[Bird flu: what the intensivist must know]

In the last century, humankind has faced 3 major pandemics of influenza virus infections. The first one occurred in 1918 and caused a significant amount of deaths. It was also capable of crossing over species barrier and affecting mammals, and most worrisome, humans. Since then several outbreaks have been reported in the Southeast of Asia. Many patients with the flu-like illness have a severe course and the patient develops pneumonia and in some cases multiorgan failure involving liver, kidneys, brain and lungs. Since the virus lacks regulatory control of genetic division it undergoes constant mutations leading to new subtypes and, sometimes, new strains. The only drugs that have shown some protection are oseltamivir and zanamivir. It is crucial to develop effective and non-expensive vaccines to prevent the virus spread and infection not only in humans but in birds too.

Cardiopulmonary resuscitation directives on admission to intensive-care unit: an international observational study

BACKGROUND

Resuscitation directives should be a sign of patient's preference. Our objective was to ascertain prevalence, predictors, and procurement pattern of cardiopulmonary resuscitation directives within 24 h of admission to the intensive-care unit (ICU).

METHODS

We enrolled 2916 patients aged 18 years and older from 15 ICUs in four countries, and recorded whether, when, and by whom their cardiopulmonary resuscitation directives were established. By polychotomous logistic regression we identified factors associated with a resuscitate or do-not-resuscitate directive.

FINDINGS

Of 2916 patients, 318 (11%; 95% CI 9.8-12.1) had an explicit resuscitation directive. In 159 (50%; 44.4-55.6) patients, the directive was do-not-resuscitate. Directives were established by residents for 145 (46%; 40.0-51.3) patients. Age strongly predicted do-not-resuscitate directives: for 50-64, 65-74, and 75 years and older, odds ratios were 3.4 (95% CI 1.6-7.3), 4.4 (2.2-9.2), and 8.8 (4.4-17.8), respectively. APACHE II scores greater than 20 predicted resuscitate and do-not-resuscitate directives in a similar way. An explicit directive was likely for patients admitted at night (odds ratio 1.4 [1.0-1.9] and 1.6 [1.2-2.3] for resuscitate and do-not-resuscitate, respectively) and during weekends (1.9 [1.3-2.7] and 2.2 [1.5-3.2], respectively). Inability to make a decision raised the likelihood of a do-not-resuscitate (3.7 [2.6-5.4]) than a resuscitate (1.7 [1.2-2.3]) directive (p=0.0005). Within Canada and the USA, cities differed strikingly, as did centres within cities.

INTERPRETATION

Cardiopulmonary resuscitation directives established within 24 h of admission to ICU are uncommon. As well as clinical factors, timing and location of admission might determine rate and nature of resuscitation directives.

Management of the obese critically ill patient

The management of the morbidly obese critically ill patient is a challenging and formidable task. A better understanding of the pathophysiologic changes that occur with obesity and the complications unique to this group of patients may improve their outcome.

Critical care transport

The transport environment presents challenges not faced in the hospital arena. Both ground and air ambulance transport vehicles are hampered by space limitations, lack of universally available power, and physical forces of no importance in the stationary hospital environment. EMS personnel are typically used in ground and air transports augmented by hospital practitioners on request. The capabilities of EMS workers is limited, and their limits must be considered when any patient transport is conducted. Prior planning and understanding the limitations of the transport arena are the keys to successful transport. The future will likely see improvements in technology and integration of hospital delivery systems and patient management systems, expanding our ability to provide critical care outside the traditional ICU environment.

The diagnosis and management of hypertensive crises

Severe hypertension is a common clinical problem in the United States, encountered in various clinical settings. Although various terms have been applied to severe hypertension, such as hypertensive crises, emergencies, or urgencies, they are all characterized by acute elevations in BP that may be associated with end-organ damage (hypertensive crisis). The immediate reduction of BP is only required in patients with acute end-organ damage. Hypertension associated with cerebral infarction or intracerebral hemorrhage only rarely requires treatment. While nitroprusside is commonly used to treat severe hypertension, it is an extremely toxic drug that should only be used in rare circumstances. Furthermore, the short-acting calcium channel blocker nifedipine is associated with significant morbidity and should be avoided. Today, a wide range of pharmacologic alternatives are available to the practitioner to control severe hypertension. This article reviews some of the current concepts and common misconceptions in the management of patients with acutely elevated BP.

