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Minneci PC, Deans KJ, Hansen B, Parent C, Romines C, Gonzales DA, Ying SX, Munson P, Suffredini AF, Feng J, Solomon MA, Banks SM, Kern SJ, Danner RL, Eichacker PQ, Natanson C, Solomon SB. A canine model of septic shock: balancing animal welfare and scientific relevance. Am J Physiol Heart Circ Physiol 2007; 293:H2487-500. [PMID: 17644570 DOI: 10.1152/ajpheart.00589.2007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A shock canine pneumonia model that permitted relief of discomfort with the use of objective criteria was developed and validated. After intrabronchial Staphylococcus aureus challenge, mechanical ventilation, antibiotics, fluids, vasopressors, sedatives, and analgesics were titrated based on algorithms for 96 h. Increasing S. aureus (1 to 8 x 10(9) colony-forming units/kg) produced decreasing survival rates (P = 0.04). From 4 to 96 h, changes in arterial-alveolar oxygen gradients, mean pulmonary artery pressure, IL-1, serum sodium levels, mechanical ventilation, and vasopressor support were ordered based on survival time [acute nonsurvivors (< or =24 h until death, n = 8) > or = subacute nonsurvivors (>24 to 96 h until death, n = 8) > or = survivors (> or =96 h until death, n = 22) (all P < 0.05)]. In the first 12 h, increases in lactate and renal abnormalities were greatest in acute nonsurvivors (all P < 0.05). Compared with survivors, subacute nonsurvivors had greater rises in cytokines and liver enzymes and greater falls in platelets, white cell counts, pH, and urine output from 24 to 96 h (all P < 0.05). Importantly, these changes were not attributable to dosages of sedation, which decreased in nonsurvivors [survivors vs. nonsurvivors: 5.0 +/- 1.0 vs. 3.8 +/- 0.7 ml x h(-1) x (fentanyl/midazolam/ medetomidine)(-1); P = 0.02]. In this model, the pain control regimen did not mask changes in metabolic function and lung injury or the need for more hemodynamic and pulmonary support related to increasing severity of sepsis. The integration into this model of both specific and supportive titrated therapies routinely used in septic patients may provide a more realistic setting to evaluate therapies for sepsis.
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MESH Headings
- Analgesics/pharmacology
- Animal Welfare
- Animals
- Anti-Bacterial Agents/pharmacology
- Biomedical Research/methods
- Blood Chemical Analysis
- Blood Proteins/metabolism
- Cytokines/blood
- Disease Models, Animal
- Dogs
- Fluid Therapy
- Hematologic Tests
- Hypnotics and Sedatives/pharmacology
- Kidney Diseases/microbiology
- Kidney Function Tests
- Liver Diseases/microbiology
- Liver Function Tests
- Pneumonia, Staphylococcal/blood
- Pneumonia, Staphylococcal/complications
- Pneumonia, Staphylococcal/microbiology
- Pneumonia, Staphylococcal/physiopathology
- Pneumonia, Staphylococcal/therapy
- Reproducibility of Results
- Respiration, Artificial
- Severity of Illness Index
- Shock, Septic/blood
- Shock, Septic/complications
- Shock, Septic/microbiology
- Shock, Septic/physiopathology
- Shock, Septic/therapy
- Staphylococcus aureus
- Time Factors
- Vasoconstrictor Agents
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Affiliation(s)
- Peter C Minneci
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland 20892, USA
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Minneci PC, Deans KJ, Banks SM, Costello R, Csako G, Eichacker PQ, Danner RL, Natanson C, Solomon SB. Differing effects of epinephrine, norepinephrine, and vasopressin on survival in a canine model of septic shock. Am J Physiol Heart Circ Physiol 2004; 287:H2545-54. [PMID: 15319205 DOI: 10.1152/ajpheart.00450.2004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
During sepsis, limited data on the survival effects of vasopressors are available to guide therapy. Therefore, we compared the effects of three vasopressors on survival in a canine septic shock model. Seventy-eight awake dogs infected with differing doses of intraperitoneal Escherichia coli to produce increasing mortality were randomized to receive epinephrine (0.2, 0.8, or 2.0 μg·kg−1·min−1), norepinephrine (0.2, 1.0, or 2.0 μg·kg−1·min−1), vasopressin (0.01 or 0.04 U/min), or placebo in addition to antibiotics and fluids. Serial hemodynamic and biochemical variables were measured. Increasing doses of bacteria caused progressively greater decreases in survival ( P < 0.06), mean arterial pressure (MAP) ( P < 0.05), cardiac index (CI) ( P < 0.02), and ejection fraction (EF) ( P = 0.02). The effects of epinephrine on survival were significantly different from those of norepinephrine and vasopressin ( P = 0.03). Epinephrine had a harmful effect on survival that was significantly related to drug dose ( P = 0.02) but not bacterial dose. Norepinephrine and vasopressin had beneficial effects on survival that were similar at all drug and bacteria doses. Compared with concurrent infected controls, epinephrine caused greater decreases in CI, EF, and pH, and greater increases in systemic vascular resistance and serum creatinine than norepinephrine and vasopressin. These epinephrine-induced changes were significantly related to the dose of epinephrine administered. In this study, the effects of vasopressors were independent of severity of infection but dependent on the type and dose of vasopressor used. Epinephrine adversely affected organ function, systemic perfusion, and survival compared with norepinephrine and vasopressin. In the ranges studied, norepinephrine and vasopressin have more favorable risk-benefit profiles than epinephrine during sepsis.
