Pierre Kalfon

Comparison of silver-impregnated with standard multi-lumen central venous catheters in critically ill patients.

Objectives:To evaluate a new silver-impregnated multi-lumen central venous catheter for reducing catheter-related colonization in intensive care patients. Design:Multicenter, prospective, randomized, controlled clinical study. Setting:Ten adult intensive care units (multidisciplinary, medical and surgical, university and nonuniversity hospitals) in eight institutions. Patients:A total of 577 patients who required 617 multi-lumen central venous catheters between November 2002 and April 2004 were studied. Interventions:Intensive care adult patients requiring multi-lumen central venous catheters expected to remain in place for ≥3 days were randomly assigned to undergo insertion of silver-impregnated catheters (silver group) or standard catheters (standard group). Catheter colonization was defined as the growth of ≥1,000 colony-forming units in culture of the intravascular tip of the catheter by the vortexing method. Diagnosis of catheter-related infection was performed by an independent and blinded expert committee. Results:A total of 320 catheters were studied in the silver group and 297 in the standard group. Characteristics of the patients, insertion site, duration of catheterization (median, 11 vs. 10 days), and other risk factors for infection were similar in the two groups. Colonization of the catheter occurred in 47 (14.7%) vs. 36 (12.1%) catheters in the silver and the standard groups (p = .35), for an incidence of 11.2 and 9.4 per 1,000 catheter days, respectively. Catheter-related bloodstream infection was recorded in eight (2.5%) vs. eight (2.7%) catheters in the silver and the standard groups (p = .88), for an incidence of 1.9 and 2.1 per 1,000 catheter days, respectively. Conclusion:The use of silver-impregnated multi-lumen catheters in adult intensive care patients is not associated with a lower rate of colonization than the use of standard multi-lumen catheters.

Permissive Hypercapnia with and without Expiratory Washout in Patients with Severe Acute Respiratory Distress Syndrome

Background: Permissive hypercapnia is a ventilatory strategy aimed at avoiding lung volutrauma in patients with severe acute respiratory distress syndrome (ARDS). Expiratory washout (EWO) is a modality of tracheal gas insufflation that enhances carbon dioxide removal during mechanical ventilation by reducing dead space. The goal of this prospective study was to determine the efficacy of EWO in reducing the partial pressure of carbon dioxide (PaCO2) in patients with severe ARDS treated using permissive hypercapnia. Methods: Seven critically ill patients with severe ARDS (lung injury severity score, 3.1 +/‐ 0.3) and no contraindications for permissive hypercapnia were studied. On the first day, hemodynamic and respiratory parameters were measured and the extent of lung hyperdensities was assessed using computed tomography. A positive end‐expiratory pressure equal to the opening pressure identified on the pressure‐volume curve was applied. Tidal volume was reduced until a plateau airway pressure of 25 cm H2 O was reached. On the second day, after implementation of permissive hypercapnia, EWO was instituted at a flow of 15 l/min administered during the entire expiratory phase into the trachea through the proximal channel of an endotracheal tube using a ventilator equipped with a special flow generator. Cardiorespiratory parameters were studied under three conditions: permissive hypercapnia, permissive hypercapnia with EWO, and permissive hypercapnia. Results: During permissive hypercapnia, EWO decreased PaCO2 from 76 +/‐ 4 mmHg to 53 +/‐ 3 mmHg (‐30%; P < 0.0001), increased pH from 7.20 +/‐ 0.03 to 7.34 +/‐ 0.04 (P < 0.0001), and increased PaO2 from 205 +/‐ 28 to 296 +/‐ 38 mmHg (P < 0.05). The reduction in PaCO sub 2 was accompanied by an increase in end‐inspiratory plateau pressure from 26 +/‐ 1 to 32 +/‐ 2 cm H2 O (P = 0.001). Expiratory washout also decreased cardiac index from 4.6 +/‐ 0.4 to 3.7 +/‐ 0.3 l [center dot] min sup ‐1 [center dot] m sup ‐2 (P < 0.01), mean pulmonary arterial pressure from 28 +/‐ 2 to 25 +/‐ 2 mmHg (P < 0.01), and true pulmonary shunt from 47 +/‐ 2 to 36 +/‐ 3% (P < 0.01). Conclusions: Expiratory washout is an effective and easy‐to‐use ventilatory modality to reduce PaCO2 and increase pH during permissive hypercapnia. However, it significantly increases airway pressures and lung volume through expiratory flow limitation, reexposing some patients to a risk of lung volutrauma if the extrinsic positive end‐expiratory pressure is not substantially reduced.

