Vasopressin in the ICU

An Uncommon Presentation of Vasopressin-Induced Purpura Fulminans

Purpura fulminans (PF) is a rarely encountered rapidly evolving dermatological manifestation of ischemia, particularly in critically ill patients. Considered one of the very few dermatological emergencies, it has high mortality rate where patients often succumb to the illness. It can manifest in three forms: neonatal, idiopathic, and the more commonly infectious variety, which can be secondary to mostly bacterial and rarely viral etiology. It is also reported to be highly associated with disseminated intravascular coagulation (DIC), heparin-induced thrombocytopenia (HIT), and acute hepatic failure (AHF). Hereditary or acquired deficiency of protein C and dysregulation of the coagulation cascade, mainly protein C-thrombomodulin, has been implicated in the pathogenesis. We present a 55-year-old male admitted to the intensive care unit for diabetic ketoacidosis (DKA) and septic shock. Along with initiating management protocol for DKA and broad-spectrum antibiotics, he was initially started on norepinephrine for septic shock. Because of persistent refractory septic shock, he was subsequently initiated on phenylephrine and vasopressin to maintain adequate perfusion. The following day, he was found to have sharply demarcated blackish non-blanching discoloration on bilateral knees, lower limbs, and scrotum, sparing the acral regions. This cutaneous manifestation persisted throughout his hospital course, although it improved after discontinuation of vasopressin while continuing with other pressors. Vasopressin has been implicated in a few instances of skin necrosis; however, PF has rarely been documented and never within 1 day like ours. This case demonstrates a unique development of PF likely from vasopressin after ruling out the diagnoses of DIC, HIT, thrombotic thrombocytopenic purpura, and AHF.

Comparison of gastric reactance with commonly used perfusion markers in a swine hypovolemic shock model

Background

The gut has been hypothesized to be a protagonist tissue in multiple organ dysfunction syndrome (MODS) for the past three decades. Gastric reactance (XL) is a potential perfusion marker derived from gastric impedance spectroscopy (GIS), which is an emerging tool through which living tissue can be continuously measured to determine its pathophysiological evolution. This study aimed to compare the performance of XL [positive predictive values (PPV), negative predictive values (NPV), and area under the curve (AUC)] against commonly used perfusion markers before and during hypovolemic shock in swine subjects.

Methods

Prospective, controlled animal trial with two groups, control group (CG) N = 5 and shock (MAP ≤ 48 mmHg) group (SG) N = 16. Comparison time points were defined as T-2 (2 h before shock), T-1 (1 h before shock), T0 (shock), T1 (1 h after shock), and T2 (2 h after shock). Shock severity was assessed through blood gases, systemic and hemodynamic variables, and via histological examination for assessing inflammation-edema and detachment in the gastric mucosa. Macroscopic assessment of the gastric mucosa was defined in five levels (0—normal mucosa, 1—stippling or epithelial hemorrhage, 2—pale mucosa, 3—violet mucosa, and 4—marmoreal mucosa). Receiver Operating Characteristic (ROC) curves of perfusion markers and XL were calculated to identify optimal cutoff values and their individual ability to predict hypovolemic shock.

Results

Comparison among the CG and the SG showed statistically significant differences in XL measurements at T-1, T0, T1, and T2, while lactate showed statistically significant differences until T1 and T2. Statistically significant differences were detected in mucosa class (p < 0.001) and in inflammation-edema in the gastric body and the fundus (p = 0.021 and p = 0.043). The performance of the minimum XL value per subject  per event (XL_Min) was better (0.81 ≤ AUC ≤ 0.96, 0.93 ≤ PPV ≤ 1.00, 0.45 ≤ NPV ≤ 0.83) than maximum lactate value (Lac_Max) per subject per event (0.29 ≤ AUC ≤ 0.82, 0.82 ≤ PPV ≤ 0.91, 0.24 ≤ NPV ≤ 0.82). Cutoff values for XL_Min show progressive increases at each time point, while cutoff values for Lac_Max increase only at T2.

Conclusions

XL proved to be an indirect and consistent marker of inadequate gastric mucosal perfusion, which shows significant and detectable changes before commonly used markers of global perfusion under the hypovolemic shock conditions outlined in this work.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40635-022-00476-1.