Hyponatremia, cerebral edema, and noncardiogenic pulmonary edema in marathon runners

BACKGROUND

Noncardiogenic pulmonary edema is often associated with increased intracranial pressure and can be the initial manifestation of hyponatremic encephalopathy. Marathon runners tend to develop conditions that lead to hyponatremia.

OBJECTIVE

To describe the development and treatment of noncardiogenic pulmonary edema in marathon runners that was associated with hyponatremic encephalopathy.

DESIGN

Case series.

SETTING

One university hospital and two community hospitals.

PATIENTS

Seven healthy marathon runners who had a history of nonsteroidal anti-inflammatory drug use. The runners collapsed after competing in a marathon and were hospitalized with pulmonary edema.

MEASUREMENTS

Plasma sodium levels, chest radiograph, electrocardiogram, cardiac enzyme levels, and magnetic resonance imaging or computed tomographic scans of the brain.

RESULTS

Patients had nausea, emesis, and obtundation. The mean (+/-SD) plasma sodium level was 121 +/- 3 mmol/L, and oxygen saturation was less than 70%. Electrocardiograms and echocardiograms were normal. Chest radiographs showed pulmonary edema with a normal heart. Creatine phosphokinase-MB bands, troponin levels, and pulmonary wedge pressure were not elevated. Scanning of the brain showed cerebral edema. All patients were intubated and mechanically ventilated. Treatment with intravenous NaCl, 514 mmol/L, increased plasma sodium levels by 10 mmol/L in 12 hours. Pulmonary and cerebral edema resolved as the sodium level increased. One patient had unsuspected hyponatremic encephalopathy and died of cardiopulmonary arrest caused by brainstem herniation. All six treated patients recovered and were well after 1 year of follow-up.

CONCLUSIONS

In healthy marathon runners, noncardiogenic pulmonary edema can be associated with hyponatremic encephalopathy. The condition may be fatal if undiagnosed and can be successfully treated with hypertonic NaCl.

Physicians' own preferences to the limitation and withdrawal of life-sustaining therapy

While limiting and forgoing therapy at the end of life is now accepted on medical, ethical, moral and legal grounds, many Americans continue to die with heroic measures being taken to prevent their death. Recent studies have demonstrated that physicians frequently attend to their patients without knowledge of their preferences with regards to end-of-life issues. It is postulated that a physician's personal preferences with regard to the limitation and withdrawal of life support and active euthanasia would effect the discussion they had with their patients. The purpose of this study was to analyze end-of-life preferences of a diverse group of practicing physicians. The participants were active attending physicians at a community hospital, a rural referral center, a large tertiary care referral academic complex, and a specialized tertiary care referral center all within the United States. A questionnaire was developed which was mailed to attending physicians at the four participating medical centers. The respondents provided basic demographic data, do-not-resuscitate (DNR) preferences under various clinical circumstances as well as responses to a number of case vignettes. Six hundred and forty physicians responded to the survey. The mean age of the respondents was 46 years; 72% were male. In the event of a cardiac arrest less than 20% of respondents would want to undergo cardiopulmonary resuscitation in the setting of chronic end stage organ failure; the positive response rate was 5% for metastatic cancer and 2% for Alzheimer's disease. If death was imminent, 87% of physicians indicated they would want treatment withdrawn. Similarly, 95% of respondents indicated that they would want treatment withdrawn should they be in a persistent vegetative state. Only 1% of respondents believed that health care providers should never remove or withhold life-sustaining therapy. Should they have advanced motor neuron disease, 38% of physicians indicated they would request that their life be ended. The majority of physicians surveyed volunteered that they would want life-sustaining measures to be limited at the end of their life. A significant number were in favor of active euthanasia. This study suggests that it is unlikely that physicians' personal beliefs in regards to end-of-life care result in the failure to discuss these issues with their patients.

The effect of acidified enteral feeds on gastric colonization in critically ill patients: results of a multicenter randomized trial. Canadian Critical Care Trials Group

OBJECTIVE

To evaluate the effect of acidified enteral feeds on gastric colonization in critically ill patients compared with a standard feeding formula.

