Assessment of aspiration in patients with tracheostomies: comparison of the bedside colored dye assessment with videofluoroscopic examination.

BACKGROUND: Aspiration is a serious clinical concern in patients with long-term artificial airways. The purpose of this study was to determine the reliability of a bedside colored dye assessment of aspiration in tracheostomized patients and to determine its comparability to a more sophisticated videofluoroscopic study. METHODS: This was a prospective, blinded comparison study conducted in a large, urban, university teaching hospital. We studied 20 consecutive patients who underwent tracheostomy for bronchial hygiene needs and who were referred for videofluorographic evaluation for suspected oropharyngeal dysphagia and possible aspiration. Excluded were patients unable to follow verbal commands and those requiring mechanical ventilatory support. All patients were brought to the videofluorography suite for colored dye assessment for aspiration and videofluorographic assessment of oropharyngeal swallow. A nurse, blinded to the results of videofluorographic swallow study, performed colored dye assessments for aspiration. Speech-language pathologists, blinded to the results of the colored dye assessments, interpreted simultaneous (preliminary) and subsequent complete (final) videofluorographic evaluations of swallow. RESULTS: The colored dye aspiration assessments and the videofluoroscopic studies were compared for the frequency of aspiration detection. Sensitivity and specificity were determined using standard methods. Seven patients showed no aspiration on either the colored dye test or videofluoroscopic examination. Eight patients were judged to aspirate by videofluorography but not by the colored dye test. Five patients were judged to aspirate by both the colored dye test and videofluorography. The data indicate that the colored dye test for aspiration carries a low sensitivity of 38% (95% confidence interval = +/- 7%), but a high specificity of 100%. The videofluoroscopic study detected a significantly greater frequency of aspiration than did the colored dye test (p < 0.01). CONCLUSIONS: The colored dye test for aspiration can provide useful information when positive, but because there is a significant false negative rate, decisions made on the basis of a negative test must be made with caution.

Enhancing outcomes: guidelines, standards, and protocols.

Guidelines, protocols, and standards have gained attention as clinical tools designed to enhance clinical decision-making and practice. Yet, evidence has emerged that clinicians are having difficulty integrating new knowledge presented by these tools into practice. This article explores the benefits and barriers to using guidelines and protocols, probes the issues of producing these tools, and examines processes that are critical to constructing valid tools. The key functions important in successful development and implementation of guidelines and protocols are presented, as well as the direction these clinical adjuncts will take in the future.

Evaluation of an on-demand, ex vivo bedside blood gas monitor on pulmonary artery blood gas determinations.

Critically ill patients often have cardiopulmonary perturbations that require rapid and frequent assessment for optimal care, including cardiac output determinations, measurement of cardiac filling pressures, and arterial and mixed venous blood gas determinations. We evaluated the performance of a rapid, on-demand bedside blood gas monitor to determine arterial and mixed venous blood gas values. The blood gas monitor uses fluorescent optode technology to directly measure Po2, Pco2, and pH. This measurement is accomplished by aspirating blood from the artery or vein into a sampling chamber where it interfaces with the fluorescent optode. After approximately 90 s of equilibration, the blood gas values are reported. Since the blood is drawn into the sampling chamber, it can be returned to the patient, thus eliminating the need for phlebotomy. We studied 15 critically ill patients requiring systemic and pulmonary arterial catheterization. Conventional blood gas analysis was performed simultaneously. The results obtained from the blood gas monitor were compared with those obtained via traditional blood gas analysis using Bland-Altman plots and examination of bias and precision. The results were well within the expected clinical variance. During the study period, there was no interference with patient care or adverse events related to the use of the monitoring system. In conclusion, the blood gas monitor can provide rapid, accurate determinations of arterial and mixed venous blood gases allowing optimal therapeutic interventions in critically ill patients.

Diaphragm pacing with a quadripolar phrenic nerve electrode: an international study.

