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BackgroundIndicators to evaluate progress towards timely access to safe surgical, anaesthesia, and obstetric (SAO) care were proposed in 2015 by the Lancet Commission on Global Surgery. These aimed to capture access to surgery, surgical workforce, surgical volume, perioperative mortality rate, and catastrophic and impoverishing financial consequences of surgery. Despite being rapidly taken up by practitioners, data points from which to derive the indicators were not defined, limiting comparability across time or settings. We convened global experts to evaluate and explicitly define-for the first time-the indicators to improve comparability and support achievement of 2030 goals to improve access to safe affordable surgical and anaesthesia care globally.Methods and findingsThe Utstein process for developing and reporting guidelines through a consensus building process was followed. In-person discussions at a 2-day meeting were followed by an iterative process conducted by email and virtual group meetings until consensus was reached. The meeting was held between June 16 to 18, 2019; discussions continued until August 2020. Participants consisted of experts in surgery, anaesthesia, and obstetric care, data science, and health indicators from high-, middle-, and low-income countries. Considering each of the 6 indicators in turn, we refined overarching descriptions and agreed upon data points needed for construction of each indicator at current time (basic data points), and as each evolves over 2 to 5 (intermediate) and >5 year (full) time frames. We removed one of the original 6 indicators (one of 2 financial risk protection indicators was eliminated) and refined descriptions and defined data points required to construct the 5 remaining indicators: geospatial access, workforce, surgical volume, perioperative mortality, and catastrophic expenditure. A strength of the process was the number of people from global institutes and multilateral agencies involved in the collection and reporting of global health metrics; a limitation was the limited number of participants from low- or middle-income countries-who only made up 21% of the total attendees.ConclusionsTo track global progress towards timely access to quality SAO care, these indicators-at the basic level-should be implemented universally as soon as possible. Intermediate and full indicator sets should be achieved by all countries over time. Meanwhile, these evolutions can assist in the short term in developing national surgical plans and collecting more detailed data for research studies.

PurposeDelaying cataract surgery is associated with an increased risk of falls, but whether routine preoperative testing delays cataract surgery long enough to cause clinical harm is unknown. We sought to determine whether the use of routine preoperative testing leads to harm in the form of delayed surgery and falls in Medicare beneficiaries awaiting cataract surgery.DesignRetrospective, observational cohort study using 2006-2014 Medicare claims.ParticipantsMedicare beneficiaries 66+ years of age with a Current Procedural Terminology claim for ocular biometry.MethodsWe measured the mean and median number of days between biometry and cataract surgery, calculated the proportion of patients waiting ≥ 30 days or ≥ 90 days for surgery, and determined the odds of sustaining a fall within 90 days of biometry among patients of high-testing physicians (testing performed in ≥ 75% of their patients) compared with patients of low-testing physicians. We also estimated the number of days of delay attributable to high-testing physicians.Main outcome measuresIncidence of falls occurring between biometry and surgery, odds of falling within 90 days of biometry, and estimated delay associated with physician testing behavior.ResultsOf 248 345 beneficiaries, 16.4% were patients of high-testing physicians. More patients of high-testing physicians waited ≥ 30 days and ≥ 90 days to undergo surgery (31.4% and 8.2% vs. 25.0% and 5.5%, respectively; P < 0.0001 for both). Falls before surgery in patients of high-testing physicians increased by 43% within the 90 days after ocular biometry (1.0% vs. 0.7%; P < 0.0001). The adjusted odds ratio of falling within 90 days of biometry in patients of high-testing physicians versus low-testing physicians was 1.10 (95% confidence interval [CI], 1.03-1.19; P = 0.008). After adjusting for surgical wait time, the odds ratio decreased to 1.07 (95% CI, 1.00-1.15; P = 0.06). The delay associated with having a high-testing physician was approximately 8 days (estimate, 7.97 days; 95% CI, 6.40-9.55 days; P < 0.0001). Other factors associated with delayed surgery included patient race (non-White), Northeast region, ophthalmologist ≤ 40 years of age, and low surgical volume.ConclusionsOveruse of routine preoperative medical testing by high-testing physicians is associated with delayed surgery and increased falls in cataract patients awaiting surgery.

