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Chohan AS, Campbell BG, Martin LG. Anesthesia Case of the Month. J Am Vet Med Assoc 2022; 260:999-1002. [PMID: 35298405 DOI: 10.2460/javma.21.06.0306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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2
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Faraoni D, DiNardo JA. Red Blood Cell Transfusion and Adverse Outcomes in Pediatric Cardiac Surgery Patients: Where Does the Blame Lie? Anesth Analg 2021; 133:1074-1076. [PMID: 34673720 DOI: 10.1213/ane.0000000000005498] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- David Faraoni
- From the Division of Cardiac Anesthesia, Department of Anesthesia and Pain Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Anesthesiology and Pain Medicine, University of Toronto, Toronto, Ontario, Canada
| | - James A DiNardo
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
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Affiliation(s)
- Jean-Louis Vincent
- Department of Intensive Care, Erasme Hospital, Université libre de Bruxelles, Brussels, Belgium
| | - Alexandre Joosten
- Department of Anesthesiology, Erasme Hospital, Université Libre de Bruxelles, Brussels, Belgium
- Department of Anesthesiology and Intensive Care, Hôpitaux Universitaires Paris-Sud, Université Paris-Sud, Université Paris-Saclay, Paul Brousse Hospital, Assistance Publique Hôpitaux de Paris (APHP), Villejuif, France
| | - Bernd Saugel
- Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Durkin C, Romano K, Egan S, Lohser J. Hypoxemia During One-Lung Ventilation: Does It Really Matter? CURRENT ANESTHESIOLOGY REPORTS 2021; 11:414-420. [PMID: 34254003 PMCID: PMC8263011 DOI: 10.1007/s40140-021-00470-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2021] [Indexed: 12/20/2022]
Abstract
Purpose of Review Hypoxemia during one-lung ventilation, while decreasing in frequency, persists as an intraoperative challenge for anesthesiologists. Discerning when desaturation and resultant hypoxemia correlates to tissue hypoxia is challenging in the perioperative setting and requires a thorough understanding of the physiology of oxygen delivery and tissue utilization. Recent Findings Oxygen delivery is not directly correlated with peripheral oxygen saturation in patients undergoing one-lung ventilation, emphasizing the importance of hemoglobin concentration and cardiac output in avoiding tissue hypoxia. While healthy humans can tolerate acute hypoxemia without long-term consequences, there is a paucity of evidence from patients undergoing thoracic surgery. Increasingly recognized is the potential harm of hyperoxic states, particularly in the setting of complex patients with comorbid diseases. Summary Anesthesiologists are left to determine an acceptable oxygen saturation nadir that is individualized to the patient and procedure based on an understanding of oxygen supply, demand, and the consequences of interventions.
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Affiliation(s)
- Chris Durkin
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver General Hospital, JPP3 Room 3400, 899 West 12th Avenue, Vancouver, British Columbia V5Z-1M9 Canada
| | - Kali Romano
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver General Hospital, JPP3 Room 3400, 899 West 12th Avenue, Vancouver, British Columbia V5Z-1M9 Canada
| | - Sinead Egan
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver General Hospital, JPP3 Room 3400, 899 West 12th Avenue, Vancouver, British Columbia V5Z-1M9 Canada
| | - Jens Lohser
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver General Hospital, JPP3 Room 3400, 899 West 12th Avenue, Vancouver, British Columbia V5Z-1M9 Canada
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Abou-Arab O, Braik R, Huette P, Bouhemad B, Lorne E, Guinot PG. The ratios of central venous to arterial carbon dioxide content and tension to arteriovenous oxygen content are not associated with overall anaerobic metabolism in postoperative cardiac surgery patients. PLoS One 2018; 13:e0205950. [PMID: 30365515 PMCID: PMC6203355 DOI: 10.1371/journal.pone.0205950] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 10/04/2018] [Indexed: 12/03/2022] Open
Abstract
Background The aim of the present study was to evaluate the ability of the ratios of central venous to arterial carbon dioxide content and tension to arteriovenous oxygen content to predict an increase in oxygen consumption (VO2) upon fluid challenge (FC). Methods and results 110 patients admitted to cardiothoracic ICU and in whom the physician had decided to perform an FC (with 500 ml of Ringer's lactate solution) were included. The arterial pressure, cardiac index (Ci), and arterial and venous blood gas levels were measured before and after FC. VO2 and CO2-O2 derived variables were calculated. VO2 responders were defined as patients showing more than a 15% increase in VO2. Of the 92 FC responders, 43 (46%) were VO2 responders. At baseline, pCO2 gap, C(a-v)O2 were lower in VO2 responders than in VO2 non-responders, and central venous oxygen saturation (ScvO2) was higher in VO2 responders. FC was associated with an increase in MAP, SV, and CI in both groups. With regard to ScvO2, FC was associated with an increase in VO2 non-responders and a decrease in VO2 responders. FC was associated with a decrease in pvCO2 and pCO2 gap in VO2 non-responders only. The pCO2 gap/C(a-v)O2 ratio and C(a-v)CO2 content /C(a-v)O2 content ratio did not change with FC. The CO2 gap content/C(a-v)O2 content ratio and the C(a-v)CO2 content /C(a-v)O2 content ratio did not predict fluid-induced VO2 changes (area under the curve (AUC) [95% confidence interval (CI)] = 0.52 [0.39‒0.64] and 0.53 [0.4–0.65], respectively; p = 0.757 and 0.71, respectively). ScvO2 predicted an increase of more than 15% in the VO2 (AUC [95%CI] = 0.67 [0.55‒0.78]; p<0.0001). Conclusions Our results showed that the ratios of central venous to arterial carbon dioxide content and tension to arteriovenous oxygen content were not predictive of VO2 changes following fluid challenge in postoperative cardiac surgery patients.
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Affiliation(s)
- Osama Abou-Arab
- Anaesthesiology and Critical Care Department, Amiens University Hospital, Rond-point Fernand Leger, Amiens, France
| | - Rayan Braik
- Anaesthesiology and Critical Care Department, Amiens University Hospital, Rond-point Fernand Leger, Amiens, France
| | - Pierre Huette
- Anaesthesiology and Critical Care Department, Amiens University Hospital, Rond-point Fernand Leger, Amiens, France
| | - Belaid Bouhemad
- Anaesthesiology and Critical Care Department, Dijon University Hospital, 2 Bd Maréchal de Lattre de Tassigny, Dijon, France
| | - Emmanuel Lorne
- Anaesthesiology and Critical Care Department, Amiens University Hospital, Rond-point Fernand Leger, Amiens, France
| | - Pierre-Grégoire Guinot
- Anaesthesiology and Critical Care Department, Dijon University Hospital, 2 Bd Maréchal de Lattre de Tassigny, Dijon, France
- * E-mail:
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Du W, Long Y, Wang XT, Liu DW. The Use of the Ratio between the Veno-arterial Carbon Dioxide Difference and the Arterial-venous Oxygen Difference to Guide Resuscitation in Cardiac Surgery Patients with Hyperlactatemia and Normal Central Venous Oxygen Saturation. Chin Med J (Engl) 2016; 128:1306-13. [PMID: 25963349 PMCID: PMC4830308 DOI: 10.4103/0366-6999.156770] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Background: After cardiac surgery, central venous oxygen saturation (ScvO2) and serum lactate concentration are often used to guide resuscitation; however, neither are completely reliable indicators of global tissue hypoxia. This observational study aimed to establish whether the ratio between the veno-arterial carbon dioxide and the arterial-venous oxygen differences (P(v−a)CO2/C(a−v)O2) could predict whether patients would respond to resuscitation by increasing oxygen delivery (DO2). Methods: We selected 72 patients from a cohort of 290 who had undergone cardiac surgery in our institution between January 2012 and August 2014. The selected patients were managed postoperatively on the Intensive Care Unit, had a normal ScvO2, elevated serum lactate concentration, and responded to resuscitation by increasing DO2 by >10%. As a consequence, 48 patients responded with an increase in oxygen consumption (VO2) while VO2 was static or fell in 24. Results: At baseline and before resuscitative intervention in postoperative cardiac surgery patients, a P(v−a)CO2/C(a−v)O2 ratio ≥1.6 mmHg/ml predicted a positive VO2 response to an increase in DO2 of >10% with a sensitivity of 68.8% and a specificity of 87.5%. Conclusions: P(v−a)CO2/C(a−v)O2 ratio appears to be a reliable marker of global anaerobic metabolism and predicts response to DO2 challenge. Thus, patients likely to benefit from resuscitation can be identified promptly, the P(v−a)CO2/C(a−v)O2 ratio may, therefore, be a useful resuscitation target.
