Differences in perception of online anesthesiology between Thai medical students and teachers during the COVID-19 pandemic.

PURPOSE: Traditional anesthesiology learning was disrupted by the coronavirus disease 2019 pandemic and replaced by online learning. Students and teachers did not prepare well for this change. Determining the differences in perceptions can close the gap and develop more effective curricula. Our study aims to compare students' and teachers' perceptions of online anesthesiology learning. METHODS: We conducted a prospective descriptive study, a cross-sectional survey between July 2020 and January 2021 in the Anesthesiology Department, Faculty of Medicine, Khon Kaen University, Thailand. Our participants were fifth-year medical students and teachers participating in online anesthesiology. We compared the perception of the teaching process, support system, learning outcomes, satisfaction, and preference. Using an online structured questionnaire survey with a 4-point Likert scale to measure the degree of agreement with each item. We analyzed the difference between students' and teachers' perceptions by topic. RESULTS: We received responses from 174 students and 24 teachers. Students had a significantly higher proportion of positive perceptions than teachers on the teaching process (theoretical teaching, problem-based learning, feedback, and response system), on a support system (technological support, connectivity, and learning materials), on learning outcomes (clinical practice readiness, critical thinking, long-term memory, and enthusiasm), satisfaction score, and online learning preference (p<0.05). CONCLUSION: Differences in perception were high in many aspects of online anesthesiology learning. This perception gap was particularly evident in the teaching process, support system, and learning outcomes. And Thai students had more preference for online learning than teachers. Strategies to reduce the gap should focus on teachers' training and supporting online learning should be concerned.

Eficacia de la tromboprofilaxis con heparina de bajo peso molecular en pacientes críticos con COVID-19: estudio observacional, prospectivo y multicéntrico / Effectiveness of thromboprophylaxis with low molecular weight heparin in critically ill patients with COVID-19. An observational prospective, multicenter study

Introducción: Los pacientes COVID-19 presentan una coagulopatía caracterizada por una elevada incidencia de complicaciones tromboembólicas. Ante la controversia existente sobre el manejo de la tromboprofilaxis, se llevó a cabo un estudio con el objetivo de analizar el efecto de las diferentes dosis de heparina de bajo peso molecular (HBPM) utilizadas en los pacientes críticos con COVID-19. Material y métodos: Se evaluaron datos del Reg-COVID-19. Se compararon 2 grupos de pacientes según la dosis de HBPM administrada: profilaxis y tratamiento. El objetivo primario fue determinar si había relación de la dosis de HBPM con la mortalidad. Los objetivos secundarios incluyeron la incidencia de eventos trombóticos y hemorrágicos, la duración de la estancia en la UCI, la ventilación mecánica invasiva y los parámetros trombóticos e inflamatorios. Resultados: Se analizaron datos de 720 pacientes, 258 en el grupo de profilaxis y 462 en el de tratamiento. La proteína C reactiva, la ventilación mecánica invasiva y el tratamiento con tocilizumab o corticosteroides se relacionaron con la elección de la dosis de HBPM. La incidencia de complicaciones hemorrágicas (66/720, 9,2%) y trombóticas (69/720, 9,6%) fue similar en ambos grupos, al igual que el curso temporal de los eventos trombóticos, que ocurrieron antes que los hemorrágicos (9 [3-18] y 12 [6-19] días, respectivamente). La mortalidad fue menor en el grupo de profilaxis (25,2 frente al 35,1%), pero al aplicar un modelo de ponderación de probabilidad inversa, no se encontraron diferencias entre los grupos. Conclusión: No se encontraron efectos beneficiosos ni perjudiciales relacionados con la administración de dosis profilácticas o terapéuticas de HBPM en pacientes críticos COVID-19, con una tasa similar de complicaciones hemorrágicas o trombóticas. A partir de estos resultados, consideramos que son necesarios más estudios para determinar el protocolo óptimo de tromboprofilaxis en estos pacientes.(AU)

