The use of static and dynamic haemodynamic parameters before volume expansion: A prospective observational study in six French intensive care units

OBJECTIVE

The aim of the present study was to determine the use of static and dynamic haemodynamic parameters for predicting fluid responsiveness prior to volume expansion (VE) in intensive care unit (ICU) patients with systemic inflammatory response syndrome (SIRS).

METHODS

We conducted a prospective, multicentre, observational study in 6 French ICUs in 2012. ICU physicians were audited concerning their use of static and dynamic haemodynamic parameters before each VE performed in patients with SIRS for 6 consecutive weeks.

RESULTS

The median volume of the 566 VEs administered to patients with SIRS was 1000mL [500-1000mL]. Although at least one static or dynamic haemodynamic parameter was measurable before 99% (95% CI, 99%-100%) of VEs, at least one them was used in only 38% (95% CI, 34%-42%) of cases: static parameters in 11% of cases (95% CI, 10%-12%) and dynamic parameters in 32% (95% CI, 30%-34%). Static parameters were never used when uninterpretable. For 15% of VEs (95% CI, 12%-18%), a dynamic parameter was measured in the presence of contraindications. Among dynamic parameters, respiratory variations in arterial pulse pressure (PPV) and passive leg raising (PLR) were measurable and interpretable before 17% and 90% of VEs, respectively.

CONCLUSIONS

Haemodynamic parameters are underused for predicting fluid responsiveness in current practice. In contrast to static parameters, dynamic parameters are often incorrectly used in the presence of contraindications. PLR is more frequently valid than PPV for predicting fluid responsiveness in ICU patients.

Gentle blood aspiration and tube cushioning reduce pneumatic tube system interference in lactate dehydrogenase assays

Background

Use of a hospital pneumatic tube system may be associated with measurement errors.

Methods

A venous blood sample was collected from 79 patients into a pair of lithium heparin tubes; one tube was sent to the laboratory by porter and the other was sent via the pneumatic tube system. Plasma lactate dehydrogenase concentrations were then assayed.

Results

Lactate dehydrogenase concentrations were overestimated (median bias: 18.8%) when evacuated vacuum lithium heparin tubes were sent by pneumatic tube system. This bias was reduced by bubble-wrapping the standard lithium heparin tube or using Monovette lithium heparin tubes in aspiration mode (median bias: +8.7% and −0.3%, respectively).

Conclusions

Cushioning and aspiration-mode sampling may limit pneumatic tube system-associated overestimation of lactate dehydrogenase concentrations.

Efficiency of a pneumatic device in controlling cuff pressure of polyurethane-cuffed tracheal tubes: a randomized controlled study

Background

The primary objective of this study was to determine the efficiency of a pneumatic device in controlling cuff pressure (P_cuff) in patients intubated with polyurethane-cuffed tracheal tubes. Secondary objectives were to determine the impact of continuous control of P_cuff, and cuff shape on microaspiration of gastric contents.

Methods

Prospective randomized controlled study. All patients requiring intubation and mechanical ventilation ≥48 h were eligible. The first 32 patients were intubated with tapered polyurethane-cuffed, and the 32 following patients were intubated with cylindrical polyurethane-cuffed tracheal tubes. Patients randomly received 24 h of continuous control of P_cuff using a pneumatic device (Nosten®), and 24 h of routine care of P_cuff using a manometer. Target P_cuff was 25 cmH₂O. P_cuff was continuously recorded, and pepsin was quantitatively measured in all tracheal aspirates during these periods.

Results

The pneumatic device was efficient in controlling P_cuff (med [IQ] 26 [24, 28] vs 22 [20, 28] cmH₂O, during continuous control of P_cuff and routine care, respectively; p = 0.017). In addition, percentage of patients with underinflation (31% vs 68%) or overinflation (53% vs 100%) of tracheal cuff, and percentage of time spent with underinflation (0.9 [0, 17] vs 14% [4, 30]) or overinflation (0 [0, 2] vs 32% [9, 54]) were significantly (p < 0.001) reduced during continuous control of P_cuff compared with routine care.