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.

BACKGROUND:Capnography is universally accepted as an essential patient safety monitor in high-income countries (HICs) yet is often unavailable in low and middle-income countries (LMICs). Increasing capnography availability has been proposed as one of many potential approaches to improving perioperative outcomes in LMICs. This scoping review summarises the existing literature on the effect of capnography on patient outcomes to help prioritise interventions and guide expansion of capnography in LMICs. METHODS:We searched MEDLINE and EMBASE databases for articles published between 1980 and March 2019. Studies that assessed the impact of capnography on morbidity, mortality, or the use of airway interventions both inside and outside the operating room were included. RESULTS:The search resulted in 7445 unique papers, and 31 were included for analysis. Retrospective and non-randomised data suggest capnography use may improve outcomes in the operating room, ICU, and emergency department, and during resuscitation. Prospective data on capnography use for procedural sedation suggest earlier detection of hypoventilation and a reduction in haemoglobin desaturation events. No randomised studies exist that assess the impact of capnography on patient outcomes. CONCLUSION:Despite widespread endorsement of capnography as a mandatory perioperative monitor, rigorous data demonstrating its impact on patient outcomes are limited, especially in LMICs. The association between capnography use and a reduction in serious airway complications suggests that closing the capnography gap in LMICs may represent a significant opportunity to improve patient safety. Additional data are needed to quantify the global capnography gap and better understand the barriers to capnography scale-up in LMICs.

IntroductionMedication errors (MEs), which occur commonly in the perioperative period, have the potential to cause patient harm or death. Many published recommendations exist for preventing perioperative MEs; however, many of these recommendations conflict and are often not applicable to middle-income and low-income countries. The goal of this study is to develop and disseminate consensus-based recommendations for perioperative medication safety that are tailored to country income level.Methods and analysisThe primary site of this mixed-methods study is Massachusetts General Hospital/Harvard Medical School. Participants include a minimum of 108 international medication safety experts, 27 from each of the World Bank's four country income groups (high, upper-middle, lower-middle and low-income). Using the Delphi method, participants will rate the appropriateness of candidate medication safety recommendations by completing online surveys using RedCAP. We will use Condorcet ranking methods to prioritise the final recommendations for each country income group. We will execute a comprehensive dissemination strategy for the recommendations across each country income group. Finally, we will conduct semistructured interviews with our participants to evaluate the initial adoption and implementation of the recommendations in each country income group.Ethics and disseminationThis study was approved by the Human Research Committee/Institutional Review Board at Partners Healthcare (2019P003567). Findings will be published in peer-reviewed journals and presented at local and international conferences.Trial registration numberNCT04240301.

PurposePerioperative 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 vs calculated 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.MethodsOver 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.ResultsSix 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] vs 1 [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).ConclusionsPatients 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.

BackgroundThe effect of choice of anesthesia on clinical outcome for endovascular treatment (EVT) in patients with acute ischemic stroke (AIS) remains unclear.MethodsWe conducted a pilot trial of 43 patients with acute anterior circulation ischemic stroke having EVT. Patients were randomly allocated to receive general anesthesia or conscious sedation. We documented the rate of recruitment and rate of conversion from conscious sedation to general anesthesia. In addition, we recorded the change in National Institute of Health stroke scale (NIHSS) on day 7, the rate of successful reperfusion and measured neurological function by certified researchers using modified Rankin Score (mRS 0 to 2) at 90 days.ResultsThe recruitment rate was 31.4% and majority of patients were excluded because of delay in hospital presentation and posterior circulation stroke. The rate of conversion from conscious sedation to general anesthesia was 18.2%. This was primarily related to excessive sedation and uncontrolled movement. Change in NIHSS score, rate of successful reperfusion and functional recovery were similar between groups.ConclusionsIt was feasible to randomize AIS patients receiving either general anesthesia or conscious sedation for EVT.

