Strong vasopressor support may be futile in the intensive care unit patient with multiple organ failure

Effect of early vasopressin combined with norepinephrine on short-term mortality in septic shock: A retrospective study based on the MIMIC-IV database

BACKGROUND

Septic shock is a leading cause of death in intensive care units (ICUs), with short-term mortality rates of 35-40%. Vasopressin (AVP) is a second-line vasoactive agent for septic shock, and recent studies suggest that early AVP use can be beneficial. However, differences between early initiation of AVP combined with norepinephrine (NE) and nonearly AVP with NE are unclear. A retrospective cohort research was designed to explore the effects of early AVP initiation versus nonearly AVP initiation.

METHODS

This retrospective single-center cohort study included adult patients with septic shock from the MIMIC (Medical Information Mart for Intensive Care)-IV database. According to whether AVP was used early in the ICU (intensive care unit), patients were assigned to the early- (within 6 h of septic shock onset) and non-early-AVP (at least 6 h after septic shock onset) groups. The primary outcome was 28-day mortality. The secondary outcomes were ICU and hospital mortality, the numbers of vasopressor-free and ventilation-free days at 28 days, ICU length of stay (LOS), hospital LOS, sequential organ failure assessment (SOFA) score on days 2 and 3, and renal replacement therapy (RRT) use on days 2 and 3. Univariate and multivariate cox proportional-hazards regression, propensity-score matching were used to analyze the differences between the groups.

RESULTS

The study included 531 patients with septic shock: 331 (62.5%) in the early-AVP group and 200 (37.5%) in the non-early-AVP group. For 1:1 matching, 158 patients in the early-AVP group were matched with the same number of patients with nonearly AVP. Regarding the primary outcome, there was no significant difference between the early- and non-early-AVP groups in 28-day mortality (hazard ratio [HR] = 0.91, 95% confidence interval [CI] = 0.68-1.24). For the secondary outcomes, there were no differences between the early- and non-early-AVP groups in ICU mortality (HR = 0.95, 95% CI = 0.67-1.35), hospital mortality (HR = 0.95, 95% CI = 0.69-1.31), the numbers of vasopressor-free and ventilation-free days at 28 days, ICU LOS, hospital LOS, SOFA score on days 2 and 3, and RRT use on days 2 and 3.

CONCLUSIONS

There was no difference in short-term mortality between early AVP combined with NE and nonearly AVP with NE in septic shock.

Resuscitative Effect of Centhaquine (Lyfaquin®) in Hypovolemic Shock Patients: A Randomized, Multicentric, Controlled Trial

INTRODUCTION

Centhaquine (Lyfaquin®) showed significant efficacy as a resuscitative agent in animal models of haemorrhagic shock. Its safety and tolerability were confirmed in healthy human volunteers. In this study, our primary objective was to determine the safety, and the secondary objective was to assess the efficacy of centhaquine in patients with hypovolemic shock.

METHODS

A prospective, multicentre, randomized phase II study was conducted in male and female patients aged 18-70 years with hypovolemic shock having systolic BP ≤ 90 mmHg. Patients were randomized in a 1:1 ratio to either the control or centhaquine group. The control group received 100 ml of normal saline infusion over 1 h, while the centhaquine group received 0.01 mg/kg of centhaquine in 100 ml normal saline infusion over 1 h. Every patient received standard of care (SOC) and was followed for 28 days.

RESULTS

Fifty patients were included, and 45 completed the trial: 22 in the control group and 23 in the centhaquine group. The demographics of patients in both groups were comparable. No adverse event related to centhaquine was recorded in the 28-day observation period. The baseline, Injury Scoring System score, haemoglobin, and haematocrit were similar in both groups. However, 91% of the patients in the centhaquine group needed major surgery, whereas only 68% in the control group (p = 0.0526). Twenty-eight-day all-cause mortality was 0/23 in the centhaquine group and 2/22 in the control group. The percent time in ICU and ventilator support was less in the centhaquine group than in the control group. The total amount of vasopressors needed in the first 48 h of resuscitation was lower in the centhaquine group than in the control group (3.12 ± 2.18 vs. 9.39 ± 4.28 mg). An increase in systolic and diastolic BP from baseline through 48 h was more marked in the centhaquine group than in the control group. Compared with the control group, blood lactate level was lower by 1.75 ± 1.07 mmol/l in the centhaquine group on day 3 of resuscitation. Improvements in base deficit, multiple organ dysfunction syndrome (MODS) score and adult respiratory distress syndrome (ARDS) were greater in the centhaquine group than in the control group.

CONCLUSION

When added to SOC, centhaquine is a well-tolerated and effective resuscitative agent. It improves the clinical outcome of patients with hypovolemic shock.

TRIAL REGISTRATION

ClinicalTrials.gov identifier number: NCT04056065.

A Multicentric, Randomized, Controlled Phase III Study of Centhaquine (Lyfaquin®) as a Resuscitative Agent in Hypovolemic Shock Patients

Introduction

Centhaquine (Lyfaquin^®) showed significant safety and efficacy in preclinical and clinical phase I and II studies.

Methods

A prospective, multicentric, randomized phase III study was conducted in patients with hypovolemic shock, systolic blood pressure (SBP) ≤ 90 mmHg, and blood lactate levels ≥ 2 mmol/L. Patients were randomized in a 2:1 ratio to the centhaquine group (n = 71) or the control (saline) group (n = 34). Every patient received standard of care (SOC) and was followed for 28 days. The study drug (normal saline or centhaquine 0.01 mg/kg) was administered in 100 mL of normal saline infusion over 1 h. The primary objectives were to determine changes (mean through 48 h) in SBP, diastolic blood pressure (DBP), blood lactate levels, and base deficit. The secondary objectives included the amount of fluids, blood products, and vasopressors administered in the first 48 h, duration of hospital stay, time in intensive care units, time on ventilator support, change in acute respiratory distress syndrome (ARDS), multiple organ dysfunction syndrome (MODS), and the proportion of patients with 28-day all-cause mortality.

Results

The demographics of patients and baseline vitals in both groups were comparable. The cause of hypovolemic shock was trauma in 29.4 and 47.1% of control group and centhaquine group patients, respectively, and gastroenteritis in 44.1 and 29.4%, respectively. Shock index (SI) and quick sequential organ failure assessment at baseline were similar in the two groups. An equal amount of fluids and blood products were administered in both groups during the first 48 h of resuscitation. A lesser amount of vasopressors was needed in the first 48 h of resuscitation in the centhaquine group. An increase in SBP from baseline was consistently higher up to 48 h (12.9% increase in area under the curve from 0 to 48 h [AUC_0–48]) in the centhaquine group than in the control group. A significant increase in pulse pressure (48.1% increase in AUC_0–48) in the centhaquine group compared with the control group suggests improved stroke volume due to centhaquine. The SI was significantly lower in the centhaquine group from 1 h (p = 0.032) to 4 h (p = 0.049) of resuscitation. Resuscitation with centhaquine resulted in a significantly greater number of patients with improved blood lactate (control 46.9%; centhaquine 69.3%; p = 0.03) and the base deficit (control 43.7%; centhaquine 69.8%; p = 0.01) than in the control group. ARDS and MODS improved with centhaquine, and an 8.8% absolute reduction in 28-day all-cause mortality was observed in the centhaquine group.

