Effects of blood pressure lowering in the acute phase of total anterior circulation infarcts and other stroke subtypes

European stroke organisation (ESO) guideline on cerebral small vessel disease, part 2, lacunar ischaemic stroke

A quarter of ischaemic strokes are lacunar subtype, typically neurologically mild, usually resulting from intrinsic cerebral small vessel pathology, with risk factor profiles and outcome rates differing from other stroke subtypes. This European Stroke Organisation (ESO) guideline provides evidence-based recommendations to assist with clinical decisions about management of lacunar ischaemic stroke to prevent adverse clinical outcomes. The guideline was developed according to ESO standard operating procedures and Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. We addressed acute treatment (including progressive lacunar stroke) and secondary prevention in lacunar ischaemic stroke, and prioritised the interventions of thrombolysis, antiplatelet drugs, blood pressure lowering, lipid lowering, lifestyle, and other interventions and their potential effects on the clinical outcomes recurrent stroke, dependency, major adverse cardiovascular events, death, cognitive decline, mobility, gait, or mood disorders. We systematically reviewed the literature, assessed the evidence and where feasible formulated evidence-based recommendations, and expert concensus statements. We found little direct evidence, mostly of low quality. We recommend that patients with suspected acute lacunar ischaemic stroke receive intravenous alteplase, antiplatelet drugs and avoid blood pressure lowering according to current acute ischaemic stroke guidelines. For secondary prevention, we recommend single antiplatelet treatment long-term, blood pressure control, and lipid lowering according to current guidelines. We recommend smoking cessation, regular exercise, other healthy lifestyle modifications, and avoid obesity for general health benefits. We cannot make any recommendation concerning progressive stroke or other drugs. Large randomised controlled trials with clinically important endpoints, including cognitive endpoints, are a priority for lacunar ischaemic stroke.

Adjunctive cytoprotective therapies in acute ischemic stroke: a systematic review

With the introduction of endovascular thrombectomy (EVT), a new era for treatment of acute ischemic stroke (AIS) has arrived. However, despite the much larger recanalization rate as compared to thrombolysis alone, final outcome remains far from ideal. This raises the question if some of the previously tested neuroprotective drugs warrant re-evaluation, since these compounds were all tested in studies where large-vessel recanalization was rarely achieved in the acute phase. This review provides an overview of compounds tested in clinical AIS trials and gives insight into which of these drugs warrant a re-evaluation as an add-on therapy for AIS in the era of EVT. A literature search was performed using the search terms "ischemic stroke brain" in title/abstract, and additional filters. After exclusion of papers using pre-defined selection criteria, a total of 89 trials were eligible for review which reported on 56 unique compounds. Trial compounds were divided into 6 categories based on their perceived mode of action: systemic haemodynamics, excitotoxicity, neuro-inflammation, blood-brain barrier and vasogenic edema, oxidative and nitrosative stress, neurogenesis/-regeneration and -recovery. Main trial outcomes and safety issues are summarized and promising compounds for re-evaluation are highlighted. Looking at group effect, drugs intervening with oxidative and nitrosative stress and neurogenesis/-regeneration and -recovery appear to have a favourable safety profile and show the most promising results regarding efficacy. Finally, possible theories behind individual and group effects are discussed and recommendation for promising treatment strategies are described.

European Stroke Organisation (ESO) guidelines on blood pressure management in acute ischaemic stroke and intracerebral haemorrhage

The optimal blood pressure (BP) management in acute ischaemic stroke (AIS) and acute intracerebral haemorrhage (ICH) remains controversial. These European Stroke Organisation (ESO) guidelines provide evidence-based recommendations to assist physicians in their clinical decisions regarding BP management in acute stroke.The guidelines were developed according to the ESO standard operating procedure and Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. The working group identified relevant clinical questions, performed systematic reviews and meta-analyses of the literature, assessed the quality of the available evidence, and made specific recommendations. Expert consensus statements were provided where insufficient evidence was available to provide recommendations based on the GRADE approach. Despite several large randomised-controlled clinical trials, quality of evidence is generally low due to inconsistent results of the effect of blood pressure lowering in AIS. We recommend early and modest blood pressure control (avoiding blood pressure levels >180/105 mm Hg) in AIS patients undergoing reperfusion therapies. There is more high-quality randomised evidence for BP lowering in acute ICH, where intensive blood pressure lowering is recommended rapidly after hospital presentation with the intent to improve recovery by reducing haematoma expansion. These guidelines provide further recommendations on blood pressure thresholds and for specific patient subgroups. There is ongoing uncertainty regarding the most appropriate blood pressure management in AIS and ICH. Future randomised-controlled clinical trials are needed to inform decision making on thresholds, timing and strategy of blood pressure lowering in different acute stroke patient subgroups.

