Sedation after cardiac bypass surgery: comparison of propofol and midazolam in the presence of a computerized closed loop arterial pressure controller

Predictors of severe hypotension in neurocritical care patients sedated with propofol

INTRODUCTION

Propofol is used extensively in neurocritical care (NCC) due to its pharmacologic properties allowing for facilitation of serial neurologic examinations. Despite widespread use, few studies have identified risk factors for hypotension in these patients. We aimed to determine predictors of hypotension in NCC patients sedated with propofol.

METHODS

This retrospective, multicenter study evaluated 237 patients at two academic medical centers, both with dedicated NCC teams led by board-certified neurointensivists. Univariate analyses were performed to determine risk factors associated with severe hypotension during sedation with propofol. Multivariable analysis was performed to determine variables independently associated with hypotension, defined as a mean arterial pressure (MAP) less than 60 mmHg.

RESULTS

There was an average maximum reduction in MAP of 28.8 % after propofol initiation in the entire cohort. Severe hypotension developed in 62 (26.2 %) patients to a median nadir MAP of 56 mmHg. Those who developed severe hypotension had a longer median duration of mechanical ventilation (5.0 vs. 3.6 days; p = 0.01) and an increased in-hospital mortality (38.7 vs. 24.0 %; p = 0.03). Multivariable logistic regression analysis identified increasing number of changes to the propofol infusion rate, baseline MAP 60-70 mmHg, and need for renal replacement therapy (RRT) as factors independently associated with hypotension.

CONCLUSIONS

Multiple factors predicted hypotension in NCC patients receiving propofol. Clinicians should use propofol cautiously in patients with a lower baseline MAP or receiving RRT. Development of protocols related to the frequency of dose titrations is also recommended to prevent this avoidable complication.

Principles of pharmacologic hemodynamic management and closed-loop systems

Every day, physicians in critical-care settings are challenged with the hemodynamic management of patients with severe cardiovascular derangements. There is a potential role for closed-loop (automated) systems to assist clinicians in managing these patients and growing interest in the possible applications. In this review, we discuss the basic principles of critical-care hemodynamic management and the closed-loop systems that have been developed to help in this setting.

Predictors of severe hypotension in neurocritical care patients sedated with propofol

INTRODUCTION

Propofol is used extensively in neurocritical care (NCC) due to its pharmacologic properties allowing for facilitation of serial neurologic examinations. Despite widespread use, few studies have identified risk factors for hypotension in these patients. We aimed to determine predictors of hypotension in NCC patients sedated with propofol.

METHODS

This retrospective, multicenter study evaluated 237 patients at two academic medical centers, both with dedicated NCC teams led by board-certified neurointensivists. Univariate analyses were performed to determine risk factors associated with severe hypotension during sedation with propofol. Multivariable analysis was performed to determine variables independently associated with hypotension, defined as a mean arterial pressure (MAP) less than 60 mmHg.

RESULTS

There was an average maximum reduction in MAP of 28.8 % after propofol initiation in the entire cohort. Severe hypotension developed in 62 (26.2 %) patients to a median nadir MAP of 56 mmHg. Those who developed severe hypotension had a longer median duration of mechanical ventilation (5.0 vs. 3.6 days; p = 0.01) and an increased in-hospital mortality (38.7 vs. 24.0 %; p = 0.03). Multivariable logistic regression analysis identified increasing number of changes to the propofol infusion rate, baseline MAP 60-70 mmHg, and need for renal replacement therapy (RRT) as factors independently associated with hypotension.

CONCLUSIONS

Multiple factors predicted hypotension in NCC patients receiving propofol. Clinicians should use propofol cautiously in patients with a lower baseline MAP or receiving RRT. Development of protocols related to the frequency of dose titrations is also recommended to prevent this avoidable complication.

