anesthetic emergence. The primary outcome is the initial emergence delirium score in the post-anesthesia care unit (PACU). The secondary outcomes are hemodynamic parameters, including heart rate and mean blood pressure, the duration of time between the cessation of anesthetics and a BIS level of 60, 70 and 80, eye-opening or purposeful movement time, extubation time, total consumption of analgesics, PACU stay time, emergence delirium and pain scores during the PACU stay. DISCUSSION: This is the first randomized controlled trial to investigate the effect of a mother's recorded voice during emergence on the pediatric emergence profile after general anesthesia. It may provide prophylactic treatment options to decrease emergence delirium and enhance arousal from general anesthesia. TRIAL REGISTRATION: ClicnicalTrials.gov, ID: NCT02955680 . Registered on 2 November 2016.

Perioperative management of left ventricular diastolic dysfunction and heart failure: an anesthesiologist's perspective.

Anesthesiologists frequently see asymptomatic patients with diastolic dysfunction or heart failure for various surgeries. These patients typically show normal systolic function but abnormal diastolic parameters in their preoperative echocardiographic evaluations. The symptoms that are sometimes seen are similar to those of chronic obstructive pulmonary disease. Patients with diastolic dysfunction, and even with diastolic heart failure, have the potential to develop a hypertensive crisis or pulmonary congestion. Thus, in addition to conventional perioperative risk quantification, it may be important to consider the results of diastolic assessment for predicting the postoperative outcome and making better decisions. If anesthesiologists see female patients older than 70 years of age who have hypertension, diabetes, chronic renal disease, recent weight gain, or exercise intolerance, they should focus on the patient's diastologic echocardiography indicators such as left atrial enlargement or left ventricular hypertrophy. In addition, there is a need for perioperative strategies to mitigate diastolic dysfunction-related morbidity. Specifically, hypertension should be controlled, keeping pulse pressure below diastolic blood pressure, maintaining a sinus rhythm and normovolemia, and avoiding tachycardia and myocardial ischemia. There is no need to classify these diastolic dysfunction, but it is important to manage this condition to avoid worsening outcomes.

Changes in heart rate variability after sitting following interscalene block.

PURPOSE: Hypotensive bradycardic events (HBEs) occur in 5-28% of patients undergoing arthroscopic shoulder surgery in the sitting position after an interscalene brachial plexus block (ISBPB). The objective of this study was to investigate the effects of the sitting position following ISBPB on heart rate variability (HRV). METHODS: In this prospective case-control study, we evaluated 64 patients undergoing arthroscopic shoulder surgery under ISBPB and 49 nonsurgical control subjects. HRV power spectral analysis parameters were measured (and natural log-transformed) before ISBPB and after changing to the sitting position. The patients experiencing HBEs were assigned to the HBE group, and the remaining patients were assigned to the non-HBE group. RESULTS: HBEs developed in 18 patients (28.1%). Changing from the supine position to the sitting position after ISBPB did not induce a significant increase in the natural log-transformed ratio of low-frequency to high-frequency power (lnLF/HF). A significant decrease in natural log-transformed high-frequency power (lnHF) was observed compared to the control group, who presented a significant increase in lnLF/HF and an insignificant change in lnHF. lnHF was found to be significantly higher in the HBE group compared to the non-HBE group. CONCLUSIONS: Sustained vagal activity with a failed shift in the sympathovagal balance toward sympathetic predominance in response to sitting after ISBPB is associated with the development of HBE.

Adsorption of desflurane by the silica gel filters in breathing circuits: an in vitro study.

BACKGROUND: During general anesthesia, a heated breathing circuit (HBC) is used to replace the heat and moisture exchange function of the upper airway. One HBC uses an air dryer filter that employs silica gel (SG) as a desiccant. SG is capable of adsorbing many organic compounds. Therefore, we undertook an in vitro study of the adsorption of desflurane by SG filters. METHODS: An HBC was connected to an anesthesia machine, and a test lung was connected to the circuit. The test lung was mechanically ventilated with 2 or 4 L/min of fresh gas flow, with and without the air dryer filter. Desflurane was administered at a 6 vol% on the vaporizer dial setting. The experiment was repeated 15 times in each group. The end-tidal concentrations were measured during the experiments. The air dryer filter weights were measured before and after the experiments, and the times required to achieve the specific end-tidal desflurane concentrations were determined. RESULTS: Significant differences in the end-tidal concentrations of desflurane were observed between the control and filter groups (P < 0.001). The filter weights increased significantly after the experiments (P < 0.001). The times required to achieve the same end-tidal desflurane concentrations were different with the application of the air dryer filter (P < 0.001). CONCLUSIONS: The adsorption of desflurane with the use of an air dryer filter was verified in this in vitro study. Careful attention is needed when using air dryer gel filters during general anesthesia.

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.

Role of calcium channels responsible for phenylephrine-induced contraction in rat aorta 3 days after acute myocardial infarction.