Renin-angiotensin system as a potential therapeutic target in stroke and retinopathy: experimental and clinical evidence

As our knowledge expands, it is now clear that the renin-angiotensin (Ang) system (RAS) mediates functions other than regulating blood pressure (BP). The RAS plays a central role in the pathophysiology of different neurovascular unit disorders including stroke and retinopathy. Moreover, the beneficial actions of RAS modulation in brain and retina have been documented in experimental research, but not yet exploited clinically. The RAS is a complex system with distinct yet interconnected components. Understanding the different RAS components and their functions under brain and retinal pathological conditions is crucial to reap their benefits. The aim of the present review is to provide an experimental and clinical update on the role of RAS in the pathophysiology and treatment of stroke and retinopathy. Combining the evidence from both these disorders allows a unique opportunity to move both fields forward.

Impact of Comorbidities on Acute Injury and Recovery in Preclinical Stroke Research: Focus on Hypertension and Diabetes

Human ischemic stroke is very complex, and no single preclinical model can comprise all the variables known to contribute to stroke injury and recovery. Hypertension, diabetes, and hyperlipidemia are leading comorbidities in stroke patients. The use of predominantly young adult and healthy animals in experimental stroke research has created a barrier for translation of findings to patients. As such, more and more disease models are being incorporated into the research design. This review highlights the major strengths and weaknesses of the most commonly used animal models of these conditions in preclinical stroke research. The goal is to provide guidance in choosing, reporting, and executing appropriate disease models that will be subjected to different models of stroke injury.

Dynamic interaction of colistin and meropenem on a WT and a resistant strain of Pseudomonas aeruginosa as quantified in a PK/PD model

OBJECTIVES

Combination therapy can be a strategy to ensure effective bacterial killing when treating Pseudomonas aeruginosa, a Gram-negative bacterium with high potential for developing resistance. The aim of this study was to develop a pharmacokinetic/pharmacodynamic (PK/PD) model that describes the in vitro bacterial time-kill curves of colistin and meropenem alone and in combination for one WT and one meropenem-resistant strain of P. aeruginosa.

METHODS

In vitro time-kill curve experiments were conducted with a P. aeruginosa WT (ATCC 27853) (MICs: meropenem 1 mg/L; colistin 1 mg/L) and a meropenem-resistant type (ARU552) (MICs: meropenem 16 mg/L; colistin 1.5 mg/L). PK/PD models characterizing resistance were fitted to the observed bacterial counts in NONMEM. The final model was applied to predict the bacterial killing of ARU552 for different combination dosages of colistin and meropenem.

RESULTS

A model with compartments for growing and resting bacteria, where the bacterial killing by colistin reduced with continued exposure and a small fraction (0.15%) of the start inoculum was resistant to meropenem, characterized the bactericidal effect and resistance development of the two antibiotics. For a typical patient, a loading dose of colistin combined with a high dose of meropenem (2000 mg q8h) was predicted to result in a pronounced kill of the meropenem-resistant strain over 24 h.

CONCLUSIONS

The developed PK/PD model successfully described the time course of bacterial counts following exposures to colistin and meropenem, alone and in combination, for both strains, and identified a dynamic drug interaction. The study illustrates the application of a PK/PD model and supports high-dose combination therapy of colistin and meropenem to overcome meropenem resistance.

Treatment of acute stroke: an update

Stroke is the second leading cause of global mortality after coronary heart disease, and a major cause of neurological disability. About 17 million strokes occur worldwide each year. Patients with stroke often require long-term rehabilitation following the acute phase, with ongoing support from the community and nursing home care. Thus, stroke is a devastating disease and a major economic burden on society. In this overview, we discuss current strategies for specific treatment of stroke in the acute phase, focusing on intravenous thrombolysis and mechanical thrombectomy. We will consider two important issues related to intravenous thrombolysis treatments: (i) how to shorten the delay between stroke onset and treatment and (ii) how to reduce the risk of symptomatic intracerebral haemorrhage. Intravenous thrombolysis has been approved treatment for acute ischaemic stroke in most countries for more than 10 years, with rapid development towards new treatment strategies during that time. Mechanical thrombectomy using a new generation of endovascular tools, stent retrievers, is found to improve functional outcome in combination with pharmacological thrombolysis when indicated. There is an urgent need to increase public awareness of how to recognize a stroke and seek immediate attention from the healthcare system, as well as shorten delays in prehospital and within-hospital settings.

