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This article discusses the therapeutic and toxic effects of sedative drugs and neuromuscular blocking agents in the critically ill patient. Common misconceptions of drug properties are highlighted and dispelled. A rational plan for the use of each type of drag is described. The appropriate use of sedative drugs may cause withdrawal syndromes; treatment options are outlined.

Pulmonary artery catheters are frequently used and may be the cause of pulmonary artery rupture. The “feel” of balloon inflation, a clinical sign of a “wedged” catheter, was noted to vary among different manufacturers' catheters. The inflation pressures of five catheters from four manufacturers were examined in the laboratory. Peak pressures ranged from 475 ± 10 mm Hg to 1,037 ± 36.8 mm Hg. Plateau pressures ranged from 220 ± 4 mm Hg to 495 ± 2.9 mm Hg. Catheters with high inflation pressures may make detection of a wedged catheter by feel impossible and, thus, may increase the risk of a pulmonary artery rupture.

Though advances in medical science have created improved therapies, often these are not widely provided throughout the health-care system. Also, there is growing recognition of the lack of safety in health-care delivery. The development of evidence-based, best practice, national guidelines has been encouraged to reduce unnecessary variation in care and for improving quality. Adoption of guidelines through local protocols has been disappointingly slow. This paper explores the parallel developments in safety and quality-of-care assessment, evidence-based medicine, guideline creation, and how development of national and international quality-improvement campaigns are promoting rapid change in care delivery processes. I discuss how this new opportunity can improve the quality of respiratory care and enhance the adoption of respiratory care protocols.

One of the most commonly performed procedures in the critically ill, tracheostomy has been described and used for lifesaving treatment of upper-airway obstruction for at least 3,500 years. The procedure can be performed surgically in the operating room or at the bedside in the intensive care unit. Recently, percutaneous techniques performed by a variety of specialists have become popular alternatives to open surgical tracheostomy. Various devices have been developed to minimize identified risk and improve the simplicity of the procedure. These techniques and devices are described in this paper.

Complications from surgical procedures are common and must be taken into account when assessing the risks and benefits of a particular treatment approach. Common acute risks of tracheostomy include bleeding, airway loss, damage to adjacent structures, and failure of the chosen technique to achieve successful airway placement. The frequency and severity of these occurrences depends on several factors. These include the specific approach to tracheostomy, the skill and experience of the operator, and patient anatomic and physiologic factors. The incidence of undesired outcomes during tracheostomy cannot be exactly predicted because of the interaction of the above issues. This paper will consider some of the common and less common acute complications of several of the usual techniques for temporary tracheostomy placement in critically ill patient.

Tracheostomy is one of the most common intensive care unit procedures performed. The advantages include patient comfort, safety, ability to communicate, and better oral and airway care. Patients may have shorter intensive care unit stays, days of mechanical ventilation, and hospital stays. There are risks, long-term and acute, and the timing of when to do a tracheostomy must be individualized. As soon as the need for prolonged airway access is identified, the tracheostomy should be considered. Generally, this decision can be made within 7-10 days. Bedside techniques allow rapid tracheostomy with low morbidity.

The interaction of a mechanical ventilator and the human cardiovascular system is complex. One of the most important effects of positive-pressure ventilation (PPV) is that it can decrease venous return. PPV also alters right- and left-ventricular ejection. Increased lung volume increases right-ventricular size by increasing pulmonary vascular resistance, causing intraventricular cardiac-septum shift, and decreasing left-ventricular filling. Increased intrathoracic pressure reduces afterload on the LV and increases ejection of blood from the LV. Understanding and managing these complex and often opposing interactions in critically ill patients is facilitated by analysis of hemodynamic and ventilator waveforms at the bedside. The relationship of PPV to changes in the arterial pressure waveform gives important information regarding appropriate fluid and vasopressor treatment. This article focuses on effects of respiratory pressures on hemodynamics and considers how cardiac pressures can be transmitted to the airway and cause ventilator malfunction.

