Adequate Tissue Perfusion Research Articles

Arginine-Vasopressin in severe septic vs. non-septic shock in extremely low birth weight infants with acute renal failure

Background: Recent clinical investigations have demonstrated that arginine-vasopressin (AVP) may be a valuable alternative or adjunct to common pressor agents in various forms of shock (1, 2). Although, typically septic shock is characterized by AVP deficiency and pressor hypersensitivity to the exogenous hormone, AVP has also been successfully employed in other shock forms that are usually not characterised by AVP deficiency. Aim: To assess the efficacy of AVP as a pressor adjunct to norepinephrine and epinephrine in severe septic vs. non-septic shock in extremely low birth weight infants (ELBW) with acute renal failure (urine output: <0.5ml/kg/h). Patients and Methods: Assessment of AVP therapy as a rescue therapy in three ELBW infants (mean birth weight: 600±30 grams) with severe septic shock and acute renal failure and three ELBW infants (mean birth weight: 770±110grams) with severe non-septic shock and acute renal failure. Main outcome measure was restoration of mean arterial blood pressure (MAP) with reversal of acute renal failure, and survival at discharge. Results: In the group with severe septic shock two hours after starting AVP (dosage:0.04–0.4 U/kg/h) a rise in MAP from 31.7±9.5 to 39.7±19.1mmHg was seen; urine output increased to 9.7±11.5ml/h, and a slight decrease in serum lactate from 9.6±6.7 mmol/l to 8.9±6.2 was noticed. In the group with severe non-septic shock, MAP increased from 25±5 to 38.7±8.3mmHg within 2h of AVP medication (dosage: 0.04–0.4U/kg/h); urine output increased to 5.4±3.2ml/h. Serum lactate moderately increased from 14.3±5.1 to 15.2±6.2 mmol/l. In the non-septic group cardiac and renal changes were only transient and did not impact on the poor prognosis. Mortality rate was 1/3 in the sepsis group vs. 3/3 in the non-septic group. Conclusion: This is the first report on AVP in severe hypotensive shock in ELBW infants. AVP appears to be effective in restoring MAP and subsequent reversal of acute renal failure. Maintenance of adequate and sustained tissue perfusion appears to be dependent on the underlying cause of hypotension. Although AVP seems to be an effective rescue therapy in severe septic shock in ELBW infants further evaluation in controlled clinical trials is warranted.

Transmetatarsal amputation: assessment of current selection criteria

Background Transmetatarsal amputation (TMA) is an operation designed to remove a limited area of irremediable tissue ischemia and/or infection and preserve limb function. Patients are selected for TMA based on degree of tissue loss/infection, adequacy of tissue perfusion at the transmetatarsal level, current ambulatory status, and estimation of the likelihood of postprocedure ambulation. The purpose of this study was to assess the validity of these selection criteria. Methods An institutional review board–approved retrospective review was conducted of all patients undergoing TMA from January 1, 1997, until January 1, 2006. Information was collected on patient demographics, medical comorbidity, and clinical and surgical variables. Outcome measures included the proportion of patients requiring amputation revision to a more proximal level and ambulatory status at last follow-up. Results Fifty-two TMAs were performed. In 35 procedures, the skin was left open, and in 17 TMA was closed primarily. Primary indications for the procedure were vascular insufficiency or infection in 50 of 52 patients, whereas 2 patients required amputation for malignancy. The majority (46/52, 89%) of patients were diabetic. After the index TMA, 85 additional operations were required. Only 9 patients (18%) underwent a single operation. Revision of the TMA to a more proximal level was required in 29 of 52 (56%) patients, resulting in 4 Syme, 20 transtibial, and 5 transfemoral amputations. Non–insulin-dependent diabetes was associated with an increased likelihood of revision to a more proximal amputation (odds ratio [OR] = 5.4; 95% confidence interval [CI], 1.2–24). At the time of last follow-up (median 18 months), 37 of 50 (74%) patients were ambulatory (83% for TMAs and 67% for more proximal amputations, P = 0.18). Prior vascular procedures were associated with a significantly decreased likelihood of ambulation (OR = 14; 95% CI, 1.9–103). Conclusions Although most patients retain the ability to ambulate after TMA, multiple operations should be anticipated in the majority of patients and revision of a TMA to a more proximal level may be required. These data suggest that current selection criteria for TMA may be inadequate.