Evaluation of propofol as a general anesthetic agent for minor oral surgical procedure

Nausea and vomiting following anesthesia is a distressing problem for the patient as it increases the recovery time, intensity of nursing care and delays discharge. The aim of randomized controlled single blind study is to evaluate the efficacy and safety of subhypnotic doses of propofol for the prevention of postoperative nausea and vomiting (PONV) in day care management of cases in oral and maxillofacial surgeries. Twenty-five patient of ASA-1 with age ranging from 12 to 40 years were scheduled for various maxillofacial surgical cases like fracture, cyst enucleation, surgical removal of 3rd molar, etc. were given propofol at the dose of 2 to 2.5 mg/kg as induction dose and sedation was maintained with the dose 5 to 10 mg/min. There was no significant effect on heart rate, systolic and diastolic blood pressure, respiratory rate and oxygen saturation intraoperatively. In conclusion, a subhypnotic dose of propofol is fast acting, safe and easily controllable, short acting general anesthetic agent with rapid recovery. The study found that the PONV was significantly reduced in the patient with propofol, no hemodynamic derangements were noted in the postoperative period.

Sedation for critically ill or injured adults in the intensive care unit: a shifting paradigm

As most critically ill or injured patients will require some degree of sedation, the goal of this paper was to comprehensively review the literature associated with use of sedative agents in the intensive care unit (ICU). The first and selected latter portions of this article present a narrative overview of the shifting paradigm in ICU sedation practices, indications for uninterrupted or prolonged ICU sedation, and the pharmacology of sedative agents. In the second portion, we conducted a structured, although not entirely systematic, review of the available evidence associated with use of alternative sedative agents in critically ill or injured adults. Data sources for this review were derived by searching OVID MEDLINE and PubMed from their first available date until May 2012 for relevant randomized controlled trials (RCTs), systematic reviews and/or meta-analyses and economic evaluations. Advances in the technology of mechanical ventilation have permitted clinicians to limit the use of sedation among the critically ill through daily sedative interruptions or other means. These practices have been reported to result in improved mortality, a decreased length of ICU and hospital stay and a lower risk of drug-associated delirium. However, in some cases, prolonged or uninterrupted sedation may still be indicated, such as when patients develop intracranial hypertension following traumatic brain injury. The pharmacokinetics of sedative agents have clinical importance and may be altered by critical illness or injury, co-morbid conditions and/or drug-drug interactions. Although use of validated sedation scales to monitor depth of sedation is likely to reduce adverse events, they have no utility for patients receiving neuromuscular receptor blocking agents. Depth of sedation monitoring devices such as the Bispectral Index (BIS©) also have limitations. Among existing RCTs, no sedative agent has been reported to improve the risk of mortality among the critically ill or injured. Moreover, although propofol may be associated with a shorter time to tracheal extubation and recovery from sedation than midazolam, the risk of hypertriglyceridaemia and hypotension is higher with propofol. Despite dexmedetomidine being linked with a lower risk of drug-associated delirium than alternative sedative agents, this drug increases risk of bradycardia and hypotension. Among adults with severe traumatic brain injury, there are insufficient data to suggest that any single sedative agent decreases the risk of subsequent poor neurological outcomes or mortality. The lack of examination of confounders, including the type of healthcare system in which the investigation was conducted, is a major limitation of existing pharmacoeconomic analyses, which likely limits generalizability of their results.

Validation of a consciousness level scale for palliative care

The main objective of this study is to validate a Consciousness Scale for palliative care. The scale was named Consciousness Scale for palliative care (CSPC). The validation had two phases: 1) face validity--the scale was assessed by seven healthcare professionals, both doctors and nurses, experienced in palliative care; 2) reliability and construct validity--performed by four investigators, two nurses and two doctors. The construct validation was performed by comparing the CSPC with a Visual Analogue Scale (VAS) of 100 mm, anchored in the terms 'awake' and 'unarousable', and then with the Glasgow Coma Scale (GCS). In this study, all four observers completed 44 periods of observation relative to 38 patients resulting in a total of 176 observations. In the phase of face validation, there were no discrepancies in relation to the issue: the scale provides measures for measurement; the scale can be useful to clinical practice; the scale can improve communication among professionals and the scale is easy to use. As a measure of internal consistency, Cronbach's alpha was found to be very high (0.99). The inter-rater reliability was also very high with an intraclass correlation coefficient of 0.99 (P < 0.001). The correlation of the CSPC to the VAS was 0.94 (P < 0.001) and the CSPC to the GCS was -0.82 (P < 0.001). The CSPC can be a very useful tool for assessing consciousness in palliative care patients. It is very ease to use, not time consuming and can be used with minimal training. Communication between professionals can be improved in the clinical setting and in the research environment.

