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Bedside determination of microcirculatory oxygen delivery and uptake: a prospective observational clinical study for proof of principle. Sci Rep 2021; 11:24516. [PMID: 34972827 PMCID: PMC8720096 DOI: 10.1038/s41598-021-03922-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 12/06/2021] [Indexed: 11/09/2022] Open
Abstract
Assessment of microcirculatory functional capacity is considered to be of prime importance for therapy guidance and outcome prediction in critically ill intensive care patients. Here, we show determination of skin microcirculatory oxygen delivery and consumption rates to be a feasible approach at the patient’s bedside. Real time laser-doppler flowmetry (LDF) and white light spectrophotometry (WLS) were used for assessment of thenar skin microperfusion, regional Hb and postcapillary venous oxygen saturation before and after forearm ischemia. Adapted Fick’s principle equations allowed for calculation of microcirculatory oxygen delivery and uptake. Patient groups with expected different microcirculatory status were compared [control (n = 20), sepsis-1/2 definition criteria identified SIRS (n = 10) and septic shock patients (n = 20), and the latter group further classified according to sepsis-3 definition criteria in sepsis (n = 10) and septic shock (n = 10)], respectively. In otherwise healthy controls, microcirculatory oxygen delivery and uptake approximately doubled after ischemia with maximum values (mDO2max and mVO2max) significantly lower in SIRS or septic patient groups, respectively. Scatter plots of mVO2max and mDO2max values defined a region of unphysiological low values not observed in control but in critically ill patients with the percentage of dots within this region being highest in septic shock patients. LDF and WLS combined with vasoocclusive testing reveals significant differences in microcirculatory oxygen delivery and uptake capacity between control and critically ill patients. As a clinically feasible technique for bedside determination of microcirculatory oxygen delivery and uptake, LDF and WLS combined with vasoocclusive testing holds promise for monitoring of disease progression and/or guidance of therapy at the microcirculatory level to be tested in further clinical trials. ClinicalTrials.gov: NCT01530932.
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Biochemical markers for clinical monitoring of tissue perfusion. Mol Cell Biochem 2021; 476:1313-1326. [PMID: 33387216 PMCID: PMC7921020 DOI: 10.1007/s11010-020-04019-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 12/09/2020] [Indexed: 12/25/2022]
Abstract
The assessment and monitoring of the tissue perfusion is extremely important in critical conditions involving circulatory shock. There is a wide range of established methods for the assessment of cardiac output as a surrogate of oxygen delivery to the peripheral tissues. However, the evaluation of whether particular oxygen delivery is sufficient to ensure cellular metabolic demands is more challenging. In recent years, specific biochemical parameters have been described to indicate the status between tissue oxygen demands and supply. In this review, the authors summarize the application of some of these biochemical markers, including mixed venous oxygen saturation (SvO2), lactate, central venous–arterial carbon dioxide difference (PCO2 gap), and PCO2 gap/central arterial-to-venous oxygen difference (Ca–vO2) for hemodynamic assessment of tissue perfusion. The thorough monitoring of the adequacy of tissue perfusion and oxygen supply in critical conditions is essential for the selection of the most appropriate therapeutic strategy and it is associated with improved clinical outcomes.
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Fremuth J, Kobr J, Sasek L, Pizingerova K, Zamboryova J, Sykora J. Ultrasound cardiac output monitoring in mechanically ventilated children. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2020; 165:428-434. [PMID: 33087939 DOI: 10.5507/bp.2020.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 10/06/2020] [Indexed: 11/23/2022] Open
Abstract
AIM To non-invasively identify the hemodynamic changes in critically ill children during the first 48 h following initiation of mechanical ventilation by the ultrasound cardiac output monitor (USCOM) method and compare the data in children with pulmonary and non-pulmonary pathology. MATERIALS AND METHODS This was a prospective observational study to evaluate the influence of mechanical ventilation on hemodynamic changes and to describe hemodynamic profiles of mechanically ventilated children. A total of 56 children with respiratory failure were included in the present study. Ventilated patients are divided into two groups. Group A (n=36) includes patients with pulmonary pathology. Group B (n=20) consists of patients with extra pulmonary etiology of respiratory failure. Hemodynamic parameters (cardiac index and systemic vascular resistance index) were evaluated using ultrasound cardiac output monitoring (USCOM 1A) immediately following initiation of mechanical ventilation and again at 6, 12, and 48 h. Pharmacological circulatory support (inotropes, vasopressors, levosimendan and phosphodiesterase III inhibitors) was individually and continuously modified based on real-time hemodynamic parameters and optimal fluid balance. RESULTS No significant differences in hemodynamic profiles were found between Group A and Group B. CONCLUSION The protective strategy of mechanical ventilation was not associated with significant differences in hemodynamic profiles between children ventilated for pulmonary and non-pulmonary pathologies. CLINICAL SIGNIFICANCE Hemodynamically unstable children ventilated for pulmonary pathology with the protective strategy of mechanical ventilation had a greater requirement for inotropic and combined inotropic and vasoactive circulatory support than children ventilated for non-pulmonary causes of respiratory failure.