Glycemic Control in the Intensive Care Unit and during the Postoperative Period

B OTH critical illness and postoperative status are associated with so-called stress-induced hyperglycemia, defined as transient hyperglycemia during illness in patients without previous evidence of diabetes mellitus. The relationship between stress hyperglycemia and poor outcome is largely established for both conditions. In 2001, a large randomized controlled trial (RCT) in critically ill surgical patients demonstrated that tight glucose control (TGC) (defined as the restoration and maintenance of blood glucose concentration BG between 4.4 and 6.1 mM) by intensive insulin therapy (IIT) was associated with a decreased mortality and rate of complications. However, subsequent studies performed in other intensive care units (ICUs) failed to reproduce the beneficial effects of IIT. These conflicting results raise the following clinically relevant question: How can glycemia be controlled in ICUs and during the perioperative period? This commentary summarizes the current understanding of the physiologic regulation of glycemia, the toxicity of hyperglycemia, the mechanisms and consequences of stress hyperglycemia, and the available clinical data from observational and interventional studies. In addition, the unsolved issues and implications for daily clinical practice will be discussed. Updated formal recommendations will be suggested for glucose control in critically ill and postoperative patients.

Determinants of systolic pressure variation in patients ventilated after vascular surgery

OBJECTIVE To discover the predominant determinant of systolic pressure variation during positive-pressure ventilation in mechanically ventilated patients after a vascular surgical procedure. DESIGN Case control study. SETTING Postanesthesia care unit at a university hospital. PARTICIPANTS Eleven patients who were sedated during mechanical ventilation after abdominal aortic surgery. INTERVENTIONS Radial arterial pressure and airway pressure were simultaneously recorded. The systolic pressure variation was measured as the mean difference between the maximal and minimal systolic pressure values during five consecutive mechanical breaths. The delta down was measured as the difference between the systolic blood pressure during apnea and the minimal values of the systolic pressure after one mechanical breath. The velocity time integral, which is closely related to stroke volume, was measured throughout the systolic pressure measurements. MEASUREMENTS AND MAIN RESULTS Positive correlation was found between changes in velocity time integral and the magnitude of both systolic pressure variation (r = 0.73) and delta down (r = 0.80). Volume loading did not significantly modify systolic blood pressure. However, it did not significantly decrease systolic pressure variation and delta down. The corresponding changes in velocity time integral provoked by mechanical ventilation decreased significantly as well. CONCLUSIONS The decrease in systolic pressure provoked by positive-pressure inspiration reflects simultaneous decreases in stroke volume. This suggests that a decrease in left ventricular filling, associated with positive-pressure inspiration, is responsible for systolic pressure variation. This finding confirms the interest in considering systolic pressure variation to provide reliable information about the responsiveness of the heart to preload variations.

Glucose Control in the ICU A Continuing Story

In the present era of near-continuous glucose monitoring (CGM) and automated therapeutic closed-loop systems, measures of accuracy and of quality of glucose control need to be standardized for licensing authorities and to enable comparisons across studies and devices. Adequately powered, good quality, randomized, controlled studies are needed to assess the impact of different CGM devices on the quality of glucose control, workload, and costs. The additional effects of continuing glucose control on the general floor after the ICU stay also need to be investigated. Current algorithms need to be adapted and validated for CGM, including effects on glucose variability and workload. Improved collaboration within the industry needs to be encouraged because no single company produces all the necessary components for an automated closed-loop system. Combining glucose measurement with measurement of other variables in 1 sensor may help make this approach more financially viable.

High-frequency jet ventilation in life-threatening bilateral pulmonary contusion.

TRAUMA is the leading cause of death among young people in developed countries. 1 Because up to 80% of trauma deaths occur during the first 24 h after trauma, 1 early resuscitation and rapid assessment of trauma lesions are of paramount importance to improving the prognosis. Among traumatic lesions, pulmonary contusion is frequent but has not been recognized as an independent prognosis factor. 2-4 In very few cases, pulmonary contusion may lead to severe hypoxia and hypercarbia, which cannot be adequately controlled using conventional mechanical ventilation. Hypoxia and hypercarbia may have deleterious effects, such as enhancement of brain injury and development of circulatory shock. 5 In the most severe cases, aggressive therapeutic methods, such as extracorporeal membrane oxygenation (ECMO), have been reported. 6 At our institution, high-frequency jet ventilation (HFJV) has been used routinely for many years for the treatment of severe acute respiratory distress syndrome. 7,8 We report a series of severe trauma patients with life-threatening pulmonary contusion successfully treated with HFJV when the conventional mechanical ventilation approach failed to provide appropriate gas exchange. The current data suggest that HFJV can be a life-saving technique in severely hypoxemic patients with bilateral pulmonary contusion.