Economic evaluation of sustained sedation/analgesia in the intensive care unit

Lorazepam, midazolam, propofol and opioids are the primary agents that are used for sustained sedation and analgesia of critically ill patients. The choice of agent depends on safety profiles, expected outcomes, cost, patient characteristics and clinical experience. Few studies have comparatively evaluated the sedatives in terms of cost. Many factors, aside from drug costs, influence the total cost of sedation in the intensive care unit. This article reviews the cost parameters of intensive care unit sedation that are specific to the characteristics of commonly used sedatives and analgesics, evaluates economic studies and cost models, summarises alternative methods of sedation and analgesia, and provides practical recommendations for methods of cost containment, including daily sedation interruption, sedation monitoring and protocol implementation.

Pharmacoeconomic Modeling of Lorazepam, Midazolam, and Propofol for Continuous Sedation in Critically Ill Patients

STUDY OBJECTIVE

To compare the expected costs of short-, intermediate-, and long-term sedation (< 24, 24-72, and > 72 hrs, respectively) with propofol, lorazepam, and midazolam in an intensive care unit.

METHODS

Decision-analysis models were constructed for each sedative and each duration by using institutional costs associated with drug administration and adverse events (including personnel time). Costs were expressed in 2002 U.S. dollars. Adverse events were agitation, hypertriglyceridemia and/or pancreatitis, hypotension, nutritional changes, ventilator-associated pneumonia, and prolonged awakening and/or extubation. MEDLINE and EMBASE databases were searched to obtain durations of sedation, the incidence of outcomes, and cost estimates of outcomes. The ability to maintain specific levels of sedation was assumed equivalent among the sedatives. Univariate sensitivity analyses were conducted to determine the cost-driving variables, and probabilistic sensitivity analyses were conducted by using second-order Monte Carlo simulations.

RESULTS

Weighted mean durations of sedation from 50 studies were 13.46 (short term), 45.27 (intermediate term), and 119.78 (long term) hours. Expected costs for sedation with lorazepam, midazolam, and propofol, respectively, were 497 dollars, 294 dollars, and 272 dollars short term; 932 dollars, 587 dollars, and 674 dollars intermediate term; and 1604 dollars, 1737 dollars, and 2033 dollars long term. Propofol was least costly in 86% of the short-term simulations, midazolam was least costly in 97.5% of the intermediate-term simulations, and lorazepam was least costly in 84% of the long-term simulations. The most important cost-driver for all sedatives was drug cost. Prolonged extubation after sedation was an important cost-driver for lorazepam and midazolam, especially as sedation was lengthened.

CONCLUSION

Propofol, midazolam, and lorazepam had the lowest expected costs for short-, intermediate-, and long-term sedation, respectively. Many factors aside from drug costs influenced the cost of sedation.

Do intraoperative variables have an effect on the timing of tracheal extubation after coronary artery bypass graft surgery?

OBJECTIVE

The purpose of this study was to investigate whether any intraoperative variable had a significant effect on extubation time after coronary artery bypass graft surgery.

DESIGN

Study design was a retrospective study.

SETTING

Study took place in 1 cardiac center in the United Kingdom that had 1000 cases per year.

SUBJECTS

Eighty-nine patients had coronary artery bypass graft surgery in the first 6 months of 1998 performed by one consultant cardiac surgeon.

OUTCOME MEASURES

Study measures included intraoperative variables (number of vessels grafted, time on cardiopulmonary bypass [CPB], length of the operation, use of internal mammary artery) and extubation time.

