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1.
Anesthesiology ; 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31789635

RESUMO

There is intense debate around the use of altered and waived consent for pragmatic trials. Those in favor argue that traditional consent compromises the internal and external validity of these trials. Those against, warn that the resultant loss of autonomy compromises respect for persons and could undermine trust in the research enterprise.This article examines whether international ethical guidelines and the policy frameworks in three countries-the United States, England, and Australia-permit altered and waived consent for minimal-risk pragmatic trials conducted outside the emergency setting. Provisions for both are clearly articulated in U.S. regulations, but many countries do not have equivalent frameworks. Investigators should not assume that all consent models permitted in the United States are legal in their jurisdictions, even if they are deemed ethically defensible.The authors summarize ethical and regulatory considerations and present a framework for investigators contemplating trials with altered or waived consent.

2.
Anesthesiology ; 2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31789639

RESUMO

WHAT WE ALREADY KNOW ABOUT THIS TOPIC: Arterial pressure is a complex signal that is characterized by three primary components - systolic, diastolic, and mean pressure, along with a derived component, pulse pressure (systolic minus diastolic pressure)Each blood pressure component reflects distinct hemodynamic variables, and therefore presumably differently influences perfusion of various organsPrevious work identifies associations between intraoperative systolic and mean hypotension with myocardial and kidney injury WHAT THIS ARTICLE TELLS US THAT IS NEW: For each blood pressure component, the authors report significant and clinically meaningful associations between the lowest pressure sustained for 5 min and myocardial and kidney injuryAbsolute population risk thresholds were similar for myocardial and kidney injury, being roughly 90 mmHg for systolic, 65 mmHg for mean, 50 mmHg for diastolic, and 35 mmHg for pulse pressuresThe odds for myocardial and kidney injury progressively increased with duration and severity of hypotension below each threshold, even after adjusting for potential baseline confounding factors BACKGROUND:: Arterial pressure is a complex signal that can be characterized by systolic, mean, and diastolic components, along with pulse pressure (difference between systolic and diastolic pressures). The authors separately evaluated the strength of associations among intraoperative pressure components with myocardial and kidney injury after noncardiac surgery. METHODS: The authors included 23,140 noncardiac surgery patients at Cleveland Clinic who had blood pressure recorded at 1-min intervals from radial arterial catheters. The authors used univariable smoothing and multivariable logistic regression to estimate probabilities of each outcome as function of patients' lowest pressure for a cumulative 5 min for each component, comparing discriminative ability using C-statistics. The authors further assessed the association between outcomes and both area and minutes under derived thresholds corresponding to the beginning of increased risk for the average patient. RESULTS: Out of 23,140 patients analyzed, myocardial injury occurred in 6.1% and acute kidney injury in 8.2%. Based on the lowest patient blood pressure experienced for greater than or equal to 5 min, estimated thresholds below which the odds of myocardial or kidney injury progressively increased (slope P < 0.001) were 90 mmHg for systolic, 65 mmHg for mean, 50 mmHg for diastolic, and 35 mmHg for pulse pressure. Weak discriminative ability was noted between the pressure components, with univariable C-statistics ranging from 0.55 to 0.59. Area under the curve in the highest (deepest) quartile of exposure below the respective thresholds had significantly higher odds of myocardial injury after noncardiac surgery and acute kidney injury compared to no exposure for systolic, mean, and pulse pressure (all P < 0.001), but not diastolic, after adjusting for confounding. CONCLUSIONS: Systolic, mean, and pulse pressure hypotension were comparable in their strength of association with myocardial and renal injury. In contrast, the relationship with diastolic pressure was poor. Baseline factors were much more strongly associated with myocardial and renal injury than intraoperative blood pressure, but pressure differs in being modifiable.

3.
Anesth Analg ; 129(6): 1468-1473, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31743165

RESUMO

BACKGROUND: Pain after cardiac surgery is largely treated with opioids, but their poor safety profile makes nonopioid medications attractive as part of multimodal pathways. Anti-inflammatory drugs reduce acute postoperative pain, but the role of steroids in reducing acute poststernotomy pain is unclear. We evaluated the association between the intraoperative administration of methylprednisolone and postoperative analgesia, defined as a composite of pain scores and opioid consumption, during the initial 24 hours after cardiac surgery. METHODS: We conducted a post hoc retrospective analysis of a large clinical trial in which adults having cardiac surgery were randomized 1:1 to receive 2 intraoperative doses of 250 mg IV methylprednisolone or placebo. Pain scores and opioid consumption were collected during the initial 24 hours after surgery. Methylprednisolone was considered to be associated with better pain control than placebo if proven noninferior (not worse) on both pain scores (defined a priori with delta of 1 point) and opioid consumption (delta of 20%) and superior to placebo in at least 1 of the 2 outcomes. This test was repeated in the opposite direction (testing whether placebo is better than methylprednisolone on postoperative pain management). RESULTS: Of 251 eligible patients, 127 received methylprednisolone and 124 received placebo. Methylprednisolone was noninferior to placebo on pain with difference in mean (CI) pain scores of -0.25 (-0.71 to 0.21); P < .001. However, methylprednisolone was not noninferior to placebo on opioid consumption (ratio of geometric means [CI]: 1.11 [0.64-1.91]; P = .37). Because methylprednisolone was not noninferior to placebo on both outcomes, we did not proceed to superiority testing based on the a priori stopping rules. Similar results were found when testing the opposite direction. CONCLUSIONS: In this post hoc analysis, we could not identify a beneficial analgesic effect after cardiac surgery associated with methylprednisolone administration. There are currently no data to suggest that methylprednisolone has significant analgesic benefit in adults having cardiac surgery.