Continuous glucose monitoring in the ICU: clinical considerations and consensus

Glucose management in intensive care unit (ICU) patients has been a matter of debate for almost two decades. Compared to intermittent monitoring systems, continuous glucose monitoring (CGM) can offer benefit in the prevention of severe hyperglycemia and hypoglycemia by enabling insulin infusions to be adjusted more rapidly and potentially more accurately because trends in glucose concentrations can be more readily identified. Increasingly, it is apparent that a single glucose target/range may not be optimal for all patients at all times and, as with many other aspects of critical care patient management, a personalized approach to glucose control may be more appropriate. Here we consider some of the evidence supporting different glucose targets in various groups of patients, focusing on those with and without diabetes and neurological ICU patients. We also discuss some of the reasons why, despite evidence of benefit, CGM devices are still not widely employed in the ICU and propose areas of research needed to help move CGM from the research arena to routine clinical use.

Tight glucose control: should we move from intensive insulin therapy alone to modulation of insulin and nutritional inputs?

The report by Chase and coworkers in the previous issue of Critical Care describes the implementation into clinical practice of the Specialized Relative Insulin Nutrition Table (SPRINT) for tight glycaemic control in critically ill patients. SPRINT is a simple, wheel-based system that modulates both insulin rate and nutritional inputs. It achieved a better glycaemic control in a severely ill critical cohort than their previous method for glycaemic control in a matched historical cohort. Reductions in mortality were also observed.

Subglottic secretion drainage in prevention of ventilator-associated pneumonia: mind the gap between studies and reality

Despite application of preventive measures in bundles, ventilator-associated pneumonia (VAP) remains the most common nosocomial infection, leading to increases in mechanical ventilation duration, ICU stay and healthcare costs [1]. Although two meta-analyses report a half reduction of VAP following use of endotracheal tubes (ETTs) with subglottic secretion drainage (SSD) [2], these devices are not widely employed in clinical practice. Although ETTs with SSD are more expensive, Kelley demonstrates from statistical analyses that these devices could represent health savings [3]. Management of patients intubated before admission to ICU and requiring prolonged mechanical ventilation (≥72 hours) is another concern. This large subgroup is usually excluded from studies evaluating ETTs with SSD even though they may benefit from these devices [4]. In the French IPREA multicenter prospective trial assessing discomforts perceived by 1,380 unselected patients admitted to 14 ICUs between March and November 2005, 869 (63%) patients required intubation and mechanical ventilation. Of these, 541 (62%) were intubated before ICU admission, representing 3,001 (50%) of 5,971 days of mechanical ventilation [5]. This proportion is 48% when only patients requiring 72 h of mechanical ventilation or more are considered. In the IPREA 2 study, of 1,643 patients admitted to 17 French ICUs between March and November 2008 (personal unpublished data), 1,064 (64.8%) were mechanically ventilated. Of the 7,857 days of mechanical ventilation, 54% occurred while the patients were intubated before ICU admission. This proportion is 45% in patients requiring at least 72 hours of mechanical ventilation.

Improving glycemic control in critically ill patients: personalized care to mimic the endocrine pancreas

There is considerable physiological and clinical evidence of harm and increased risk of death associated with dysglycemia in critical care. However, glycemic control (GC) currently leads to increased hypoglycemia, independently associated with a greater risk of death. Indeed, recent evidence suggests GC is difficult to safely and effectively achieve for all patients. In this review, leading experts in the field discuss this evidence and relevant data in diabetology, including the artificial pancreas, and suggest how safe, effective GC can be achieved in critically ill patients in ways seeking to mimic normal islet cell function. The review is structured around the specific clinical hurdles of: understanding the patient’s metabolic state; designing GC to fit clinical practice, safety, efficacy, and workload; and the need for standardized metrics. These aspects are addressed by reviewing relevant recent advances in science and technology. Finally, we provide a set of concise recommendations to advance the safety, quality, consistency, and clinical uptake of GC in critical care. This review thus presents a roadmap toward better, more personalized metabolic care and improved patient outcomes.