Trace element homeostasis during continuous sedation with propofol containing EDTA versus other sedatives in critically ill patients.

OBJECTIVE: To evaluate changes in serum and urinary zinc, cobalt, copper, iron, and calcium concentrations in critically ill patients receiving propofol containing disodium edetate (disodium ethylenediaminetetraacetic acid [EDTA]) versus sedative agents without EDTA. DESIGN: This was a randomised, open-label, parallel-group study with randomisation stratified by baseline Acute Physiology and Chronic Health Evaluation (APACHE II) scores. SETTING: Intensive care units (ICU) in 23 medical centres. PATIENTS: Medical, surgical, or trauma ICU patients 17 years of age or older who required mechanical ventilator support and sedation. INTERVENTIONS: A total of 106 patients received propofol containing 0.005 % EDTA (propofol EDTA), and 104 received other sedative agents without EDTA (non-EDTA). Only the first 108 patients were assessed for urinary trace metal excretion. Twenty-four-hour urine samples were collected on days 2, 3, and 7 and every 7 days thereafter for determination of zinc, cobalt, copper, iron, and calcium excretion; EDTA levels; urine osmolality; albumin levels; and glucose levels. The first 143 patients were assessed for serum concentration of zinc, cobalt, copper, iron, and calcium; creatinine; blood urea nitrogen; and albumin at baseline and once during each 24-hour urine collection. MEASUREMENTS AND RESULTS: For the assessment of trace metals, patients receiving propofol EDTA demonstrated increased mean urinary excretion of zinc, copper, and iron compared with the normal range. All patients receiving sedatives demonstrated increased urinary excretion of zinc and copper above normal reference values. Compared with the non-EDTA sedative group, the propofol EDTA group demonstrated increased urinary excretion of zinc and iron. Mean serum concentrations of zinc and total calcium were decreased in both patient groups. Serum zinc concentrations increased from baseline to day 3 in the non-EDTA sedative group but not in the propofol EDTA group. Renal function, measured by blood urea nitrogen, serum creatinine, and creatinine clearance, did not deteriorate during ICU sedation with either regimen. CONCLUSION: This study showed that critical illness is associated with increased urinary losses of zinc, copper, and iron. Propofol EDTA-treated patients had greater urinary losses of zinc and iron and lower serum zinc concentrations compared with the non-EDTA sedative group. No adverse events indicative of trace metal deficiency were observed in either group. The clinical significance of trace metal losses during critical illness is unclear and requires further study.

Quantifying risk and assessing outcome in cardiac surgery.

Quality improvement, research, and reporting of outcome results can be stratified by preoperative risk by using a logistic regression equation or scores to correct for multiple risk factors. The more than 30-fold mortality differences between lowest and highest risk patients make it critical to stratify outcome results by patient severity. Probabilities are not predictions, however, and caution must be exercised when applying scores to individuals. Outcome assessment will grow in its importance to professionals, initially in the guise of quality reporting and improvement, but increasingly as a tool for risk assessment, patient counseling, and directing therapeutic decisions based on more complete information about patient subgroups. Physicians may be called on for recommendations in choosing systems for their hospitals and communities. Therefore, it is important to have an understanding of how such systems are developed, what factors indicate adequate performance of a system, and how such systems of risk stratification should be applied in practice.

Increased risk and decreased morbidity of coronary artery bypass grafting between 1986 and 1994.

BACKGROUND: The collective impact of advances in medical, surgical, and anesthetic care on the characteristics and outcomes of patients who undergo coronary artery bypass grafting was assessed. METHODS: We compared the demographic and clinical characteristics, preoperative risk factors, morbidity, and mortality of two groups of patients who underwent coronary artery bypass grafting in isolation or in combination with other procedures between July 1, 1986, and June 30,1988 (group 1, n = 5,051), and between January 1, 1993, and March 31, 1994 (group 2, n = 2,793). The patients were stratified according to their preoperative risk level. Outcome measures consisted of changes in preoperative risk categories; hospital mortality rates; overall and risk-adjusted major cardiac, neurologic, pulmonary, renal, and septic morbidity rates; and intensive care unit length of stay. RESULTS: Changes in the distribution of risk categories, from a median of 2 to 4 on a 9-point scale (p < 0.001), indicated that patients in group 2 were at significantly higher risk than those in group 1. The risk-adjusted mortality rate did not change (2.8% to 2.9%; p = 0.15), but the risk-adjusted morbidity rate decreased significantly (14.5% to 8.8%; p < 0.001). CONCLUSIONS: At our institution, patients who undergo coronary artery bypass grafting are now at greater preoperative risk at the time of hospital admission. However, their morbidity rate is significantly lower and their mortality rate is unchanged, results that we attribute to the collective impact of changes in our medical and surgical procedures.