4.
Anesth Analg ; 2019 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-31725024

RESUMO

BACKGROUND: Postoperative delirium is common in critically ill patients, with a reported incidence of 11%-43%, and is associated with significant morbidity and cost. Perioperative hypotension and consequent brain hypoperfusion may contribute. We, therefore, tested the hypotheses that intraoperative and postoperative hypotension are associated with critical care delirium. METHODS: We included 1083 postoperative patients who were admitted directly from an operating room to the surgical intensive care unit. Delirium was assessed with the Confusion Assessment Method for Intensive Care Unit patients at 12-hour intervals. We used a confounder-adjusted Cox proportional hazard survival model to assess the association between the amount of intraoperative hypotension, which was measured as the time-weighted average of mean arterial pressure <65 mm Hg, and delirium while in critical care. Thereafter, we used a Cox model with the lowest mean arterial pressure on each intensive care day as a time-varying covariate to assess the relationship between critical care hypotension and delirium, adjusted for confounders and amount of intraoperative hypotension. RESULTS: Three hundred seventy-seven (35%) patients had delirium within the first 5 postoperative days in the surgical intensive care unit. Intraoperative hypotension was moderately associated with higher odds of postoperative delirium. The adjusted hazard ratio associated with 1 mm Hg increase in time-weighted average of mean arterial pressure <65 mm Hg was 1.11 (95% confidence interval [CI], 1.03-1.20; P = .008). Postoperatively, a 10 mm Hg reduction in the lowest mean pressure on each day in the critical care unit was significantly associated with a higher hazard of delirium, with an adjusted hazard ratio 1.12 (95% CI, 1.04-1.20; P = .003). CONCLUSIONS: Both intraoperative and postoperative hypotension are associated with delirium in postoperative critical care patients. The extent to which these relationships are causal remains unknown, but to the extent that they are, hypotension prevention may help reduce delirium and should be studied in prospective clinical trials.

5.
Anesthesiology ; 2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31651439

RESUMO

WHAT WE ALREADY KNOW ABOUT THIS TOPIC: Low vitamin D is common in the general populationIn nonsurgical populations, low 25-hydroxyvitamin D is associated with hypertension, left ventricular hypertrophy, heart failure, and coronary artery diseaseIn nonsurgical populations, low vitamin D concentrations are also associated with increased risk of some infections and renal injury WHAT THIS ARTICLE TELLS US THAT IS NEW: Vitamin D deficiency was common in this surgical populationPreoperative vitamin D was not associated with a composite of postoperative 30-day cardiac outcomesThere was an association between low vitamin D and a composite of infectious complications, and also evidence for an association with decreased kidney function BACKGROUND:: Low 25-hydroxyvitamin D is associated with cardiovascular, renal, and infectious risks. Postsurgical patients are susceptible to similar complications, but whether vitamin D deficiency contributes to postoperative complications remains unclear. We tested whether low preoperative vitamin D is associated with cardiovascular events within 30 days after noncardiac surgery. METHODS: We evaluated a subset of patients enrolled in the biobank substudy of the Vascular events In noncardiac Surgery patIents cOhort evaluatioN (VISION) study, who were at least 45 yr with at least an overnight hospitalization. Blood was collected preoperatively, and 25-hydroxyvitamin D was measured in stored samples. The primary outcome was the composite of cardiovascular events (death, myocardial injury, nonfatal cardiac arrest, stroke, congestive heart failure) within 30 postoperative days. Secondary outcomes were kidney injury and infectious complications. RESULTS: A total of 3,851 participants were eligible for analysis. Preoperative 25-hydroxyvitamin D concentration was 70 ± 30 nmol/l, and 62% of patients were vitamin D deficient. Overall, 26 (0.7%) patients died, 41 (1.1%) had congestive heart failure or nonfatal cardiac arrest, 540 (14%) had myocardial injury, and 15 (0.4%) had strokes. Preoperative vitamin D concentration was not associated with the primary outcome (average relative effect odds ratio [95% CI]: 0.93 [0.85, 1.01] per 10 nmol/l increase in preoperative vitamin D, P = 0.095). However, it was associated with postoperative infection (average relative effect odds ratio [95% CI]: 0.94 [0.90, 0.98] per 10 nmol/l increase in preoperative vitamin D, P adjusted value = 0.005) and kidney function (estimated mean change in postoperative estimated glomerular filtration rate [95% CI]: 0.29 [0.11, 0.48] ml · min · 1.73 m per 10 nmol/l increase in preoperative vitamin D, P adjusted value = 0.004). CONCLUSIONS: Preoperative vitamin D was not associated with a composite of postoperative 30-day cardiac outcomes. However, there was a significant association between vitamin D deficiency and a composite of infectious complications and decreased kidney function. While renal effects were not clinically meaningful, the effect of vitamin D supplementation on infectious complications requires further study.

