Practice Of Critical Care Medicine Research Articles

Evolving Practices in Critical Care and Potential Implications for Management of Acute Kidney Injury

Acute kidney injury (AKI) is a common complication in hospitalized patients, with an incidence of 3 to 10% (1–4). In-hospital mortality rates that are associated with AKI remain high, in the range of 30 to 70% (5–8), despite significant improvements in dialytic technology as well as important advances in critical care, which have resulted in improved survival for other critical illnesses, including acute lung injury and sepsis (9). These improvements include continuous renal replacement therapies, which allow for continuous removal of solutes and fluid and may be tolerated better from a hemodynamic standpoint, and biocompatible dialysis membranes, which are associated with reduced complement and granulocyte activation. In general, indications for dialysis in the acute care setting have been extrapolated from those that are applied in chronic kidney disease, including volume overload that is refractory to diuretic therapy; electrolyte abnormalities (in particular hyperkalemia); uremic complications (pericarditis or pleuritis); severe acidosis (pH < 7.20); and selected toxic ingestions, such as methanol, ethylene glycol, and other water-soluble agents (10,11). However, the evidence base supporting specific dialysis practices in the acute care setting is limited. For example, several studies that were completed in the 1960s and 1970s compared “early” and “late” initiation of dialysis, using blood urea nitrogen (BUN) to define early and late (Table 1). These studies primarily were cohort studies that used historical controls, not randomized, clinical trials. The results of these investigations, along with extrapolation from the ESRD population, promoted recent practice patterns. Currently, many nephrologists often delay dialysis in the acute care setting until the patient has an impending complication of AKI, such as hyperkalemia leading to cardiac arrhythmias, acidosis resulting in hypotension, or oliguria leading to volume overload or hypoxemia, or until the BUN exceeds 100 mg/dl (18). Given differences in protein catabolism, …

Update in Critical Care 2005

Randomized controlled trials (RCTs) stopped earlier than planned because of apparent benefit, such as PROWESS (Recombinant Human Activated Protein C Worldwide Evaluation in Severe Sepsis) and the ARDS (Acute Respiratory Distress Syndrome) Network low tidal volume study, often generate considerable excitement and affect clinical practice. Montori and coworkers (1) systematically reviewed RCTs involving interventions stopped early for benefit, finding that such trials are becoming more common, often fail to adequately report relevant information about the stopping decision, and show implausibly large treatment effects, particularly when the number of events is small. Because the decision to stop is typically driven by highly significant p value thresholds, trials that are terminated early because of apparent benefit will frequently show large treatment effects, even when the number of events is large. In the future, journals should require adequate reporting about the stopping decision. Glance through any major medical journal and you will increasingly encounter terms from the world of molecular medicine that, unless you live in that world, are unfamiliar and sometimes meaningless. A supplement to Critical Care Medicine (2) attempts to demystify these terms with a series of short articles by international experts that use extensive illustrations and diagrams to emphasize the value of these concepts in the context of the “real world” practice of critical care medicine.

Obituary: William J Sibbald, MD, FRCP(C)

