Prognostic significance of central venous-to-arterial carbon dioxide difference during the first 24 hours of septic shock in patients with and without impaired cardiac function.

OBJECTIVE: To investigate the prognostic significance of central venous-to-arterial carbon dioxide difference (cv-art CO 2 gap) during septic shock in patients with and without impaired cardiac function. METHODS: We performed a prospective cohort study in 10 French intensive care units. Patients suffering from septic shock were assigned to the impaired cardiac function group ('cardiac group', n =123) if they had atrial fibrillation (AF) and/or left ventricular ejection fraction (LVEF) <50% at study entry and to the non-cardiac group ( n =240) otherwise. RESULTS: Central venous and arterial blood gases were sampled every 6 h during the first 24 h to calculate cv-art CO 2 gap. Patients in the cardiac group had a higher cv-art CO 2 gap [at study entry and 6 and 12 h (all P <0.02)] than the non-cardiac group. Patients in the cardiac group with a cv-art CO 2 gap >0.9 kPa at 12 h had a higher risk of day 28 mortality (hazard ratio=3.18; P =0.0049). Among the 59 patients in the cardiac group with mean arterial pressure (MAP) ≥65 mm Hg, central venous pressure (CVP) ≥8 mm Hg and central venous oxygen saturation (ScvO 2 ) ≥70% at 12 h, those with a high cv-art CO 2 gap (>0.9 kPa; n =19) had a higher day 28 mortality (37% vs. 13%; P =0.042). In the non-cardiac group, a high cv-art CO 2 gap was not linked to a higher risk of day 28 death, whatever the threshold value of the cv-art CO 2 gap. CONCLUSION: Patients with septic shock and with AF and/or low LVEF were more prone to a persistent high cv-art CO 2 gap, even when initial resuscitation succeeded in normalizing MAP, CVP, and ScvO 2 . In these patients, a persistent high cv-art CO 2 gap at 12 h was significantly associated with higher day 28 mortality.

Evaluation of pulse pressure variation validity criteria in critically ill patients: a prospective observational multicentre point-prevalence study.

BACKGROUND: Respiratory variation in pulse pressure (ΔPP) is commonly used to predict the fluid responsiveness of critically ill patients. However, some researchers have demonstrated that this measurement has several limitations. The present study was designed to evaluate the proportion of patients satisfying criteria for valid application of ΔPP at a given time-point. METHODS: A 1 day, prospective, observational, point-prevalence study was performed in 26 French intensive care units (ICUs). All patients hospitalized in the ICUs on the day of the study were included. The ΔPP validity criteria were recorded prospectively and defined as follows: (i) mechanical ventilation in the absence of spontaneous respiration; (ii) regular cardiac rhythm; (iii) tidal volume ≥8 ml kg(-1) of ideal body weight; (iv) a heart rate/respiratory rate ratio >3.6; (v) total respiratory system compliance ≥30 ml cm H2O(-1); and (vi) tricuspid annular peak systolic velocity ≥0.15 m s(-1). RESULTS: The study included 311 patients with a Simplified Acute Physiology Score II of 41 (39-43). Overall, only six (2%) patients satisfied all validity criteria. Of the 170 patients with an arterial line in place, only five (3%) satisfied the validity criteria. During the 24 h preceding the study time-point, fluid responsiveness was assessed for 79 patients. ΔPP had been used to assess fluid responsiveness in 15 of these cases (19%). CONCLUSIONS: A very low percentage of patients satisfied all criteria for valid use of ΔPP in the evaluation of fluid responsiveness. Physicians must consider limitations to the validity of ΔPP before using this variable.

Effect of intra-abdominal hypertension on left ventricular relaxation: a preliminary animal study.