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Affiliation(s)
| | | | | | - Da-Wei Liu
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
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Cândido TD, Teixeira-Neto FJ, Diniz MS, Zanuzzo FS, Teixeira LR, Fantoni DT. Effects of a dexmedetomidine constant rate infusion and atropine on changes in global perfusion variables induced by hemorrhage followed by volume replacement in isoflurane-anesthetized dogs. Am J Vet Res 2015; 75:964-73. [PMID: 25350086 DOI: 10.2460/ajvr.75.11.964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate the effects of a dexmedetomidine constant rate infusion (CRI) and atropine on changes in global perfusion variables induced by hemorrhage and volume replacement (VR) in isoflurane-anesthetized dogs. ANIMALS 8 adult dogs. PROCEDURES Each dog was anesthetized twice, with a 2-week interval between anesthetic sessions. Anesthesia was maintained with 1.3 times the minimum alveolar concentration of isoflurane with and without dexmedetomidine (1.6 μg/kg, IV bolus, followed by 2 μg/kg/h, CRI). Dogs were mechanically ventilated and received an atracurium neuromuscular blockade during both sessions. During anesthesia with isoflurane and dexmedetomidine, atropine was administered 30 minutes before baseline measurements were obtained. After baseline data were recorded, 30% of the total blood volume was progressively withdrawn and VR was achieved with an equal proportion of autologous blood. RESULTS Following hemorrhage, cardiac index, oxygen delivery index, and mixed-venous oxygen saturation were significantly decreased and the oxygen extraction ratio was significantly increased from baseline. The anaerobic threshold was not achieved during either anesthetic session. When dogs were anesthetized with isoflurane and dexmedetomidine, they had a significantly lower heart rate, cardiac index, and mixed-venous oxygen saturation during VR than they did when anesthetized with isoflurane alone. Plasma lactate concentration, mixed venous-to-arterial carbon dioxide difference, base excess, and anion gap were unaltered by hemorrhage and VR and did not differ between anesthetic sessions. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the use of a dexmedetomidine CRI combined with atropine in isoflurane-anesthetized dogs that underwent volume-controlled hemorrhage followed by VR did not compromise global perfusion sufficiently to result in anaerobic metabolism.
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Affiliation(s)
- Thaísa D Cândido
- Departments of Anesthesiology, São Paulo State University, Botucatu, SP, 18618-970, Brazil
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Ebner LS, Lerche P, Bednarski RM, Hubbell JAE. Effect of dexmedetomidine, morphine-lidocaine-ketamine, and dexmedetomidine-morphine-lidocaine-ketamine constant rate infusions on the minimum alveolar concentration of isoflurane and bispectral index in dogs. Am J Vet Res 2013; 74:963-70. [DOI: 10.2460/ajvr.74.7.963] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Habler O, Voss B. [Perioperative management of Jehovah's Witness patients. Special consideration of religiously motivated refusal of allogeneic blood transfusion]. Anaesthesist 2010; 59:297-311. [PMID: 20379694 DOI: 10.1007/s00101-010-1701-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The religious organization of Jehovah's Witnesses numbers more than 7 million members worldwide, including 165,000 members in Germany. Although Jehovah's Witnesses strictly refuse the transfusion of allogeneic red blood cells, platelets and plasma, Jehovah's Witness patients may nevertheless benefit from modern therapeutic concepts including major surgical procedures without facing an excessive risk of death. The present review describes the perioperative management of surgical Jehovah's Witness patients aiming to prevent fatal anemia and coagulopathy. The cornerstones of this concept are 1) education of the patient about blood conservation techniques generally accepted by Jehovah's Witnesses, 2) preoperative optimization of the cardiopulmonary status and correction of preoperative anemia and coagulopathy, 3) perioperative collection of autologous blood, 4) minimization of perioperative blood loss and 5) utilization of the organism's natural anemia tolerance and its acute accentuation in the case of life-threatening anemia.
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Affiliation(s)
- O Habler
- Klinik für Anästhesiologie, Operative Intensivmedizin und Schmerztherapie, Krankenhaus Nordwest GmbH, Steinbacher Hohl 2-26, 60488 Frankfurt am Main.
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Oxygen transport characterization of a human model of progressive hemorrhage. Resuscitation 2010; 81:987-93. [PMID: 20418009 DOI: 10.1016/j.resuscitation.2010.03.027] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 03/18/2010] [Accepted: 03/24/2010] [Indexed: 11/23/2022]
Abstract
BACKGROUND Hemorrhage continues to be a leading cause of death from trauma sustained both in combat and in the civilian setting. New models of hemorrhage may add value in both improving our understanding of the physiologic responses to severe bleeding and as platforms to develop and test new monitoring and therapeutic techniques. We examined changes in oxygen transport produced by central volume redistribution in humans using lower body negative pressure (LBNP) as a potential mimetic of hemorrhage. METHODS AND RESULTS In 20 healthy volunteers, systemic oxygen delivery and oxygen consumption, skeletal muscle oxygenation and oral mucosa perfusion were measured over increasing levels of LBNP to the point of hemodynamic decompensation. With sequential reductions in central blood volume, progressive reductions in oxygen delivery and tissue oxygenation and perfusion parameters were noted, while no changes were observed in systemic oxygen uptake or markers of anaerobic metabolism in the blood (e.g., lactate, base excess). While blood pressure decreased and heart rate increased during LBNP, these changes occurred later than the reductions in tissue oxygenation and perfusion. CONCLUSIONS These findings indicate that LBNP induces changes in oxygen transport consistent with the compensatory phase of hemorrhage, but that a frank state of shock (delivery-dependent oxygen consumption) does not occur. LBNP may therefore serve as a model to better understand a variety of compensatory physiological changes that occur during the pre-shock phase of hemorrhage in conscious humans. As such, LBNP may be a useful platform from which to develop and test new monitoring capabilities for identifying the need for intervention during the early phases of hemorrhage to prevent a patient's progression to overt shock.
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Leone M, Blasco V, Martin C. Use of Mixed Venous Oxygen Saturation in ICU Patients. Intensive Care Med 2009. [DOI: 10.1007/978-0-387-77383-4_60] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Valente A, Sorrentino L, La Torre G, Draisci G. POST-TRANSFUSIONAL VARIATION IN URINARY OXYGEN TENSION IN SURGICAL PATIENTS. Clin Exp Pharmacol Physiol 2008; 35:1109-12. [DOI: 10.1111/j.1440-1681.2008.04949.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Literature about the effects of sedative drugs on the metabolic demand of critically ill patients is relatively old and of relatively poor quality. Most are experimental or observational studies. Level of evidence is therefore relatively low corresponding to "expert opinion". The effects of analgesics and hypnotics on tissue metabolic demand associated remain difficult to be adequately quantified. They are essentially related to a decreased neuro-humoral response to stress. This response involves principally the sympathetic system, which could be effectively blocked by most of the anesthetic agents. Other factors could participate to the observed reduction in tissue metabolic demand, as a decrease in spontaneous muscular activity, a reduction in work of breathing and/or a decrease in body temperature. The relative contribution of these different factors will depend on the clinical situation of the patient. Proper effects of anesthetic agents on cellular metabolism are limited as they can only decrease the functional component of this metabolism especially at the level of the heart and to some extent, at the level of the brain. Although the control of the sympathetic activity may be beneficial in critically ill patient, complete sympathetic blockade could be detrimental. Indeed, when oxygen transport to the tissues is acutely reduced, the sympathetic system plays an important role in the redistribution of blood flow according of local metabolic demand. The complete blunting of the neuro-humoral response to stress and therefore of the sympathetic system alters this physiological mechanism and results in a decrease in tissue oxygen extraction capabilities. An imbalance between tissue oxygen demand and delivery could appear with the development of cellular hypoxia. The institution of sedation in a critically ill patient requires careful evaluation of the sedation level using an appropriate scale. In patients in whom a reduction in metabolic demand is specifically requested, but also in patients with limited oxygen transport, the effects of sedative agents on the oxygen consumption-oxygen delivery relationship must also be monitored. The choice of the different agents to be administered will depend on the predefined objectives. As far as intravenous agents are concerned, there is no evidence than one association is more efficient in reducing patient's metabolic demand.
