1
|
Ma K, Bebawy JF. Anemia and Optimal Transfusion Thresholds in Brain-Injured Patients: A Narrative Review of the Literature. Anesth Analg 2024; 138:992-1002. [PMID: 38109853 DOI: 10.1213/ane.0000000000006772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
Anemia is a highly prevalent condition that may compromise oxygen delivery to vital organs, especially among the critically ill. Although current evidence supports the adoption of a restrictive transfusion strategy and threshold among the nonbleeding critically ill patient, it remains unclear whether this practice should apply to the brain-injured patient, given the predisposition to cerebral ischemia in this patient population, in which even nonprofound anemia may exert a detrimental effect on clinical outcomes. The purpose of this review is to provide an overview of the pathophysiological changes related to impaired cerebral oxygenation in the brain-injured patient and to present the available evidence on the effect of anemia and varying transfusion thresholds on the clinical outcomes of patients with acute brain injury.
Collapse
Affiliation(s)
- Kan Ma
- From the Department of Anesthesiology and Pain Medicine, St Michael's Hospital, University of Toronto, Toronto, Ontario, Canada
| | - John F Bebawy
- Department of Anesthesiology and Neurological Surgery, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| |
Collapse
|
2
|
Dolmans RG, Hulsbergen AF, Gormley WB, Broekman ML. Routine Blood Tests for Severe Traumatic Brain Injury: Can They Predict Outcomes? World Neurosurg 2020; 136:e60-e67. [DOI: 10.1016/j.wneu.2019.10.086] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 10/13/2019] [Accepted: 10/14/2019] [Indexed: 01/18/2023]
|
3
|
Maegele M, Schöchl H, Menovsky T, Maréchal H, Marklund N, Buki A, Stanworth S. Coagulopathy and haemorrhagic progression in traumatic brain injury: advances in mechanisms, diagnosis, and management. Lancet Neurol 2017; 16:630-647. [PMID: 28721927 DOI: 10.1016/s1474-4422(17)30197-7] [Citation(s) in RCA: 189] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 05/08/2017] [Accepted: 05/30/2017] [Indexed: 01/28/2023]
Abstract
Normal haemostasis depends on an intricate balance between mechanisms of bleeding and mechanisms of thrombosis, and this balance can be altered after traumatic brain injury (TBI). Impaired haemostasis could exacerbate the primary insult with risk of initiation or aggravation of bleeding; anticoagulant use at the time of injury can also contribute to bleeding risk after TBI. Many patients with TBI have abnormalities on conventional coagulation tests at admission to the emergency department, and the presence of coagulopathy is associated with increased morbidity and mortality. Further blood testing often reveals a range of changes affecting platelet numbers and function, procoagulant or anticoagulant factors, fibrinolysis, and interactions between the coagulation system and the vascular endothelium, brain tissue, inflammatory mechanisms, and blood flow dynamics. However, the degree to which these coagulation abnormalities affect TBI outcomes and whether they are modifiable risk factors are not known. Although the main challenge for management is to address the risk of hypocoagulopathy with prolonged bleeding and progression of haemorrhagic lesions, the risk of hypercoagulopathy with an increased prothrombotic tendency also warrants consideration.
Collapse
Affiliation(s)
- Marc Maegele
- Department for Trauma and Orthopaedic Surgery, Cologne-Merheim Medical Center, University Witten/Herdecke, Cologne, Germany; Institute for Research in Operative Medicine, University Witten/Herdecke, Cologne, Germany.