No significant difference was found in microaspiration of gastric content between continuous control of P_cuff compared with routine care, or between patients intubated with tapered compared with cylindrical polyurethane-cuffed tracheal tubes.

Conclusion

The pneumatic device was efficient in controlling P_cuff in critically ill patients intubated with polyurethane-cuffed tracheal tubes.

Trial registration

The Australian New Zealand Clinical Trials Registry (NCT01351259)

Adverse events during intrahospital transport of critically ill patients: incidence and risk factors

Background

Transport of critically ill patients for diagnostic or therapeutic procedures is at risk of complications. Adverse events during transport are common and may have significant consequences for the patient. The objective of the study was to collect prospectively adverse events that occurred during intrahospital transports of critically ill patients and to determine their risk factors.

Methods

This prospective, observational study of intrahospital transport of consecutively admitted patients with mechanical ventilation was conducted in a 38-bed intensive care unit in a university hospital from May 2009 to March 2010.

Results

Of 262 transports observed (184 patients), 120 (45.8%) were associated with adverse events. Risk factors were ventilation with positive end-expiratory pressure >6 cmH₂O, sedation before transport, and fluid loading for intrahospital transports. Within these intrahospital transports with adverse events, 68 (26% of all intrahospital transports) were associated with an adverse event affecting the patient. Identified risk factors were: positive end-expiratory pressure >6 cmH₂O, and treatment modification before transport. In 44 cases (16.8% of all intrahospital transports), adverse event was considered serious for the patient. In our study, adverse events did not statistically increase ventilator-associated pneumonia, time spent on mechanical ventilation, or length of stay in the intensive care unit.

Conclusions

This study confirms that the intrahospital transports of critically ill patients leads to a significant number of adverse events. Although in our study adverse events have not had major consequences on the patient stay, efforts should be made to decrease their incidence.

New methods to clean ICU rooms

Hospital-acquired infections (HAI) represent the most common adverse event in the intensive care unit (ICU). Their prevalence is high and they are associated with increased morbidity and mortality. The environment plays a central role in the transmission of hospital-acquired pathogens (HAP) and in the pathogenesis of HAI. Many bacteria, especially multidrug resistant ones, can survive for several months in the hospital environment in particular in areas close to the patients. It has been proven that pathogens are transmitted from the environment to the patients. Many studies have concluded that current cleaning methods are microbiologically ineffective. This failure concerns daily cleaning as well as terminal cleaning after patient discharge. It has been demonstrated that improvements in environmental cleaning are associated with a decrease in the rate of HAP and of HAI. New cleaning methods could enhance hospital cleaning efficiency. Three new technologies seem promising because they are microbiologically effective, easy and safe to use: (1) hydrogen peroxide vapor and (2) UV light decontamination are used for terminal cleaning. These techniques are effective even in difficultly accessible areas. (3) ultramicrofibers which can be associated with a copper-based biocide can be used for daily cleaning. Other methods such as ozone, steam or high-efficiency particulate air filtration are not efficient enough to be considered serious contenders for the improvement of the quality of the hospital environment. These new technologies have not been yet linked to a decrease in the prevalence and the incidence in HAP and HAI. It remains difficult to justify the extra-cost associated with these new methods until more studies can confirm their effectiveness in the management of HAI.

The impact of COPD on ICU mortality in patients with ventilator-associated pneumonia

OBJECTIVE

To determine the impact of COPD on intensive care unit (ICU) mortality in patients with VAP.

METHODS

This prospective observational study was performed in a mixed ICU during a 3-year period. Eligible patients received mechanical ventilation for >48 h and met criteria for microbiologically confirmed VAP. Risk factors for ICU mortality were determined using univariate and multivariable analyses.