BACKGROUND: In the intensive care unit, intra-abdominal hypertension (IAH) is a frequently encountered, life-threatening condition. The aim of this animal study was to evaluate the effect of IAH on left ventricular (LV) relaxation (i.e. the active phase of diastole). METHODS: Seven male rabbits were anaesthetized before mechanical ventilation. A 20 mm Hg increase in intra-abdominal pressure (IAP) was then induced by intraperitoneal infusion of 1.5% glycine solution. Haemodynamic parameters were recorded and the relaxation time constant tau (considered to be the best index of left ventricle relaxation) was calculated. All haemodynamic measurements were recorded at baseline and then after induction of IAH. RESULTS: A 20 mm Hg increase in IAP was not followed by a significant change in arterial pressure, but was associated with increases in central venous pressure (from 2 [-2 to 6] to 7 [-2 to 12] mm Hg, P= 0.03), LV end-diastolic pressure (from 7 [6-8] to 15 [11-19] mm Hg, P= 0.04) and the relaxation time constant tau (from 16 [14-18] to 43 [34-52] ms, P= 0.048). CONCLUSIONS: In this animal study, a 20 mm Hg increase in IAP impaired LV relaxation. Further studies are necessary to identify the causes of this impairment.

Snakebite on the hand: lessons from two clinical cases illustrating difficulties of surgical indication

Snakebite is a particularly important health problem in rural areas of tropical regions. A large number of victims survive with permanent physical sequelae due to local tissue necrosis. However, necrosis may be associated with compartment syndrome especially when the bite is on the hands or feet. Herein, we describe two cases reported at a rural district hospital in Central African Republic. The present study suggests that active multidisciplinary management may improve patient prognosis while evidencing how difficult it is to decide on surgical intervention.(AU)

[Severe overdose in vitamin K antagonist secondary to grapefruit juice absorption]. / Surdosage grave en antivitamine K secondaire à l'absorption de jus de pamplemousse.

Vitamin K antagonists (VKA) are very currently used. Nevertheless, they are known to interact with numerous drugs and foods. Grapefruit juice is known to interact with some drugs metabolized by the enterocytary cytochrome P450 3A4 but its interaction with drugs as VKA that have a good biodisponibility is not clearly demonstrated. We report here the case of a woman treated with VKA in whom massive absorption of grapefruit juice entailed an excessive VKA dosage and a severe haemorrhage.

Abdominal compartment syndrome and intraabdominal sepsis: two of the same kind?

BACKGROUND: Abdominal compartment syndrome and intra-abdominal hypertension are frequently associated with peritonitis. The aim of this study is to establish the relationship between intra-abdominal hypertension and intra-abdominal sepsis especially in critically ill patients. METHODS: Relevant information was identified through a Medline search (1966-October 2006). The terms used were "intra-abdominal sepsis", "peritonitis", "abdominal compartment syndrome", "intra-abdominal hypertension" and "relaparotomy for sepsis". The search was limited to English- and French-language publications. RESULTS: Only a few clinical trials exist on this specific topic. Further investigations are required to define the incidence of intra-abdominal hypertension in intra-abdominal sepsis, and the prognostic impact of this setting and finally the potential specific treatment. Abdominal compartment syndrome is more likely linked to the abdominal surgery than to peritonitis itself. CONCLUSION: Intra-abdominal pressure monitoring can be valuable in critically ill patients with suspicion of persisting intra-abdominal sepsis after surgical peritonitis treatment.

Cardiac ultrasound and abdominal compartment syndrome.

This review focuses on the available literature published about the evaluation of haemodynamic consequences of the abdominal compartment syndrome (ACS). Animal and clinical studies described decreased venous return, systemic vasoconstriction, systolic and diastolic dysfunction of left and right ventricles. Doppler echocardiography is a non-invasive bedside procedure which provides a complete haemodynamic evaluation of patients with ACS. Despite numerous evaluations in anesthesia during laparoscopic surgery, the use of echocardiography remains scarce in critically ill patients with ACS.

Abdominal compartment syndrome and intraabdominal sepsis: two of the same kind?