6.
Lancet ; 394(10212): 1907-1914, 2019 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-31645286

RESUMO

BACKGROUND: An association between increasing anaesthetic depth and decreased postoperative survival has been shown in observational studies; however, evidence from randomised controlled trials is lacking. Our aim was to compare all-cause 1-year mortality in older patients having major surgery and randomly assigned to light or deep general anaesthesia. METHODS: In an international trial, we recruited patients from 73 centres in seven countries who were aged 60 years and older, with significant comorbidity, having surgery with expected duration of more than 2 h, and an anticipated hospital stay of at least 2 days. We randomly assigned patients who had increased risk of complications after major surgery to receive light general anaesthesia (bispectral index [BIS] target 50) or deep general anaesthesia (BIS target 35). Anaesthetists also nominated an appropriate range for mean arterial pressure for each patient during surgery. Patients were randomly assigned in permuted blocks by region immediately before surgery, with the patient and assessors masked to group allocation. The primary outcome was 1-year all-cause mortality. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12612000632897, and is closed to accrual. FINDINGS: Patients were enrolled between Dec 19, 2012, and Dec 12, 2017. Of the 18 026 patients screened as eligible, 6644 were enrolled, randomly assigned to treatment or control, and formed the intention-to-treat population (3316 in the BIS 50 group and 3328 in the BIS 35 group). The median BIS was 47·2 (IQR 43·7 to 50·5) in the BIS 50 group and 38·8 (36·3 to 42·4) in the BIS 35 group. Mean arterial pressure was 3·5 mm Hg (4%) higher (median 84·5 [IQR 78·0 to 91·3] and 81·0 [75·4 to 87·6], respectively) and volatile anaesthetic use was 0·26 minimum alveolar concentration (30%) lower (0·62 [0·52 to 0·73] and 0·88 [0·74 to 1·04], respectively) in the BIS 50 than the BIS 35 group. 1-year mortality was 6·5% (212 patients) in the BIS 50 group and 7·2% (238 patients) in the BIS 35 group (hazard ratio 0·88, 95% CI 0·73 to 1·07, absolute risk reduction 0·8%, 95% CI -0·5 to 2·0). Grade 3 adverse events occurred in 954 (29%) patients in the BIS 50 group and 909 (27%) patients in the BIS 35 group; and grade 4 adverse events in 265 (8%) and 259 (8%) patients, respectively. The most commonly reported adverse events were infections, vascular disorders, cardiac disorders, and neoplasms. INTERPRETATION: Among patients at increased risk of complications after major surgery, light general anaesthesia was not associated with lower 1-year mortality than deep general anaesthesia. Our trial defines a broad range of anaesthetic depth over which anaesthesia may be safely delivered when titrating volatile anaesthetic concentrations using a processed electroencephalographic monitor. FUNDING: Health Research Council of New Zealand; National Health and Medical Research Council, Australia; Research Grant Council of Hong Kong; National Institute for Health and Research, UK; and National Institutes of Health, USA.