Conclusion

Centhaquine is an efficacious resuscitative agent for treating hypovolemic shock. The efficacy of centhaquine in distributive shock is being explored.

Trial Registration

Clinical Trials Registry, India; ctri.icmr.org.in, CTRI/2019/01/017196; clinicaltrials.gov, NCT04045327.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40265-021-01547-5.

A multicentric, randomized, controlled phase III study of centhaquine (Lyfaquin ® ) as a resuscitative agent in hypovolemic shock patients

INTRODUCTION

Centhaquine (Lyfaquin ^® ) showed significant safety and efficacy in preclinical and clinical phase I and II studies.

METHODS

A prospective, multicentric, randomized phase III study was conducted in patients with hypovolemic shock having systolic blood pressure (SBP) of ≤90 mm Hg and blood lactate levels of ≥2 mmol/L. Patients were randomized in a 2:1 ratio, 71 patients to the centhaquine group and 34 patients to the control (saline) group. Every patient received standard of care (SOC) and was followed for 28 days. The study drug (normal saline or centhaquine (0.01 mg/kg)) was administered in 100 mL of normal saline infusion over 1 hour. The primary objectives were to determine changes (mean through 48 hours) in SBP, diastolic blood pressure (DBP), blood lactate levels, and base deficit. The secondary objectives included the amount of fluids, blood products, vasopressors administered in the first 48 hours, duration of hospital stay, time in ICU, time on the ventilator support, change in patient's Acute Respiratory Distress Syndrome (ARDS), Multiple Organ Dysfunction Syndrome (MODS) scores, and the proportion of patients with 28-day all-cause mortality.

RESULTS

The demographics of patients and baseline vitals in both groups were comparable. Trauma was the cause of hypovolemic shock in 29.41% of control and 47.06% of centhaquine, gastroenteritis in 44.12% of control, and 29.41% of centhaquine patients. An equal amount of fluids and blood products were administered in both groups during the first 48 hours of resuscitation. A lesser amount of vasopressors was needed in the first 48 hours of resuscitation in the centhaquine group. An increase in SBP from the baseline was consistently higher in the centhaquine group than in the control. A significant increase in pulse pressure in the centhaquine group than the control group suggests improved stroke volume due to centhaquine. The shock index was significantly lower in the centhaquine group than control from 1 hour (p=0.0320) till 4 hours (p=0.0494) of resuscitation. Resuscitation with centhaquine had a significantly greater number of patients with improved blood lactate and the base deficit than the control group. ARDS and MODS improved with centhaquine, and an 8.8% absolute reduction in 28-day all-cause mortality was observed in the centhaquine group.

CONCLUSION

Centhaquine is a highly efficacious resuscitative agent for treating hypovolemic shock. The efficacy of centhaquine in distributive shock due to sepsis and COVID-19 is being explored.

TRIAL REGISTRATION

Clinical Trials Registry, India; ctri.icmr.org.in, CTRI/2019/01/017196; clinicaltrials.gov, NCT04045327 .

KEY SUMMARY POINTS

A multicentric, randomized, controlled trial was conducted to evaluate the efficacy of centhaquine in hypovolemic shock patients.One hundred and five patients were randomized 2:1 to receive centhaquine or saline. Centhaquine was administered at a dose of 0.01 mg/kg in 100 mL saline and infused over 1 hour. The control group received 100 mL of saline over a 1-hour infusion.Centhaquine improved blood pressure, shock index, reduced blood lactate levels, and improved base deficit. Acute Respiratory Distress Syndrome (ARDS) and Multiple Organ Dysfunction Syndrome (MODS) score improved with centhaquine.An 8.8% absolute reduction in 28-day all-cause mortality was observed in the centhaquine group. There were no drug-related adverse events in the study.

Time to vasopressor initiation and organ failure progression in early septic shock

OBJECTIVE

Research evaluating the relationship between vasopressor initiation timing and clinical outcomes is limited and conflicting. We investigated the association between time to vasopressors, worsening organ failure, and mortality in patients with septic shock.

METHODS

This was a retrospective study of patients with septic shock (2013-2016) within 24 hours of emergency department (ED) presentation. The primary outcome was worsening organ failure, defined as an increase in Sequential Organ Failure Assessment (SOFA) score ≥2 at 48 hours compared to baseline, or death within 48 hours. The secondary outcome was 28-day mortality. Time to vasopressor initiation was categorized into 6, 4-hour intervals from time of ED triage. Multiple logistic regression was used to identify predictors of worsening organ failure.

RESULTS

We analyzed data from 428 patients with septic shock. There were 152 patients with the composite primary outcome (SOFA increase ≥2 or death at 48 hours). Of these, 77 patients died in the first 48 hours and 75 patients had a SOFA increase ≥2. Compared to the patients who received vasopressors in the first 4 hours, those with the longest time to vasopressors (20-24 hours) had increased odds of developing worsening organ failure (odds ratios [OR] = 4.34, 95% confidence intervals [CI] = 1.47-12.79, P = 0.008). For all others, the association between vasopressor timing and worsening organ failure was non-significant. There was no association between time to vasopressor initiation and 28-day mortality.

CONCLUSIONS

Increased time to vasopressor initiation is an independent predictor of worsening organ failure for patients with vasopressor initiation delays >20 hours.

Early Use of Norepinephrine Improves Survival in Septic Shock: Earlier than Early

BACKGROUND

The timing of initiation of Norepinephrine (NEP) in septic shock is controversial.

AIM OF THE STUDY

We evaluated the impact of early NEP simultaneously with fluids in those patients.

METHODS

We randomized 101 patients admitted to the emergency department with septic shock to early NEP simultaneously with IV fluids (early group) or after failed fluids trial (late group). The primary outcome was the in-hospital survival while the secondary outcomes were the time to target mean arterial pressure (MAP) of 65 mmHg, lactate clearance and resuscitation volumes.