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Blasco V, Leone M, Textoris J, Visintini P, Albanèse J, Martin C. [Venous oximetry: physiology and therapeutic implications]. ACTA ACUST UNITED AC 2008; 27:74-82. [PMID: 18079088 DOI: 10.1016/j.annfar.2007.10.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Accepted: 10/09/2007] [Indexed: 01/08/2023]
Abstract
OBJECTIVES The aims of this review are to point out the determinants of oxygen saturation of the haemoglobin of mixed venous blood (SvO(2)), to specify the correlations existing between SvO(2) and central venous saturation in superior vena cava (ScvO(2)), to determine and finally to locate the current place of venous oximetry in clinical practice. DATA SOURCES A PubMed database research in English and French languages published until December 2006. The keywords were mixed venous blood oxygen saturation; oxygen consumption; oxygen delivery; oxygen extraction; tissue hypoxia; central venous oxygen saturation. DATA EXTRACTION Data in selected articles were reviewed, clinical and basic science research relevant information was extracted. DATA SYNTHESIS The SvO(2) reflects the peripheral extraction of oxygen (O(2)), O(2) delivery and consumption. Its value is related to four determinants: the O(2) consumption (VO(2)), cardiac flow (CF), haemoglobin level (Hb) and O(2) saturation of the haemoglobin of arterial blood (SaO(2)). ScvO(2) is more easily measurable than SvO(2). Under physiological conditions its value is 2 to 3% lower than that of SvO(2). In the critically ill patient, its value is 5% higher than that SvO(2). In most patients, changes in ScvO(2) values parallel those in SvO(2). The clinical interest of the monitoring of venous oximetry was underlined in cases of severe sepsis and septic shock, and during the perioperative period of major surgery. CONCLUSION The management of patients in critical states with therapeutic goals integrating the monitoring of venous oximetry may reduce the morbidity and mortality of patients undergoing major surgery or hospitalised in the intensive care unit.
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Affiliation(s)
- V Blasco
- Département d'anesthésie et de réanimation, faculté de médecine de Marseille, hôpital Nord, chemin des Bourrely, 13915 Marseille cedex 20, France.
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Lin GY, Robben JH, Murrell JC, Aspegrén J, McKusick BC, Hellebrekers LJ. Dexmedetomidine constant rate infusion for 24 hours during and after propofol or isoflurane anaesthesia in dogs. Vet Anaesth Analg 2008; 35:141-53. [DOI: 10.1111/j.1467-2995.2007.00365.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Habler O, Meier J, Pape A, Kertscho H, Zwissler B. [Tolerance to perioperative anemia. Mechanisms, influencing factors and limits]. Anaesthesist 2007; 55:1142-56. [PMID: 16826416 PMCID: PMC7095856 DOI: 10.1007/s00101-006-1055-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Die zu erwartende Kostensteigerung im Transfusionswesen (steigender Fremdblutbedarf bei gleichzeitig rückläufiger Spendebereitschaft, Behandlungspflicht transfusionsassoziierter Folgeerkrankungen) erhöht den sozioökonomischen Stellenwert der Entwicklung institutionsspezifischer Transfusionsprogramme. Ein wesentlicher Bestandteil hierbei ist – neben einer schonenden Operationstechnik und der konsequenten perioperativen Anwendung fremdblutsparender Maßnahmen – die Ausschöpfung der natürlicherweise vorhandenen „Anämietoleranz“ des menschlichen Organismus (Toleranz größerer Blutverluste durch Verlust von „verdünntem“ Blut, Hinauszögern des Transfusionsbeginns bis nach chirurgischer Blutstillung, Gewinnung von autologem Blut). In der vorliegenden Übersicht werden die Mechanismen, Einflussgrößen und Grenzen dieser natürlichen Anämietoleranz für den Gesamtorganismus und für einzelne Organsysteme zusammengefasst und die sich daraus ergebende Indikation zur Erythrozytentransfusion abgeleitet. Unter kontrollierten Bedingungen (Narkose, strikte Aufrechterhaltung von Normovolämie, komplette Muskelrelaxierung, Hyperoxämie, Hypothermie) werden von kardiopulmonal gesunden Individuen kurzzeitig auch extreme Grade der Verdünnungsanämie [Hämoglobin- (Hb-)Wert <3 g/dl (<1,86 mmol/l)] ohne Transfusion toleriert. In der klinischen Routine bleibt diese Situation – nicht zuletzt in Ermangelung eines adäquaten Monitorings – jedoch auf spezielle Sonderfälle beschränkt (z. B. unerwartete große Blutverluste bei Zeugen Jehovahs, unerwarteter Engpass bei der Bereitstellung von Fremdblut). Die derzeit geltenden Empfehlungen verschiedener Expertenkommissionen decken sich dahingehend, dass perioperativ (1) bis zu einer Hb-Konzentration von 10 g/dl (6,21 mmol/l) auch bei alten Patienten und Patienten mit kardiopulmonalen Begleiterkrankungen eine Transfusion von Erythrozyten in der Regel nicht notwendig ist und (2) eine Transfusion bei jungen, gesunden Patienten ohne kardiopulmonale Vorerkrankungen (einschließlich Schwangeren und Kindern) erst ab einer Hb-Konzentration von <6 g/dl (<3,72 mmol/l) notwendig wird. Auch beatmete Intensivpatienten mit Polytrauma und Sepsis scheinen nicht von einer Transfusion auf Hb-Konzentration >9 g/dl (>5,59 mmol/l) zu profitieren. Bei massiven Blutverlusten und diffuser Blutungsneigung scheint ein Hb von 10 g/dl (6,21 mmol/l) zur Stabilisierung der Blutgerinnung beizutragen.
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Affiliation(s)
- O Habler
- Klinik für Anästhesiologie, Operative Intensivmedizin und Schmerztherapie, Krankenhaus Nordwest GmbH, Steinbacher Hohl 2-26, 60488 Frankfurt am Main.
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Abstract
The goal of critical care medicine is to support organ function and maintain homeostasis until healing can occur. Sedation and analgesia may blunt the physiologic and psychologic sequelae of intensive care unit stress, and support homeostasis. Although a wide variety of agents have been used empirically, the recognition of analgesia, amnesia, and hypnosis as discrete elements comprising the sedated state has facilitated an individualized approach to therapy. Because intensive care unit patients are a highly heterogeneous population with varying levels of end-organ compromise, the development of specific, easily titratable, parenteral agents has made intensive care unit sedation safer. A trend toward refining dosage regimens in order to minimize the total dose of drug administered and to reduce the occurrence of residual sedation is driven by utilization and cost concerns. The capability for simple bedside electrophysiologic monitoring of the level of sedation is expected to improve the ability to provide optimal therapy.