We sought to determine the international experience with the quadripolar diaphragm pacer system and to test two hypotheses: the incidence of pacer complications would be (1) increased among pediatric as compared to adult patients; and (2) highest among active pediatric patients with idiopathic congenital central hypoventilation syndrome (CCHS). Data were collected via a questionnaire coupled with the Atrotech Registry data for a total of 64 patients (35 children and 29 adults) from 14 countries. Thoracic implantation of electrodes and bilateral pacer use each occurred in 94% of all subjects. Tetraplegic (vs pediatric CCHS) patients were more typically paced 24 hours/day (P = 0.001). Pacing duration averaged 2.0 +/- 1.0 years among children and 2.2 +/- 1.1 years among adults. Infections occurred among 2.9% of surgical procedures, all in pediatric CCHS patients (vs pediatric tetraplegic patients, P = 0.01). The incidence of mechanical trauma was 3.8%, without significant differences among patient groups. The incidence of presumed electrode and receiver failure were 3.1% and 5.9%, respectively, with internal component failure greater among pediatric CCHS than pediatric tetraplegic patients (P < 0.01). Intermittent or absent function of 0-4 electrode combinations occurred among 19% of all patients, with increased frequency among pediatric CCHS than pediatric tetraplegic patients (P < 0.03). Complication-free successful pacing occurred in 60% of pediatric and 52% of adult patients. In all, 94% of the pediatric and 86% of the adult patients paced successfully after the necessary intervention. Although pacer complications were not increased among pediatric as compared to adult patients, the incidence of complications was highest among the active pediatric patients with CCHS. Longitudinal study of these patients will provide invaluable information for modification and improvement of the quadripolar system.

Microbial contamination of blood conservation devices during routine use in the critical care setting: results of a prospective, randomized trial.

OBJECTIVES: To compare microbial contamination of two different blood conservation devices; to determine if there was an association between contamination of the blood conservation devices and clinical infections; to determine if there was a significant user preference for either of the two devices. DESIGN: Prospective, randomized trial. SETTING: Medical, neurosurgical, and spinal cord intensive care units of an urban, university hospital. PATIENTS: Forty patients who required clinically indicated intrafierial catheters placed at new sites. INTERVENTIONS: The two most widely available blood conservation devices at the time of the study (Venous Arterial blood Management Protection system [VAMP], Baxter Edwards Critical-Care, Irvine, CA; and Safe Draw, Ohmeda, Madison, WI) were chosen for comparison. After the normal 48 to 72 hrs of device use, the blood conservation systems were removed and semi-quantitative and quantitative cultures were taken from comparable sites of the two devices. Positive cultures from the patients were recorded and correlated with cultures obtained from the devices. In order to assess preference for either device, a survey tool was administered to the nursing staff who participated in the study. MEASUREMENTS AND MAIN RESULTS: Quantitative cultures from all sites cultured in both groups demonstrated mean colony counts of < 10(3) colony-forming units (cfu)/mL. There were no statistically significant differences in the colony counts at any of the sites compared between the two groups. There were no statistically significant relationships between positive cultures and patient age, gender, duration of device utilization, frequency of device entry, or the intensive care unit in which the study was conducted. In no circumstance did positive cultures from any of the blood conservation devices correlate with positive culture results from any sites of clinical infection. The clinical survey demonstrated a statistically significant preference for the VAMP system, which persisted despite increased experience with the Safe Draw system. CONCLUSIONS: The levels of microbial contamination noted in these devices were not consistent with clinical infection (defined as 10(3) cfu/mL on quantitative cultures). There was no significant difference in degree or pattern of contamination between the two devices. When utilized and changed according to the Centers for Disease Control guidelines, blood conservation devices are not harbors of infection in the critical care setting. Blood conservation devices can be used as part of a comprehensive blood conservation program in the critical care setting without undue concern for exacerbating infectious processes.

Oxygen transport.

The most important factor in the development of complex life forms is the ability to deliver oxygen to cells within complex tissues and organs. Hemoglobin plays a significant role in this scheme. Oxygen transport is a complex phenomenon that encompasses the oxygen content, oxygen delivery mechanisms, and oxygen use. All three components must operate appropriately if the organism is to function and survive.