RESULTS

There was no significant difference between the two groups regarding the baseline characteristics. NEP infusion started after 25 (20-30) and 120 (120-180) min in the early and late groups (p = 0.000). MAP of 65 mmHg was achieved faster in the early group (2 [1-3.5] h vs. 3 [2-4.75] h, p = 0.003). Serum lactate was decreased by 37.8 (24-49%) and 22.2 (3.3-38%) in both groups respectively (p = 0.005). Patients with early NEP were resuscitated by significantly lower volume of fluids (25 [18.8-28.7] mL/kg vs. 32.5 [24.4-34.6] mL/kg) in the early and late groups (p = 0.000). The early group had survival rate of 71.9% compared to 45.5% in the late group (p = 0.007). NEP started after 30 (20-120 min) in survivors vs. 120 (30-165 min) in non-survivors (p = 0.013).

CONCLUSIONS

We concluded that early Norepinephrine in septic shock might cause earlier restoration of blood pressure, better lactate clearance and improve in-hospital survival.

Time-limited trial of intensive care treatment: an overview of current literature

In critically ill patients, it is frequently challenging to identify who will benefit from admission to the intensive care unit and life-sustaining interventions when the chances of a meaningful outcome are unclear. In addition, the acute illness not only affects the patients but also family members or surrogates who often are overwhelmed and unable to make thoughtful decisions. In these circumstances, a time-limited trial (TLT) of intensive care treatment can be helpful. A TLT is an agreement to initiate all necessary treatments or treatments with clearly delineated limitations for a certain period of time to gain a more realistic understanding of the patient's chances of a meaningful recovery or to ascertain the patient's wishes and values. In this article, we discuss current research on different aspects of TLTs in the intensive care unit. We propose how and when to use TLTs, discuss how much time should be taken for a TLT, give an overview of the potential impact of TLTs on healthcare resources, describe ethical challenges concerning TLTs, and discuss how to evaluate a TLT.

Outcome of patients with septic shock and high-dose vasopressor therapy

Background

Despite the dissemination of international guidelines, mortality from septic shock remains high. Norepinephrine is recommended as first-line vasopressor therapy with a target mean arterial pressure of 65 mmHg. High-dose vasopressor (HDV) may also be required. This study aimed to assess survival in patients with septic shock requiring HDV. We conducted a retrospective study of patients admitted between January 2008 and December 2013 to a 13-bed ICU for septic shock and receiving high-dose vasopressor therapy (defined by a dose >1 µg/kg/min). Primary outcome was 28-day mortality (D28). Secondary outcomes were 90-day mortality (D90), organ failure score (SOFA), duration of organ failure, duration and dosage of vasopressor agent and ischemic complications.

Results

In our cohort of 106 patients, mortality reached 60.4% at D28 and 66.3% at D90. One in two patients died before D10. The weight-based mean dose of vasopressor (WMD) represented the best prognostic factor. Using a cutoff of 0.75 µg/kg/min, WMD was associated with mortality with a sensitivity of 73% and specificity of 74%. The mortality rate reached 86.4% when WMD was above the cutoff value and associated with a SOFA score >10. Digital or limb necrosis was documented in 6 patients (5.7%).

Conclusions

In total, 40% of septic shock patients receiving high-dose vasopressor therapy survived at day 28 after admission. A WMD cutoff value of 0.75 µg/kg/min, associated with a >10 SOFA score, was a strong predictor of death. These results provide insights into outcome of refractory septic shock, showing that administration of high-dose vasopressor may indeed be useful in these patients.

Sepsis: Current Definition, Pathophysiology, Diagnosis, and Management

Sepsis is a clinical syndrome that results from the dysregulated inflammatory response to infection that leads to organ dysfunction. The resulting losses to society in terms of financial burden, morbidity, and mortality are enormous. We provide a review of sepsis, its underlying pathophysiology, and guidance for diagnosis and management of this common disease. Current established treatments include appropriate antimicrobial agents to target the underlying infection, optimization of intravascular volume to improve stroke volume, vasopressors to counteract vasoplegic shock, and high-quality supportive care. Appropriate implementation of established treatments combined with novel therapeutic approaches promises to continue to decrease the impact of this disease.

Severe Sepsis and Septic Shock: Timing of Septic Shock Onset Matters

INTRODUCTION

Timing of septic shock onset may play a prognostic role in severe sepsis; however, clinical evidence provides contradictory results. This study aimed to investigate possible associations between timing of onset of septic shock and patient outcome.

METHODS

In a university-affiliated hospital, all patients admitted to the intensive care unit (ICU) for severe sepsis or septic shock from November 2007 to March 2011 were included. The primary outcome of interest was the impact of timing of septic shock onset on in-hospital mortality. We also sought to identify potential factors predicting development of septic shock after ICU admission.

RESULTS

In total, 772 patients were identified to have severe sepsis; approximately two-thirds (487/772) of them experienced septic shock and overall in-hospital mortality was 57%. Timing of onset of septic shock was an independent predictor of in-hospital outcome, and there was an increasing trend of in-hospital mortality with later onset of septic shock. In addition, timing of septic shock onset provided further mortality risk stratification in patients with APACHE II scores of less than 20 and 20 to 25. We also found that patients who underwent cardiovascular surgery were more likely to experience septic shock after admission and those receiving neurosurgery were at lower risk of developing septic shock.

CONCLUSIONS

This study showed the significance of timing of septic shock onset in prognosis among ICU patients with severe sepsis. Timing of shock onset further stratified patients with similar disease severity into different mortality risk groups. These findings deliver useful information regarding risk stratification of septic patients.

Update on Vasopressors and Inotropes in Septic Shock

Vasopressors and inotropes are used in septic shock in patients who remain hypotensive despite adequate fluid resuscitation. The goal is to increase blood pressure to optimize perfusion to organs. Generally, goal-directed therapy to supra-normal oxygen transport variables cannot be recommended due to lack of benefit. Traditionally, vasopressors and inotropes in septic shock have been started in a step-wise fashion starting with dopamine. Recent data suggest that there may be true differences among vasopressors and inotropes on local tissue perfusion as measured by regional hemodynamic and oxygen transport. When started early in septic shock, norepinephrine decreases mortality, optimizes hemodynamic variables, and improves systemic and regional (eg, renal, gastric mucosal, splanchnic) perfusion. Epinephrine causes a greater increase in cardiac index (CI) and oxygen delivery (DO2 ) and increases gastric mucosal flow, but increases lactic acid and may not adequately preserve splanchnic circulation owing to its predominant vasoconstrictive alpha (α ) effects. Epinephrine may be particularly useful when used earlier in the course of septic shock in young patients and those who do not have any known cardiac abnormalities. Unlike epinephrine, dopamine does not preferentially increase the proportion of CI that preferentially goes to the splanchnic circulation. Dopamine is further limited because it cannot increase CI by more than 35% and is accompanied by tachycardia or tachydysrhythmias. Dopamine, as opposed to norepinephrine, may worsen splanchnic oxygen consumption (VO2 ) and oxygen extraction ratio (O2 ER). Low-dose dopamine has not been shown to consistently increase the glomerular filtration rate or prevent renal failure, and, indeed, worsens splanchnic tissue oxygen use. Routine use of concurrently administered dopamine with vasopressors is not recommended. Phenylephrine should be used when a pure vasoconstrictor is desired in patients who may not require or do not tolerate the beta (β ) effects of dopamine or norepinephrine with or without dobutamine. Patients with high filling pressure and hypotension may benefit from the combination of phenylephrine and dobutamine. Investigational approaches to vasopressor-refractory hypotension in septic shock include the use of vasopressin and corticosteroids.

