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IMPORTANCE: Cataract surgery in the US is routinely performed with anesthesia care, whereas anesthesia care for other elective, low-risk, outpatient procedures is applied more selectively. OBJECTIVE: To identify predictors of anesthesia care in Medicare beneficiaries undergoing cataract surgery and evaluate anesthesia care for cataract surgery compared with other elective, low-risk, outpatient procedures. DESIGN, SETTING, AND PARTICIPANTS: This population-based, retrospective observational cohort study included Medicare beneficiaries 66 years or older who underwent cataract surgery in 2017. The data were analyzed from August 2020 through May 2021. INTERVENTIONS (FOR CLINICAL TRIALS) OR EXPOSURES (FOR OBSERVATIONAL STUDIES): Anesthesia care during elective, low-risk, outpatient procedures. MAIN OUTCOMES AND MEASURES: Prevalence of anesthesia care during cataract surgery compared with other low-risk procedures; association of anesthesia care with patient, clinician, and health system characteristics; and proportion of patients experiencing a systemic complication within 7 days of cataract surgery compared with patients undergoing other low-risk procedures. RESULTS: Among 36 652 cataract surgery patients, the mean (SD) age was 74.7 (6.1) years; 21 690 (59.2%) were female; 2200 (6.6%) were Black and 32 049 (87.4%) were White. Anesthesia care was more common among patients undergoing cataract surgery compared with patients undergoing other low-risk procedures (89.8% vs range of <1% to 70.2%). Neither the patient’s age (adjusted odds ratio, 1.01; 95% CI, 1.00-1.02; P = .01) nor Charlson Comorbidity Index (CCI) score (CCI of ≥3: adjusted odds ratio, 1.06; 95% CI, 0.95-1.18; P = .28; reference, CCI score of 0-1) was strongly associated with anesthesia care for cataract surgery, but a model comprising a single variable identifying the ophthalmologist predicted anesthesia care with a C statistic of 0.96. Approximately 6.0% of ophthalmologists never used anesthesia care, 76.6% always used anesthesia care, and 17.4% used it for only a subset of patients. Fewer cataract surgery patients experienced systemic complications within 7 days (2833 [7.7%]), even when limited to patients of ophthalmologists who never used anesthesia care (108 [7.4%]), than patients undergoing other low-risk procedures (range, 13.2%-52.2%). CONCLUSIONS AND RELEVANCE: The results of this cohort study suggest that systemic complications occurred less frequently after cataract surgery compared with other elective, low-risk, outpatient procedures during which anesthesia care was less commonly used. Anesthesia care was not associated with patient characteristics, such as older age or worse health status, but with the ophthalmologists’ usual approach to cataract surgery sedation. The study findings suggest an opportunity to use anesthesia care more selectively in patients undergoing cataract surgery.

Capnometry, the measurement of respiratory carbon dioxide, is regarded as a highly recommended safety technology in intubated and nonintubated sedated and/or anesthetized patients. Its utility includes confirmation of initial and ongoing placement of an airway device as well as in detecting gas exchange, bronchospasm, airway obstruction, reduced cardiac output, and metabolic changes. The utility applies prehospital and throughout all phases of inhospital care. Unfortunately, capnometry devices are not readily available in many countries, especially those that are resource-limited. Constraining factors include cost, durability of devices, availability of consumables, lack of dependable power supply, difficulty with cleaning, and maintenance. There is, thus, an urgent need for all stakeholders to come together to develop, market, and distribute appropriate devices that address costs and other requirements. To foster this process, the World Federation of Societies of Anaesthesiologists (WFSA) has developed the “WFSA—Minimum Capnometer Specifications 2021.” The intent of the specifications is to set the minimum that would be acceptable from industry in their attempts to reduce costs while meeting other needs in resource-constrained regions. The document also includes very desirable and preferred options. The intent is to stimulate interest and engagement among industry, clinical providers, professional associations, and ministries of health to address this important patient safety need. The WFSA—Minimum Capnometer Specifications 2021 is based on the International Organization for Standardization (ISO) capnometer specifications. While industry is familiar with such specifications and their presentation format, most clinicians are not; therefore, this article serves to more clearly explain the requirements. In addition, the specifications as described can be used as a purchasing guide by clinicians.