Introduction: COVID-19 induces coagulopathy associated with an increase of thromboembolic events. Due to the lack of agreement on recommendations for thromboprophylactic management, the aim of this study was to study the dosages of LMWH used in critically ill COVID-19 patients assessing the effect on their outcome. Metohds: We evaluated data of the Reg-COVID19. According to LMWH dose two groups were analyzed: prophylaxis and treatment. Primary outcome was the relationship of LMWH dosage with mortality. Secondary outcomes included the incidence of thrombotic and bleeding events, length of ICU stay, invasive mechanical ventilation, and thrombotic and inflammatory parameters. Results: Data of 720 patients were analyzed, 258 in the prophylaxis group and 462 in the treatment group. C Reactive Protein, invasive mechanical ventilation, tocilizumab and corticosteroid treatments were related with the choice of LMWH dose. Hemorrhagic events (66/720, 9.2%) and thrombotic complications (69/720, 9.6%) were similar in both groups (P=.819 and P=.265), as was the time course of the thrombotic events, earlier than hemorrhagic ones (9 [3-18] and 12 [6-19] days respectively). Mortality was lower in prophylaxis group (25.2% versus 35.1%), but once an inverse probability weighting model was applied, we found no effect of LMWH dose. Conclusion: We found no benefit or harm with the administration of therapeutic or prophylactic LMWH dose in COVID19 critically ill patients. With a similar rate of hemorrhagic or thrombotic events, the LMWH dose had no influence on mortality. More studies are needed to determine the optimal thromboprophylaxis protocol for critically ill patients.(AU)

La anestesia subaracnoidea no produce disfunción ventricular izquierda transitoria en pacientes mayores de 60 años sin enfermedad cardiovascular / Spinal anesthesia does not cause left ventricular dysfunction in patients older than 60 years without cardiovascular disease

Objetivos: Evaluar la función sistólica ventricular izquierda por ecocardiograma transtorácico en pacientes mayores de 60 años, sin enfermedad cardiovascular, bajo anestesia subaracnoidea instaurada. Pacientes y métodos: Estudio observacional prospectivo con un total de 54 pacientes mayores de 60 años sin enfermedad cardiovascular, a quienes, tras la instauración de una anestesia subaracnoidea con bupivacaína hiperbárica al 0,5% con bloqueo sensitivoT10 o mayor, se les midió la función sistólica ventricular izquierda a partir del movimiento sistólico del anillo mitral (mitral anular plane systolic excursion [MAPSE].) Además, se midió el índice de colapsabilidad de vena cava inferior (ICVCI), la integral velocidad tiempo del tracto de salida del ventrículo izquierdo (ITTSVI) y del gasto cardiaco (GC). Los valores a los 5min del bloqueo se compararon con los obtenidos previamente al mismo. Resultados: Se evidenció una disminución del 3,3% del MAPSE y una ligera disminución del IVTTSVI y GC, en ningún caso con significación estadística ni clínica. El 14,8% de los pacientes presentó presión arterial media (PAM) igual o inferior a 60mmHg. La comparación de los cambios ecocardiográficos entre estos pacientes y los que no presentaron hipotensión no fueron estadísticamente significativos ni clínicamente relevantes. Discusión: Se demuestra que la anestesia subaracnoidea con nivel anestésico T10 o superior en pacientes mayores de 60 años sin enfermedad cardiovascular, es una técnica segura ya que no altera de forma significativa parámetros ecocardiográficos de medición de la función sistólica ventricular izquierda.(AU)

Background: Elderly patients are undergoing surgery more frequently than ever. In this population, spinal anesthesia, which is known to cause sympathetic blockade associated with arterial vasodilation, is proposed as an excellent option. However, its effects on left ventricular systolic function have not been studied. Objectives: To evaluate left ventricular systolic function by transthoracic echocardiography in patients older than 60 years, without prior cardiovascular disease, under spinal anesthesia. Patients and methods: Prospective observational study with a total of 54 patients older than 60 years without prior cardiovascular disease, in whom, after the completion of subarachnoid anesthesia with hyperbaric 0.5% bupivacaine with sensory block equal to or greater than T10, left ventricular systolic function was measured using MAPSE. In addition, CI-IVC, LVOT-VTI and CO were measured. Values at 5 minutes after the blockade were compared with those obtained previously. Results: A 3.3% decrease in MAPSE and a slight decrease in LVOT-VTI and CO were found, with no statistical or clinical significance. The 14.8% of the patients presented MAP equal to or less than 60mmHg. Comparison of echocardiographic changes between hypotensive and non-hypotensive patients was not statistically significant or clinically relevant. Discussion: Our study shows that spinal anesthesia with anesthetic level T10 or higher in patients older than 60 years without cardiovascular disease is a safe technique since it does not significantly alter echocardiographic parameters measuring left ventricular systolic function.(AU)