Characteristics of Intensive Care in Patients Hospitalized for Heart Failure in Europe

Patients hospitalized for acute heart failure (AHF) may clinically decompensate and experience life-threatening complications. Regional differences in intensive care unit (ICU) admission rates have been reported by European registries. Variations regarding ICU bed and facilities availability may contribute to these geographic differences. ICU triage decision requires cautious clinical judgment to balance between clinical benefit of ICU care and associated risk and cost. In Europe, despite large variations in treatment practices, in-hospital mortality of AHF patients managed in ICUs is similar, suggesting that high-risk characteristics of AHF patients admitted to ICUs, rather than geographic variation in intensity of therapies, may be the principal determinant of prognosis.

Should the norepinephrine maximal dosage rate be greatly increased in late shock?

Any advanced shock eventually degenerates into vasoplegia, which responds weakly to vasopressors. The highest reported norepinephrine flow rate is 3 μg/kg/min. We present the case of a young explosion victim, who was transferred in late haemorrhagic shock. Apart from usual treatment (hydration, mass transfusion protocol), single-agent norepinephrine was used to maintain a mean arterial pressure (MAP) of >60-65 mm Hg. For several hours, norepinephrine flow was 7-10 times the aforementioned (highest reported) in order to achieve our goal; during which, further hydration or transfusion would not contribute to MAP elevation. Sequential Organ Failure Assessment (SOFA) severity score was 18 (expected mortality >99%). The patient survived without underperfusion-related damage. We conclude that norepinephrine dosages could potentially be greatly increased in late shock. We must resist giving up flow escalation based on its numerical value.

Pressor Response to Noradrenaline in the Setting of Septic Shock: Anything New under the Sun-Dexmedetomidine, Clonidine? A Minireview

Progress over the last 50 years has led to a decline in mortality from ≈70% to ≈20% in the best series of patients with septic shock. Nevertheless, refractory septic shock still carries a mortality close to 100%. In the best series, the mortality appears related to multiple organ failure linked to comorbidities and/or an intense inflammatory response: shortening the period that the subject is exposed to circulatory instability may further lower mortality. Treatment aims at reestablishing circulation within a "central" compartment (i.e., brain, heart, and lung) but fails to reestablish a disorganized microcirculation or an adequate response to noradrenaline, the most widely used vasopressor. Indeed, steroids, nitric oxide synthase inhibitors, or donors have not achieved overwhelming acceptance in the setting of septic shock. Counterintuitively, α 2-adrenoceptor agonists were shown to reduce noradrenaline requirements in two cases of human septic shock. This has been replicated in rat and sheep models of sepsis. In addition, some data show that α 2-adrenoceptor agonists lead to an improvement in the microcirculation. Evidence-based documentation of the effects of alpha-2 agonists is needed in the setting of human septic shock.

A rational approach to fluid therapy in sepsis

Aggressive fluid resuscitation to achieve a central venous pressure (CVP) greater than 8 mm Hg has been promoted as the standard of care, in the management of patients with severe sepsis and septic shock. However recent clinical trials have demonstrated that this approach does not improve the outcome of patients with severe sepsis and septic shock. Pathophysiologically, sepsis is characterized by vasoplegia with loss of arterial tone, venodilation with sequestration of blood in the unstressed blood compartment and changes in ventricular function with reduced compliance and reduced preload responsiveness. These data suggest that sepsis is primarily not a volume-depleted state and recent evidence demonstrates that most septic patients are poorly responsive to fluids. Furthermore, almost all of the administered fluid is sequestered in the tissues, resulting in severe oedema in vital organs and, thereby, increasing the risk of organ dysfunction. These data suggest that a physiologic, haemodynamically guided conservative approach to fluid therapy in patients with sepsis would be prudent and would likely reduce the morbidity and improve the outcome of this disease.

Centhaquin improves survival in a swine model of hemorrhagic shock

BACKGROUND

Hemorrhage is a frequent event in hospital and prehospital settings. The aim of the present study was to investigate whether centhaquin improves 24-h survival and reduces the total volume of required fluids in an established model of swine hemorrhagic shock.

MATERIAL AND METHODS

Twenty-five pigs were instrumented and subjected to hemorrhagic shock. The animals were randomly allocated in two experimental groups, the control (vehicle) (n = 10) and the centhaquin groups (0.015 mg/kg, n = 10); all animals received lactated Ringer solution in the resuscitation phase until their mean arterial pressure reached 90% of the baseline. A sham group (n = 5) was added a posteriori to mimic the hemodynamic profile of the centhaquin group.

RESULTS

A statistically significant difference was observed in the time required for the three groups to reach their target mean aortic pressure, 36.88 ± 3.26 min for the control group versus 9.40 ± 1.01 min for the sham group and 7.10 ± 0.97 min for the centhaquin group (P < 0.001). The total amount of fluids in the control and the sham groups was significantly higher when compared with that of the centhaquin-treated animals (P < 0.001). All 10 animals in the centhaquin group survived for 24 h, whereas only three animals survived in the control group and one animal in the sham group (P = 0.002).

CONCLUSIONS

Centhaquin 0.015 mg/kg administered in the fluid resuscitation phase resulted in lower volume of fluids and better survival compared with control and sham-operated animals.

Early management of severe sepsis: concepts and controversies

Sepsis is among the most common reasons for admission to ICUs throughout the world, and it is believed to be the third most common cause of death in the United States. The pathogenetic mechanism and physiologic changes associated with sepsis are exceedingly complex, but our understanding is evolving rapidly. The major pathophysiologic changes in patients with septic shock include vasoplegic shock (distributive shock), myocardial depression, altered microvascular flow, and a diffuse endothelial injury. These pathophysiologic changes play a central role in the management of sepsis. The early management of patients with severe sepsis and septic shock centers on the administration of antibiotics, IV fluids, and vasoactive agents, followed by source control. However, the specific approach to the resuscitation of patients with septic shock remains highly controversial. This review provides a practical and physiologic-based approach to the early management of sepsis and explores the controversies surrounding the management of this complex condition.