BACKGROUND: Abdominal compartment syndrome and intra-abdominal hypertension are frequently associated with peritonitis. The aim of this study is to establish the relationship between intra-abdominal hypertension and intra-abdominal sepsis especially in critically ill patients. METHODS: Relevant information was identified through a Medline search (1966-October 2006). The terms used were "intra-abdominal sepsis", "peritonitis", "abdominal compartment syndrome", "intra-abdominal hypertension" and "relaparotomy for sepsis". The search was limited to English- and French-language publications. RESULTS: Only a few clinical trials exist on this specific topic. Further investigations are required to define the incidence of intra-abdominal hypertension in intra-abdominal sepsis, and the prognostic impact of this setting and finally the potential specific treatment. Abdominal compartment syndrome is more likely linked to the abdominal surgery than to peritonitis itself. CONCLUSION: Intra-abdominal pressure monitoring can be valuable in critically ill patients with suspicion of persisting intra-abdominal sepsis after surgical peritonitis treatment.

Cardiac ultrasound and abdominal compartment syndrome.

This review focuses on the available literature published about the evaluation of haemodynamic consequences of the abdominal compartment syndrome (ACS). Animal and clinical studies described decreased venous return, systemic vasoconstriction, systolic and diastolic dysfunction of left and right ventricles. Doppler echocardiography is a non-invasive bedside procedure which provides a complete haemodynamic evaluation of patients with ACS. Despite numerous evaluations in anesthesia during laparoscopic surgery, the use of echocardiography remains scarce in critically ill patients with ACS.

Impact of elements containing glycopeptide resistance genes on expression of virulence in Enterococcus faecalis peritonitis: a pilot study with rats.

The relationship between virulence and chromosomal elements containing glycopeptide resistance genes was experimentally assessed for two transconjugant strains of Enterococcus faecalis (VanA and VanB phenotypes) and compared to that for a susceptible wild-type strain. Microbiologic and inflammatory effects were assessed in a polymicrobial rat model of peritonitis. Mean peritoneal enterococcus concentrations +/- standard deviations at day 1 were 2.1 +/- 1.9, 1.3 +/- 1.1, and 1.7 +/- 2.0 log(10) CFU/ml for susceptible, VanA, and VanB strains, respectively (P < 0.05). At day 3 also there were lower concentrations of glycopeptide-resistant enterococcal strains in peritoneal fluid (3.2 +/- 3.4, 1.8 +/- 1.8, and 2.1 +/- 2.4 log(10) CFU/ml for susceptible, VanA, and VanB strains, respectively [P < 0.05]). Transconjugant glycopeptide-resistant strains were associated with increased peritoneal cell counts at the different evaluation times of the experiment (P < 0.001). Plasma alpha1-acid glycoprotein concentrations were lower in the presence of the susceptible strain (667 +/- 189 mg/liter) than in the presence of the VanA or VanB strain (1,193 +/- 419 or 1,210 +/- 404 mg/liter, respectively [P < 0.05]), while concentrations of tumor necrosis factor alpha and interleukin-6 in peritoneal fluid remained similar for the strains. These results suggest a trend toward variation of virulence of transconjugant strains compared to the wild-type strain in this peritonitis model.

The deletion genotype of the angiotensin I-converting enzyme is associated with an increased vascular reactivity in vivo and in vitro.