Purpose: Perioperative stroke is associated with significant morbidity and mortality yet patients may not be aware of their risk or receive appropriate counselling. Our objectives were to 1) compare patient’s perceived vscalculated risk of stroke; 2) determine level of worry; and 3) assess prior discussion about perioperative stroke risk amongst elective patients undergoing non-cardiac, non-neurologic surgery. Methods: Over a consecutive four-week period, surveys were distributed at two pre-anesthetic clinics to adult patients scheduled for non-cardiac, non-neurologic surgery. The survey included questions about demographics, perioperative stroke risk factors, patient perception of their quantitative and qualitative stroke risk, level of worry about stroke, and risk discussions. We identified independent predictors of risk underestimation amongst medium- and high-risk patients. Results: Six hundred patients completed the survey (response rate 78%). Of these, 479, 104, and 15 patients were classified as low-, medium-, and high-risk, respectively (with two patients missing this data point). Most medium- (86%) and high-risk (80%) patients did not identify their elevated risk. Amongst medium- and high-risk patients, independent predictors of risk underestimation were lower education and absence of kidney disease. Medium- and high-risk patients were more worried than low-risk patients about perioperative stroke (median [interquartile range] visual analogue scale score 2 [0.5–4] vs1 [0–2], P= 0.001). Fewer than half of patients had discussed perioperative stroke previously (40%, 23%, and 12% of high-, medium-, and low-risk patients, respectively). Conclusions: Patients at higher risk of stroke frequently underestimate their risk of perioperative stroke. The majority of patients had not discussed perioperative stroke prior to anesthetic consultation.

The α2-adrenergic receptor agonist dexmedetomidine has sedative, anxiolytic, analgesic, and sympatholytic effects. The potential advantages of neuroprotection, minimal impact on neuronal function, stable hemodynamics, opioid and anesthesia sparing effects, and minimal respiratory depression during awake procedures render it an effective anesthetic adjuvant in various neurosurgical settings. However, both the benefits and drawbacks of the use dexmedetomidine in neuroanesthesia should be considered. This narrative review will summarize the applications of dexmedetomidine in various neurosurgical settings, highlighting evidence regarding both its common and controversial uses.

Supplemental Digital Content is available in the text.Perioperative stroke is associated with considerable morbidity and mortality. Stroke recognition and diagnosis are challenging perioperatively, and surgical patients receive therapeutic interventions less frequently compared with stroke patients in the outpatient setting. These updated guidelines from the Society for Neuroscience in Anesthesiology and Critical Care provide evidence-based recommendations regarding perioperative care of patients at high risk for stroke. Recommended areas for future investigation are also proposed.

In the Sustainable Development Goals era, there is a new awareness of the need for an integrated approach to healthcare interventions and a strong commitment to Universal Health Coverage. To achieve the goal of strengthening entire health systems, surgery, as a crosscutting treatment modality, is indispensable. For any health system strengthening exercise, baseline data and longitudinal monitoring of progress are necessary. With improved data capabilities, there are unparalleled possibilities to map out and understand systems, integrating data from many sources and sectors. Nevertheless, there is also a need to prioritize among indicators to avoid information overload and data collection fatigue. There is a similar need to define indicators and collection methodology to create standardized and comparable data. Finally, there is a need to establish data pathways to ensure clear responsibilities amongst national and international institutions and integrate surgical metrics into existing mechanisms for sustainable data collection. This is a call to collect, aggregate, and analyze global anesthesia and surgery data, with an account of existing data sources and a proposed way forward.

IMPORTANCE: Routine preoperative medical testing is not recommended for patients undergoing low-risk surgery, but testing is common before surgery. A 30-day preoperative testing window is conventionally used for study purposes; however, the extent of routine testing that occurs prior to that point is unknown. OBJECTIVE: To improve on existing cost estimates by identifying all routine preoperative testing that takes place after the decision is made to perform cataract surgery. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study assessed preoperative care in a 50% sample of Medicare beneficiaries older than 66 years who underwent ambulatory cataract surgery in 2011. Data analysis was completed from March 2016 to October 2017. MAIN OUTCOMES AND MEASURES: Using ocular biometry as a procedure-specific indicator to mark the start of the routine preoperative testing window, we measured testing rates in the interval between ocular biometry and cataract surgery and compared this with testing rates in the 6 months preceding biometry. We estimated the total cost of testing that occurred between biometry and cataract surgery. RESULTS: A total of 440 857 patients underwent cataract surgery. A total of 423 710 (96.1%) had an ocular biometry claim before index surgery, of whom 264 514 (60.0%) were female; the mean (SD) age of the cohort was 76.1 (6.2) years. A total of 111 998 (25.4%) underwent surgery more than 30 days after biometry. Among patients with a biometry claim, the mean number of tests/patient/month increased from 1.1 in the baseline period to 1.7 in the interval between biometry and cataract surgery. Although preoperative testing peaked in all patients in the 30 days preceding surgery (1.8 tests/patient/month), the subset of patients with no overlap between postbiometry and presurgery periods experienced increased testing rates to 1.8 tests per patient per month in the 30 days after biometry, regardless of the elapsed time between biometry and surgery. The total estimated cost of routine preoperative testing in the full cohort was $22.7 million; we estimate that routine preoperative testing costs Medicare up to $45.4 million annually. CONCLUSIONS AND RELEVANCE: In this study of Medicare beneficiaries, routine preoperative medical testing occurs more often and is costlier than has been reported previously. Extra costs are attributable to testing that occurs prior to the 30-day window preceding surgery. As a cost-cutting measure, routine preoperative medical testing should be avoided in patients with cataracts throughout the interval between ocular biometry and cataract surgery.