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Affiliation(s)
- J E Szalados
- Department of Anesthesiology, Division of Critical Care Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
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Habler O, Meier J, Pape A, Kertscho H, Zwissler B. [Tolerance to perioperative anemia. Mechanisms, influencing factors and limits]. Urologe A 2007; 46:W543-56; quiz W557-8. [PMID: 17429601 PMCID: PMC7095997 DOI: 10.1007/s00120-007-1344-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Die zu erwartende Kostensteigerung im Transfusionswesen erhöht den sozioökonomischen Stellenwert der Entwicklung institutionsspezifischer Transfusionsprogramme. Ein wesentlicher Bestandteil hierbei ist – neben einer schonenden Operationstechnik und der konsequenten perioperativen Anwendung fremdblutsparender Maßnahmen – die Ausschöpfung der natürlichen „Anämietoleranz“ des menschlichen Organismus. Im vorliegenden Beitrag werden die Mechanismen, Einflussgrößen und Grenzen dieser Anämietoleranz für den Gesamtorganismus und für einzelne Organsysteme zusammengefasst und die sich daraus ergebende Indikation zur Erythrozytentransfusion abgeleitet. Die derzeit geltenden Empfehlungen decken sich dahingehend, dass bis zu einer Hämoglobinkonzentration von 10 g/dl (6,21 mmol/l) auch bei alten Patienten oder kardiopulmonalen Begleiterkrankungen eine perioperative Transfusion in der Regel nicht notwendig ist und bei jungen, gesunden Patienten ohne kardiopulmonale Vorerkrankungen (einschließlich Schwangeren und Kindern) erst ab <6 g/dl (<3,72 mmol/l) notwendig wird. Auch beatmete Intensivpatienten mit Polytrauma und Sepsis scheinen nicht von einer Transfusion auf eine Hämoglobinkonzentration >9 g/dl (>5,59 mmol/l) zu profitieren. Bei massiven Blutverlusten und diffuser Blutungsneigung scheint ein Wert von 10 g/dl (6,21 mmol/l) zur Stabilisierung der Blutgerinnung beizutragen.
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Affiliation(s)
- O Habler
- Klinik für Anästhesiologie, Operative Intensivmedizin und Schmerztherapie, Krankenhaus Nordwest GmbH, Steinbacher Hohl 2-26, 60488 Frankfurt a.M.
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Haskins SC. Comparative cardiovascular and pulmonary effects of sedatives and anesthetic agents and anesthetic drug selection for the trauma patient. J Vet Emerg Crit Care (San Antonio) 2006. [DOI: 10.1111/j.1476-4431.2006.00188.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Durongphongtorn S, McDonell WN, Kerr CL, Neto FJT, Mirakhur KK. Comparison of hemodynamic, clinicopathologic, and gastrointestinal motility effects and recovery characteristics of anesthesia with isoflurane and halothane in horses undergoing arthroscopic surgery. Am J Vet Res 2006; 67:32-42. [PMID: 16426209 DOI: 10.2460/ajvr.67.1.32] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare hemodynamic, clinicopathologic, and gastrointestinal motility effects and recovery characteristics of halothane and isoflurane in horses undergoing arthroscopic surgery. ANIMALS 8 healthy adult horses. PROCEDURE Anesthesia was maintained with isoflurane or halothane (crossover study). At 6 intervals during anesthesia and surgery, cardiopulmonary variables and related derived values were recorded. Recovery from anesthesia was assessed; gastrointestinal tract motility was subjectively monitored for 72 hours after anesthesia. Horses were administered chromium, and fecal chromium concentration was used to assess intestinal transit time. Venous blood samples were collected for clinicopathologic analyses before and 2, 24, and 48 hours after anesthesia. RESULTS Compared with halothane-anesthetized horses, cardiac index, oxygen delivery, and heart rate were higher and systemic vascular resistance was lower in isoflurane-anesthetized horses. Mean arterial blood pressure and the dobutamine dose required to maintain blood pressure were similar for both treatments. Duration and quality of recovery from anesthesia did not differ between treatments, although the recovery periods were somewhat shorter with isoflurane. After isoflurane anesthesia, gastrointestinal motility normalized earlier and intestinal transit time of chromium was shorter than that detected after halothane anesthesia. Compared with isoflurane, halothane was associated with increases in serum aspartate transaminase and glutamate dehydrogenase activities, but there were no other important differences in clinicopathologic variables between treatments. CONCLUSIONS AND CLINICAL RELEVANCE Compared with halothane, isoflurane appears to be associated with better hemodynamic stability during anesthesia, less hepatic and muscle damage, and more rapid return of normal intestinal motility after anesthesia in horses undergoing arthroscopic procedures.
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Affiliation(s)
- Sumit Durongphongtorn
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
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21
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Van der Linden PJ, De Hert SG, Belisle S, Sahar G, Deltell A, Bekkrar Y, Blauwaert M, Vincent JL. Critical oxygen delivery during cardiopulmonary bypass in dogs. Eur J Anaesthesiol 2006; 23:10-6. [PMID: 16390559 DOI: 10.1017/s0265021505001699] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/18/2005] [Indexed: 11/05/2022]
Abstract
BACKGROUND AND OBJECTIVE To determine the minimal oxygen delivery and pump flow that can maintain systemic oxygen uptake during normothermic (37 degrees C) pulsatile and non-pulsatile cardiopulmonary bypass in dogs. METHODS Eighteen anaesthetized dogs were randomly assigned to receive either non-pulsatile (Group C; n = 9) or pulsatile bypass flow (Group P; n = 9). Oxygen delivery was reduced by a progressive decrease in pump flow, while arterial oxygen content was maintained constant. In each animal, critical oxygen delivery was determined from plots of oxygen uptake vs. oxygen delivery and from plots of blood lactate vs. oxygen delivery using a least sum of squares technique. Critical pump flow was determined from plots of lactate vs. pump flow. RESULTS At the critical point, oxygen delivery obtained from oxygen uptake was 7.7 +/- 1.1 mL min(-1) kg(-1) in Group C and 6.8 +/- 1.8 mL min(-1) kg(-1) in Group P (n.s.). These values were similar to those obtained from lactate measurements (Group C: 7.8 +/- 1.6 mL min(-1) kg(-1); Group P: 7.6 +/- 2.0 mL min(-1) kg(-1)). Critical pump flows determined from lactate measurements were 55.6 +/- 13.8 mL min(-1) kg(-1) in Group C and 60.8 +/- 13.9 mL min(-1) kg(-1) in Group P (n.s.). CONCLUSIONS Oxygen delivery values greater than 7-8 mL min(-1) kg(-1) were required to maintain oxygen uptake during normothermic cardiopulmonary bypass with either pulsatile or non-pulsatile blood flow. Elevation of blood lactate levels during bypass helps to identify inadequate tissue oxygen delivery related to insufficient pump flow.
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Affiliation(s)
- P J Van der Linden
- Charleroi University Hospital, Department of Cardiac Anaesthesia (now CHU-Brugmann, Department of Anaesthesiology, Brussels), Charleroi, Belgium
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22
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Torres Filho IP, Spiess BD, Pittman RN, Barbee RW, Ward KR. Experimental analysis of critical oxygen delivery. Am J Physiol Heart Circ Physiol 2005; 288:H1071-9. [DOI: 10.1152/ajpheart.00884.2004] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Systemic variables were evaluated with respect to O2 delivery to test the hypothesis that critical O2 delivery and critical Hb can be estimated by multiple variables collected simultaneously. Rats were subjected to transfusion with either fresh or stored blood and then subjected to stepwise isovolemic hemodilution. Critical levels were measured by the dual-regression method from plots of systemic variables against O2 delivery and Hb. Delivery was calculated from cardiac index and arterial O2 content. We found that 1) after hemodilution, O2 delivery changed in a nonlinear relationship with Hb; 2) critical delivery calculated using 30 different systemic variables was not statistically different from each other; 3) critical delivery and critical Hb were correlated but were not different between animals receiving fresh or stored blood; and 4) similar critical levels were found using a single variable from several animals and using several variables from the same subject. The best variables to estimate critical delivery were lactate, bicarbonate, base excess, O2 extraction ratio, expired CO2, pulse pressure, cardiac index, and systolic pressure. The data suggest that a multivariable analysis of critical delivery may help determine the physiological oxygenation boundary at the whole body level. This may assist in finding therapeutic triggers on an individual basis using systemic markers of the transition from aerobic to anaerobic metabolism.
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23
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Vincent JL, De Backer D. Oxygen transport-the oxygen delivery controversy. Intensive Care Med 2004; 30:1990-6. [PMID: 15258731 DOI: 10.1007/s00134-004-2384-4] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2003] [Accepted: 06/24/2004] [Indexed: 12/22/2022]
Affiliation(s)
- Jean-Louis Vincent
- Department of Intensive Care, Erasme University Hospital, Free University of Brussels, Route de Lennik 808, 1070 Brussels, Belgium.