William Sibbald was born June 28, 1946, and died September 14, 2006, at his home in Toronto, Ontario, surrounded by his family after a two-year battle with cancer. He was 60 years old. Up until two days before his death, he remained the Physician-in-Chief of Sunnybrook Health Sciences Centre in Toronto, Editor-in-Chief of the Journal of Critical Care and a lifelong dynamic force for the advancement of critical care medicine regionally, nationally and around the world. His last days were given to his family. His primary love was his children, for whom he was a tireless supporter. He was a committed and compassionate physician, healthcare pioneer, renowned researcher, tireless leader, inspirational teacher, and generous mentor. For those of us who knew him personally, he was truly an impressive force for good in acute care medicine. He was also a highly valued member of the Editorial Board of this journal. Except for a fellowship in Critical Care Medicine at Wayne State University, Bill received all his medical school and internal medicine training in the University of Western Ontario in London, Ontario, where he subsequently helped create and run the Richard and Jean Ivey Critical Care and Trauma Unit of Victoria Hospital for 23 years from 1977 to 2000. Afterward he moved to Toronto to become the Physician-in-Chief at Sunnybrook Health Sciences Centre, supporting the largest collection of intensive care unit beds in Canada. Bill's academic career mirrored the man in that it was characterized by insightful and important observations, varied and evolving interests. His initial research focused on cardiovascular function as he worked to understand the physiology of sepsis and trauma. However, he rapidly branched into nearly every aspect of clinical research in the intensive care setting, including ethics issues in the intensive care unit setting, process control, technology transfer and the practical application of evidence-based medicine. Some of the more quantifiable products of these efforts were more than 260 peer-reviewed publications, 70 chapters and 9 monographs and textbooks. But these numbers cannot estimate the impact that Bill had on the practice of critical care medicine. He literally touched the lives of most of the academic leaders in critical care around the world, personally trained countless students and helped forge insightful and reasonable healthcare policy for his native province of Ontario as well as defining similar principles worldwide. In recognition of these efforts Dr Sibbald received the Dean's Award of Excellence, Faculty of Medicine, University of Western Ontario, in 1997, Distinguished Investigator Award, American College of Critical Care Medicine, in 1998, a fellowship at the Royal College of Physicians and Surgeons, Edinburgh, in 2002, and the Distinguished Service Award, Society of Critical Care Medicine, in 2004. We shall all miss the dynamic presence and positive energy that Bill brought to every occasion. But he will be remembered for the large body of work etched into the fabric of medicine through his studies, teaching and personal efforts that will make his positive imprint everlasting as memories fade and life goes on.

Paradigm of the injury-repair continuum during critical illness.

To define injury and repair in the context of critical illness. Review of the literature. The medical practice of critical care medicine has long been one of aggressive assistance and support: utilizing state of the art technology to support the functions of the human body until homeostasis is again achieved and the patient is functioning sufficiently to allow the support to discontinue. Injury is defined as the disruption of molecular, cellular, or organ functions resulting from an external or internal stimulus. Repair is defined as an adaptive process that occurs in response to injury and involves both local and systemic responses that serve to restore structure and regulation for the purpose of organ/tissue function. The study of injury in critical illness is now occurring "upstream," at the genetic and cellular levels, to understand how damaging effects of acute inflammation from injury can be prevented or modulated. To treat the patient with critical illness more effectively, it is important to understand both the cause of the insults and the repair processes triggered by the insults because both processes affect the eventual course of the critical illness.

Ethyl pyruvate: a novel anti-inflammatory agent.

Pyruvate plays a central role in intermediary metabolism. Pyruvate, however, is also a potent antioxidant and free radical scavenger, and numerous studies have shown that treatment with this compound can be salutary in numerous pathologic conditions that are thought to be mediated, at least in part, by redox-dependent phenomena. Unfortunately, aqueous solutions of pyruvate rapidly undergo an aldol-like condensation reaction to form 2-hydroxy-2-methyl-4-ketoglutarate (parapyruvate), a compound that is a potent inhibitor of a critical step in the mitochondrial tricarboxylic acid cycle. To circumvent this issue, our laboratory formulated a derivative of pyruvic acid, ethyl pyruvate, in a calcium- and potassium-containing balanced salt solution. We showed that treatment with this fluid could ameliorate much of the structural and functional damage to the intestinal mucosa caused by mesenteric ischemia and reperfusion in rats. In subsequent studies, we showed that treatment with ethyl pyruvate solution could improve survival in rodent models of hemorrhagic shock and resuscitation and also down-regulate a number of proinflammatory genes. Recently, ethyl pyruvate was also shown to improve survival in murine models of acute endotoxemia and bacterial peritonitis. Although the biochemical basis for the anti-inflammatory actions of pyruvate remain to be elucidated, this simple compound warrants further evaluation as a treatment for a number of conditions commonly encountered in the practice of critical care medicine.

