Microdialysis study of imipenem distribution in skeletal muscle and lung extracellular fluids of noninfected rats

The aim of this study was to investigate the imipenem distribution in muscle and lung interstitial fluids by microdialysis in rats and to compare the free concentrations in tissue with the free concentrations in blood. Microdialysis probes were inserted into the jugular vein, hind leg muscle, and lung. Imipenem recoveries in these three media were determined in each rat by retrodialysis by drug period before drug administration. Imipenem was infused intravenously at a dose of 120 mg . kg-1 over 30 min, and microdialysis samples were collected for 150 min. The whole study was conducted with nonhydrated rats (n=4) and hydrated rats (n=6) while the animals were under isoflurane anesthesia. The decay of free concentrations in blood, muscle, and lung with time were monoexponential; and the concentration profiles in these three media were virtually superimposed in both groups. Accordingly, the ratios of the area under the curve (AUC) for tissue (muscle or lung) to the AUC for blood were always virtually equal to 1. Compared to values previously determined with awake rats, clearance was reduced by 2 and 1.5 in nonhydrated and hydrated rats, respectively, but the volume of distribution was unchanged. By combining microdialysis in blood and tissues, it was possible to demonstrate that free imipenem concentrations were virtually identical in blood, muscle, and lung.

[On what grounds assessing the diagnosis of catheter-related infection?]

Clinical assessment of catheter-related infection is difficult. Microbiological techniques have not always been clearly evaluated. Indirect microbiological techniques, leaving the catheter on site are reserved to well tolerated infections. In case of catheter withdrawal, quantitative culture of the endovascular tip of the catheter should be preferred.

Norfloxacin-induced electroencephalogram alteration and seizures in rats are not triggered by enhanced levels of intracerebral glutamate

Pharmacokinetic-pharmacodynamic modeling of the electroencephalogram (EEG) effect was combined with intracerebral glutamate determinations using microdialysis for rats receiving norfloxacin intravenously (150 mg/kg of body weight). The EEG effect (accompanied by tremors and seizures) was consistently observed without glutamate level modifications. Therefore, norfloxacin-inducted seizures are not triggered by intracerebral glutamate level enhancement.

Pharmacokinetic-pharmacodynamic modelling of the electroencephalogram effect of imipenem in rats with experimental hypovolaemia or endotoxaemia

OBJECTIVES

The epileptogenic activity of imipenem in rats with experimentally induced hypovolaemia or endotoxaemia was investigated by pharmacokinetic-pharmacodynamic modelling of the electroencephalogram effect.

METHODS

Hypovolaemia was induced by removal of 30% of the blood volume and endotoxaemia by intravenous lipopolysaccharide injection.

RESULTS

Imipenem clearance and volume of distribution values of 16.4+/-1.1 mL/min per kg and 357+/-49 mL/kg (mean+/-S.E.M.) in healthy rats (n=5), were significantly reduced in hypovolaemic (n=6) and endotoxaemic (n=6) animals. A dose reduction from 250 mg/kg to 120 mg/kg was necessary in endotoxaemic rats. The pharmacokinetic-pharmacodynamic model with an effect compartment previously developed in healthy rats described the data adequately and pharmacodynamic parameters in hypovolaemic and endotoxaemic rats were not significantly different from corresponding values estimated in the control group.

CONCLUSION

Hypovolaemia and endotoxaemia only had an effect on imipenem pharmacokinetics.

Analyse critique de la littérature sur l’utilisation comparée de deux antiseptiques lors du cathétérisme vasculaire ou rachidien

OBJECTIVES

To analyze the most pertinent data from the literature concerning the use of an antiseptic solution before the elaboration of invasive procedures such as blood cultures, insertion of peripheral or central intravenous catheters, and arterial or epidural catheters, and to identify, if any, the "ideal" antiseptic or, at least, the most efficient.

DATA SOURCES

Review of the literature. Data collected from the Medline database concerning experimental, clinical and basic research studies published between 1966 and 2003 and a manual research of references of relevant papers.

RESULTS

After a brief historic and pharmacological reminder, the results of experimental and clinical studies are presented. Concerning the clinical studies, they concerned almost exclusively iodine products and chlorhexidine. These comparative studies are classified according to the punction site and the antiseptic solution used.

CONCLUSION

Even if the in vitro studies favor iodine products, chlorhexidine in alcoholic solution seems more efficient than povidone iodine in aqueous solution in the clinical setting. Several explanations are suggested to understand the in vitro/in vivo discordances. The place of povidone iodine in alcoholic solution, whose performances on the healthy skin are similar to those of alcoholic chlorhexidine, is being in evaluation.

Pharmacokinetics and pharmacodynamics of sequential intravenous and subcutaneous teicoplanin in critically ill patients without vasopressors

OBJECTIVE

To compare the pharmacokinetic parameters of sequential intravenous and subcutaneous teicoplanin in the plasma of surgical intensive care unit patients.

DESIGN AND SETTING

Prospective, randomized, crossover study in the surgical ICU of a university hospital.

PATIENTS

Twelve patients with a suspected nosocomial infection, a serum albumin level higher than 10 g/l, body mass index less than 28 kg/m(2), and estimated creatinine clearance higher than 70 ml/min.

INTERVENTIONS

Teicoplanin was first administered intravenously as a loading dose of 6 mg/kg per 12 h for 48 h and then continued at a daily dose of 6 mg/kg. On the fourth day patients were randomized in two groups according to the order of the pharmacokinetic studies.

MEASUREMENTS AND RESULTS

Serial plasma samples were obtained to measure teicoplanin levels. Compared with a 30-min intravenous infusion the peak concentration of teicoplanin after a 30-min subcutaneous administration occurred later (median 7 h, range 5-18) and was lower (16 micro g/ml, 9-31; vs. 73, 53-106). Despite large and unpredictable interindividual differences no significant differences between subcutaneous and intravenous administration were observed in: trough antibiotic concentrations (10 micro g/ml, 6-24; vs. 9, 5-30), the area under the teicoplanin plasma concentration vs. time curves from 0 to 24 h (AUC(0-24h); 309 micro g/ml per minute, 180-640; vs. 369, 171-955), the proportion of the dosing interval during which the plasma teicoplanin concentration exceeded 10 micro g/ml (96%, 0-100%; vs. 79%, 13-100%), and the ratio of AUC(0-24h) to 10 (77, 45-160; vs. 92, 43-239).

CONCLUSIONS

In critically ill patients without vasopressors a switch to the subcutaneous teicoplanin after an initial intravenous therapy seems to give comparable pharmacodynamic indexes of therapeutic success.

