Vasopressin pressor effects in critically ill children during evaluation for brain death and organ recovery

Anesthetic Considerations of Organ Procurement After Brain and Cardiac Death: A Narrative Review

Organ donation procedures have become more frequent in the US as the need for transplants is increasing. Defining the anesthesiologist's role in organ donations after brain and cardiac death is important, as is understanding its ethics and practical physiologic and perioperative implications. Despite this, there are few papers specifically addressing the anesthetic management of organ donors. This review summarizes the preoperative, intraoperative, and postmortem considerations for the anesthesiologist involved in organ donation after either brain or cardiac death. A search of the published literature was performed using PubMed, Excerpta Medica dataBASE (EMBASE), and Google Scholar in March of 2022 for articles addressing anesthetic considerations of organ procurement surgeries after brain and cardiac death. This review demonstrates that anesthesiologists play a significant role in the organ procurement process. Their role in the perioperative management of the donor may affect the outcomes of organ transplantation. The gap between the number of organs harvested and the number of patients awaiting organ transplantation remains high despite continued efforts to increase the number of available organs. Perioperative management of organ donors aims at counteracting the associated unique physiologic derangements and targets optimization of oxygenation of the organs intended for procurement. Optimizing care after death can help ensure the viability of organs and the best outcomes for recipients. As organ donation after cardiac death (DCD) becomes more frequent in the US, anesthesiologists should be aware of the DCD classifications of donors and emerging novel perfusion techniques.

Vasopressin Use in the Support of Organ Donors: Physiological Rationale and Review of the Literature

The objective of this review was to depict the physiological and clinical rationale for the use of vasopressin in hemodynamic support of organ donors. After summarizing the physiological, pharmacological concepts and preclinical findings, regarding vasopressin's pathophysiological impacts, we will present the available clinical data.

DATA SOURCES

Detailed search strategies in PubMed, OVID Medline, and EMBASE were undertaken using Medical Subject Headings and Key Words.

STUDY SELECTION

Physiological articles regarding brain death, and preclinical animal and human studies about the use of vasopressin or analogs, as an intervention in organ support for donation, were considered.

DATA EXTRACTION

Two authors independently screened titles, abstracts, and full text of articles to determine eligibility. Data encompassing models, population, methodology, outcomes, and relevant concepts were extracted.

DATA SYNTHESIS

Following brain death, profound reduction in sympathetic outflow is associated with reduced cardiac output, vascular tone, and hemodynamic instability in donors. In addition to reducing catecholamine needs and reversing diabetes insipidus, vasopressin has been shown to limit pulmonary injury and decrease systemic inflammatory response in animals. Several observational studies show the benefit of vasopressin on hemodynamic parameters and catecholamine sparing in donors. Small trials suggest that vasopressin increase organ procurement and have some survival benefit for recipients. However, the risk of bias is overall concerning, and therefore the quality of the evidence is deemed low.

CONCLUSIONS

Despite potential impact on graft outcome and a protective effect through catecholamine support sparing, the benefit of vasopressin use in organ donors is based on low evidence. Well-designed observational and randomized controlled trials are warranted.

Effects of Terlipressin on Management of Hypotensive Brain-Dead Patients Who are Potential Organ Donors: A Retrospective Study

Background: Administration of terlipressin can reverse hypotension in potential organ donors with norepinephrine-resistance. The aim of this study was to determine the effects of terlipressin on the hemodynamics, liver function, and renal function of hypotensive brain-dead patients who were potential organ donors.

Methods: A retrospective study was conducted by using the ICU database of one hospital. 18 patients in a total of 294 brain-dead cases were enrolled and administered terlipressin intravenously. All physiological parameters of recruited patients were obtained at baseline, 24 and 72 h after administration, and immediately before organ procurement.

Results: Terlipressin induced significant increases in mean arterial pressure (MAP) from 69.56 ± 10.68 mm Hg (baseline) to 101.82 ± 19.27 mm Hg (immediately before organ procurement) and systolic blood pressure (SBP) from 89.78 ± 8.53 mm Hg (baseline) to 133.42 ± 26.11 mm Hg (immediately before organ procurement) in all patients. The increases in MAP were accompanied by significant decreases in heart rate (HR) from 113.56 ± 28.43 bpm (baseline) to 83.89 ± 11.70 bpm (immediately before organ procurement), which resulted in the decrease of norepinephrine dose over time from 0.8 ± 0.2 μg/kg/min (baseline) to 0.09 ± 0.02 μg/kg/min (immediately before organ procurement). There were no changes in central venous pressure, liver function including aspartate aminotransferase (AST), alanine aminotransferase (ALT), and bilirubin. Renal function, assessed by serum creatinine (SCr), urine output (UOP), creatinine clearance rate (CCr), and estimated glomerular filtration rate (eGFR), improved significantly.

Conclusion: Our analysis of brain-dead patients with hypotension indicates that administration of terlipressin can significantly increases MAP, SBP, UOP, CCr, and eGFR, while decreases HR and Scr. Terlipressin appears to help maintain hemodynamic stability, reduce vasoactive support, and improve renal function.