Re-thinking resuscitation: leaving blood pressure cosmetics behind and moving forward to permissive hypotension and a tissue perfusion-based approach

Definitions of shock and resuscitation endpoints traditionally focus on blood pressures and cardiac output. This carries a high risk of overemphasizing systemic hemodynamics at the cost of tissue perfusion. In line with novel shock definitions and evidence of the lack of a correlation between macro- and microcirculation in shock, we recommend that macrocirculatory resuscitation endpoints, particularly arterial and central venous pressure as well as cardiac output, be reconsidered. In this viewpoint article, we propose a three-step approach of resuscitation endpoints in shock of all origins. This approach targets only a minimum individual and context-sensitive mean arterial blood pressure (for example, 45 to 50 mm Hg) to preserve heart and brain perfusion. Further resuscitation is exclusively guided by endpoints of tissue perfusion irrespectively of the presence of arterial hypotension ('permissive hypotension'). Finally, optimization of individual tissue (for example, renal) perfusion is targeted. Prospective clinical studies are necessary to confirm the postulated benefits of targeting these resuscitation endpoints.

Therapeutic strategies for high-dose vasopressor-dependent shock

There is no consensual definition of refractory shock. The use of more than 0.5 mcg/kg/min of norepinephrine or epinephrine to maintain target blood pressure is often used in clinical trials as a threshold. Nearly 6% of critically ill patients will develop refractory shock, which accounts for 18% of deaths in intensive care unit. Mortality rates are usually greater than 50%. The assessment of fluid responsiveness and cardiac function can help to guide therapy, and inotropes may be used if hypoperfusion signs persist after initial resuscitation. Arginine vasopressin is frequently used in refractory shock, although definite evidence to support this practice is still missing. Its associations with corticosteroids improved outcome in observational studies and are therefore promising alternatives. Other rescue therapies such as terlipressin, methylene blue, and high-volume isovolemic hemofiltration await more evidence before use in routine practice.

Survival after shock requiring high-dose vasopressor therapy

BACKGROUND

Some patients with hypotensive shock do not respond to usual doses of vasopressor therapy. Very little is known about outcomes after high-dose vasopressor therapy (HDV). We sought to characterize survival among patients with shock requiring HDV. We also evaluated the possible utility of stress-dose corticosteroid therapy in these patients.

METHODS

We conducted a retrospective study of patients with shock requiring HDV in the ICUs of five hospitals from 2005 through 2010. We defined HDV as receipt at any point of ≥ 1 μg/kg/min of norepinephrine equivalent (calculated by summing norepinephrine-equivalent infusion rates of all vasopressors). We report survival 90 days after hospital admission. We evaluated receipt of stress-dose corticosteroids, cause of shock, receipt of CPR, and withdrawal or withholding of life support therapy.

RESULTS

We identified 443 patients meeting inclusion criteria. Seventy-six (17%) survived. Survival was similar (20%) among the 241 patients with septic shock. Among the 367 nonsurvivors, 254 (69%) experienced withholding/withdrawal of care, and 115 (31%) underwent CPR. Stress-dose corticosteroid therapy was associated with increased survival (P = .01).

CONCLUSIONS

One in six patients with shock survived to 90 days after HDV. The majority of nonsurvivors died after withdrawal or withholding of life support therapy. A minority of patients underwent CPR. Additionally, stress-dose corticosteroid therapy appears reasonable in patients with shock requiring HDV.

High-dose norepinephrine treatment: determinants of mortality and futility in critically ill patients

BACKGROUND

Critically ill patients with circulatory shock sometimes need rescue treatment with high doses of norepinephrine, a treatment that may be associated with a poor outcome because of excessive vasoconstriction.

OBJECTIVE

To evaluate the outcome of treatment and its determinants in patients with circulatory shock who received high doses of norepinephrine in the intensive care unit and to identify indicators of futility for the treatment.

METHODS

A retrospective study was done on 113 consecutive patients with circulatory shock who received 0.9 μg/kg per minute or greater of norepinephrine during at least 1 hour at any time in the intensive care unit. Data were extracted from the electronic patient data management system according to a predefined checklist.

RESULTS

A total of 39 patients survived for 28 days after admission to the intensive care unit. The variables independently associated with 28-day mortality in multivariable models included low urine flow, high lactate levels, high organ failure score, high prothrombin time, and need for epinephrine cotreatment. The reason, dose, and duration of norepinephrine administration did not have prognostic significance. Scores greater than 40 on the Acute Physiology and Chronic Health Evaluation II, bicarbonate levels less than 9.0 mEq/L, or receipt of an epinephrine dose of 0.25 μg/kg per minute or greater were associated with 100% mortality.

CONCLUSIONS

Although the cause of shock and treatment with norepinephrine were not predictive of death when high doses of the drug were deemed necessary, rescue treatment with high-dose norepinephrine is futile in patients with severe disease and metabolic acidemia.

Vascular hyporesponsiveness to vasopressors in septic shock: from bench to bedside

PURPOSE

To delineate some of the characteristics of septic vascular hypotension, to assess the most commonly cited and reported underlying mechanisms of vascular hyporesponsiveness to vasoconstrictors in sepsis, and to briefly outline current therapeutic strategies and possible future approaches.

METHODS

Source data were obtained from a PubMed search of the medical literature with the following MeSH terms: Muscle, smooth, vascular/physiopathology; hypotension/etiology; shock/physiopathology; vasodilation/physiology; shock/therapy; vasoconstrictor agents.

RESULTS

Nitric oxide (NO) and peroxynitrite are crucial components implicated in vasoplegia and vascular hyporeactivity. Vascular ATP-sensitive and calcium-activated potassium channels are activated during shock and participate in hypotension. In addition, shock state is characterized by inappropriately low plasma glucocorticoid and vasopressin concentrations, a dysfunction and desensitization of alpha-receptors, and an inactivation of catecholamines by oxidation. Numerous other mechanisms have been individualized in animal models, the great majority of which involve NO: MEK1/2-ERK1/2 pathway, H(2)S, hyperglycemia, and cytoskeleton dysregulation associated with decreased actin expression.

CONCLUSIONS

Many therapeutic approaches have proven their efficiency in animal models, especially therapies directed against one particular compound, but have otherwise failed when used in human shock. Nevertheless, high doses of catecholamines, vasopressin and terlipressin, hydrocortisone, activated protein C, and non-specific shock treatment have demonstrated a partial efficiency in reversing sepsis-induced hypotension.

Reversal of refractory septic shock with drotrecogin alpha (activated)

OBJECTIVE

We previously reported that early continuous veno-venous hemodiafiltration (CVVHDF) enables rapid identification of a subgroup of patients with "refractory" septic shock and a 100% risk of death. The objective of this study was to investigate whether early administration of drotrecogin alpha (activated) (DrotAA) to this selected subgroup of septic patients at extremely high risk of death would significantly improve prognosis.