RESULTS

Two hundred and fifteen patients with microbiologically confirmed VAP were included. Most VAP episodes were late-onset (88%), and Pseudomonas aeruginosa was the most frequently isolated bacterium (39% of VAP episodes). ICU mortality was significantly lower in non-COPD patients (n = 150) compared to COPD patients (n = 65) (43.3% vs 60%, p = 0.027, OR [95% CI] = 1.96 [1.8-3.54]). Duration (days) of mechanical ventilation and ICU stay median (IQR) in non-COPD patients were 25 (15-42) and 30 (18-48), whereas in COPD patients were 31 (19-45) and 36 (20-48) (p > 0.05). The differences in duration (days) of mechanical ventilation and ICU stay were significant between non-COPD patients and severe COPD (GOLD stage IV) patients (p = 0.001 and p = 0.02, respectively). Multivariable analysis identified COPD [OR (95% CI) 2.58 (1.337-5)], SAPS II [1.024 (1.006-1.024)] and presence of shock at VAP diagnosis [3.72 (1.88-7.39)] as independent risk factors for ICU mortality.

CONCLUSION

COPD, SAPS II, and shock at VAP diagnosis are independently associated with ICU mortality in patients who present VAP.

Risk of acquiring multidrug-resistant Gram-negative bacilli from prior room occupants in the intensive care unit

The objective of this prospective cohort study was to determine whether admission to an intensive care unit (ICU) room previously occupied by a patient with multidrug-resistant (MDR) Gram-negative bacilli (GNB) increases the risk of acquiring these bacteria by subsequent patients. All patients hospitalized for >48 h were eligible. Patients with MDR GNB at ICU admission were excluded. The MDR GNB were defined as MDR Pseudomonas aeruginosa, Acinetobacter baumannii and extended spectrum β-lactamase (ESBL) -producing GNB. All patients were hospitalized in single rooms. Cleaning of ICU rooms between two patients was performed using quaternary ammonium disinfectant. Risk factors for MDR P. aeruginosa, A. baumannii and ESBL-producing GNB were determined using univariate and multivariate analysis. Five hundred and eleven consecutive patients were included; ICU-acquired MDR P. aeruginosa was diagnosed in 82 (16%) patients, A. baumannii in 57 (11%) patients, and ESBL-producing GNB in 50 (9%) patients. Independent risk factors for ICU-acquired MDR P. aeruginosa were prior occupant with MDR P. aeruginosa (OR 2.3, 95% CI 1.2-4.3, p 0.012), surgery (OR 1.9, 95% CI 1.1-3.6, p 0.024), and prior piperacillin/tazobactam use (OR 1.2, 95% CI 1.1-1.3, p 0.040). Independent risk factors for ICU-acquired A. baumannii were prior occupant with A. baumannii (OR 4.2, 95% CI 2-8.8, p <0.001), and mechanical ventilation (OR 9.3, 95% CI 1.1-83, p 0.045). Independent risk factors for ICU-acquired ESBL-producing GNB were tracheostomy (OR 2.6, 95% CI 1.1-6.5, p 0.049), and sedation (OR 6.6, 95% CI 1.1-40, p 0.041). We conclude that admission to an ICU room previously occupied by a patient with MDR P. aeruginosa or A. baumannii is an independent risk factor for acquisition of these bacteria by subsequent room occupants. This relationship was not identified for ESBL-producing GNB.

Intensive Care Unit-acquired infection as a side effect of sedation

Introduction

Sedative and analgesic medications are routinely used in mechanically ventilated patients. The aim of this review is to discus epidemiologic data that suggest a relationship between infection and sedation, to review available data for the potential causes and pathophysiology of this relationship, and to identify potential preventive measures.

Methods

Data for this review were identified through searches of PubMed, and from bibliographies of relevant articles.

Results

Several epidemiologic studies suggested a link between sedation and ICU-acquired infection. Prolongation of exposure to risk factors for infection, microaspiration, gastrointestinal motility disturbances, microcirculatory effects are main mechanisms by which sedation may favour infection in critically ill patients. Furthermore, experimental evidence coming from studies both in humans and animals suggest that sedatives and analgesics present immunomodulatory properties that might alter the immunologic response to exogenous stimuli. Clinical studies comparing different sedative agents do not provide evidence to recommend the use of a particular agent to reduce ICU-acquired infection rate. However, sedation strategies aiming to reduce the duration of mechanical ventilation, such as daily interruption of sedatives or nursing-implementing sedation protocol, should be promoted. In addition, the use of short acting opioids, propofol, and dexmedetomidine is associated with shorter duration of mechanical ventilation and ICU stay, and might be helpful in reducing ICU-acquired infection rates.

