Regional anesthesia in austere environments

Military anesthesiologists must master the complexities of modern anesthesia at home, like their civilian counterparts, and also be prepared to provide effective, safe anesthesia in the chaotic and austere environment of the modern battlefield. This article describes the Army Regional Anesthesia Initiative and Operational Anesthesia Rotation programs designed to facilitate this difficult goal.     

Acute kidney injury

Acute kidney injury (AKI) is defined as an abrupt decline in the glomerular filtration rate with accumulation of nitrogenous waste products and the inability to maintain fluid and electrolyte homeostasis. Occurring in 7% of all hospitalized patients and 28% to 35% of those in intensive care units, AKI increases hospital mortality. Early evaluation should include differentiating prerenal and postrenal components from intrinsic renal disease. Biological markers can give early warning of AKI and assist with differential diagnosis and assessment of prognosis. The most effective preventive measure is to maintain adequate circulation and cardiac output, avoiding ischemia- or nephrotoxin-induced injury. To that end, patients and situations of risk must be identified, hemodynamics and diuresis monitored, hypovolemia reversed, and nephrotoxins avoided. Protective agents such as sodium bicarbonate, mannitol, prostagiandins, calcium channel blockers, N-acetyl-L-cysteine, sodium deoxycholate, allopurinol, and pentoxifylline should be used. Treatment includes the elimination of prerenal and postrenal causes of AKI; adjustment of doses according to renal function; avoidance of both overhydration and low arterial pressure; maintenance of electrolytic balance, avoiding hyperkalemia and correcting hyperglycemia; and nutritional support, assuring adequate protein intake. For severe AKI, several modalities of renal replacement therapy, differentiated by mechanism and duration, are available. Timing--neither the best moment to start dialysis nor the optimal duration--has been not established. Early detection of AKI is necessary for preventing progression and starting renal replacement therapy at adjusted doses that reflect metabolic requirements.     

Acute kidney injury in children

Acute kidney injury (AKI) (previously called acute renal failure) is characterized by a reversible increase in the blood concentration of creatinine and nitrogenous waste products and by the inability of the kidney to regulate fluid and electrolyte homeostasis appropriately. The incidence of AKI in children appears to be increasing, and the etiology of AKI over the past decades has shifted from primary renal disease to multifactorial causes, particularly in hospitalized children. Genetic factors may predispose some children to AKI. Renal injury can be divided into pre-renal failure, intrinsic renal disease including vascular insults, and obstructive uropathies. The pathophysiology of hypoxia/ischemia-induced AKI is not well understood, but significant progress in elucidating the cellular, biochemical and molecular events has been made over the past several years. The history, physical examination, and laboratory studies, including urinalysis and radiographic studies, can establish the likely cause(s) of AKI. Many interventions such as ‘renal-dose dopamine’ and diuretic therapy have been shown not to alter the course of AKI. The prognosis of AKI is highly dependent on the underlying etiology of the AKI. Children who have suffered AKI from any cause are at risk for late development of kidney disease several years after the initial insult. Therapeutic interventions in AKI have been largely disappointing, likely due to the complex nature of the pathophysiology of AKI, the fact that the serum creatinine concentration is an insensitive measure of kidney function, and because of co-morbid factors in treated patients. Improved understanding of the pathophysiology of AKI, early biomarkers of AKI, and better classification of AKI are needed for the development of successful therapeutic strategies for the treatment of AKI.     

脓毒症的急性肾损伤

脓毒症是危重病患者的常见病因或并发症，也是大家熟知的引起急性肾损伤（AKI）和多脏器功能障碍综合征（MODS）的常见危险因素。急性肾功能衰竭（ARF）发生率在一般脓毒症患者约为19％；在重度脓毒症约为23％；在血培养阳性的脓毒症休克者可高达51％。ARF并发脓毒症的病死率高达70％，明显高于无并发脓毒症的45％。因此，研究并了解AKI和脓毒症的相互关系和作用机制，将有助于降低脓毒症时AKI的高发病率以及相关的高器官衰竭率和病死率。     

Triage: In austere environments and echeloned medical systems

Although triage as a medical sorting process was originally developed and applied to echeloned military field medical systems dealing with mass casualties, the term has now permeated most aspects of medical practice. This essay attempts to refocus on triage in military and disaster settings, emphasizing the relationship of the echeloned system organization to the triage process, and the various non-medical factors which may influence triage decisions and priorities. Due to the lack of any analogous civilian experience, it is essential that all health personnel who may be involved in an echeloned care system gain and maintain proficiency by frequent involvement in appropriate training exercises, the characteristics of which are described.

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Resumen Aunque el triage, como proceso de selección médica, fue originalmente desarrollado y aplicado en sistemas militares escalafonados de campo que atendían heridos en masa, el término ha sido introducido en la mayoría de los aspectos de la práctica médica civil. Este artículo intenta reenfocar el triage en los escenarios militares y de desastre, haciendo énfasis en la relación entre la organización de los sistemas escalafonados y el proceso de triage, y los diversos factores no médicos que pueden influenciar las decisiones y prioridades del triage. Puesto que no existe una experiencia civil similar, es esencial que la totalidad del personal de salud que pueda verse involucrado en un sistema escalafonado de atención médica adquiera y mantenga experiencia mediante su frecuente participación en buenos programas de capacitación, cuyas características se describen.

