Erector spinae plane block level does not impact analgesic efficacy in enhanced recovery for lumbar spine surgery.

BACKGROUND CONTEXT: Postoperative pain control following spine surgery can be difficult. The Enhanced Recovery After Surgery (ERAS) programs use multimodal approaches to manage postoperative pain. While an erector spinae plane block (ESPB) is commonly utilized, the ideal distance for injection from the incision, referred to as the ES (ESPB to mid-surgical level) distance, remains undetermined. PURPOSE: We evaluated the impact of varying ES distances for ESPB on Numerical Rating Scale (NRS) measures of postoperative pain within the ERAS protocol. STUDY DESIGN/SETTING: Retrospective observational study. PATIENT SAMPLE: Adult patients who underwent elective lumbar spine fusion surgery. OUTCOME MEASURES: Primary outcome measures include the comparative postoperative NRS scores across groups at immediate (T1), 24 (T2), 48 (T3), and 72 (T4) hours postsurgery. For secondary outcomes, a propensity matching analysis compared these outcomes between the ERAS and non-ERAS groups, with opioid-related recovery metrics also assessed. METHODS: All included patients were assigned to one of three ERAS groups according to the ES distance: Group 1 (G1, ES > 3 segments), Group 2 (G2, ES = 2-3 segments), and Group 3 (G3, ES<2 segments). Each patient underwent a bilateral ultrasound-guided ESPB with 60 mL of diluted ropivacaine or bupivacaine. RESULTS: Patients within the ERAS cohort reported mild pain (NRS < 3), with no significant NRS variation across G1 to G3 at any time. Sixty-five patients were matched across ERAS and non-ERAS groups. The ERAS group exhibited significantly lower NRS scores from T1 to T3 than the non-ERAS group. Total morphine consumption during hospitalization was 26.7 mg for ERAS and 41.5 mg for non-ERAS patients. The ERAS group resumed water and food intake sooner and had less postoperative nausea and vomiting. CONCLUSIONS: ESPBs can be effectively administered at or near the mid-surgical level to the low thoracic region for lumbar spine surgeries. Given challenges with sonovisualization, a lumbar ESPB may be preferred to minimize the risk of inadvertent pleural injury.

Analgesia-nociception index accurately predicts inadequate pectoralis muscle fascia block (PECS) in patients undergoing breast surgery: A prospective observational study.

BACKGROUND: Postoperative opioid administration has been largely replaced by regional anesthesia techniques. We aimed to determine whether intraoperative Analgesia-Nociception Index (ANI) can aid in early evaluation of the effectiveness of regional blocks such as the pectoralis muscle fascia block (PECS, pectoserratus and interpectoral plane blocks) and predicting the need for analgesics postoperatively. METHODS: This prospective observational study enrolled 30 women (age: 20-80 years) undergoing unilateral, non-intubated, breast tumor excision alone or in conjunction with sentinel lymph node biopsy. PECS block was performed following sedation. ANI readings were obtained at 1-min intervals, and polar coordinates were assigned to the distance from the nipple (0.5-cm intervals) and o'clock position (15-min intervals) for each reading. Pain scores were assessed using a numeric rating scale from 0 to 10, and analgesics were administered depending on pain score post-operatively. RESULTS: 8 (27%), 19 (63%), and 3 (10%) patients received morphine, tramadol, and no analgesics, respectively. In total, 954 ANI measurements were obtained. At the proposed cut-off of 50, the sensitivity and specificity of the ANI nadir for need of post-operative opioids were 0.875 and 0.932, respectively. Block effectiveness was most satisfactory in the upper lateral quadrant of the breast with nipple-areolar complex (NAC) sparing effect. Most average ANI measurements for the NAC were <50. No patient experienced postoperative nausea/vomiting, although one reported dizziness. CONCLUSIONS: The intraoperative ANI nadir <50 was strongly correlated with need for postoperative opioids. The ANI may aid in objectively evaluating the effectiveness of pectoralis muscle fascial blocks and predicting postoperative need for analgesics.