Pharmacokinetic-pharmacodynamic modeling of the electroencephalogram effect of norfloxacin in rats

A previously developed pharmacokinetic-pharmacodynamic (PK-PD) modeling approach was used to investigate the epileptogenic activity of norfloxacin as a representative antibiotic with concentration-dependent antimicrobial activity. Rats received an intravenous infusion of norfloxacin at a rate of 5 mg kg of body weight(-1) min(-1) over 30 min. Blood samples were collected for drug assay, and an electroencephalogram (EEG) was recorded during infusion and postinfusion. An important delay was observed between concentrations of norfloxacin in plasma and the EEG effect. Indirect effect models failed to describe these data, which were successfully fitted by using an effect compartment model with a spline function to describe the relationship between effect and concentration at the effect site, as previously observed with imipenem. The robustness of the PK-PD model was then assessed by keeping the dose constant but increasing the duration of infusion to 120 and 240 min. Although this was accompanied by PK modifications, PD parameters did not vary significantly, and the PK-PD model still applied. In conclusion, the successful PK-PD modeling of the norfloxacin EEG effect in rats should be considered to predict and reduce the epileptogenic risk associated with this antibiotic as a representative fluoroquinolone (E. Fuseau and L. B. Sheiner, Clin. Pharmacol. Ther. 35:733-741, 1984).

Efficacy of beta-lactams for treating experimentally induced pneumonia due to a carbapenem-hydrolyzing metallo-beta-lactamase-producing strain of Pseudomonas aeruginosa

A rat pneumonia model was established with a Pseudomonas aeruginosa strain that produced the plasmid-encoded metallocarbapenemase VIM-2. A significant decrease in lung bacterial titers was observed when imipenem, cefepime, ceftazidime, and piperacillin-tazobactam were given at the highest doses recommended for humans, despite their high MICs. Aztreonam at high doses produced a similar decrease in bacterial titers.

Pharmacokinetic-pharmacodynamic modeling of electroencephalogram effect of imipenem in rats with acute renal failure

The epileptogenic activity of imipenem was investigated in rats with experimental renal failure induced by uranyl nitrate injection by using electroencephalogram (EEG) recording and a pharmacokinetic-pharmacodynamic model including an effect compartment. Results previously obtained with healthy rats were used to estimate the dose of imipenem required to induce an observable but nonlethal EEG effect on the assumption that only the pharmacokinetic parameters of the model would be affected by renal failure. Good agreement was observed between the predicted and observed effects.

Co-amoxiclav pharmacokinetics during posttraumatic hemorrhagic shock

OBJECTIVE

To determine the effects of severe trauma with hemorrhagic shock on amoxicillin and clavulanate concentrations in plasma and their pharmacokinetics.

DESIGN

A prospective, open, descriptive study.

SETTING

A 12-bed, adult surgical intensive care unit in a university-affiliated hospital in France.

SUBJECTS

Subjects were 12 patients (10 men, 2 women) with severe trauma: median (range) Injury Severity Score, 38 (17-48); Acute Physiology and Chronic Health Evaluation II, 16 (7-38); Simplified Acute Physiology Score II, 41 (23-77). Also enrolled were 12 healthy volunteers who were matched on age (+/-5 yrs), gender, and body-surface area (+/-20 cm2). All the trauma patients suffered hemorrhagic shock defined as the association of at least one episode of systolic blood pressure <90 mm Hg and an intravascular volume expansion >2000 mL between trauma and surgery.

INTERVENTION

Prophylactic perioperative administration of 2 g of amoxicillin and 0.2 g of clavulanate in combination during the first 12 hrs posttrauma in patients, and at the start of the pharmacokinetic study in volunteers.

MEASUREMENTS AND MAIN RESULTS

Serial plasma samples (n = 13) were obtained after the first antibiotic administration to measure antibiotic levels by using high-performance liquid chromatography assays. Compared with volunteers, trauma patients had higher plasma amoxicillin and clavulanate concentrations, attributed to a reduction of the volume of distribution (p =.001 and p =.06, respectively) and, to a lesser extent, of the total body clearance (p =.09 and p =.20, respectively). Consequently, amoxicillin and clavulanate elimination half-lives were similar for the two groups of subjects. The interindividual variabilities for all the amoxicillin pharmacokinetic parameters were higher in patients.

CONCLUSIONS

In trauma patients with hemorrhagic shock requiring surgery, the administration of 2 g of amoxicillin and 0.2 g of clavulanate seems adequate, according to the antibiotic concentrations observed in plasma for both drugs. However, further studies exploring antibiotic concentrations in tissues are warranted.

Analgesic efficacy and safety of nefopam vs. propacetamol following hepatic resection

In order to compare the morphine-sparing effect, analgesic efficacy and tolerance of nefopam and propacetamol given at their highest recommended doses, 120 patients undergoing elective hepatic resection were randomly assigned to receive postoperative intravenous patient-controlled analgesia with morphine alone, or in combination with nefopam (20 mg.4 h-1) or propacetamol (2 g.6 h-1). Compared with the control group (43 [7-92] mg), median [range] cumulative morphine consumption for 24 h after the study started was halved in the nefopam group (21 [3-78] mg, p <0.001) and 20% lower in the propacetamol group (35 [6-84] mg, p = 0.15). Analgesia was superior in the nefopam group despite the lower morphine consumption. Adverse effects were comparable in the three groups, except for significantly more nausea in the control group (39% vs. 17 and 26% in the nefopam and propacetamol groups, respectively) and more sweating in the nefopam group (17% vs. 0 and 3% in the control and propacetamol groups, respectively). Overall patient satisfaction was better (p < 0.001) in patients given nefopam (97%) than those receiving morphine alone (82%) or propacetamol (74%).

[Catheter-related infection in intensive care. Physiopathology, diagnosis, treatment and prevention]

PURPOSE

To review the mechanisms, diagnosis, treatment and prophylaxis of catheter-related sepsis in intensive care unit patients.

DATA SOURCES

A Medline research of the English- or French-language reports published between 1966 and 2000 and a manual research of references of relevant papers.

STUDY SELECTION

Experimental, clinical and basic research studies related to catheter-related sepsis.

DATA EXTRACTION

Data in selected articles were reviewed, and relevant clinical information was extracted.

DATA SYNTHESIS

Infection remains the major complication related to catheter insertion. No bacteriological exam or systematic catheter change is required in the absence of infection suspicion. In the intensive care unit, and without septic shock, the surveillance of skin cultures at the catheter insertion site or the time to positivity of hub-blood versus peripheral-blood culture determination may reduce the number of unnecessary removed catheters. Catheter change over a guidewire is not recommended because of the risk of dissemination of infection. When the catheter is removed, a quantitative culture is warranted. The treatment of catheter-related sepsis is based on catheter removal. The use of antibiotics is limited to some organisms or when the infection is complicated. The persistence of fever and positive blood cultures 72 h after catheter removal require to look for dissemination of infection or septic thrombophlebitis, especially if S. aureus or Candida are incriminated. The treatment of infection without catheter removal is not recommended in the intensive care unit because of a high risk of treatment failure. Compliance with catheter care guidelines and continuing quality improvement programs are the two major procedures in reducing catheter infection.