Clinical Efficiency of Vasopressin or Its Analogs in Comparison With Catecholamines Alone on Patients With Septic Shock: A Systematic Review and Meta-Analysis

BACKGROUND

Vasopressin is an efficient remedy for septic shock patients as its great capacity in promoting hemodynamic stabilization. The aim of current systematic review and meta-analysis is to compare the clinical efficiency of vasopressin or its analogs with sole catecholamines on patients with septic shock.

METHODS

A systematic search of Cochrane Library, EMBASE, and PubMed online databases was performed up to 30 Oct 2019 to identify randomized controlled trials comparing use of vasopressin or its analogs (e.g., terlipressin, selepressin) with administration of catecholamines alone.

RESULTS

We included 23 RCTs with 4,225 patients in the current study. Compared with solely use of catecholamines, administration of vasopressin or its analogs was not associated with reduced 28-day or 30-day mortality among patients with septic shock [RR=0.94 (95% CI, 0.87-1.01), P=0.08, I2 = 0%]. The result of primary endpoint remained unchanged after conducting sensitivity analysis. Despite a significantly higher risk of digital ischemia in patients receiving vasopressin or its analogs [RR=2.65 (95% CI, 1.26-5.56), P < 0.01, I2 = 48%], there was no statistical significance in the pooled estimate for other secondary outcomes, including total adverse events, arrhythmia, acute myocardial infarction (AMI) and cardiac arrest, acute mesenteric ischemia, ICU/hospital length of stay, and mechanical ventilation (MV) duration.

CONCLUSIONS

The administration of vasopressin or its analogs was not associated with reduced 28-day or 30-day mortality among patients with septic shock, while an increased incidence of digital ischemia should be noted in patients receiving agonists for vasopressin receptors.

The effects and safety of vasopressin receptor agonists in patients with septic shock: a meta-analysis and trial sequential analysis

BACKGROUND

The aim of this study was to evaluate the effects and safety of vasopressin receptor agonists in patients with septic shock.

METHODS

PubMed, EMBASE, and Cochrane library were searched for randomized controlled trials evaluating the effects of vasopressin receptor agonists in septic shock patients. Two reviewers performed literature selection, data extraction, and quality evaluation independently. The primary outcome was mortality. And secondary outcomes included intensive care unit (ICU) length of stay, duration of mechanical ventilation, and incidence of adverse events. In addition, a trial sequential analysis (TSA) was performed.

RESULTS

Twenty studies were eligible for meta-analysis. The results showed vasopressin receptor agonists use was associated with reduced mortality (relative risk (RR) 0.92; 95% confidence interval (CI) 0.84 to 0.99; I2 = 0%). Nevertheless, they had no significant effects on ICU length of stay (mean deviation (MD) - 0.08, 95% CI, - 0.68 to 0.52, I2 = 0%) and duration of mechanical ventilation (MD - 0.58, 95% CI - 1.47 to 0.31, I2 = 57%). Additionally, there was no significant difference in total adverse events between two groups (RR 1.28, 95% CI 0.87 to 1.90, I2 = 57%), but vasopressin receptor agonists administration could significantly increase the risk of digital ischemia (RR 4.85, 95% CI 2.81 to 8.39, I2 = 26%). Finally, there was no statistical difference of cardiovascular events (RR 0.91, 95% CI 0.53 to 1.57, I2 = 1%), arrhythmia (0.77, 95% CI 0.48 to 1.23, I2 = 23%), mesenteric ischemia (0.83, 95% CI 0.44 to 1.55, I2 = 0%), diarrhea (2.47, 95% CI 0.77 to 7.96, I2 = 49%), cerebrovascular events (1.36, 95% CI 0.18 to 10.54, I2 = 0%), and hyponatremia (1.47, 95% CI 0.84 to 2.55, I2 = 0%) between two groups. Egger's test showed there was no significant publication bias among studies (P = 0.36).

CONCLUSIONS

The use of vasopressin might result in reduced mortality in patients with septic shock. An increased risk of digital ischemia must be taken into account.

Does Vasopressin Exacerbate Cerebral Edema in Patients with Severe Traumatic Brain Injury?