Herniación gástrica por rotura de prótesis diafragmática en el postoperatorio de pleuroneumonectomía por mesotelioma: una complicación a tener en cuenta / Gastric herniation due to rupture of diaphragmatic prosthesis in the postoperative period of pleuropneumonectomy due to mesothelioma: A complication to consider

La neumonectomía extrapleural, habitualmente asociada a reconstrucción pericárdica y diafragmática con material protésico, es una de las técnicas quirúrgicas empleadas en el tratamiento del mesotelioma pleural maligno. La herniación de vísceras abdominales hacia el tórax a través del material protésico a nivel diafragmático es una complicación rara, pero potencialmente grave de estos procedimientos, que debe de ser diagnosticada rápidamente para su reparación urgente.Presentamos el caso de un paciente que presentó una herniación gástrica en el postoperatorio precoz de una neumonectomía izquierda por un mesotelioma pleural. Los hallazgos clínicos fueron leves, pero apoyados en las pruebas de imagen, confirmaron la hipótesis diagnóstica y facilitaron la solución del cuadro. Se revisan los posibles factores contribuyentes y se incide en la necesidad de un diagnóstico y tratamiento precoz para evitar la isquemia de las vísceras abdominales herniadas en la cavidad torácica, por el riesgo de necrosis y contaminación por material fecaloideo.(AU)

Extrapleural pneumonectomy, usually associated with pericardial and diaphragmatic reconstruction with prosthetic material, is one of the surgical techniques used in the treatment of malignant pleural mesothelioma. Herniation of the abdominal viscera towards the thorax through the prosthetic material at the diaphragmatic level is a rare but potentially serious complication of these procedures, which must be diagnosed quickly for urgent repair.We present the case of a patient who presented with gastric herniation in the early postoperative period of a left pneumonectomy due to pleural mesothelioma. The clinical findings were mild, but supported by imaging tests, they confirmed the diagnostic hypothesis and facilitated the solution of the condition. Possible contributing factors are reviewed and the need for early diagnosis and treatment is emphasized to avoid ischemia of herniated abdominal viscera in the thoracic cavity, due to the risk of necrosis and contamination by fecaloid material.(AU)

Neumoencéfalo, coma y convulsiones después de una cirugía de descompresión lumbar / Pneumocephalus, coma and seizures following lumbar decompression surgery

Describimos un caso de neumoencéfalo en una paciente con estenosis de canal medular por espondilolistesis degenerativa tras cirugía de descompresión lumbar. El caso comienza en el momento del despertar de la anestesia, en el que la paciente presenta bajo nivel de consciencia, sin respuesta de apertura ocular, ninguna respuesta verbal y la respuesta motora sOlo retira en respuesta al dolor (Glasgow 7), que precisa ingreso en la unidad de cuidados intensivos para ventilación mecánica. Posteriormente la paciente experimentó una crisis convulsiva tónico-clónica generalizada, por lo que se realizó una tomografía computarizada (TC) donde se observa un neumoencéfalo voluminoso con un efecto ocupante de espacio en los lóbulos frontal y parietal, los ventrículos laterales y la cisterna.Se inició terapia antiepiléptica (diazepam y levetiracetam) y vigilancia neurológica. A las 12h postoperatorias, la TC repetida demostró que el neumoencéfalo había mejorado persistiendo una cantidad mínima que Solo se limitaba al lóbulo frontal. La consciencia persistía severamente disminuida. El electroencefalograma mostró actividad epileptiforme continua y la adicción de fenitoína continua intravenosa al tratamiento antiepiléptico previo consigue mejorar gradualmente el nivel de consciencia y las respuestas motoras y verbales. A las pocas horas, la paciente fue extubada y no presentó déficits neurológicos posteriores. El neumoencéfalo debe considerarse en el diagnóstico diferencial cuando se evalúa a un paciente con un estado mental alterado después de una cirugía lumbar.(AU)