CONCLUSIONS

Improved understanding of the pathophysiology of catheter-related sepsis has led to improved prevention. Compliance with catheter care guidelines and continuing quality improvement programs are majors procedures to reduce the risk of catheter infection.

Chlorhexidine versus povidone iodine in preventing colonization of continuous epidural catheters in children: a randomized, controlled trial

BACKGROUND

Chlorhexidine is better than povidone iodine for skin preparation before intravascular device insertion or blood culture collection, but it is not known whether chlorhexidine is superior in reducing colonization of continuous epidural catheters.

METHODS

Children requiring an epidural catheter for postoperative analgesia longer than 24 h were randomly assigned to receive skin preparation with an alcoholic solution of 0.5% chlorhexidine or an aqueous solution of 10% povidone iodine before catheter insertion. Using surgical aseptic techniques, catheters were inserted into either the lumbar or the thoracic epidural space based on the preferences of the anesthesia team, on clinical indication, or both. Immediately before epidural catheter removal, their insertion site and hub were qualitatively cultures. After their removal, the catheter tips were quantitatively cultured. Catheters were classified as colonized when their tips yielded 1,000 or more colony-forming units/ml in cultures.

RESULTS

Of 100 randomly assigned patients, 96 were evaluable. The clinical characteristics of the patients and the risk factors for infection were similar in the two groups. Catheters were kept in place for a median (range) duration of 50 (range, 21-100) h. Catheters inserted after skin preparation with chlorhexidine were one sixth as likely and less quickly to be colonized as catheters inserted after skin preparation with povidone iodine (1 of 52 catheters [0.9 per 100 catheter days] vs. 5 of 44 catheters [5.6 per 100 catheter days]; relative risk, 0.2 [95% confidence interval, 0.1-1.0]; P = 0.02). Coagulase-negative staphylococci were the only colonizing microorganisms recovered, and the skin surrounding the catheter insertion site was the origin of all the colonizing microorganisms.

CONCLUSIONS

Compared with aqueous povidone iodine, the use of alcoholic chlorhexidine for cutaneous antisepsis before epidural catheter insertion reduces the risk of catheter colonization in children.

Gram staining of protected pulmonary specimens in the early diagnosis of ventilator-associated pneumonia

We evaluated prospectively the use of Gram staining of protected pulmonary specimens to allow the early diagnosis of ventilator-associated pneumonia (VAP), compared with the use of 60 bronchoscopic protected specimen brushes (PSB) and 126 blinded plugged telescopic catheters (PTC) obtained from 134 patients. Gram stains were from Cytospin slides; they were studied for the presence of microorganisms in 10 and 50 fields by two independent observers and classified according to their Gram stain morphology. Quantitative cultures were performed after serial dilution and plating on appropriate culture medium. A final diagnosis of VAP, based on a culture of > or = 10(3) c.f.u. ml-1, was established after 81 (44%) samplings. When 10 fields were analysed, a strong relationship was found between the presence of bacteria on Gram staining and the final diagnosis of VAP (for PSB and PTC respectively: sensitivity 74 and 81%, specificity 94 and 100%, positive predictive value 91 and 100%, negative predictive value 82 and 88%). The correlation was less when we compared the morphology of microorganisms observed on Gram staining with those of bacteria obtained from quantitative cultures (for PSB and PTC respectively: sensitivity 54 and 69%, specificity 86 and 89%, positive predictive value 72 and 78%, negative predictive value 74 and 84%). Increasing the number of fields read to 50 was associated with a slight decrease in specificity and positive predictive value of Gram staining, but with a small increase in its sensitivity and negative predictive value. The results obtained by the two observers were similar to each other for both numbers of fields analysed. Gram staining of protected pulmonary specimens performed on 10 fields predicted the presence of VAP and partially identified (using Gram stain morphology) the microorganisms growing at significant concentrations, and could help in the early choice of the treatment of VAP. Increasing the number of fields read or having the Gram stain analysed by two independent individuals did not improve the results.

Ceftriaxone pharmacokinetics during iatrogenic hydroxyethyl starch-induced hypoalbuminemia: a model to explore the effects of decreased protein binding capacity on highly bound drugs

BACKGROUND

Although various drugs used by anesthesiologists highly bind to plasma proteins, the impact of iatrogenically induced hypoproteinemia on their pharmacologic effects has never been investigated. The authors determined the pharmacokinetics of ceftriaxone, a cephalosporin that binds strongly to albumin in postsurgical patients with hydroxyethyl starch-induced hypoalbuminemia.

METHODS

Eleven hypoalbuminemic (serum albumin < 25 g/l) patients and age (+/- 5 yr)-, sex-, and body surface area (+/- 10%)-matched healthy volunteers received a 2-g ceftriaxone dose infused over a 15-min period. Fourteen venous blood samples were collected during the 24-h study period. Free ceftriaxone concentrations were determined by ultrafiltration. Antibiotic concentrations in plasma and ultrafiltrate were measured by ion-paired reversed-phase chromatography. The pharmacokinetic parameters derived from total and free antibiotic concentrations were determined using a noncompartmental method. Data are expressed as median and range.

RESULTS

The pharmacokinetic parameters derived from total ceftriaxone concentrations were similar for the two groups, except for the median corrected volume of distribution at steady state, which was increased (P = 0.05) to 0.18 l/kg (range, 0. 11-0.29 l/kg) in patients, compared with 0.15 l/kg (range, 0.13-0.22 l/kg) in volunteers. The area under the free ceftriaxone concentration-time curve was twice as high in patients as in volunteers (median 192, range 114-301 vs. median 122, range 84-169 h. mg-1. l-1;P = 0.03). Moreover, the free ceftriaxone concentration remained more than 4 mg/l during more time in patients (median, 16. 7; range, 12.6-21.4 vs. median, 11.1; range, 6.0-19.0 h; P = 0.03).

CONCLUSIONS

Compared with healthy volunteers, patients with iatrogenic hypoalbuminemia have higher free ceftriaxone concentrations during the 24 h after antibiotic administration. This modification increases drug distribution into extravascular space and may enhance effectiveness.