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Affiliation(s)
- Jiri Fremuth
- Department of Pediatrics - PICU, Faculty of Medicine in Pilsen, Charles University in Prague, Czech Republic
| | - Jiri Kobr
- Department of Pediatrics - PICU, Faculty of Medicine in Pilsen, Charles University in Prague, Czech Republic
| | - Lumir Sasek
- Department of Pediatrics - PICU, Faculty of Medicine in Pilsen, Charles University in Prague, Czech Republic
| | - Katerina Pizingerova
- Department of Pediatrics - PICU, Faculty of Medicine in Pilsen, Charles University in Prague, Czech Republic
| | - Jana Zamboryova
- Department of Pediatrics - PICU, Faculty of Medicine in Pilsen, Charles University in Prague, Czech Republic
| | - Josef Sykora
- Department of Pediatrics - PICU, Faculty of Medicine in Pilsen, Charles University in Prague, Czech Republic
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Temel Yüksel İ, Acar D, Turhan U, Aslan Çetİn B, Köroğlu N, Şenol G, Tayyar A, Yüksel MA. Assessment of fetal right ventricular myocardial performance index changes following intrauterine transfusion. J Matern Fetal Neonatal Med 2019; 34:3046-3049. [PMID: 31608719 DOI: 10.1080/14767058.2019.1677595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
INTRODUCTION Severe fetal anemia may cause cardiac ischemia, reduced contractility, and dysfunction. The purpose of our study is to evaluate right ventricular myocardial performance index (MPI) before and after intrauterine transfusion (IUT) in patients who underwent this procedure because of fetal anemia due to Rh-D alloimmunization. MATERIALS AND METHODS This prospective cohort study was conducted between January 2018 and June 2019 at Kanuni Sultan Suleyman Research and Training Hospital, Istanbul, Turkey. The pregnant women who were applied IUT because of fetal anemia due to Rh-D alloimmunization in our perinatology clinic were included in the study. Fetal right ventricular MPI before and 24 h after IUT were evaluated. RESULTS A total of 28 IUTs were performed in 17 pregnant women during the study period. The isovolumetric contraction time (ICT) and isovolumetric relaxation time (IRT) values measured before IUT, were found to be significantly longer compared to the ICT and IRT values measured after IUT. The MPI values measured after transfusion was found to be higher than before transfusion. CONCLUSIONS The fetal right ventricular MPI increases 24 h after IUT. This increase in the right ventricular MPI might be used as a marker for predicting adverse fetal outcomes following IUT.
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Affiliation(s)
- İlkbal Temel Yüksel
- Department of Obstetrics and Gynecology, Kanuni Sultan Suleyman Research and Training Hospital, Istanbul, Turkey
| | - Deniz Acar
- Department of Perinatology, Sadi Konuk Research and Training Hospital, Istanbul, Turkey
| | - Uğur Turhan
- Department of Perinatology, Samsun Research and Training Hospital, Samsun, Turkey
| | - Berna Aslan Çetİn
- Department of Obstetrics and Gynecology, Kanuni Sultan Suleyman Research and Training Hospital, Istanbul, Turkey
| | - Nadiye Köroğlu
- Department of Obstetrics and Gynecology, Kanuni Sultan Suleyman Research and Training Hospital, Istanbul, Turkey
| | - Gökalp Şenol
- Department of Obstetrics and Gynecology, Kanuni Sultan Suleyman Research and Training Hospital, Istanbul, Turkey
| | - Ahmet Tayyar
- Faculty of Medicine, Department of Perinatology, Medipol University, Istanbul, Turkey
| | - Mehmet Aytaç Yüksel
- Department of Obstetrics and Gynecology, Kanuni Sultan Suleyman Research and Training Hospital, Istanbul, Turkey
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Guensch DP, Fischer K, Jung C, Hurni S, Winkler BM, Jung B, Vogt AP, Eberle B. Relationship between myocardial oxygenation and blood pressure: Experimental validation using oxygenation-sensitive cardiovascular magnetic resonance. PLoS One 2019; 14:e0210098. [PMID: 30650118 PMCID: PMC6334913 DOI: 10.1371/journal.pone.0210098] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Accepted: 12/16/2018] [Indexed: 12/14/2022] Open
Abstract
Background The relationship between mean arterial pressure (MAP) and coronary blood flow is well described. There is autoregulation within a MAP range of 60 to 140 mmHg providing near constant coronary blood flow. Outside these limits flow becomes pressure-dependent. So far, response of myocardial oxygenation to changes in pressure and flow has been more difficult to assess. While established techniques mostly require invasive approaches, Oxygenation-Sensitive (OS) Cardiovascular Magnetic Resonance (CMR) is a technique that can non-invasively assess changes in myocardial tissue oxygenation. The purpose of this study was to follow myocardial oxygenation over a wide range of blood pressure variation within and outside known coronary autoregulatory limits using OS-CMR, and to relate these data to coronary hemodynamics. Methods Ten anaesthetized swine (German Large White) underwent left-sided thoracotomy and attachment of a perivascular flow probe to the proximal left anterior descending (LAD) coronary artery for continuous measurement of blood flow (QLAD). Thereafter, animals were transferred into a 3T MRI scanner. Mean arterial pressure (MAP) was varied in 10–15 mmHg steps by administering alpha1-receptor agents phenylephrine or urapidil. For each MAP level, OS-CMR images as well as arterial and coronary sinus blood gas samples were obtained simultaneously during brief periods of apnea. Relative changes (Δ) of coronary sinus oxygen saturation (ScsO2), oxygen delivery (DO2) and demand (MVO2), extraction ratio (O2ER) and excess (Ω) from respective reference levels at a MAP of 70 mmHg were determined and were compared to %change in OS-signal intensity (OS-SI) in simultaneously acquired OS-CMR images. Results QLAD response indicated autoregulation between MAP levels of 52 mmHg (lower limit) and127 mmHg (upper limit). OS-CMR revealed a global myocardial oxygenation deficit occurring below the lower autoregulation limit, with the nadir of OS-SI at -9.0%. With MAP values surpassing 70 mmHg, relative OS-SI increased to a maximum of +10.6%. Consistent with this, ΔScsO2, ΔDO2, ΔMVO2, ΔO2ER and ΔΩ responses indicated increasing mismatch of oxygenation balance outside the autoregulated zone. Changes in global OS-CMR were significantly correlated with all of these parameters (p≤0.02) except with ΔMVO2. Conclusion OS-CMR offers a novel and non-invasive route to evaluate the effects of blood pressure variations, as well as of cardiovascular drugs and interventions, on global and regional myocardial oxygenation, as demonstrated in a porcine model. OS-CMR identified mismatch of O2 supply and demand below the lower limit of coronary autoregulation. Vasopressor induced acute hypertension did not compromise myocardial oxygenation in healthy hearts despite increased cardiac workload and O2 demand. The clinical usefulness of OS-CMR remains to be established.