RESULTS

Mean extubation time was 4.97 hours. On analysis via linear regression no intraoperative variables were found to be statistically significant (P = .05) to extubation time.

CONCLUSION

This study identified that early extubation can be achieved safely. Although no variable was found to have a significant effect on extubation time, the relationship between CPB and extubation may have been attributed to the low mean CPB time within the study (49.1 minutes). The relationship between cardiac status, ischemia, and the timing of extubation does warrant additional exploration.

Sedation assessment in critically ill adults

OBJECTIVE

To review methods for assessing sedation in critically ill adults, discuss their impact on patient outcomes, and provide recommendations for implementing these methods into clinical practice in the intensive care unit (ICU).

DATA SOURCES

A computerized search of MEDLINE from 1980 through June 2000 and a manual search of abstracts presented at recent critical care meetings were performed.

STUDY SELECTION AND DATA EXTRACTION

Sedation assessment tools that have been used to titrate therapy in adult, critically ill patients were identified. Special emphasis was placed on sedation assessment instruments that have been prospectively validated. Objective methods that have been used to assess sedation therapy were also identified.

DATA SYNTHESIS

Twenty-three adult sedation assessment instruments were identified. Few scales have been prospectively evaluated for validity (n = 6) or reliability (n = 7). Other methods of sedation assessment were identified (e.g., bispectral index monitor); however, most of these methods have only been studied in small subsets of critically ill patients.

CONCLUSIONS

Incorporation of sedation assessment into ICU clinical practice may improve patient care. These sedation assessment instruments must be further evaluated to determine their impact on quality of care and ICU length of stay.

Propofol or midazolam--which is best for the sedation of adult ventilated patients in intensive care units? A systematic review

Intensive care patients are commonly sedated to maintain comfort and to facilitate life saving therapy. Although sedation is ordered by medical staff, nurses are usually responsible for its administration and titration and thus the question of which drug regime should be chosen is an important practice issue for nurses (1,2). This paper is a report on a systematic review that was conducted to compare the effectiveness of two of the most common drugs used for the sedation of adult ventilated patients in Australian intensive care units (ICUs)--propofol and midazolam (3). All randomised controlled trials (RCTs) which compared propofol with midazolam for the sedation of adult ventilated patients in ICUs were included in the study. The outcome measures evaluated were the quality of sedation achieved, the length of time from cessation of sedation till extubation, recovery time, duration of admission to the ICU and the incidence of haemodynamic complications. Meta-analysis was used to compare results of studies where subjects had the same characteristics and the outcome criteria were measured in the same manner. The review found that infusions of both midazolam and propofol appear to provide similar quality sedation, that extubation time and recovery time is shorter in patients sedated with propofol and that haemodynamic complications related to either drug regime are not usually clinically significant.

A lack of evidence of superiority of propofol versus midazolam for sedation in mechanically ventilated critically ill patients: a qualitative and quantitative systematic review

Propofol and midazolam are often used for sedation in the intensive care unit. The aim of this systematic review was to estimate the efficacy and harm of propofol versus midazolam in mechanically ventilated patients. A systematic search (Medline, Cochrane Library, Embase, bibliographies), any language, up to June 1999 was performed for reports of randomized comparisons of propofol with midazolam. Data from 27 trials (1624 adults) were analyzed. The average duration of sedation varied between 4 and 339 h. In 10 trials, the duration of adequate sedation was longer with propofol (weighted mean difference 2.9 h; 95% confidence interval [CI], 0.2-5.6 h). In 13 trials (mostly postoperative), sedation lasted 4 to 35 h; in 9 of those, average weaning time from mechanical ventilation with propofol was 0.8-4.3 h; with midazolam it was 1.5-7.2 h (weighted mean difference 2.2 h [95% CI, 0.8 to 3.7 h]). In 8 trials, sedation lasted 54 to 339 h; there was a lack of evidence for difference in weaning times. Arterial hypotension (relative risk 2.5 [95% CI, 1.3 to 4.5]; number-needed-to-treat, 12), and hypertriglyceridemia (relative risk 12.1 [95%CI, 2.9 to 49.7]; number-needed-to-treat, 6) occurred more often with propofol. The duration of adequate sedation time is longer with propofol compared with midazolam. In postoperative patients with sedation <36 h, weaning is faster with propofol.