BACKGROUND: Phenylephrine (PE) produces tonic contraction through involvement of various calcium channels such as store-operated calcium channels (SOCCs) and voltage-operated calcium channels (VOCCs). However, the relative contribution of each calcium channel to PE-induced contraction has not been investigated in isolated rat aorta of early acute myocardial infarction (AMI). METHODS: Endothelium-denuded rat aortic rings from rats 3 days after AMI or sham-operated (SHAM) rats were prepared in an organ chamber with Krebs-Ringer bicarbonate solution for isometric tension recording. We assessed the PE dose-response relationships in 2.5 mM calcium medium for both groups. The same procedure was repeated using rings pretreated with the SOCC inhibitor 2-aminoethoxydiphenyl borate, sarco/endoplasmic-reticulum calcium ATPase inhibitor thapsigargin (TG), diacyl glycerol lipase inhibitor RHC80267, and sodium-calcium exchanger inhibitor 3,4-dichlorobenzamil hydrochloride for 30 minutes before addition of calcium. When ongoing tonic contraction was sustained, dose-response curves to the VOCC inhibitor nifedipine were obtained to assess the relative contribution of each calcium channel under various conditions. RESULTS: The effect of SOCC induction with TG pretreatment on PE-induced contraction was significantly lower in the AMI group compared to the SHAM group. In addition, there were significant decreases in the sensitivity and efficacy of the VOCC inhibitor nifedipine on PE-induced contraction in the AMI group. CONCLUSIONS: Results suggest that the change of vascular reactivity of PE in rat aorta 3 days after AMI is characterized by a decreased contribution of L-type VOCCs. The enhanced VOCC-independent calcium entry mechanisms after AMI can be mediated by enhanced capacitative calcium entry through the activation of SOCCs.

Moderate hypothermia attenuates α(1)-adrenoceptor-mediated contraction in isolated rat aorta: the role of the endothelium.

Moderate hypothermia (25-31 °C) may have a significant influence on vascular tone. We investigated the cellular mechanisms by which moderate hypothermia alters α-adrenoceptor-mediated contraction in rat thoracic aortae. Cyclooxygenase inhibition by indomethacin; nitric oxide (NO) synthase inhibition by L-NAME; potassium channel and endothelium-derived hyperpolarizing factor (EDHF) inhibition by glibenclamide and TEA; G protein inhibition by pertussis toxin; α2-adrenergic inhibition by yohimbine; and ß-adrenergic inhibition by propranolol were assessed for their effect on the contractile response to the α1-adrenoceptor agonist phenylephrine (Phe) in combination with moderate hypothermia (25 °C). Moderate hypothermia produced a shift to the right for the Phe concentration-response curves in endothelium-intact (E+) and endothelium-denuded (E-) aortic rings. The maximal response to Phe in E+ rings was significantly decreased (P<0.05) at 25 °C compared to 38 °C, whereas there was no significant difference in E- rings. Hypothermia-induced vasorelaxation in E+ rings was attenuated (P<0.05) following combined pretreatment with L-NAME (10⁻4 M) and indomethacin (10⁻5 M), whereas other inhibitors had no significant effect. Importantly, the addition of TEA to rings that were pretreated with L-NAME and indomethacin exhibited no further attenuation (P>0.05) of hypothermia-induced vasorelaxation. The concentrations of cGMP and cAMP, as measured by radioimmunoassay, were significantly increased (P<0.05) in E+ rings at 25 °C compared to those at 38 °C, whereas there were no significant differences (P>0.05) in E- rings. The present study demonstrated that rat aortic endothelium is stimulated during moderate hypothermia and that the NO-cGMP and prostacyclin (PGI2)-cAMP pathways represent endothelium-dependent mechanisms of hypothermia-induced vasorelaxation. In contrast, EDHF may not be associated with hypothermia-induced vasorelaxation.

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.

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 provider's 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 Student's t-test and Pearson's 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 provider's 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: Provider's level of experience and the distance from skin to subarachnoid or epidural space influenced the difficulty in performing a neuraxial blockade.

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.

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.

The perioperative management of a patient with lowe syndrome for general anesthesia: A case report.

Lowe syndrome (the oculo-cerebro-renal syndrome of Lowe, OCRL) is a multi-system disorder that affects the eyes, nervous system, and kidney. OCRL is a rare X-linked recessive disease with a prevalence of approximately 1 : 500,000. The clinical features of OCRL include congenital cataracts, growth and mental retardation, areflexia, hypotonia, and renal tubular dysfunction (Fanconi-type). Chronic metabolic acidosis and hypotonia may be the most important component affecting management of the peri-anesthetic period during general anesthesia. However, problems such as electrolyte imbalance, seizure, fragility of the bone structures, and increased intraocular pressure should also be considered during the perioperative period. We report here the perioperative management of a patient with Lowe syndrome during the removal of multiple scalp cysts under general anesthesia.

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.