Clinical information systems and the electronic medical record in the intensive care unit

The integration of computers into critical care is by no means a new concept. Clinical information systems have evolved in the critical care setting over the past three decades. Their use by critical care healthcare providers has increased exponentially in the past few years. More recently, with the advent of the electronic medical record, clinicians in the ICU may obtain and share useful information both bedside and remotely. Clinical information systems and the electronic medical record in the ICU have the potential to improve medical record movement problems, to improve quality and coherence of the patient care process, to automate guidelines and care pathways, and to assist in clinical care and research, outcome management, and process improvement. In this article, we provide some historical background on the clinical information system and the electronic medical record and describe their current utilization in the ICU and their role in the practice of critical care medicine in decades to come.

Current Issues Affecting Critical Care Practice

Internal and external forces continue to impact the practice of critical care medicine. Contracting for purchase of hospital services will soon be guided by the presence or absence of specific hospital attributes, including computerized physician order entry, evidence-based hospital referral, and the staffing model for intensive care unit care. The Leapfrog group, a consortium of health care purchasers, prefers to contract with hospitals that have implemented full-time intensive care unit physician staffing. This requirement is likely to increase the demand for critical care specialists. Personnel shortages are already apparent in critical care nursing and are expected to occur with physician specialists as well. Other current issues include the demand for increasingly detailed information on intensive care unit outcomes, a focus on patient safety, and cost control.

Clinical review: status epilepticus.

Status epilepticus (SE) has an annual incidence exceeding 100,000 cases in the United States alone, of which more than 20% result in death. Thus, increased awareness of presentation, etiologies, and treatment of SE is essential in the practice of critical care medicine. This review discusses current definitions of SE, as well as its clinical presentation and classification. The recent literature on epidemiology is reviewed, including morbidity and mortality data. An overview of the systemic pathophysiologic effects of SE is presented. Finally, significant studies on the treatment of acute SE and refractory SE are reviewed, including the use of anticonvulsants, such as benzodiazepines, and other drugs.