Endpoints of Resuscitation

Major resuscitation goals in the management of shock include restoration of adequate tissue perfusion and oxygen balance and normalization of cellular metabolism. Identification of the most appropriate endpoints of resuscitation is difficult and often debated in the literature. Traditional endpoints, such as heart rate, blood pressure, mental status, and urine output are useful in the initial identification of inadequate perfusion, but are limited in their ability to identify ongoing, compensated shock. Many clinicians continue to use these parameters as indicators that systemic oxygenation imbalances have resolved, even though they have been found to be poor indicators of ongoing tissue hypoxia. Additional resuscitation endpoints that more closely evaluate the adequacy of perfusion and oxygenation at the tissue level should also be used when managing the critically ill. Selected endpoints should include a variety of global and regional indicators to guide and evaluate the effectiveness of treatment.

Massive transfusion and coagulopathy: pathophysiology and implications for clinical management

To review the pathophysiology of coagulopathy in massively transfused, adult and previously hemostatically competent patients in both elective surgical and trauma settings, and to recommend the most appropriate treatment strategies.Medline was searched for articles on "massive transfusion," "transfusion," "trauma," "surgery," "coagulopathy" and "hemostatic defects." A group of experts reviewed the findings.Coagulopathy will result from hemodilution, hypothermia, the use of fractionated blood products and disseminated intravascular coagulation. The clinical significance of the effects of hydroxyethyl starch solutions on hemostasis remains unclear. Maintaining a normal body temperature is a first-line, effective strategy to improve hemostasis during massive transfusion. Red cells play an important role in coagulation and hematocrits higher than 30% may be required to sustain hemostasis. In elective surgery patients, a decrease in fibrinogen concentration is observed initially while thrombocytopenia is a late occurrence. In trauma patients, tissue trauma, shock, tissue anoxia and hypothermia contribute to the development of disseminated intravascular coagulation and microvascular bleeding. The use of platelets and/or fresh frozen plasma should depend on clinical judgment as well as the results of coagulation testing and should be used mainly to treat a clinical coagulopathy.Coagulopathy associated with massive transfusion remains an important clinical problem. It is an intricate, multifactorial and multicellular event. Treatment strategies include the maintenance of adequate tissue perfusion, the correction of hypothermia and anemia, and the use of hemostatic blood products to correct microvascular bleeding.

Consenso brasileiro de monitorização e suporte hemodinâmico - Parte V: suporte hemodinâmico

Shock occurs when the circulatory system cannot maintain adequate cellular perfusion. If this condition is not reverted irreversible cellular injury establishes. Shock treatment has as its initial priority the fast and vigorous correction of mean arterial pressure and cardiac output to maintain life and avoid or lessen organic dysfunctions. Fluid challenge and vasoactive drugs are necessary to warrant an adequate tissue perfusion and maintenance of function of different organs and systems, always guided by cardiovascular monitorization. The recommendations built in this consensus are aimed to guide hemodynamic support needed to maintain adequate tisular perfusion. Modified Delphi methodology was used to create and quantify the consensus between the participants. AMIB indicated a coordinator who invited more six experts in the area of monitoring and hemodynamic support to constitute the Consensus Advisory Board. Twenty five physician and two nurses selected from different regions of the country completed the expert panel, which reviewed the pertinent bibliography listed at the MEDLINE in the period from 1996 to 2004. Recommendations were made answering 17 questions about hemodynamic support with focus on fluid challenge, red blood cell transfusions, vasoactive drugs and perioperative hemodynamic optimization. Hemodynamic monitoring by itself does not reduce the mortality of critically ill patients, however, we believe that the correct interpretation of the data obtained by the hemodynamic monitoring and the use of hemodynamic support protocols based on well defined tissue perfusion goals can improve the outcome of these patients.