Sugammadex shortens operation time and improves operation turnover efficacy in video-assisted thoracoscopic surgery.

BACKGROUND: This study compared sugammadex and neostigmine as agents for routine neuromuscular blockade reversal in video-assisted thoracoscopic surgery (VATS) to determine the optimal choice that achieves a shorter operation time and improved turnover efficiency while enhancing postoperative outcomes and ensuring patient safety during thoracic surgery. METHODS: This prospective study, conducted from July 2022 to March 2023, compared the effect of sugammadex and neostigmine on operation time and turnover efficiency in VATS, involving 60 participants randomly assigned to either group, with the primary objective of identifying the optimal anesthesia reversal choice for improved outcomes and patient safety during thoracic surgery. RESULTS: In the study, the sugammadex group showed a significantly shorter total operation room occupancy time (130 ± 7 vs 157 ± 7 minutes; p = 0.009) than the neostigmine group. Patients in the neostigmine group had higher mean pulse rates when leaving the operation room (85 ± 3 vs 73 ± 3 beats/min; p = 0.002) and 120 minutes later in the postanesthesia care unit (76 ± 2 vs 68 ± 2; p = 0.016). CONCLUSION: This study's findings suggest that sugammadex may enhance total operating room occupancy time, operation turnover efficacy, and respiratory recovery outcomes in VATS, potentially improving patient care and anesthesia management.

Logistic Regression Is Non-Inferior to the Response Surface Model in Patient Response Prediction of Video-Assisted Thoracoscopic Surgery.

Response surface models (RSMs) are a new trend in modern anesthesia. RSMs have demonstrated significant applicability in the field of anesthesia. However, the comparative analysis between RSMs and logistic regression (LR) in different surgeries remains relatively limited in the current literature. We hypothesized that using a total intravenous anesthesia (TIVA) technique with the response surface model (RSM) and logistic regression (LR) would predict the emergence from anesthesia in patients undergoing video-assisted thoracotomy surgery (VATS). This study aimed to prove that LR, like the RSM, can be used to improve patient safety and achieve enhanced recovery after surgery (ERAS). This was a prospective, observational study with data reanalysis. Twenty-nine patients (American Society of Anesthesiologists (ASA) class II and III) who underwent VATS for elective pulmonary or mediastinal surgery under TIVA were enrolled. We monitored the emergence from anesthesia, and the precise time point of regained response (RR) was noted. The influence of varying concentrations was examined and incorporated into both the RSM and LR. The receiver operating characteristic (ROC) curve area for Greco and LR models was 0.979 (confidence interval: 0.987 to 0.990) and 0.989 (confidence interval: 0.989 to 0.990), respectively. The two models had no significant differences in predicting the probability of regaining response. In conclusion, the LR model was effective and can be applied to patients undergoing VATS or other procedures of similar modalities. Furthermore, the RSM is significantly more sophisticated and has an accuracy similar to that of the LR model; however, the LR model is more accessible. Therefore, the LR model is a simpler tool for predicting arousal in patients undergoing VATS under TIVA with Remifentanil and Propofol.

True intratracheal oxygen concentration delivered by SentriO Oxy™ masks under various respiratory conditions: a bench study.

SentriO Oxy™ is a newly available, Food and Drug Administration-approved oxygenation mask system that provides high oxygenation, even on low-flow (5-10 L/min) oxygen. This study aimed to accurately measure the intratracheal fraction of inspired oxygen (FiO2) using SentriO Oxy™ masks under relatively low oxygen flow rates. A manikin-ventilator-test lung simulation system was used. We measured FiO2 at the level of the carina, 5 minutes after applying 45 different respiratory parameter combinations using SentriO Oxy™ masks. Tidal volume (TV) was set to 300, 500, and 700 mL; respiratory rate (RR) was set to 8, 12, 16, 20, and 24 breaths per minute; and oxygen flow rate was set to 6, 8, and 10 L/min. Our hypothesis was that FiO2 would be proportional to the difference between oxygen flow rate and minute ventilation. FiO2 measured by smaller TV, lower RR, or higher oxygen flows revealed a significantly higher value, confirming our hypothesis. In addition, using linear regression analysis, we found that TV, RR, and oxygen flow were all significant factors influencing the measured FiO2. Our experiment proposed two prediction equations considering the oxygen flow rate, TV, and RR. The results of our study may provide information and prediction of FiO2 for clinicians to use SentriO Oxy™ masks during sedative anesthetic procedures under low oxygen flow rates.