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Affiliation(s)
- Dominik P. Guensch
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Institute for Diagnostic, Interventional and Paediatric Radiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- * E-mail:
| | - Kady Fischer
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Institute for Diagnostic, Interventional and Paediatric Radiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- McGill University Health Centre, Montreal, QC, Canada
| | - Christof Jung
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Samuel Hurni
- Department of Cardiovascular Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Bernhard M. Winkler
- Department of Cardiovascular Surgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Bernd Jung
- Institute for Diagnostic, Interventional and Paediatric Radiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Andreas P. Vogt
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Balthasar Eberle
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
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Integrated evaluation of hemodynamics: a novel approach for the assessment and management of preterm infants with compromised systemic circulation. J Perinatol 2018; 38:1337-1343. [PMID: 30072708 DOI: 10.1038/s41372-018-0188-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 06/19/2018] [Accepted: 07/11/2018] [Indexed: 12/25/2022]
Abstract
OBJECTIVE To establish normal reference values for tissue oxygen delivery and consumption in preterm infants and demonstrate the usefulness of the integrated evaluation of hemodynamics (IEH) in preterm infants with compromised systemic circulation (CSC). METHODS This study included 32 stable preterm infants and 6 infants (selected cases) who underwent IEH. IEH is a multimodal approach which integrates clinical parameters: data obtained from near-infrared spectroscopy (NIRS) and targeted neonatal echocardiography (TNE). RESULTS Thirty-two hemodynamically stable preterm infants underwent 57 IEH studies. The mean (10th and 90th percentiles) were 0.23 (0.14 and 0.29) for cerebral fractional oxygen extraction (crFOE), 0.2 (0.13 and 0.24) for renal fractional oxygen extraction (rnFOE), and 0.22 (0.19 and 0.27) for mesenteric fractional oxygen extraction (msFOE). The time to full clinical recovery in all sick infants after the change of management was between 4 and 48 h. CONCLUSION IEH was useful in targeting the management of preterm infants with CSC.
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Measurement of Oxygen Consumption Variations in Critically Ill Burns Patients: Are the Fick Method and Indirect Calorimetry Interchangeable? Shock 2018; 48:532-538. [PMID: 28452908 DOI: 10.1097/shk.0000000000000885] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVES To evaluate the interchangeability of oxygen consumption variations measured with the Fick equation (ΔVO2Fick) and indirect calorimetry (ΔVO2Haldane) in critically ill burns patients. METHODS Prospective observational single-center study conducted in a university hospital. Twenty-two consecutive burns patients with circulatory insufficiency and hyperlactatemia (>2 mmol/L) who required a fluid challenge (FC) were included. All patients had cardiac output monitoring (transpulmonary thermodilution technique) and were ventilated and sedated. Simultaneous measurements of VO2Fick and VO2Haldane were performed before and immediately after the FC, at rest, and in hemodynamic conditions stabilized for at least 1 h. VO2Fick and VO2Haldane were measured, respectively, with the standard formulae (using arterial and central venous saturation measured with a blood gas analyzer) and with a metabolic monitor. RESULTS Forty-four paired measurements of VO2 were obtained. At each timepoint, the median (interquartile range, 25-75) VO2Haldane values were significantly higher than the median VO2Fick values (126 (103-192) vs. 90 (66-149) mL O2/min/m (P = 0.004) before FC and 129 (105-189) vs. 80 (54-119) mL O2/min/m (P = 0.001) after FC). Correlation between the ΔVO2Fick and the ΔVO2Haldane (%) measurements was poor, with an r = 0.06, (P = 0.77). The mean bias was 8.6% [limits of agreement (LOA): -75.7%, 92.9%]. CONCLUSIONS Analysis of agreement showed poor concordance for the ΔVO2Haldane and the ΔVO2Fick (%) with a low mean bias but large and clinically unacceptable LOA. ΔVO2Haldane and ΔVO2Fick (%) are not interchangeable in these conditions.
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Muthuchellappan R, Shaikh NA, Surve RM, Ganne URS, Philip M. Regional cerebral tissue oxygen saturation changes following blood transfusion in neuro-intensive care unit patients - a pilot observational study. Transfus Med 2018; 28:304-309. [PMID: 29318718 DOI: 10.1111/tme.12504] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 12/04/2017] [Accepted: 12/05/2017] [Indexed: 01/28/2023]
Abstract
BACKGROUND Although central venous oxygen saturation (ScvO2 ) is used to decide on red blood cell (RBC) transfusion, whether its improvement is associated with parallel improvement in cerebral oxygenation is not adequately studied. This study looked at changes in regional cerebral tissue oxygen saturation (rSO2 ) following RBC transfusion in neuro-intensive care unit (ICU) patients. METHODS In this prospective observational pilot study, rSO2 was measured in adult neuro-ICU patients before RBC transfusion, at the end and at 6, 12, 18 and 24 h after RBC transfusion. rSO2 measurements were taken using cerebral oximetry on both sides of the hemicraniums. Haemoglobin, central venous pressure, ScvO2 and temperature were recorded during the study period. Arterial oxygen content, central venous oxygen content and cerebral fractional oxygen extraction were calculated. Mann Whitney U test was used to study the changes in variables at baseline and at 24 h following RBC transfusion. Friedman's test was used to study changes in parameters from baseline to 24 h post-transfusion. A P value of <0·05 was considered to be significant. RESULTS The data from 13 subjects were analysed. rSO2 increased significantly following RBC transfusion on both sides of the brain (P = 0·002, P = 0·007), with a corresponding decrease in cerebral fractional oxygen extraction (P = 0·001, P = 0·007). CONCLUSIONS RBC transfusion increased rSO2 significantly on both sides of the brain. As patients' outcomes were not studied, whether this increase in regional cerebral oxygen saturation is beneficial or if it is because of excess DO2 is still unclear. Further studies are required to clarify this issue.