Airway management after major trauma

The primary goal in the early management of the severely-injured patient is the provision of sufficient oxygen to the tissues to avoid organ failure and secondary central nervous system damage. The first priority is to establish and maintain a patent airway. With the addition of high-concentration oxygen and the presence of adequate tissue perfusion, this will enable sufficient spontaneous breathing or assisted ventilation to oxygenate the patient. The possibility of an unstable cervical injury exists in patients exposed to significant blunt trauma; during airway interventions, neck movement must be minimized to avoid secondary harm to the spinal cord. Depending on the series, 2–12% of major trauma victims have a cervical spine injury and 7–14% of these are unstable. Approximately 10% of comatose trauma patients have a cervical spine injury. Head injury with impaired consciousness and reduced pharyngeal tone is the commonest trauma-related cause of airway obstruction. The airway may also be soiled with blood or regurgitated matter. Blunt or penetrating injuries that obstruct the airway include maxillary, mandibular and laryngotracheal fractures, and large anterior neck haematomas. Significant partial and incipient airway obstruction are also potential causes of early death. Vigilant reassessment with immediate restoration and protection of airway patency is essential.

Considerations in Prevention of Surgical Site Infections Following Cardiac Surgery

The incidence of surgical site infections among patients with diabetes continues to occur at a greater rate when compared with their nondiabetic counterparts. Preexisting vascular changes, delayed wound healing, and impaired immune factors contribute. Adult patients with diabetes likely possess comorbid coronary artery disease, thus increasing the need for cardiac surgery. The resultant potential for infection can be combated with supplementary interventions above those universally taken. Modifiable risk factors of hyperglycemia and obesity are targeted preoperatively. Glycemic control, adequate tissue perfusion, and adjunct use of nasal mupirocin are addressed intraoperatively. Lastly, focus is placed on nutrition, exercise, and continued glucose control postoperatively and beyond discharge.

1262: Dynamic tissue perfusion measurement—basics and application in renal diseases

An adequate tissue perfusion is necessary for the normal function of an organ. Changes of perfusion mirror many relevant pathophysiological situations. Increased perfusion is a hallmark of inflammation and also observed in functional adaptation. Decreased perfusion accompanies organ insufficiency, arterial stenosis, congestion and microvascular diseases. Tumors may show a disturbed perfusion pattern and increased or decreased perfusion intensity. We developed a novel technique, the PixelFlux method, to quantify tissue perfusion by a dynamic evaluation of color Doppler signals.

Sestamibi single photon emission computed tomography immediately after primary percutaneous coronary intervention identifies patients at risk for large infarcts

Primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction results in TIMI 3 flow in most patients. However, despite TIMI 3 flow, some patients do not achieve adequate tissue perfusion and have large infarctions. Techniques that, in the acute setting, could identify these patients at increased risk would potentially enable specific interventions to enhance perfusion. The object of the present study was to test whether corrected TIMI frame count (CTFC), myocardial blush grade (MBG), ST-segment resolution, and myocardial perfusion imaging (MPI) can identify those patients who, despite successful treatment with primary PCI for ST-elevation myocardial infarction, are at risk for large infarcts. In 61 patients with TIMI 3 flow after primary PCI, CTFC, MBG, ST-segment resolution, and quantitative MPI by technetium Tc 99m sestamibi single photon emission computed tomography were estimated immediately after primary PCI. Infarct size was assessed by peak lactate dehydrogenase (LDH) and by MPI after 3 months. Infarct size by MPI was 12% (4, 23), and peak LDH was 1410 U/L (870, 2220); these measures correlated (rho = 0.80, P < .001). The acute perfusion defect predicted infarct size using either method (MPI rho = 0.88, P < .001; LDH rho = 0.77, P < .001); ST-segment residual correlated weakly to infarct size, whereas CTFC and MBG did not. In multivariate analysis, the acute perfusion defect was the only significant predictor of infarct size. Myocardial perfusion imaging performed immediately after successful PCI can identify patients at increased risk for large infarcts due to impaired tissue perfusion. Acute MPI might serve as a tool for early identification of patients, who, despite epicardial TIMI 3 flow, have inadequate tissue level perfusion.