METHOD

Prospective observational study in a medical intensive-care unit of a University Hospital. Twenty-three patients with refractory septic shock were included. "Refractory" shock was defined as persistent circulatory failure despite adequate circulatory support, associated with persisting lactic acidosis despite early CVVHDF. Response to CVVDHF was assessed after 6 h of this continuous procedure. Patients selected by this strategy received DrotAA infusion for four days.

RESULTS

The 28-day mortality rate of the 23 patients was 39%. No difference was observed at inclusion between survivors and nonsurvivors. In patients who finally survived, 12 h of DrotAA infusion was associated with a significant decrease in lactic acidosis and in norepinephrine dose.

CONCLUSION

DrotAA therapy was associated with unexpectedly high 28-day survival in patients with "refractory" septic shock.

Fluid therapy and the use of albumin in the treatment of severe traumatic brain injury

BACKGROUND

Evidence-based guidelines for severe traumatic brain injury (TBI) do not include strategies for fluid administration. The protocol used in this study includes albumin administration to maintain normal colloid osmotic pressure and advocates a neutral to slightly negative fluid balance. The aim of this study was to analyze the occurrence of organ failure and the mortality in patients with severe TBI treated by a protocol that includes defined strategies for fluid therapy.

METHODS

Ninety-three patients with severe TBI and Glasgow Coma Score <or=8 were included during 1998-2001. Medical records of the first 10 days were retrieved. Organ dysfunction was evaluated with the Sequential Organ Failure Assessment (SOFA) score. Mortality was assessed after 10 and 28 days, 6 and 18 months.

RESULTS

The total fluid balance was positive on days 1-3, and negative on days 4-10. The crystalloid balance was negative from day 2. The mean serum albumin was 38+/-6 g/l. Colloids constituted 40-60% of the total fluids given per day. Furosemide was administered to 94% of all patients. Severe organ failure defined as SOFA >or=3 was evident only for respiratory failure, which was observed in 29%. None developed renal failure. After 28 days, mortality was 11% and, after 18 months, it was 14%.

CONCLUSIONS

A protocol including albumin administration in combination with a neutral to a slightly negative fluid balance was associated with low mortality in patients with severe TBI in spite of a relatively high frequency (29%) of respiratory failure, assessed with the SOFA score.

Hemodynamic management of septic shock

Septic shock is characterized by profound cardiovascular alterations, including hypovolemia, severe alterations in vascular tone, and myocardial depression. These effects can lead to tissue hypoperfusion, the persistence of which could contribute to multiple organ failure. In addition, regional blood flow alterations and microvascular blood flow alterations may coexist and persist even after whole body hemodynamic alterations are corrected. Early aggressive interventions to improve oxygen delivery have been shown to improve outcome, but ongoing hemodynamic support is often required. This review will examine the hemodynamic management of patients with septic shock.

Cardiovascular response to dopamine and early prediction of outcome in septic shock: a prospective multiple-center study

OBJECTIVES

To compare mortality rates between dopamine-sensitive (Dopa-S) and dopamine-resistant (Dopa-R) septic shock patients, the latter group defined by a mean arterial pressure <70 mm Hg despite the use of 20 mug/kg/min dopamine.

DESIGN

A human, prospective observational, multiple-center, clinical trial.

SETTING

Ten intensive care units from ten hospitals.

PATIENTS

110 patients with septic shocks.

INTERVENTIONS

Following volume resuscitation, patients were treated by a rapid increase in dopamine infusion from 10 to 20 mug/kg/min. If mean arterial pressure remained <70 mm Hg, dopamine treatment was promptly switched to norepinephrine or epinephrine.

MEASUREMENTS AND MAIN RESULTS

Dopamine sensitivity, arterial gas, lactate, and organ system failure scores were measured at admission and after 6, 12, 24, 48, 72, 96, and 120 hrs. The overall 28-day mortality rate was 54% for the entire population under study. In multivariate analysis, independent predictors of death were dopamine resistance (odds ratio, 9.5; 95% confidence interval, 3-25), arterial lactate >3.5 mmol/L (odds ratio, 1.75; 95% confidence interval, 1.06-2.55), and Sepsis-related Organ Failure Assessment score >10 (odds ratio, 1.40; 95% confidence interval, 1.07-2.12). Of the 110 patients studied, 66 were observed to be resistant to dopamine (60%). In the Dopa-S group, the 28-day mortality rate was 16% (seven of 44 patients) compared with 78% (52 of 66 patients) in the Dopa-R group (p = .0006). The capacity of dopamine resistance to predict death was associated with a sensitivity of 84% and a specificity of 74%. At 24 hrs, the association of dopamine resistance to a lactate level >3.5 mmol/L improved the prognostic value (sensitivity, 90%, specificity, 92%).

CONCLUSIONS

Dopamine sensitivity is associated with decreased mortality rate. Early recognition of dopamine resistant septic shock could allow for better screening of patients with an ominous prognosis.

Meta-analysis of hemodynamic optimization: relationship to methodological quality

Introduction

To review systematically the effect of interventions aimed at hemodynamic optimization and to relate this to the quality of individual published trials.

Methods

A systematic, computerized bibliographic search of published studies and citation reviews of relevant studies was performed. All randomized clinical trials in which adult patients were included in a trial deliberately aiming at an optimized or maximized hemodynamic condition of the patients (with oxygen delivery, cardiac index, oxygen consumption, mixed venous oxygen saturation and/or stroke volume as end-points) were selected. A total of 30 studies were selected for independent review. Two reviewers extracted data on population, intervention, outcome and methodological quality. Agreement between reviewers was high: differences were eventually resolved by third-party decision. The methodological quality of the studies was moderate (mean 9.0, SD 1.7), and the outcomes of the randomized clinical trials were not related to their quality.

Results

Efforts to achieve an optimized hemodynamic condition resulted in a decreased mortality rate (relative risk ratio (RR) 0.75 (95% confidence interval (CI) 0.62 to 0.90) in all studies combined. This was due to a significantly decreased mortality in peri-operative intervention studies (RR 0.66 (95% CI 0.54 to 0.81). Overall, patients with sepsis and overt organ failure do not benefit from this method (RR 0.92 (95% CI 0.75 to 1.11)).

Conclusion

This systematic review showed that interventions aimed at hemodynamic optimization reduced mortality. In particular, trials including peri-operative interventions aimed at the hemodynamic optimization of high-risk surgical patients reduce mortality. Overall, this effect was not related to the trial quality.

Early veno-venous haemodiafiltration for sepsis-related multiple organ failure

Introduction

We conducted a prospective observational study from January 1995 to December 2004 to evaluate the impact on recovery of a major advance in renal replacement therapy, namely continuous veno-venous haemodiafiltration (CVVHDF), in patients with refractory septic shock.