In some situations, tables, graphs, and figures can present certain types of information (including complicated relationships and sequences of events) more clearly and in less space than the same information would require in sentence form. However, do not use tables, graphs, and figures for small amounts of data that could be conveyed clearly and succinctly in a sentence. Also, do not reiterate in sentences the data that are shown in a table, graph, or figure: the point of creating a table or graph or figure is to eliminate that type of sentence from your manuscript. In building a data table you must balance the necessity that the table be complete with the equally important necessity that it not be too complex. Sometimes it is helpful to break a large table into several smaller ones to allow the reader to identify important information easily, but, conversely, it is a common mistake of novice authors to split up into several tables data that belong in one table. In almost all cases, only one table or graph or figure should be included in an abstract, and then only if it can convey essential information in less space and in a more easily interpretable way than the sentence form. For a poster, in almost all instances you should use only one typeface and one font in a table, graph, or figure. In general, do not use bold, italics, or color unless you are presenting a great deal of data and you need to highlight certain data values and you are certain that using bold, italics, or color will improve readability, which is rare. Do not include identical information in a table and a graph/figure. In reporting a clinical trial you will need to include a patient flow chart that identifies the number of patients initially screened for the study, the number of patients who were excluded (and why) after initial screening or in the final analysis, and how many patients entered, exited early, and completed each arm of the study. A treatment protocol should also be described with a flow chart. In preparing a graph the most common error is to include a line that suggests an unsubstantiated extrapolation between or beyond the data points. In selecting the graph's axes, avoid truncating, enlarging, or compressing the axes in ways that might make the graph confusing or misleading. To prepare clear, accurate, easily interpretable tables, graphs, and figures, rely on the rules described in authoritative guides such as the Council of Science Editors' Scientific Style and Format and the American Medical Association's Manual of Style.

Having a questioning attitude is the fist step in the research process. Research begins with a question, which leads to a hypothesis. Questions abound in our daily clinical lives. Most quality research consists of comparisons. By carefully selecting a comparison group or condition, the quality of the research project can be improved. By including in the hypothesis the comparison group, the experiment can be focused and the analysis simplified. The best questions come from the investigator's subject of interest. When starting a research project, start small and choose an experienced mentor.

Prospective clinical research is given the greatest weight in evidence-based clinical practice recommendations, and therefore has the greatest potential to change care and help the largest number of patients. This article briefly describes the history of government regulation of prospective clinical research, how a prospective clinical research project is developed, and how the researcher seeks project approval from the institutional review board. We also evaluate 2 published studies with regard to ethical and regulatory matters that influenced the studies.

Evaluation of the impact on clinical care of improved, innovative oximetry technology.Randomized, prospective trial.Postcardiac surgery intensive care unit in a major teaching hospital.A total of 86 patients after undergoing coronary artery bypass surgery.All patients were monitored with two oximeters, one employing conventional oximetry (conventional pulse oximeter, CPO) and one using an improved innovative technology (innovative pulse oximeter, IPO), on different fingers of the same hand. The outputs from both devices were collected continuously by computer, but only one device was randomly selected and displayed for clinicians.The amount and percentage of nonfunctional monitoring time was collected and found to be much greater for the CPO than the IPO (8.7% +/- 16.4% for CPO vs. 1.2% +/- 3.3% for IPO, p =.000256). Time to extubation was not different between the two groups (634 +/- 328 mins for IPO vs. 706 +/- 459 mins for CPO). Clinicians managing patients with the more reliable IPO weaned patients faster to an FIO2 of 0.40 (176 +/- 111 mins for IPO vs. 348 +/- 425 mins for CPO, p =.0125), obtained fewer arterial blood gas measurements (2.7 +/- 1.2 for IPO vs. 4.1 +/- 1.6 for CPO, p =.000015), and made the same number of ventilator changes during this weaning process (2.9 +/- 1.2 for IPO vs. 2.9 +/- 1.7 for CPO).Provision of more reliable oximetry allows caregivers to act in a more efficient and cost-effective manner in regard to oxygen weaning and use of arterial blood gas measurements. Investigating the effect of a monitor on the process of care, rather than simply its accuracy and precision, is a useful, relevant paradigm for evaluating the value and impact of a new technology.

A common clinical observation is that patients wean more rapidly from mechanical ventilation following tracheotomy. Expected changes in tube resistance and dead space are not adequate to explain this observation in adult patients. Theoretical considerations are too complicated to allow evaluation of expected changes in work of breathing following tracheotomy. The resistance of the upper airway is about the same as breathing quietly through an 8.0 mm endotracheal tube; however, many patients experience a higher work of breathing following extubation. This is not true in infants, in whom the reduction in airway diameter is profound and a marked reduction in resistance is seen following extubation. The other benefits of tracheostomy include better secretion removal, improved oral hygiene, less laryngeal damage, and ability to eat and speak. These should be considered when proposing this procedure. There may be less late ventilator-associated pneumonia following early tracheotomy. The assumed better safety of tracheostomy has been questioned. That patients appear to wean more rapidly is probably accounted for by the variety of factors mentioned above.