Summary Proceedings From the Cardiology Group on Cardiovascular Instability in Preterm Infants

The appropriate determination of adequate tissue perfusion and the best approach to treatment of perceived abnormalities in blood pressure in the neonate remain controversial. There is no consensus regarding the actual definition of hypotension in the neonate or how best to raise perceived low blood pressure. In addition, there is no direct and prospectively collected information available on the result of treatment of a "low" blood pressure on neonatal morbidity and mortality. It also has not been clearly demonstrated that bringing systemic blood pressure to a "normal" range improve outcomes. However, it is widely accepted by clinicians that early and aggressive treatment of hypotension leads to improved neurologic outcome and survival in the neonate. Commonly used therapeutic maneuvers to correct systemic hypotension in the neonate include volume expansion, inotropic agents, and corticosteroids. Although there is a paucity of research on the cardiovascular response to these commonly used agents in neonates, among the commonly used inotropic drugs dopamine has been shown to be more effective than dobutamine in raising blood pressure in the neonate. The cardiology group focused on the use of inotropes, particularly dopamine and dobutamine, to treat very low birth weight infants with cardiac instability and neonatal postoperative cardiac patients. The cardiology group identified key issues that must be considered when designing studies of inotropic agents in preterm infants and proposed 2 clinical-trial designs: (1) a placebo-controlled trial with rescue for symptomatic infants; and (2) a targeted-blood pressure study. The first trial design would answer questions concerning efficacy of treatment with inotropic agents in this population. The second trial design would address concerns related to the lack of knowledge on normal blood pressure ranges in this population. The group identified specific design elements that would need to be addressed for the complicated trial design to study inotropic agents in neonates.

Hemorrhagic shock in obstetrics

Acute postpartum hemorrhage is the leading worldwide cause of maternal mortality, such deaths being usually related to the development of hemorrhagic shock and its consequences, especially the multiple organ dysfunction syndrome. Obstetricians should be aware of the clinical manifestations and principles of management of hemorrhagic shock. Initial assessment of the bleeding patient requires monitoring blood pressure, pulse, capillary refill, mental status and urinary output. This allows estimation of the amount and the rate of blood loss and helps direct treatment. Hemorrhagic shock is a condition in which inadequate perfusion of organs results in insufficient availability of oxygen to satisfy the metabolic needs of the tissues. A catabolic state develops. The consequences of these changes are inflammation, endothelial dysfunction, and disruption of normal metabolic processes in vital organs. Once these events become established, the process of shock is often irreversible, even if volume and red cell deficits are corrected. The principal goals of management are controlling the source of the blood loss; restoring adequate oxygen carrying capacity; and maintaining adequate tissue perfusion. Patients with severe postpartum hemorrhage are at risk of developing hypothermia, an insidious complication that contributes substantially to morbidity and mortality. It must be prevented or treated promptly. Successful treatment of exsanguinating postpartum hemorrhage depends on efficient collaboration among all members of the patient care team, and a management plan based on an understanding of the pathophysiology of shock and tailored to the individual patient's situation.