The increasing focus on and importance of surgical care in achieving universal health coverage requires the development of safe and accessible anaesthesia services. Increasing access to care by supporting the necessary inputs to the anaesthesia system, including medications, equipment and personnel, must be accompanied by processes that support high-quality care, including support for education, and guidelines for standards, and training. As safe, high-quality care requires an integrated approach, each element must be supported together, i.e., in an integrated manner to ensure that anaesthesia care reaches those who need it, and in the safest possible manner. Several important efforts have been undertaken globally to address and foster these elements, and resources to guide these processes exist for low- and middle-income countries to improve them. This review highlights both the needs and resources for safe and high-quality care that patients deserve.

BACKGROUND:In Africa, most countries have fewer than 1 physician anesthesiologist (PA) per 100,000 population. Nonphysician anesthesia providers (NPAPs) play a large role in the workforce of many low- and middle-income countries (LMICs), but little information has been systematically collected to describe existing human resources for anesthesia care models. An understanding of existing PA and NPAP training pathways and roles is needed to inform anesthesia workforce planning, especially for critically underresourced countries. METHODS:Between 2016 and 2018, we conducted electronic, phone, and in-person surveys of anesthesia providers in Africa. The surveys focused on the presence of anesthesia training programs, training program characteristics, and clinical scope of practice after graduation. RESULTS:One hundred thirty-one respondents completed surveys representing data for 51 of 55 countries in Africa. Most countries had both PA and NPAP training programs (57%; mean, 1.6 pathways per country). Thirty distinct training pathways to become an anesthesia provider could be discriminated on the basis of entry qualification, duration, and qualification gained. Of these 30 distinct pathways, 22 (73%) were for NPAPs. Physician and NPAP program durations were a median of 48 and 24 months (ranges: 36-72, 9-48), respectively. Sixty percent of NPAP pathways required a nursing background for entry, and 60% conferred a technical (eg, diploma/license) qualification after training. Physicians and NPAPs were trained to perform most anesthesia tasks independently, though few had subspecialty training (such as regional or cardiac anesthesia). CONCLUSIONS:Despite profound anesthesia provider shortages throughout Africa, most countries have both NPAP and PA training programs. NPAP training pathways, in particular, show significant heterogeneity despite relatively similar scopes of clinical practice for NPAPs after graduation. Such heterogeneity may reflect the varied needs and resources for different settings, though may also suggest lack of consensus on how to train the anesthesia workforce. Lack of consistent terminology to describe the anesthesia workforce is a significant challenge that must be addressed to accelerate workforce research and planning efforts.