Efficacies of imipenem, meropenem, cefepime, and ceftazidime in rats with experimental pneumonia due to a carbapenem-hydrolyzing beta-lactamase-producing strain of Enterobacter cloacae

The antibacterial activities of imipenem-cilastatin, meropenem-cilastatin, cefepime and ceftazidime against Enterobacter cloacae NOR-1, which produces the carbapenem-hydrolyzing beta-lactamase NmcA and a cephalosporinase, and against one of its in vitro-obtained ceftazidime-resistant mutant were compared by using an experimental model of pneumonia with immunocompetent rats. The MICs of the beta-lactams with an inoculum of 5 log(10) CFU/ml were as follows for E. cloacae NOR-1 and its ceftazidime-resistant mutant, respectively: imipenem, 16 and 128 microg/ml, meropenem, 4 and 32 microg/ml, cefepime, <0.03 and 1 microg/ml, and ceftazidime, 1 and 512 microg/ml. The chromosomally located cephalosporinase and carbapenem-hydrolyzing beta-lactamase NmcA were inducible by cefoxitin and meropenem in E. cloacae NOR-1, and both were stably overproduced in the ceftazidime-resistant mutant. Renal impairment was induced (uranyl nitrate, 1 mg/kg of body weight) in rats to simulate the human pharmacokinetic parameters for the beta-lactams studied. Animals were intratracheally inoculated with 8.5 log(10) CFU of E. cloacae, and therapy was initiated 3 h later. At that time, animal lungs showed bilateral pneumonia containing more than 6 log(10) CFU of E. cloacae per g of tissue. Despite the relative low MIC of meropenem for E. cloacae NOR-1, the carbapenem-treated rats had no decrease in bacterial counts in their lungs 60 h after therapy onset compared to the counts for the controls, regardless of whether E. cloacae NOR-1 or its ceftazidime-resistant mutant was inoculated. A significant decrease in bacterial titers was observed for the ceftazidime-treated rats infected with E. cloacae NOR-1 only. Cefepime was the only beta-lactam tested effective as treatment against infections due to E. cloacae NOR-1 or its ceftazidime-resistant mutant.

Transplantation of three adult patients with one cadaveric graft: wait or innovate

Graft shortage continues to prolong waiting times for adults requiring liver transplantation. Living related donor transplantation is possible for only a small minority of adults. The techniques for in situ splitting of the liver used for right and left hepatectomies in living donors were adapted to a combined split-liver-domino procedure to obtain right and left hemiliver grafts from a patient undergoing total hepatectomy with liver transplantation for a metabolic disorder. The two grafts were adequate in size and function for transplantation to two adults with low priority for regular cadaver grafts. More frequent use of split-liver techniques in cadaver donors could considerably reduce the graft shortage and waiting time for adult liver recipients.

[Colonization by methicillin-resistant Staphylococcus aureus is a predictive factor for the resistance phenotype of an infectious strain of S. aureus]

OBJECTIVE

To assess the predictive value of a previous colonization with methicillin-resistant Staphylococcus aureus for the resistance pattern of a bacteriological specimen significantly positive to S. aureus.

STUDY DESIGN

Retrospective study of patients' files.

PATIENTS

Patients admitted for at least 48 hours in a surgical intensive care unit from April 1, 1996 to December 31, 1997.

METHODS

Collection of patients' characteristics and chronology of positive microbiological specimens with methicillin-susceptible (MSSA) or -resistant (MRSA) S. aureus from medical and laboratory records. During the study period, screening for nasal or perineal colonization with MRSA was systematically performed on admission and weekly thereafter.

RESULTS

The files of 540 patients were reviewed. MSSA and MRSA infections occurred in 7% (39/540) and 4% (20/540) of the patients respectively. By opposition with MSSA infections, MRSA infections occurred more frequently in patients previously colonized with MRSA (13 infections in 63 colonized patients [21%] versus 7 infections in 477 non-colonized patients [2%], odds ratio = 18, confidence interval: 6-51, P < 0.0001). The median delay between colonization and infection was 5 days. The positive and negative predictive values for previous colonization with MRSA to predict infection with MRSA in presence of a bacteriological specimen significantly positive with S. aureus were 81 and 84%, respectively.

CONCLUSION

The probabilistic use of a glycopeptide in presence of a bacteriological specimen significantly positive with S. aureus should be limited to patients already colonized with MRSA, in order to decrease the abusive administration of these antibiotics.

Chlorhexidine compared with povidone-iodine as skin preparation before blood culture. A randomized, controlled trial

BACKGROUND

Chlorhexidine is better than povidone-iodine for care of catheter sites, but it is not known whether chlorhexidine is superior in reducing blood culture contamination.

OBJECTIVE

To determine whether alcoholic chlorhexidine is a more effective skin antiseptic for collection of blood cultures than aqueous povidone-iodine.

DESIGN

Randomized, controlled trial.

SETTING

Three adult intensive care units in a French university hospital.

PATIENTS

403 adults who had at least one blood culture drawn through a peripheral vein.

INTERVENTIONS

Patients were randomly assigned to receive skin preparation with an aqueous solution of 10% povidone-iodine or an alcoholic solution of 0.5% chlorhexidine before phlebotomy.

MEASUREMENTS

Contamination rates of blood cultures.

RESULTS

Of 2041 blood cultures collected in 403 patients, 124 yielded pathogens. Chlorhexidine reduced the incidence of blood culture contamination more than povidone-iodine (14 of 1019 cultures [1.4%] compared with 34 of 1022 cultures [3.3%]; odds ratio, 0.40 [95% CI, 0.21 to 0.75]; P = 0.004).

CONCLUSION

Skin preparation with alcoholic chlorhexidine is more efficacious than skin preparation with aqueous povidone-iodine in reducing contamination of blood cultures.

Treatment of experimental pneumonia in rats caused by a PER-1 extended-spectrum beta-lactamase-producing strain of Pseudomonas aeruginosa

The antibacterial activity of imipenem, cefepime and piperacillin-tazobactam alone or in combination with amikacin against a Pseudomonas aeruginosa strain producing an extended-spectrum beta-lactamase (PER-1) were compared using an experimental model of pneumonia in non-leucopenic rats. Animals were infected intratracheally with 8.0 +/- 0.4 log10 cfu of P. aeruginosa, and therapy was initiated 3 h later, by which time animal lungs showed bilateral pneumonia containing >7 log10 P. aeruginosa cfu/g of tissue. Since rats eliminate antibiotics much more rapidly than humans, renal impairment was induced in all animals to simulate the pharmacokinetic parameters of humans. MICs determined using an inoculum of 4 log10 cfu/mL were as follows: imipenem, 1 mg/L; cefepime, 8 mg/L; piperacillin-tazobactam, 32 mg/L; and amikacin, 16 mg/L. A noticeable inoculum effect was observed with the four antimicrobial agents tested, which was greatest for cefepime and piperacillin-tazobactam. In-vitro studies indicated that imipenem was the beta-lactam with the greatest bactericidal effect and that amikacin was synergic only in combination with cefepime and imipenem. Cefepime and piperacillin-tazobactam alone failed to decrease bacterial counts in the rats' lungs 60 h after therapy onset, whereas imipenem and, to a lesser extent, amikacin significantly reduced the number of viable microorganisms. Combination of amikacin with any of the three beta-lactams tested was synergic, despite a high amikacin MIC for the infecting strain. These results paralleled our in-vitro data showing a marked inoculum effect for cefepime and piperacillin-tazobactam. Based on the results of this study, the best treatment for infections caused by this type of extended-spectrum beta-lactamase-possessing strain would be imipenem plus amikacin.