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Affiliation(s)
- Peter C Minneci
- Critical Care Medicine Department, National Institutes of Health, 10 Center Dr., Bldg 10, Rm 7D43, Bethesda, MD 20892, USA.
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Feihl F, Waeber B, Liaudet L. Is nitric oxide overproduction the target of choice for the management of septic shock? Pharmacol Ther 2001; 91:179-213. [PMID: 11744067 DOI: 10.1016/s0163-7258(01)00155-3] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Sepsis is a heterogeneous class of syndromes caused by a systemic inflammatory response to infection. Septic shock, a severe form of sepsis, is associated with the development of progressive damage in multiple organs, and is a leading cause of patient mortality in intensive care units. Despite important advances in understanding its pathophysiology, therapy remains largely symptomatic and supportive. A decade ago, the overproduction of nitric oxide (NO) had been discovered as a potentially important event in this condition. As a result, great hopes arose that the pharmacological inhibition of NO synthesis could be developed into an efficient, mechanism-based therapeutic approach. Since then, an extraordinary effort by the scientific community has brought a deeper insight regarding the feasibility of this goal. Here we present in summary form the present state of knowledge of the biological chemistry and physiology of NO. We then proceed to a systematic review of experimental and clinical data, indicating an up-regulation of NO production in septic shock; information on the role of NO in septic shock, as provided by experiments in transgenic mice that lack the ability to up-regulate NO production; effects of pharmacological inhibitors of NO production in various experimental models of septic shock; and relevant clinical experience. The accrued evidence suggests that the contribution of NO to the pathophysiology of septic shock is highly heterogeneous and, therefore, difficult to target therapeutically without appropriate monitoring tools, which do not exist at present.
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Affiliation(s)
- F Feihl
- Division of Pathophysiology and Medical Teaching, Department of Internal Medicine, University Hospital, PPA, BH19-317, CHUV, CH 1011 Lausanne, Switzerland.
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Mitaka C, Hirata Y, Yokoyama K, Imai T. L-canavanine, a selective inhibitor of inducible NO synthase, increases plasma endothelin-1 concentrations in dogs with endotoxic shock. J Crit Care 2001; 16:17-23. [PMID: 11230720 DOI: 10.1053/jcrc.2001.21792] [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: 11/11/2022]
Abstract
PURPOSE The purpose of this article is to elucidate the effect of L-canavanine, a selective inhibitor of inducible NO synthase (iNOS), on hemodynamics, blood gas parameters, and plasma concentrations of lactate and endothelin-1 (ET-1) during endotoxic shock. MATERIALS AND METHODS Eleven mongrel dogs under pentobarbital anesthesia were divided into two groups: (1) bacterial lipopolysaccharide (LPS) plus vehicle group (n = 5) receiving infusion of LPS (3 mg/kg/h for 1 h) followed by vehicle (2 mL/h for 5 hours); (2) LPS plus L-canavanine group (n = 6) receiving infusion of LPS (3 mg/kg/h for 1 hour) followed by L-canavanine (10 mg/kg/h for 5 hours). RESULTS LPS caused a significant (P < .05) decrease in mean arterial pressure (MAP) at 1 hour, but there was no significant difference in MAP during 6-hour period between the two groups. LPS alone did not cause significant changes in other hemodynamics, whereas L-canavanine caused a significant (P < .05) increase in pulmonary vascular resistance index (PVRI) and a decrease in oxygen delivery at 6 hours. The LPS-induced lactic acidosis and hypersecretion of ET-1 were aggravated after L-canavanine infusion. Plasma ET-1 showed positive correlations to lactate levels and PVRI, and negative correlations to cardiac output and oxygen delivery only in the LPS plus L-canavanine group, but not in the LPS plus vehicle group. CONCLUSIONS This study suggests that L-canavanine induces tissue hypoperfusion and ischemia with concomitant hypersecretion of ET-1 in dogs with endotoxic shock.