MR perfusion imaging in acute ischemic stroke

Magnetic resonance (MR) perfusion imaging offers the potential for measuring brain perfusion in acute stroke patients, at a time when treatment decisions based on these measurements may affect outcomes dramatically. Rapid advancements in both acute stroke therapy and perfusion imaging techniques have resulted in continuing redefinition of the role that perfusion imaging should play in patient management. This review discusses the basic pathophysiology of acute stroke, the utility of different kinds of perfusion images, and research on the continually evolving role of MR perfusion imaging in acute stroke care.

Management of hypertensive emergencies in acute brain disease: evaluation of the treatment effects of intravenous nicardipine on cerebral oxygenation

Object

Inappropriate sudden blood pressure (BP) reductions may adversely affect cerebral perfusion. This study explores the effect of nicardipine on regional brain tissue O2 (PbtO2) during treatment of acute hypertensive emergencies.

Methods

A prospective case–control study was performed in 30 patients with neurological conditions and clinically elevated BP. All patients had a parenchymal PbtO2 and intracranial pressure bolt inserted following resuscitation. Using a critical care guide, PbtO2 was optimized. Intravenous nicardipine (5–15 mg/hour) was titrated to systolic BP < 160 mm Hg, diastolic BP < 90 mm Hg, mean arterial BP (MABP) 90–110 mm Hg, and PbtO2 > 20 mm Hg. Physiological parameters—intracranial pressure, PbtO2, central venous pressure, systolic BP, diastolic BP, MABP, fraction of inspired O2, and cerebral perfusion pressure (CPP)—were compared before infusion, at 4 hours, and at 8 hours using a t-test.

Results

Sixty episodes of hypertension were reported in 30 patients (traumatic brain injury in 13 patients; aneurysmal subarachnoid hemorrhage in 11; intracerebral and intraventricular hemorrhage in 3 and 1, respectively; arteriovenous malformation in 1; and hypoxic brain injury in 1). Nicardipine was effective in 87% of the patients (with intravenous β blockers in 4 patients), with a 19.7% reduction in mean 4-hour MABP (115.3 ± 13.1 mm Hg preinfusion vs 92.9 ± 11.40 mm Hg after 4 hours of therapy, p < 0.001). No deleterious effect on mean PbtO2 was recorded (26.74 ± 15.42 mm Hg preinfusion vs 27.68 ± 12.51 mm Hg after 4 hours of therapy, p = 0.883) despite significant reduction in CPP. Less dependence on normobaric hyperoxia was achieved at 8 hours (0.72 ± 0.289 mm Hg preinfusion vs 0.626 ± 0.286 mm Hg after 8 hours of therapy, p < 0.01). Subgroup analysis revealed that 12 patients had low pretreatment PbtO2 (10.30 ± 6.49 mm Hg), with higher CPP (p < 0.001) requiring hyperoxia (p = 0.02). In this group, intravenous nicardipine resulted in an 83% improvement in 4- and 8-hour PbtO2 levels (18.1 ± 11.33 and 19.59 ± 23.68 mm Hg, respectively; p < 0.01) despite significant reductions in both mean MABP (120.6 ± 16.65 vs 95.8 ± 8.3 mm Hg, p < 0.001) and CPP (105.00 ± 20.7 vs 81.2 ± 15.4 mm Hg, p < 0.001).

Conclusions

Intravenous nicardipine is effective for the treatment of hypertensive neurological emergencies and has no adverse effect on PbtO2.