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Résumé Bien que le terme triage ait été à l'origine destiné à définir et à s'appliquer aux procédés de sélection des blessés en cas de catastrophes collectives, ce terme s'applique aujourd'hui à pratiquement tous les aspects de la médecine. Cet essai a comme but de définir les grandes lignes du triage en milieu militaire ou en cas de grandes catastrophes, de souligner l'importance de l'hierarchie dans ce système ainsi que d'insister sur les facteurs non médicaux qui peuvent influencer les décisions et les priorités du triage. En raison de l'absence d'expérience analoque en pratique civile, il est essentiel que tout le personnel médical pouvant être intéressé par un système de soins échelonné, acquière et maintienne une connaisance en la matière par une participation active, fréquente des exercises d'entrainement. Les points essentiels de ceux-ci sont décrits ici.

     

Acute kidney injury in cancer patients

Clinical and Experimental Nephrology - We want to know the causes of AKI in oncology patients, including disease-related complications and the nephrotoxicity of chemotherapy drugs, in order to...     

Perioperative management of patients with chronic kidney disease or ESRD

The perioperative management of patients with chronic kidney disease (CKD) or dialysis-dependent end-stage renal disease (ESRD) is complicated by both the underlying renal dysfunction, with associated disturbances of fluid and electrolyte homeostasis and altered drug clearance, and the presence of associated co-morbid conditions, including diabetes mellitus, chronic hypertension and cardiovascular and cerebrovascular disease. The impact of CKD on fluid and electrolyte management, haematological and cardiovascular complications and drug management in the perioperative period are reviewed. Special issues related to the management of haemodialysis and peritoneal dialysis patients in the perioperative period are also reviewed.     

Acute kidney injury in scrub typhus

Background

We studied the urinary abnormalities and acute kidney injury (AKI) as per RIFLE criteria in scrub typhus.

Methods

A prospective case record-based study of scrub typhus was carried out from January 2009 to December 2010 in a tertiary hospital in South India. Patients were followed up until renal recovery or for at least 3 months after discharge. Univariate, chi-squared tests and multivariate logistic regression analyses were performed to identify the predictors of AKI.

Results

Scrub typhus was diagnosed in 259 patients. Urinary abnormalities were seen in 147 patients (56.7 %) with 60 patients (23.2 %) having AKI. All AKI patients had urinary abnormalities and 17 (28.3 %) were oliguric. Applying RIFLE (risk, injury, failure, loss, end-stage kidney disease) criteria, R, I, F were present in 23 (38.33 %), 13 (21.67 %), and 24 patients (40 %), respectively. Creatine phosphokinase (CPK) was raised in 33 patients (55 %) and hemodialysis was required in 6 patients (10 %). The case fatality rate in this study was 2 out of 259 (0.77 %), both having AKI and others recovering clinically. Significant predictors of AKI were tachycardia [odds ratio (OR) 2.28], breathlessness (OR 2.281), intensive care requirement (OR 2.43), mechanical ventilation (OR 3.33), thrombocytopenia (OR 2.90) and CPK >80 U/L (OR 1.76) by univariate analysis and intensive care requirement (adjusted OR 2.89) and thrombocytopenia (AOR 2.28) by multivariable logistic regression.

Conclusion

Scrub typhus should be part of the differential diagnosis of acute febrile illness with AKI. AKI in scrub typhus is usually mild, non-oliguric, and renal recovery occurs in most patients. Rhabdomyolysis may be contributory to AKI. Thrombocytopenia and intensive care requirement are significant predictors of AKI in scrub typhus.     

Acute kidney injury in surgical patients

Acute kidney injury (AKI) is a common and dangerous complication of surgical admission with even mild degrees of renal dysfunction being associated with reduced survival. Unfortunately, as confirmed by the UK's National Confidential Enquiry into Patient Outcome and Death (NCEPOD), its recognition is often delayed and management frequently sub-optimal. A failure to recognize relevant risk factors may expose surgical patients, unnecessarily, to an increased likelihood of developing AKI. In this review article, we present a structured approach to prevention, diagnosis and initial management that should provide a framework for the clinical care of all patients either at risk of, or suffering with, AKI.     

Acute kidney injury in older adults

Aging kidneys undergo structural and functional changes that decrease autoregulatory capacity and increase susceptibility to acute injury. Acute kidney injury associates with duration and location of hospitalization, mortality risk, progression to chronic kidney disease, and functional status in daily living. Definition and diagnosis of acute kidney injury are based on changes in creatinine, which is an inadequate marker and might identify patients when it is too late. The incidence of acute kidney injury is rising and increases with advancing age, yet clinical studies have been slow to address geriatric issues or the heterogeneity in etiologies, outcomes, or patient preferences among the elderly. Here we examine some of the current literature, identify knowledge gaps, and suggest potential research questions regarding acute kidney injury in older adults. Answering these questions will facilitate the integration of geriatric issues into future mechanistic and clinical studies that affect management and care of acute kidney injury.     