Pharmacokinetics of cefpirome during the posttraumatic systemic inflammatory response syndrome

OBJECTIVE

To determine the pharmacokinetic parameters of cefpirome, a new so-called fourth-generation cephalosporin, in previously healthy trauma patients with posttraumatic systemic inflammatory response syndrome (SIRS) and to compare them to parameters obtained in matched, healthy volunteers.

DESIGN

A prospective study.

SETTING

12-bed surgical intensive care unit in a university hospital.

PATIENTS

9 severe [Injury Severity Score, median (range) 29 (16-50)] trauma patients on mechanical ventilation with proven or suspected cefpirome-susceptible nosocomial infection, with no renal or hepatic failure, and healthy volunteers matched for age (+/- 5 years), sex, and body surface area (+/- 10%) were enrolled. All were men.

INTERVENTIONS

Cefpirome (2 g twice daily) was continuously infused over a 0.5 h period alone or concomitantly with ciprofloxacin (400 mg over 1 h, twice daily).

MEASUREMENTS AND MAIN RESULTS

Antibiotic concentrations in plasma were measured by high-performance liquid chromatography; their pharmacokinetic parameters were evaluated at 12 time points after the first drug administration using a noncompartmental model. Cefpirome pharmacokinetic parameters for the two groups were similar despite a wider variation for trauma patients. Specifically, the median (range) time during which the cefpirome concentration in plasma remained over 4 mg/l (corresponding to the French lower cutoff determining cefpirome susceptibility) was 9.5 (7- > 12) and 9 (8-12) h for trauma patients and healthy volunteers, respectively. In the group of five patients receiving combined antibiotic therapy, the interindividual variability of pharmacokinetics was wider for ciprofloxacin than for cefpirome.

CONCLUSION

No major pharmacokinetic modification was noted when cefpirome was given to trauma patients with posttraumatic SIRS without significant organ failure, indicating that no dosage adjustment seems required in this population. However, larger studies including determination of antibiotic levels in tissues are warranted to confirm these results.

Renal effects of low-dose dopamine during vasopressor therapy for posttraumatic intracranial hypertension

OBJECTIVE

To investigate the effects of low-dose dopamine (Dop) on renal hemodynamics and function in patients with brain trauma receiving norepinephrine (NE).

DESIGN

Prospective clinical study.

SETTING

Surgical intensive care unit of a university hospital.

PATIENTS

20 stable, non-septic, mechanically ventilated, sedated patients with brain trauma and normal renal function treated with intravenous NE (0.11-0.65 microg/kg per min) to maintain an adequate cerebral perfusion pressure (> 60 mmHg).

INTERVENTIONS

Two successive 1-h study periods with NE alone then NE + Dop (2 microg/kg per min). During each period, creatinine (Cl(CREAT)), sodium (Cl(Na)), potassium (Cl(K)), osmolar (Cl(OSM)) and free water (Cl(H2O)), clearances were measured in all the patients. Effective renal blood flow (ERBF, para-aminohippurate clearance) and glomerular filtration rate (GFR, inulin clearance) were measured in 7 of the 20 patients.

RESULTS

Dop during NE infusion induced increases in urine flow and natriuresis which were not correlated with possible changes in arterial pressure. Cl(CREAT), GFR and their difference remained unchanged, whereas ERBF tended to increase. Fractional sodium excretion [100 x (Cl(Na)/Cl(CREAT)] and C1(K) increased during Dop infusion.

CONCLUSION

The mechanism of Dop-induced natriuresis during NE infusion in brain trauma patients seems mainly related to a direct tubular effect of the drug.

Efficacies of cefepime, ceftazidime, and imipenem alone or in combination with amikacin in rats with experimental pneumonia due to ceftazidime-susceptible or -resistant Enterobacter cloacae strains

The antibacterial activities of human regimens of cefepime, ceftazidime, and imipenem alone or in combination with amikacin against an isogenic pair of Enterobacter cloacae strains (wild type and its corresponding derepressed cephalosporinase mutant) were compared by using our nonlethal model of pneumonia with 180 immunocompetent rats. Compared with untreated animals, all beta-lactam-treated rats, except those inoculated with the mutant isolate and receiving ceftazidime, had significantly lower bacterial counts in their lungs 60 h after the onset of therapy. Although the combination of a beta-lactam and amikacin was more bactericidal than each corresponding antimicrobial agent alone, true synergy was noted only with cefepime and imipenem against the constitutive derepressed strain.

Pharmacokinetics and absolute bioavailability of ciprofloxacin administered through a nasogastric tube with continuous enteral feeding to critically ill patients

OBJECTIVE

To determine the pharmacokinetics and absolute bioavailability of ciprofloxacin in 12 critically ill patients receiving continuous enteral feeding.

DESIGN

a prospective, cross-over study.

SETTING

12-bed surgical intensive care unit in a University Hospital.

PATIENTS

12 stable critically ill patients on mechanical ventilation and receiving continuous enteral feeding (Normoreal fibres) without diarrhea or excessive residual gastric contents ( < 200 ml/4 h). None had gastro-intestinal disease, renal insufficiency (estimated creatinine clearance > or = 50 ml/min) or was receiving medications that could interfere with ciprofloxacin absorption or metabolism.

MEASUREMENTS AND MAIN RESULTS

The study was carried out after the fourth (steady state) b. i. d. intravenous (i. v.) 1-h infusion of 400 mg and the second b. i. d. nasogastric (NG) dose of 750 mg (crushed tablet in suspension). Plasma concentrations were measured by high-performance liquid chromatography. The median (range) peak concentration after i. v. infusion was 4.1 (1.5-7.4) mg/l, and that after NG administration was 2.3 (0.7-5.8) mg/l, occurring 1.25 (0.75-3.33) h after dosing. The median [range] areas under plasma concentration-time curves were similar for the two administration routes (10.3 [3.3-34.6] and 8.4 [3.6-53.4] for i.v. infusion and NG administration, respectively). Ciprofloxacin bioavailability ranges from 31 to 82 % (median, 44%).