Total intravenous anesthesia decreases hospital stay but not incidence of postoperative pulmonary complications after lung resection surgery: a propensity score matching study.

BACKGROUND: There is no consensus regarding the superiority of volatile or total intravenous anesthesia (TIVA) in reducing the incidence of postoperative pulmonary complications (PPCs) after lung resection surgery (LRS). Thus, the aim of this study was to investigate the different anesthetic regimens and the incidence of PPCs in patients who underwent LRS. We hypothesized that TIVA is associated with a lower incidence of PPCs than volatile anesthesia. METHODS: This was a retrospective cohort study of patients who underwent LRS at Taipei Veterans General Hospital between January 2016 and December 2020. The patients' charts were reviewed and data on patient characteristics, perioperative features, and postoperative outcomes were extracted and analyzed. The patients were categorized into TIVA or volatile anesthesia groups and their clinical data were compared. Propensity score matching was performed to reduce potential selection bias. The primary outcome was the incidence of PPCs, whereas the secondary outcomes were the incidences of other postoperative events, such as length of hospital stay (LOS) and postoperative nausea and vomiting (PONV). RESULTS: A total of 392 patients each were included in the TIVA and volatile anesthesia groups. There was no statistically significant difference in the incidence of PPCs between the volatile anesthesia and TIVA groups. The TIVA group had a shorter LOS (p < 0.001) and a lower incidence of PONV than the volatile anesthesia group (4.6% in the TIVA group vs. 8.2% in the volatile anesthesia group; p = 0.041). However, there were no significant differences in reintubation, 30-day readmission, and re-operation rates between the two groups. CONCLUSIONS: There was no significant difference between the incidence of PPCs in patients who underwent LRS under TIVA and that in patients who underwent LRS under volatile anesthesia. However, TIVA had shorter LOS and lower incidence of PONV which may be a better choice for maintenance of anesthesia in patients undergoing LRS.

Arterial blood pressure waveform in liver transplant surgery possesses variability of morphology reflecting recipients' acuity and predicting short term outcomes.

We investigated clinical information underneath the beat-to-beat fluctuation of the arterial blood pressure (ABP) waveform morphology. We proposed the Dynamical Diffusion Map algorithm (DDMap) to quantify the variability of morphology.  The underlying physiology could be the compensatory mechanisms involving complex interactions between various physiological mechanisms to regulate the cardiovascular system. As a liver transplant surgery contains distinct periods, we investigated its clinical behavior in different surgical steps. Our study used DDmap algorithm, based on unsupervised manifold learning, to obtain a quantitative index for the beat-to-beat variability of morphology. We examined the correlation between the variability of ABP morphology and disease acuity as indicated by Model for End-Stage Liver Disease (MELD) scores, the postoperative laboratory data, and 4 early allograft failure (EAF) scores. Among the 85 enrolled patients, the variability of morphology obtained during the presurgical phase was best correlated with MELD-Na scores. The neohepatic phase variability of morphology was associated with EAF scores as well as postoperative bilirubin levels, international normalized ratio, aspartate aminotransferase levels, and platelet count. Furthermore, variability of morphology presents more associations with the above clinical conditions than the common BP measures and their BP variability indices. The variability of morphology obtained during the presurgical phase is indicative of patient acuity, whereas those during the neohepatic phase are indicative of short-term surgical outcomes.