Acute kidney injury in the elderly population

The elderly population is more prone to acute kidney injury (AKI) than younger populations. Older patients have less renal reserve because of reduced glomerular filtration rates due to anatomic/functional changes, and concomitant diseases such as hypertension, diabetes, atherosclerosis, heart failure, ischemic renal disease, and obstructive uropathy. The risk of AKI may also increase as a result of aggressive diagnostic and therapeutic procedures, which include medical agents, radiology, and surgical intervention. AKI in the elderly has a multifactorial physiopathology due to different etiologies. Studies that have specifically compared prognosis of AKI in elderly versus young over the recent years suggest that age is a predictor of long-term outcome. In most cases, the treatment of AKI is similar for all age groups. The majority of critically ill patients with AKI will eventually need renal replacement therapy (RRT). The influence of RRT on renal outcome remains a subject of intense investigation and debate. Avoiding situations that could damage the kidney is an important strategy to prevent AKI development in the elderly, besides medical and interventional therapeutics.     

Acute kidney injury and the critically ill

Acute renal failure is commonly encountered in the intensive care unit. It is associated with considerable morbidity and mortality. There are many possible aetiologies in the critically ill, including nephrotoxic agents, hypovolaemia and sepsis. While many classification systems for acute renal failure exist, the RIFLE (Risk, Injury, Failure, Loss, End-stage) criteria and the Acute Kidney Injury Network (AKIN) criteria are the most commonly utilized. Many supportive therapies are employed to minimize the degree of renal injury once recognized, such as fluid resuscitation, maintenance of an adequate mean arterial pressure (with the use of vasopressors in persistent hypotension despite fluid and treatment of the underlying aetiology). However, if renal failure becomes established, then renal replacement therapy (RRT) may be needed to maintain homeostasis. While there are no clear guidelines with respect to the ideal mode or timing of RRT, we will discuss pros and cons of the various options.     

Acute kidney injury in hematopoietic cell transplantation

Hematopoietic cell transplantation is becoming an increasingly common treatment modality for a variety of diseases. However, patient survival may be limited by substantial treatment-related toxicities, including acute kidney injury (AKI). AKI can develop in approximately 70% of patients posttransplant and is associated with an increased risk of morbidity and mortality. The development of AKI varies depending on the type of conditioning regimen used and the donor cells infused at the time of transplant, and the etiology often is multifactorial. Epidemiology, risk factors for development, pathogenesis, and potential treatment options for AKI in the hematopoietic cell transplantation population are reviewed as well as newer data on early markers of renal injury. As the indications for and number of transplants performed each year increases, nephrologists and oncologists will have to work together to identify patients who are at risk for AKI to both prevent its development and initiate therapy early to improve outcomes.     

Acute kidney injury and the critically ill

Acute renal failure is commonly encountered in the intensive care unit. It is associated with considerable morbidity and mortality. There are many possible aetiologies in the critically ill, including nephrotoxic agents, hypovolaemia and sepsis. While many classification systems for acute renal failure exist, the RIFLE (Risk, Injury, Failure, Loss, End-stage) criteria and the Acute Kidney Injury Network (AKIN) criteria are the most commonly utilized. Many supportive therapies are employed to minimize the degree of renal injury once recognized, such as fluid resuscitation and maintenance of an adequate mean arterial pressure (with the use of inotropes in persistent hypotension despite fluid and treatment of the underlying aetiology). However, if renal failure becomes established, then renal replacement therapy (RRT) may be needed to maintain homoeostasis. While there are no clear guidelines with respect to the ideal mode or timing of RRT, we will discuss pros and cons of the various bedside options.     

Acute kidney injury and chronic kidney disease after cardiac surgery

Kidney dysfunction is common after cardiac surgery and predicts mortality risk and poorer long-term outcome, particularly when acute injury superimposes upon chronic kidney disease. Numerous insults contribute to perioperative renal impairment including major surgical trespass, procedure-specific interventions (eg, deep hypothermic circulatory arrest), and postoperative complications. Regardless of cause, evidence supports a role for renal impairment and accumulation of "uremic toxins" as direct contributors to adverse outcome. No one has yet characterized a loss of renal function small enough to be insignificant. Despite considerable research focus, progress in development of interventions aimed at perioperative renoprotection has been disappointing. However, practice modifications can influence the likelihood of acute kidney injury, and several recent advances provide hope for the future. We review pathophysiologic understanding of this disorder; evaluate the confusing relationship (causal v epiphenomena) among acute kidney injury, chronic kidney disease, and adverse outcome after cardiac surgery; and provide an evidence-based assessment of the conduct of cardiac surgery and renoprotection strategies.