BackgroundMidazolam has been found to exacerbate or unmask limb motor dysfunction in patients with brain tumors. This study aimed to determine whether the exacerbated upper limb motor-sensory deficits are mediated through benzodiazepine sites by demonstrating reversibility by flumazenil in patients with gliomas in eloquent areas.MethodsThis was an interventional, parallel assignment, nonrandomized trial. Study subjects were admitted in the operating room. Patients with supratentorial eloquent area gliomas and volunteers of similar age without neurologic disease were sedated with midazolam, but still responsive and cooperative. Motor and sensory functions for upper extremities were evaluated by the Nine-Hole Peg Test before and after midazolam, as well as after flumazenil reversal.ResultsThirty-two cases were included: 15 in the glioma group and 17 in the control group. The total dose of midazolam and flumazenil were comparable between the groups. In the glioma group, the times to task completion after midazolam in the contralateral hand (P = 0.001) and ipsilateral hand (P = 0.002) were 26.5 (95% CI, 11.3 to 41.7) and 13.7 (95% CI, 5.0 to 22.4) seconds slower than baseline, respectively. After flumazenil reversal, the contralateral hand (P = 0.99) and ipsilateral hand (P = 0.187) performed 1.2 (95% CI, -3.3 to 5.8) and 1.5 (95% CI, -0.5 to 3.5) seconds slower than baseline, respectively. In the control group, the dominant (P < 0.001) and nondominant hand (P = 0.006) were 2.9 (95% CI, 1.4 to 4.3) and 1.7 (95% CI, 0.5 to 2.9) seconds slower than baseline, respectively. After flumazenil, the dominant hand (P = 0.99) and nondominant hand (P = 0.019) performed 0.2 (95% CI, -0.7 to 1.0) and 1.3 (95% CI, -0.2 to 2.4) seconds faster than baseline, respectively.ConclusionsIn patients with eloquent area gliomas, mild sedation with midazolam induced motor coordination deficits in upper limbs. This deficit was almost completely reversed by the benzodiazepine antagonist flumazenil, suggesting that this is a reversible abnormality linked to occupation of the receptor by midazolam.

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.

We sought to characterize stroke management and outcomes in a postoperative population. By using the electronic medical records, we identified 39 patients suffering perioperative stroke after noncardiac and nonneurosurgical procedures for whom documentation of management and outcomes was available. Thirty-three strokes occurred during admission, whereas 6 occurred after discharge and were recognized upon return to the hospital. Perioperative stroke was associated with delayed recognition, infrequent intervention, and significant rates of morbidity and mortality, suggesting the need for improved screening and more rapid treatment. There may be disparities in care and outcomes between in-hospital and out-of hospital stroke patients, though further study is warranted.

The co-occurrence of primary brain tumor and pregnancy poses unique challenges to the treating physician. If a rapidly growing lesion causes life-threatening mass effect, craniotomy for tumor debulking becomes urgent. The choice between awake craniotomy versus general anesthesia becomes complicated if the tumor is encroaching on eloquent brain because considerations pertinent to both patient safety and oncological outcome, in addition to fetal wellbeing, are involved. A 31-year-old female at 30 weeks gestation with twins presented to our hospital seeking awake craniotomy to resect a 7 × 6 × 5 cm left frontoparietal brain tumor with 7 mm left-to-right subfalcine herniation on imaging that led to word finding difficulty, dysfluency, right upper extremity paralysis, and right lower extremity weakness. She had twice undergone tumor debulking under general anesthesia during the same pregnancy at an outside hospital at 16 weeks and 28 weeks gestation. There were considerations both for and against awake brain tumor resection over surgery under general anesthesia. The decision-making process and the technical nuances related to awake brain tumor resection in this neurologically impaired patient are discussed. Awake craniotomy benefits the patient who harbors a tumor that encroaches on the eloquent brain by allowing a greater extent of resection while preserving the language and sensorimotor function. It can be successfully done in pregnant patients who are neurologically impaired. The patient should be motivated and well informed of the details of the process. A multidisciplinary and collaborative effort is also crucial.

Communication between brain areas and how they are influenced by changes in consciousness are not fully understood. One hypothesis is that brain areas communicate via oscillatory processes, utilizing network-specific frequency bands, that can be measured with metrics that reflect between-region interactions, such as coherence and phase amplitude coupling (PAC). To evaluate this hypothesis and understand how these interactions are modulated by state changes, we analyzed electrophysiological recordings in humans at different nodes of one well-studied brain network: the basal ganglia-thalamocortical loops of the motor system during loss of consciousness induced by anesthesia. We recorded simultaneous electrocorticography over primary motor cortex (M1) with local field potentials from subcortical motor regions (either basal ganglia or thalamus) in 15 movement disorder patients during anesthesia (propofol) induction as a part of their surgery for deep brain stimulation. We observed reduced coherence and PAC between M1 and the subcortical nuclei, which was specific to the beta band (∼18-24 Hz). The fact that this pattern occurs selectively in beta underscores the importance of this frequency band in the motor system and supports the idea that oscillatory interactions at specific frequencies are related to the capacity for normal brain function and behavior.