Brazilian guidelines for the management of brain-dead potential organ donors. The task force of the AMIB, ABTO, BRICNet, and the General Coordination of the National Transplant System

OBJECTIVE

To contribute to updating the recommendations for brain-dead potential organ donor management.

METHOD

A group of 27 experts, including intensivists, transplant coordinators, transplant surgeons, and epidemiologists, joined a task force formed by the General Coordination Office of the National Transplant System/Brazilian Ministry of Health (CGSNT-MS), the Brazilian Association of Intensive Care Medicine (AMIB), the Brazilian Association of Organ Transplantation (ABTO), and the Brazilian Research in Intensive Care Network (BRICNet). The questions were developed within the scope of the 2011 Brazilian Guidelines for Management of Adult Potential Multiple-Organ Deceased Donors. The topics were divided into mechanical ventilation, hemodynamic support, endocrine-metabolic management, infection, body temperature, blood transfusion, and use of checklists. The outcomes considered for decision-making were cardiac arrest, number of organs recovered or transplanted per donor, and graft function/survival. Rapid systematic reviews were conducted, and the quality of evidence of the recommendations was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. Two expert panels were held in November 2016 and February 2017 to classify the recommendations. A systematic review update was performed in June 2020, and the recommendations were reviewed through a Delphi process with the panelists between June and July 2020.

RESULTS

A total of 19 recommendations were drawn from the expert panel. Of these, 7 were classified as strong (lung-protective ventilation strategy, vasopressors and combining arginine vasopressin to control blood pressure, antidiuretic hormones to control polyuria, serum potassium and magnesium control, and antibiotic use), 11 as weak (alveolar recruitment maneuvers, low-dose dopamine, low-dose corticosteroids, thyroid hormones, glycemic and serum sodium control, nutritional support, body temperature control or hypothermia, red blood cell transfusion, and goal-directed protocols), and 1 was considered a good clinical practice (volemic expansion).

CONCLUSION

Despite the agreement among panel members on most recommendations, the grade of recommendation was mostly weak. The observed lack of robust evidence on the topic highlights the importance of the present guideline to improve the management of brain-dead potential organ donors.

Management of the Pediatric Organ Donor

Management of the pediatric organ donor necessitates understanding the physiologic changes that occur preceding and after death determination. Recognizing these changes allows application of the therapeutic strategies designed to optimize hemodynamics and metabolic state to allow for preservation of end-organ function for maximal organ recovery and minimal damage to the donor grafts. The pediatric pharmacist serves as the medication expert and may collaborate with the organ procurement organizations for provision of pharmacologic hemodynamic support, hormone replacement therapy, antimicrobials, and nutrition for the pediatric organ donor.

Variation in Pediatric Organ Donor Management Practices Among US Organ Procurement Organizations

INTRODUCTION

Reports of actual pediatric organ donor management practice among US organ procurement organizations are sparse, and the use of standardized management guidelines is unknown. A recent consensus statement from the Society of Critical Care Medicine, the American College of Chest Physicians, and the Association of Organ Procurement Organizations offers guidelines for the management of the pediatric organ donor.

RESEARCH QUESTION

To describe the use of guidelines and routine practices in the management of the pediatric organ donor with respect to hemodynamics, lung and ventilator management, fluid and electrolytes, hormonal replacement therapy, the use of blood products, thermoregulation, and prophylactic antibiotics.

DESIGN

Cross-sectional observational study using a survey and follow-up telephone interview with respondents from all 58 US organ procurement organizations.

RESULTS

All 58 US Organ Procurement Organizations participated. A majority employed written guidelines for the management of pediatric donor hemodynamics, thermoregulation, fluids, and electrolytes. Management of blood products, the lung, and mechanical ventilation were less commonly committed to written guidelines, but common practices were described. All used various forms of hormonal replacement therapy and the majority administered empiric antibiotic therapy. Wide variation was observed in the management of the lung, mechanical ventilation, and glycemic control.

DISCUSSION

Most OPOs used forms of standardized donor management for the pediatric organ donor although variation in the content of that management exists. Barriers to an evidence-based approach to the pediatric donor need to be determined and addressed.

Vasopressin Bolus Protocol Compared to Desmopressin (DDAVP) for Managing Acute, Postoperative Central Diabetes Insipidus and Hypovolemic Shock