CONCLUSIONS

In tube-fed critically ill patients, a switch to the NG ciprofloxacin after initial i. v. therapy to simplify the treatment of severe infections is restricted to those for whom serial assessments of ciprofloxacin levels are routinely available.

[Procalcitonin in severe trauma]

The diagnosis of infection in systemic inflammatory syndrome response is difficult but essential for correct patient management. Procalcitonin is a new biochemical marker of infection especially for bacterial infection. Procalcitonin and C-reactive protein (CRP) were prospectively studied in 21 severe trauma patients and correlated with the trauma severity and the occurrence of infection. At the early post-traumatic period (admission to day 3) procalcitonin and CRP are correlated with the severity of trauma (early volume loading and markers of tissue injury) as did typically acute inflammatory proteins. At the late post-traumatic period (day 7) while CRP concentrations remain elevated in all patients, procalcitonin concentrations are only raised in septic patients even if inflammation's clinical signs persist.

Circulating cardiac troponin I in trauma patients without cardiac contusion

OBJECTIVES

To describe the evolution and the diagnostic value of cardiac troponin I (cTnI) and to relate its concentrations with the indicators of injury in trauma patients.

DESIGN

Prospective, observational study of 17 young, previously healthy, mechanically-ventilated patients during the early post-traumatic period in the Surgical ICU of a University Hospital.

METHODS

Serial measurements of serum cTnI, total creatine kinase activity (CKtot) and its isoenzyme MB (CK-MB) (on admission, 12 h later, then daily for 7 days), clinical data and repeated electrocardiographic (ECG) and transesophageal echocardiographic (TEE) recordings.

RESULTS

Rhabdomyolysis was observed in all the patients with a significant relationship between CK-MB and CKtot. Despite the fact that no patient demonstrated ECG or TEE signs of myocardial contusion, elevated serum levels of cTnI were observed in six patients (35%) without obvious dilutional interference. As compared with the others, these patients exhibited a more frequent arterial hypotension (83% vs 18%, p = 0.035), required greater volume expansion on day 1 (22,000 vs 8,500 ml, p = 0.027) and usually demonstrated early (83% vs 9%, p = 0.005) and late (66% vs 9%, p = 0.028) multiple organ dysfunction syndrome.

CONCLUSIONS

Taking into account the high reported sensitivity and specificity of cTnI dosage, the present results suggest cTnI can play a role in the evaluation of indirect myocardial injury following traumatic shock.

Cefepime and amikacin synergy in vitro and in vivo against a ceftazidime-resistant strain of Enterobacter cloacae

The activities of cefepime and amikacin alone or in combination against an isogenic pair of Enterobacter cloacae strains (wild type and stably derepressed, ceftazidime-resistant mutant) were compared using an experimental model of pneumonia in non-leucopenic rats. Animals were infected by administering 8.4 log10 cfu of E. cloacae intratracheally, and therapy was initiated 12 h later. At that time, the animals' lungs showed bilateral pneumonia and contained more than 7 log10 E. cloacae cfu/g tissue. Because rats eliminate amikacin and cefepime much more rapidly than humans, renal impairment was induced in all animals to simulate the pharmacokinetic parameters of humans. In-vitro susceptibilities showed an inoculum effect with cefepime proportional to the bacterial titre against the two strains, but more pronounced with the stably derepressed mutant strain, whereas with bacterial concentrations of up to 7 log10 cfu/mL, no inoculum effect was observed with amikacin. In-vitro killing indicated that antibiotic combinations were synergic only at intermediate concentrations. At peak concentrations, the combination was merely as effective as amikacin alone. At trough concentrations, a non-significant trend towards the superiority of the combination over each antibiotic alone was noted. Moreover, cefepime was either bacteriostatic or permitted regrowth of the organisms in the range of antibiotic concentrations tested. Although each antibiotic alone failed to decrease bacterial counts in the lungs, regardless of the susceptibility of the strain used, the combination of both antibiotics was synergic and induced a significant decrease in the lung bacterial count 24 h after starting therapy when compared with tissue bacterial numbers in untreated animals or animals treated with either antibiotic alone. No resistant clones emerged during treatment with any of the antibiotic regimens studied.

Procalcitonin and C-reactive protein during the early posttraumatic systemic inflammatory response syndrome

OBJECTIVES

To describe the initial evolution of serum procalcitonin (PCT) and C-reactive protein (CRP) in previously healthy adult trauma patients and to compare the relationship of the expression of these two proteins with indicators of trauma severity.

DESIGN

Prospective, descriptive, longitudinal study.

SETTING

Surgical ICU in an university hospital.

PATIENTS

Twenty-one patients admitted during the first posttraumatic 3 h exhibiting an Injury Severity Score (ISS) between 16 and 50 were enrolled.

MEASUREMENTS

Blood sampling was performed on admission and on posttraumatic days 0.5, 1, 2 and 3 to assess serum levels of PCT and CRP. Total creatine kinase (CKtot) and lactate dehydrogenase (LDHtot) activities in the serum were used as tissue damage indicators.

RESULTS

PCT exhibited an early and transient increase in serum levels similar to a more delayed change of CRP levels. Peak PCT and peak CRP were related to the ISS, the extent of tissue damage and the amount of fluid replacement during the first day. During the first 3 posttraumatic days, 90% of the patients exhibited a generalized inflammatory syndrome without infection.

CONCLUSIONS

An early and transient release of PCT into the circulation was observed after severe trauma and the amount of circulating PCT seemed proportional to the severity of tissue injury and hypovolemia, yet unrelated to infection. The predictive value of both PCT and CRP for a forthcoming multiple organ failure still remains to be clarified.

Cefepime and amikacin synergy against a cefotaxime-susceptible strain of Enterobacter cloacae in vitro and in vivo

We developed an experimental model of pneumonia to evaluate the efficacy of new antibiotic regimens against Enterobacter cloacae. Rats were infected by administering 8.5 log10 cfu E. cloacae intratracheally, and therapy was initiated 24 h later. At that time, animals' lungs showed bilateral pneumonia containing more than 7 log10 cfu/g of tissue. Because rats eliminate amikacin and cefepime much more rapidly than humans, renal impairment was induced in all animals to simulate the pharmacokinetic parameters in humans. Using this model, we compared the bactericidal activities of cefepime and amikacin alone or in combination against the same cefotaxime-susceptible E. cloacae strain. The MICs of cefepime and amikacin for this strain were 0.5 and 2 mg/L, respectively. In-vitro killing studies showed that antibiotic combinations were synergic only at intermediate concentrations. At peak concentrations, the combination was only as effective as amikacin alone. At trough concentrations, a non-significant trend towards the superiority of the combination over cefepime alone was found. In-vivo studies showed that each antibiotic alone failed to decrease bacterial counts in the lungs except at 6 h, whereas the combination of both antibiotics induced a significant decrease in the lung bacterial count 6, 12 and 24 h after the onset of therapy when compared with tissue bacterial numbers in untreated animals or animals treated with either antibiotic alone. In-vivo synergy between cefepime and amikacin was observed at the three time points studied. No resistant clones emerged during treatment with any of the antibiotic regimens studied.