Opioid-sparing anesthesia with dexmedetomidine provides stable hemodynamic and short hospital stay in non-intubated video-assisted thoracoscopic surgery: a propensity score matching cohort study.

OBJECTIVES: Dexmedetomidine is an alpha-2 agonist with anti-anxiety, sedative, and analgesic effects and causes a lesser degree of respiratory depression. We hypothesized that the use of dexmedetomidine in non-intubated video-assisted thoracic surgery (VATS) may reduce opioid-related complications such as postoperative nausea and vomiting (PONV), dyspnea, constipation, dizziness, skin itching, and cause minimal respiratory depression, and stable hemodynamic status. METHODS: Patients who underwent non-intubated VATS lung wedge resection with propofol combined with dexmedetomidine (group D) or alfentanil (group O) between December 2016 and May 2022 were enrolled in this retrospective propensity score matching cohort study. Intraoperative vital signs, arterial blood gas data, perioperative results and treatment outcomes were analyzed. Of 100 patients included in the study (group D, 50 and group O, 50 patients), group D had a significantly lower degree of decrement in the heart rate and the blood pressure than group O. Intraoperative one-lung arterial blood gas revealed lower pH and significant ETCO2. The common opioid-related side effects, including PONV, dyspnea, constipation, dizziness, and skin itching, all of which occurred more frequently in group O than in group D. Patients in group O had significantly longer postoperative hospital stay and total hospital stay than group D, which might be due to opioid-related side effects postoperatively. CONCLUSIONS: The application of dexmedetomidine in non-intubated VATS resulted in a significant reduction in perioperative opioid-related complications and maintenance with acceptable hemodynamic performance. These clinical outcomes found in our retrospective study may enhance patient satisfaction and shorten the hospital stay.

Pharmacodynamic modeling of moderate sedation and rationale for dosing using midazolam, propofol and alfentanil.

PURPOSE: Regulations have broadened to allow moderate sedation administration for gastrointestinal endoscopy by non-anesthesia personnel. The line between moderate and deep sedation is ambiguous. Deep sedation offers patient comfort as well as greater safety concerns. Unintended deep sedation can occur if drug interactions are overlooked. We present a pharmacodynamic model for moderate sedation using midazolam, alfentanil and propofol. The model is suitable for training and devising rationales for appropriate dosing. METHODS: The study consists of two parts: modeling and validation. In modeling, patients scheduled for esophagogastroduodenoscopy (EGD) or colonoscopy sedation are enrolled. The modified observer's assessment of alertness/sedation (MOAA/S) score < 4 is defined as loss of response to represent moderate sedation. Two patient groups receiving bronchoscopy or endoscopic retrograde cholangiopancreatography (ERCP) are used for validation. Model performance is assessed by receiver operating characteristic (ROC) curves and area under the curve (AUC). Simulations are performed to demonstrate how the model is used to rationally determine drug regimen for moderate sedation. RESULTS: Interaction between propofol and alfentanil is stronger than the other pairwise combinations. Additional synergy is observed with three drugs. ROC AUC is 0.83 for the modeling group, and 0.96 and 0.93 for ERCP and bronchoscopy groups respectively. Model simulation suggests that 1 mg midazolam, 250 µg alfentanil and propofol maximally benefits from drug interactions and suitable for moderate sedation. CONCLUSION: We demonstrate the accurate prediction of a three-drug response surface model for moderate sedation and simulation suggests a rational dosing strategy for moderate sedation with midazolam, alfentanil and propofol.

Simulation-Based Gastrointestinal Endoscopy Sedations: A Novel Validation to Multidrug Pharmacodynamic Modeling.