Introduction. Management of postoperative central diabetes insipidus (DI) can be challenging from changes in volume status and serum sodium levels. We report a case successfully using a dilute vasopressin bolus protocol in managing hypovolemic shock in acute, postoperative, central DI. Case Report. Patient presented after bifrontal decompressive craniotomy for severe traumatic brain injury. He developed increased urine output resulting in hypovolemia and hypernatremia. He was resuscitated with intravenous fluids including a dilute vasopressin bolus protocol. This protocol consisted of 1 unit of vasopressin in 1 liter of 0.45% normal saline. This protocol was given in boluses based on the formula: urine output minus one hundred. Initial serum sodium was 148 mmol/L, and one-hour urine output was 1 liter. After 48 hours, he transitioned to 1-desamino-8-D-arginine vasopressin (DDAVP). Pre-DDAVP serum sodium was 149 mmol/L and one-hour urine output 320 cc. Comparing the bolus protocol to the DDAVP protocol, the average sodium was 143.8 ± 3.2 and 149.6 ± 3.2 mmol/L (p = 0.0001), average urine output was 433.2 ± 354.4 and 422.3 ± 276.0 cc/hr (p = 0.90), and average specific gravity was 1.019 ± 0.009 and 1.016 ± 0.01 (p = 0.42), respectively. Conclusion. A protocol using dilute vasopressin bolus can be an alternative for managing acute, central DI postoperatively, particularly in setting of hypovolemic shock resulting in a consistent control of serum sodium.

Vasopressin in Pediatric Critical Care

Vasopressin is a unique hormone with complex receptor physiology and numerous physiologic functions beyond its well-known vascular actions and osmoregulation. While vasopressin has in the past been primarily used in the management of diabetes insipidus and acute gastrointestinal bleeding, an increased understanding of the physiology of refractory shock, and the role of vasopressin in maintaining cardiovascular homeostasis prompted a renewed interest in the therapeutic roles for this hormone in the critical care setting. Identifying vasopressin-deficient individuals for the purposes of assessing responsiveness to exogenous hormone and prognosticating outcome has expanded research into the evaluation of vasopressin and its precursor, copeptin as useful biomarkers. This review summarizes the current evidence for vasopressin in critically ill children, with a specific focus on its use in the management of shock. We outline important considerations and current guidelines, when considering the use of vasopressin or its analogues in the pediatric critical care setting.

Cardiac organ donor management

There is a critical shortage of donor organs. According to the United Network for Organ Sharing (UNOS), 20% of organs are discarded after procurement. Many of these may be potentially salvageable. Brain death is particularly detrimental to cardiac function. The initial sympathetic storm can produce direct myocardial injury. The ensuing spinal shock reduces global oxygen delivery. There is a change to anaerobic metabolism due to global mitochondrial dysfunction. Diabetes insipidus worsens hypovolemia and thyroid deficiency impairs cardiac function. Inadequate replacement of blood loss from trauma and coagulopathy worsens anemia and oxygen delivery. In the mid-1990s, the Papworth Hospital group in the UK advocated early invasive hemodynamic monitoring and administration of a ‘hormonal cocktail’, consisting of triiodothyronine (T3), vasopressin, methylprednisolone and insulin. This has been widely accepted and is endorsed by UNOS. Ventricular function, volume status and adequacy of resuscitation should be guided by invasive monitoring and serial echocardiography. Dopamine or epinephrine is used for inotropic support. If hypotension persists, vasopressin should be added which may allow reduction of inotropes. Donor lung function and ventilation should be optimized. Recently, two large retrospective studies have shown that, with aggressive pharmacological and hormonal resuscitation, a significant increase in the number and quality of organs harvested can be achieved.

Vasopressin: Applications in Clinical Practice

Arginine vasopressin is a peptide produced in the posterior pituitary whose primary physiologic role is fluid homeostasis. Recent investigations have demonstrated a therapeutic role for arginine vasopressin in adult cardiac arrest as well as adult and pediatric vasodilatory shock. We review the physiology of arginine vasopressin and examine the supporting data behind the developing clinical applications of this naturally produced peptide.

Endocrine Considerations of the Pediatric Organ Donor

Patients determined to be neurologically deceased exhibit potentially harmful changes in various endocrine pathways due to disruptions of the body's neurohormonal control mechanisms. These deviations from endocrine homeostasis lead to hemodynamic, metabolic, and immunologic aberrations that are associated with reduced graft procurement and function for the purposes of organ donation. Existing literature has attempted to describe the pathophysiology that associates disruptions in endocrine pathways with organ dysfunction, both to increase understanding and to identify strategies to support the donor. For example, diabetes insipidus due to arginine vasopressin deficiency is commonly encountered, and should be anticipated. The significance of abnormalities in other pathways such as those involving cortisol and thyroid hormone is less established; however, there is increasing support for treating potential organ donors with combined hormonal therapies. While there are published documents aimed at guiding management of organ donors in general, many controversies exist and pediatric-specific literature is scarce. This article aims to review several of the important endocrine-specific aspects of managing the neurologically deceased organ donor, with an emphasis on pediatrics where information is available.