IMPLICATIONS

The duration of adequate sedation time is longer with propofol compared with midazolam. In postoperative patients with sedation < 36 h, weaning is faster with propofol.

Sedation in the intensive care unit

OBJECTIVE

To describe the goals of sedative use in the intensive care unit and review the pharmacology of commonly used sedative drugs as well as to review pertinent publications in the literature concerning the comparative pharmacology of these drugs, with emphasis on outcomes related to sedation and comparative pharmacoeconomics.

DATA SOURCES

Publications in the scientific literature.

DATA EXTRACTION

Computer search of the literature with selection of representative articles.

SYNTHESIS

Proper choice and use of sedative drugs is based on knowledge of the pharmacology of commonly used agents and is an essential component of caring for patients in the intensive care unit. The large variability in pharmacokinetics and pharmacodynamics in the critically ill make it difficult to directly compare agents. Midazolam provides rapid and reliable amnesia, even when administered for low levels of sedation. Propofol may be useful when deeper levels of sedation and more rapid awakening are required. Lorazepam can be used for long-term sedation in more stable patients if rapidity of effect is not required. Further investigation in assessment of depth of sedation in the critically ill is needed. Continued study of costs, side effects, and appropriate dosing strategies of all sedative agents is needed to answer questions not sufficiently addressed in the current literature.

CONCLUSION

An individualized approach to sedation based on knowledge of drug pharmacology is needed because of confounding variables including concurrent patient illness, depth of sedation, and concomitant use of analgesic agents. (Crit Care Med 2000; 28:854-866)

Who goes to the ICU postoperatively?

OBJECTIVE

To describe changes in ICU postoperative management strategies utilized for patients undergoing cardiac surgery. The treatment of these patients serves as a useful illustration of the changing patterns of ICU utilization and care associated with contemporary surgery.

DESIGN

Evidence-based review of the clinical literature following a MEDLINE search, direct observation of rapid recovery programs following surgery, and informal inquiry of others utilizing similar approaches to postoperative cardiac surgery care.

SETTING AND PATIENTS

The reports reviewed are from a diverse set of hospitals providing cardiac surgery services in both Europe and the United States. Most reports focus efforts on patients undergoing coronary artery revascularization.

MEASUREMENTS

Outcome measures used to gauge the effectiveness of postoperative ICU care typically include time to extubation, ICU and hospital length of stay, postoperative complications including reintubation and ICU readmission, patient satisfaction, and health resource savings.

MAIN RESULTS

The literature regarding current practice for postoperative ICU management in cardiac surgery consists primarily of grade 2 and 3 literature.

CONCLUSIONS

Despite the paucity of controlled data, rapid recovery, extubation, and discharge from the ICU following cardiac surgery is an approach to care that is growing in acceptance. The goals include reduction in the utilization of resources and costs associated with cardiac surgery and maintenance of quality of care and patient satisfaction. Assessment of outcomes requires a program to monitor outcomes. Success does not appear to be linked to preoperative risk for most patients but does relate directly to the anesthetic management delivered in the operating room. Few adverse consequences from this approach have been reported. Experience to date suggests that programs designed to truncate ICU admission following cardiac surgery can be implemented with the cooperation between the health delivery team including surgeon, anesthesiologist, intensivist where available, nursing, respiratory care, and patient and family. These programs can serve as useful models for reassessing the utilization and role of the ICU in the postoperative treatment of routine surgical patients.

Complications of sedation with midazolam in the intensive care unit and a comparison with other sedative regimens

OBJECTIVE

To describe the various complications that have been reported with use of midazolam for sedation in the intensive care unit (ICU).

DATA SOURCES

Publications in scientific literature.

DATA EXTRACTION

Computer search of the literature.