Conclusions

Prolongation of exposure to risk factors for infection, microaspiration, gastrointestinal motility disturbances, microcirculatory effects, and immunomodulatory effects are main mechanisms by which sedation may favour infection in critically ill patients. Future studies should compare the effect of different sedative agents, and the impact of progressive opioid discontinuation compared with abrupt discontinuation on ICU-acquired infection rates.

Daily serum piperacillin monitoring is advisable in critically ill patients

The aim of the present study was to evaluate the benefit of monitoring serum piperacillin concentrations in critically ill patients. This was an 11-month, prospective, observational study in a 30-bed Intensive Care Unit in a teaching hospital, involving 24 critically ill patients with evidence of bacterial sepsis. All patients received a 66 mg/kg intravenous bolus of piperacillin in combination with tazobactam (ratio 1:0.125) followed by continuous infusion of 200mg/kg/24h. The dosage was adjusted when the serum piperacillin concentration either fell below 4x the drug's minimum inhibitory concentration (MIC) for the causative agent or exceeded the toxic threshold of 150 mg/L. With the initial regimen, serum piperacillin concentrations were within the therapeutic target range in only 50.0% of patients (n=12). This proportion increased to 75.0% (18 patients) (P=0.006) following dosage adjustment. For patients with low initial serum piperacillin concentrations (n=8), the percentage of time during which the concentration remained above 4x MIC (%T>4x MIC) was 7.1+/-5.9% before dosage adjustment and 27.3+/-8.6% afterwards. In conclusion, in critically ill patients, monitoring and adjustment of serum piperacillin levels is required to prevent overdosing and might also help to correct underdosing, an important cause of antibiotic therapy failure.

[An alternative method to describe an "obesogenic" environment for children: Relevance of a multiple correspondence analysis (MCA) (corrected)]

The purpose of this study was to describe an "obesogenic" environment for a group of schoolchildren using a multiple correspondence analysis (MCA) as an alternative approach to traditional methodological choices. MCA is applicable even for small samples. Ninety-one children (39 girls and 52 boys) aged 10.0 +/- 0.9 years were randomly recruited from two French public schools. Data on their family context, parental involvement, television time and their eating habits were obtained through questionnaires. Their level of physical activity and sedentary time were assessed using an accelerometer (MTI Actigraph model 7164) for three days, including a holiday. The data were processed using an MCA together with a technique for estimating relative risks (RRs) of overweight/obesity according to the distribution of children in the factorial plane produced by the MCA. The "obesogenic" factors appeared as four possible combinations between family environments and various behaviours with regard to physical activity, sedentary behaviour and diet. The RR of overweight/obesity was 2.64 [1.52, 4.57] (P < 0.0001) for a combined association of a "disadvantaged" family environment + low physical activity and high fat diet. The RR of overweight/obesity was 0.36 [0.14, 0.94] (P < 0.05) for an association of a "privileged" family environment + high physical activity and low fat diet. Thus, MCA appears sufficiently robust and relevant to effectively guide etiological hypotheses and decisions about individual and collective intervention strategies.

Remifentanil discontinuation and subsequent intensive care unit-acquired infection: a cohort study

INTRODUCTION

Recent animal studies demonstrated immunosuppressive effects of opioid withdrawal resulting in a higher risk of infection. The aim of this study was to determine the impact of remifentanil discontinuation on intensive care unit (ICU)-acquired infection.

METHODS

This was a prospective observational cohort study performed in a 30-bed medical and surgical university ICU, during a one-year period. All patients hospitalised in the ICU for more than 48 hours were eligible. Sedation was based on a written protocol including remifentanil with or without midazolam. Ramsay score was used to evaluate consciousness. The bedside nurse adjusted sedative infusion to obtain the target Ramsay score. Univariate and multivariate analyses were performed to determine risk factors for ICU-acquired infection.