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Affiliation(s)
- R Muthuchellappan
- Department of Neuroanaesthesia and Neurocritical Care, National Institute of Mental Health and NeuroSciences (NIMHANS), Bengaluru, India
| | - N A Shaikh
- Department of Anaesthesiology and Critical Care, Dr Ram Manohar Lohia Institute of Medical Sciences, Lucknow, India
| | - R M Surve
- Department of Neuroanaesthesia and Neurocritical Care, National Institute of Mental Health and NeuroSciences (NIMHANS), Bengaluru, India
| | - U R S Ganne
- Department of Neuroanaesthesia and Neurocritical Care, National Institute of Mental Health and NeuroSciences (NIMHANS), Bengaluru, India
| | - M Philip
- Department of Biostatistics, National Institute of Mental Health and NeuroSciences (NIMHANS), Bengaluru, India
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Giustiniano E, Procopio F, Ruggieri N, Grimaldi S, Torzilli G, Raimondi F. Impact of the FloTrac/VigileoTM Monitoring on Intraoperative Fluid Management and Outcome after Liver Resection. Dig Surg 2017; 35:435-441. [PMID: 29073613 DOI: 10.1159/000481406] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 09/10/2017] [Indexed: 12/16/2022]
Abstract
BACKGROUNDS Perioperative fluid-therapy is a still a debated issue. In hepatic surgery, volume load must be strictly monitored to assure both a safe hemodynamics and low central venous pressure (CVP) to limit the backflow bleeding. Retrospectively, we compared intraoperative fluid management before and after the adoption of a semi-invasive hemodynamic monitoring. METHODS We compared patients submitted to liver resection monitored by FloTrac/VigileoTM (group A) vs. patients who did not (group B). We searched for differences about hemodynamics, fluid therapy and outcome. RESULTS Three hundred fifty-five patients underwent hepatic resection due to neoplasm: group A - n = 179 and group B - n = 176. At the end of the resection, patients of group A showed a higher mean arterial pressure (MAP) than group B (74 ± 12 vs. 49.4 ± 8 mm Hg, respectively; p < 0.001). Cardiac index and stroke volume variation in group A were within a normal range. Fluid input was higher in group B than in group A (12.0 ± 3.4 vs. 7.6 ± 3.1 mL/kg/h, respectively; p < 0.001) and fluid balance was significantly different: group A -400 ± 1,527 vs. group B 326 ± 1,527 mL (p < 0.001). Group B showed a greater number of cases complicated outcomes (36 vs. 20; p = 0.014). Considering only those subjects who were able to reach their hemodynamic targets (MAP ≥65 mm Hg and CVP ≤7 mm Hg), we found similar data. CONCLUSIONS Patients who received a monitored fluid therapy experienced a safer outcome.
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Affiliation(s)
- Enrico Giustiniano
- Humanitas Research Hospital-Department of Anesthesia and Intensive Care, Milan, Italy
| | - Fabio Procopio
- Humanitas Research Hospital-Department of Hepatobiliary and General Surgery, Milan, Italy
| | - Nadia Ruggieri
- Humanitas Research Hospital-Department of Anesthesia and Intensive Care, Milan, Italy
| | - Stefania Grimaldi
- Humanitas Research Hospital-Department of Anesthesia and Intensive Care, Milan, Italy
| | - Guido Torzilli
- Humanitas Research Hospital-Department of Hepatobiliary and General Surgery, Milan, Italy
| | - Ferdinando Raimondi
- Humanitas Research Hospital-Department of Anesthesia and Intensive Care, Milan, Italy
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Licker M, Triponez F, Ellenberger C, Karenovics W. Less Fluids and a More Physiological Approach. Turk J Anaesthesiol Reanim 2016; 44:230-232. [PMID: 27909601 DOI: 10.5152/tjar.2016.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Marc Licker
- Department of Anesthesiology, Pharmacology and Intensive Care, University Hospital of Geneva, Switzerland
| | - Frédéric Triponez
- Department of Thoracic and Endocrine Surgery, University Hospital of Geneva, Switzerland
| | - Christoph Ellenberger
- Department of Anesthesiology, Pharmacology and Intensive Care, University Hospital of Geneva, Switzerland
| | - Wolfram Karenovics
- Department of Thoracic and Endocrine Surgery, University Hospital of Geneva, Switzerland
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Chirichella TJ, Dunham CM, Zimmerman MA, Phelan EM, Mandell MS, Conzen KD, Kelley SE, Nydam TL, Bak TE, Kam I, Wachs ME. Donor preoperative oxygen delivery and post-extubation hypoxia impact donation after circulatory death hypoxic cholangiopathy. World J Gastroenterol 2016; 22:3392-3403. [PMID: 27022221 PMCID: PMC4806197 DOI: 10.3748/wjg.v22.i12.3392] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Revised: 10/06/2015] [Accepted: 12/01/2015] [Indexed: 02/06/2023] Open
Abstract
AIM: To evaluate donation after circulatory death (DCD) orthotopic liver transplant outcomes [hypoxic cholangiopathy (HC) and patient/graft survival] and donor risk-conditions.