Arginine vasopressin (AVP) is often used as an alternative pressor to catecholamines (CATs). However, unlike CATs, AVP is a powerful antidiuretic that could promote edema. We tested the hypothesis that AVP promoted cerebral edema and/or increased requirements for osmotherapy, relative to those who received CATs, for cerebral perfusion pressure (CPP) management after traumatic brain injury (TBI). This is a retrospective review of 286 consecutive TBI patients with intracranial pressure monitoring at a single institution from September 2008 to January 2015. Cerebral edema was quantitated using CT attenuation in prespecified areas of gray and white matter. Results: To maintain CPP >60 mm Hg, 205 patients required no vasopressors, 41 received a single CAT, 12 received AVP, and 28 required both. Those who required no pressors were generally less injured; required less hyperosmolar therapy and less total fluid; and had lower plasma Na, lower intracranial pressure, less edema, and lower mortality (all P < 0.05). Edema; daily mean, minimum, and maximum Na levels; and mortality were similar with AVP versus CATs, but the daily requirement of mannitol and 3 per cent NaCl were reduced by 45 and 35 per cent (both P < 0.05). In patients with TBI who required CPP therapy, AVP reduced the requirements for hyperosmolar therapy and did not delay resolution or increase cerebral edema compared with CATs.

Temporal trends in the utilization of vasopressors in intensive care units: an epidemiologic study

Background

The choice of vasopressor use in the intensive care unit (ICU) depends primarily on provider preference. This study aims to describe the rate of vasopressor utilization and the trends of each vasoactive agent usage in the ICU over the span of 7 years in a tertiary referral center.

Methods

All adult ICU admissions, including medical, cardiac, and surgical ICUs from January 1st, 2007 through December 31st, 2013 were included in this study. Vasopressor use was defined as the continuous intravenous administration of epinephrine, norepinephrine, phenylephrine, dopamine, or vasopressin within a given ICU day. The vasopressor utilization index (VUI) was defined as the proportion of ICU days on each vasoactive agent divided by the total ICU days with vasopressor usage.

Results

During the study period, 72,005 ICU admissions and 272,271 ICU days were screened. Vasopressors were used in 19,575 ICU admissions (27 %) and 59,811 ICU days (22 %). Vasopressin was used in 24,496 (41 %), epinephrine in 23,229 (39 %), norepinephrine in 20,648 (34 %), dopamine in 9449 (16 %), and phenylephrine in 7508 (13 %) ICU days. The VUI_{norepinephrine} increased from 0.24 in 2007 to 0.46 in 2013 and VUI_{phenylephrine} decreased from 0.20 in 2007 to 0.08 in 2013 (p < 0.001 both). For epinephrine, dopamine, and vasopressin VUI did not change over the course of study.

Conclusion

Vasopressors were used in about one fourth of ICU admissions and about one-fifth of ICU days. Although vasopressin is the most commonly used vasopressor, the use of norepinephrine found to have an increasing trajectory.

Electronic supplementary material

The online version of this article (doi:10.1186/s40360-016-0063-z) contains supplementary material, which is available to authorized users.

Vasopressin and terlipressin in adult vasodilatory shock: a systematic review and meta-analysis of nine randomized controlled trials

Introduction

Catecholamines are the most used vasopressors in vasodilatory shock. However, the development of adrenergic hyposensitivity and the subsequent loss of catecholamine pressor activity necessitate the search for other options. Our aim was to evaluate the effects of vasopressin and its analog terlipressin compared with catecholamine infusion alone in vasodilatory shock.

Methods

A systematic review and meta-analysis of publications between 1966 and 2011 was performed. The Medline and CENTRAL databases were searched for studies on vasopressin and terlipressin in critically ill patients. The meta-analysis was limited to randomized controlled trials evaluating the use of vasopressin and/or terlipressin compared with catecholamine in adult patients with vasodilatory shock. The assessed outcomes were: overall survival, changes in the hemodynamic and biochemical variables, a decrease of catecholamine requirements, and adverse events.

Results

Nine trials covering 998 participants were included. A meta-analysis using a fixed-effect model showed a reduction in norepinephrine requirement among patients receiving terlipressin or vasopressin infusion compared with control (standardized mean difference, -1.58 (95% confidence interval, -1.73 to -1.44); P < 0.0001). Overall, vasopressin and terlipressin, as compared with norepinephrine, reduced mortality (relative risk (RR), 0.87 (0.77 to 0.99); P = 0.04). Vasopressin compared with norepinephrine decreased mortality in adult patients (RR, 0.87 (0.76 to 1.00); P = 0.05) and in patients with septic shock (42.5% vs. 49.2%, respectively; RR, 0.87 (0.75 to 1.00); P = 0.05; number needed to treat, 1 to 15). There was no difference in adverse events between the vasopressin and control groups (RR, 0.98 (0.65 to 1.47); P = 0.92).