Pharmacodynamic models have described the interactions between anesthetics. Applying the models to clinical practice is still problematic due to inherent limitations: 1. modeling conditions are different from practice. 2. One model can only describe one endpoint. To tackle these, we propose a new method of model validation for recovery and intraprocedural sedation adequacy with a three-drug pharmacodynamic model using six published clinical studies that contain midazolam, opioid, and propofol. Mean drug dose, intraprocedural sedation level, procedure, and recovery time are extracted from each study. Simulated drug regimens are designed to best approximate study conditions. A published deep sedation model is used for simulation. Model-predicted recovery time and intraprocedural sedation scores are compared with the original clinical study outcomes. The model successfully predicted recovery times in eight out of nine regimens. Lower doses of midazolam are associated with faster recovery. Model prediction of intraprocedural sedation level was compatible with the clinical studies in five out of seven regimens. The three-drug pharmacodynamic model describes the course of gastrointestinal endoscopy sedations from clinical studies well. Model predictions are consistent with the results from clinical studies. The approach implies that large scale validation can be performed repeatedly.

Response surface model comparison and combinations for remifentanil and propofol in describing response to esophageal instrumentation and adverse respiratory events.

BACKGROUND: The primary aim of this essay was to explore the best fitting model in remifentanil-propofol combined administrations during esophageal instrumentation (EI) from five distinct response surface models. The secondary aim was to combine the models to give appropriate effect-site drug concentrations (Ces) range with maximal comfort and safety. METHODS: The Greco, reduced Greco, Minto, Scaled C50 Hierarchy and Fixed C50 Hierarchy models were constructed to fit four drug effects: loss of response to esophageal instrumentation (LREI), loss of response to esophageal instrumentation revised (LREIR), intolerable ventilatory depression (IVD) and respiratory compromise (RC). Models were tested by chi-square statistical test and evaluated with Akaike Information Criterion (AIC). Model prediction performance were measured by successful prediction rate (SPR) and three prediction errors. RESULTS: The reduced Greco model was the best fitting model for LREI and RC, and the Minto model was the best fitting model for LREIR and IVD. The SPRs of reduced Greco model for LREI and RC were 81.76% and 79.81%. The SPRs of Minto model for LREIR and IVD were 80.32% and 80.12%. Overlay of the reduced Greco model for LREI and Minto model for IVD offered visual aid for guidance in drug administration. CONCLUSION: Using proper response surface model to fit different drug effects will describe the interactions between anesthetic drugs better. Combining response surface models to select the more reliable effect-site drug concentrations range can be used to guide clinical drug administration with greater safety and provide an improvement of anesthesia precision.

Improvement in vocal-cord visualization with Trachway video intubating stylet using direct oxygen flow and effective analysis of the fraction of inspired oxygen: a bench study.

The Trachway video intubating stylet device facilitates the visualization of the airways of patients from the tip of an endotracheal tube (ETT) during intubation. The major limitations of Trachway are the restricted view due to secretions and the risk of a prolonged apnea during intubation. We conducted a bench study to verify the performance of an alternative, easily applicable airway device that allows better visualization of trackways during Trachway-assisted intubation and prevents the detrimental effects of apnea-related hypoxia. We conducted a bench study to thoroughly evaluate the oral-secretion-elimination ability of a newly designed oxygen delivery device (ODD) to improve vocal-cord visualization using the three commonly used ETT sizes (i.e., 7, 7.5, and 8 mm). Moreover, we measured the fraction of inspired oxygen (FiO2) under different, continuous oxygen-flow supplies (1-10 L/min) during intubation. Each condition was analyzed for a 2 min video-stylet-intubation period. The supplemental oxygen flow and FiO2 fraction achieved using our ODD were higher, and smaller ETTs exhibited better secretion elimination. The ODD, which can be easily coupled with Trachway stylets, enabled high-quality visualization during oxygen flows of 6-8 L/min, and higher FiO2 fractions were achieved at higher oxygen flow rates. The use of the ODD improved the visualization of the airways during video stylet-assisted intubations using the additional FiO2 supply. The ODD developed in this study improves the visualization of airways with Trachway stylets and enhances the safety of intubation.

Needle-Probe Optical Coherence Tomography for Real-Time Visualization of Veress Peritoneal Needle Placement in a Porcine Model: A New Safety Concept for Pneumoperitoneum Establishment in Laparoscopic Surgery.