METHODS: From 2003-2013, 45 DCD donor transplants were performed. Predonation physiologic data from UNOS DonorNet included preoperative systolic and diastolic blood pressure, heart rate, pH, SpO2, PaO2, FiO2, and hemoglobin. Mean arterial blood pressure was computed from the systolic and diastolic blood pressures. Donor preoperative arterial O2 content was computed as [hemoglobin (gm/dL) × 1.37 (mL O2/gm) × SpO2%) + (0.003 × PaO2)]. The amount of preoperative donor red blood cell transfusions given and vasopressor use during the intensive care unit stay were documented. Donors who were transfused ≥ 1 unit of red-cells or received ≥ 2 vasopressors in the preoperative period were categorized as the red-cell/multi-pressor group. Following withdrawal of life support, donor ischemia time was computed as the number-of-minutes from onset of diastolic blood pressure < 60 mmHg until aortic cross clamping. Donor hypoxemia time was the number-of-minutes from onset of pulse oximetry < 80% until clamping. Donor hypoxia score was (ischemia time + hypoxemia time) ÷ donor preoperative hemoglobin.
RESULTS: The 1, 3, and 5 year graft and patient survival rates were 83%, 77%, 60%; and 92%, 84%, and 72%, respectively. HC occurred in 49% with 16% requiring retransplant. HC occurred in donors with increased age (33.0 ± 10.6 years vs 25.6 ± 8.4 years, P = 0.014), less preoperative multiple vasopressors or red-cell transfusion (9.5% vs 54.6%, P = 0.002), lower preoperative hemoglobin (10.7 ± 2.2 gm/dL vs 12.3 ± 2.1 gm/dL, P = 0.017), lower preoperative arterial oxygen content (14.8 ± 2.8 mL O2/100 mL blood vs 16.8 ± 3.3 mL O2/100 mL blood, P = 0.049), greater hypoxia score >2.0 (69.6% vs 25.0%, P = 0.006), and increased preoperative mean arterial pressure (92.7 ± 16.2 mmHg vs 83.8 ± 18.5 mmHg, P = 0.10). HC was independently associated with age, multi-pressor/red-cell transfusion status, arterial oxygen content, hypoxia score, and mean arterial pressure (r2 = 0.6197). The transplantation rate was greater for the later period with more liberal donor selection [era 2 (7.1/year)], compared to our early experience [era 1 (2.5/year)]. HC occurred in 63.0% during era 2 and in 29.4% during era 1 (P = 0.03). Era 2 donors had longer times for extubation-to-asystole (14.4 ± 4.7 m vs 9.3 ± 4.5 m, P = 0.001), ischemia (13.9 ± 5.9 m vs 9.7 ± 5.6 m, P = 0.03), and hypoxemia (16.0 ± 5.1 m vs 11.1 ± 6.7 m, P = 0.013) and a higher hypoxia score > 2.0 rate (73.1% vs 28.6%, P = 0.006).
CONCLUSION: Easily measured donor indices, including a hypoxia score, provide an objective measure of DCD liver transplantation risk for recipient HC. Donor selection criteria influence HC rates.
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Najafi M, Faraoni D. Hemoglobin optimization and transfusion strategies in patients undergoing cardiac surgery. World J Cardiol 2015; 7:377-382. [PMID: 26225197 PMCID: PMC4513488 DOI: 10.4330/wjc.v7.i7.377] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 04/07/2015] [Accepted: 05/06/2015] [Indexed: 02/06/2023] Open
Abstract
Although red blood cells (RBCs) transfusion is sometimes associated with adverse reactions, anemia could also lead to increased morbidity and mortality in high-risk patients. For these reasons, the definition of perioperative strategies that aims to detect and treat preoperative anemia, prevent excessive blood loss, and define “optimal” transfusion algorithms is crucial. Although the treatment with preoperative iron and erythropoietin has been recommended in some specific conditions, several controversies exist regarding the benefit-to-risk balance associated with these treatments. Further studies are needed to better define the indications, dosage, and route of administration for preoperative iron with or without erythropoietin supplementation. Although restrictive transfusion strategies in patients undergoing cardiac surgery have been shown to effectively reduce the incidence and the amount of RBCs transfusion without increase in side effects, some high-risk patients (e.g., symptomatic acute coronary syndrome) could benefit from higher hemoglobin concentrations. Despite all efforts made last decade, a significant amount of work remains to be done to improve hemoglobin optimization and transfusion strategies in patients undergoing cardiac surgery.
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Briganti A, Portela D, Grasso S, Sgorbini M, Tayari H, Bassini JF, Vitale V, Romano M, Crovace A, Breghi G, Staffieri F. Accuracy of different oxygenation indices in estimating intrapulmonary shunting at increasing infusion rates of dobutamine in horses under general anaesthesia. Vet J 2015; 204:351-6. [DOI: 10.1016/j.tvjl.2015.04.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 03/10/2015] [Accepted: 04/06/2015] [Indexed: 11/25/2022]
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Raisis AL, Smart L, Drynan E, Hosgood G. Cardiovascular function during maintenance of anaesthesia with isoflurane or alfaxalone infusion in greyhounds experiencing blood loss. Vet Anaesth Analg 2015; 42:133-41. [DOI: 10.1111/vaa.12190] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Accepted: 01/02/2014] [Indexed: 11/30/2022]
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Tissue ischemia microdialysis assessments following severe traumatic haemorrhagic shock: lactate/pyruvate ratio as a new resuscitation end point? BMC Anesthesiol 2014; 14:118. [PMID: 25580084 PMCID: PMC4289551 DOI: 10.1186/1471-2253-14-118] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 12/10/2014] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Intensive care of severe trauma patients focuses on the treatment of haemorrhagic shock. Tissues should be perfused sufficiently with blood and with sufficient oxygen content to ensure adequate tissue oxygen delivery. Tissue metabolism can be monitored by microdialysis, and the lactate/pyruvate ratio (LPR) may be used as a tissue ischemia marker. The aim of this study was to determine the adequate cardiac output and haemoglobin levels that avoid tissue ischemia. METHODS Adult patients with serious traumatic haemorrhagic shock were enrolled in this prospective observational study. The primary observed parameters included haemoglobin, cardiac output, central venous saturation, arterial lactate and the tissue lactate/pyruvate ratio. RESULTS Forty-eight patients were analysed. The average age of the patients was 39.8 ± 16.7, and the average ISS was 43.4 ± 12.2. Hb < 70 g/l was associated with pathologic arterial lactate, ScvO2 and LPR. Tissue ischemia (i.e., LPR over 25) developed when CI ≤ 3.2 l/min/m(2) and Hb between 70 and 90 g/l were observed. Severe tissue ischemia events were recorded when the Hb dropped below 70 g/l and CI was 3.2-4.8 l/min/m(2). CI ≥ 4.8 l/min/m(2) was not found to be connected with tissue ischemia, even when Hb ≤ 70 g/l. CONCLUSION LPR could be a useful marker to manage traumatic haemorrhagic shock therapies. In initial traumatic haemorrhagic shock treatments, it may be better to maintain CI ≥ 3.2 l/min/m(2) and Hb ≥ 70 g/l to avoid tissue ischemia. LPR could also be a useful transfusion trigger when it may demonstrate ischemia onset due to low local DO2 and early reveal low/no tissue perfusion.