Management of the Potential Organ Donor in the ICU: Society of Critical Care Medicine/American College of Chest Physicians/Association of Organ Procurement Organizations Consensus Statement

This document was developed through the collaborative efforts of the Society of Critical Care Medicine, the American College of Chest Physicians, and the Association of Organ Procurement Organizations. Under the auspices of these societies, a multidisciplinary, multi-institutional task force was convened, incorporating expertise in critical care medicine, organ donor management, and transplantation. Members of the task force were divided into 13 subcommittees, each focused on one of the following general or organ-specific areas: death determination using neurologic criteria, donation after circulatory death determination, authorization process, general contraindications to donation, hemodynamic management, endocrine dysfunction and hormone replacement therapy, pediatric donor management, cardiac donation, lung donation, liver donation, kidney donation, small bowel donation, and pancreas donation. Subcommittees were charged with generating a series of management-related questions related to their topic. For each question, subcommittees provided a summary of relevant literature and specific recommendations. The specific recommendations were approved by all members of the task force and then assembled into a complete document. Because the available literature was overwhelmingly comprised of observational studies and case series, representing low-quality evidence, a decision was made that the document would assume the form of a consensus statement rather than a formally graded guideline. The goal of this document is to provide critical care practitioners with essential information and practical recommendations related to management of the potential organ donor, based on the available literature and expert consensus.

Modified brain death model for rats

OBJECTIVES

Experimental animal models of brain death that mimic human conditions may be useful for investigating novel strategies that increase quality and quantity of organs for transplant.

MATERIALS AND METHODS

Brain death was induced by increasing intracranial pressure by inflating an intracranial placed balloon catheter. Brain death was confirmed by flatline electroencephalogram, physical signs of apnea, and absence of brain stem reflexes. Donor management was done after brain death. Intracranial pressure and physiologic variables were continually monitored during 9 hours' follow-up.

RESULTS

Ninety percent of brain dead animals showed typical signs of brain death such as diabetes insipidus, hypertensive, and hypotensive periods. Donor care was performed for 9 hours after brain death, and the mean arterial pressure was maintained above 60 mm Hg.

CONCLUSIONS

We conclude that the rat model of brain death can be performed in a standardized, reproducible, and successful way.

Establishing a brain-death donor model in pigs

INTRODUCTION

An animal model that imitates human conditions might be useful not only to monitor pathomechanisms of brain death and biochemical cascades but also to investigate novel strategies to ameliorate organ quality and functionality after multiorgan donation.

METHODS

Brain death was induced in 15 pigs by inserting a catheter into the intracranial space after trephination of the skull and augmenting intracranial pressure until brain stem herniation. Intracranial pressure was monitored continuously; after 60 minutes, brain death diagnostics were performed by a neurologist including electroencephalogram (EEG) and clinical examinations. Clinical examinations included testing of brain stem reflexes as well as apnoe testing; then intensive donor care was performed according to standard guidelines until 24 hours after confirmation of brain death. Intensive donor care was performed according to standard guidelines for 24 hours after brain death.

RESULTS

Sixty minutes after brain-death induction, neurological examination and EEG examination confirmed brain death. Intracranial pressure increased continuously, remaining stable after the occurrence of brain death. All 15 animals showed typical signs of brain death such as diabetes insipidus, hypertensive and hypotensive periods, as well as tachycardia. All symptoms were treated with standard medications. After 24 hours of brain death we performed successful multiorgan retrieval.

DISCUSSION

Brain death can be induced in a pig model by inserting a catheter after trephination of the skull. According to standard guidelines the brain-death diagnosis was established by a flat-line EEG, which occurred in all animals at 60 minutes after induction.

Critical care of the potential organ donor

Organ transplantation represents one of the great success stories of 20th century medicine. However, its continued success is greatly limited by the shortage of donor organs. This has led to an increased focus within the critical care community on optimal identification and management of the potential organ donor. The multi-organ donor can represent one of the most complex intensive care patients, with numerous competing physiological priorities. However, appropriate management of the donor not only increases the number of organs that can be successfully donated but has long-term implications for the outcomes of multiple recipients. This review outlines current understandings of the physiological derangements seen in the organ donor and evaluates the available evidence for management strategies designed to optimize donation potential and organ recovery. Finally, emerging management strategies for the potential donor are discussed within the current ethical and legal frameworks permitting donation after both brain and circulatory death.

Terlipressin in brain-death donors

BACKGROUND

Metabolic management of brain-death organ donors includes correction of the hormonal perturbations that occur after cerebral death and impair circulatory function. Vasopressin is a hormone secreted by the posterior pituitary gland, which contributes to maintain systemic blood pressure by regulating urine secretion and small arteriole tonus. During brain death, the pituitary gland is damaged and hormone secretion rapidly ceases. Low-dose vasopressin increases systemic blood pressure and decreases the need for catecholamines in brain-dead organ donors but it is not available in many countries. Terlipressin is a synthetic analog of vasopressin characterized by greater selectivity for the V1 receptor than vasopressin. To date, the efficacy of terlipressin as a pressor agent in humans has been reported in a few studies.

METHOD

Pharmacology and literature about the use of terlipressin in shock and in particularly in neurogenic shock following brain death is summarized and our personal experience is reported.

RESULTS AND CONCLUSION

Terlipressin is helpful in controlling severe hypotension; its use allowed to reduce the infusion rate of norepinephrine about 50% in two of three brain-death organ donors, but there are not yet enough data to define its therapeutic range and incidence of collateral effects on the grafts.