Early changes in physiological variables after stroke

Several aspects of physiology, notably blood pressure, body temperature, blood glucose, and blood oxygen saturation, may be altered after an ischemic stroke and intracerebral hemorrhage. Generally, blood pressure and temperature rise acutely after a stroke, before returning to normal. Blood glucose and oxygen levels may be abnormal in individuals, but they do not follow a set pattern. Several aspects of these physiological alterations remain unclear, including their principal determinants - whether they genuinely affect prognosis (as opposed to merely representing underlying processes such as inflammation or a stress response), whether these effects are adaptive or maladaptive, whether the effects are specific to certain subgroups (e.g. lacunar stroke) and whether modifying physiology also modifies its prognostic effect. Hypertension and hyperglycemia may be helpful or harmful, depending on the perfusion status after an ischemic stroke; the therapeutic response to their lowering may be correspondingly variable. Hypothermia may provide benefits, in addition to preventing harm through protection from hyperthermia. Hypoxia is harmful, but normobaric hyperoxia is unhelpful or even harmful in normoxic patients. Hyperbaric hyperoxia, however, may be beneficial, though this remains unproven. The above-mentioned uncertainties necessitate generally conservative measures for physiology management, although there are notably specific recommendations for thrombolysis-eligible patients. Stroke unit care is associated with better outcome, possibly through better management of poststroke physiology. Stroke units can also facilitate research to clarify the relationship between physiology and prognosis, and to subsequently clarify management guidelines.

Transient ischemic attack: risk stratification and treatment

A major challenge facing the physician evaluating patients with transient ischemic attack is determining which patients are at highest short-term risk of stroke. A number of stratification schemes have been recently developed incorporating easily obtainable clinical information about the individual patient. Further, emerging data suggest a role for brain and vascular imaging in risk stratification. Many aspects of acute management of transient ischemic attack, such as which patients should be hospitalized and choice of acute antithrombotic therapy, remain controversial because of a lack of evidence from controlled trials. For longer-term prevention, there is much firmer evidence from multiple large randomized trials, and these data are reviewed in this article.

The time course and determinants of blood pressure within the first 48 h after ischemic stroke

BACKGROUND AND PURPOSE

Previous research suggests that blood pressure falls acutely after ischemic stroke. We aimed to further characterize this fall with a statistical technique that allows the application of regression techniques to serial blood pressure outcome data.

METHODS

In a prospectively recruited ischemic stroke cohort, systolic (SBP) and diastolic (DBP) blood pressure was recorded every 4 h until 48 h after stroke. Potential determinants of blood pressure, including stroke severity and acute infection, were also recorded. Mixed effects models were used to model serial blood pressure measurements over time, adjusted for significant determinants.

RESULTS

In 156 patients, SBP and DBP fell by 14.9 mm Hg (95% CI 6.2-22.6 mm Hg) and 6.2 mm Hg (95% CI 1.4-10.6 mm Hg), respectively, over the first 48 h after stroke. SBP was higher in patients with premorbid hypertension, a previous history of stroke or TIA, current alcohol use, increasing age, stroke of mild to moderate severity (NIHSS 3-13) and in patients treated with antihypertensives. SBP was lower in smokers. There was a progressive rise in SBP in patients with acute infection. No factors other than time were associated with DBP.

CONCLUSIONS

The use of mixed effects models has identified a linear SBP and DBP fall over the first 48 h after stroke. The timing and magnitude of this fall should be accounted for in the design of future prognostic and intervention studies.

Guidelines for the Early Management of Adults With Ischemic Stroke

Purpose— Our goal is to provide an overview of the current evidence about components of the evaluation and treatment of adults with acute ischemic stroke. The intended audience is physicians and other emergency healthcare providers who treat patients within the first 48 hours after stroke. In addition, information for healthcare policy makers is included.

Methods— Members of the panel were appointed by the American Heart Association Stroke Council’s Scientific Statement Oversight Committee and represented different areas of expertise. The panel reviewed the relevant literature with an emphasis on reports published since 2003 and used the American Heart Association Stroke Council’s Levels of Evidence grading algorithm to rate the evidence and to make recommendations. After approval of the statement by the panel, it underwent peer review and approval by the American Heart Association Science Advisory and Coordinating Committee. It is intended that this guideline be fully updated in 3 years.

Results— Management of patients with acute ischemic stroke remains multifaceted and includes several aspects of care that have not been tested in clinical trials. This statement includes recommendations for management from the first contact by emergency medical services personnel through initial admission to the hospital. Intravenous administration of recombinant tissue plasminogen activator remains the most beneficial proven intervention for emergency treatment of stroke. Several interventions, including intra-arterial administration of thrombolytic agents and mechanical interventions, show promise. Because many of the recommendations are based on limited data, additional research on treatment of acute ischemic stroke is needed.