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24
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Jamnicki M, Kocian R, van der Linden P, Zaugg M, Spahn DR. Acute normovolemic hemodilution: physiology, limitations, and clinical use. J Cardiothorac Vasc Anesth 2003; 17:747-54. [PMID: 14689419 DOI: 10.1053/j.jvca.2003.09.018] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Marina Jamnicki
- Institute of Anesthesiology, University Hospital Zurich, Zurich, Switzerland
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25
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Smithline HA, Ward KR, Chiulli DA, Blake HC, Rivers EP. Whole body oxygen consumption and critical oxygen delivery in response to prolonged and severe carbon monoxide poisoning. Resuscitation 2003; 56:97-104. [PMID: 12505745 DOI: 10.1016/s0300-9572(02)00272-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Carbon monoxide (CO) poisoning remains the leading cause of death by poisoning in the world. One of the major proposed mechanisms for CO toxicity is the binding of CO to cytochrome oxidase and interference with cellular oxygen utilization but evidence for this is inconclusive. AIM OF STUDY This study examined the effects of prolonged CO exposure on the dynamics of whole body oxygen consumption (VO(2)) and oxygen delivery (DO(2)) in an attempt to observe if CO exposure results in a defect of oxygen utilization defect as determined by a reduction in VO(2) during the course of poisoning prior to reaching the point where VO(2) is directly dependent on DO(2). This critical level of DO(2) (DO(2)crit) produced by CO poisoning was compared to historical values produced by other insults, which decrease global body DO(2). METHODS Five small dogs were ventilated for 2 h with 0.25% CO and room air followed by 0.5% CO until death. Cardiac index (Q), DO(2), VO(2), oxygen extraction ratio (OER), and systemic lactate were measured every 15 min until death. RESULTS Carboxyhemoglobin (COHb) levels increased linearly over 2.5 h to values above 80% until death. VO(2) remained constant and not significantly different from baseline below a COHb of 80%. At COHb levels above 80%, VO(2) precipitously dropped. Similarly lactate levels were not significantly elevated from baseline until VO(2) dropped. DO(2) decreased by 78% (from 23+/-6 ml/kg/min to 5+/-4 ml/kg/min) over time despite an increase in Q by 58% until levels of COHb were above 80%. OER increased from 19+/-5% to 50+/-11% until death. The calculated DO(2)crit was 10.7+/-4 ml/min/kg, which is not significantly different from values ranging from 7 to 13 ml/min/kg reported in the literature due to other insults, which reduce DO(2). CONCLUSION In this canine model of prolonged CO exposure, no gradual reduction in VO(2) or increase in systemic lactate prior to reaching DO(2)crit was noted. In addition, CO exposure does not appear to change the DO(2)crit. The combination of these findings does not support the theory that CO produces a whole body intracellular defect in oxygen utilization.
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Affiliation(s)
- Howard A Smithline
- Baystate Medical Center, Department of Emergency Medicine, Baystate, MA, USA
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26
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Ganushchak YM, Maessen JG, de Jong DS. The oxygen debt during routine cardiac surgery: illusion or reality? Perfusion 2002; 17:167-73. [PMID: 12017383 DOI: 10.1191/0267659102pf561oa] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Patients undergoing cardiac surgery with the use of cardiopulmonary bypass (CPB) are often thought to have tissue hypoxia and intraoperative oxygen debt accumulation despite the lack of sufficient data to support this assumption. METHODS AND RESULTS Oxygen uptake and related parameters, including the plasma lactate and pyruvate concentrations, were studied during the perioperative period in a group of 15 consecutive patients who underwent coronary artery bypass graft surgery. The actual oxygen uptake (VO2) and delivery (DO2) were compared with the individual expected (computed) oxygen transport values. The mean values of DO2 and VO2 were in the range of the expected values. Our results demonstrate a leading role for body temperature in perioperative changes of oxygen consumption rate (r2=0.65, p<0.001). Plasma lactate and pyruvate did not exceed the physiological range in any patient. However, with initiation of CPB, the lactate to pyruvate (LA/PVA) ratio increased (from 9.87 +/- 2.43 at T1 to 12.08 +/- 1.51 at T2, p<0.05). The mean value of the LA/ PVA ratio was elevated during surgery. Later, upon lowering of the plasma lactate concentration in the postoperative period, the LA/PVA ratio decreased to normal values. Without any other evidence of hypoxia, this increase in the LA/PVA ratio could be explained by washout of lactate from previously hypoperfused tissues and intraoperative decrease of lactate clearance. CONCLUSION Systemic oxygenation was not impaired during CPB, or during 18 h after surgery in the studied group of patients.
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Affiliation(s)
- Y M Ganushchak
- Department of Extra Corporeal Circulation, University Hospital Maastricht, The Netherlands.
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27
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Van der Linden P, De Hert S, Bélisle S, De Groote F, Mathieu N, d'Eugenio S, Julien V, Huynh C, Mélot C. Comparative effects of red blood cell transfusion and increasing blood flow on tissue oxygenation in oxygen supply-dependent conditions. Am J Respir Crit Care Med 2001; 163:1605-8. [PMID: 11401881 DOI: 10.1164/ajrccm.163.7.2001003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Red blood cell (RBC) transfusion is usually administered to improve oxygen delivery (DO(2)) in order to sustain tissue oxygen demand. However, this practice is not supported by firm clinical or experimental data. Using a randomized two-period crossover design, this study compared the efficacy of "fresh" RBC transfusion and increased blood flow to restore tissue oxygenation in oxygen supply-dependent conditions. In 12 ketamine-anesthetized mongrel dogs submitted to nonpulsatile normothermic cardiopulmonary bypass, DO(2) was reduced by a progressive decrease in pump flow. DO(2) dependency was defined as an O(2) uptake (V O(2)) decrease by more than 15% from baseline value. Then, intervention consisted of a 40% increase in DO(2) obtained either by transfusion of "fresh" dog's RBC (stored < 3 d) or by increase in pump flow. Animals received both interventions sequentially in a random order, while O(2) saturation was maintained constant. In O(2) supply-dependent conditions, rising pump flow from 1.6 +/- 0.4 to 2.7 +/- 0.7 L/ min increased DO(2) from 5.4 +/- 1.1 to 9.0 +/- 1.3 ml/kg/min (p < 0.01) and V O(2) from 3.5 +/- 0.4 to 4.1 +/- 0.5 ml/kg/min (p = 0.02). "Fresh" RBC transfusion, which increased the hemoglobin concentration from 6.4 +/- 0.9 to 11.1 +/- 1.3 g/dl, increased DO(2) from 5.4 +/- 1.2 to 9.0 +/- 1.4 ml/kg/min (p < 0.01) and V O(2) from 3.6 +/- 0.4 to 4.1 +/- 0.5 ml/kg/min (p = 0.02). There was no difference in V O(2) resulting from both interventions. In oxygen supply-dependent conditions, "fresh" RBC transfusion and increased blood flow are equally effective in restoring tissue oxygenation.
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Affiliation(s)
- P Van der Linden
- Department of Experimental Anesthesia, Erasme University Hospital, Brussels, Belgium.