Therapeutic applications of vasopressin in pediatric patients

CONTEXT

Reports of successful use of vasopressin in various shock states and cardiac arrest has lead to the emergence of vasopressin therapy as a potentially major advancement in the management of critically ill children.

OBJECTIVE

To provide an overview of physiology of vasopressin, rationale of its use and dose schedule in different disease states with special focus on recent advances in the therapeutic applications of vasopressin.

DATA SOURCE

MEDLINE search (1966-September 2011) using terms vasopressin, terlipressin, arginine-vasopressin, shock, septic shock, vasodilatory shock, cardiac arrest, and resuscitation for reports on vasopressin/terlipressin use in children and manual review of article bibliographies. Search was restricted to human studies. Randomized controlled trials, cohort studies, evaluation studies, case series, and case reports on vasopressin/terlipressin use in children (preterm neonates to 21 years of age) were included. Outcome measures were analysed using following clinical questions: indication, dose and duration of vasopressin/terlipressin use, main effects especially on systemic blood pressure, catecholamine requirement, urine output, serum lactate, adverse effects, and mortality.

RESULTS

51 reports on vasopressin (30 reports) and terlipressin (21 reports) use in pediatric population were identified. A total of 602 patients received vasopressin/terlipressin as vasopressors in various catecholamine-resistant states (septic - 176, post-cardiotomy - 136, other vasodilatory/mixed shock - 199, and cardiac arrest - 101). Commonly reported responses include rapid improvement in systemic blood pressure, decline in concurrent catecholamine requirement, and increase in urine output; despite these effects, the mortality rates remained high.

CONCLUSION

In view of the limited clinical experience, and paucity of randomized controlled trials evaluating these drugs in pediatric population, currently no definitive recommendations on vasopressin/terlipressin use can be laid down. Nevertheless, available clinical data supports the use of vasopressin in critically ill children as a rescue therapy in refractory shock and cardiac arrest.

Brain death and its influence on the lungs of the donor: how is it prevented?

The need for lung grafts is currently greater than ever. Unfortunately, the availability of grafts is insufficient for this demand. So we are forced to request organs for transplantation in the "waste bin." One possible solution to this problem may be the use of grafts from brain-dead patients. Sadly brain death is followed by devastating hemodynamic, inflammatory, and neurohumoral reactions in the potential donor which not only inflict direct damage, but also induce activation of the immune system which can cause rejection or even graft failure. Therefore, various groups have examined measures to prevent this outcome. In this review, we attempt to reconstruct the events that follow brain death, suggesting an algorithm to prevent a brain-dead patient's lungs from further damage. Finally, we are proposing potential measures of graft's protection of further investigation.

Critical care management of potential organ donors: our current standard

Caring for a brain dead potential organ donor requires a shift in critical care from the extensive treatment of increased intracranial pressure towards strategies to maintain donor organ function. Suboptimal, unstandardized critical care management of organ donors, however, is one of the main reasons for insufficient organ procurement. The pathophysiological changes following brain death entail a high incidence of complications including hemodynamic instability, endocrine and metabolic disturbances, and disruption of internal homeostasis that jeopardize potentially transplantable organs. Strategies for the management of organ donors exist and consist of the normalization of donor physiology. This has resulted in standardized efforts to improve the critical care delivered to potential organ donors, increasing not only the number, but also the quality of suitable organs and aiming at an optimal outcome for the recipients. In this review, we discuss the pathophysiological changes associated with brain death and present the current guidelines at our department, which are optimized based on available literature.

Vasopressin in pediatric shock and cardiac arrest

OBJECTIVE

To review the physiology and the published literature on the role of vasopressin in shock in children.

DATA SOURCE

We searched MEDLINE (1966-2007), EMBASE (1980-2007), and the Cochrane Library, using the terms vasopressin, terlipressin, and shock and synonyms or related terms for relevant studies in pediatrics. We searched the online ISRCTN-Current Controlled Trials registry for ongoing trials. We reviewed the reference lists of all identified studies and reviews as well as personal files to identify other published studies.

RESULTS

Beneficial effects have been reported in vasodilatory shock and asystolic cardiac arrest in adults. Solid evidence for vasopressin use in children is scant. Observational studies have reported an improvement in blood pressure and rapid weaning off catecholamines during administration of low-dose vasopressin. Dosing in children is extrapolated from adult studies.

CONCLUSIONS

Vasopressin offers promise in shock and cardiac arrest in children. However, in view of the limited experience with vasopressin, it should be used with caution. Results of a double-blind, randomized controlled trial in children with vasodilatory shock will be available soon.