| | - Herbert Schöchl
- Department for Anaesthesiology and Intensive Care Medicine, AUVA Trauma Academic Teaching Hospital, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Tomas Menovsky
- Department for Neurosurgery, Antwerp University Hospital, University of Antwerp, Edegem, Belgium
| | - Hugues Maréchal
- Department of Anaesthesiology and Intensive Care Medicine, CRH La Citadelle, Liège, Belgium
| | - Niklas Marklund
- Department of Clinical Sciences, Division of Neurosurgery, University Hospital of Southern Sweden, Lund University, Lund, Sweden
| | - Andras Buki
- Department of Neurosurgery, The MTA-PTE Clinical Neuroscience MR Research Group, Janos Szentagothai Research Center, Hungarian Brain Research Program, University of Pécs, Pécs, Hungary
| | - Simon Stanworth
- NHS Blood and Transplant/Oxford University Hospitals NHS Foundation Trust, University of Oxford, John Radcliffe Hospital, Oxford, UK
| |
Collapse
|
4
|
Travers S, Martin S, Litofsky NS. The effects of anaemia and transfusion on patients with traumatic brain injury: A review. Brain Inj 2016; 30:1525-1532. [PMID: 27680103 DOI: 10.1080/02699052.2016.1199907] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Anaemia in traumatic brain injury (TBI) is frequently encountered. Neurosurgical texts continue to recommend transfusion for hematocrit below 30%, despite clear evidence to do so. Transfusion should increase oxygen delivery to the brain, but it may also increase morbidity and mortality. METHODS This study reviewed the relevant literature to better understand the risks of anaemia and benefits of correction of anaemia by transfusion. RESULTS Of the 21 studies reviewed, eight found that anaemia was harmful to patients with TBI; five found no significant outcome; seven found transfusion was associated with higher rates of morbidity and mortality; two found that transfusion lowered mortality and increased brain tissue oxygen levels; and ten found no correlation between transfusion and outcome. However, the levels of anaemia severity and the outcome measurements varied widely and the majority of outcomes focused on crude measurements rather than detailed functional assessments. CONCLUSIONS No division of response based on gender difference or impact of anaemia in the post-hospital treatment setting was observed. A randomized control trial is recommended to determine the impact of anaemia and transfusion on detailed outcome assessment in comparison of transfusion thresholds ranging from ≤ 7 g dL-1 to ≤ 9 g dL-1 in patients with moderate-to-severe TBI.
Collapse
Affiliation(s)
- Sarah Travers
- a Division of Neurological Surgery , University of Missouri School of Medicine , Columbia , MO , USA
| | - Simon Martin
- a Division of Neurological Surgery , University of Missouri School of Medicine , Columbia , MO , USA
| | - N Scott Litofsky
- a Division of Neurological Surgery , University of Missouri School of Medicine , Columbia , MO , USA
| |
Collapse
|
5
|
Lelubre C, Bouzat P, Crippa IA, Taccone FS. Anemia management after acute brain injury. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2016; 20:152. [PMID: 27311626 PMCID: PMC4911680 DOI: 10.1186/s13054-016-1321-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Anemia is frequent among brain-injured patients, where it has been associated with an increased risk of poor outcome. The pathophysiology of anemia in this patient population remains multifactorial; moreover, whether anemia merely reflects a higher severity of the underlying disease or is a significant determinant of the neurological recovery of such patients remains unclear. Interestingly, the effects of red blood cell transfusions (RBCT) in moderately anemic patients remain controversial; although hemoglobin levels are increased, different studies observed only a modest and inconsistent improvement in cerebral oxygenation after RBCT and raised serious concerns about the risk of increased complications. Thus, considering this "blood transfusion anemia paradox", the optimal hemoglobin level to trigger RBCT in brain-injured patients has not been defined yet; also, there is insufficient evidence to provide strong recommendations regarding which hemoglobin level to target and which associated transfusion strategy (restrictive versus liberal) to select in this patient population. We summarize in this review article the more relevant studies evaluating the effects of anemia and RBCT in patients with an acute neurological condition; also, we propose some potential strategies to optimize transfusion management in such patients.
Collapse
Affiliation(s)
- Christophe Lelubre
- Department of Intensive Care, Hôpital Erasme, Université Libre de Bruxelles (ULB), Route de Lennik 808, 1070, Brussels, Belgium.,Laboratoire de Médecine Expérimentale, Université Libre de Bruxelles (ULB) - Unité 222, CHU Charleroi (Hôpital André Vésale), Rue de Gozée 706, Montigny-Le-Tilleul, Belgium
| | - Pierre Bouzat
- Department of Anaesthesiology and Critical Care, Grenoble University Hospital, Hôpital Albert Michallon, Avenue Maquis du Grésivaudan, Grenoble, F-38043, France.,Grenoble Neurosciences Institute, Grenoble Alpes University, Grenoble, F-38043, France
| | - Ilaria Alice Crippa
- Department of Intensive Care, Hôpital Erasme, Université Libre de Bruxelles (ULB), Route de Lennik 808, 1070, Brussels, Belgium
| | - Fabio Silvio Taccone
- Department of Intensive Care, Hôpital Erasme, Université Libre de Bruxelles (ULB), Route de Lennik 808, 1070, Brussels, Belgium.