7.
Lancet ; 394(10211): 1807-1815, 2019 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-31645288

RESUMO

BACKGROUND: Three perioperative factors impair host defence against recurrence during cancer surgery: the surgical stress response, use of volatile anaesthetic, and opioids for analgesia. All factors are ameliorated by regional anaesthesia-analgesia. We tested the primary hypothesis that breast cancer recurrence after potentially curative surgery is lower with regional anaesthesia-analgesia using paravertebral blocks and the anaesthetic propofol than with general anaesthesia with the volatile anaesthetic sevoflurane and opioid analgesia. A second hypothesis was that regional anaesthesia-analgesia reduces persistent incisional pain. METHODS: We did a randomised controlled trial at 13 hospitals in Argentina, Austria, China, Germany, Ireland, New Zealand, Singapore, and the USA. Women (age <85 years) having potentially curative primary breast cancer resections were randomised by computer to either regional anaesthesia-analgesia (paravertebral blocks and propofol) or general anaesthesia (sevoflurane) and opioid analgesia. The primary outcome was local or metastatic breast cancer recurrence. The secondary outcome was incisional pain at 6 months and 12 months. Primary analyses were done under intention-to-treat principles. This trial is registered with ClinicalTrials.gov, NCT00418457. The study was stopped after a preplanned futility boundary was crossed. FINDINGS: Between Jan 30, 2007, and Jan 18, 2018, 2132 women were enrolled to the study, of whom 24 were excluded before surgery. 1043 were assigned to regional anaesthesia-analgesia and 1065 were allocated to general anaesthesia. Baseline characteristics were well balanced between study groups. Median follow-up was 36 (IQR 24-49) months. Among women assigned regional anaesthesia-analgesia, 102 (10%) recurrences were reported, compared with 111 (10%) recurrences among those allocated general anaesthesia (hazard ratio 0·97, 95% CI 0·74-1·28; p=0·84). Incisional pain was reported by 442 (52%) of 856 patients assigned to regional anaesthesia-analgesia and 456 (52%) of 872 patients allocated to general anaesthesia at 6 months, and by 239 (28%) of 854 patients and 232 (27%) of 852 patients, respectively, at 12 months (overall interim-adjusted odds ratio 1·00, 95% CI 0·85-1·17; p=0·99). Neuropathic breast pain did not differ by anaesthetic technique and was reported by 87 (10%) of 859 patients assigned to regional anaesthesia-analgesia and 89 (10%) of 870 patients allocated to general anaesthesia at 6 months, and by 57 (7%) of 857 patients and 57 (7%) of 854 patients, respectively, at 12 months. INTERPRETATION: In our study population, regional anaesthesia-analgesia (paravertebral block and propofol) did not reduce breast cancer recurrence after potentially curative surgery compared with volatile anaesthesia (sevoflurane) and opioids. The frequency and severity of persistent incisional breast pain was unaffected by anaesthetic technique. Clinicians can use regional or general anaesthesia with respect to breast cancer recurrence and persistent incisional pain. FUNDING: Sisk Healthcare Foundation (Ireland), Eccles Breast Cancer Research Fund, British Journal of Anaesthesia International, College of Anaesthetists of Ireland, Peking Union Medical College Hospital, Science Fund for Junior Faculty 2016, Central Bank of Austria, and National Healthcare Group.


Assuntos
Anestesia por Condução/métodos , Anestesia Geral/métodos , Neoplasias da Mama/cirurgia , Recidiva Local de Neoplasia/prevenção & controle , Adulto , Idoso , Idoso de 80 Anos ou mais , Analgésicos Opioides/efeitos adversos , Analgésicos Opioides/uso terapêutico , Anestesia por Condução/efeitos adversos , Anestesia Geral/efeitos adversos , Anestésicos Inalatórios/efeitos adversos , Neoplasias da Mama/patologia , Feminino , Seguimentos , Humanos , Estimativa de Kaplan-Meier , Metástase Linfática , Mastectomia/métodos , Pessoa de Meia-Idade , Gradação de Tumores , Recidiva Local de Neoplasia/etiologia , Estadiamento de Neoplasias , Bloqueio Nervoso/métodos , Dor Pós-Operatória/prevenção & controle , Sevoflurano/efeitos adversos
8.
Anesth Analg ; 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31490816

RESUMO

BACKGROUND: Continuous blood pressure monitoring may facilitate early detection and prompt treatment of hypotension. We tested the hypothesis that area under the curve (AUC) mean arterial pressure (MAP) <65 mm Hg is reduced by continuous invasive arterial pressure monitoring. METHODS: Adults having noncardiac surgery were randomly assigned to continuous invasive arterial pressure or intermittent oscillometric blood pressure monitoring. Arterial catheter pressures were recorded at 1-minute intervals; oscillometric pressures were typically recorded at 5-minute intervals. We estimated the arterial catheter effect on AUC-MAP <65 mm Hg using a multivariable proportional odds model adjusting for imbalanced baseline variables and duration of surgery. Pressures <65 mm Hg were categorized as 0, 1-17, 18-91, and >91 mm Hg × minutes of AUC-MAP <65 mm Hg (ie, no hypotension and 3 equally sized groups of increasing hypotension). RESULTS: One hundred fifty-two patients were randomly assigned to arterial catheter use and 154 to oscillometric monitoring. For various clinical reasons, 143 patients received an arterial catheter, while 163 were monitored oscillometrically. There were a median [Q1, Q3] of 246 [187, 308] pressure measurements in patients with arterial catheters versus 55 (46, 75) measurements in patients monitored oscillometrically. In the primary intent-to-treat analysis, catheter-based monitoring increased detection of AUC-MAP <65 mm Hg, with an estimated proportional odds ratio (ie, odds of being in a worse hypotension category) of 1.78 (95% confidence interval [CI], 1.18-2.70; P = .006). The result was robust over an as-treated analysis and for sensitivity analyses with thresholds of 60 and 70 mm Hg. CONCLUSIONS: Intraoperative blood pressure monitoring with arterial catheters detected nearly twice as much hypotension as oscillometric measurements.