RESULTS

Five hundred and eighty-seven consecutive patients were included in the study. A microbiologically confirmed ICU-acquired infection was diagnosed in 233 (39%) patients. Incidence rate of ICU-acquired infection was 38 per 1000 ICU-days. Ventilator-associated pneumonia was the most frequently diagnosed ICU-acquired infection (23% of study patients). Pseudomonas aeruginosa was the most frequently isolated microorganism (30%). Multivariate analysis identified remifentanil discontinuation (odds ratio (OR) = 2.53, 95% confidence interval (CI) = 1.28 to 4.99, P = 0.007), simplified acute physiology score II at ICU admission (1.01 per point, 95% CI = 1 to 1.03, P = 0.011), mechanical ventilation (4.49, 95% CI = 1.52 to 13.2, P = 0.006), tracheostomy (2.25, 95% CI = 1.13 to 4.48, P = 0.021), central venous catheter (2.9, 95% CI = 1.08 to 7.74, P = 0.033) and length of hospital stay (1.05 per day, 95% CI = 1.03 to 1.08, P < 0.001) as independent risk factors for ICU-acquired infection.

CONCLUSIONS

Remifentanil discontinuation is independently associated with ICU-acquired infection.

Actigraph-defined moderate-to-vigorous physical activity cut-off points among children: statistical and biobehavioural relevance

AIM

To compare Actigraph-defined moderate-to-vigorous physical activity (MVPA) cutpoints among children, combining statistical and biobehavioural analyses.

METHODS

One hundred and thirteen children aged 10.0 +/- 0.8 years wore accelerometer for three days. The time they spent in MVPA was estimated using 10 thresholds ranged from 3000 to 3900 cpm. A statistical construct including 45 Bland and Altman pairwise analyses was used to compare the 10 estimates of MVPA. A regression was performed to develop an equation relating mean differences to the between-cutpoint gaps.

RESULTS

Mean differences in the MVPA estimates ranged from 1.6 to 12.8 min as a function of increment. Raw estimates of MVPA decreased according to an arithmetic sequence with a common difference of 200 cpm. This difference translates into a drop of 12% in MVPA and a misclassification of up to 5% of children. Mean differences (Y) could be predicted from increments (X) using: Y= 0.02 X (R(2)= 0.99, SEE = 0.72, p < 0.0001).

CONCLUSION

When a lack of agreement should be assumed as the between-cutpoint gap exceeds 200 cpm, statistical differences may occur earlier at 90 cpm. Yet, the current equation makes it possible to compare and adjust results from studies/interventions using diverse cutpoints for MVPA among children.

Prehospital pain treatment: an economic productivity factor in emergency medicine?

RATIONALE AND OBJECTIVES

Analgesia is a recommended practice for pain treatment in prehospital emergency medicine, but all experts note suboptimal pain relief or oligoanalgesia. The increase in the Care Workload (CW) and the Medical Treatment Duration (MTD) linked to analgesia are two explanatory factors, and they are representative of the unavailability of a prehospital team. The unavailability of a team is an opportunity cost which is probably the most important cost within the framework of prehospital emergency. The aim of this study was to analyse the influence of analgesia use on the availability of prehospital emergency teams.

METHODS

This study was a prospective, multicentre cohort study conducted in 10 French Mobile Emergency and Resuscitation Services (MERS) between September 2001 and June 2003. A case-control study was performed including 568 case patients who received analgesia matched with controls based on diagnosis and severity. The pairs were compared for MTD and CW.

RESULTS

No significant difference between cases and controls was found concerning MTD (P = 0.134). Conversely, a difference was found for CW (P < 10(-4)), with a mean value of 53.7 Project Recherche Nursing (PRN) points for the cases and 45.8 PRN points for the controls.

CONCLUSIONS

This study shows that analgesia generates an additional CW without increasing the MTD, and does not hinder the MERS teams' availability. This economic result should improve adherence to these clinical practice guidelines. Thus, analgesia appears to be a factor of productivity in the current context of economic pressures in terms of the funding of the healthcare system.