ICU admission score for predicting morbidity and mortality risk after coronary artery bypass grafting.

BACKGROUND: This study was performed to develop an intensive care unit (ICU) admission risk score based on preoperative condition and intraoperative events. This score provides a tool with which to judge the effects of ICU quality of care on outcome. METHODS: Data were collected prospectively on 4,918 patients (study group n = 2,793 and a validation data set n = 2,125) undergoing coronary artery bypass grafting alone or combined with a valve or carotid procedure between January 1, 1993, and March 31, 1995. Data were analyzed by univariate and multiple logistic regression with the end points of hospital mortality and serious ICU morbidity (stroke, low cardiac output, myocardial infarction, prolonged ventilation, serious infection, renal failure, or death). RESULTS: Eight risk factors predicted hospital mortality at ICU admission, and these factors and five others predicted morbidity. A clinical score, weighted equally for morbidity and mortality, was developed. All models fit according to the Hosmer-Lemeshow goodness-of-fit test. This score applies equally well to patients undergoing isolated coronary artery bypass grafting. CONCLUSIONS: This model is complementary to our previously reported preoperative model, allowing the process of ICU care to be measured independent of the operative care. Sequential scoring also allows updated prognoses at different points in the continuum of care.

The risk of coronary artery surgery in women: a matched comparison using preoperative severity of illness scoring.

OBJECTIVE: To evaluate the effect of gender on outcomes of coronary artery bypass surgery using a weighted preoperative severity of illness scoring system. DESIGN: Retrospective database review. SETTING: Tertiary care teaching hospital. PARTICIPANTS: The patient population consisted of 2,800 consecutive coronary artery bypass graft (CABG) patients (658 women, 2,142 men), with or without concurrent procedures, operated on between January 1, 1993 and March 31, 1994. MEASUREMENTS AND MAIN RESULTS: Patients were stratified for severity of illness using a 13-element scoring system. The distribution of severity of illness scores and severity of illness-stratified morbidity, hospital mortality, and intensive care unit (ICU) length of stay were compared by chi-square and Fischer's exact test where appropriate. Median duration of intubation and median duration of ICU length of stay were examined by the median test. Female versus male unadjusted mortality (4.9% v 3.0%), total morbidity (15.0% v 9.2%), and average initial ICU length of stay (92.62% v 60.56 hours) were statistically different. Female patients also had significantly more of the following postoperative morbidities: central nervous system complications (focal neurologic deficits, patients > or = 65 years 3.20% v 1.54%; global neurologic deficits, patients > or = 65 years 2.75% v 1.25%), duration of perioperative ventilation that includes the intubation time in the operating room until extubation in the ICU (average = 77.36 hours v 49.20 hours; median = 21.87 v 20.26 hours), and average initial ICU length of stay (average = 92.62 hours v 60.56 hours; median = 42.33 hours v 27.91 hours). However, distribution of severity scores was also different. Women had significantly more preoperative risk factors (p < 0.05): age 65 to 74 years (45.1% v 36.6%), age > or = 75 years (21.3% v 11.9%), chronic obstructive pulmonary disease (10.8% v 6.4%), hematocrit less than 34% (21.9% v 5.5%), diabetes (34.8% v 21.8%), weight less than 65 kg (37.4% v 6.2%), and operative mitral valve insufficiency (9.6% v 6.0%). Stratified by severity, no statistically significant gender differences were found for mortality, morbidity, or ICU length of stay. CONCLUSIONS: Gender does not appear to be an independent risk factor for perioperative morbidity, mortality, or excessive ICU length of stay when patients are stratified by preoperative risk in this severity of illness scoring system.