Prospective, randomized trial of two antiseptic solutions for prevention of central venous or arterial catheter colonization and infection in intensive care unit patients

OBJECTIVES

To compare the efficacy of a newly available antiseptic solution (composed of 0.25% chlorhexidine gluconate, 0.025% benzalkonium chloride, and 4% benzyl alcohol), with 10% povidone iodine, on the prevention of central venous or arterial catheter colonization and infection.

DESIGN

Prospective, randomized clinical trial.

SETTING

Surgical-trauma intensive care unit (ICU) in a university hospital.

PATIENTS

All patients admitted to the ICU and requiring the insertion of a central venous and/or an arterial catheter from July 1, 1992 to October 31, 1993.

INTERVENTIONS

Patients were randomly assigned to one of two groups according to the antiseptic solution used for insertion and catheter care. The same solution was used for skin disinfection from the time of catheter insertion to the time of removal of each catheter.

MEASUREMENTS AND MAIN RESULTS

Catheter distal tips were quantitatively cultured when catheters were no longer necessary, if there was a suspicion of catheter-related infection, and routinely after 7 days of use for arterial catheters, or after 15 days of use for central venous catheters. The rate of significant catheter colonization (i.e., > or = 10(3) colony-forming units [cfu]/mL by quantitative culture), and catheter-related sepsis (as defined by sepsis abating following catheter removal per 1,000 catheter-days), were significantly lower in the chlorhexidine group (12 vs. 31 [relative risk 0.4, 95% confidence interval 0.1 to 0.9, p < .01] and 6 vs. 16 [relative risk 0.4, 95% confidence interval 0.1 to 1, p = 0.5], respectively). The rate of central venous catheter colonization and central venous catheter-related sepsis per 1,000 catheter-days were also significantly lower in the chlorhexidine group (8 vs. 31 [relative risk 0.3, 95% confidence interval 0.1 to 1, p = .03] and 5 vs. 19 [relative risk 0.3, 95% confidence interval 0.1 to 1, p = .02], respectively). Finally, the rate of arterial catheter colonization per 1,000 catheter-days was significantly lower in the chlorhexidine group (15 vs. 32 [relative risk 0.5, 95% confidence interval 0.1 to 1, p = .05]), whereas the rate of arterial catheter-related sepsis per 1,000 catheter-days was similar for the two study groups (8 in the chlorhexidine group vs. 10 in the povidone iodine group [relative risk 0.8, 95% confidence interval 0.1 to 2.2, p = .6]). The 0.25% chlorhexidine solution was superior to the 10% povidone iodine solution in preventing catheter colonizations and catheter-related sepsis due to Gram-positive bacteria (5 vs. 20 [p < .001], and 2 vs. 10 [p < .001], respectively), whereas the activity of the 0.25% chlorhexidine solution was nonsignificantly superior in preventing Gram-negative infections (7 vs. 4 [p = .5], and 4 vs. 2 [p = .8], respectively).

CONCLUSIONS

The 4% alcohol-based solution of 0.25% chlorhexidine gluconate and 0.025% benzalkonium chloride was more effective than 10% povidone iodine for insertion site care of short-term central venous and arterial catheters. This effect appeared related to a more efficacious prevention of infections with Gram-positive bacteria.

Use of the coagulase gene typing method for detection of carriers of methicillin-resistant Staphylococcus aureus

Strains of Staphylococcus aureus can be typed on the basis of the polymorphism of the coagulase gene. DNA fragments generated after amplification by polymerase chain reaction (PCR) of the variable region of this gene and digested with the restriction enzyme HaeIII can be compared by their restriction fragment length polymorphism (RFLP). Seventy-nine of 86 (91.8%) methicillin-resistant S. aureus (MRSA) strains isolated in various hospitals had a characteristic RFLP pattern. This pattern differed from those of 32 methicillin-susceptible S. aureus (MSSA). Only one MSSA shared with MRSA the same RFLP pattern. After modification, we applied this method to the rapid detection of MRSA from 255 nasal swabs from patients hospitalized in intensive care units. When screened by plating on Chapman agar, 55 of these samples contained MRSA, whereas 40/55 yielded the expected restriction profile after amplification by PCR. No DNA was amplified by PCR in 9/55 samples and restriction profiles were uninterpretable in six cases. When compared to culture, the positive and negative predictive values of the PCR test were 100% and 93%, respectively. The specificity was 100% and the sensitivity was 72.7%. Since control of spread of MRSA strains in hospitals is based in part on rapid isolation of carriers, this method which allows detection of epidemic MRSA in nasal swabs within a day could be helpful, though culture would still be necessary to confirm the result.

Influence of experimental rat model of multiple organ dysfunction on cefepime and amikacin pharmacokinetics

We adapted an experimental model of multiple organ dysfunction to study the alterations it induces in the pharmacology of cefepime and amikacin. The half-lives of both antibiotics were significantly prolonged because of nonsignificant enhancement of the volume of distribution and reduced renal elimination. In the presence of multiple organ dysfunction, the concentration of each antibiotic in the lungs, compared with that in the lungs of healthy controls, was significantly decreased, despite similar concentrations in plasma, indicating that the application of a standard antibiotic concentration in plasma could lead to underdosage in tissues during the initial days of therapy.

Transgastric, pulsed Doppler echocardiographic determination of cardiac output

OBJECTIVE

The aim of this study was to evaluate the accuracy of cardiac output measurement with transesophageal echocardiography (TEE) using a transgastric, pulsed Doppler method in acutely ill patients.

DESIGN

Cardiac output was simultaneously measured by thermodilution (TD) and a transgastric, pulsed Doppler method.

SETTING

The study was carried out in a surgical intensive care unit as part of the management protocol of the patients.

PATIENTS

Thirty consecutive acutely ill patients with a Swan-Ganz catheter, mechanically ventilated, sedated and with a stable hemodynamic condition were included.