Factors predicting bacterial involvement in severe acute exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Strategies aiming at reducing antibiotic use are required in the intensive care unit (ICU). Although antibiotic treatment is recommended in patients with severe exacerbation of chronic obstructive pulmonary disease (COPD), a bacterial etiology is found in only a half of these patients.

OBJECTIVES

The aim of this study was to determine factors predicting bacterial isolation in severe acute exacerbations of COPD.

METHODS

All patients with severe acute exacerbation of COPD requiring intubation and mechanical ventilation were included in this prospective observational cohort study. At ICU admission, information on endotracheal aspirate purulence and hyperthermia was collected. In all patients, Gram stain and quantitative endotracheal aspirate culture (positive at 10(6) cfu/ml) were performed. In addition, leukocyte count, C-reactive protein and procalcitonin (PCT) levels were measured.

RESULTS

Ninety-eight severe acute exacerbations of COPD requiring intubation and mechanical ventilation were studied. Forty-nine bacteria were isolated at significant threshold in 40 exacerbations. Streptococcus pneumoniae (16%), methicillin-sensitive Staphylococcus aureus (16%) and Hemophilus influenzae (14%) were the most frequently isolated bacteria. PCT >0.5 ng/ml and positive Gram stain of endotracheal aspirate were independently associated with bacterial isolation in severe acute exacerbation of COPD. Positive Gram stain and PCT >0.5 ng/ml had a negative predictive value >95%. Similar results were found after excluding patients with prior antibiotic treatment.

CONCLUSION

Positive Gram stain of endotracheal aspirate and PCT >0.5 ng/ml are independently associated with bacterial isolation in severe acute exacerbation of COPD. These results could be helpful for future interventional studies aiming at reducing antibiotic use in these patients.

Antimicrobial treatment for ventilator-associated tracheobronchitis: a randomized, controlled, multicenter study

Introduction

Ventilator-associated tracheobronchitis (VAT) is associated with increased duration of mechanical ventilation. We hypothesized that, in patients with VAT, antibiotic treatment would be associated with reduced duration of mechanical ventilation.

Methods

We conducted a prospective, randomized, controlled, unblinded, multicenter study. Patients were randomly assigned (1:1) to receive or not receive intravenous antibiotics for 8 days. Patients with ventilator-associated pneumonia (VAP) prior to VAT and those with severe immunosuppression were not eligible. The trial was stopped early because a planned interim analysis found a significant difference in intensive care unit (ICU) mortality.

Results

Fifty-eight patients were randomly assigned. Patient characteristics were similar in the antibiotic (n = 22) and no antibiotic (n = 36) groups. Pseudomonas aeruginosa was identified in 32% of VAT episodes. Although no difference was found in mechanical ventilation duration and length of ICU stay, mechanical ventilation-free days were significantly higher (median [interquartile range], 12 [8 to 24] versus 2 [0 to 6] days, P < 0.001) in the antibiotic group than in the no antibiotic group. In addition, subsequent VAP (13% versus 47%, P = 0.011, odds ratio [OR] 0.17, 95% confidence interval [CI] 0.04 to 0.70) and ICU mortality (18% versus 47%, P = 0.047, OR 0.24, 95% CI 0.07 to 0.88) rates were significantly lower in the antibiotic group than in the no antibiotic group. Similar results were found after exclusion of patients with do-not-resuscitate orders and those randomly assigned to the no antibiotic group but who received antibiotics for infections other than VAT or subsequent VAP.

Conclusion

In patients with VAT, antimicrobial treatment is associated with a greater number of days free of mechanical ventilation and lower rates of VAP and ICU mortality. However, antibiotic treatment has no significant impact on total duration of mechanical ventilation.

Trial registration

ClinicalTrials.gov, number NCT00122057.

Relationship between immunosuppression and intensive care unit-acquired multidrug-resistant bacteria: a case-control study

OBJECTIVE

To determine the relationship between immunosuppression and intensive care unit (ICU)-acquired multidrug-resistant (MDR) bacteria.

DESIGN

Retrospective case-control study based on prospectively collected data.

SETTING

A 30-bed medical and surgical ICU.

PATIENTS

All patients hospitalized >48 hrs in the ICU were eligible during a 2-yr period.