Conscious sedation: what an internist needs to know.

The use of conscious sedation instead of general anesthesia is increasing with the development of less-invasive alternatives to surgery and the shift to outpatient care. Yet, conscious sedation can pose its own special dangers. Common pitfalls include failure to recognize hypoxemia, inadequate analgesia, inappropriate dosing with respect to individual variability, and lack of appropriate backup support.

Immediate postoperative care of cardiac surgical patients.

Anesthetic care of the cardiac surgery patient is a continuum, beginning with the preoperative visit and ending when the patient is ambulatory and breathing well on the postoperative floor. Anesthesiologists are well-suited to provide postoperative care because the respiratory and cardiovascular management techniques are an extension of OR management. Attention to details is as important in the ICU as in the OR and offers the opportunity to forestall or reduce morbidity.

Safety issues regarding early extubation after coronary artery bypass surgery.

Potential safety issues related to early extubation include the effect of changes in anesthetic management on intraoperative hemodynamics, stress responses and awareness, altered management in the control of pain, shivering and ischemia in the early postoperative period, and the risks of reintubation in patients who might require reoperation for bleeding. The literature does not implicate any technique necessary to facilitate early extubation as being associated with adverse outcome. Definitive outcome studies are only beginning to be presented, but the data so far suggest that early extubation is not associated with any increase risk of mortality or morbidity, including, specifically, myocardial ischemia or infarction. These studies of early extubation have involved selected patients, and it is unknown but unlikely that early extubation can be recommended for all patients, particularly those who might be at risk for perioperative ischemia as the result of inadequate myocardial protection, unsatisfactory surgery, or other factors yet to be identified. In the absence of definitive studies, it may be prudent to manage high-risk patients with a more conservative approach. Complications such as low cardiac output, arrhythmias, stroke, and perioperative myocardial infarction have not increased with early extubation, at least in patients selected for early extubation on the basis of preoperative characteristics. In summary, available evidence suggests that early extubation, applied to many but probably not all patients, can be accomplished without demonstrable patient harm. A coordinated approach involving anesthesia, surgery, nursing, respiratory therapy, and other support services is essential, and constant reevaluation as events unfold, rather than rigid protocols, allows care to be individualized to the specific needs of each patient.

The use of APACHE III to evaluate ICU length of stay, resource use, and mortality after coronary artery by-pass surgery.

OBJECTIVE: To identify patient characteristics that are associated with increased ICU length of stay, resource use, and hospital mortality after coronary artery bypass surgery. DESIGN: Prospective, multicenter study. SETTING: Six tertiary care hospitals. PARTICIPANTS: A consecutive sample of 2,435 unselected ICU admissions following coronary artery by-pass surgery. MATERIALS AND METHODS: Demographic, operative characteristics and APACHE III score were collected during the first postoperative day; and APACHE III scores and therapeutic interventions during the first three postoperative days. Hospital survival and ICU length of stay were also recorded. Multivariate equations were derived and cross-validated to predict hospital mortality, ICU length of stay, and ICU resource use. RESULTS: Unadjusted hospital mortality rate was 3.9% (range 1.0% to 6.0%), mean ICU length of stay was 3.7 days (range 3.2 to 4.7 days), and first 3-day ICU resource use (TISS points) was 99 (range 68 to 116). The range of actual to predicted ICU length of stay varied from 0.86 to 1.26; and resource use from 0.71 to 1.16. CONCLUSIONS: A limited number of operative characteristics, the post-operative acute physiology score (APS) of APACHE III and patient demographic data can predict hospital death rate, ICU length of stay, and resource use immediately following coronary by-pass surgery. These estimates may compliment assessments based on pre-operative risk factors in order to more precisely evaluate and improve the efficacy and efficiency of cardiovascular surgery.

Propofol versus midazolam for intensive care unit sedation after coronary artery bypass grafting.