Information technology in the practice of critical care medicine

Information technology in the practice of critical care medicine

Introduction

The last 20 years have seen major changes in the practice of critical care medicine. Initially sustained by emerging mechanical ventilation technology and the part-time dedication of interested anesthesiologists, it has gone on to become an established feature of all tertiary institutions, with dedicated and trained specialists, an expanding specific knowledge base, and ongoing research unique to its needs. Critical care medicine is now a well-established medical specialty with specific therapies, publications, practical and cognitive skills, and procedures. The development of intensive care units in particular has had major implications for the kind of surgery that can be performed routinely (such as coronary artery by-pass surgery) and for the type of patients (older and with significant chronic diseases) who can be successfully treated. The evolution of critical care medicine has also had significant implications for clinical nephrologists. One major development has to do with the nature, epidemiology, and management of severe acute renal failure (ARF). Severe ARF is now profoundly different in its epidemiology and associations from the disease seen by nephrologists 30 years ago. It is now seen predominantly in intensive care units, is usually associated with the dysfunction of other organs, and is often accompanied by sepsis. It is typically multifactorial, and has a very high mortality rate. The management of this type of ARF demands the application of complex knowledge and skills. Such knowledge and skills can come either from only a multidisciplinary approach in which nephrologist and intensivist work side by side to achieve optimal care for a given patient, or only from specialists originally from either field who have gone on to formally acquire training and expertise in both specialties. The time has come for the formal development of a specialty area called “Critical Care Nephrology.” The foundation for such an integrated approach has been hemofiltration therapy. Although originally developed to treat patients with end-stage renal disease, hemofiltration has rapidly grown as an important treatment for acute patients. From the original description of Peter Kramer in 1977 as a possible alternative to established techniques, today hemofiltration is a first choice technique for several clinical conditions, particularly multiple organ failure. The success of this technique, however, relies on a strong collaboration between the nephrologist and the intensive care specialist. There are important clinical reasons for collaborative care. Patients with renal failure are significantly more complex than 30 years ago. They almost always are elderly, have significant comorbidity, and have dysfunction of multiple organs. Renal failure cannot be viewed as a simple problem that will get better over time once the initial insult is gone and sufficient renal replacement therapy has been provided. Insights into such renal replacement therapy now reveal that the therapy itself may make a great deal of difference in the course of the disease. The use of continuous renal replacement therapy (CRRT) has partly redefined the indications for initiating dialytic therapy in the intensive care unit. It has expanded the possible role of blood purification in the management of critically ill patients, and it has widened the scope of interaction between the expertise of the nephrologist, the needs of the intensive care specialist, and their common goals for patient recovery. Critically ill patients keep dying at unacceptably high rates. Surely the answer to such a high mortality rate must be that physicians need to combine knowledge and expertise, be modest and collegial, and be constructive, nonconflictual, and interdisciplinary in their approach to patient care. In this issue of Kidney International, we collected the contributions presented as review and original articles at the Fourth International Congress on Hemofiltration held in Darmstadt, Germany on May 14th and 15th, 1999. The aim of this issue is to provide the scientific community with some of the latest contributions in the field of hemofiltration and multiple organ failure, providing a balanced mix between established knowledge and the newer results from clinical trials and basic research. We were able to assemble a group of outstanding scientists and clinicians who are actively involved in the treatment of critically ill patients with multiple organ failure. We hope this Supplement issue will serve as a tool for consultation and informative reading not only for experts, but also for the beginners of this field. We are grateful to our major sponsor, Hospal (Lyon, France), for supporting this meeting. We also appreciate the following sponsors: Baxter (McGaw Park, Illinois, USA), Braun (Melsungen, Germany), Fresenius Medical Care (Bad Homburg, Germany), Hoechst Marion Roussel (Bad Soden, Germany), Janssen-Cilag (Neuss, Germany), Ray-Med (Wiesbaden, Germany), and A. Schulz Lauterbach (Iserlohn, Germany).

Critical care ethics in Hong Kong: cross-cultural conflicts as east meets west.

The practice of critical care medicine has long been a difficult task for most critical care physicians in the densely populated city of Hong Kong, where we face limited resources and a limited number of intensive care beds. Our triage decisions are largely based on the potential of functional reversibility of the patients. Provision of graded care beds may help to relieve some of the demands on the intensive care beds. Decisions to forego futile medical treatment are frequently physician-guided family-based decisions, which is quite contrary to the Western focus on patient autonomy. However, as people acquire knowledge about health care and they become more aware of individual rights, our critical care doctors will be able to narrow the gaps between the different concepts of medical ethics among our professionals as well as in our society. An open and caring attitude from our intensivists will be important in minimizing the cross-cultural conflict on the complex issue of medical futility.

FAST TRACK: What Is It?