The safe establishment of pneumoperitoneum is a critical step in all laparoscopic surgeries. A closed pneumoperitoneum is usually obtained by inserting a Veress needle into the peritoneal cavity. However, there is no definite measure to visually confirm the position of the Veress needle tip inside the peritoneal cavity. This study aimed to describe a method of real-time visual detection of peritoneal placement of the Veress needle using an incorporated optical coherence tomography (OCT) probe in a porcine model. A 14-gauge Veress needle was incorporated with a miniature fiber probe to puncture the piglet's abdominal wall into the peritoneal cavity. A total of 80 peritoneal punctures were attempted in four piglets. For each puncture, continuous two-dimensional OCT images of the abdominal wall were acquired for real-time visual detection of the needle placement into the peritoneal cavity. Characteristic OCT image patterns could be observed during the puncturing process, especially a deep V-shaped concave pattern before the peritoneum puncture, which was a crucial feature. A statistical difference in the OCT signal standard deviation value also indicated the differentiability of images between the peritoneum and extra-peritoneal tissue layers. A success rate of 97.5% could be achieved with the guidance of the OCT images. OCT images translate the blind closed technique of peritoneal access into a visualized procedure, thus improving peritoneal access safety.

Fire safety study on high-flow nasal oxygen in shared-airway surgeries with diathermy and laser: simulation based on a physical model.

High-flow nasal oxygen (HFNO) has been used in "tubeless" shared-airway surgeries but whether HFNO increased the fire hazard is yet to be examined. We used a physical model for simulation to explore fire safety through a series of ignition trials. An HFNO device was attached to a 3D-printed nose with nostrils connected to a degutted raw chicken. The HFNO device was set at twenty combinations of different oxygen concentration and gas flow rate. An electrocautery and diode laser were applied separately to a fat cube in the cavity of the chicken. Ten 30 s trials of continuous energy source application were conducted. An additional trial of continuous energy application was conducted if no ignition was observed for all the ten trials. A total of eight short flashes were observed in one hundred electrocautery tests; however, no continuous fire was observed among them. There were thirty-six events of ignition in one hundred trials with laser, twelve of which turned into violent self-sustained fires. The factors found to be related to a significantly increased chance of ignition included laser application, lower gas flow, and higher FiO2. The native tissue and smoke can ignite and turn into violent self-sustained fires under HFNO and continuous laser strikes, even in the absence of combustible materials. The results suggest that airway surgeries must be performed safely with HFNO if only a short intermittent laser is used in low FiO2.

How early warning with the Oxygen Reserve Index (ORi™) can improve the detection of desaturation during induction of general anesthesia?

The Oxygen Reserve Index (ORi™) is a dimensionless parameter with a value between 0 and 1. It is related to the real-time oxygenation status in the moderate hyperoxic range. The purpose of this study is to investigate the added warning time provided by different ORi alarm triggers and the continuous trends of ORi, SpO2, and PaO2. We enrolled 25 patients who were scheduled for elective surgery under general anesthesia with planned arterial catheterization before induction. The participants received standardized preoxygenation, induction, and intubation. The patients remained apneic and ventilation was resumed when the SpO2 fell below 90%. The ORi and SpO2 were recorded every ten seconds and arterial blood was sampled every minute, from preoxygenation to resumed ventilation. Alarm triggers set to the ORi peak and the ORi 0.55 values provided 300 and 145 s of significant added warning time compared to SpO2 (p < 0.0001). The coefficient of determination was 0.56 between the ORi and the PaO2 ≤ 240 mmHg and showed a positive correlation. The ORi enables the clinicians to monitor the patients' oxygen status during induction of general anesthesia and can improve the detection of impending desaturation. However, further studies are needed to assess its clinical potential in the high hyperoxic range.The protocol was retrospectively registered at ClinicalTrials.gov on July 21, 2021 (NCT04976504).