OBJECTIVES: To define a link between the deletion genotype (DD) and vascular reactivity, we studied in vivo and in vitro phenylephrine (PE)-induced tone and the effect of angiotensin II (AII) at physiological (subthreshold) concentrations on PE-induced tone. BACKGROUND: The deletion allele (D) of the angiotensin I-converting enzyme (ACE) has been associated with a higher circulating and cellular ACE activity and possibly with some cardiovascular diseases. METHODS: During cardiac surgery PE-induced contraction was studied in patients with excessive hypotension. In parallel, excess material of internal mammary artery, isolated from patients operated for bypass surgery, was mounted in an organ chamber, in vitro, for isometric vascular wall force measurement. RESULTS: In patients under extracorporeal circulation, PE (25 to 150 microg) induced higher contractions in patients with the DD genotype (e.g., with PE 75 microg: 20.3 +/- 2.9 vs. 11.5 +/- 2.5 mm Hg/ml per min, DD vs. II/ID, n = 15 vs. 30, p < 0.03). In the mammary artery, in vitro, contractions to PE (0.1 to 100 micromol/liter) or AII (1 or 100 nmol/liter) were not affected by the genotype. Angiotensin II (10 pmol/liter) significantly potentiated PE (1 micromol/liter)-induced contraction in both groups. Potentiation of PE-induced tone by AII was significantly higher in the DD than in the II/ID group. CONCLUSIONS: The DD genotype was associated with an increased reactivity to PE in vivo and potentiating effect of exogenous AII in vitro. The higher response to PE in vivo might reflect a higher potentiation by endogenous AII. These data should be considered to understand possible link(s) between cardiovascular disorders and the ACE gene polymorphism.

G894T polymorphism in the endothelial nitric oxide synthase gene is associated with an enhanced vascular responsiveness to phenylephrine.

BACKGROUND: Differences in vascular reactivity to phenylephrine (PE) responsiveness have been largely evidenced in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). Because nitric oxide (NO) strongly affects modulation of the vascular tone in response to vasopressor agents, we hypothesized that the G894T polymorphism of the endothelial NO synthase gene (eNOS) could be related to changes in the pressor response to PE. METHODS AND RESULTS: The protocol was performed in 68 patients undergoing coronary artery bypass grafting (n=33) or valve surgery (n=35) in whom mean arterial pressure decreased below 65 mm Hg during normothermic CPB. Under constant and nonpulsatile pump flow conditions (2 to 2.4 L. min-1. m-2), a PE dose-response curve was generated by the cumulative injection of individual doses of PE (25 to 500 micrograms). The G894T polymorphism of the eNOS gene was determined, and 3 groups were defined according to genotype (TT, GT, and GG). Groups were similar with regard to perioperative characteristics. The PE dose-dependent response was significantly higher in the allele 894T carriers (TT and GT) than in the homozygote GG group (P=0.02), independently of possible confounding variables. CONCLUSIONS: These results evidenced an enhanced responsiveness to alpha-adrenergic stimulation in patients with the 894T allele in the eNOS gene.

Angiotensin II type 1 receptor gene polymorphism is associated with an increased vascular reactivity in the human mammary artery in vitro.

A gene polymorphism of the angiotensin II (AII) type 1 receptor has been described previously (A to C transversion at position 1166). Besides the epidemiological studies needed to determine a possible relationship between the polymorphism and some cardiovascular diseases, no study has been conducted to determine the impact of the polymorphism on vascular functions. At subthreshold concentrations, within the physiological range, AII potentiates alpha-adrenergic-dependent vascular tone. We investigated phenylephrine-induced tone and its amplification by AII (10 pmol/l) in human internal mammary artery rings mounted in organ baths. We performed concentration-response curves to phenylephrine (0.1-100 micromol/l) before and after pretreatment with AII (10 pmol/l). Patients had the genotype AA (n = 20) or the A to C transversion (AC/CC, n = 30). Contractions to phenylephrine (0.1-100 micromol/l) were significantly higher in rings from AC/CC than from AA patients (maximum response: 1.47+/-0.07 vs. 1.22+/-0.06 mN/mg, p < 0.001). AII (10 pmol/l) induced a significant potentiation of phenylephrine-induced contraction (e.g. 58.9% increase in tone with 1 micromol/l phenylephrine, p < 0.001) which was significantly lower in the AC/CC than in the AA group (46+/-9 vs. 66+/-7% with 1 micromol/l phenylephrine, p < 0.01). Contractions to AII (1 or 100 nmol/l) were not significantly affected by the genotype. Although the study was performed in arteries from patients with a coronary artery disease, these changes in vascular reactivity might be of interest in the understanding of the relationship between a possible higher probability of cardiovascular disorder and the genetic polymorphism of the AII type 1 receptor.