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28
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Van der Linden P, Schmartz D, Gilbart E, Engelman E, Vincent JL. Effects of propofol, etomidate, and pentobarbital on critical oxygen delivery. Crit Care Med 2000; 28:2492-9. [PMID: 10921584 DOI: 10.1097/00003246-200007000-00051] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To test the hypothesis that propofol, etomidate, and pentobarbital increase critical oxygen delivery in a dose-dependent manner during progressive hemorrhage. DESIGN Prospective, randomized laboratory investigation. SETTING University laboratory. SUBJECTS A total of 40 anesthetized, paralyzed, and mechanically ventilated dogs weighing 29.2+/-4.6 kg. INTERVENTIONS Dogs were randomly assigned to be anesthetized with propofol (n = 13), etomidate (n = 13), or pentobarbital (n = 14) at either low or high dosages. At 30 mins after splenectomy, the dogs underwent progressive hemorrhage by successive withdrawals of 3-5 mL/kg arterial blood. MEASUREMENTS AND MAIN RESULTS At each step of hemorrhage, oxygen consumption and oxygen delivery were determined. Oxygen consumption was obtained from expired gas analysis, and oxygen delivery was determined from thermodilution cardiac output and calculated arterial oxygen content. In each animal, critical oxygen delivery and critical oxygen consumption were obtained from a plot of oxygen consumption vs. oxygen delivery as the point of intersection of the two best-fit regression lines determined by a least sum of squares method. Critical oxygen extraction was obtained by dividing critical oxygen consumption by critical oxygen delivery. In the three groups, animals receiving the higher anesthetic infusion had a significantly higher critical oxygen delivery (propofol: 10.5+/-0.8 vs. 13.9+/-2.5 mL/min/m2, p < .05; etomidate: 10.1+/-0.7 vs. 13.4+/-3.0 mL/min/m2, p < .05; pentobarbital: 7.8+/-1.0 vs. 12.3+/-2.5 mL/min/m2, p < .01) attributable to a lower critical oxygen extraction ratio (propofol: 41.1+/-6.4% vs. 54.2+/-2.5%, p < .01; etomidate: 42.7+/-10.2% vs. 60.6+/-7.1%, p < .01; pentobarbital: 42.2+/-7.2% vs. 64.3+/-8.8%, p < .01). CONCLUSIONS This study indicates that propofol, etomidate, and pentobarbital increased critical oxygen delivery in a dose-dependent manner. This effect was mainly related to a decrease in tissue oxygen extraction capabilities.
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Affiliation(s)
- P Van der Linden
- Department of Cardiac Anesthesia, Centre Hospitalier Universitaire, Charleroi, Belgium
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29
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Alfaro V, Pesquero J, Palacios L. Acid-base disturbance during hemorrhage in rats: significant role of strong inorganic ions. J Appl Physiol (1985) 1999; 86:1617-25. [PMID: 10233126 DOI: 10.1152/jappl.1999.86.5.1617] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The present study tests the hypothesis that changes in the strong inorganic ion concentrations contribute significantly to the acid-base disturbance that develops during hemorrhage in the arterial plasma of rats in addition to lactate concentration ([Lac-]) increase. The physicochemical origins for this acid-base disorder were studied during acute, graded hemorrhage (10, 20, and 30% loss of blood volume) in three groups of rats: conscious, anesthetized with ketamine, and anesthetized with urethan. The results support the hypothesis examined: strong-ion difference (SID) decreased in the arterial plasma of all groups studied because of an early imbalance in the main strong inorganic ions during initial hemorrhagic phase. Moreover, changes in plasma [Lac-] contributed to SID decrease in a later hemorrhagic phase (after 10% hemorrhage in urethan-anesthetized, after 20% hemorrhage in ketamine-anesthetized, and after 30% hemorrhage in conscious group). Inorganic ion changes were due to both dilution of the vascular compartment and ion exchange with extravascular space and red blood cells, as compensation for blood volume depletion and hypocapnia. Nevertheless, anesthetized rats were less able than conscious rats to preserve normal arterial pH during hemorrhage, mainly because of an impaired peripheral tissue condition and incomplete ventilatory compensation.
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Affiliation(s)
- V Alfaro
- Departamento de Fisiología, Facultad de Biología, Universidad de Barcelona, E-08028 Barcelona, Spain.
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30
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Licker M, Schweizer A, Hohn L, Morel DR. Haemodynamic and metabolic changes induced by repeated episodes of hypoxia in pigs. Acta Anaesthesiol Scand 1998; 42:957-65. [PMID: 9773141 DOI: 10.1111/j.1399-6576.1998.tb05356.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Repeated hypoxia and surgical trauma trigger a potent neuroendocrine response and their association is thought to play a pivotal role in the pathogenesis of multi-organ dysfunction. We investigated the cardiovascular and metabolic responses to repeated acute hypoxia in anaesthetised and surgically instrumented pigs. METHODS Under ketamine-midazolam anaesthesia, 15 pigs were surgically instrumented for measurements of cardiac output, vascular pressures and organ blood flows. Lactate production and O2 uptake were determined in the brain, liver, kidney and intestine. Ten animals were subjected to two 12-min periods of ventilatory hypoxia (FIO2 = 7%) followed by re-oxygenation and 5 animals underwent 120-min normoxic ventilation (Control group). RESULTS Both hypoxic challenges produced a comparable release of catecholamines that was associated with increased cardiac output and redistribution of blood flow away from the intestinal and renal areas towards the brain and the liver; O2 uptake was markedly reduced in the intestine (-56 +/- 10%, P < 0.05) and least affected in the brain and the kidney (-19 +/- 12% and -23 +/- 21%, respectively). During the second hypoxic test, lethal cardiovascular depression occurred in 5 animals; these non-survivors demonstrated impaired hyperdynamic response and incomplete recovery of intestinal O2 uptake during the first hypoxia/reoxygenation test. In the Control group, normoxic ventilation was not associated with significant haemodynamic and metabolic changes. CONCLUSION Intraoperative hypoxia causes marked heterogeneity in organ blood flow and metabolism. The inability to develop a hyperdynamic cardiovascular response during a first hypoxic event, as well as a persistent intestinal O2 debt following re-oxygenation, predict the occurrence of death during the second hypoxic insult.
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Affiliation(s)
- M Licker
- Divisions of Anaesthesiological Investigations, University Hospital of Geneva, Switzerland
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31
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Cavaliere F. A nomogram to evaluate the arterial mixed venous oxygen saturation difference during cardiopulmonary bypass. Perfusion 1998; 13:45-51. [PMID: 9500248 DOI: 10.1177/026765919801300106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A nomogram providing the arterial mixed venous haemoglobin saturation difference (S(a-v)O2) corresponding to normal oxygen consumption (VO2) during cardiopulmonary bypass (CPB) was produced. Normal VO2 during CPB (95.8 +/- 20.1 ml/min/m2 at 37 degrees C) was obtained from the literature. The nomogram computes the S(a-v)O2 from the body surface, pump flow, blood haemoglobin and patient temperature; a table is also presented which supplies the S(a-v)O2 ranges corresponding to VO2 mean +/-1 and +/-2SD. The nomogram was tested on 10 subjects undergoing CPB for myocardial revascularization. S(a-v)O2 was determined by arterial and mixed venous blood oximetry 5, 20, and 35 min after the start of CPB. The measured S(a-v)O2 was 27.1 +/- 7.2% while S(a-v)O2 obtained from the nomogram was 24.9 +/- 4.0%, the difference was not statistically significant. Eighteen values (60%) were within the range corresponding to VO2 mean +/-1SD. One value was lower than the S(a-v)O2 value corresponding to VO2 mean - 2SD and was associated with the lowest value of blood haemoglobin. Two values were higher than the S(a-v)O2 value corresponding to VO2 mean + 2SD and were associated with inadequate muscle relaxation. By comparing measured S(a-v)O2 values with those obtained by the nomogram and the table, anaesthesiologists and perfusionists can easily detect patients presenting abnormally low or high VO2 values.
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Affiliation(s)
- F Cavaliere
- Institute of Anaesthesiology and Intensive Care, Catholic University of the Sacred Heart, Rome, Italy
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Sielenkämper AW, Chin-Yee IH, Martin CM, Sibbald WJ. Diaspirin crosslinked hemoglobin improves systemic oxygen uptake in oxygen supply-dependent septic rats. Am J Respir Crit Care Med 1997; 156:1066-72. [PMID: 9351604 DOI: 10.1164/ajrccm.156.4.9609097] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Diaspirin crosslinked hemoglobin (DCLHb) is a cell-free hemoglobin derived from human erythrocytes. DCLHb has been shown to improve blood flow to vital organs in healthy and septic animals. In this study, we determined the efficacy of DCLHb by comparing its effect on systemic O2 uptake to freshly stored and aged red blood cells (RBCs) in septic rats. Twenty-four hours after induction of sepsis by cecal ligation and perforation, O2 supply dependency was created by isovolemic hemodilution with rat plasma. In O2 supply dependency, rats were randomized to receive an exchange transfusion of 7.5 ml "fresh" RBCs (stored < 6 d; Hct: 70%), "fresh" diluted RBCs (stored < 6 d; Hct: 30%), "old" RBCs (stored 28 to 35 d; Hct: 70%), or DCLHb (Hb: 100 g/L). We found, that survival following O2 supply dependency and transfusion with old RBCs was poor (33% versus 91.7% in the other groups; p < 0.01), precluding further analysis of post-transfusion data from this group. Systemic O2 uptake increased in all remaining groups (p < 0.001), while systemic O2 delivery increased with "fresh" RBCs (p < 0.0001) and "fresh" diluted RBCs (p < 0.05) but not with DCLHb. Systemic O2 extraction increased with DCLHb as compared to baseline (p < 0.05) and to the other groups (p < 0.0001). Improved tissue oxygenation was associated with an increase in blood pressure and a fall in arterial lactate in all groups. We conclude that transfusion of DCLHb or "fresh" RBCs was efficacious at increasing systemic O2 uptake in O2 supply-dependent, septic rats.