Blood gas monitors.

In vitro blood gas analysis requires limitation of the frequency of serial blood gas measurements for two major reasons--blood loss and cost. In vivo or ex vivo blood gas monitors eliminate these factors because the measurements are available continuously, or as frequently as deemed desirable, without permanently removing blood or imparting additional cost. For patients with arterial catheters in place, the propriety of blood gas monitors is obvious as long as there is no requirement to alter the size, location, or placement of the arterial catheter and the routine use of the arterial catheter system is unaffected. Further, personnel exposure to the patient's blood, and the risk of nosocomial infection from contaminated arterial catheters, should be reduced because the integrity of the arterial catheter and tubing system is not interrupted to obtain blood gas values. Blood gas monitors and point-of-care analyzers should significantly reduce therapeutic decision time (the interval from ordering the test to initiating a therapeutic action based on the test results), thereby enabling rapid titration of common therapeutic modalities such as oxygen administration, positive pressure ventilation, positive end-expiratory pressure, and manipulation of acid-base balance. The transfer of blood gas measurements from laboratory analyzers to the combination of blood gas monitors and point-of-care analyzers should have as profound an impact on acute care medicine as did the introduction of laboratory-based blood gas analysis over 30 years ago. In the current medico-economic environment, however, we must be certain that these devices are reliable, consistent, and cost beneficial in order to avoid widespread application of yet another technology that provides more data, greater costs, and only questionable patient benefits.

Bronchial hygiene therapy.

Bronchial hygiene therapy is useful and effective in the presence of careful patient evaluation, clear definition of therapeutic goals, and application of appropriate modalities. This article defines the variable bronchial hygiene modalities and discusses their indications, contraindications, and applications. Prophylactic and therapeutic bronchial hygiene modalities, diagnostic methods associated with bronchial hygiene therapy, inhaled antibiotic therapy, and therapist driven protocols are also addressed.

Safety of 1-stage bilateral total knee arthroplasty.

Bilateral total knee replacements during a single operation with intramedullary femoral guide rods have been associated with the possible development of a fat embolism syndrome. To assess the safety of this procedure, in which the femoral canal was decompressed by the use of an overdrilled entrance hole and fluted guide rod, 17 unilateral and 18 bilateral consecutive total knee patients were evaluated. There were no differences between the groups on the basis of changes in chest radiographs, percentage of estimated pulmonary shunting, mental status changes, or fat and bone marrow elements drawn from a central venous catheter in the right atrium. Although no patient had free fat in the blood, bone marrow elements were found in 3 bilateral and 2 unilateral cases. No patient had clinical manifestations of a fat emboli syndrome. With appropriate femoral canal decompression, bilateral 1-stage total knee replacement appears to be a safe procedure.

Hyponatremia in acute spinal cord injury.

OBJECTIVE: To define the occurrence rate, time course, and potential etiologic factors of hyponatremia in patients with acute spinal cord injury. DESIGN: Analysis of data obtained from a retrospective review of medical records and from a systematized, prospective database pertaining to patients with spinal cord injury. SETTING: A university hospital with a federally funded regional spinal cord injury center and a dedicated spinal cord injury intensive care unit. PATIENTS: Two hundred eighty-two patients admitted between January 1, 1988 and December 31, 1989 with acute (< 24-hr duration) spinal cord or vertebral column injury. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The mean age of patients was 36.7 +/- 17.6 (SD) yrs; 225 (80%) of the patients were male and 57 (20%) were female. Hyponatremia, when it occurred, developed at a mean time of 6.4 +/- 6.7 days postadmission, reached its nadir at 8.7 +/- 8.8 days, and occurred in 28% of those patients with cervical injuries, 34% with thoracic injuries, and 27% with lumbar injuries (p = NS). Logistic regression analysis demonstrated that the type of spinal cord injury (Frankel class: range is A = complete neurologic lesion to E = no neurologic lesion) was the strongest predictor of hyponatremia. The occurrence rate of hyponatremia was as follows: Frankel class-A 62%; Frankel class-B 48%; Frankel class-C 41%; Frankel class-D 23%; Frankel class-E 16% (p < .0001). CONCLUSIONS: The prevalence of hyponatremia in acute spinal cord injury is much higher than in the general medical or surgical patient population. This abnormality usually occurs within the first week postinjury. The most significant predictor of hyponatremia is the type rather than the level of spinal cord injury. The potential etiological factors are many and these factors are probably interrelated. The pathophysiological mechanisms that result in hyponatremia must be explored so that this occurrence and its consequences can be prevented.