Conclusions

Vasopressin use in vasodilatory shock is safe, associated with reduced mortality, and facilitates weaning of catecholamines. In patients with septic shock, use of vasopressin compared with norepinephrine may also decrease mortality.

Ileus development in the trauma/surgical intensive care unit: a process improvement evaluation

Ileus development has been associated with a wide range of complications among hospitalized patients, ranging from increased patient pain and discomfort to malnutrition, aspiration, delayed rehabilitation, and sepsis. This article examines factors that appeared to correlate with an increase in ileus development among patients in a trauma/surgical intensive care unit, with the goal of preventing the condition through nursing practice changes.

Postoperative Care of the Cardiac Surgical Patient

The subspecialty of interventional cardiology began in 1977. Since then, the discipline of interventional cardiology has matured rapidly, particularly with regards to ischemic heart disease. As a result, more patients are undergoing percutaneous catheter interventional therapy for ischemic heart disease and fewer patients are undergoing surgical myocardial revascularization. Those patients referred for surgical revascularization are generally older and have more complex problems. Furthermore, as the population ages more patients are referred to surgery for valvular heart disease. The result of these changes is a population of surgical patients older and sicker than previously treated.

Vasopressin attenuates TNF-mediated inflammation in the rat cremaster microcirculation

BACKGROUND

Our previous study in a swine polytrauma model suggested that equieffective systemic pressor doses of arginine vasopressin (AVP) versus phenylephrine (PE) have differential effects on the systemic and cerebral microcirculation. The purpose of this study was to directly observe the effects of AVP versus PE on inflammatory changes evoked by tumor necrosis factor alpha (TNF) in the skeletal muscle microcirculation.

METHODS

Seventy-five male rats (180-250 g) were anesthetized with isoforane, intubated and mechanically ventilated with 100% oxygen. The cremaster muscle microcirculation was prepared for intravital video microscopy while being suffused with a heated hetastarch-electrolyte solution. Fluorescein isothiocyanate-labeled albumin (100 mg/kg) was administered intravenously (i.v.) before one of five protocols. In series 1 (n = 20), either AVP (0.2 U/mL) or its vehicle was added to the suffusate for 10 minutes, washed out for 30 minutes, then TNF was suffused (5 ng/mL) for 30 minutes. In series 2 (n = 16), the protocol was similar, except AVP (0.2 U/mL) or an equieffective dose of PE (0.04 mg/mL) was administered i.v. (4.5 mL/h) for 15 minutes before, during, and 45 minutes after TNF suffusion. In series 3 (n = 12), the protocol was similar to series 2, except venous hemorrhage preceded i.v. AVP or PE. In series 4 (n = 15), the protocol was similar to series 3, except an AVP antagonist (vaprisol, 1 mg/kg i.v.) or its vehicle was administered after hemorrhage. In the control series (n = 13), inflammation was evaluated either with a different suffusate (lactated Ringers instead of hetastarch solution), different antigen (histamine instead of TNF), or hemorrhage with no antigen.

RESULTS

In series 1, the TNF-evoked increase in leukocyte infiltration (i.e., rolling), leukocyte activation (i.e., sticking), and macromolecular permeability (i.e., albumin extravasation) were attenuated with topical AVP versus vehicle (both p < 0.05), with no effect on venular blood flow (which determines sheer stress). In series 2, the TNF-evoked increase in infiltration, activation, and permeability were all attenuated, and arteriolar blood flow (which determines perfused capillary surface area and hydrostatic pressure) was reduced with i.v. AVP versus i.v. PE (all p < 0.05). In series 3, after hemorrhage to mean arterial pressure <50 mm Hg for 30 minutes, the TNF-evoked increase in infiltration and activation was attenuated, and arteriolar and venular blood flow were both reduced with i.v. AVP versus PE (all p < 0.05). In series 4, after hemorrhage, the TNF-evoked increase in leukocyte activation was potentiated with the vaprisol versus vehicle (p < 0.05) with no effect on arteriolar or venular blood flow. In series 5 (controls), suffusion with lactated Ringers' versus hetastarch solution more than doubled the TNF-evoked increase in activation (p < 0.05).