SYNTHESIS

Sedation is required in the ICU in order for patients to tolerate noxious stimuli, particularly mechanical ventilation. Under- and oversedation can lead to complications. To sedate patients in the ICU, midazolam is commonly administered via titrated, continuous infusions. Cardiorespiratory effects tend to be minimal; however, hypotension can occur in hypovolemic patients. Prolonged sedation after cessation of the midazolam infusion may be caused by altered kinetics of the drug in critically ill patients or by accumulation of active metabolites. In addition, paradoxical and psychotic reactions have been rarely reported. Tolerance and tachyphylaxis may occur, particularly with longer-term infusions (> or = 3 days). Benzodiazepine withdrawal syndrome has also been associated with high dose/long-term midazolam infusions. Compared with propofol infusions, midazolam infusions have been associated with a decreased occurrence of hypotension but a more variable time course for recovery of function after the cessation of the infusion. Lorazepam is a more cost-effective choice for long-term (> 24 hrs) sedation.

CONCLUSION

Continuous infusion midazolam provides effective sedation in the ICU with few complications overall, especially when the dose is titrated.

Fast-track cardiac surgery: economic implications in postoperative care

Economics is the main driving force in changing health care delivery in the 90s. The motto is to "do more with less." Cost containment and efficient resource utilization swing the pendulum back to the debate of early tracheal extubation in cardiac surgical patients. Recently, it has been confirmed that fast-track cardiac anesthesia is both safe and cost-effective. This article describes the economic implications in postoperative care of fast-track cardiac surgery. First, the developments of early extubation postcardiac surgery and the factors that influence costs of cardiac surgery are reviewed. Second, the morbidity outcome, utilization, and cost implications of early extubation in cardiac surgery are summarized. The perioperative cost analysis in fast-track cardiac surgery, including the cost of complications and resource utilization, is outlined. Lastly, it is important to realize that early extubation does not necessarily mean earlier intensive care unit or hospital discharge. To achieve a maximum cost benefit from early extubation, team organization of a fast-track cardiac surgery program for the perioperative management of these patients is detailed.

Pharmacokinetics and pharmacodynamics of midazolam given via continuous intravenous infusion in intensive care units

Critically ill patients often benefit from sedation to optimize their care and their ventilatory support. Ideally, incremental doses of a drug are administered to produce the desired level of sedation without toxicity or overdose. Because metabolism and elimination of drugs are often altered in critically ill patients, knowledge of the pharmacokinetics of sedative hypnotics is essential to ensure their appropriate selection and administration. Furthermore, the administration of sedatives via continuous infusion minimizes fluctuations in drug concentrations and permits more consistent control of the patient's agitation and anxiety. Physician preference and the patient's individual requirements and underlying diseases are the primary determinants for the selection of a given sedative. Benzodiazepines are the most commonly used sedatives in critical care. Midazolam is readily distinguished from other benzodiazepines because of its rapid onset and short duration of action, low incidence of thrombophlebitis and pain on injection, and minimal cardiovascular and respiratory effects. The physiochemical properties of midazolam allow for enhanced water solubility, which limits physicochemical incompatibilities. These properties make midazolam a valuable sedative that can be given via continuous intravenous infusion in the intensive care unit.

Morbidity outcome in early versus conventional tracheal extubation after coronary artery bypass grafting: a prospective randomized controlled trial

INTRODUCTION

We undertook a prospective, randomized, controlled clinical trial to evaluate morbidity outcomes and safety of a modified anesthetic technique to provide shorter sedation and early extubation (1 to 6 hours) than those of the conventional anesthetic protocol used for prolonged sedation and extubation (12 to 22 hours) in patients after coronary artery bypass grafting.

METHODS

One hundred twenty patients undergoing elective coronary artery bypass grafting were prospectively assigned randomly to either an early extubation group (n = 60; 15 micrograms.kg-1 fentanyl and 2 to 6 mg.kg-1.hour-1 propofol and isoflurane) or to a conventional extubation group (n = 60; 50 micrograms.kg-1 fentanyl and 0.1 mg.kg-1 midazolam and isoflurane). Cardiac morbidity (postoperative myocardial ischemia, postoperative myocardial infarction, and perioperative sympathoadrenal stress response), respiratory morbidity (postextubation apnea, alveolar-arterial oxygen gradient, pulmonary shunting, oxygen consumption, atelectasis, and reintubation), hemodynamic values and vasoactive medication requirements, intraoperative awareness, postoperative cognitive function, 30 day mortality, and intensive care unit and hospital lengths of stay were compared between the two groups.