9.
Anesth Analg ; 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31490254

RESUMO

BACKGROUND: Perioperative hyperoxia has been recommended by the World Health Organization and the Centers for Disease Control and Prevention for the prevention of surgical site infections. Based on animal studies and physiological concerns, the kidneys and heart may be at risk from hyperoxia. We therefore conducted 2 unplanned subanalyses of a previous alternating cohort trial in which patients having colorectal surgery were assigned to either 30% or 80% inspired intraoperative oxygen. Specifically, we tested 2 coprimary hypotheses: (1) hyperoxia increases the incidence of acute kidney injury (AKI) within 7 postoperative days (PODs); and (2) hyperoxia worsens a composite of myocardial injury, in-hospital cardiac arrest, and 30-day mortality. METHODS: The underlying controlled trial included 5749 colorectal surgeries in 4481 patients, with the exposure alternating between 30% and 80% fraction of inspired oxygen (FIO2) during general anesthesia at 2-week intervals over a period of 39 months. AKI was defined as a 1.5-fold increase in creatinine from the preoperative level to the highest value measured during the initial 7 PODs. Myocardial injury was defined by fourth-generation troponin-T level >0.03 ng/mL. We assessed the effect of 80% vs 30% oxygen on the outcomes using generalized estimating equation (GEE) logistic models that adjusted for the possible within-patient correlation across multiple potential operations for a patient on different visits. RESULTS: For the AKI outcome, 2522 surgeries were allocated to 80% oxygen and 2552 to 30% oxygen. Hyperoxia had no effect on the primary outcome of postoperative AKI, with an incidence of 7.7% in the 80% oxygen group and 7.7% in the 30% oxygen group (relative risk = 0.99; 95% confidence interval [CI], 0.82-1.2; P = .95). One thousand six hundred forty-seven surgeries (all with scheduled troponin monitoring) were analyzed for the composite cardiovascular outcome. Hyperoxia had no effect on the collapsed composite of myocardial injury, cardiac arrest, and 30-day mortality, nor on any of its components (estimated relative risk = 0.71; 95% CI, 0.44-1.16; P = .17). CONCLUSIONS: We found no evidence that intraoperative hyperoxia causes AKI or cardiovascular complications in adults undergoing colorectal surgery. Consequently, we suggest that clinicians select intraoperative inspired oxygen fraction based on other considerations.

10.
Anesth Analg ; 129(3): 896-904, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31425235

RESUMO

BACKGROUND: Hypotension is associated with acute kidney injury, but vasopressors used to treat hypotension may also compromise renal function. We therefore tested the hypothesis that vasopressor infusion during complex spine surgery is not associated with impaired renal function. METHODS: In this retrospective cohort analysis, we considered adults who had complex spine surgery between January 2005 and September 2014 at the Cleveland Clinic Main Campus. Our primary outcome was postoperative estimated glomerular filtration rate. Secondarily, we evaluated renal function using Acute Kidney Injury Network criteria. We obtained data for 1814 surgeries, including 689 patients (38%) who were given intraoperative vasopressors infusion for ≥30 minutes and 1125 patients (62%) who were not. Five hundred forty patients with and 540 patients without vasopressor infusions were well matched across 32 potential confounding variables. RESULTS: In matched patients, vasopressor infusions lasted an average of 173 ± 100 minutes (SD) and were given a median dose (1st quintile, 3rd quintile) of 3.4-mg (1.5, 6.7 mg) phenylephrine equivalents. Mean arterial pressure and the amounts of hypotension were similar in each matched group. The postoperative difference in mean estimated glomerular filtration rate in patients with and without vasopressor infusions was only 0.8 mL/min/1.73 m (95% CI, -0.6 to 2.2 mL/min/1.73 m) (P = .28). Intraoperative vasopressor infusion was also not associated with increased odds of augmented acute kidney injury stage. CONCLUSIONS: Clinicians should not avoid typical perioperative doses of vasopressors for fear of promoting kidney injury. Tolerating hypotension to avoid vasopressor use would probably be a poor strategy.