Method

CVVHDF was implemented after 6–12 hours of maximal haemodynamic support, and base excess monitoring was used to evaluate the improvement achieved. Of the 60 patients studied, 40 had improved metabolic acidosis after 12 hours of CVVHDF, with a progressive improvement in all failing organs; the final mortality rate in this subgroup was 30%. In contrast, metabolic acidosis did not improve in the remaining 20 patients after 12 hours of CVVHDF, and the mortality rate in this subgroup was 100%. The crude mortality rate for the whole group was 53%, which is significantly lower than the predicted mortality using Simplified Acute Physiology Score II (79%).

Conclusion

Early CVVHDF may improve the prognosis of sepsis-related multiple organ failure. Failure to correct metabolic acidosis rapidly during the procedure was a strong predictor of mortality.

Impact of high volume hemofiltration on hemodynamic disturbance and outcome during septic shock

The purpose of this study was to evaluate the effect of high volume continuous venovenous hemofiltration (HVCVVH) on hemodynamic and outcome in patients with septic shock. The primary end point was mortality at 28 days. Study design was a prospective case series, and study setting was a 12 bed intensive care unit at a university hospital. A total of 24 consecutive patients with septic shock were included, with dysfunction of more than two organs. All patients were treated by HVCVVH with ultrafiltration rate between 40 ml x kg(-1) x hr(-1) and 60 ml x kg(-1) x hr(-1) for 96 hours. In all patients, the increase in hemodynamic parameters was statistically significant (p < 0.05), with a significant linear decrease in norepinephrine doses (p < 0.05). The predicted 28 day mortality by three different severity scores was more than 70%, and the mortality in the hemofiltration group was 46% (p < 0.075). In the present study of septic shock patients with organ dysfunction, the hemodynamic parameters increased regularly during treatment by HVCVVH. This study suggests a beneficial effect of HVCVVH on 28 day mortality (46% vs. 70%), and further studies with larger cohorts are required.

Early and exclusive use of norepinephrine in septic shock

BACKGROUND

The timing and use of norepinephrine (noradrenaline) (NE) in septic shock remain a matter of controversy.

AIM

To study the outcome of septic patients treated with early and exclusive NE.

SETTING

Tertiary Intensive Care Unit.

PATIENTS

142 patients with septic shock.

INTERVENTION

Exclusive NE infusion within 24 hours of admission to ICU.

METHODS AND MAIN RESULTS

Retrospective analysis of data from a unit database identified 142 patients. Their median admission simplified acute physiology score (SAPS II) score was 46 [38, 56] with 98 (69%) receiving mechanical ventilation. Mean arterial pressure (MAP) at the start of NE infusion was 60 [58, 68]mmHg. NE infusion was started at a median of 1.3 [0.3, 5.0]h after ICU admission. Restoration and maintenance of target MAP was achieved initially in all patients and, in 61.3%, within 30 min. The median peak dose of NE was 0.28 [0.14, 0.61]microg/(kg min) and the duration of infusion was 88 [42, 175]h. SAPS II predicted mortality was 40.8%, however, only 34.5% (P = 0.27) died. Among the most severely ill patients (SAPS II score >56) actual mortality was 50.0% versus 74.7% predicted (P = 0.07).

CONCLUSIONS

Early and exclusive use of NE in hyperdynamic septic shock achieved a stable MAP >75 mmHg in all patients. Survival compared favorably with that predicted by illness severity scores.

Septic Shock of Early or Late Onset

STUDY OBJECTIVES

To determine possible differences in morbidity and mortality between early and late onset of septic shock in ICU patients.

DESIGN

Systematic data collection.

SETTING

Thirty-one-bed, mixed, medicosurgical ICU in a university hospital.

PATIENTS

All 65 patients who acquired septic shock after admission to the ICU between February 1999 and April 2000.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Forty-one of the 65 patients presented with septic shock within 24 h of admission to the ICU (early septic shock [ESS]); the other 21 patients acquired septic shock > 24 h after ICU admission (late septic shock [LSS]). Eleven patients had a second episode (7 patients in the ESS group, and 4 patients in the LSS group), and 1 patient in the LSS group had a third episode of septic shock. Patients with ESS had higher APACHE (acute physiology and chronic health evaluation) II (mean +/- SD, 26 +/- 6 vs 20 +/- 6; p = 0.002) and sequential organ failure assessment (SOFA) scores (11 +/- 3 vs 7 +/- 3, p < 0.001) on ICU admission, and a higher blood lactate concentration at the onset of shock (median 3.70 mEq/L; interquartile range, 2.6 to 6.6 mEq/L; vs median, 2.50 mEq/L [interquartile range, 1.8 to 4.0 mEq/L], p = 0.03) than patients with LSS. However, the duration of septic shock (median, 42 h [interquartile range, 21 to 97 h] vs median, 93 h [interquartile range, 32 to 241 h], p = 0.058) and the length of ICU stay after the onset of septic shock (median, 75 h; [interquartile range, 38 to 203 h] vs median, 321 h [interquartile range, 96 to 438 h], p = 0.018), was shorter in patients with ESS than patients with LSS. The ICU mortality rate was 63% (26 patients) in the ESS group, and 88% (21 patients) in the LSS group (p = 0.071). At the onset of the first episode of shock, patients with ESS had higher SOFA scores (11 +/- 3 vs 9 +/- 3, p = 0.045), lower pH (7.24 +/- 0.15 vs 7.33 +/- 0.12, p = 0.01), and were treated with higher doses of dopamine (median, 20 microg/kg/min [interquartile range, 14 to 20 microg/kg/min] vs median, 12 microg/kg/min [interquartile range, 8 to 20 microg/kg/min], p = 0.028) than patients with LSS.

CONCLUSIONS

Septic shock is more severe when of early onset, as reflected by more severe organ dysfunction, greater lactic acidosis, and higher vasopressor requirements, yet the outcome is better, as reflected by a shorter duration of the shock episode, shorter ICU stay, and slightly lower mortality rates. These differences may influence clinical trials of therapeutic agents for sepsis, and should be taken into account when analyzing the results.

Norepinephrine and vital organ blood flow during experimental hyperdynamic sepsis

OBJECTIVE

To study the effect of norepinephrine (NE) infusion on cerebral, coronary, renal and mesenteric blood flow during sepsis.

DESIGN AND SETTING

Randomised placebo-controlled animal trial in the animal laboratory of university physiology institute.

ANIMALS

Seven merino cross-ewes.

INTERVENTIONS

Chronic implantation of flow probes (aorta, renal, mesenteric and coronary artery and sagittal sinus). Induction of sepsis by intravenous bolus of E. coli (3 x 10(9)). After the onset of hyperdynamic sepsis sheep were randomly allocated to either NE (0.4 microg kg(-1) min(-1)) or placebo for 6 h.