INTERVENTIONS

Immunosuppression was defined as active solid or hematologic malignancy, leucopenia, or chronic immunosuppressive treatment. MDR bacteria were defined as methicillin-resistant Staphylococcus aureus, ceftazidime- or imipenem-resistant Pseudomonas aeruginosa, Acinetobacter baumannii, Stenotrophomonas maltophilia, and extending spectrum beta-lactamase producing Gram-negative bacilli. MDR bacteria screening (nasal, anal, and axilla swabs and tracheal aspirate in intubated patients) was performed at ICU admission and weekly. Only MDR bacteria isolated >48 hrs after ICU admission were taken into account; duplicates were excluded. Isolation measures were applied in all patients at ICU admission, in patients with MDR bacteria, and in patients with immunosuppression. Immunosuppressed patients (cases) were matched (1:1) with immunocompetent patients (controls) according to all the following criteria: age +/-5 yrs, Simplified Acute Physiology Score II +/-5, duration of ICU stay +/-3 days, and category of admission (medical/surgical). Risk factors for ICU-acquired MDR bacteria were determined using univariate and multivariate analyses.

MEASUREMENTS AND MAIN RESULTS

Of 1,065 eligible patients, nine patients were excluded for absence of MDR bacteria screening at ICU admission. One hundred thirty-three (12%) patients were immunosuppressed, and 128 (96%) of them were successfully matched. Mean time between ICU admission and first ICU-acquired MDR bacteria was 12 +/- 9 days. Incidence of MDR bacteria was significantly higher in cases than in controls (22 vs. 12 MDR bacteria/1000 ICU days, p = .004). However, immunosuppression was not independently associated with ICU-acquired MDR bacteria.Multivariate analysis identified prior antibiotic treatment and antibiotic treatment in the ICU as risk factors for ICU-acquired MDR bacteria (odds ratio [95% confidence interval] = 1.9 [1-3.6], p = .003; 11 [1.4-83], p = .02; respectively).

CONCLUSIONS

Immunosuppression is not independently associated with ICU-acquired MDR bacteria. However, infection control measures used in our ICU may have influenced this result.

Can dynamic indicators help the prediction of fluid responsiveness in spontaneously breathing critically ill patients?

OBJECTIVE

To investigate whether the respiratory changes in arterial pulse (DeltaPP) and in systolic pressure (DeltaSP) could predict fluid responsiveness in spontaneously breathing (SB) patients. Because changes in intrathoracic pressure during spontaneous breathing (SB) might be insufficient to modify loading conditions of the ventricles, performances of indicators were also assessed during a forced respiratory maneuver.

DESIGN

Prospective interventional study.

SETTING

A 34-bed university hospital medico-surgical ICU.

PATIENTS AND PARTICIPANTS

Thirty-two SB patients with clinical signs of hemodynamic instability.

INTERVENTION

A 500-ml volume expansion (VE).

MEASUREMENTS AND RESULTS

Cardiac index, assessed using transthoracic echocardiography, increased by at least 15% after VE in 19 patients (responders). At baseline, only dynamic indicators were higher in responders than in nonresponders (13+/-5% vs. 7+/-3%, p=0.003 for DeltaPP and 10+/-4% vs. 6+/-2%, p=0.002 for DeltaSP). Moreover, they significantly decreased after VE (11+/-5% to 6+/-4%, p<0.001 for DeltaPP and 8+/-4% to 6+/-3%, p<0.001 for DeltaSP). DeltaPP and DeltaSP areas under the ROC curve were high (0.81+/-0.08 and 0.82+/-0.08; p=0.888, respectively). A DeltaPP>or=12% predicted fluid responsiveness with high specificity (92%) but poor sensitivity (63%). The forced respiratory maneuver reproducing a dyspneic state decreased the predictive power.

CONCLUSIONS

Due to their lack of sensitivity and their dependence to respiratory status, DeltaPP and DeltaSP are clearly less reliable to predict fluid responsiveness during SB than in mechanically ventilated patients. However, when their baseline value is high without acute right ventricular dysfunction in a participating patient, a positive response to fluid is likely.