| |
Collapse
|
6
|
Boutin A, Chassé M, Shemilt M, Lauzier F, Moore L, Zarychanski R, Griesdale D, Desjardins P, Lacroix J, Fergusson D, Turgeon AF. Red Blood Cell Transfusion in Patients With Traumatic Brain Injury: A Systematic Review and Meta-Analysis. Transfus Med Rev 2015; 30:15-24. [PMID: 26409622 DOI: 10.1016/j.tmrv.2015.08.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 06/14/2015] [Accepted: 08/15/2015] [Indexed: 01/23/2023]
Abstract
Our objectives were to evaluate the frequency of red blood cell (RBC) transfusion in patients with traumatic brain injury (TBI) as well as potential determinants and outcomes associated with RBC transfusion in this population. We conducted a systematic review of cohort studies and randomized trials of patients with TBI. We searched Medline, Embase, the Cochrane Library, and BIOSIS databases from their inception up to April 2015. We selected studies of adult patients with acute TBI reporting data on RBC transfusions. Cumulative incidences of transfusion were pooled using random-effect models with a DerSimonian approach. To evaluate the association between RBC transfusion and potential determinants or clinical outcomes, we pooled risk ratios or mean differences with random-effect models and the Mantel-Haenszel method. We identified 24 eligible studies (17414 patients). After pooling data from 23 studies (7524 patients), approximately 36% (95% confidence interval [CI], 28-44; I(2) = 98%) of patients received RBC transfusion at some point during their hospital stay. Hemoglobin thresholds for transfusion were rarely available (reported in 9 studies) and varied from 6 to 10 g/dL. Glasgow Coma Scale scores at admission were lower in patients who were transfused than those who were not (3 cohort studies; 1371 patients; mean difference of 1.38 points [95% CI, 0.86-1.89]; I(2) = 12%). Mortality was not significantly different among transfused and nontransfused patients in univariate and multivariate meta-analyses. Hospital length of stay was longer among patients receiving RBC transfusion compared to those who did not (3 studies; n = 455; mean difference, 9.58 days [95% CI, 3.94-15.22]; I(2) = 74%). Results should be considered cautiously due to the high heterogeneity and high risk of confounding from the observational nature of included studies. Red blood cell transfusion is frequent in patients with TBI, and transfusion practices varied widely between studies. Current published data highlight the lack of clinical evidence guiding transfusion strategies in TBI.
Collapse
Affiliation(s)
- Amélie Boutin
- CHU de Québec-Université Laval Research Center (Hôpital de l'Enfant-Jésus), Population Health and Optimal Health Practices Research Unit, Université Laval, Quebec City, QC, Canada; Department of Social and Preventive Medicine, Université Laval, Quebec City, QC, Canada
| | - Michaël Chassé
- CHU de Québec-Université Laval Research Center (Hôpital de l'Enfant-Jésus), Population Health and Optimal Health Practices Research Unit, Université Laval, Quebec City, QC, Canada; Department of Anesthesiology and Critical Care Medicine, Division of Critical Care Medicine, Université Laval, Quebec City, QC, Canada
| | - Michèle Shemilt
- CHU de Québec-Université Laval Research Center (Hôpital de l'Enfant-Jésus), Population Health and Optimal Health Practices Research Unit, Université Laval, Quebec City, QC, Canada
| | - François Lauzier
- CHU de Québec-Université Laval Research Center (Hôpital de l'Enfant-Jésus), Population Health and Optimal Health Practices Research Unit, Université Laval, Quebec City, QC, Canada; Department of Anesthesiology and Critical Care Medicine, Division of Critical Care Medicine, Université Laval, Quebec City, QC, Canada; Department of Medicine, Université Laval, Quebec City, QC, Canada
| | - Lynne Moore
- CHU de Québec-Université Laval Research Center (Hôpital de l'Enfant-Jésus), Population Health and Optimal Health Practices Research Unit, Université Laval, Quebec City, QC, Canada; Department of Social and Preventive Medicine, Université Laval, Quebec City, QC, Canada
| | - Ryan Zarychanski
- Department of Internal Medicine, Sections of Critical Care Medicine and of Haematology & Medical Oncology, University of Manitoba, Winnipeg, MB, Canada
| | - Donald Griesdale
- Department of Anesthesia, University of British Columbia, Vancouver, BC, Canada
| | - Philippe Desjardins
- Department of Anesthesiology and Critical Care Medicine, Division of Critical Care Medicine, Université Laval, Quebec City, QC, Canada
| | - Jacques Lacroix
- Department of Pediatrics, Critical Care Medicine, Université de Montréal, Montreal, QC, Canada
| | - Dean Fergusson
- Clinical Epidemiology Unit, Ottawa Hospital Research Institute, Ottawa, ON, Canada
| | - Alexis F Turgeon
- CHU de Québec-Université Laval Research Center (Hôpital de l'Enfant-Jésus), Population Health and Optimal Health Practices Research Unit, Université Laval, Quebec City, QC, Canada; Department of Anesthesiology and Critical Care Medicine, Division of Critical Care Medicine, Université Laval, Quebec City, QC, Canada.