Awake craniotomy for brain tumor resection is becoming a standard of care for lesions residing within or in close proximity to regions presumed to have language or sensorimotor function. Evidence shows an improved outcome including greater extent of resection, fewer late neurological deficits, shorter hospital stay, and longer survival after awake brain tumor resection compared with surgery under general anesthesia. The surgeon’s ability to maximize tumor resection within the constraint of preserving neurological function by intraoperative stimulation mapping in an awake patient is credited for this advantageous result. It is possible that the care provided by anesthesiologists, especially the avoidance of certain components of general endotracheal anesthesia, may also be important in the outcome of awake brain tumor resection. We present our interpretation of the evidence that we believe substantiates this proposition. However, due to the lack of direct evidence based on randomized-controlled trials and the heterogeneity of anesthetic techniques used for awake craniotomy, our perspective is largely speculative and hypothesis generating that needs to be validated or refuted by future quality research.

Although most cerebral aneurysms are asymptomatic and discovered incidentally, their rupture often results in significant morbidity and mortality. The anesthesiologist may become involved in surgical clipping of aneurysms either before aneurysm rupture or after subarachnoid hemorrhage. After subarachnoid hemorrhage, a multisystemic preoperative evaluation is mandatory because both neurological complications (elevated intracranial pressure, rebleeding, hydrocephalus, vasospasm) and non-neurological complications (respiratory insufficiency, cardiac dysfunction, electrolyte abnormalities, endocrine disturbances) might influence anesthetic management. Besides being prepared for potential sudden profuse bleeding, the anesthesiologist caring for craniotomy for aneurysm clipping should follow four main principles. First, acute increase in the aneurysm transmural gradient (mean arterial pressure minus intracranial pressure) should be avoided to prevent rupture or rebleeding. Second, the cerebral perfusion pressure should be maintained with euvolemia and vasopressors to avoid brain ischemia caused either by brain retractors or temporary clipping of the feeding vessel. Third, surgical exposure should be optimized by providing brain relaxation with normal cerebral oxygenation, normal ventilation or transient hyperventilation, appropriate anesthetic choice, mannitol and perhaps lasix, and occasionally cerebrospinal fluid drainage. Fourth, early emergence is favored to allow recognition of potentially reversible complications. By being vigilant and achieving these goals, the anesthesiologist will contribute to optimal patient outcomes. The following article provides information to guide the anesthesiologist in optimal management of surgical clipping of aneurysms.

La oximetría cerebral basada en la espectroscopia cercana al infrarrojo puede medir de manera no invasiva la saturación de oxígeno de la hemoglobina en la sangre mixta arterial, venosa y capilar en el cerebro. A fin de determinar si este monitor es deseable en la clínica, es preciso responder 3 preguntas, en su orden. La primera es si la oximetría cerebral monitorea un aspecto importante de la fisiología. La segunda es si se puede optimizar la fisiología con base en este monitor. La tercera es si se puede mejorar el desenlace mediante una intervención clínica basada en la oximetría cerebral. En esta revisión presentamos nuestras respuestas a estas 3 preguntas.

Cerebral oximetry based on near-infrared spectroscopy can non-invasively measure hemoglobin oxygen saturation in mixed arterial, venous and capillary blood in the brain. In order to determine if this is a clinically desirable monitor, we need to answer three questions in order. The first question is if cerebral oximetry monitors an important aspect of physiology. The second question is if the physiology can be optimized based on this monitor. The third question is if the outcome can be improved based on cerebral oximetry-guided clinical care. In this review, we share our answers to these three questions.