We describe a patient with pneumocephalus following lumbar decompression surgery who presented altered mental status at time to awake of anesthesia and the patient was admitted in intesive care unit in mechanical ventilation. The patient has not eye-opening response, no verbal response and motor response only withdraw in response to pain (7 points on Glasgow coma scale). Then, the patient experienced a generalized tonic-clonic seizure. Immediate cranial computed tomography (CT) images were performed. Cerebral pneumocephalus was present in CT, imaging revealed a voluminous pneumocephalus responsible for a significantspace-occupying effect on the frontal and parietal lobes, lateral ventricles and quadrigeminal plate cistern.Anti-epileptic therapy (diazepam and levetiracetam) and neurological monitoring were initiated. At 12 postoperative hours repeat CT scanning showed pneumocephalus were completely improved to minimal quantity and only limited to frontal lobe. The consciousness is impaired, and a generalized tonic-clonic seizure was present. Electroencephalogram showed continuous epileptiform activity and phenytoin IV was administered in continuous infusión. Four hours later the level of consciousness gradually improved, and the patient was right in eye opening, verbal and motor responses. A few hours later the patient was extubated, and no neurological deficits were present. Pneumocephalus should be considered in the differential diagnosis when evaluating a patient with altered mental status following lumbar surgery.(AU)

Hemorragia masiva tras fístula arterio-esofágica por una arteria subclavia aberrante desconocida / Massive hemorrhage after arterioesophageal fistula from an unknown aberrant subclavian artery

La arteria subclavia derecha aberrante tiene una incidencia de un 0,5-1% en la población, con una localización generalmente retroesofágica. Puede llevar a la formación de una fístula arterio-esofágica en pacientes con factores de riesgo predisponentes por dispositivos colocados en posición esofágica o traqueal, al ser particularmente susceptible a la compresión extrínseca y a la necrosis por presión.Presentamos el caso de un paciente con una fístula traqueo-esofágica posquirúrgica, que desarrolló un sangrado masivo por una fístula arterio-esofágica secundaria a una arteria subclavia derecha aberrante desconocida. Para el manejo hemostático se realizaron maniobras alternativas, como la colocación de una sonda urinaria tipo Foley en el punto de sangrado y la posterior colocación de un balón de Sengstaken-Blakemore en posición craneal.Dada la gravedad del cuadro y el posible retraso diagnóstico, parece adecuado considerar la realización de un angio-TC preoperatorio en pacientes con factores de riesgo sometidos a estos procedimientos.(AU)

The aberrant right subclavian artery has an incidence of 0.5-1% in the population, generally with retroesophageal location. It can lead to the formation of an arterio-esophageal fistula in patients with predisposing risk factors due to devices placed in esophageal or tracheal position, as it is particularly susceptible to extrinsic compression and pressure necrosis.We present the case of a patient with a postsurgical tracheoesophageal fistula, who developed massive bleeding due to an arterioesophageal fistula secondary to an unknown aberrant right subclavian artery. For hemostatic management, alternative maneuvers were performed, such as the placement of a Foley-type urinary catheter at the point of bleeding and the subsequent placement of a Sengstaken-Blakemore balloon in cranial position.Given the severity of the condition and the possible diagnostic delay, it seems appropriate to consider performing a preoperative CT angiography in patients with risk factors who undergo these procedures.(AU)

Coagulopathy and Emergent Reversal of Anticoagulation.

More patients than ever are presenting for urgent or emergent procedures while therapeutically anticoagulated for various medical indications. Medications including warfarin, antiplatelet agents such as clopidogrel, direct oral anticoagulants such as apixaban, and even heparin or heparinoids may be present. Each of these medication classes presents its own challenges when coagulopathy needs to be quickly corrected. This review article presents evidence-based discussions of monitoring and reversal of these medication-induced coagulopathies. In addition, there will be a brief discussion of other potential coagulopathies that may be encountered in providing acute care anesthesia.

Management of severe peri-operative bleeding: Guidelines from the European Society of Anaesthesiology and Intensive Care: Second update 2022.