Strong Early Phase Parasympathetic Inhibition Followed by Sympathetic Withdrawal During Propofol Induction: Temporal Response Assessed by Wavelet-Based Spectral Analysis and Photoplethysmography.

Background: Induction of anesthesia with propofol is associated with a disturbance in hemodynamics, in part due to its effects on parasympathetic and sympathetic tone. The impact of propofol on autonomic function is unclear. In this study, we investigated in detail the changes in the cardiac autonomic nervous system (ANS) and peripheral sympathetic outflow that occur during the induction of anesthesia. Methods: Electrocardiography and pulse photoplethysmography (PPG) signals were recorded and analyzed from 30 s before to 120 s after propofol induction. The spectrogram was derived by continuous wavelet transform with the power of instantaneous high-frequency (HFi) and low-frequency (LFi) bands extracted at 1-s intervals. The wavelet-based parameters were then divided into the following segments: (1) baseline (30 s before administration of propofol), (2) early phase (first minute after administration of propofol), and (3) late phase (second minute after administration of propofol) and compared with the same time intervals of the Fourier-based spectrum [high-frequency (HF) and low-frequency (LF) bands]. Time-dependent effects were explored using fractional polynomials and repeated-measures analysis of variance. Results: Administration of propofol resulted in reductions in HFi and LFi and increases in the LFi/HFi ratio and PPG amplitude, which had a significant non-linear relationship. Significant between-group differences were found in the HFi, LFi, and LFi/HFi ratio and Fourier-based HF and LF after dividing the segments into baseline and early/late phases. On post hoc analysis, changes in HFi, LFi, and the LFi/HFi ratio were significant starting from the early phase. The corresponding effect size (partial eta squared) was > 0.3, achieving power over 90%; however, significant decreases in HF and LF were observed only in the late phase. The PPG amplitude was increased significantly in both the early and late phases. Conclusion: Propofol induction results in significant immediate changes in ANS activity that include temporally relative elevation of cardiac sympathovagal balance and reduced sympathetic activity. Clinical Trial Registration: The study was approved by the Institutional Review Board of Taipei Veterans General Hospital (No. 2017-07-009CC) and is registered at ClinicalTrials.gov (https://clinicaltrials.gov/ct2/show/NCT03613961).

Intercostal Nerve Block Using an Innovative Intraneedle Ultrasound Transducer: A Proof-of-Concept study.

Intercostal nerve block is a widely used and effective approach to providing regional anesthesia in the thoracic region for pain relief. However, during ultrasound-guided intercostal nerve block, inaccurate identification of the anatomic structures or suboptimal positioning of the needle tip may result in complications and blockade failure. In this study, we designed an intraneedle ultrasound (INUS) system and validated its efficacy in identifying anatomic structures relevant to thoracic region anesthesia. The 20-MHz INUS transducer comprised a single lead magnesium niobate-lead titanate crystal, and gain was set to 20 dB. It fit into a regular 18G needle and emitted radiofrequency-mode ultrasound signals at 1 mm from the needle tip. One hundred intercostal punctures were performed in 10 piglets. Intercostal spaces were identified by surface ultrasound or palpation and located by inserting and advancing the INUS transducer needle until the appropriate anatomy was identified. Blockade success was defined by ideal saline and dye spreading and confirmed by dissection. The pleura had a distinctive ultrasound signal, and successful detection of the intercostal muscles, endothoracic fascia and double-layered parietal and visceral pleura was achieved in all 100 puncture attempts. INUS allows real-time identification of intercostal structures and facilitates successful intercostal nerve blocks.

Nonintubated versus intubated "one-stage" preoperative localization and thoracoscopic lung resection.