DESIGN

Randomized, double-blind, multicenter trial.

SETTING

Eight mixed intensive care units at tertiary care hospitals.

PATIENTS

We recruited mechanically ventilated critically ill patients expected to remain ventilated for >48 hrs. We excluded patients with gastrointestinal bleeding, acidemia, and renal failure requiring dialysis. We enrolled 120 patients; 38% were female, age (mean +/- SD) was 57.6+/-19.3 yrs, and Acute Physiology and Chronic Health Evaluation II score (mean +/- SD) was 21.6+/-7.6.

INTERVENTIONS

Vital High Nitrogen (Abbott Laboratories, Ross Products Division, Columbus, OH) was used as the standard feeding formula for the control group (pH = 6.5). Hydrochloric acid was added to Vital High Nitrogen to achieve a pH of 3.5 in the experimental group.

MEASUREMENTS AND MAIN RESULTS

The main outcome measure was gastric colonization. Secondary outcomes included gastric pH, pneumonia, and mortality. The mean gastric pH in patients receiving acid feeds was lower (pH = 3.3) compared with controls (pH = 4.6; p<.05). One patient (2%) on acid feeds was colonized in the stomach with pathogenic bacteria, compared with 20 patients (43%) in the control group (p<.001). There was no difference in the incidence of pneumonia (6.1% in the acid feeds group vs. 15% in the control group; p = .19). Overall, there were 15 deaths in the acid feeds group and seven in the control group (p = .10); four patients in the acid feeds group and three in the control group died during the study period (p not significant).

CONCLUSIONS

Acidified enteral feeds preserve gastric acidity and substantially reduce gastric colonization in critically ill patients. Larger studies are needed to examine its effect on ventilator-associated pneumonia and mortality.

Automatic external defibrillators: lessons from the past, present and future

Coronary artery disease remains the leading cause of death in the United States and most developed countries. Many of the victims die from sudden cardiac arrests, resulting from dysrhythmias-most commonly ventricular fibrillation. Since most cardiac arrests occur outside the hospital, implementing emergency services in the field will have a great impact on survival. With the development of the modern automatic external defibrillator (AED), early recognition and correction of these dysrhythmias by lay rescuers can significantly improve outcome from sudden death. This paper reviews the past, present and future development and applications of AEDs.

Critical care and the World Wide Web

The Internet was created in 1969, when the Advanced Research Projects Agency of the United States Department of Defense fired up an experimental network consisting of only four computers. Over the past five years there has been an exponential explosion in the number of computers added to this network. It is estimated that Internet traffic doubles every 100 days with more than 100 million people worldwide now on-line. The Internet is so vast that practically every aspect of human interest is represented is some form or fashion. From recreation to applied science and technology, and from Critical Care Medicine case scenarios to digitized radiology images and pathology specimens, the Internet has become increasingly useful for critical care practitioners. To date, no resource is better equipped to assist critical care providers in many of their daily tasks. This article presents some of the historical developments of the Internet as well as common applications that are useful for critical care practitioners.

Management of increased intracranial pressure: a review for clinicians

Emergency physicians are frequently confronted with head-injured patients, many of whom have intracranial hypertension. Since direct correlations have been reported between increased intracranial pressure (ICP) and adverse outcome, it is important to rapidly identify and treat these patients. Furthermore, since the actual brain damage that occurs at the time of injury cannot be modified, the maximization of neurological recovery depends upon minimizing secondary insults to the brain, most notably preventing hypotension and hypoxemia. Volume resuscitation to maintain an adequate mean arterial pressure, airway control, and sedation and analgesia to prevent surges in ICP remain the cornerstone of early management. These principles and the emergency department management of the head-injured patient are reviewed in this paper.

Severity scoring and outcome assessment. Computerized predictive models and scoring systems

Severity of illness scoring systems and standardized death ratios are being used with increasing frequency as markers of quality of care and to compare and contrast the performance of ICUs. However, numerous factors unrelated to the quality of care delivered may impact the severity of illness score and standardized death ratios. This article reviews the commonly used severity scoring systems and factors that affect their predictive performance.