11.
BMC Anesthesiol ; 19(1): 126, 2019 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-31288741

RESUMO

BACKGROUND: We previously reported that each 100 mg dL- 1 reduction in blood glucose over the range from ≈90 to > 300 mg dL- 1 decreases the shivering threshold (triggering core temperature) in rabbits by 1 °C. However, the effects of lower blood glucose concentrations has yet to be evaluated. We thus evaluated the relationship between the shivering threshold and blood glucose concentration over the mild-to-severe hypoglycemic range. METHODS: Thirty-nine rabbits were lightly anaesthetized with isoflurane and randomly assigned to one of the three groups: 1) severe hypoglycemia, insulin and dextrose infusions titrated to achieve blood glucose concentration at 45-75 mg dL- 1; 2) mild hypoglycemia, insulin and dextrose infusions titrated to achieve blood glucose concentration at 75-100 mg dL- 1; and 3) saline infusion. Cooling by colonic perfusion of water at 10 °C was continued until shivering occurred or esophageal core temperatures reached to 34 °C. RESULTS: The shivering threshold in the severe hypoglycemic rabbits was 35.7 ± 1.1 °C (mean ± SD); the thresholds in the mild hypoglycemic rabbits was 37.0 ± 0.7 °C; and the threshold in the control rabbits was 37.9 ± 1.0 °C. The shivering threshold increased linearly with blood glucose concentration: shivering threshold (°C) = 0.032 ∙ [blood glucose concentration (mg dL- 1)] + 34.1, R2 = 0.45. The shivering threshold thus decreased by approximately 1 °C for each 31 mg dL- 1 decrease in blood glucose concentration. CONCLUSIONS: There was a linear relationship between blood glucose and the shivering threshold over the range from severe hypoglycemia to normoglycemia. Blood glucose perturbations in the hypoglycemic range reduced the shivering threshold about three times as much as previously reported for the hyperglycemic range.

12.
J Clin Monit Comput ; 2019 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-31327102

RESUMO

Monitors that estimate nociception during anesthesia may be used to guide opioid and other analgesics administration to optimize anesthesia care and possibly outcome. We reviewed the literature to evaluate current evidence of the effect of nociception-guided management over standard anesthesia practice during surgery. A systematic review of the literature on the effect of nociception monitoring on anesthesia practice was conducted. Reports were eligible if they compared nociception-guided anesthesia to standard practice during surgery. Primary endpoint of this review is intraoperative opioid consumption. Secondary endpoints included hemodynamic control, postoperative pain and pain treatment. We identified 12 randomized controlled trials that compared one of five different nociception monitoring techniques to standard anesthesia care. Most studies were single center studies of small sample size. Six studies reported intraoperative opioid consumption as primary outcome. There was considerable variability with respect to surgical procedure and anesthesia technique. For nociception monitors that were investigated by more than one study, analysis of the pooled data was performed. The surgical plethysmographic index was the only monitor for which an intra operative opioid sparing effect was found. For the other monitors, either no effect was detected, or pooled analysis could not be performed due to paucity of study data. On secondary outcomes, no consistent effect of nociception-guided anesthesia could be established. Although some nociception monitors show promising results, no definitive conclusions regarding the effect of nociception monitoring on intraoperative opioid consumption or other anesthesia related outcome can be drawn.Clinical trial number PROSPERO ID 102913.

13.
Trials ; 20(1): 255, 2019 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-31053082

RESUMO

BACKGROUND: Hypotension is associated with serious complications, including myocardial infarction, acute kidney injury, and mortality. Consequently, predicting and preventing hypotension may improve outcomes. We will therefore determine if use of a novel hypotension prediction tool reduces the duration and severity of hypotension in patients having non-cardiac surgery. METHODS/DESIGN: We will conduct a two-center, pragmatic, randomized controlled trial (N = 213) in noncardiac surgical patients > 45 years old who require intra-arterial blood pressure monitoring. All participating patients will be connected to a Flortrac IQ sensor and EV1000 platform (Edwards Lifesciences, Irvine). They will be randomly assigned to blinded or unblinded arms. The Hypotension Prediction Index (HPI) and advanced hemodynamic information will be universally recorded, but will only be available to clinicians when patients are assigned to unblinded monitoring. The primary outcome will be the effect of HPI software guidance on intraoperative time-weighted average mean arterial pressure under a threshold of 65 mmHg, which will be assessed with a Wilcoxon-Mann-Whitney 2-sample, two-tailed test. DISCUSSION: Our trial will determine whether the Hypotension Prediction Index and associated hemodynamic information substantively reduces hypotension during non-cardiac surgery. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03610165 . Registered on 1 August 2018.

14.
Anesth Analg ; 128(6): 1160-1166, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31094783

RESUMO

BACKGROUND: Postoperative pain is common and promotes opioid use. Surgical wounds are hypoxic because normal perfusion is impaired. Local wound ischemia and acidosis promote incisional pain. Some evidence suggests that improving oxygen supply to surgical wounds might reduce pain. We therefore tested the hypothesis that supplemental (80% inspired) intraoperative oxygen reduces postoperative pain and opioid consumption. METHODS: We conducted a post hoc analysis of a large, single-center alternating cohort trial allocating surgical patients having general anesthesia for colorectal surgery to either 30% or 80% intraoperative oxygen concentration in 2-week blocks for a total of 39 months. Irrespective of allocation, patients were given sufficient oxygen to maintain saturation ≥95%. Patients who had regional anesthesia or nerve blocks were excluded. The primary outcome was pain and opioid consumption during the initial 2 postoperative hours, analyzed jointly. The secondary outcome was pain and opioid consumption over the subsequent 24 postoperative hours. Subgroup analyses of the primary outcome were conducted for open versus laparoscopic procedures and for patients with versus without chronic pain. RESULTS: A total of 4702 cases were eligible for analysis: 2415 were assigned to 80% oxygen and 2287 to 30% oxygen. The groups were well balanced on potential confounding factors. Average pain scores and opioid consumption were similar between the groups (mean difference in pain scores, -0.01 [97.5% CI, -0.16 to 0.14; P = .45], median difference in opioid consumption, 0.0 [97.5% CI, 0 to 0] mg morphine equivalents; P = .82). There were also no significant differences in the secondary outcome or subgroup analyses. CONCLUSIONS: Supplemental intraoperative oxygen does not reduce acute postoperative pain or reduce opioid consumption.