Thirteen critically ill patients in the thoracic and cardiovascular ICU in whom conventional pulse oximetry (CPO) failed were identified and prospectively studied using an oximeter employing Masimo SET technology (MSO). These patients were elderly and ill, having undergone a variety of thoracic and cardiovascular operations. They were often hypothermic and shivering. Several had arterial assist devices, intraaortic balloon pumps or impending or actual cardiac arrest. In 12 of these patients the MSO was able to determine the actual arterial saturation as calculated from a coincident arterial blood gas. In the one patient, in whom no saturation was obtained with the MSO, no arterial blood could be obtained due to complete cardiac collapse. This case series demonstrates the value of the new Masimo SET technology for pulse oximetry in the most critically ill and demanding clinical situations in which other techniques have failed. A significant improvement in patient safety resulted from use of this improved oximetry.

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.

Temporary dual chamber atrioventricular (AV) pacing is often used to increase cardiac output (CO) after cardiac surgery. The AV interval was varied to investigate the effect on CO in 13 patients. CO was computed from the Fick principle using mixed venous oxygen saturation (SvO2), arterial oxygen saturation (SaO2), hemoglobin, and oxygen consumption (VO2). AV intervals were varied randomly from 0.025 to 0.300 seconds in 0.025-second increments. The effect on CO from increasing the AV interval was dependent on the control CO. In all patients, as the AV interval was increased from 0.025 to 0.100 seconds, CO progressively increased. In most patients, the highest (optimal) CO occurred with AV pacing and averaged 300 mL/min greater than with atrial (A) pacing alone (P.0001). In patients with a high initial CO (6.0 L/min), CO peaked and averaged 0.5 L/min more than with A pacing. CO was maximal for each of these patients at a unique AV interval between 0.100 and 0.225 seconds, and at intervals greater than 0.225 seconds CO decreased (P.01). In patients with intermediate CO (4-6 L/min) at AV intervals greater than 0.100 seconds, a plateau in CO was reached. No consistent pattern was seen in patients with low initial CO (4.0 L/min). Maximal CO may be achieved by optimizing the AV interval in patients following cardiac surgery. The optimal AV interval is between 0.100 and 0.225 seconds and is different for each patient. Continuous SvO2 monitoring allows rapid evaluation of CO changes and optimization of the AV pacing interval.

Acid base disorders—computer-aided learning software on CD-ROM consists of two clinical cases illustrating the use of acid-base analysis in clinical decision making. In an active form of learning, the student must make choices to confirm diagnoses and make management decisions. Tutoring and “consultation” with an expert are available throughout the entire process. Incorrect diagnoses are critiqued, and the user is directed to the “library” for additional study. Multiple-choice questions are presented throughout each scenario, and a record of student performance is displayed. Each case consists of five parts: brief history, clinical assessment, chemical assessment, diagnosis and treatment, and resolution–summary. Following the case, the student is presented with several brief cases and questions. A set of essay questions are …

The electronic explosion has resulted in a large number of medically oriented materials appearing for home computer use. Major medical book publishers have joined the rush to this market. Mosby's Pulmonary and Critical Care Medicine on CD-ROM, subtitled "your single source reference library," attempts to fill the gap between the dated material in current textbooks and up-to-date journal information. This CD-ROM contains the complete text and most of the graphs and charts fromPulmonary and Critical Care Loose-leaf, Year Book of Pulmonary Medicine(1993, 1994, 1995),Year Book of Critical Care Medicine(1993, 1994, 1995), andCurrent Pulmonology(volumes 14,15,16). The major advantage of this format over print is the ability to quickly search the material in a variety of ways to retrieve and organize the information in a userdefined way. The search engine is intuitive and rapid. Highlighting, custom bookmarks, and a reader-created note file linked to the

This CD-ROM produced by Churchill Livingstone medical publishers offers continuing medical education (CME) credit hours and an opportunity to review and practice resuscitation activities. The user interface is very hightech multimedia. A fast processor, sound card, CD-ROM drive, and at least 8 MB of RAM are necessary to fully appreciate the program's features. The stated educational goal of The Virtual Physician is to simulate an actual patient sustaining a cardiac arrest in an emergency department setting. Although the effects are excellent, the simulation fails to be realistic. This is not a fault of the concept but a problem of the computer-student interface, which is limited by unrealistic actions of a mouse or any pointing device. The program is true to the learning goals of traditional advanced cardiac life support (ACLS) courses, emphasizing the use of initial defibrillation in ventricular fibrillation and reviewing the arrhythmia treatment algorithms. The program offers several