A pesar de que la mayoría de los aneurismas cerebrales son asintomáticos y se describen incidentalmente, su ruptura suele resultar en una morbimortalidad significativa Por lo tanto, el anestesiólogo pudiera intervenir realizando un clipaje quirúrgico del aneurisma, bien sea de manera electiva o posterior a una hemorragia subaracnoidea. Luego de una hemorragia subaracnoidea es indispensable hacer una evaluación preoperatoria sistémica porque el manejo anestésico puede verse afectado tanto por las complicaciones neurológicas (presión intracraneal elevada, repetición de la hemorragia, hidrocefalia, vasoespasmo) y complicaciones no neurológicas (insuficiencia respiratoria, disfunción cardíaca, anomalías electrolíticas, alteraciones endocrinas). Además de estar preparado para una hemorragia profusa súbita, el anestesiólogo a cargo de una craneotomía para clipaje de un aneurisma debe adherirse a 4 principios fundamentales. Primero, debe evitarse el incremento agudo en el gradiente transmural del aneurisma (presión arterial media menos la presión intracraneal) para impedir una ruptura o recurrencia de hemorragia. Segundo, la presión de perfusión cerebral debe mantenerse con euvolemia y vasopresores para evitar isquemia cerebral, bien sea con separadores cerebrales o clipaje temporal del vaso nutriente. Tercero, debe optimizarse la exposición quirúrgica con relajación cerebral mediante oxigenación y ventilación cerebral normal, selección apropiada del anestésico, manitol y tal vez lasix, drenaje de líquido cefalorraquídeo o hiperventilación transitoria. Cuarto, se recomienda el despertar temprano de la anestesia para reconocer precozmente las complicaciones potencialmente reversibles. Siendo vigilante y logrando estas metas, el anestesiólogo contribuirá al logro de desenlaces óptimos para el paciente.

This document is supported by the American Society of Anesthesiologists.

The review highlights recent data regarding the safety and efficacy of endovascular treatment of cerebrovascular disease and concerns in anesthesia management.

Author: Lucas G.H.W. Citation: Can Anaesth Soc J 1960; 7: 237-56. Purpose: To review the history of the early development of cyclopropane Principal findings: Cyclopropane was initially investigated because it was thought to be the toxic element in ethylene. Instead, it turned out to be an excellent anesthetic with very rapid onset and recovery while maintaining stable hemodynamics. Its use was ultimately limited because it was highly explosive. Development required collaboration among laboratory scientists and clinicians in Toronto, Canada, clinicians in Madison, USA, and industry in both countries. Conclusions: The phenomenal success of cyclopropane in over 40 years of clinical use resulted from a lucky, but incorrect, hypothesis that it was a toxic contaminant.

Cerebrovascular disease is a common cause of death and disability worldwide. The current literature supports an association between blood pressure (BP) and patient outcome during acute stroke. This review will provide an overview of the evidence to guide BP management during acute stroke.

This article will provide a review of mentorship in academic medicine. The review will include definitions and an overview of the evidence supporting the benefits, barriers, and structure of mentorship programmes in academic medicine and anesthesia. Finally, we will identify areas of further research.

The purpose of the review is to describe what is currently known about the mechanisms, incidence and risk factors for acute and chronic postcraniotomy pain. The review will also summarize the evidence supporting the prevention and management of acute and chronic postcraniotomy pain.

Electrocardiographic abnormalities are common after subarachnoid hemorrhage, but their significance remains uncertain. The aim of this study was to determine whether any specific electrocardiographic abnormalities are independently associated with adverse neurological outcomes.

Purpose: To compare the recovery profiles, efficacy and safety of remifentanil and morphine for transitional analgesia with fentanyl in patients undergoing elective craniotomy for supratentorial mass lesions. Methods: Ninety-one patients were enrolled in this prospective, randomized, multicentre study. Anesthesia was induced with thiopental and remifentanil (1.0 μg · kg−1bolus and a 1 μg · kg−1· min−1infusion) or fentanyl (1 μg · kg−1bolus and a 1.0 μg · kg−1· min−1infusion). The opioid infusion continued until the level of anesthesia was deemed appropriate for intubation. Anesthesia was maintained with N2O/O2, isoflurane 0.5 MAC and remifentanil 0.2 μg · kg−1· mirr−1or fentanyl 0.04 μg · kg−1· min−1. At bone flap replacement, either morphine 0.08 mg · kg−1(remifentanil group) or saline (fentanyl group) was given. Results: Systolic blood pressure was greater in those receiving fentanyl during induction (145.6 ± 17.5 mmHgvs128.8 ± 18.3 mmHg;P= 0.006) and intubation (126.9 ± 17.1vs110.9 ± 16.5 mmHg;P< 0.001). Median time to tracheal extubation was similar but less variable in the remifentanil group (remifentanil = 8 min: range = 2–44 min; fentanyl = 8 min: range = 1–732 min). The fentanyl patients required a longer time to achieve the first normal neurological score (fentanyl = 38.0 min; remifentanil = 26.0 min;P= 0.035). Both the anesthesiologists and the recovery room nurses rated remifentanil better with respect to level of consciousness. Analgesics were required earlier in patients receiving remifentanil; median time 0.5vs1.08 hr,P< 0.001. Conclusions: Remifentanil is a suitable alternative to fentanyl in supratentorial craniotomy. Time to preoperative neurological recovery is faster and morphine provides some transitional analgesia without compromising the quality of recovery.