| |
Collapse
|
7
|
|
8
|
Abstract
PURPOSE OF REVIEW Anaemia is common among patients in the neurocritical care unit (NCCU) and is thought to exacerbate brain injury. However, the optimal haemoglobin (Hgb) level still remains to be elucidated for traumatic brain injury (TBI), subarachnoid haemorrhage (SAH) and acute ischaemic stroke (AIS). This review outlines recent studies about anaemia and the effects of red blood cell transfusion (RBCT) on outcome in TBI, SAH and AIS patients admitted to the NCCU. RECENT FINDINGS Patients with severe SAH, AIS and TBI often develop anaemia and require RBCT. In general critical care, a restrictive RBCT strategy (Hgb ~7 g/dl) is preferable in patients without serious cardiac disease. In severe TBI, AIS and SAH, both anaemia and RBCT may negatively influence clinical outcome. However, the appropriate RBCT trigger remains unclear and there is great variance in how these patients are transfused. There is evidence from PET and microdialysis studies in humans that RBCT can favourably influence brain metabolism and oxygenation. This correction of hypoxia or altered metabolism rather than anaemia may be of greater importance. SUMMARY Results from general critical care should not be extrapolated to all patients with acute brain injury. Transfusion is not risk free, but RBCT use needs to be considered also in terms of potential benefit.
Collapse
Affiliation(s)
- Peter LeRoux
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA 191406, USA.
| |
Collapse
|
9
|
Desjardins P, Turgeon AF, Tremblay MH, Lauzier F, Zarychanski R, Boutin A, Moore L, McIntyre LA, English SW, Rigamonti A, Lacroix J, Fergusson DA. Hemoglobin levels and transfusions in neurocritically ill patients: a systematic review of comparative studies. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2012; 16:R54. [PMID: 22471943 PMCID: PMC3681381 DOI: 10.1186/cc11293] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Revised: 02/09/2012] [Accepted: 04/02/2012] [Indexed: 02/07/2023]
Abstract
Introduction Accumulating evidence suggests that, in critically ill patients, a lower hemoglobin transfusion threshold is safe. However, the optimal hemoglobin level and associated transfusion threshold remain unknown in neurocritically ill patients. Methods We conducted a systematic review of comparative studies (randomized and nonrandomized) to evaluate the effect of hemoglobin levels on mortality, neurologic function, intensive care unit (ICU) and hospital length of stay, duration of mechanical ventilation, and multiple organ failure in adult and pediatric neurocritically ill patients. We searched MEDLINE, The Cochrane Central Register of Controlled Trials, Embase, Web of Knowledge, and Google Scholar. Studies focusing on any neurocritical care conditions were included. Data are presented by using odds ratios for dichotomous outcomes and mean differences for continuous outcomes. Results Among 4,310 retrieved records, six studies met inclusion criteria (n = 537). Four studies were conducted in traumatic brain injury (TBI), one in subarachnoid hemorrhage (SAH), and one in a mixed population of neurocritically ill patients. The minimal hemoglobin levels or transfusion thresholds ranged from 7 to 10 g/dl in the lower-Hb groups and from 9.3 to 11.5 g/dl in the higher-Hb groups. Three studies had a low risk of bias, and three had a high risk of bias. No effect was observed on mortality, duration of mechanical ventilation, or multiple organ failure. In studies reporting on length of stay (n = 4), one reported a significant shorter ICU stay (mean, -11.4 days (95% confidence interval, -16.1 to -6.7)), and one, a shorter hospital stay (mean, -5.7 days (-10.3 to -1.1)) in the lower-Hb groups, whereas the other two found no significant association. Conclusions We found insufficient evidence to confirm or refute a difference in effect between lower- and higher-Hb groups in neurocritically ill patients. Considering the lack of evidence regarding long-term neurologic functional outcomes and the high risk of bias of half the studies, no recommendation can be made regarding which hemoglobin level to target and which associated transfusion strategy (restrictive or liberal) to favor in neurocritically ill patients.