MEASUREMENTS

Pulsed Doppler TEE was performed using a transgastric approach in order to obtain a long axis view of the left ventricle. Cardiac output was calculated from the left ventricular outflow tract diameter, the velocity time integral of the blood flow profile and heart rate.

RESULTS

One patient was excluded because of the presence of aortic regurgitation and another, because of the impossibility of obtaining a transgastric view. Twenty-eight simultaneous measurements were performed in 28 patients. A clinically acceptable correlation and agreement were found between the two methods (Doppler cardiac output = 0.889 thermodilution cardiac output +0.74 l/min, r = 0.975, p <0.0001).

CONCLUSION

Transgastric pulsed Doppler measurement across the left ventricular outflow tract with TEE is a very feasible and clinically acceptable method for cardiac output measurement in acutely ill patients.

Contribution of bronchoalveolar lavage to the diagnosis of posttraumatic pulmonary fat embolism

OBJECTIVE

To verify whether the determination of the percentage of cells recovered by bronchoalveolar lavage and containing fat inclusions is a useful diagnostic tool of posttraumatic pulmonary fat embolism.

DESIGN

Prospective study.

SETTING

Surgical Intensive Care Units in two university hospitals.

PATIENTS

56 successive trauma patients needing prolonged postinjury mechanical ventilation, including 4 with clinical definite fat embolism syndrome, 5 in whom the diagnosis had been clinically suspected but was impossible to confirm or exclude before bronchoscopy, and 47 with no clinical evidence of the syndrome. Control groups included 8 patients without previous trauma who developed ARDS and 6 healthy surgical patients.

METHODS

Bronchoalveolar lavage was performed within the first post-traumatic 3 days in trauma patients, at the beginning of the pulmonary disease in non trauma ARDS patients and just after anesthesic induction in healthy ortopedic patients. The magnitude of lipid content in alveolar cells was compared with the clinical pattern of the pulmonary fat embolism syndrome retrospectively evaluated at the seventh day postinjury in trauma patients.

RESULTS

All the patients with definite fat embolism syndrome had more than 70% of lavage cells containing fat droplets. The group of patients in whom the diagnosis of the fat embolism syndrome was suspected had percentages of fat cells above 30% in 4 out of 5 patients. A percentage of fat cells above 30% was only observed in 7 out of the 47 patients without clinical evidence of the syndrome. The percentage varied between 0% to 35% in the group of non trauma ARDS patients and between 0 to 5% in healthy surgical patients.

CONCLUSION

Lipid inclusions in alveolar cells are common during traumatic and non-traumatic respiratory failure. Determination of the percentage of cells recovered by bronchoalveolar lavage and containing fat droplets may contribute to the diagnosis of the fat embolism syndrome in mechanically-ventilated trauma patients with respiratory failure provided that the significant threshold would be 30%.

Limited usefulness of urinary dipsticks to screen out catheter-associated bacteriuria in ICU patients

The use of urinary dipsticks to screen out sterile urine specimens was investigated in catheterized ICU patients. During a three-month period, each urine sample quantitatively cultured was concurrently tested at the bedside with a dipstick. A total of 102 urine samples taken from 43 patients were analysed. Thirty-eight of them showed bacterial or yeast growths (incidence rate, 37%). The negative predictive value of the leukocyte esterase pad and/or the nitrate test pad to screen out sterile urine samples was 81%, indicating that dipsticks cannot routinely be proposed to select catheterized ICU patients for quantitative culture of urine.

Role of systemic inflammatory response syndrome and infection in the occurrence of early multiple organ dysfunction syndrome following severe trauma

OBJECTIVE

To evaluate the role of infection and systemic inflammatory response syndrome (SIRS) on the occurrence of early posttraumatic MODS.

DESIGN

Retrospective study.

SETTING

University Teaching Hospital ICU.

PATIENTS

163 consecutive patients hospitalized for more than 48 hours following severe trauma.

MEASUREMENTS AND MAIN RESULTS

The patients were classified into two groups in respect to the existence of MODS at day 2. There was 27 patients in the MODS group and 136 patients in the no MODS group. The two groups were similar with respect to age, sex ratio and Simplified Acute Physiology Score. The MODS group had a higher mortality (52 versus 7%), Injury Severity Score (45 +/- 14 versus 31 +/- 13), hypovolemic shock rate (74 versus 30%), massive volume replacement rate (59 versus 6%) and SIRS rate (81 versus 54%) than the no MODS group (P < 0.05). The rate of infection was similarly low in the MODS and no MODS group (4 versus 6% respectively).

CONCLUSION

Early MODS is often associated with hypotension and massive volume administration but very rarely with infection, despite the high rate of SIRS.

Pulmonary artery catheterization in critically ill patients: a prospective analysis of outcome changes associated with catheter-prompted changes in therapy

OBJECTIVE

To evaluate physician accuracy in predicting patients' hemodynamic profiles, associated morbidities, rates of change in therapy resulting from catheterization, and the outcome variations associated with such change before the insertion of a pulmonary artery catheter.

DESIGN

Prospective, descriptive, cohort study with no interventions.

SETTING

Medical intensive care unit (ICU) of a university hospital.

PATIENTS

One hundred twelve catheterizations performed in 112 patients without acute myocardial infarction. In 43 cases, catheterizations were indicated because of circulatory shock that was unresponsive to two standard therapeutic measures.

MEASUREMENTS AND MAIN RESULTS

Before catheterization, physicians were asked to predict the hemodynamic profile of the patients who were to be catheterized, and to provide a plan for therapy. After catheterization, each patient's chart was reviewed and compared with precatheterization predictions. Hemodynamic profiles were correctly predicted in only 56% of the cases. Information obtained from pulmonary artery catheters prompted changes in therapy in 58% of all cases and in 63% of patients in shock who were unresponsive to standard therapy. Modifications varied among hemodynamic profiles, from 33% (fluid overloaded) to 87% (hypovolemia). Complications occurred in 11 catheterizations, but only two complications required therapy (pneumothorax [n = 1] and one episode of arrhythmia). No systemic infection occurred, and all blood cultures sampled through catheters before the catheters were withdrawn were sterile. In the entire group of patients, those patients in whom catheterization induced a change in therapy and those patients in whom no change in therapy occurred had similar precatheterization characteristics and mortality rates. However, in the subgroup of patients in shock that was unresponsive to standard therapy, the mortality rate was significantly lower when the assessment of hemodynamic data led to a change in therapy (59% vs. 100%, p = .009), despite identical precatheterization characteristics.

CONCLUSIONS

Prompted by assessment of pulmonary artery catheter measurements in patients with circulatory shock who were unresponsive to standard therapeutic measures, a change in therapy for these patients was associated with an improved prognosis, independent of other variables influencing outcome.