Guidelines for the early management of adults with ischemic stroke: a guideline from the American Heart Association/American Stroke Association Stroke Council, Clinical Cardiology Council, Cardiovascular Radiology and Intervention Council, and the Atherosclerotic Peripheral Vascular Disease and Quality of Care Outcomes in Research Interdisciplinary Working Groups: the American Academy of Neurology affirms the value of this guideline as an educational tool for neurologists

PURPOSE

Our goal is to provide an overview of the current evidence about components of the evaluation and treatment of adults with acute ischemic stroke. The intended audience is physicians and other emergency healthcare providers who treat patients within the first 48 hours after stroke. In addition, information for healthcare policy makers is included.

METHODS

Members of the panel were appointed by the American Heart Association Stroke Council's Scientific Statement Oversight Committee and represented different areas of expertise. The panel reviewed the relevant literature with an emphasis on reports published since 2003 and used the American Heart Association Stroke Council's Levels of Evidence grading algorithm to rate the evidence and to make recommendations. After approval of the statement by the panel, it underwent peer review and approval by the American Heart Association Science Advisory and Coordinating Committee. It is intended that this guideline be fully updated in 3 years.

RESULTS

Management of patients with acute ischemic stroke remains multifaceted and includes several aspects of care that have not been tested in clinical trials. This statement includes recommendations for management from the first contact by emergency medical services personnel through initial admission to the hospital. Intravenous administration of recombinant tissue plasminogen activator remains the most beneficial proven intervention for emergency treatment of stroke. Several interventions, including intra-arterial administration of thrombolytic agents and mechanical interventions, show promise. Because many of the recommendations are based on limited data, additional research on treatment of acute ischemic stroke is needed.

The challenge of blood pressure management in neurologic emergencies

Hypertensive crises are commonly seen in the emergency department, and acute stroke is often the inciting etiology of a hypertensive crisis. Cerebral autoregulation is disrupted in acute stroke, and efforts to lower blood pressure may reduce cerebral perfusion and worsen outcomes. Although most patients with stroke have elevated blood pressure, evidence from clinical trials to guide therapy are scarce. Current national guidelines recommend lowering blood pressure after stroke only if end-organ damage is present or if systolic/diastolic blood pressures exceed 220/120 or 185/110 mm Hg in patients ineligible and in those eligible to receive thrombolytic drug therapy, respectively. Recommended pharmacologic interventions for elevated blood pressure after acute ischemic stroke include labetalol, nicardipine, or nitroprusside, depending on the severity of the elevation. Similar recommendations have been made for intracerebral hemorrhage. Subarachnoid hemorrhage is managed with nimodipine and other calcium channel blockers to prevent vasospasm and improve clinical outcomes. Data from ongoing clinical trials may improve guidance about the management of elevated blood pressure after acute stroke.

Systemic inflammation, blood pressure, and stroke outcome

Hypertension is the most important modifiable risk factor for ischemic stroke, and antihypertensive treatment is of paramount importance to reduce the incidence of stroke mortality and morbidity. The significance and best management of hypertension during the first hours after stroke onset, however, are still matters of debate. Cerebral ischemia results in a complex inflammatory cascade; inflammatory mechanisms are also important participants in the pathophysiology of hypertension. There has been a convergence of evidence that is important to consider in managing systemic blood pressure after stroke to ensure an optimal outcome. The identification of useful markers will allow progress in our ability to treat blood pressure in the acute phase of a stroke. The determination of levels of C-reactive protein, an acute-phase inflammation marker, may help to guide our approach in the management of blood pressure in acute ischemic stroke. Whether this target will be useful in the development of risk prediction strategies or therapies for the treatment of stroke in humans is far from clear.

Systemic blood pressure and stroke outcome and recurrence

Although it is clear that hypertension is a primary cause of stroke, there has been controversy concerning blood pressure management after stroke. Recent studies indicate that lowering systemic blood pressure after stroke reduces the risk for recurrent stroke or vascular events, but other studies provide evidence that blood pressure should not be lowered in the first week after stroke onset. Additional investigations have provided preliminary evidence that raising blood pressure in the first few days after stroke may improve outcome in selected patients. However, other studies have recorded the benefit of lowering blood pressure in some patients at the acute stage, whereas still others have identified patients in whom lowering blood pressure even later after stroke may be more harmful than beneficial. The remaining challenge is to identify efficient measures for determining when to lower blood pressure in each case of ischemic stroke.

What do we (not) know about the management of blood pressure in acute stroke?