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16
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Du W, Liu DW, Wang XT, Long Y, Chai WZ, Zhou X, Rui X. Combining central venous-to-arterial partial pressure of carbon dioxide difference and central venous oxygen saturation to guide resuscitation in septic shock. J Crit Care 2014; 28:1110.e1-5. [PMID: 24216336 DOI: 10.1016/j.jcrc.2013.07.049] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 07/05/2013] [Accepted: 07/08/2013] [Indexed: 01/01/2023]
Abstract
PURPOSE Central venous oxygen saturation (Scvo2) is a useful therapeutic target when treating septic shock. We hypothesized that combining Scvo2 and central venous-to-arterial partial pressure of carbon dioxide difference (△Pco2) may provide additional information about survival. MATERIALS AND METHODS We performed a retrospective analysis of 172 patients treated for septic shock. All patients were treated using goal-directed therapy to achieve Scvo2 ≥ 70%. After 6 hours of treatment, we divided patients into 4 groups based on Scvo2 (<70% or ≥ 70%) and △Pco2 (<6 mm Hg or ≥ 6 mm Hg). RESULTS Overall, 28-day mortality was 35.5%. For patients in whom the Scvo2 target was not achieved at 6 hours, mortality was 50.0%, compared with 29.5% in those in whom Scvo2 exceeded 70% (P = .009). In patients with Scvo2 ≥ 70%, mortality was lower if △Pco2 was <6 mm Hg than if △Pco2 was ≥ 6 mm Hg (56.1% vs 16.1%, respectively; P < .001) and 6-hour lactate clearance was superior (0.01 ± 0.61 vs 0.21 ± 0.31, respectively; P = .016). CONCLUSIONS The combination of Scvo2 and △Pco2 appears to predict outcome in critically ill patients resuscitated from septic shock better than Scvo2 alone. Patients who meet both targets appear to clear lactate more efficiently.
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Affiliation(s)
- Wei Du
- 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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17
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Gergely M, Ablonczy L, Székely EA, Sápi E, Gál J, Szatmári A, Székely A. Assessment of global tissue perfusion and oxygenation in neonates and infants after open-heart surgery. Interact Cardiovasc Thorac Surg 2014; 18:426-31. [PMID: 24421206 DOI: 10.1093/icvts/ivt537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVES Monitoring and preserving adequate perfusion and oxygen balance is a primary objective of critical care. This prospective observational study aimed to assess the relationship between global haemodynamic parameters and variables reflecting tissue oxygenation during the early period following corrective cardiac surgery in neonates and infants. The postoperative time course of oxygen delivery and consumption was evaluated. As surrogate markers of oxygen balance, the central venous oxygen saturation (ScvO2) and venoarterial PCO2 difference (PvaCO2) were thoroughly investigated. METHODS Thirteen children <1 year of age who underwent open-heart surgery were prospectively enrolled. In addition to conventional postoperative monitoring, transpulmonary thermodilution (TPTD) was used to monitor cardiac output and calculate oxygen delivery and consumption. In parallel with each TPTD measurement, arterial and central venous blood gas values were recorded. Global haemodynamic parameters and oxygenation measurements were compared with weighted linear regression statistics and Pearson's correlation coefficient. RESULTS Data from 145 TPTD measurements and 304 blood gas samples were recorded. The early postoperative period was characterized by a supply-dependent oxygen consumption, as demonstrated by the direct correlation between the change in oxygen delivery and consumption (r = 0.62, P < 0.001). Regarding haemodynamic parameters, none of the heart rate, mean arterial pressure or cardiac index correlated with the measured ScvO2. However, the ScvO2 and PvaCO2 were found to correlate significantly (r = -0.49, P < 0.001), and both strongly related to oxygen extraction. CONCLUSIONS Both the ScvO2 and PvaCO2 are reliable and comparable parameters in following tissue oxygen balance during the early postoperative course after open-heart surgery in neonates and infants. As part of multiparameter monitoring, our data highlight the importance of regular ScvO2 measurements and PvaCO2 calculations in paediatric intensive care.