Collapse
Affiliation(s)
- Philippe Desjardins
- Department of Anesthesiology, Division of Critical Care Medicine, Faculty of Medicine, Université Laval, 1050, Avenue de Médecine, Pavillon Ferdinand-Vandry, Québec, QC, G1V 0A6, Canada
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Kramer AH, Le Roux P. Red Blood Cell Transfusion and Transfusion Alternatives in Traumatic Brain Injury. Curr Treat Options Neurol 2012; 14:150-163. [PMID: 22314930 DOI: 10.1007/s11940-012-0167-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OPINION STATEMENT: Anemia develops in about 50% of patients hospitalized with traumatic brain injury (TBI) and is recognized as a cause of secondary brain injury. This review examines the effects of anemia and transfusion on TBI patients through a literature search to identify original research on anemia and transfusion in TBI, the effects of transfusion on brain physiology, and the role of erythropoietin or hemoglobin-based blood substitutes (HBBSs). However, the amount of high-quality, prospective data available to help make decisions about when TBI patients should be transfused is very small. Randomized transfusion trials have involved far too few TBI patients to reach definitive conclusions. Thus, it is hardly surprising that there is widespread practice variation. In our opinion, a hemoglobin transfusion threshold of 7 g/dL cannot yet be considered safe for TBI patients admitted to hospital, and in particular to the ICU, as it is for other critically ill patients. Red blood cell transfusions often have immediate, seemingly beneficial effects on cerebral physiology, but the magnitude of this effect may depend in part upon how long the cells have been stored before administration. In light of existing physiological data, we generally aim to keep hemoglobin concentrations greater than 9 g/dL during the first several days after TBI. In part, the decision is based on the patient's risk of or development of secondary ischemia or brain injury. An increasing number of centers use multimodal neurologic monitoring, which may help to individualize transfusion goals based on the degree of cerebral hypoxia or metabolic distress. When available, brain tissue oxygen tension values less than 15-20 mm Hg or a lactate:pyruvate ratio greater than 30-40 would influence us to use more aggressive hemoglobin correction (e.g., a transfusion threshold of 10 g/dL). Clinicians can attempt to reduce transfusion requirements by limiting phlebotomy, minimizing hemodilution, and providing appropriate prophylaxis against gastrointestinal hemorrhage. Administration of exogenous erythropoietin may have a small impact in further reducing the need for transfusion, but it also may increase complications, most notably deep venous thrombosis. Erythropoietin is currently of great interest as a potential neuroprotective agent, but until it is adequately evaluated in randomized controlled trials, it should not be used routinely for this purpose. HBBSs are also of interest, but existing preparations have not been shown to be beneficial-or even safe-in the context of TBI.
Collapse
Affiliation(s)
- Andreas H Kramer
- Department of Critical Care Medicine & Clinical Neurosciences, University of Calgary, Ground Floor, McCaig Tower, 3134 Hospital Dr NW, Calgary, AB, T2N 2T9, Canada
| | | |
Collapse
|
11
|
Reduced brain tissue oxygen in traumatic brain injury: are most commonly used interventions successful? ACTA ACUST UNITED AC 2011; 70:535-46. [PMID: 21610340 DOI: 10.1097/ta.0b013e31820b59de] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Brain tissue oxygenation (PbtO2)-guided management facilitates treatment of reduced PbtO2 episodes potentially conferring survival and outcome advantages in severe traumatic brain injury (TBI). To date, the nature and effectiveness of commonly used interventions in correcting compromised PbtO2 in TBI remains unclear. We sought to identify the most common interventions used in episodes of compromised PbtO2 and to analyze which were effective. METHODS A retrospective 7-year review of consecutive severe TBI patients with a PbtO2 monitor was conducted in a Level I trauma center's intensive care unit or neurosurgical registry. Episodes of compromised PbtO2 (defined as <20 mm Hg for 0.25-4 hours) were identified, and clinical interventions conducted during these episodes were analyzed. Response to treatment was gauged on how rapidly (ΔT) PbtO2 normalized (>20 mm Hg) and how great the PbtO2 increase was (ΔPbtO2). Intracranial pressure (ΔICP) and cerebral perfusion pressure (ΔCPP) also were examined for these episodes. RESULTS Six hundred twenty-five episodes of reduced PbtO2 were identified in 92 patients. Patient characteristics were: age 41.2 years, 77.2% men, and Injury Severity Score and head or neck Abbreviated Injury Scale score of 34.0 ± 9.2 and 4.9 ± 0.4, respectively. Five interventions: narcotics or sedation, pressors, repositioning, FIO2/PEEP increases, and combined sedation or narcotics + pressors were the most commonly used strategies. Increasing the number of interventions resulted in worsening the time to PbtO2 correction. Triple combinations resulted in the lowest ΔICP and dual combinations in the highest ΔCPP (p < 0.05). CONCLUSION Clinicians use a limited number of interventions when correcting compromised PbtO2. Using strategies employing many interventions administered closely together may be less effective in correcting PbO2, ICP, and CPP deficits. Some PbtO2 deficits may be self-limited.
Collapse
|
12
|
Current world literature. Curr Opin Anaesthesiol 2011; 24:224-33. [PMID: 21386670 DOI: 10.1097/aco.0b013e32834585d6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|