Hemodynamic resuscitation with arginine vasopressin reduces lung injury after brain death in the transplant donor

BACKGROUND

The autonomic storm accompanying brain death leads to neurogenic pulmonary edema and triggers development of systemic and pulmonary inflammatory responses. Neurogenic vasoplegia exacerbates the pulmonary injury caused by brain death and primes the lung for ischemia reperfusion injury and primary graft dysfunction in the recipient. Donor resuscitation with norepinephrine ameliorates the inflammatory response to brain death, however norepinephrine has deleterious effects, particularly on the heart. We tested the hypothesis that arginine vasopressin is a suitable alternative to norepinephrine in managing the hypotensive brain dead donor.

METHODS

Brain death was induced in Wistar rats by intracranial balloon inflation. Pulmonary capillary leak was estimated using radioiodinated albumin. Development of pulmonary edema was assessed by measurement of wet and dry lung weights. Cell surface expression of CD11b/CD18 by neutrophils was determined using flow cytometry. Enzyme-linked immunosorbent assays were used to measure the levels of TNFalpha, IL-1beta, CINC-1, and CINC-3 in serum and bronchoalveolar lavage. Quantitative reverse-transcription polymerase chain reaction was used to determine the expression of cytokine mRNA (IL-1beta, CINC-1 and CINC-3) in lung tissue.

RESULTS

There was a significant increase in pulmonary capillary permeability, wet/dry lung weight ratios, neutrophil integrin expression and pro-inflammatory cytokines in serum (TNFalpha, IL-1beta, CINC-1 and CINC-3), bronchoalveolar lavage (TNFalpha and IL-1beta) and lung tissue (IL-1beta and CINC-1) in braindead animals compared to controls. Correction of neurogenic hypotension with either arginine vasopressin or norepinephrine limits edema, reduces pulmonary capillary leak, and modulates systemic and pulmonary inflammatory responses to brain death.

CONCLUSIONS

Arginine vasopressin and norepinephrine are equally effective in treating the hypotensive pulmonary donor in this rodent model.

Impact of terlipressin on renal graft function

To assess the effect of a bolus of terlipressin in brain-dead donors with shock refractory to norepinephrine, a retrospective study was conducted in a 16-bed intensive care unit of a university hospital. Twenty brain-dead donors were treated with norepinephrine within the study period. Nine of these donors developed persisting hypotension (MAP < 65 mmHg) not responding to fluid loading and high dose of norepinephrine. They were then treated with a single bolus of terlipressin (1 mg). This resulted in a MAP rise from 58 +/- 10 to 93 +/- 20 mmHg (P = 0.009). One month after transplantation, no differences were observed in serum creatinine levels of the recipients who received a renal transplant extracted from donors responding or not to norepinephrine (138 +/- 43 vs. 137 +/- 43 microM; P = 0.95). The liver function was similar in both groups. Within the limitations of this study, a single bolus of terlipressin in norepinephrine-resistant vasodilatory shock donors does not affect the renal and liver graft quality in the recipients.

Recent developments in the pharmacologic approach to pediatric critical care

PURPOSE OF REVIEW

There is new information supporting a resurgence of targeted use of older medications. These therapies include hydrocortisone and vasopressin. In addition to these older drugs, newer drugs, drotrecogin alpha (activated protein C) and activated factor VII concentrate (NovoSeven), have been used and may improve outcome in the treatment of critically ill patients. This review summarizes the recent experience of these agents in the adult and pediatric critically ill populations.

RECENT FINDINGS

Preliminary findings are encouraging in selected septic children and adults for human recombinant activated protein C and protein C concentrate. Plasma vasopressin levels in pediatric septic shock and their importance have not yet been adequately studied. Recent evidence supports physiologic replacement of corticosteroids in specific adult populations. Further investigations are warranted to establish the role of activated factor VIIa in the treatment of critically ill children.

SUMMARY

The limited experience of protein C manipulation in critically ill septic pediatric patients makes it difficult to define its role in their care. Although it has been associated with improved outcomes, its risk profile warrants judicious use. Further prospective pediatric clinical trials are needed to define the role of vasopressin in the treatment of pediatric shock and cardiac arrest. The role of corticosteroids in the treatment of septic shock in adults and children continues to be debated. Activated factor VIIa administration to adult and pediatric patients without primary bleeding disorders has been increasing. Further investigations are warranted to establish the role of activated factor VIIa in the treatment of critically ill children.

Medical management to optimize donor organ potential: review of the literature

PURPOSE

Over the past two decades, the demand for donor organs continues to outpace the number of organs available for transplantation. Parallel with this has been a change in the demographics of organ donors with an increase in older donors and donors with marginal organs as a proportion of the total organ donor pool. Consequently, efforts have been made to improve the medical care delivered to potential organ donors to improve the conversion rate and graft survival of available organs. The purpose of this literature review is to provide updated recommendations for the contemporary management of organ donors after the neurological determination of death in order to maximize the probability of recipient graft survival.

SOURCES

A comprehensive review of the literature obtained through searches of MEDLINE/PubMed, and personal reference files.