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Affiliation(s)
- Mihály Gergely
- Department of Anesthesiology and Intensive Therapy, Gottsegen György Hungarian Institute of Cardiology, Budapest, Hungary
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18
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Kuiper AN, Trof RJ, Groeneveld ABJ. Mixed venous O2 saturation and fluid responsiveness after cardiac or major vascular surgery. J Cardiothorac Surg 2013; 8:189. [PMID: 24053433 PMCID: PMC3848814 DOI: 10.1186/1749-8090-8-189] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 09/17/2013] [Indexed: 11/10/2022] Open
Abstract
Background It is unclear if and how SvO2 can serve as an indicator of fluid responsiveness in patients after cardiac or major vascular surgery. Methods This was a substudy of a randomized single-blinded clinical trial reported earlier on critically ill patients with clinical hypovolemia after cardiac or major vascular surgery. Colloid fluid loading was done for 90 min, guided by changes in pulmonary artery occlusion pressure (PAOP) or central venous pressure (CVP). Fluid responsiveness was defined as ≥15% increase in cardiac index (CI). Hemodynamics, including transpulmonary dilution-derived global end-diastolic volume index (GEDVI) and global ejection fraction (GEF), were measured and blood samples taken. Results Whereas baseline SvO2 (>70% in 68% of patients) did not differ, the SvO2 increased in patients responding to fluid loading (≥15% in CI in n = 26) versus those not responding (n = 11; P = 0.03). The increase in GEDVI was also greater in responders (P = 0.005). The area under the receiver operating characteristic curve for fluid responsiveness of changes in SvO2 was 0.73 (P = 0.007), with an optimal cutoff of 2%, and of those in GEDVI 0.82 (P < 0.001), while the areas did not differ. However, the value of SvO2 increases to reflect CI increases with fluid loading was greatest when GEF was ≤20% (in 53% of patients). Conclusions An increase in SvO2 ≥2%, irrespective of a relatively high baseline value, can thus be used as a monitor of fluid responsiveness in clinically hypovolemic patients after cardiac or major vascular surgery, particularly in those with systolic cardiac dysfunction. Fluid responsiveness concurs with increased tissue O2 delivery.
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Affiliation(s)
- Arjan N Kuiper
- Departments of Intensive Care, VU University Medical Centre, Amsterdam, The Netherlands.
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19
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Haouzi P, Van de Louw A. Uncoupling mitochondrial activity maintains body [Formula: see text] during hemorrhage-induced O2 deficit in the anesthetized rat. Respir Physiol Neurobiol 2013; 186:87-94. [PMID: 23333818 DOI: 10.1016/j.resp.2012.12.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 12/20/2012] [Accepted: 12/21/2012] [Indexed: 01/25/2023]
Abstract
During a hemorrhagic shock (HS), O2 uptake ( [Formula: see text] ) decreases as soon as the rate of O2 delivery ( [Formula: see text] ) drops below a "critical level", a response accounted for by the reduction in mitochondrial O2supply. In urethane-anesthetized rats, [Formula: see text] was decreased within 20min from 21.5 to 2.8mlmin(-1) by slowly withdrawing 18mlkg(-1) of blood. This led to a reduction in [Formula: see text] from 6.1 to 2.4mlmin(-1) (n=5, p<0.01). Decoupling mitochondrial oxidative activity by injecting 2,4-DNP (6mgkg(-1), iv) before HS elevated [Formula: see text] to 11.9±1.2mlmin(-1) (n=6, p<0.01), which remained above control HS values throughout most of the hemorrhage. This was associated with higher levels of O2 extraction, cardiac output and ventilation than in control HS. [Formula: see text] relationship was shifted upward and to the left following DNP. In conclusion, cellular and systemic mechanisms, decreasing O2demand, account for a large part of HS induced [Formula: see text] decline resulting in an additional reduction in [Formula: see text] .
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Affiliation(s)
- Philippe Haouzi
- Pennsylvania State University, College of Medicine, Division of Pulmonary and Critical Care Medicine, Penn State Hershey Medical Center, Hershey, PA, United States.
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Radicioni M, Troiani S, Mezzetti D. Functional echocardiographic assessment of myocardial performance in anemic premature infants: a pilot study. Pediatr Cardiol 2012; 33:554-61. [PMID: 22274640 DOI: 10.1007/s00246-012-0154-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 12/09/2011] [Indexed: 10/14/2022]
Abstract
This prospective observational study conducted in a neonatal intensive care unit aimed to evaluate echocardiographic changes provoked by anemia and transfusion of packed red blood cells (pRBCs) in premature infants. In this study, 32 anemic premature infants had serial echocardiographic assessment of left ventricular (LV) systolic performance, LV preload, and afterload immediately before, within 48 h, and up to 120 h after the transfusion of pRBCs. Pretransfusional evaluations also were compared with similar assessments of 71 nonanemic inpatient premature infants analogous for sex, gestational age at birth, and postnatal age. Left ventricular systolic performance was estimated from fractional shortening, LV output, and LV myocardial performance index (LVMPI). The LV preload was estimated from the LV end-diastolic dimension and the ratio of left atrium-to-aortic root dimension (LA/Ao ratio). The LV afterload was estimated from end-systolic wall stress. The LVMPI was found to decrease with increasing corrected gestational age in both the nonanemic (R = 0.173; p = 0.03) and anemic (R = 0.460; p = 0.007) infants. The LVMPI was the only index that changed after transfusion of pRBCs, decreasing in the younger anemic infants (p = 0.011) and increasing in the older anemic infants (p = 0.012). Finally, a significant inverse relationship between pre- and posttransfusional LVMPI values (R = 0.730; p < 0.001) was noted. The LVMPI may allow for identification of preterm infants more likely to be helped by transfusion of pRBCs.
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Affiliation(s)
- Maurizio Radicioni
- Neonatal Intensive Care Unit, S. Maria della Misericordia Hospital of Perugia, Azienda Ospedaliera di Perugia, S. Andrea delle Fratte, 06156 Perugia, Italy.
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Bonanno FG. Clinical pathology of the shock syndromes. J Emerg Trauma Shock 2011; 4:233-43. [PMID: 21769211 PMCID: PMC3132364 DOI: 10.4103/0974-2700.82211] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 01/09/2011] [Indexed: 01/01/2023] Open
Abstract
The clinical aspects of shock syndromes are described from their inception as compensated physiology to a stage of decompensation. The clinical significance of hypotension, fluid-responsive and non fluid-responsive hypotension, is discussed. Untimely or inadequate treatment leads to persistent subclinical shock despite adjustments of the macrohemodynamic variables, which evolves in a second hit of physiological deterioration if not aggressively managed. Irreversible shock ensues as consequence of direct hit or as result of inadequate or delayed treatment and is characterized by drug-resistant hypotension.