The goal of neuroprotection during carotid endarterectomy is a reduction in the frequency and severity of perioperative stroke. This includes cerebral ischemic events secondary to hypoperfusion during cross clamping, emboli, or both. However, rational use of protective techniques requires that patients at risk first be identified. This process begins with a thorough preoperative assessment, including neurological status and angiographic findings. lntraoperative monitoring is the next step in the identification. This can include the awake patient, electroencephalogram, transcranial Doppler, stump pressure or combinations of these. Unfortunately, evidence is lacking to demonstrate that any of these modalities is superior to another or to no monitoring at all. Finally, when a patient is at risk, a protective technique needs to be chosen. The use of surgical shunt placement has received mixed acceptance from surgeons performing these procedures. Barbiturate coma and anticoagulation may offer benefit but come with inherent risks as well. Maintenance of a high mean arterial pressure with vasopressors and fluids may also help improve collateral flow.

Oxygen-centered free radicals cause brain injury associated with trauma and stroke. These reactive oxygen species may be detoxified by endogenous antioxidants, but cell death occurs after antioxidants become depleted. General anesthetics penetrate into brain parenchyma, where they may abrogate oxidative injury to neurons by several mechanisms that prevent the initiation of free radical chain reactions or terminate the propagation of highly reactive radicals. First, general anesthetics may inhibit free radical generation because these drugs slow cerebral utilization of oxygen and glucose, inhibit oxidative metabolism in neutrophils, and prevent redox changes in hemoglobin. Second, antioxidant anesthetics, such as thiopental and propofol, directly scavenge reactive oxygen species and inhibit lipid peroxidation. Finally, anesthetics may prevent the elevation of extracellular glutamate concentration and inhibit the activation of excitatory glutamatergic receptors that augment oxidative stress after ischemia.

The use of remifentanil for sedation during awake epilepsy surgery has been described in a case report. However, little information is available regarding the effect of remifentanil on the quality of intraoperative electrocorticography (ECoG). This study was designed to investigate the effect of sedative doses of remifentanil on ECoG interictal spike activity among patients undergoing awake anterior temporal lobectomy for refractory epilepsy. Ten adult patients were studied prospectively. After baseline EcoG recordings were obtained, remifentanil was administered as a continuous infusion at 0.1 g/kg/min and the ECoG recorded continuously for 15 minutes. Recordings obtained before and during the administration of remifentanil were compared with respect to spike frequency and location. A trend toward a small decrease in spike frequency was observed as patients became increasingly somnolescent and background ECoG activity slowed. The difference was not statistically significant. Blood pressure and heart rate were not adversely affected by the administration of remifentanil. Respiratory rates decreased in all patients (mean decrease, 8 breaths/min) and one patient transiently developed a respiratory rate of 4 breaths per minute that elicited a decrease in the rate of remifentanil administration. Remifentanil administered at sedation doses does not adversely affect intraoperatively recorded interictal spike activity. Further investigation of the use of this drug during awake epilepsy surgery is warranted.

Using a rabbit model of intracranial hypertension, we studied the effects of infusion of phenylephrine on intracranial pressure (ICP) and cerebral perfusion pressure (CPP). Seven New Zealand white rabbits were anesthetized with isoflurane and normocapnia was maintained. An extradural balloon was used to raise ICP to 25 ± 1 mm Hg. Infusion of phenylephrine increased mean arterial blood pressure (MAP) (77 ± 6 → 95 ± 8 mm Hg) and CPP (52 ± 7 → 70 ± 7 mm Hg). ICP was unchanged during infusion of phenylephrine (25 ± 1 vs. 25 ± 2 mm Hg). The phenylephrine infusion was stopped after 45 minutes and MAP returned to baseline (76 ± 8 mm Hg). We conclude that phenylephrine increased CPP because of its effect on MAP, but did not alter ICP. Phenylephrine may be used to increase CPP without raising ICP when autoregulation is intact.