Over the past few years, a large number of centers have converted to a strategy of early extubation in patients undergoing cardiothoracic surgery. Selected patients are targeted for extubation on the day of surgery, usually within 4 hours of the completion of cardiac revascularization. The approach was first fueled by the economic realities of the 1990s, in which there has been pressure to shorten patient time in the intensive care unit (ICU) and length of hospital stay (LOS). Leading the push for decreased LOS has been reduced reimbursement from third-party payers. In some ways, that is reminiscent of the past 20 years, during which outpatient surgery and anesthesia became increasingly popular. But we as physicians also have a more important bottom line—patient safety and outcome. Physicians have an obligation to ask whether such cost containment through earlier extubation carries additional risks. Previous guidelines of heavy premedication and high-dose narcotics with overnight mechanical ventilation had been shown to reduce perioperative ischemia.4 That technique is inconsistent with early extubation. Definitive outcome studies are only now beginning to be presented. The data so far suggest that early extubation is not associated with any increased risk of mortality or morbidity, including, specifically, myocardial ischemia or infarction.3 Our group has found no decrement in quality indicator responses since starting a program of fast tracking. Overall, the use of fast tracking has greatly increased the turnaround time and efficacy of the ICU service. But how do anesthesiologists not currently involved in cardiac anesthesia or the practice of critical care medicine relate to this new strategy of rapid recovery? The anesthesiologist, with his or her unique training in perioperative physiology and expertise in pharmacology, is an ideal health care professional to take the lead in program development for fast-track medicine. The anesthesiologist should manage both the medical and administrative duties related to safe, rapid patient flow. Patient flow is a better concept than “early extubation.” “Early extubation” downplays the real role of the anesthesiologist and trivializes the real role of fast tracking, which is to provide high-quality medical care in a safe and cost-effective manner. The anesthesiologist should manage the medical integration of the patient flow system throughout its evolution—staff education; meticulous intraoperative anesthetic care; and postoperative pharmacologic control of hemodynamic, respiratory, and renal function. The patient flow system should be followed through to its logical conclusion— improved patient outcome. To truly introduce such a program, team development must be at the centerpoint of the program. A multidisciplinary team in which each member brings to the table his or her expertise and has a vested interest in program success will guarantee excellence. Team membership should include surgeons, critical care nurses, administrators, and pharmacologists. Each of those individuals has governance over specific aspects of how the patient moves along the track of good patient care to patient satisfaction. We must design systems that allow ongoing self-evaluation and growth. The onset programs in fast tracking must have quality assurance programs integrated within them. Ongoing internal review should include both traditional outcome indicators such as LOS and complications, and include staff acceptance indicators and an evaluation of costs. One of the quality indicators we found highly important in this consumer-driven society was patient-focused satisfaction surveys. It is very satisfying for staff to see the level of patient acceptance when a new program is introduced. The opportunities for anesthesiologists are unlimited in this ongoing quality assurance program; administration and medical peers quickly realize the true scope of practice of our specialty in disease and patient management.

INTUBATION OF CRITICALLY ILL PATIENTS

Airway management of critically ill patients has been enhanced by the recent introduction of several new types of artificial airways and laryngoscopes. New drugs for sedation and neuromuscular blockade have been developed to facilitate care of the intubated patient. Guidelines for management of the difficult airway have been introduced. Several new prospective studies have improved our understanding of complications of intubation and how to avoid these sometimes tragic events. A consensus is evolving that TLI and tracheotomy each have clear advantages and disadvantages in prolonged airway maintenance and that multiple factors, not simply the duration of TLI, must be considered in the optimal timing of tracheotomy for each patient. Complex medicolegal and ethical issues directly impact intubation, perhaps more so than any other practice in critical care medicine. Physicians who care for critically ill patients should be familiar with these recent developments and concepts in airway management.

Measurement of blood CO2 concentration with a conventional PCO2 analyzer.

CO2 content can be determined from the Pco2 in an acidified (forces all CO2 into solution) and diluted blood sample. However, Pco2 concentrations measured in conventional blood gas analyzers are only correct for samples with a significant buffer capacity (such as whole blood), so that mixing with the Pco2 in the rinse solution and tubing walls does not significantly change the sample Pco2. This study describes a calibration method and validation data for the Radiometer Medical ABL2 CO2 electrode system to accurately measure unbuffered blood samples used in the determination of blood CO2 content (or other aqueous fluids). Prospective, criterion standard. Laboratory. Blood samples (0.4 mL) were acidified and diluted with 0.2 M lactic acid. After measuring Pco2, CO2 content was calculated using the CO2 solubility coefficient and the dilution factor of 20. CO2 content was determined in a series of sodium carbonate (Na2CO3) solutions spanning the physiologic range of CO2 content. Regression of the measured vs. the actual CO2 content data generated a straight line with a slope of 0.796 and y-intercept of 12.5 (r2 = .99; n = 48). These coefficients were successfully used to correct CO2 content determined in blood samples into which graduated amounts of sodium carbonate were added. This calibration procedure allows accurate measurement of Pco2 in aqueous samples using the Radiometer ABL2 electrode system, and should be applicable to other blood gas analyzers. Necessary syringes and chemicals are readily available, the method is fast and simple, and the sample volume is small. In the practice of critical care medicine, accurate Pco2 measurement in aqueous acidified and diluted blood provides direct determination of blood CO2 content (useful in calculations of modified Fick cardiac output or tissue CO2 production). Determinations of absolute CO2 content in blood requiring complex methodology are not necessary. In addition, accurate measurement of aqueous gastric Pco2 can help determine gastric pH, which is an important marker of tissue perfusion.