MEASUREMENTS AND RESULTS

E. coli induced hypotension, fever, oliguria, tachycardia and tachypnoea. It increased cardiac output and renal, mesenteric and coronary blood flows. Sagittal flow remained unchanged. Compared to placebo NE infusion restored mean arterial blood pressure and further increased cardiac output. The increases in renal, mesenteric and coronary blood flow were unaffected. Sagittal flow was also unaltered. Compared to placebo NE increased myocardial performance, mean urine output and creatinine clearance at 2 h.

CONCLUSIONS

We conclude that hyperdynamic sepsis increases blood flow to heart, gut and kidney and that NE further increases cardiac output, blood pressure, myocardial performance, and urine output and creatinine clearance while maintaining regional blood flow.

Low stretch ventilation strategy in acute respiratory distress syndrome: eight years of clinical experience in a single center

CONTEXT

In recent years, protective ventilation with airway pressure limitation has constituted a major advance in acute respiratory distress syndrome treatment and has led to a substantial improvement in prognosis. With this therapeutic rationale, one may even question nowadays whether the severity of respiratory failure still influences mortality.

OBJECTIVE

To determine whether the severity of respiratory failure, scored according to the usual criteria, still influences mortality in acute respiratory distress syndrome patients when a low stretch ventilation was used and to assess the impact on mortality of other nonpulmonary organ dysfunction, particularly circulatory failure.

DESIGN AND SETTING

A retrospective study conducted in the medical intensive care unit of a French university hospital from October 1993 to December 2001. PATIENTS A total of 150 acute respiratory distress syndrome patients who were administered uniform protective ventilation with a limited plateau pressure (<30 cm H2O), a low positive end-expiratory pressure (<10 cm H2O), and the same strategy concerning hemodynamic support and dialysis when required.

MAIN OUTCOME AND MEASURES

Mean age, general severity index (Simplified Acute Physiologic Score II), number of associated organ failures (Logistic Organ Dysfunction Score), respiratory severity indices (Pao2/Fio2, Lung Injury Severity Score), and severity of initial circulatory failure (circulatory failure present at admission or that developed during the first 48 hrs) were compared, according to recovery or death, and evaluated by a logistic regression model, which allows simultaneous control of multiple factors.

RESULTS

The average mortality rate for the whole group was 38%, with 93 patients recovering after an average duration of mechanical ventilation of 18 +/- 13 days. The major factor significantly and independently associated with probability of dying was the severity of circulatory failure (p =.0001, odds ratio = 10.17). Patients free from initial circulatory failure (39 patients) had a 95% recovery rate.

CONCLUSION

With our low stretch strategy, the severity of circulatory failure was the main determinant of acute respiratory distress syndrome prognosis. Patients with isolated respiratory failure during the first 48 hrs of respiratory support have an excellent chance of recovery when treated with protective ventilation associated with a low positive end-expiratory pressure.

Hemodynamic and metabolic effects of low-dose vasopressin infusions in vasodilatory septic shock

OBJECTIVE

To investigate the physiologic effects of exogenous vasopressin as a potential alternative to traditional high-dose catecholamine therapy for septic patients with vascular hyporeactivity to catecholamines.

DESIGN

Prospective, case-controlled study.

SETTING

Intensive care unit of a university hospital.

PATIENTS

Vasopressin was infused in 16 critically ill septic patients who remained persistently hypotensive despite infusions of pharmacologic doses of catecholamines.

INTERVENTION

Continuous intravenous infusion of vasopressin at 0.04 units/min for 16 hrs, in place of escalating the amount of catecholamines being infused.

MEASUREMENTS AND MAIN RESULTS

After administration of vasopressin, systemic vascular resistance and mean arterial pressure were immediately and significantly increased in comparison with the values obtained just before vasopressin. When the vasopressin infusions were discontinued, mean arterial pressure decreased immediately and dramatically. We did not detect any obvious adverse cardiac effects during the vasopressin infusions. Vasopressin had no effect on other hemodynamic parameters or any of the metabolic parameters studied, including measures of oxygenation, plasma glucose, or electrolytes. Urine output increased significantly during the administration of vasopressin, although this effect may be nonspecific. Lactate concentrations decreased, particularly in the survival group, but the decreases were not significant. Overall survival was 56%.

CONCLUSIONS

Low-dose vasopressin infusions increased mean arterial pressure, systemic vascular resistance, and urine output in patients with vasodilatory septic shock and hyporesponsiveness to catecholamines. The data indicate that low-dose vasopressin infusions may be useful in treating hypotension in these patients.

The Year in Review: Critical Care Medicine

Background: There have been significant recent advances in the pharmacotherapeutic management of critically ill patients. The purpose of this article is to review and discuss the most pertinent published literature in the areas of neurology, cardiovascular diseases, infectious diseases, nephrology, hematology, and gastroenterology as it pertains to critical care in order to provide an update for the critical care practitioner.

Methods: We performed a Medline search from July 1999 to December 2000 utilizing terms relating to the pharmacotherapy of the specific aforementioned topics in critical care medicine. We focused on English-language clinical studies performed in adult intensive care unit (ICU) patients. From these articles we selected those that would have a practical impact on drug therapy in the ICU or the development of drug usage guidelines for critically ill patients. Review articles were generally not included.

Results: The following topics were found to be either new developments or of potentially significant impact in the management of adult critically ill patients. In the area of neurology, advances were found with respect to optimization of regimens for sedative and neuromuscular blocking agents, validation of sedation scales and tools, and in the treatment of head injury patients. In the cardiovascular diseases, most studies related to the hemodynamic support of septic shock. We focus on developments in fluid resuscitation, optimization of global and regional oxygen transport variables, the repositioning of vasopressor agents, and a return to the use of steroids. Given the high mortality rate associated with the development of acute renal failure in the ICU, there has been a consistent attempt to develop preventative and treatment strategies for these patients, including optimization of antimicrobial dosing methods. Several epidemiological and longitudinal studies document changes in multi-drug antimicrobial resistance patterns. The use of treatment guidelines for antimicrobials in the critically ill improves outcomes in most patients. Significant attention has focused on the characterization of anemia in the ICU and the development of alternative pharmacological strategies in its treatment. Finally, in gastroenterology, the main focus has been the investigation of methods to optimize the delivery of enteral nutrition given its proven benefits in critically ill patients.

Conclusions: Significant advances in the areas of neurological, cardiovascular, infectious diseases, renal, hematological, and gastrointestinal issues in the pharmacotherapy of critically ill patients have been published over the course of the past year. Many of these studies have yielded data that may be incorporated into the pharmacotherapeutic management of ICU patients, hence maximizing outcomes.