OBJECTIVE: To compare the safety and effectiveness of propofol (2,6-diisopropylphenol) to midazolam for sedation of mechanically ventilated patients after coronary artery bypass grafting. DESIGN: Open, randomized, prospective trial. SETTING: Cardiothoracic intensive care unit (ICU), Cleveland Clinic Foundation. PATIENTS: Eighty-four patients with normal or moderately impaired left ventricular function who underwent elective coronary artery bypass graft surgery under high-dose opioid anesthesia. INTERVENTIONS: Patients were randomly selected to receive either propofol (mean loading dose 0.24 mg/kg; mean maintenance dose 0.76 mg/kg/hr) or midazolam (mean loading dose 0.012 mg/kg; mean maintenance dose 0.018 mg/kg/hr). Infusion rates were titrated to keep patients comfortable, drowsy, and responsive to verbal stimulation. Study duration, 8 to 12 hrs; infusions were started in the ICU when patients were awake and hemodynamically stable. MEASUREMENTS AND MAIN RESULTS: During therapy, both groups had lower mean arterial pressures and heart rates compared with baseline measurements; however, the propofol group had significantly lower heart rates than the midazolam group during the first 2 hrs of infusion. The propofol group also had significantly lower blood pressure measurements 5 and 10 mins after the initial dose, although there was no difference during infusion. Baseline cardiac output was measured before starting the infusion, and measurements were repeated during continuous infusion at 4, 8, and 12 hrs. Cardiac output values were similar. Propofol maintenance infusions ranged from 3 to 30 micrograms/kg/min and midazolam infusions ranged from 0.1 to 0.7 micrograms/kg/min. At these infusion rates. both groups had adequate sedation, based on nurse and patient evaluations; however, the propofol group used significantly lower total doses of sodium nitroprusside and supplemental opioids. CONCLUSIONS: Both propofol and midazolam provided safe and effective sedation of coronary artery bypass graft patients recovering from high-dose opioid anesthesia. The reduced need for both antihypertensive medication and opioids seen in the propofol group may be advantageous. However, the hypotension seen after the initial bolus dose of propofol may be a concern. No difference between the two drugs could be demonstrated in time to extubation or ICU discharge, although it is probable that time to extubation was governed more by residual operative opioids than the study agents.

Acute dialytic support of the octogenarian: is it worth it?

Dialytic support of the elderly has recently come under scrutiny. The consumption of resources and the lack of clear data on outcome have fueled the controversy. In an effort to establish a baseline, we reviewed our experience over the past 5 years of ICU dialysis therapies delivered to patients over 80 years old. Data were prospectively collected for an ICU Renal Registry and included admission diagnosis, presence of pre existing renal dysfunction (serum creatinine > or = 1.5 mg/dl), APACHE score at both ICU entry (A1) and consultation (A2), presence of multiorgan failure (MOF), pressor support (PS), nutritional support (NS), therapy type used (both prescribed and delivered), and outcome, either as ICU discharge, return of renal function, or withdrawal. A total of 21 patients (average age 82.6; range, 80-88 years) consisting of 4-8% of the yearly consultations underwent renal replacement therapy. The majority of patients were surgical (20/21); 61.9% had pre-existing renal dysfunction (serum creatinine 2.1 +/- 1.4 mg/dl) and presented with ARF from ischemic/toxic causes (17/21) or other causes (4/21). Virtually all patients had MOF (20/21) with moderately elevated APACHE scores (A1: 20.9, A2: 21.3). Eighty-six percent received PS, and 90% received NS. Renal therapy consisted of only intermittent (9/21), only continuous (4/21), or a combination (8/21). These data were compared with those of 80+ year old patients who underwent surgery but did not require dialysis, as well as with those of non 80 year old dialysis supported ICU patients over the same 5 year period. Patient outcome reflected a 33.3% overall survival and a 28.5% renal recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

The changing profile of anesthetic practice: an update for internists.

BACKGROUND: Internists are commonly consulted to "clear" patients for anesthesia and surgery. Newer anesthetic agents and techniques now extend limits and possibilities beyond what many internists were taught. OBJECTIVE: To update internists on recent changes in anesthetic management and how they affect the preoperative evaluation. SUMMARY: Recent advances in anesthetic management include new monitoring standards, balanced anesthetic technique, new agents, equipment changes, better understanding of human factors, and expanded pain management techniques. CONCLUSIONS: Postoperative care will likely assume increasing importance in determining anesthesia-related morbidity and mortality. For this reason, increased interaction and cooperation between surgeons, internists, and anesthesiologists are needed.