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Guo Y, Lin CX, Lau WY, Long D, Lao CY, Wen Z, Lai EC, Wang XJ, Li LQ, Qing X. Hemodynamics and oxygen transport dynamics during hepatic resection at different central venous pressures in a pig model. Hepatobiliary Pancreat Dis Int 2011; 10:516-20. [PMID: 21947726 DOI: 10.1016/s1499-3872(11)60087-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Although low central venous pressure (CVP) has been used to minimize blood loss during hepatectomy, the impact of variations of CVP on the rate of blood loss and on the perfusion of end-organs has not been evaluated. This animal study aimed to evaluate the hemodynamics and oxygen transport changes during hepatic resection at different CVP levels. METHODS Forty-eight anesthetized Bama miniature pigs were divided into 8 groups with CVP during hepatic resection controlled at 0 to <1, 1 to <2, 2 to <3, 3 to <4, 4 to <5, 5 to <6, 6 to <7, and 7 to <8 cmH2O. Intergroup comparisons were made for hemodynamic parameters, oxygen transport dynamics, and the rate of blood loss. RESULTS The rate of blood loss and the hepatic venous pressure during hepatic resection were almost linearly related to the CVP. A significant drop in the mean arterial pressure, cardiac output, and cardiac index occurred between CVP ≥2 and <2 cmH2O. Oxygen delivery (DO2), oxygen consumption (VO2) and oxygen extraction ratio (ERO2) remained relatively constant between CVPs of 2 to <8 cmH2O. There was a significant drop in DO2 when the CVP was <2 cmH2O. There was also a significant drop in VO2 and ExO2 when the CVP was <1 cmH2O. CONCLUSION The optimal CVP for hepatic resection is 2 to 3 cmH2O.
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Affiliation(s)
- Ya Guo
- Department of Anesthesiology, First Affiliated Hospital, Guangxi Medical University, Nanning 530021, China.
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Donovan L, Welford SM, Haaga J, LaManna J, Strohl KP. Hypoxia--implications for pharmaceutical developments. Sleep Breath 2010; 14:291-8. [PMID: 20625934 DOI: 10.1007/s11325-010-0368-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 05/11/2010] [Accepted: 05/12/2010] [Indexed: 11/30/2022]
Abstract
Cells sense oxygen availability using not only the absolute value for cellular oxygen in regard to its energetic and metabolic functions, but also the gradient from the cell surface to the lowest levels in the mitochondria. Signals are used for regulatory purposes locally as well as in the generation of cellular, tissue, and humoral remodeling. Lowered oxygen availability (hypoxia) is theoretically important in the consideration of pharmacology because (1) hypoxia can alter cellular function and thereby the therapeutic effectiveness of the agent, (2) therapeutic agents may potentiate or protect against hypoxia-induced pathology, (3) hypoxic conditions may potentiate or mitigate drug-induced toxicity, (4) hypoxia may alter drug metabolism and thereby therapeutic effectiveness, and (5) therapeutic agents might alter the relative coupling of blood flow and energy metabolism in an organ. The prototypic biochemical effect of hypoxia is related to its known role as a cofactor in a number of enzymatic reactions, e.g., oxidases and oxygenases, which are affected independently from the bioenergetic effect of low oxygen on energetic functions. The cytochrome P-450 family of enzymes is another example. Here, there is a direct effect of oxygen availability on the conformation of the enzyme, thereby altering the metabolism of drug substrates. Indirectly, the NADH/NAD+ ratio is increased with 10% inspired oxygen, leading not only to reduced oxidation of ethanol but also to reduction of azo- and nitro-compounds to amines and disulfides to sulfhydryls. With chronic hypoxia, many of these processes are reversed, suggesting that hypoxia induces the drug-metabolizing systems. Support for this comes from observations that hypoxia can induce the hypoxic inducible factors which in turn alters transcription and function of some but not all cytochrome P-450 isoforms. Hypoxia is identified as a cofactor in cancer expression and metastatic potential. Thus, the effects of hypoxia play an important role in pharmacology, and the signaling pathways that are affected by hypoxia could become new targets for novel therapy or avenues for prevention.
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Affiliation(s)
- Lucas Donovan
- Case Western Reserve University School of Medicine, Cleveland, OH, USA
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Ho KM, Harding R, Chamberlain J, Bulsara M. A comparison of central and mixed venous oxygen saturation in circulatory failure. J Cardiothorac Vasc Anesth 2008; 24:434-9. [PMID: 18834813 DOI: 10.1053/j.jvca.2007.10.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The purpose of this study was to evaluate whether central venous oxygen saturation can be used as an alternative to mixed venous oxygen saturation in patients with cardiogenic and septic shock. DESIGN Prospective clinical study. SETTING A tertiary intensive care unit in a university hospital. PARTICIPANTS Twenty patients with cardiogenic or septic shock requiring a pulmonary artery catheter and inotropic support. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS The central venous oxygen saturation overestimated the mixed venous oxygen saturation by a mean bias (or an absolute difference) of 6.9%, and the 95% limits of agreement were large (-5.0% to 18.8%). The difference between central and mixed venous oxygen saturation appeared to be more significant when mixed venous oxygen saturation was <70%. The changes in central and mixed venous oxygen saturation did not follow the line of perfect agreement closely in different clinical conditions. The central or mixed venous oxygen saturation had a significant ability to predict the status of cardiac output state, but this ability was reduced when the effect of hyperoxia was not considered. CONCLUSION Central and mixed venous oxygen saturation measurements are not interchangeable numerically.
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Affiliation(s)
- Kwok M Ho
- Department of Intensive Care, Royal Perth Hospital, Perth, WA, Australia.
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