CONCLUSION

(1) AVP can attenuate TNF-evoked leukocyte infiltration, activation or permeability changes in the skeletal muscle microcirculation. (2) The mechanism is probably receptor mediated and does not entirely depend on sheer stress in venules or Starling forces in capillaries. (3) The magnitude of this anti-inflammatory effect is influenced by several conditions, including volume status, the colloid or crystalloid suffusion fluid, and is possibly specific to the antigenic stimulus (TNF vs. histamine).

Vasopressin as adjunct vasopressor for vasodilatory shock due to non-occlusive mesenteric ischemia

We present the case of an 83-year-old patient who underwent cardiac surgery and developed postoperative non-occlusive mesenteric ischemia (NOMI), which was treated with a local intra-arterial papaverine and prostaglandin E1 infusion. After successful mesenteric reperfusion, a multiple organ dysfunction syndrome with severe cardiovascular failure developed. High norepinephrine dosages (1.09 microg/kg body weight/min) and catecholamine-related complications (tachycardiac atrial fibrillation) required initiation of supplementary argininevasopressin (AVP) infusion (4 U/h). AVP stabilized vasodilatory shock, ensured adequate gut perfusion pressure and had no adverse clinical or angiographic effects on restitution of gut integrity. In conclusion, after reperfusion of NOMI in this patient, adjunct AVP therapy combined with local vasodilator infusion was beneficial as a potentially life-saving vasopressor.

Modulation of aquaporin-2/vasopressin2 receptor kidney expression and tubular injury after endotoxin (lipopolysaccharide) challenge

OBJECTIVE

Sepsis-induced organ dysfunctions remain prevalent and account for >50% of intensive care unit admissions for acute renal failure with a mortality rate nearing 75%. In addition to the fact that the mechanisms underlying the pathophysiology of sepsis-related acute renal failure are unclear, the impact on septic-induced acute renal failure of either norepinephrine, a gold-standard vasopressor, and arginine vasopressin, a candidate alternative, are not well understood.

DESIGN

Randomized and controlled in vivo study.

SETTING

Research laboratory and animal facilities.

SUBJECTS

Adult rats treated with endotoxin (lipopolysaccharide) and/or vasopressors.

INTERVENTIONS

Rats were intraperitoneally injected with lipopolysaccharide (12 mg/kg) or saline and then infused with either saline, 0.375 microg/microL arginine vasopressin, or 32.5 microg/microL norepinephrine for 18 hrs. These vasopressor rates yielded respective targeted blood levels observed in human septic shock.

MEASUREMENTS AND MAIN RESULTS

Renal function, including glomerular filtration rate and fraction, renal blood flow, aquaporin-2, and arginine vasopressin-2 (V2 receptor) networking, water and salt handling, and urinary protein excretion, were evaluated. After lipopolysaccharide challenge arginine vasopressin infusion: 1) impaired creatinine clearance without affecting renal blood flow, glomerular filtration rate, and fraction but reduced free-water clearance, both of which being partially restored by the V2 receptor antagonist SR-121463B; 2) decreased the recognized ability of arginine vasopressin alone to recruit aquaporin-2 to the apical membrane increase its mRNA expression and urinary release; 3) increased urinary protein content but decreased specific kidney injury molecule-1, and Clara cell protein-16 release (p < 0.05 vs. lipopolysaccharide alone). Conversely, norepinephrine infusion did not add to lipopolysaccharide-induced alteration of urine biochemistry, except for improved creatinine clearance and increased microalbuminuria.

CONCLUSION

In this endotoxic model, dose-targeted arginine vasopressin infusion increased lipopolysaccharide-induced renal dysfunction without affecting renal blood flow and glomerular function, but with particular disruption of aquaporin-2/V2 receptor networking, consecutive decreased salt and water handling ability. This is in clear contrast with norepinephrine infusion and suggests specific arginine vasopressin-induced "tubular epithelial dysfunction."

Evidence-based medicine in equine critical care

One of the fundamental skills required for practicing evidence-based medicine is the development of a well-built clinical question, which specifies the patient group or problem, intervention, and outcome of interest. For this purpose, various "levels of evidence" have been developed in the human literature, which rank the validity of evidence. Our established conclusions and advice are thus supported by specific "grades of recommendations," which are intended to give an indication of the "strength" of a clinical recommendation. This article was compiled with these principles in mind.