The ex vivo antimicrobial activity and colonization rate of two antimicrobial-bonded central venous catheters

OBJECTIVE

Catheter-related sepsis is an important complication associated with the use of central venous catheters. Recent studies have suggested that antimicrobial-bonded catheters may reduce catheter colonization and catheter-related sepsis. The aim of this study was to determine the relationship between the antimicrobial activity and the colonization rate of two commercially available antimicrobial-bonded central venous catheters.

DESIGN

Prospective, randomized, controlled, nonblinded study.

SETTING

Medical intensive care unit of a university-affiliated teaching hospital.

PATIENTS

One hundred twenty consecutive medical intensive care unit patients requiring new central venous catheters (fresh stick).

INTERVENTIONS

Patients were randomized to receive a) a Standard Arrow; b) an ARROWgard; or c) a Cook Bio-Guard Spectrum central venous catheter. Central venous catheters were removed when they were no longer required or when catheter-related sepsis was suspected. Under aseptic conditions, the distal 12 cm of the removed catheters were cut into six 2-cm segments. Semiquantitative culture was performed (by roll technique) on the distal segment. Colonization was defined as >15 colony-forming units. Using a modified Kirby-Bauer technique, the zone of inhibition of the remaining five segments was determined against the following organisms: methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Enterococcus faecalis, Acinetobacter baumannii, and Candida albicans Catheters that were removed within 24 hrs of insertion were excluded from the analysis.

MEASUREMENTS AND MAIN RESULTS

Seven patients were not assessable. The baseline clinical and demographic characteristics were similar among the three groups of patients. Eleven Standard Arrow (28%), seven ARROWgard (19%), and four Bio-Guard (11%) catheters were colonized (p = .05 for Bio-Guard vs. control). Staphylococci were the most common colonizing organisms. Two patients with Standard Arrow catheters (5%) and one patient with an ARROWgard catheter (3%) developed catheter-related sepsis. Antibiotic-coated catheters significantly inhibited the growth of all test organisms except C. albicans (p < or = .05). Zones of inhibition were significantly larger for the Bio-Guard compared with the ARROWgard catheter when tested against MRSA, S. epidermidis, and E. faecalis (p < or = .002).

CONCLUSION

The Bio-Guard central venous catheter had greater ex vivo antimicrobial activity against MRSA, S. epidermidis, and E. faecalis compared with the ARROWgard catheter, and this was associated with a significantly lower rate of catheter colonization.

Carbon monoxide poisoning: a review for clinicians

Carbon monoxide (CO) poisoning continues to be a significant health problem both in the United States and in many other countries. CO poisoning is associated with a high incidence of severe morbidity and mortality. Epidemics of CO poisoning commonly occur during winter months and sources include: smoke from fires, fumes from heating systems burning fuels, and exhaust fumes from motor vehicles. The history of exposure and carboxyhemoglobin levels should alert the physician to this diagnosis. In the absence of exposure history, CO poisoning should be considered when two or more patients are simultaneously sick. The clinical presentation is non-specific and may range from nausea and headache to profound central nervous system dysfunction. The mainstay of therapy for CO poisoning is supplemental oxygen, ventilatory support, and monitoring for cardiac dysrhythmias. This article reviews up-to-date information of this potentially devastating exposure.

The hemodynamic derangements in sepsis: implications for treatment strategies

The incidence of the sepsis syndrome has increased dramatically in the last few decades. During this time, we have gained new insights into the pathophysiologic mechanisms leading to organ dysfunction in this syndrome. Yet, despite this increased knowledge and the use of novel therapeutic approaches, the mortality associated with the sepsis syndrome has remained between 30% and 40%. Appropriate antibiotic selection and hemodynamic support remain the cornerstone of treatment of patients with sepsis. Recent studies have failed to demonstrate a global oxygen debt in patients with sepsis. Furthermore, therapy aimed at increasing systemic oxygen delivery has failed to consistently improve patient outcome. The primary aim of the initial phase of resuscitation is to restore an adequate tissue perfusion pressure. Aggressive volume resuscitation is considered the best initial therapy for the cardiovascular instability of sepsis. Vasoactive agents are required in patients who remain hemodynamically unstable or have evidence of tissue hypoxia after adequate volume resuscitation.