RESULTS

Fifty-one of the 60 patients in each group (85%) were extubated within the defined time period. Postoperative extubation time and intensive care unit and hospital lengths of stay were significantly shorter in the early group. At 48 hours after operation, there were no significant differences between the two groups in myocardial ischemia incidences, ischemia burdens, or creatine kinase isoenzyme MB levels. Four patients in the conventional group, but not in the early group, had postoperative myocardial infaction. The extubation anesthetics used were effective in suppressing the perioperative plasma catecholamine stress response in both groups. Postextubation apnea characteristics were similar between the groups. Intrapulmonary shunt fraction improved significantly in the early group at 4 hours after extubation. The incidences and degree of atelectasis did not differ significantly between the two groups. The incidences of treated postoperative complications were comparable between the two groups, but three patients in the conventional group died as a result of stroke or postoperative myocardial infarction.

CONCLUSION

Early extubation after coronary artery bypass grafting is safe and does not increase perioperative morbidity. There is an improvement in postextubation intrapulmonary shunt fraction and a reduction in intensive care unit and hospital lengths of stay.

Propofol. An overview of its pharmacology and a review of its clinical efficacy in intensive care sedation

Propofol is a phenolic derivative that is structurally unrelated to other sedative hypnotic agents. It has been used extensively as an anaesthetic agent, particularly in procedures of short duration. More recently it has been investigated as a sedative in the intensive care unit (ICU) where it produces sedation and hypnosis in a dose-dependent manner. Propofol also provides control of stress responses and has anticonvulsant and amnesic properties. Importantly, its pharmacokinetic properties are characterised by a rapid onset and short duration of action. Noncomparative and comparative trials have evaluated the use of propofol for the sedation of mechanically ventilated patients in the ICU (postsurgical, general medical, trauma). Overall, propofol provides satisfactory sedation and is associated with good haemodynamic stability. It produces results similar to or better than those seen with midazolam or other comparator agents when the quality of sedation and/or the amount of time that patients were at adequate levels of sedation are measured. Patients sedated with propofol also tend to have a faster recovery (time to spontaneous ventilation or extubation) than patients sedated with midazolam. Although most studies did not measure time to discharge from the ICU, propofol tended to be superior to midazolam in this respect. In a few small trials in patients with head trauma or following neurosurgery, propofol was associated with adequate sedation and control of cerebral haemodynamics. The rapid recovery of patients after stopping propofol makes it an attractive option in the ICU, particularly for patients requiring only short term sedation. In short term sedation, propofol, despite its generally higher acquisition costs, has the potential to reduce overall medical costs if patients are able to be extubated and discharged from the ICU sooner. Because of the potential for hyperlipidaemia and the development of tolerance to its sedative effects, and because of the reduced need for rapid reversal of drug effects in long term sedation, the usefulness of propofol in long term situations is less well established. While experience with propofol for the sedation of patients in the ICU is extensive, there are still areas requiring further investigation. These include studies in children, trials examining cerebral and haemodynamic outcomes following long term administration and in patients with head trauma and, importantly, pharmacoeconomic investigations to determine those situations where propofol is cost effective. In the meantime, propofol is a well established treatment native to benzodiazepines and/or other hypnotics or analgesics when sedation of patients in the ICU is required. In particular, propofol possesses unique advantages over these agents in patients requiring only short term sedation.