Cerebral ischemia is the pathophysiological condition in which the oxygenated cerebral blood flow is less than what is needed to meet cerebral metabolic demand. It is one of the most debilitating complications in the perioperative period and has serious clinical sequelae. The monitoring and prevention of intraoperative cerebral ischemia are crucial because an anesthetized patient in the operating room cannot be neurologically assessed. In this paper, we provide an overview of the definition, etiology, risk factors, and prevention of cerebral ischemia during surgery.

BackgroundWe hypothesized that the addition of dexmedetomidine in a clinically relevant dose to propofol-remifentanil anesthesia regimen does not exert an adverse effect on motor-evoked potentials (MEP) and somatosensory-evoked potentials (SSEP) in adult patients undergoing thoracic spinal cord tumor resection.MethodsSeventy-one adult patients were randomized into three groups. Propofol group (n = 25): propofol-remifentanil regimenand the dosage was adjusted to maintain the bispectral index (BIS) between 40 and 50. DP adjusted group (n = 23): Dexmedetomidine (0.5 μg/kg loading dose infused over 10 min followed by a constant infusion of 0.5 μg/kg/h) was added to the propofol-remifentanil regimen and propofol was adjusted to maintain BIS between 40 and 50. DP unadjusted group (n = 23): Dexmedetomidine (administer as DP adjusted group) was added to the propofol-remifentanil regimen and propofol was not adjusted. All patients received MEP, SSEP and BIS monitoring.ResultsThere were no significant changes in the amplitude and latency of MEP and SSEP among different groups (P > 0.05). The estimated propofol plasma concentration in DP adjusted group (2.7 ± 0.3 μg/ml) was significantly lower than in propofol group (3.1 ± 0.2 μg/ml) and DP unadjusted group (3.1 ± 0.2 μg/ml) (P = 0.000). BIS in DP unadjusted group (35 ± 5) was significantly lower than in propofol group (44 ± 3) (P = 0.000).ConclusionsThe addition of dexmedetomidine to propofol-remifentanil regimen does not exert an adverse effect on MEP and SSEP monitoring in adult patients undergoing thoracic spinal cord tumor resection.Trial registrationThe study was registered with the Chinese Clinical Trial Registry on January 31st, 2014. The reference number was ChiCTR-TRC-14004229.

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.

IntroductionMentorship in medicine is associated with increased career satisfaction and personal development. Despite these benefits, little is known about mentorship in anesthesiology training programs. Our objectives were to determine (1) the prevalence of formal mentorship programs among anesthesiology training programs in Canada, (2) the prevalence of informal and formal mentorship among anesthesiology residents in Canada, and (3) the predictors of having an identified mentor among anesthesiology residents in Canada.MethodsWe conducted a cross-sectional web-based survey of residents and program directors from Canadian anesthesiology residency programs. Program directors were questioned about formal mentorship programs, and residents were asked to provide demographic data and information about their mentorship relationships. We analyzed the relationship between resident characteristics and mentorship.ResultsOur survey response rates were 76% and 39% for the Program Director Survey and the Resident Survey, respectively. Formal mentorship programs were present in 54% of residency training programs, and 94% of residents agreed that mentorship was important. Seventy-four percent of residents identified at least one mentor, although 42% of these residents did not interact regularly with their mentor. Mentors and mentees were more likely to be of the same gender. If a formal mentorship program was present, residents were more likely to identify a mentor (82 vs 17%) and interact regularly with their mentor (70 vs 46%).ConclusionsFormal mentorship programs were present in half of anesthesiology training programs. Although 74% of the residents identified a mentor, 42% did not interact regularly with their mentor. The presence of a formal mentorship program was positively associated with mentorship.