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Affiliation(s)
- A W Sielenkämper
- A.C. Burton Vascular Biology Laboratory, Victoria Hospital Research Institute and University of Western Ontario, London, Canada
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33
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Fitzgerald RD, Martin CM, Dietz GE, Doig GS, Potter RF, Sibbald WJ. Transfusing red blood cells stored in citrate phosphate dextrose adenine-1 for 28 days fails to improve tissue oxygenation in rats. Crit Care Med 1997; 25:726-32. [PMID: 9187588 DOI: 10.1097/00003246-199705000-00004] [Citation(s) in RCA: 192] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To determine whether the time that red blood cells are stored in citrate phosphate dextrose adenine-1 solution before transfusion alters the ability to improve tissue oxygenation. DESIGN Prospective, randomized, controlled study. SETTING University research institute laboratory. SUBJECTS Male Sprague-Dawley rats (350 to 450 g). INTERVENTIONS Twenty-four hours after randomization to sham laparotomy (n = 21) or cecal ligation and perforation (n = 16)1 supply-dependency of systemic oxygen uptake (VO2) was induced in rats by isovolemic hemodilution. Rats were then re-randomized to receive either rat red blood cells stored in citrate phosphate dextrose adenine-1 for 3 days ("fresh" n = 17) or rat red blood cells stored in citrate phosphate dextrose adenine-1 for 28 days ("old" n = 20). MEASUREMENTS AND MAIN RESULTS Changes in systemic VO2 were measured for 90 mins to determine the efficiacy of the treatment. Statistical analysis included a fully factorial repeated-measures, generalized linear model. No significant interaction was found between cecal ligation and perforation or sham animals and transfusion with fresh or old red blood cells. However, comparing the combined groups of animals receiving either fresh or old red blood cells, we found that after the transfusion of old red blood cells, systemic VO2 was not significantly improved (after hemodilution 1.68 +/- 0.27 mL/100 g/min, after transfusion 1.86 +/- 0.17 mL/100 g/min; p > .05). In contrast, transfusion with fresh red blood cells acutely increased systemic VO2 (after hemodilution 1.62 +/- 0.06 mL/100 g/min, after transfusion 2.10 +/- 0.09 mL/100 g/min; p = .049). CONCLUSION Storage of rat red blood cells for 28 days in citrate phosphate dextrose adenine-1 impaired their ability to improve tissue oxygenation when transfused into either control or septic rats placed into supply dependency of systemic VO2.
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Affiliation(s)
- R D Fitzgerald
- A. C. Burton Vascular Biology Laboratory, Victoria Hospital Research Institute, University of Western Ontario, London, Canada
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Sowade O, Gross J, Sowade B, Warnke H, Franke W, Messinger D, Scigalla P, Lun A, Glatzel E. Evaluation of oxygen availability with oxygen status algorithm in patients undergoing open heart surgery treated with epoetin beta. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 1997; 129:97-105. [PMID: 9011596 DOI: 10.1016/s0022-2143(97)90166-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We evaluated in a double-blind randomized study the effect of epoetin beta (recombinant human erythropoietin) therapy on oxygen status in patients undergoing cardiac surgery who were contraindicated for autologous blood donation. All 76 patients enrolled in this study were randomized to the two treatment groups (5 x 500 U epoetin beta or placebo/kg body weight intravenously over a 14-day period before surgery) and received 300 mg Fe2+ per day orally before surgery. Before and after surgery the lactate level and the following parameters according to the oxygen status algorithm by Siggaard-Andersen were evaluated: arterial oxygen tension (PaO2), effective hemoglobin concentration (ceHb), arterial oxygen saturation (SaO2), oxygen half saturation tension (p50), red cell 2.3 diphosphoglycerate (2.3 DPG), arterial total oxygen concentration (ctO2), concentration of extractable oxygen (cx), and oxygen compensation factor (Qx). Therapy with epoetin beta led to increases in ceHb, PaO2, ctO2, and cx and to a decrease in Qx before surgery (p < 0.05 for PaO2, p < 0.0001 for the other parameters vs placebo). The cx in patients who received epoetin beta rose by approximately 20%, thus indicating a considerable improvement in O2 delivery. In patients receiving placebo the hemoximetric parameters remained outside the normal limits at all times after surgery, but in the epoetin beta group PaO2, ctO2, cx, and Qx returned almost to their baseline values by the second or fifth postoperative day, even though the frequency of transfusions was significantly higher in the placebo group. Whereas p50 and 2.3 DPG fell in the placebo group after surgery, these two parameters were significantly higher in the epoetin beta group and led to a further increase in cx (from 24% to 38%) versus the placebo group as a result of the right shift in the hemoglobin O2-binding curve. The postoperative incidence and severity of lactic acidosis were higher in the placebo group. Preoperative epoetin beta therapy is a safe way of providing increased extractable O2 (by 24% to 38%) and decreasing the risk of lactic acidosis after surgery. This therapy has a more favorable effect on the O2 binding curve than the transfusion of erythrocyte concentrate and enhances the effect of epoetin beta therapy on the postoperative oxygen status.
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Affiliation(s)
- O Sowade
- Clinic of Cardiac Surgery, Institute of Pathological and Clinical Biochemistry, Medical Faculty (Charite), Humboldt University Berlin, Germany
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Vincent JL, van der Linden P. Physiology of VO2/DO2. UPDATE IN INTENSIVE CARE AND EMERGENCY MEDICINE 1997. [DOI: 10.1007/978-3-642-60696-0_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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36
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Relation between systemic oxygen uptake and tissue oxygen extraction following cardiac surgery. Eur J Anaesthesiol 1996. [DOI: 10.1097/00003643-199611000-00004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Bélisle S, Van der Linden P, Hardy JF. Correction of anaemia: the time has come to evaluate tolerance for red cell depletion. Can J Anaesth 1996; 43:647-52. [PMID: 8807167 DOI: 10.1007/bf03017945] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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Vincent JL, De Backer D. Oxygen uptake/oxygen supply dependency: fact or fiction? ACTA ANAESTHESIOLOGICA SCANDINAVICA. SUPPLEMENTUM 1995; 107:229-37. [PMID: 8599284 DOI: 10.1111/j.1399-6576.1995.tb04364.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
More than a decade ago, observations of co-variance between VO2 and DO2 led to the identification of a condition known as pathological O2 supply dependency. This condition was subsequently observed in critically ill patients with sepsis and acute circulatory failure. More recently, other authors have challenged the existence of this condition, often citing methodologic problems or mathematical coupling to account for spurious observations in the earlier studies. Here, we review the evidence for and against pathological O2 supply dependency. We find that many of the arguments have some validity but only in specific circumstances. We conclude, therefore, that pathological O2 supply dependency is a hallmark of acute circulatory failure and that an effective therapeutic approach should be based on an evaluation of organ system function in each individual case. Parameters such as blood lactate, pHi and veno-arterial PCO2 may be useful in this respect.