PRINCIPAL FINDINGS

Contemporary management of the organ donor after neurological determination of death includes therapies to prevent the detrimental effects of the autonomic storm, the use of invasive hemodynamic monitoring and aggressive respiratory therapy including therapeutic bronchoscopy in marginal heart and lung donors, and the use of hormonal therapy including vasopressin, corticosteroids, triiodothyronine or thyroxine, and insulin for the pituitary failure and inflammation seen in brain dead organ donors. The importance of normalizing donor physiology to optimize all available organs is stressed.

CONCLUSION

Aggressive hemodynamic and respiratory management of solid organ donors, coupled with the use of hormonal therapy improves the rate of conversion and graft survival in solid organ recipients.

INTRAVENOUS ARGININE VASOPRESSIN IN CRITICALLY ILL CHILDREN: IS IT BENEFICIAL?

Arginine-vasopressin (AVP) may be more effective than epinephrine in shock states and as an end-of-life salvage maneuver. However, there is only limited experience using AVP in children. Our study aim was to evaluate the effect of AVP administration on hemodynamic and ventilatory parameters in critically ill children. Eight critically ill children (1 month to 12 years old) were treated with AVP during the years 2000-2001. Two patients had had head trauma, and six had surgical correction of congenital heart disease. All patients suffered severe septic or cardiogenic shock with a low cardiac output state and were considered to be near death. AVP was administered continuously at a dose of 0.0003-0.002 U/kg/min. Hemodynamic and ventilatory parameters and vasopressor doses were compared before and after AVP initiation. One patient survived with a good neurologic outcome. Seven patients succumbed while receiving AVP. Systolic and diastolic blood pressure increased significantly (P < 0.03) following AVP initiation. The epinephrine requirement decreased from 2.3 to 1.7 microg/kg/min. Blood gases improved with a significant (P < 0.05) increase of PaO2. Oxygenation index and PaO2/FiO2 ratio improved significantly, and ventilatory support requirements and positive inspiratory pressure (PIP) decreased significantly. Despite a significant improvement in hemodynamic and ventilatory support parameters, survival to hospital discharge was not achieved when AVP was used in critically ill pediatric patients. We hypothesize that earlier administration of AVP may be more beneficial.

Evaluation of coma and brain death

Coma is a nonspecific sign of widespread central nervous system impairment resulting from various metabolic and structural etiologies. The rapid recognition of this neurologic emergency and results from the history, physical examination, and early investigative studies are key to the identification and treatment of its underlying cause. The prognosis for recovery depends greatly on the underlying etiology as well as on its optimal treatment, which seeks to preserve neurologic function and maximize the potential for recovery by reversing the primary cause of brain injury, if known, and preventing secondary brain injury from anoxia, ischemia, hypoglycemia, cerebral edema, seizures, infections, and electrolyte and temperature disturbances. Brain death must be diagnosed with similar care and precision, and families approached compassionately about the diagnosis and their decisions regarding organ donation.

Critical Care Pharmacy in Donor Management

Significant systemic changes occur following neurologic insult and subsequent brain death. If left untreated, the hemodynamic instability and neuroendocrine alterations that ensue may significantly affect the quality of the donor organs, and contribute to posttransplant allograft dysfunction. A number of pharmacologic interventions are often implemented in an attempt to stabilize donor hemodynamics and optimize organ perfusion, thereby increasing the number and quality of cadaveric donor organs available for transplantation. This review provides a summary of these interventions, with an emphasis placed on hormonal resuscitation, which involves utilizing such agents as thyroxin, vasopressin, insulin, and corticosteroids.

Terlipressin bolus induces systemic vasoconstriction in septic shock

OBJECTIVE

To report the use of a synthetic, long-acting, vasopressin analog, terlipressin, as an effective vasoconstrictor in septic shock.

DESIGN

Case report.

SETTING

A 22-bed pediatric intensive care unit in a tertiary referral center.

PATIENT

An 11-yr-old male with multiple-organism Gram-negative septic shock with high normal cardiac output as assessed by pulse contour analysis and low systemic vascular resistance despite norepinephrine infusion.

INTERVENTION

Two peripherally administered doses of terlipressin (0.5 mg).

MEASUREMENTS AND MAIN RESULTS

Each dose of terlipressin was associated with a rapid increase in systemic vascular resistance, despite weaning and discontinuation of norepinephrine infusion from 0.15 microg.kg(-1).min(-1) lasting approximately 6 hrs.

CONCLUSION

Terlipressin may be useful for sepsis-induced vasodilation.

Management of vasodilatory shock: defining the role of arginine vasopressin

The rationale for an arginine vasopressin (argipressin) infusion was put forward after it was discovered that patients in shock states might have an endogenous arginine vasopressin deficiency. Subsequently, several investigations impressively demonstrated that arginine vasopressin can successfully stabilise haemodynamics even in advanced vasodilatory shock. We report on physiological and pharmacological aspects of arginine vasopressin, and summarise current clinical knowledge on employing a continuous arginine vasopressin infusion in critically ill patients with catecholamine-resistant vasodilatory shock of different aetiologies. In view of presented experimental evidence and current clinical experience, a continuous arginine vasopressin infusion of approximately 2 to approximately 6 IU/h can be considered as a supplemental strategy to vasopressor catecholamines in order to preserve cardiocirculatory homeostasis in patients with advanced vasodilatory shock. Because data on adverse effects are still limited, arginine vasopressin should be reserved for patients in whom adequate haemodynamic stabilisation cannot be achieved with conventional vasopressor therapy or who have obvious adverse effects of catecholamines that result in further significant haemodynamic deterioration. For the same reasons, arginine vasopressin should not be used as a single, alternative vasopressor agent instead of catecholamine vasopressors. Future prospective studies will be necessary to define the exact role of arginine vasopressin in the therapy of vasodilatory shock.