BackgroundRoutine preoperative testing is not recommended for patients undergoing cataract surgery, because testing neither decreases adverse events nor improves outcomes. We sought to assess adherence to this guideline, estimate expenditures from potentially unnecessary testing, and identify patient and health care system characteristics associated with potentially unnecessary testing.MethodsUsing an observational cohort of Medicare beneficiaries undergoing cataract surgery in 2011, we determined the prevalence and cost of preoperative testing in the month before surgery. We compared the prevalence of preoperative testing and office visits with the mean percentage of beneficiaries who underwent tests and had office visits during the preceding 11 months. Using multivariate hierarchical analyses, we examined the relationship between preoperative testing and characteristics of patients, health system characteristics, surgical setting, care team, and occurrence of a preoperative office visit.ResultsOf 440,857 patients, 53% had at least one preoperative test in the month before surgery. Expenditures on testing during that month were $4.8 million higher and expenditures on office visits $12.4 million higher (42% and 78% higher, respectively) than the mean monthly expenditures during the preceding 11 months. Testing varied widely among ophthalmologists; 36% of ophthalmologists ordered preoperative tests for more than 75% of their patients. A patient's probability of undergoing testing was associated mainly with the ophthalmologist who managed the preoperative evaluation.ConclusionsPreoperative testing before cataract surgery occurred frequently and was more strongly associated with provider practice patterns than with patient characteristics. (Funded by the Foundation for Anesthesia Education and Research and the Grove Foundation.).

Organ protection and physiology optimization are important goals when taking care of anesthetized patients undergoing surgery. Postoperative cognitive dysfunction and perioperative stroke are unwarranted potential outcomes. Neurovascular coupling, the match between cerebral metabolic demand and substrate supply, should be regarded as the essential cerebral physiology which needs to be monitored during surgery. The brain-targeting near-infrared spectroscopy (NIRS) technology has the potential to fulfill this goal. Proposition of why and how to monitor essential cerebral physiology via advanced NIRS technologies is discussed. We also discussed the limits of the current NIRS technologies which merely measure cerebral tissue oxygen saturation in pooled cerebral arterial, capillary, and venous blood. © 2013 Copyright SPIE.

BackgroundMultiple studies have shown that cerebral tissue oxygen saturation () is decreased after phenylephrine treatment. We hypothesized that the negative impact of phenylephrine administration on is affected by arterial blood carbon dioxide partial pressure () because CO2 is a powerful modulator of cerebrovascular tone.MethodsIn 14 anaesthetized healthy patients, i.v. phenylephrine bolus was administered to increase the mean arterial pressure ∼20–30% during hypocapnia, normocapnia, and hypercapnia. and cerebral blood volume (CBV) were measured using frequency domain near-infrared spectroscopy, a quantitative technology. Data collection occurred before and after each treatment.ResultsPhenylephrine caused a significant decrease in during hypocapnia [=−3.4 (1.5)%, P

PurposeDuring anesthesia, maneuvers which cause the least disturbance of cerebral oxygenation with the greatest decrease in intracranial pressure would be most beneficial to patients with intracranial hypertension. Both head-up tilt (HUT) and hyperventilation are used to decrease brain bulk, and both may be associated with decreases in cerebral oxygenation. In this observational study, our null hypothesis was that the impact of HUT and hyperventilation on cerebral tissue oxygen saturation (SctO2) and cerebral blood volume (CBV) are comparable.MethodsSurgical patients without neurological disease were anesthetized with propofol-remifentanil. Before the start of surgery, frequency-domain near-infrared spectroscopy was used to measure SctO2 and CBV at the supine position, at the 30° head-up and head-down positions, as well as during hypoventilation and hyperventilation.ResultsThirty-three patients were studied. Both HUT and hyperventilation induced small decreases in SctO2 [3.5 (2.6)%; P