Pro: early extubation after cardiac surgery decreases intensive care unit stay and cost

The recurrent or new trends of early extubation after cardiac surgery are here to stay in the 1990s. The preoperative status does not necessarily predict the postoperative course and prolonged mechanical ventilation following cardiac surgery should not be uncritically considered as routine. All patients should be assessed for tracheal extubation at the earliest opportunity when the criteria are met in the ICU. Early extubation post-cardiac surgery does reduce ICU and hospital length of stay and costs. It also allows early ICU discharge and reduces case cancellations without any increase in postoperative complications and readmission. These studies have emphasized that the change in the process of care to early extubation can affect patient outcome as well as costs in cardiac patient care. The substantial difference in cost savings per cardiac case between "criteria discharge" and "actual discharge" points out the importance of the organization of the process of care being delivered. To achieve maximum cost benefit from early extubation in cardiac patients, the organization of the perioperative management of these patients must be optimized. This process of care includes intraoperative anesthetic modification; organization of ICU and staff expertise; postoperative early extubation and management; acute pain service; ICU discharge policy; utilization of step-down unit and surgical ward; and communication among cardiac patient management teams (cardiovascular surgeon, cardiac anesthesiologist, ICU staff, nurses, respiratory therapists, physiotherapists, and social workers), which are all vital to the success of such a program.

Timing of tracheal extubation in adult cardiac surgery patients

In this article, we examine 14 studies conducted from 1974 to 1994 on "early" endotracheal extubation (0 to 12 hours postoperatively) in adult cardiac surgery patients. Aspects reviewed include: criteria for patient selection; criteria for extubation; analyses of feasibility and safety; effects of anesthetic technique; and patient morbidity. Advantages and disadvantages of early or "fast-track" extubation are discussed as are directions for future research. Selection criteria varied among studies; patients were most commonly excluded because of severe, preexisting pulmonary disease or ventricular dysfunction. Based on the studies examined, however, at least 70% to 80% of adult patients would meet selection criteria. Three universal criteria were applied in all studies: (1) patient is awake and responsive; (2) adequate gas exchange while breathing spontaneously; and (3) cardiovascular stability. To facilitate early extubation in appropriately selected patients, the choice of anesthetic technique and postoperative sedation technique appears to be important. Anesthetic techniques based on inhalational anesthetic agents, supplemented by moderate doses of narcotics, are more appropriate than high-dose narcotic anesthesia for early extubation protocols. Postoperative sedation with propofol, which has a rapid offset of action, may be particularly advantageous. Every published investigation has concluded that early extubation is safe, feasible, and desirable. Morbidity and mortality have not been shown to be affected by early extubation. Anesthetic technique and the patient's medical condition are the two major factors to consider in accomplishing early extubation.

Propofol or midazolam for short-term alterations in sedation

It is often necessary to adjust a patient's sedation level while they are in the intensive care unit. The purpose of this study was to compare propofol with midazolam for controlling short-term alterations in sedation. Twenty-three patients undergoing an interactive procedure, physiotherapy, during mechanical ventilation of the lungs were studied. The patients were randomly assigned to receive infusions of propofol or midazolam for sedation. Sedation was assessed using the method of Ramsay, where 3 is drowsy responding only to commands; and 5 is asleep with a slow response to light glabellar tap. Prior to physiotherapy sedation was deepened from 3 to 5 by increasing the sedative infusion rate, and level 5 was maintained during physiotherapy by adjusting the infusion rate whenever necessary. After physiotherapy, the sedative dose was reduced until level 3 was again achieved. During physiotherapy, sedation level 5 was achieved for 53.9% of the time with propofol but for only 25.7% with midazolam (P < 0.01). After physiotherapy, those patients sedated with propofol re-awakened to level 3 faster (8.3 +/- 2.3 min, mean +/- SE) than those receiving midazolam (92.8 +/- 35.0 min, P < 0.05). After physiotherapy, a further 1.8 +/- 0.5 dose adjustments were required to the midazolam infusion while only 0.4 +/- 0.2 adjustments were required to the propofol infusion (P < 0.05). During physiotherapy 3.0 +/- 0.5 dose adjustments to the propofol dose were required compared with 3.6 +/- 0.5 adjustments to the midazolam dose (NS).(ABSTRACT TRUNCATED AT 250 WORDS)