A clinical evaluation of a blood conservation device in medical intensive care unit patients.

OBJECTIVES: This study was designed to a) document the efficacy of a device intended to conserve blood in critically ill patients; b) determine the effect of this blood conservation on hemoglobin concentration and the need for blood transfusions; c) determine if the blood conservation device resulted in interference with arterial pressure waveforms; d) determine if use of the blood conservation device resulted in a difference in the number of accidental needle punctures suffered by healthcare workers. DESIGN: Prospective, randomized, controlled trial. A clinical trial using prospective, random allocation of consecutive eligible patients. SETTING: The medical intensive care unit (ICU) of a university hospital located in a large metropolitan area. PATIENTS: A total of 100 patients who were admitted to the medical ICU, required arterial line monitoring for clinical purposes, and were managed by the ICU medical service. Exclusion criteria included active bleeding or chronic renal failure at the time of ICU admission. INTERVENTIONS: Patients in the experimental group had a blood conservation device incorporated into the arterial pressure monitoring system, while patients in the control group received a conventional arterial pressure monitoring system. MEASUREMENTS AND MAIN RESULTS: Data gathered included: age; gender; ICU discharge status; the duration of ICU stay; time in the study; volume of all blood drawn, discarded, or lost due to leakage; hemoglobin concentrations; blood transfusions; and accidental needle injuries. Arterial pressure waveforms were recorded and inspected for dampening or other deformation. Mean hemoglobin concentrations were compared on ICU admission and at 12-hr intervals. Demographic and clinical characteristics of the two groups were not significantly different. The volume of blood drawn and discarded from arterial catheters was significantly lower in the blood conservation group (blood conservation device: 5.7 +/- 7.5 mL; control: 96.4 +/- 88.5 mL; p < .0001), as was the total volume of blood discarded (blood conservation device: 19.4 +/- 47.4 mL; control: 103.5 +/- 99.9 mL; p < .0001). Mean hemoglobin concentration on admission was similar in the two groups (blood conservation device group: 11.8 +/- 2.5 g/dL; control group: 12.6 +/- 2.3 g/dL). In both groups, the mean hemoglobin concentration declined most rapidly in the first 24 hrs of ICU care and, thereafter, declined more slowly. Although the mean hemoglobin concentration was higher in the blood conservation group after 6 days, statistical significance was not reached until 9.5 days of ICU care. The mean change in hemoglobin concentration (overall: 1.2 +/- 2.2 g/dL) during the study represents a statistically significant (p < .0001) decrease of 9.7%. Hemoglobin concentration during the study decreased by 1.4 +/- 2.2 g/dL in the control group and 1.0 +/- 2.3 g/dL in the blood conservation group (p = nonsignificant). Univariate and multiple regression analysis demonstrated discarded blood volume to be a significant and independent predictor of the decline in hemoglobin concentration. Transfusion requirements were similar in both groups. The blood conservation system did not alter or interfere with pressure waveforms. There were no accidental needle injuries noted. CONCLUSIONS: The conservation of blood in critically ill patients must be a high-priority concern of all healthcare workers. Our data indicate that the blood conservation system eliminates a significant factor in the decline in hemoglobin concentration. With devices as described here, there is no reason to continue the practice of wasting the blood of critically ill patients in order to prevent preanalytic error.