OBJECTIVE: Nonintubated anesthesia, electromagnetic navigation (EMN)-guided preoperative localization, and uniportal video-assisted thoracic surgery (VATS) are recent innovations in minimally invasive thoracic surgery. This study aimed to explore the feasibility of applying nonintubated anesthesia in a "one-stage" localization and resection workflow. METHODS: Patients who underwent EMN-guided preoperative percutaneous localization with indocyanine green (ICG) and uniportal VATS were included. Perioperative data were compared between patients receiving nonintubated anesthesia and those receiving general anesthesia with endotracheal intubation. RESULTS: Forty-six patients with a total of 50 nodules were included in the study. Overall, finger palpation could be avoided in 94% of the nodules, whereas fluorescent green signals with a clear border on the pleural surface were noted in 91.3% (21 of 23) of nodules in the nonintubated group and 88.9% (24 of 27) of nodules in the intubated group. Intraoperatively, the nonintubated group had a lower median pH (7.33 [interquartile range (IQR), 7.28-7.40] vs 7.41 [IQR, 7.38-7.44]; P = .003), higher median arterial CO2 (45.5 [IQR, 41.1-58.7] mm Hg vs 38.4 [IQR, 35.3-40.6] mm Hg; P < .001), and lower arterial oxygen (322 [IQR, 211-433] mm Hg vs 426 [IQR, 355-471] mm Hg; P = .005) levels compared with the intubated group. The nonintubated group also had a shorter median registration time (2.0 [IQR, 1.0-3.0] minutes vs 3.0 [IQR, 2.0-8.0] minutes; P = .008) and total time in the operating room (150 [IQR, 130-175] minutes vs 170 [IQR, 135-203] minutes; P = .035), whereas no between-group differences were seen in localization and operative time. The duration of chest drainage, postoperative complications, pathologic diagnosis, and margins were similar in the 2 groups. CONCLUSIONS: Nonintubated "one-stage" EMN-guided percutaneous ICG localization and uniportal VATS can be an option for selected patients undergoing treatment for small peripheral nodules.

Fiber-Needle Swept-Source Optical Coherence Tomography for the Real-Time Visualization of the Transversus Abdominis Plane Block Procedure in a Swine Model.

BACKGROUND: Fascia blocks (eg, the transversus abdominis plane [TAP] block) target the intermuscular fascia layers. Ultrasound techniques have allowed peripheral blocks to be performed with accuracy and safety, however, with limitations. Optical coherence tomography (OCT) is based on low-coherence interferometry. In this study, we examined the ability of OCT to identify the TAP. METHODS: A swept-source OCT probe was placed in a 17-gauge needle to obtain imaging. The needle was inserted within 2 different angle ranges (0°-30° and 30°-60°) on a slice of pork belly to assess imaging characteristics. A series of real-time OCT imaging of the muscle, fascia, and interfascial space was obtained. The tissue location of the needle tip was identified using near-infrared (NIR) imaging. In vivo OCT imaging was further done on 3 female 6-month-old native Chinese Landrance Duroc pigs. Real-time images of tissue layers were obtained with needle insertion. Ultrasound imaging of the OCT needle probe was also performed at the same time for needle trajectory guidance. After imaging, the OCT probe was removed, and 5 mL of normal saline was injected via the needle to confirm correct fascia plane identification. RESULTS: In and ex vivo studies showed clear visual distinction of muscle, fascia, and interfascial layer with OCT, with limitations. Independent validation of OCT criteria for the muscle/fascia differentiation by 20 OCT readers for the in vivo data demonstrated the sensitivity = 0.91, specificity = 0.90, and accuracy = 0.89. Although the angle of needle entry affected the depth of OCT penetration in the muscle, the attenuation coefficient values of the fascia and muscle tissue were statistically different (P < .001) and with high area under the receiver operating characteristics (ROC) curve (AUC) (AUC = 0.93 in 0°-30° and AUC = 1 in 30°-60°) for fascia identification. CONCLUSIONS: This study introduced a novel needle imaging probe method to identify the transversus abdominis fascia plane in real-time. Quantitative calculation of the attenuation coefficients can further aid objective identification by providing direct confirmation of the tip position, increasing the first-pass success rate, and decreasing the need for needle repositioning. Combining OCT and ultrasound may improve the accuracy of anesthetics placement.