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Affiliation(s)
- C Mitaka
- Department of Critical Care Medicine, Tokyo Medical and Dental University, Japan
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Abstract
Although significant progress has been made in the treatment of patients with acute lung failure in the critical care setting, the mortality rate from acute lung injury and ARDS is unacceptably high, given the numbers of patients treated for these syndromes each year. The improved understanding of the pathophysiology of respiratory failure from basic science and clinical research is reflected in improved survival rates over the years. Advances in the mechanical ventilator (through microprocessor technology); biosurface technology; liquid ventilation; and, in some cases, returning to so-called "antiquated" practices of patient care (e.g., prone positioning) seem to have had an impact nonetheless. As refinement continues to occur in these areas, morbidity and mortality from lung failure will have a lesser impact on patients as physicians treat the consequences of organ failure in the ICU.
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Affiliation(s)
- M B Shapiro
- Department of Surgery, University of Pennsylvania Health System, Philadelphia, USA
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Abstract
Despite our increased understanding of the biochemistry and physiology of sepsis, the treatment of septic shock remains a challenge. Initial management of septic shock entails urgent and emergent stabilization of the patient followed by broad-spectrum, empiric antibiotic therapy. After volume resuscitation, vasopressors or inotropic therapy or both may be necessary to restore perfusion. Adjunctive therapies and monitoring strategies may be helpful in preventing complications in the intensive care setting. Additional research and clinical trials are needed to identify supportive interventions that may affect the outcome of the septic patient.
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Affiliation(s)
- N Jindal
- Department of Medicine, Rush Medical College, Chicago, Illinois, USA
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Affiliation(s)
- P T Murray
- Department of Anesthesia and Critical Care, University of Chicago, Illinois 60637, USA.
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Abstract
In sepsis and septic shock, inflammatory mediators result in the production of increased concentrations of nitric oxide (NO) from the enzymatic breakdown of the amino acid L-arginine. The increased amounts of NO are responsible for changes in vasomotor tone, decreased vasopressor responsiveness, and decreased myocardial function, characteristic of septic insult. Therapeutic strategies designed to reduce the concentration of NO by inhibiting the action of the nitric oxide synthase enzyme, or by scavenging the excess NO, offer the potential to treat directly the vasomotor abnormalities and myocardial depression seen in sepsis and other inflammatory states. This article reviews the biology of NO in sepsis and discusses strategies for neutralization of the increased NO production, in the setting of severe sepsis and septic shock.
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Affiliation(s)
- S Symeonides
- Section of Critical Care Medicine, Rush Medical College and, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois, USA
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Cobb JP. Use of nitric oxide synthase inhibitors to treat septic shock: the light has changed from yellow to red. Crit Care Med 1999; 27:855-6. [PMID: 10362394 DOI: 10.1097/00003246-199905000-00002] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Practice parameters for hemodynamic support of sepsis in adult patients in sepsis. Task Force of the American College of Critical Care Medicine, Society of Critical Care Medicine. Crit Care Med 1999; 27:639-60. [PMID: 10199548 DOI: 10.1097/00003246-199903000-00049] [Citation(s) in RCA: 244] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To present guidelines for hemodynamic support of adult patients with sepsis. PARTICIPANTS An international task force of nine experts in disciplines related to critical care medicine was convened from the membership of the Society of Critical Care Medicine. EVIDENCE Review of published literature and expertise and personal experience of task force. The strength of evidence of human studies was classified according to study design and scientific value. CONSENSUS PROCESS The task force met several times in person and communicated by electronic mail to identify the pertinent literature and arrive at consensus recommendations. Consideration was given to the relationship between the weight of scientific evidence and the experts'opinions. Draft documents were composed and debated by the task force until consensus was reached. The strength of recommendations was graded according to evidenced-based guidelines. CONCLUSIONS The panel formulated an underlying approach to the hemodynamic support of sepsis. Hemodynamic therapies should be titrated to specific and definable endpoints. The effects of therapy should be assessed by monitoring a combination of parameters of global and regional perfusion. Using this approach, the panel made specific recommendations for fluid resuscitation, vasopressor therapy, and inotropic therapy of septic patients.
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Freeman BD, Cobb JP. Nitric oxide synthase as a therapeutic target in sepsis--more questions than answers? Crit Care Med 1998; 26:1469-70. [PMID: 9751571 DOI: 10.1097/00003246-199809000-00001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Hollenberg SM. A yellow light for nitric oxide synthase inhibitors in sepsis: proceed with caution. Crit Care Med 1998; 26:815-6. [PMID: 9590305 DOI: 10.1097/00003246-199805000-00005] [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: 02/07/2023]
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