Although it is indisputable that high blood pressure should be treated to prevent a first or a recurrent stroke, the management of high blood pressure in the first hours and days after stroke remains controversial. There is no high-quality evidence from randomized controlled trials to guide treatment in the 80% of patients who have elevated blood pressure during the first days after stroke. Theoretically, there are pros and cons for manipulating blood pressure after onset of stroke. Most treatment guidelines suggest leaving blood pressure untouched based on pathophysiologic principles. Post-hoc analyses from randomized trials, however, suggest that elevated blood pressure is associated with recurrent stroke and higher mortality, even after adjustment for potential confounders. On the other hand, preliminary studies have suggested that voluntarily increasing blood pressure might be beneficial in a selected subgroup of patients. In this overview, we present a summary of recent studies on this topic.

Salivary cortisol, a biological marker of stress, is positively associated with 24-hour systolic blood pressure in patients with acute ischaemic stroke

BACKGROUND/AIM

The cause of elevated blood pressure (BP) in acute stroke is unknown. Stress is often suggested as a main contributing factor. We aimed to investigate the relationship between BP and stress in patients with acute stroke.

METHODS

58 patients with clinical symptoms of stroke were recruited prospectively after exclusion of haemorrhage by CT scan within 14 h and 15 min (mean) after symptom onset (range 2 h and 45 min-23 h and 40 min). The mean age of the patients was 66 years (range 39-86 years), and the mean National Institute of Health Stroke Scale score was 7 (range 1-26). BP and pulse rate were recorded by non-invasive automatic monitoring hourly for 24 h. Stress was evaluated by testing the level of salivary cortisol. Four samples of saliva were obtained at inclusion, on the evening of the inclusion day (20.00-22.00 h), on the morning of the next day (7.00-9.00 h) and on the afternoon of the inclusion day/next day (15.00-17.00 h) within 24 h after inclusion in the study. Logarithmic transformation was done for cortisol levels.

RESULTS

The 24-hour mean cortisol level (geometric mean 13.6 nmol/l) was related to 24-hour mean systolic BP [SBP; r = 0.36, p = 0.01, multivariate p = 0.02], mean night-time (22.00-6.00 h) SBP (r = 0.43, p = 0.001, multivariate p < 0.005) and mean night-time diastolic BP (r = 0.31, p = 0.02, multivariate p = 0.02). Cortisol levels at inclusion (r = 0.31, p = 0.02, multivariate p = 0.05 for 24-hour SBP) and in the evening were also statistically significantly related to the above BP variables. The morning cortisol (r = 0.28, p = 0.04, multivariate p = 0.04) was related to night-time SBP.

CONCLUSIONS

Salivary cortisol was positively correlated with 24-hour SBP and night-time BP, suggesting that stress is a contributing factor for high BP in acute stroke.

Systemic blood pressure and stroke outcome and recurrence

Although it is clear that hypertension is a primary cause of stroke, there has been recent controversy about blood pressure management after stroke. Recent studies indicate that lowering systemic blood pressure after stroke does reduce the risk of recurrent stroke or vascular events, but other studies provide evidence that blood pressure should not be lowered in the first week after stroke onset. Additional investigations have provided preliminary evidence that raising blood pressure in the first few days after stroke may improve outcome in selective patients. However, other studies have recorded benefit of lowering blood pressure in some patients at the acute stage, whereas still others have identified patients in whom lowering blood pressure even later after stroke may be more harmful than beneficial. The remaining challenge is to identify efficient measures for determining when to lower blood pressure in each case of ischemic stroke.

Use of parenteral colistin for the treatment of serious infection due to antimicrobial-resistant Pseudomonas aeruginosa

Serious infection due to strains of Pseudomonas aeruginosa that exhibit resistance to all common antipseudomonal antimicrobials increasingly is a serious problem. Colistin was used as salvage therapy for 23 critically ill patients with multidrug-resistant P. aeruginosa infection. Twenty-two patients who had septic shock (n=14) and/or renal failure (n=21) received mechanical ventilatory support at baseline. The most common types of infection were pneumonia (n=18) and intra-abdominal infection (n=5). Colistin was administered for a median of 17 days (range, 7-36 days). Seven patients died during therapy, at a median of 17 days (range, 4-26 days) after initiation of treatment. A favorable clinical response was observed in 14 patients (61%); only 3 patients experienced relapse. Bacteremia was the only significant factor associated with treatment failure (P=.02). One patient manifested diffuse weakness that resolved after temporary cessation of colistin therapy. Colistin provides an important salvage therapeutic option for patients with otherwise untreatable serious P. aeruginosa infection.