BACKGROUND: Management of peri-operative bleeding is complex and involves multiple assessment tools and strategies to ensure optimal patient care with the goal of reducing morbidity and mortality. These updated guidelines from the European Society of Anaesthesiology and Intensive Care (ESAIC) aim to provide an evidence-based set of recommendations for healthcare professionals to help ensure improved clinical management. DESIGN: A systematic literature search from 2015 to 2021 of several electronic databases was performed without language restrictions. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used to assess the methodological quality of the included studies and to formulate recommendations. A Delphi methodology was used to prepare a clinical practice guideline. RESULTS: These searches identified 137 999 articles. All articles were assessed, and the existing 2017 guidelines were revised to incorporate new evidence. Sixteen recommendations derived from the systematic literature search, and four clinical guidances retained from previous ESAIC guidelines were formulated. Using the Delphi process on 253 sentences of guidance, strong consensus (>90% agreement) was achieved in 97% and consensus (75 to 90% agreement) in 3%. DISCUSSION: Peri-operative bleeding management encompasses the patient's journey from the pre-operative state through the postoperative period. Along this journey, many features of the patient's pre-operative coagulation status, underlying comorbidities, general health and the procedures that they are undergoing need to be taken into account. Due to the many important aspects in peri-operative nontrauma bleeding management, guidance as to how best approach and treat each individual patient are key. Understanding which therapeutic approaches are most valuable at each timepoint can only enhance patient care, ensuring the best outcomes by reducing blood loss and, therefore, overall morbidity and mortality. CONCLUSION: All healthcare professionals involved in the management of patients at risk for surgical bleeding should be aware of the current therapeutic options and approaches that are available to them. These guidelines aim to provide specific guidance for bleeding management in a variety of clinical situations.

Intraoperative pharmacologic opioid minimisation strategies and patient-centred outcomes after surgery: a scoping review protocol.

INTRODUCTION: For close to a century opioid administration has been a standard of care to complement anaesthesia during surgery. Considering the worldwide opioid epidemic, this practice is now being challenged and there is a growing use of systemic pharmacological opioid minimising strategies. Our aim is to conduct a scoping review that will examine clinical trials that have evaluated the impact of intraoperative opioid minimisation strategies on patient-centred outcomes and identify promising strategies. METHODS AND ANALYSIS: Our scoping review will follow the framework developed by Arksey and O'Malley. We will search MEDLINE, Embase, CENTRAL, Web of Science and CINAHL from their inception approximately in March 2023. We will include randomised controlled trials, assessing the impact of systemic intraoperative pharmacologic opioid minimisation strategies on patient-centred outcomes. We define an opioid minimisation strategy as any non-opioid drug with antinociceptive properties administered during the intraoperative period. Patient-centred outcomes will be defined and classified based on the consensus definitions established by the Standardised Endpoints in Perioperative Medicine initiative (StEP-COMPAC group) and informed by knowledge users and patient partners. We will use a coproduction approach involving interested parties. Our multidisciplinary team includes knowledge users, patient partners, methodologists and knowledge user organisations. Knowledge users will provide input on methods, outcomes, clinical significance of findings, implementation and feasibility. Patient partners will participate in assessing the relevance of our design, methods and outcomes and help to facilitate evidence translation. We will provide a thorough description of available clinical trials, compare their reported patient-centred outcome measures with established recommendations and identify promising strategies. ETHICS AND DISSEMINATION: Ethics approval is not required for the review. Our scoping review will inform future research including clinical trials and systematic reviews through identification of important intraoperative interventions. Results will be disseminated through a peer-reviewed publication, presentation at conferences and through our network of knowledge user collaborators. REGISTRATION: Open Science Foundation (currently embargoed).

The efficacy of nalmefene on anesthetic recovery of patients: a study protocol for a multicenter randomized controlled trial.