82 A Low Mean Blood Pressure in Extremely Low Birth Weight Infants in the First Week is not a Risk Factor for Neurodevelopmental Problems at Age 2 Years

Background: Hypotension may cause poor perfusion and ischaemia. It is not known what BP is too low to maintain adequate tissue perfusion. We have previously measured the distribution of BP in a database of 1230 infants (238 <1000g) over the first week of life. We examined whether a low mean blood pressure (mBP) in extremely low birth weight (ELBW), (<1000g) was associated with later abnormal neurodevelopment.Methods: From 9/1997 to 10/2002, all ELBW infants were included who had continuous intravascular BP measurements. For each infant, each 6 hr period over the first 7 days of life was given a z score related to the total population. Small for gestational age (SGA) infants (n=32) and infants with >50% missing data (n=23) were excluded. The neurodevelopment (motor and communication skills, hearing, vision and overall development) of surviving infants was scored at two years corrected age - normal 1, mild problems 2, moderate 3, severe 4, dead 5. Severity of disability was plotted against the mBP Z-score and the Kruskal-Wallis test was used to compare groups.Results: Data were available for 62 infants - gestation 25.2 weeks (SD 1.30) birthweight 756g (SD 140), 37 were male, 36 received inotropes. 18 died, and 4 were lost to follow up. At 2 year follow up, 15 (38%) had developmental delay, 9 (23%) motor and 17 (43%)communication difficulties, 11 (28%) visual and 2 (5%) hearing problems. There was no significant relationship between the mBP in the first week and the presence or degree of any neurodevelopmental parameter at the age of 2 years.Conclusion: In this series we could define no relationship between mBP in the first week of life and neurodevelopmental outcome at 2 years of age.

HIGH-DOSE VITAMIN C INFUSION REDUCES FLUID REQUIREMENTS IN THE RESUSCITATION OF BURN-INJURED SHEEP

Fluid resuscitation to maintain adequate tissue perfusion while reducing edema in the severely burned patient remains a challenge. Recent studies suggest that reactive oxygen species generated by thermal injury are involved in edema formation associated with burn. The present study tested the hypothesis that adding a free radical scavenger to the resuscitation fluid would reduce total fluid requirements in the treatment of severe thermal injury. Anesthetized chronically instrumented sheep received a 40% total body surface area full-thickness flame burn. At 1 h after injury, animals were resuscitated with lactated Ringer's (LR, n = 14) as control, LR containing high doses of vitamin C (VC, n = 6), 1000 mOsM hypertonic saline (HS, n = 7), or 1000 HS containing VC (HS/VC, n = 7) in coded bags so that investigators were blinded to the treatment. Fluids were infused at an initial Parkland rate of 10 mL/kg/h, adjusted hourly to restore and maintain urine output at 1 to 2 mL/kg/h. Sheep in the VC or HS/VC group received 250 mg/kg VC in the first 500 mL of LR or HS, and then 15 mg/kg/h thereafter. Hemodynamic variables and indices of antioxidant status were measured. At 48 h postburn, sheep were euthanized, and heart, liver, lung, skeletal muscle, and ileum were evaluated for antioxidant status. All fluid resuscitation regimens were equally effective in restoring cardiac output to near baseline levels; no treatment effects were apparent on arterial pressure or heart rate. VC infusion significantly reduced fluid requirements and, therefore, net fluid balance (fluid in, urine out) by about 30% at 6 h and about 50% at 48 h in comparison with the LR group (P < 0.05). HS and HS/VC reduced fluid requirements by 30% and 65%, respectively, at 6 h, but the volume-sparing effect of HS was not observed after 36 h and that of HS/VC was lost after 12 h. Plasma total antioxidant potential increased about 25-fold (P < 0.05) at 2 and 3 h in response to VC infusion compared with the LR and HS groups, and remained about 5- to 10-fold higher throughout the rest of the study. VC infusion also prevented the 4-fold increase in plasma thiobarbituric acid reactive substances seen in the LR group early after burn (P < 0.05). Tissue antioxidant status was similar between groups. In this sheep burn model, continuous high-dose VC infusion reduced net fluid balance, reduced indices of plasma lipid peroxidation, and maintained overall antioxidant status in comparison with standard-of-care LR treatment.