To the Editor. —As the Executive Committee of the Board of Directors of American Society of Critical Care Anesthesiologists, the largest American subspecialty group of anesthesiologists and intensivists, we write to raise several points about the recent article by Dr Connors and colleagues on the RHC 1 and its accompanying Editorial. 2 We commend Connors et al for their attempt to examine the efficacy and safety of the RHC in a large cohort of critically ill (medical) patients. Their finding that the use of the RHC "was associated with an increased risk of mortality" certainly warrants further investigation. The explanations proposed by the authors are interesting, raising the possibility that the aggressive, interventional style of management practiced in some ICUs is hazardous rather than beneficial. An alternative explanation, that the "benefits of RHC may not be realized if the physician interpreting the output of the catheter is not knowledgeable and skilled in its

INTRODUCTION EXPERIMENTS herewith reported were made in connection with the investigational activities of the Food and Drug Administration to support enforcement of the Federal Food, Drug, and Cosmetic Act against misbranded drugs for livestock and poultry. When the occasion demands, remedies are tested on a “class basis” to evaluate their particular merit in a given field of disease. This can be done when many remedies in a particular category, which contain a common basic ingredient, are recommended for a specific disease or condition. In this instance, attention was drawn to almost universally made recommendations for copper sulfate as a remedy for crop mycosis in poultry caused by the fungus Candida albicans. Interest was concentrated in the validity of such recommendations when the literature revealed a paucity of factual evidence to support copper sulfate as a competent treatment of moniliasis (crop mycosis). This article presents critical information collected from the experimental …

THE use of synthetic estrogens for the hormonal fattening of poultry, and studies designed to demonstrate whether or not estrogenic residues remain in the edible tissues of the treated poultry have recently been reviewed by Lorenz (1954) and by Merker et al. (1955). Commercial use of the estrogens has been limited to the implantation or injection of stilbestrol and to the oral feeding of dienestrol diacetate. The usual practice is to treat the birds at 7 to 9 weeks of age and to slaughter the birds 4 to 6 week later. With the development of a sensitive assay method (Umberger, Gass and Curtis, 1958) based on the work of Stob, Andrews and Zarrow (1954), an examination has been made of the edible tissues from chickens treated with various commercial preparations of stilbestrol. The results of these assays are the subject of this report. A subsequent report will detail the studies …

Hydrochloric acid (HCl) infusions for the correction of metabolic alkalosis have been used for 20 yr. In the critical care setting, HCl is usually infused through a central venous or pulmonary artery (PA) catheter. In two patients receiving HCl infusions through a PA catheter, we observed and examined solid yellow particulate material in the aspirating syringe while testing the proximal lumen for patiency. We carried out in vitro investigation infusing PA catheters with 0.1, 0.2, 0.3, and 0.4 normal HCl at 20 degrees, 38 degrees, and 42 degrees C for 24 and 48 h. Although frank catheter deterioration could not be documented, the surface and interior of those catheters infused with greater than 0.1 normal HCl changed texture, indicating a change in catheter composition. Exceeding a concentration of 0.1 normal is not recommended when HCl is infused through PA catheters.

The effects of intravenous dantrolene sodium, alone and in combination with verapamil, upon atrioventricular conduction, cardiovascular function, and neuromuscular function were studied in chloralose-urethane anesthetized dogs. Hemodynamic variables (systemic arterial, central venous, and pulmonary arterial pressures and cardiac output) and His-bundle electrograms were monitored, and measurements were made during atrial pacing at 175 beats/min, as well as at the spontaneous heart rate. In one part of the study animals received dantrolene sodium incrementally at 30-min intervals to cumulative doses of 1, 2.5, 5, and 10 mg/kg. Subsequently, verapamil was administered incrementally at 30-min intervals to cumulative doses of 0.1, 0.2, 0.4, and 0.6 mg/kg. In the second part of the study, dogs received identical dosage sequences, but verapamil preceded dantrolene administration. Dantrolene caused no significant depression of atrioventricular conduction or cardiac performance but did increase systemic vascular resistance at doses above 2.5 mg/kg. Verapamil alone (greater than or equal to 0.2 mg/kg) or with dantrolene (greater than or equal to 0.1 mg/kg) increased the atrial-His-bundle conduction interval. In the presence of verapamil, dantrolene (greater than or equal to 2.5 mg/kg) decreased cardiac index and increased pulmonary artery occlusion pressure. Although 0.6 mg/kg verapamil depressed cardiac index and increased pulmonary artery occlusion pressure, this effect was observed at 0.4 mg/kg after prior treatment with dantrolene. Verapamil did not augment the dose-dependent twitch depression observed with dantrolene. Dantrolene alone had no apparent effect on atrioventricular conduction and caused little enhancement of the effects of verapamil. However, each drug appeared to enhance the myocardial depressant effects of the other.