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Affiliation(s)
- J L Vincent
- Department of Intensive Care, Erasme University Hospital, Free University of Brussels, Belgium
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Kjellgren P, Gupta A, Sjöberg F. Volume replacement during cardiac surgery-influence on microcirculation. Acta Anaesthesiol Scand 1995; 39:709-10. [PMID: 7572025 DOI: 10.1111/j.1399-6576.1995.tb04152.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Abstract
Intravenous ketamine anaesthesia has been used by the British army in the field for many years. A recognised problem has been the unpredictable recovery profile this produces. We anaesthetised 28 ASA 1 patients using a standard British military technique. At termination of the anaesthetic, half of the patients were given a physostigmine/glycopyrronium mixture and half were given the equivalent volume of saline 0.9%. There was a significant difference between the two groups with regard to recovery times (p < 0.001). There was no significant difference with regard to other variables. In trauma anaesthesia the improved recovery profile from the use of physostigmine following ketamine anaesthesia may lead to earlier evacuation of the patient.
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Affiliation(s)
- C Hamilton-Davies
- Department of Anaesthesia, Cambridge Military Hospital, Aldershot, Hampshire
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Van der Linden P, Rausin I, Deltell A, Bekrar Y, Gilbart E, Bakker J, Vincent JL. Detection of Tissue Hypoxia by Arteriovenous Gradient for PCO2 and pH in Anesthetized Dogs During Progressive Hemorrhage. Anesth Analg 1995. [DOI: 10.1213/00000539-199502000-00012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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43
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Van der Linden P, Rausin I, Deltell A, Bekrar Y, Gilbart E, Bakker J, Vincent JL. Detection of tissue hypoxia by arteriovenous gradient for PCO2 and pH in anesthetized dogs during progressive hemorrhage. Anesth Analg 1995; 80:269-75. [PMID: 7818112 DOI: 10.1097/00000539-199502000-00012] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The present study tested the hypothesis that, during acute bleeding, the development of tissue hypoxia might be reflected by an abrupt widening in arteriovenous gradient for PCO2 (AV PCO2) and for pH (AV pH) as accurately as by an increase in blood lactate levels. Twenty-four anesthetized (isoflurane 1.4% end-tidal), paralyzed, and mechanically ventilated dogs submitted to progressive hemorrhage were studied. Oxygen uptake (VO2) was derived from expired gas analysis and oxygen delivery (DO2) was calculated by the product of the thermodilution cardiac index and the arterial O2 content. During the first part of the protocol, VO2 remained stable as the progressive reduction in DO2 was associated with a corresponding increase in O2 extraction (O2ER). Blood lactate increased slightly but not significantly. AV PCO2 and AV pH increased significantly, essentially related to venous respiratory acidosis. The critical value of DO2 below which VO2 decreased was 8.95 +/- 1.60 mL.min-1.kg-1. Below this value, there was a marked increase in blood lactate and an abrupt widening in AV PCO2 and AV pH gradients. The critical value of DO2 obtained from blood lactate, AV PCO2 and AV pH were similar to those obtained from VO2 (8.60 +/- 1.12; 8.73 +/- 1.40; 8.78 +/- 1.37, respectively; P = not significant). A significant correlation was found, during the hemorrhage protocol, between blood lactate and AV PCO2 (r = 0.84; P < 0.001) or AV pH (r = 0.78; P < 0.001). Therefore, AV PCO2 and AV pH represent simple but reliable indicators of tissue hypoxia during hemorrhagic shock.
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Affiliation(s)
- P Van der Linden
- Department of Anesthesiology, Erasme University Hospital, Brussels, Belgium
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Annat G, Janvier G. [Relations between body oxygen requirement, transport, consumption and tissue extraction]. ANNALES FRANCAISES D'ANESTHESIE ET DE REANIMATION 1995; 14 Suppl 1:1-2. [PMID: 7486311 DOI: 10.1016/s0750-7658(05)81797-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Affiliation(s)
- G Annat
- Laboratoire de Physiologie, Faculté de Médecine de Lyon Grange-Blanche, Lyon
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45
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Janvier G, Annat G. [Are there any limits to hemodilution?]. ANNALES FRANCAISES D'ANESTHESIE ET DE REANIMATION 1995; 14 Suppl 1:9-20. [PMID: 7486322 DOI: 10.1016/s0750-7658(05)81799-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- G Janvier
- Département d'Anesthésie-Réanimation II, Hôpital Cardiologique, Pessac
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46
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Silance PG, Simon C, Vincent JL. The relation between cardiac index and oxygen extraction in acutely ill patients. Chest 1994; 105:1190-7. [PMID: 8162748 DOI: 10.1378/chest.105.4.1190] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The relation between cardiac index and oxygen extraction (O2ER) can represent a useful basis for the interpretation of hemodynamic parameters in the acutely ill patient. We prospectively collected cardiac index and paired arterial and mixed venous blood gas values in 79 acutely ill patients who were successively monitored invasively during their ICU course. For each patient, the degree of cardiac failure score and sepsis was scored at time of each measurement. A total of 122 observations were reported on a cardiac index/O2ER diagram, on which, based on physiologic data obtained during physical exercise, a line of reference was included representing equal increases in cardiac index and O2ER from normal values at rest. Patients with established heart failure fell below the line of reference. However, patients without cardiac failure or with compensated cardiac failure during adrenergic therapy fell close to the line of reference. Sepsis was associated with elevated oxygen delivery (Do2) and oxygen consumption (Vo2). Although O2ER was lower in the presence than in the absence of septic shock, patients with sepsis fell close to the line of reference. Among these patients with sepsis, O2ER was greater in patients with established heart failure than without heart failure (37.6 +/- 11.7 percent vs 21.5 +/- 4.4 percent, p < 0.01). The relationship between cardiac index and O2ER is much simpler than the relationship between Vo2 and Do2 and it avoids problems of mathematical coupling. It also allows us to refer to physiologic adaptation to changes in oxygen demand. This diagram may be useful at the bedside to facilitate the interpretation of cardiac index and to guide therapy.
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Affiliation(s)
- P G Silance
- Department of Intensive Care, Erasme University Hospital, Free University of Brussels, Belgium
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47
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Samsel RW, Lewis TH, Sanders WM, Wood LD, Schumacker PT. The effect of adrenergic agonists on the systemic response to hemorrhage. J Crit Care 1994; 9:25-33. [PMID: 8199651 DOI: 10.1016/0883-9441(94)90030-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
PURPOSE Systemic blood loss elicits a variety of reflex cardiovascular responses, which preserve cardiac output as possible and preserve arterial blood pressure when cardiac output decreases. When compensatory venoconstriction is exhausted, hemorrhage reduces oxygen delivery (QO2), and systemic vasoconstriction competes with local metabolic vasodilation to preserve tissue oxygen uptake (VO2). Through their effects on vascular tone and blood flow distribution, adrenergic agents might interfere with the physiological responses to reduced O2 delivery. This study was designed to determine the effects of dobutamine and norepinephrine on oxygen extraction and systemic vascular resistance during progressive hemorrhage. METHODS We infused dobutamine or norepinephrine into anesthetized, ventilated dogs and measured the systemic vascular resistance, oxygen consumption, and oxygen extraction ratio as oxygen delivery (blood flow) was reduced by blood withdrawal. Four groups were compared: control (saline), dobutamine (10 micrograms/kg/min), high-dose norepinephrine (1.0 microgram/kg/min), and low-dose norepinephrine (0.1 microgram/kg/min). RESULTS High-dose norepinephrine increased oxygen demand but did not alter extraction significantly at the critical point. Neither low-dose norepinephrine nor dobutamine affected oxygen extraction during hemorrhage. Dobutamine and norepinephrine both ablated the increase in systemic vascular resistance that accompanies hemorrhage. Low-dose norepinephrine was not different from control. CONCLUSIONS Norepinephrine and dobutamine appear to block reflex vasoconstriction, and mechanistic explanations for this finding remain speculative. Despite inhibition of reflex vasoconstriction, neither dobutamine nor norepinephrine significantly impaired oxygen extraction during hemorrhage.
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Affiliation(s)
- R W Samsel
- Department of Medicine, University of Chicago, Illinois
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Pourriat JL. [Sedation or ventilation?]. ANNALES FRANCAISES D'ANESTHESIE ET DE REANIMATION 1994; 13:912-3. [PMID: 7668442 DOI: 10.1016/s0750-7658(05)80942-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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