Sepsis and Myocardial Depression in a Young Woman

Severe sepsis may be associated with depression of myocardial function, attributed to various inflammatory mediators. Myocardial dysfunction in sepsis is characterized by biventricular failure and complicates usual therapy with high-volume fluid resuscitation and vasopressors. However, in patients who survive septic shock, myocardial dysfunction can improve rapidly. We describe a young woman with septic shock due to Streptococcus pneumoniae, complicated by severe but reversible biventricular dysfunction.

Therapie des Organversagens bei prim�r extrakardialen Erkrankungen

There are a number of primary extracardiac circulatory disorders leading to organ dysfunction, multi-organ dysfunction syndrome and finally to multi-organ-failure. The origin of this hemodynamic disturbances are potentially different forms of circulatory shock (septic, hypovolemic, anaphylactic or neurogenic shock) and the systemic inflammatory reaction syndrome (SIRS). The primary aim of therapy is the removal of the underlying causes and the restoration of adequate tissue perfusion by using fluids, vasopressors and inotropics. The supportive treatment of the individual organ dysfunction is - at present - unequally efficient.

The Impact of Heparin Coated Circuits Upon Metabolism in Vital Organs: Effect Upon Cerebral and Renal Function During and After Cardiopulmonary Bypass

During cardiopulmonary bypass (CPB), the brain and the kidneys may be damaged because of microemboli, ischemia, and inflammation. The latter has been reduced by the use of heparin coated circuits. We questioned whether heparin coated circuits could also reduce cerebral and renal damage and whether inflammatory markers correlate with damage to the brain and the kidneys. Fifty-one patients scheduled for coronary artery bypass grafting were perfused with either a heparin coated or an uncoated circuit. To compare the effect of a heparin coated circuit with an uncoated circuit upon cerebral and renal function in relation to inflammation, we assessed markers of cerebral (S100beta) and renal (N-acetyl-beta-D-glucosaminidase [NAG], creatinine, and urea) function, inflammation, and oxygen metabolism. S100beta levels and NAG levels increased during CPB in both groups as compared with baseline levels (p < 0.01), without differences between the groups. After 15 minutes on CPB, C4b/c levels were significantly higher in the coated group compared with the uncoated group (p < 0.02). C4b/c correlated with S100beta (p < 0.01). Total body oxygen delivery (DO2) and consumption (VO2) decreased significantly in both groups during CPB (p < 0.01), but recovery was better in the coated group. After protamine infusion, total body oxygen delivery and consumption correlated negatively with S100beta levels (both p < 0.05) and with NAG levels (both p < 0.01). This study suggests that, if adequate tissue perfusion is not maintained, the use of a heparin coated circuit gives no additional benefit beyond that of the uncoated circuit. The inverse relationship of both cerebral and renal markers with DO2 and VO2 suggests that increased levels of S100beta and NAG during CPB may primarily be caused by an oxygen deficit and secondary to the inflammatory response.

Transfusion massive et dysfonction hémostatique : physiopathologie et gestion clinique

Purpose. – To identify the causes of coagulopathy in massively transfused adults and previously hemostatically competent patients, and to recommend the most appropriate treatment strategies. Principal findings. – In trauma patients, tissue trauma, shock, tissue anoxia and hypothermia contribute to the development of disseminated intravascular coagulation and microvascular bleeding. In elective surgery patients, a decrease in fibrinogen concentration is observed initially while thrombocytopenia is a late occurrence. Critically low levels of coagulation factors were seldom reported when whole blood was in common use. With the use of packed red cells, dilution or consumption of coagulation factors is a significant issue requiring specific treatment with primarily, fresh frozen plasma. Maintaining a normal body temperature is a simple and effective strategy to improve hemostasis during massive transfusion. Red cells play an important role and hematocrits as high as 35% may be required to sustain hemostasis. The use of platelets and/or fresh frozen plasma should depend on clinical judgment and results of coagulation testing and should be used mainly to treat a clinical coagulopathy. Conclusions. – Coagulopathy associated with massive transfusion remains an important problem. Treatment strategies include the maintenance of adequate tissue perfusion, the correction of hypothermia and anemia, and the use of hemostatic blood products to correct microvascular bleeding.