Textbook of Critical Care

There has been an explosion in both basic research and clinical experience that has led to rapid expansion of the knowledge base required for the practice of critical care medicine. The editors of the third edition of Textbook of Critical Care have attempted to provide a comprehensive and standard textbook designed to supply extensive breadth and depth of information for the health care provider at the bedside in the intensive care unit (ICU). Like the discipline of critical care medicine itself, this textbook offers a multidisciplinary approach to the care of the critically ill patient. It has more than 330 contributors who are leaders in the development of this newest of medical disciplines. The editors and contributors clearly have accomplished their goal. The text is divided into sections, each focused on a single organ system or organizational element of the critical care unit. An introductory section contains an excellent chapter

Errors and Bias in Using Predictive Scoring Systems

Scoring systems used to predict clinical outcomes for critically ill patients have been refined in the past decade, yet even the most recently developed systems contain flaws that limit their application. In general, prediction rules are derived by defining an association between a number of clinical variables and a particular outcome in a reference patient population. By systematically examining the qualities of the independent variables and the size and scope of the derivation data set, potential sources of error and bias can be identified. Existing and future predictive systems must be validated on large groups of patients and continuously updated to keep pace with new approaches to the practice of critical care medicine.

Attitudes of anesthesiology residents toward critical care medicine training.

The number of anesthesiology residents pursuing critical care medicine (CCM) fellowship training has been decreasing in recent years. A significant number of training positions remain unfilled each year. Possible causes of this decline were evaluated by surveying residents regarding their attitudes toward practice and training in CCM. All 38 anesthesiology programs having accredited CCM fellowships were surveyed. Four of these and one program without CCM fellowships were used to develop the survey instrument. Four programs without CCM fellowships and 34 programs with CCM fellowships make up the survey group. Returned were 640 surveys from 37 (97%) programs accounting for over 30% of the possible residents. Resident interest in pursuing CCM training decreased as year of residency increased (P < 0.0001). Residents in programs with little patient care responsibility during intensive care unit (ICU) rotations expressed less interest in CCM training (P < 0.012). The administrative role of the anesthesiology department in the ICU also influenced resident interest (P < 0.014). Written responses to open-ended questions suggested resident concerns with the following: stress of chronic care, financial consequences of additional year of training, ICU call frequency and load, ICU role ambiguity, and shared decision-making in the ICU. A recurring question was, "Are there jobs (outside of academics) for anesthesiologist intensivists?" Most residents knew a CCM anesthesiologist they admired and knew that there were unfilled fellowship positions available. Defining the job market, improving curriculum and teaching, supporting deferment of student loans, and introducing residents and medical students to the ICU earlier may increase the interest in CCM practice among anesthesiology residents.

Adoptive immunotherapy of gram-negative sepsis: use of monoclonal antibodies to lipopolysaccharide.