Consensus conference report: maximizing use of organs recovered from the cadaver donor: cardiac recommendations, March 28-29, 2001, Crystal City, Va

The shortage of available donor hearts continues to limit cardiac transplantation. For this reason, strict criteria have limited the number of patients placed on the US waiting list to approximately 6000 to 8000 per year. Because the number of available donor hearts has not increased beyond approximately 2500 per year, the transplant waiting list mortality rate remains substantial. Suboptimal and variable utilization of donor hearts has compounded the problem in the United States. In 1999, the average donor yield from 55 US regions was 39%, ranging from 19% to 62%. This report provides the detailed cardiac recommendations from the conference on "Maximizing Use of Organs Recovered From the Cadaver Donor" held March 28 to 29, 2001, in Crystal City, Va. The specific objective of the report is to provide recommendations to improve the evaluation and successful utilization of potential cardiac donors. The report describes the accuracy of current techniques such as echocardiography in the assessment of donor heart function before recovery and the impact of these data on donor yield. The rationale for and specific details of a donor-management pathway that uses pulmonary artery catheterization and hormonal resuscitation are provided. Administrative recommendations such as enhanced communication strategies among transplant centers and organ-procurement organizations, financial incentives for organ recovery, and expansion of donor database fields for research are also described.

Brain death does not affect hepatic allograft function and survival after orthotopic transplantation in a canine model

BACKGROUND

Brain death has been shown to decrease graft function and survival in rodent models. The aim of this study was to evaluate how brain death affects graft viability in the donor and liver tolerance to cold preservation as assessed by survival in a canine transplant model.

METHODS

Beagle dogs were used for the study. Non-brain dead (BD) donors served as controls. Brain death was induced by sudden inflation of a subdural balloon catheter with continuous monitoring of arterial blood pressure and electroencephalographic activity. Sixteen hours after confirmation of brain death, liver grafts were retrieved. All livers were flushed in situ and preserved for 24 hr in cold University of Wisconsin solution before transplantation. Recipient survival rates, serum hepatic enzyme levels, coagulation, and metabolic parameters of the recipients were analyzed.

RESULTS

No significant changes were observed in serum aminotransferases (alanine and aspartate transaminases) and lactate dehydrogenase levels in the BD donor. After preservation, control (n=6) and BD livers (n=5) showed full functional recovery after transplant with 100% survival in both groups at day 7. There was no significant difference in peak serum alanine, aspartate transaminases, and lactate dehydrogenase after transplantation in recipients who received a liver from BD donor compared to control group. BD livers were functionally as capable as control livers in correcting metabolic acidosis during the first 24 hr posttransplantation. Coagulation profiles (index normalized ratio, activated partial thromboplastin time) after reperfusion were similar between groups.

CONCLUSION

In contrast to previous reports in rodent models, our study shows that brain death does not cause significant liver dysfunction in the donor before organ removal. Donor brain death and prolonged liver graft preservation do not interact significantly to impair liver function and survival after transplantation.

Beneficial effects of vasopressin in prolonged pediatric cardiac arrest: a case series

Children who suffer cardiac arrest have a poor prognosis. Based on laboratory animal studies and clinical data in adults, vasopressin is an exciting new vasopressor treatment modality during cardiopulmonary resuscitation (CPR). In particular, vasopressin has resulted in short term resuscitation benefits as a "rescue" pressor agent in the setting of prolonged out-of-hospital CPR for ventricular fibrillation in adults. This retrospective series presents the first evidence for resuscitation benefit of bolus vasopressin therapy in the specific setting of pediatric cardiac arrest. All episodes of CPR initiated in a 120-bed tertiary care children's hospital over a three-year period (1997-2000) were reviewed. Four children in the pediatric ICU received vasopressin boluses as rescue therapy during six cardiac arrest events, following failure of conventional CPR, advanced life support, and epinephrine vasopressor therapy. Return of spontaneous circulation for greater than 60 min occurred in three of four patients (75%) and in four of six CPR events (66%) following vasopressin administration. Two of four vasopressin recipients survived >24 h; one survived to hospital discharge and one had withdrawal of supportive therapies following family discussion. Our observations are AHA level 5 (retrospective case series) evidence that vasopressin administration may be beneficial during prolonged pediatric cardiac arrest. Such reports should pave the way for prospective clinical trials comparing vasopressor medications in the setting of pediatric cardiac arrest.