Recombinant human erythropoietin stimulates angiogenesis and healing of ischemic skin wounds.

Wound healing in ischemic tissues such as flap margins due to inadequate blood supply is still a source of considerable morbidity in surgical practice. Adequate tissue perfusion is particularly important in wound healing. We investigated the effects of recombinant human erythropoietin (rHuEPO) on wound healing in an ischemic skin wound model. Sixty-three Sprague-Dawley rats were used. Normal incisional wound and H-shaped double flaps were used as the wound models. Animals were treated with rHuEPO (400 IU/kg) or its vehicle. Rats were killed on different days (3, 5, and 10 days after skin injury) and the wounded skin tissues were used for immunohistochemistry and for analysis of vascular endothelial growth factor content and collagen content. Tissue transglutaminase immunostaining of histological specimens was used as a vascular marker to determine the level of microvessel density. The results showed a higher level of vascular endothelial growth factor protein and an increased microvessel density in ischemic wounds with rHuEPO treatment than the normal incisional wounds and ischemic control wounds. Collagen content was higher in the incisional wounds and in the ischemic wounds with rHuEPO treatment compared with the ischemic control wounds. Our results suggest that erythropoietin may be an effective therapeutic approach in improving healing in ischemic skin wounds.

Massive transfusion and coagulopathy: pathophysiology and implications for clinical management.

To review the pathophysiology of coagulopathy in massively transfused, adult and previously hemostatically competent patients in both elective surgical and trauma settings, and to recommend the most appropriate treatment strategies. Medline was searched for articles on "massive transfusion," "transfusion," "trauma," "surgery," "coagulopathy" and "hemostatic defects." A group of experts reviewed the findings. Coagulopathy will result from hemodilution, hypothermia, the use of fractionated blood products and disseminated intravascular coagulation. The clinical significance of the effects of hydroxyethyl starch solutions on hemostasis remains unclear. Maintaining a normal body temperature is a first-line, effective strategy to improve hemostasis during massive transfusion. Red cells play an important role in coagulation and hematocrits higher than 30% may be required to sustain hemostasis. In elective surgery patients, a decrease in fibrinogen concentration is observed initially while thrombocytopenia is a late occurrence. In trauma patients, tissue trauma, shock, tissue anoxia and hypothermia contribute to the development of disseminated intravascular coagulation and microvascular bleeding. The use of platelets and/or fresh frozen plasma should depend on clinical judgment as well as the results of coagulation testing and should be used mainly to treat a clinical coagulopathy. Coagulopathy associated with massive transfusion remains an important clinical problem. It is an intricate, multifactorial and multicellular event. Treatment strategies include the maintenance of adequate tissue perfusion, the correction of hypothermia and anemia, and the use of hemostatic blood products to correct microvascular bleeding.

Patients in circulatory shock in emergency and intensive care units

Patients in circulatory shock are being treated in emergency as well as in intensive care units. Despite different resources in personnel and technical equipment in both areas, patient management has to follow standardized protocols. Diagnosis of shock has to be based upon objective parameters (lactate, pH, standard bicarbonate, arterial blood pressure, central venous pressure, cardiac output). Aim of shock treatment is restoration of adequate tissue perfusion with the use of fluid and red blood cell replacement, vasoconstrictors, inotropics, substances improving microcirculation, and mechanical circulatory support. Target values are: mean arterial blood pressure >80 mmHg, central venous pressure >6 mmHg, hemoglobin >8.0 g/dl, cardiac index >3.5 l/min/m(2). New concepts for optimization of hemodynamics and hematocrit, cortisone, intraaortic balloon counterpulsation, mechanical ventilation with low tidal volumes, and intensive insulin therapy are discussed. However, as shock reversal is dependent on its reason, clarification and treatment of the shock causing event has to be performed with highest priority.