INTRODUCTION: So far, the recovery quality after general anesthesia is still unsatisfied. Nalmefene is a drug to treat opioid overdose and reverse opioid actions. We aim to investigate the efficacy of nalmefene on optimizing the recovery quality of patients after general anesthesia. METHODS: It is a prospective, placebo-controlled, two-arm parallel groups, multicentre, double-blind, randomized (PPPMDR) clinical trial. The participants (n = 520) will be randomly assigned into two groups. Each patient will receive either: a single dose of nalmefene 0.25 µg/kg in the intervention group, or the same volume of 0.9% NaCl solution in the control group at the end of the surgery. The primary outcome will be the time interval between the end of anaesthesia and recovery endpoints achieved (Aldrete recovery score ≥ 9) in post-anesthesia care unit (PACU). The other variables are the time interval from the end of operation to extubation; Richmond Agitation Sedation Scale (RASS) score at extubation; the time at Montreal Cognitive Assessment Scale (MoCA) orientation score ≥ 5; visual analog scale (VAS) score and adverse effects including postoperative nausea and vomiting (PONV), and pruritus in PACU and 24 h postoperatively. ANALYSIS: This trial aims to study whether small dose of nalmefene can shorten the time from the end of surgery to Aldrete score ≥ 9 and improve opioid-induced side effects.This trial focuses on providing the reliable clinical evidence for satisfactory quality of recovery. ETHICS AND DISSEMINATION: This clinical trial has been approved and supported by the ethics committee of the Renji Hospital, Shanghai Jiaotong University, School of Medicine (KY2020-150); Shanghai Tongren Hospital (2021-030-01);The First Affiliated Hospital of Guangxi Medical University (2021-032); and The First Affiliated Hospital of Zhengzhou University(2021-KY-0495-003). Analysis of the study results will be submitted to a peer-reviewed journal for publication. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04713358, Registered on September 23, 2021.

When policy meets reality: the new 18-hour on-call shift policy and the Israeli anesthesia workforce crisis.

BACKGROUND: The Israeli physician workforce faces multiple challenges. These include planned policies reducing physician on-call from 26 to 18 h and, from 2026, allowing only graduates of Ministry of Health approved foreign medical schools to take the Israeli licensing examination and an ongoing physician shortage (2019: Israel had 3.19 physicians/1000 persons vs. OECD average of 3.49 physicians/1000 persons). This study examines the potential impact of these planned policies on the Israeli anesthesiology workforce. METHODS: Surveys conducted among 34 public and private Israeli hospital anesthesiology department chairs collected data on their department's number of weekday on-call anesthesiologists and current shortage of anesthesiologists. A subsequent survey collected data on each anesthesiologist in the workforce, including the country where they studied medicine. RESULTS: Each weekday night there were 114 on-call anesthesiologists; 72 residents and 42 attendings. Using productive work coefficients, this translates to 104 resident and 51 attending anesthesiologists. Furthermore, 21 departments had existing anesthesia workforce shortages totaling 110 anesthesiologists. There were 873 anesthesiologists from non-OECD countries whose medical schools are not accredited by the World Federation for Medical Education, of whom 332 were residents (61.9% of residents). Only 20.1% of anesthesiology residents were Israeli medical school graduates. CONCLUSIONS: Descriptive survey data assessed the immediate and long-term consequences for the healthcare system and anesthesiology workforce of two new Health Ministry policies. Implementing the 18-h policy will immediately remove from the daytime workforce 155 anesthesiologists and who will be unavailable to staff elective surgery operating rooms. This will compound the current national shortage of 110 anesthesiologists. It is unclear how to replace this shortfall since there are no surplus Israeli physicians and very few Israeli graduates choose anesthesiology as a specialty. This situation will be exacerbated after 2026 when graduates of certain foreign medical schools will be unable to enter the medical workforce, further reducing the pool of potential anesthesiology residents. Both policies were promulgated without adequate operational and budgetary planning or fiscal or workforce resources; implementation of the 18-h on-call policy has already been postponed. Therefore, new or updated policies must be accompanied by specific operational plans, budgetary allocations and funds for additional workforce.

Necessity and Importance of Developing AI in Anesthesia from the Perspective of Clinical Safety and Information Security.

The rapid development of artificial intelligence (AI) technology is due to the significant progress in big data, databases, algorithms, and computing power, and medical research is a vital application direction of AI. The integrated development of AI and medicine has improved medical technology, and the efficiency of medical services and equipment has enabled doctors to better serve patients. The tasks and characteristics of the anesthesia discipline also make AI necessary for its development, and AI has also been initially applied in different fields of anesthesia. Our review aims to clarify the current situation and challenges of AI application in anesthesiology to provide clinical references and guide the future development of AI in anesthesiology. This review summarizes progress in the application of AI in perioperative risk assessment and prediction, deep monitoring and regulation of anesthesia, essential anesthesia skills operation, automatic drug administration systems, and teaching and training in anesthesia. Also discussed herein are the accompanying risks and challenges of applying AI in anesthesia: patient privacy and information security, data sources, and ethical issues, lack of capital and talent, and the "black box" phenomenon.