Unilateral auto-PEEP in the recipient of a single lung transplant.

We report a patient who received a right single lung transplant (SLT) for progressive lymphangioleiomyomatosis and required reintubation for postoperative respiratory distress. She developed hemodynamic instability due to mediastinal shift from unilateral auto-PEEP with hyperinflation of the native lung. Placement of a double lumen endotracheal tube (DLET) and institution of differential lung ventilation restored equal lung inflation and hemodynamic stability.

Myocardial protection during cardiac operations. Decreased morbidity and lower cost with blood cardioplegia and coronary sinus perfusion.

The efficacy of myocardial protection with a single aortic crossclamp and blood cardioplegia was evaluated in 819 consecutive patients stratified for preoperative condition by means of a new clinical risk scoring system. A protocol using either antegrade or antegrade/retrograde blood cardioplegia was compared with antegrade crystalloid cardioplegia in 2582 similar, consecutive, and concurrent patients. In the blood cardioplegia cohort, 97 (11.8%) patients had 129 complications compared with 407 (15.8%) patients and 675 complications in the crystalloid cardioplegia group (p = 0.006). In high-risk patients, combined antegrade/retrograde cardioplegia significantly reduced myocardial infarction, stroke, and respiratory and wound complications. Despite the significantly longer aortic crossclamp time required for blood cardioplegia, patients undergoing crystalloid cardioplegia were 1.7 (95% confidence interval 1.3, 2.1) times more likely to have a morbid event. Time in the intensive care unit, length of hospitalization, and length-of-stay outlier status were significantly decreased in the blood cardioplegia compared with the crystalloid cardioplegia group. The net savings in hospital cost amounted to $2196 per case. When compared separately with crystalloid cardioplegia, combined antegrade/retrograde blood cardioplegia accounted for most of the morbidity reduction by significantly reducing perioperative myocardial infarction, wound complications, and length of stay in patients having reoperations. Antegrade/retrograde blood cardioplegia did not influence 1-year survival or event-free survival, even when risk was considered.

Pro: early endotracheal extubation is preferable to late extubation in patients following coronary artery surgery.

Prolonged mechanical ventilation following CABG should not be uncritically considered "routine," and should only be used where indicated. A thorough physiologic and clinical evaluation with attention to hemodynamics, neurologic status, temperature and metabolism, hemostasis, and respiratory reserve should precede extubation. Continued post-operative ventilation is indicated in patients at high risk for complications, and it is possible to identify this subset preoperatively and upon arrival in the postoperative ICU. Early extubation (within 8 hours of arrival) should otherwise be the goal. The benefits of early extubation include improved cardiac function and patient comfort, reduction in respiratory complications, ease in management, and cost savings as the result of shortened length-of-stay in expensive postoperative units. More research is needed to clarify unanswered questions regarding ablating the stress response and avoiding myocardial ischemia.

Total electrical power failure in a cardiothoracic intensive care unit.

OBJECTIVE: To describe the management of patients in an ICU during failure of both primary and backup electrical systems, resulting in nonfunctioning monitors, mechanical ventilators, and other life-support equipment. DESIGN: Case report of power outage and discussion. SETTING: A 45-bed cardiothoracic surgical ICU in a tertiary-care teaching hospital. PATIENTS: Postoperative cardiothoracic surgical patients receiving i.v. infusions of vasoactive medications and mechanical ventilatory support. MAIN RESULTS: Support measures included the use of pneumatically powered mechanical ventilators, battery-operated transport monitors and infusion pumps, and recruitment of non-ICU personnel to assist with manual ventilation and patient care. Problems identified included communication difficulties caused by failure of electronic telephones, and physical access limitation due to failure of electrical door openers and security locks. CONCLUSIONS: Total electrical power failure can occur even when an emergency power system is in place. Although the occurrence of such failure is unlikely, provisions must be made for its occurrence in order to avoid catastrophic patient injury. Such provisions include a mental plan of action, provision of emergency support equipment, physical plant changes, and the provision of power-independent communication systems. Power demands and battery backup capability of equipment should be considered in future equipment purchases. The ICU staff should be aware of the structure and operation of backup electrical power sources.