16.
Crit Care Med ; 47(7): 910-917, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30985388

RESUMO

OBJECTIVES: Hypotension thresholds that provoke renal injury, myocardial injury, and mortality in critical care patients remain unknown. We primarily sought to determine the relationship between hypotension and a composite of myocardial injury (troponin T ≥ 0.03 ng/mL without nonischemic cause) and death up to 7 postoperative days. Secondarily, we considered acute kidney injury (creatinine concentration ≥ 0.3 mg/dL or 1.5 times baseline). DESIGN: Retrospective cohort. SETTING: Surgical ICU at an academic medical center. PATIENTS: Two-thousand eight-hundred thirty-three postoperative patients admitted to the surgical ICU. INTERVENTIONS: A Cox proportional hazard survival model was used to assess the association between lowest mean arterial pressure on each intensive care day, considered as a time-varying covariate, and outcomes. In sensitivity analyses hypotension defined as pressures less than 80 mm Hg and 70 mm Hg were also considered. MEASUREMENTS AND MAIN RESULTS: There was a strong nonlinear (quadratic) association between the lowest mean arterial pressure and the primary outcome of myocardial injury after noncardiac surgery or mortality, with estimated risk increasing at lower pressures. The risk of myocardial injury after noncardiac surgery or mortality was an estimated 23% higher at the 25th percentile (78 mm Hg) of lowest mean arterial pressure compared with at the median of 87 mm Hg, with adjusted hazard ratio (95% CI) of 1.23 (1.12-1.355; p < 0.001). Overall results were generally similar in sensitivity analyses based on every hour of mean arterial pressure less than 80 mm Hg and any mean arterial pressure less than 70 mm Hg. Post hoc analyses showed that the relationship between ICU hypotension and outcomes depended on the amount of intraoperative hypotension. The risk of acute kidney injury increased over a range of minimum daily pressures from 110 mm Hg to 50 mm Hg, with an adjusted hazard ratio of 1.27 (95% CI, 1.18-1.37; p < 0.001). CONCLUSIONS: Increasing amounts of hypotension (defined by lowest mean arterial pressures per day) were strongly associated with myocardial injury, mortality, and renal injury in postoperative critical care patients.

17.
Anesthesiology ; 131(1): 74-83, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30998509

RESUMO

BACKGROUND: Normal blood pressure varies among individuals and over the circadian cycle. Preinduction blood pressure may not be representative of a patient's normal blood pressure profile and cannot give an indication of a patient's usual range of blood pressures. This study therefore aimed to determine the relationship between ambulatory mean arterial pressure and preinduction, postinduction, and intraoperative mean arterial pressures. METHODS: Ambulatory (automated oscillometric measurements at 30-min intervals) and preinduction, postinduction, and intraoperative mean arterial pressures (1-min intervals) were prospectively measured and compared in 370 American Society of Anesthesiology physical status classification I or II patients aged 40 to 65 yr having elective noncardiac surgery with general anesthesia. RESULTS: There was only a weak correlation between the first preinduction and mean daytime mean arterial pressure (r = 0.429, P < 0.001). The difference between the first preinduction and mean daytime mean arterial pressure varied considerably among individuals. In about two thirds of the patients, the lowest postinduction and intraoperative mean arterial pressures were lower than the lowest nighttime mean arterial pressure. The difference between the lowest nighttime mean arterial pressure and a mean arterial pressure of 65 mmHg varied considerably among individuals. The lowest nighttime mean arterial pressure was higher than 65 mmHg in 263 patients (71%). CONCLUSIONS: Preinduction mean arterial pressure cannot be used as a surrogate for the normal daytime mean arterial pressure. The lowest postinduction and intraoperative mean arterial pressures are lower than the lowest nighttime mean arterial pressure in most patients.