Early use of terlipressin in catecholamine-resistant shock improves cerebral perfusion pressure in severe traumatic brain injury

BACKGROUND

Maintaining adequate cerebral perfusion pressure is an essential aspect in the treatment of severe acute brain injury. To accomplish this therapeutic goal vasopressors are usually required. Vasopressin is an important endogenous stress hormone and the infusion of low-dose vasopressin and terlipressin has been used to reverse severe hypotension.

CASE REPORT

A 14-year-old male patient was admitted to the emergency room after a motorcycle accident. The patient had suffered severe traumatic brain injury, the Glasgow coma score (GCS) was four and there were signs of aspiration of gastric contents. Systemic inflammatory response syndrome and shock refractory to fluid management, norepinephrine and steroid replacement ensued. A terlipressin infusion, as a bolus dose of 1 mg, is associated with the ability to improve cerebral perfusion pressure with concomitant reduction of 80% of norepinephrine doses.

DISCUSSION

The present report illustrates the potential benefits of terlipressin in refractory shock in a patient with severe traumatic brain injury. An increase in cerebral perfusion pressure (CPP) and a huge decrease in the dose of norepinephrine were observed. In the setting of severe brain injury associated with refractory hypotension, terlipressin may improve mean arterial pressure and cerebral perfusion pressure.

CONCLUSION

In the setting of severe brain injury associated with refractory hypotension, terlipressin may have a role as a rescue therapy.

Treatment of severe sepsis: where next? Current and future treatment approaches after the introduction of drotrecogin alfa

Severely septic patients continue to experience excessive morbidity and mortality despite recent advances in critical care. Although significant resources have been invested in new treatments, almost all have failed to improve outcomes. An improved understanding of sepsis pathophysiology, including the complex interactions between inflammatory, coagulation, and fibrinolytic systems, has accelerated the development of novel treatments. Recombinant human activated protein C (rhAPC), or drotrecogin alfa (activated) (DAA), is currently the only US Food and Drug Administration (FDA)-approved medicine for the treatment of severe sepsis, and only in patients with a high risk of death. This review will discuss the treatment of severe sepsis, focusing on recent discoveries and unresolved questions about DAA's optimal use. Increasing pharmacological experience has generated enthusiasm for investigating medicines already approved for other indications as treatments for severe sepsis. Replacement doses of hydrocortisone and vasopressin may reduce mortality and improve hypotension, respectively, in a subgroup of patients with catecholamine-refractory septic shock. In addition to discussing these new indications, this review will detail the provocative preliminary data from four promising treatments, including two novel modalities: antagonizing high mobility group box protein and inhibiting tissue factor (TF). Observational data from the uncontrolled administration of heparin or statins in septic patients will also be reviewed.

Vasopressin: mechanisms of action on the vasculature in health and in septic shock

BACKGROUND

Vasopressin is essential for cardiovascular homeostasis, acting via the kidney to regulate water resorption, on the vasculature to regulate smooth muscle tone, and as a central neurotransmitter, modulating brainstem autonomic function. Although it is released in response to stress or shock states, a relative deficiency of vasopressin has been found in prolonged vasodilatory shock, such as is seen in severe sepsis. In this circumstance, exogenous vasopressin has marked vasopressor effects, even at doses that would not affect blood pressure in healthy individuals. These two findings provide the rationale for the use of vasopressin in the treatment of septic shock. However, despite considerable research attention, the mechanisms for vasopressin deficiency and hypersensitivity in vasodilatory shock remain unclear.

OBJECTIVE

To summarize vasopressin's synthesis, physiologic roles, and regulation and then review the literature describing its vascular receptors and downstream signaling pathways. A discussion of potential mechanisms underlying vasopressin hypersensitivity in septic shock follows, with reference to relevant clinical, in vivo, and in vitro experimental evidence.

DATA SOURCE

Search of the PubMed database (keywords: vasopressin and receptors and/or sepsis or septic shock) for articles published in English before May 2006 and manual review of article bibliographies.

DATA SYNTHESIS AND CONCLUSIONS

The pathophysiologic mechanism underlying vasopressin hypersensitivity in septic shock is probably multifactorial. It is doubtful that this phenomenon is merely the consequence of replacing a deficiency. Changes in vascular receptors or their signaling and/or interactions between vasopressin, nitric oxide, and adenosine triphosphate-dependent potassium channels are likely to be relevant. Further translational research is required to improve our understanding and direct appropriate educated clinical use of vasopressin.