To provide a succinct overview of the scientific rationale for adoptive immunotherapy of Gram-negative sepsis using antibodies directed at epitopes in the core region of the lipopolysaccharide molecule. Relevant, English-language primary and secondary (i.e., review) articles dealing with the structure or toxicity of lipopolysaccharide or adoptive anti-endotoxin immunotherapy in animals or man. The review emphasizes the findings obtained in several recent multicenter, randomized, prospective trials of monoclonal antibodies to core determinants of lipopolysaccharide. Lipopolysaccharide, a component of the outer cell wall of Gram-negative bacteria, is a complex molecule consisting of three regions: lipid A, core polysaccharide, and O-antigenic side chains. Epitopes in the lipid A and core polysaccharide regions are highly conserved across species and strains of Gram-negative bacteria. Because of the availability of mutant strains of bacteria that synthesize lipopolysaccharides lacking O-specific side chains and, in some instances, portions of the core polysaccharide moiety, investigators have been able to develop polyclonal and monoclonal antibodies to core-region determinants. In experimental animals, many of these antibodies have been shown to protect against the deleterious effects of either purified heterologous lipopolysaccharides or viable heterologous Gram-negative bacteria. Recently, two different monoclonal "anti-core" antibodies (HA-1A and E5) were evaluated in prospective, placebo-controlled, double-blind, randomized trials. In the pivotal trial of HA-1A, a human monoclonal IgM, no treatment effect was discernible when data from all patients enrolled in the study were analyzed. However, in a subset of patients with positive blood cultures for Gram-negative organisms, there was a decrease in all-cause mortality over a 28-day observation period in patients treated with HA-1A, as compared with those patients treated with placebo (p = .014). Interpretation of this finding, however, is confounded because multiple other subsets and end-points also were analyzed, necessitating an adjustment in the p value necessary to reject the null hypothesis. A murine monoclonal IgM called E5 was evaluated in two separate trials. In the first trial, improved survival over a 30-day observation period was observed in a subset of patients with Gram-negative sepsis without refractory shock (p = .01). However, in a second trial of E5, which focused on this subset, a statistically significant improvement in survival was not observed in patients with documented Gram-negative sepsis without shock. Adoptive immunotherapy using monoclonal anticore antibodies seems to improve survival rate in selected patients with Gram-negative sepsis. Nevertheless, because of concerns about costs and the interpretation of the results from the completed clinical trials, these new agents have generated enormous controversy. The precise role of adoptive immunotherapy against lipopolysaccharide in the practice of critical care medicine in the United States remains unclear.

Hypocalcemia in critically ill patients

To review calcium regulation, causes of hypocalcemia during critical illness, clinical features and treatment of hypocalcemia, hemodynamic effects of calcium administration, calcium-catecholamine interactions, and the role of calcium in ischemic injury. Representative articles from the medical literature are used to support the discussion of selected aspects of calcium metabolism which are important to the practice of critical care medicine. Results from both animal and human investigations and both in vitro and in vivo studies are discussed. Circulating calcium levels are best measured using ionized calcium electrodes. Ionized hypocalcemia is common in critically ill patients and usually results from impaired parathyroid hormone secretion or action, impaired vitamin D synthesis or action, or calcium chelation/precipitation. Ionized hypocalcemia most commonly presents as cardiovascular or neuromuscular insufficiency. Mild ionized hypocalcemia (greater than 0.8 mmol/L) is usually asymptomatic and frequently does not require treatment. Moderate-to-severe ionized hypocalcemia is best treated with iv calcium in the critically ill patient. The majority of studies report no increase in cardiac output but a significant increase in BP after iv calcium administration. When administered with beta-adrenergic agonists, calcium frequently impairs their cardiovascular actions. Intracellular calcium dysregulation is common during ischemic and shock states. Agents which increase intracellular calcium may be harmful during cellular ischemia. Alterations in calcium regulation and calcium concentrations are common during critical illness. Optimal management of altered calcium concentrations requires an understanding of the pathophysiology behind these alterations.

When an indigent patient needs a helicopter: A case report and an accepted institutional policy

Emergency aeromedical systems have become an integral part of the practice of critical care medicine. These systems provide specialized care to the severely injured, including transport to the nearest trauma center with the highest level. Aeromedical physicians and nurses called to care for injured indigent patients, however, may be placed at odds with the financial interests of their institution. “Patient dumping” in aeromedicine may lead to ethical, legal, professional, and regulatory dilemmas for emergency professionals and health care institutions. Institutional policy for aeromedical transport of severely injured patients must be instituted, regardless of their ability to pay.