18.
Anesth Analg ; 129(2): 618-633, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31008746

RESUMO

Perioperative investigators and professionals increasingly seek to evaluate whether implementing systematic practice changes improves outcomes compared to a previous routine. Cluster randomized trials are the optimal design to assess a systematic practice change but are often impractical; investigators, therefore, often select a before-after design. In this Statistical Grand Rounds, we first discuss biases inherent in a before-after design, including confounding due to periods being completely separated by time, regression to the mean, the Hawthorne effect, and others. Many of these biases can be at least partially addressed by using appropriate designs and analyses, which we discuss. Our focus is on segmented regression of an interrupted time series, which does not require a concurrent control group; we also present alternative designs including difference-in-difference, stepped wedge, and cluster randomization. Conducting segmented regression well requires a sufficient number of time points within each period, along with a robust set of potentially confounding variables. This method compares preintervention and postintervention changes over time, divergences in the outcome when an intervention begins, and trends observed with the intervention compared to trends projected without it. Difference-in-difference methods add a concurrent control, enabling yet stronger inference. When done well, the discussed methods permit robust inference on the effect of an intervention, albeit still requiring assumptions and having limitations. Methods are demonstrated using an interrupted time series study in which anesthesiologists took responsibility for an adult medical emergency team from internal medicine physicians in an attempt to improve outcomes.

19.
Eur J Anaesthesiol ; 36(5): 320-326, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30865003

RESUMO

BACKGROUND: The WHO recommends routine intra-operative and early postoperative use of high inspired oxygen concentrations (hyperoxia). However, a high intra-operative inspired oxygen fraction (FiO2) might result in an increased risk of postoperative respiratory complications. AIM: To test the hypothesis that intra-operative FiO2 of 80% compared with 30% inspired oxygen decreases the postoperative ratio of arterial saturation to fraction of inspired oxygen (SpO2/FiO2). Secondarily, to evaluate whether an intra-operative inspired FiO2 of 80% increases the incidence of pulmonary complications. DESIGN: Posthoc subanalysis of a large alternating cohort trial. SETTING: Cleveland Clinic, Cleveland, United States, from 2013 to 2016. PATIENTS: Adults having colorectal surgery. Cases lasting less than 2 h, re-operations on the same hospitalisation, and cases with missing intra-operative or postoperative data were excluded. INTERVENTION: Maintaining intra-operative FiO2 at 30 or 80% and alternating this management every 2 weeks for a study period of 39 months. MAIN OUTCOME: Minimal SpO2/FiO2 ratio value in the postanaesthesia care unit. Secondary outcome was a composite of postoperative pulmonary complications throughout hospitalisation. RESULTS: A total of 5056 patients were included. Groups were well balanced on all demographic, baseline and procedural variables. Median time-weighted averages of intra-operative FiO2 in the 30 and 80% groups were 43% (IQR 38 to 54%, N=2486) and 81% (IQR 78 to 82%, N=2570), respectively. No difference was found in the lowest SpO2/FiO2 ratio (estimated median difference 0 [95% confidence interval: 0, 0], P = 0.91). The incidence of postoperative pulmonary complications was 16.3 and 17.6% in the 30 and 80% FiO2 groups, respectively (relative risk 1.07 [95% confidence interval: 0.95, 1.21], P = 0.25). CONCLUSION: Intra-operative hyperoxia did not change the postoperative SpO2/FiO2 ratio or the risk for pulmonary complications. Clinicians should not refrain from using hyperoxia for fear of provoking respiratory complications. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01777568.

20.
Anesth Analg ; 2019 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-30882520

RESUMO

BACKGROUND: We previously reported that the duration of hospitalization was not different between isoflurane and sevoflurane. But more plausible consequences of using soluble volatile anesthetics are delayed emergence from anesthesia and prolonged stays in the postanesthesia care unit (PACU). We therefore compared isoflurane and sevoflurane on emergence time and PACU duration. METHODS: We reanalyzed data from 1498 adults who participated in a previous alternating intervention trial comparing isoflurane and sevoflurane. Patients, mostly having colorectal surgery, were assigned to either volatile anesthetic in 2-week blocks that alternated for half a year. Emergence time was defined as the time from minimum alveolar concentration fraction reaching 0.3 at the end of the procedure until patients left the operating room. PACU duration was defined from admission to the end of phase 1 recovery. Treatment effect was assessed using Cox proportional hazards regression, adjusted for imbalanced baseline variables. RESULTS: A total of 674 patients were given isoflurane, and 824 sevoflurane. Emergence time was slightly longer for isoflurane with a median (quartiles) of 16 minutes (12-22 minutes) versus 14 minutes (11-19 minutes) for sevoflurane, with an adjusted hazard ratio of 0.81 (97.5% CI, 0.71-0.92; P < .001). Duration in the PACU did not differ, with a median (quartiles) of 2.6 hours (2.0-3.6 hours) for isoflurane and 2.6 hours (2.0-3.7 hours) hours for sevoflurane. The adjusted hazard ratio for PACU discharge time was 1.04 (97.5% CI, 0.91-1.18; P= .56). CONCLUSIONS: Isoflurane prolonged emergence by only 2 minutes, which is not a clinically important amount, and did not prolong length of stay in the PACU. The more soluble and much less-expensive anesthetic isoflurane thus seems to be a reasonable alternative to sevoflurane.

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