Skin necrosis after a low-dose vasopressin infusion through a central venous catheter for treating septic shock

This is a report on a case of severe skin necrosis in a vasodilatory septic shock patient after the infusion of low-dose vasopressin through a central venous catheter. An 84-year-old male was hospitalized for edema on both legs at Asan Medical Center, Seoul, Korea. On hospital day 8, the patient began to complain of dyspnea and he subsequently developed severe septic shock caused by E. coli. After being transferred to the medical intensive care unit, his hypotension, which was refractory to norepinephrine, was controlled by an infusion of low-dose vasopressin (0.02 unit/min) through a central venous catheter into the right subclavian vein. After the infusion of low-dose vasopressin, severe skin necrosis with bullous changes developed, necessitating discontinuation of the low-dose vasopressin infusion. The patient expired from refractory septic shock. Although low-dose vasopressin can control hypotension in septic shock patients, low-dose vasopressin must be used with caution because ischemic complications such as skin necrosis can develop even with administration through a central venous catheter.

Vasoactive drugs and the gut: is there anything new?

PURPOSE OF REVIEW

Systemic changes in blood pressure and cardiac output induced by pressors and inotropes do not always correlate to improvements in regional perfusion. Since the gut is often referred to as the 'motor' of the systemic inflammatory response syndrome, the impact of vasoactive agents on splanchnic perfusion has theoretical importance. This review will highlight recent studies examining secondary effects of vasoactive agents on intestinal perfusion, metabolism, and barrier function.

RECENT FINDINGS

Norepinephrine has minimal impact on mesenteric blood flow although the combination of norepinephrine and dobutamine increases splanchnic blood flow in sepsis. Dopamine also increases mesenteric blood flow although this may be associated with negative hepatic energy balance at high does. Vasopressin and epinephrine both have negative effects on splanchnic blood flow. Newer inodilators levosimendan and olprinone preferentially improve mesenteric perfusion in animal models.

SUMMARY

Secondary effects of norepinephrine and dopamine on splanchnic perfusion are minor compared with their systemic effects. While vasopressin usage is increasing in the intensive care unit, caution should be used because of its adverse effects on gut perfusion. Experimental agents for the treatment of heart failure have beneficial gut-specific effects although the clinical significance of this is currently limited by their availability.

Early and innovative interventions for severe sepsis and septic shock: taking advantage of a window of opportunity

The pathogenic, diagnostic and therapeutic landscape of sepsis is no longer confined to the intensive care unit: many patients from other portals of entry to care, both outside and within the hospital, progress to severe disease. Approaches that have led to improved outcomes with other diseases (e.g., acute myocardial infarction, stroke and trauma) can now be similarly applied to sepsis. Improved understanding of the pathogenesis of severe sepsis and septic shock has led to the development of new therapies that place importance on early identification and aggressive management. This review emphasizes approaches to the early recognition, diagnosis and therapeutic management of sepsis, giving the clinician the most contemporary and practical approaches with which to treat these patients.

Vasoactive drugs in the intensive care unit

PURPOSE OF THE REVIEW

Vasoactive drugs are the mainstay of hemodynamic management of vasodilatory shock when fluids fail to restore tissue perfusion. In this review, studies published during the past year that increase our understanding of the use of vasoactive drugs in the intensive care unit are discussed.

RECENT FINDINGS

In septic shock, there is no benefit in increasing mean arterial pressure from 65 to 85 mmHg. Norepinephrine did not worsen renal function. Epinephrine induced visceral hypoperfusion and hyperlactatemia, and worsened organ function and survival compared with norepinephrine and vasopressin. There are a number of reports of the safety and efficacy of vasopressin but it is not currently recommended as first line therapy, and if used, should be given as a continuous low dose infusion. Terlipressin is showing promise but decreases cardiac output. Metaraminol is being investigated as an alternative to norepinephrine. Dopamine may improve splanchnic flow mainly by increasing cardiac output. Dobutamine improves oxygen delivery and may improve mesenteric blood flow.

SUMMARY

Over the last 40 years, there have been few controlled clinical trials to guide clinicians on the use of vasoactive drugs of treating shock states. It is not known whether the currently favored combination of norepinephrine and dobutamine is superior to traditional therapy with dopamine. Epinephrine is not recommended as the first-line therapy. The role of vasopressin and terlipressin remains unknown. Three large ongoing clinical trials will be completed soon and the results should clarify the role of these various agents.