Decrease in pulse pressure and stroke volume variations after mini-fluid challenge accurately predicts fluid responsiveness†.

BACKGROUND: Dynamic indices, such as pulse pressure variation (PPV), are inaccurate predictors of fluid responsiveness in mechanically ventilated patients with low tidal volume. This study aimed to test whether changes in continuous cardiac index (CCI), PPV, and stroke volume variation (SVV) after a mini-fluid challenge (100 ml of fluid during 1 min) could predict fluid responsiveness in these patients. METHODS: We prospectively studied 49 critically ill, deeply sedated, and mechanically ventilated patients (tidal volume <8 ml kg(-1) of ideal body weight) without cardiac arrhythmias, in whom a fluid challenge was indicated because of circulatory failure. The CCI, SVV (PiCCO™; Pulsion), and PPV (MP70™; Philips) were measured before and after 100 ml of colloid infusion during 1 min, and then after the additional infusion of 400 ml during 14 min. Responders were defined as subjects with a ≥15% increase in cardiac index (transpulmonary thermodilution) after the full (500 ml) fluid challenge. Areas under the receiver operating characteristic curves (AUCs) and the grey zones were determined for changes in CCI (ΔCCI100), SVV (ΔSVV100), and PPV (ΔPPV100) after 100 ml fluid challenge. RESULTS: Twenty-two subjects were responders. The ΔCCI100 predicted fluid responsiveness with an AUC of 0.78. The grey zone was large and included 67% of subjects. The ΔSVV100 and ΔPPV100 predicted fluid responsiveness with AUCs of 0.91 and 0.92, respectively. Grey zones were small, including ≤12% of subjects for both indices. CONCLUSIONS: The ΔSVV100 and ΔPPV100 predict fluid responsiveness accurately and better than ΔCCI100 (PiCCO™; Pulsion) in patients with circulatory failure and ventilated with low volumes.

Mathematical coupling of data between global-end diastolic volume index and cardiac index calculated by the PiCCO device: myth or reality?

BACKGROUND: Aim of the study was to investigate whether cardiac index (CI) and global end diastolic volume index (GEDVi) determined from the same thermodilution curve are mathematically coupled during the infusion of an inotropic agent in critically ill patients. METHODS: Seventeen patients were prospectively studied. CI and GEDVi were evaluated in triplicate by the transpulmonary thermodilution technique with the PiCCO system before and 20 to 30 minutes after increases in dobutamine infusion rate. Mixed linear model was used to determine the within-subject correlation coefficient between changes in CI and GEDVi induced by changes in dobutamine infusion rate. RESULTS: Dobutamine administration significantly increased CI by 48±35%, whereas the average increase in GEDVi was only 8.2±12.3% but statistically significant (P<0.0001). The increase of GEDVi in response to dobutamine infusion was unexpected given that dobutamine has no recognized effect on right and left ventricular dimensions. Intriguingly, we observed a significant correlation coefficient, in individual patients, between changes in CI and GEDVi (r=0.58, P=0.002). CONCLUSION: Our study provides evidence that changes in GEDVi are mathematically coupled to changes in CI during dobutamine infusion. Therefore, clinicians using PiCCO device to evaluate GEDVi must be aware of the underlying formula to avoid placing undue reliance on artifactual correlations due to mathematical coupling.

Epidemiological features and prognosis of severe community-acquired pneumococcal pneumonia.

OBJECTIVE: To describe risk factors of severe pneumococcal community-acquired pneumonia and to study variables influencing outcome. DESIGN: Retrospective (1987-1992) and prospective (1993-1995) study. SETTING: Three participating ICUs from primary care hospitals. PATIENTS: Five hundred and five patients (mean age: 63 +/- 17 years) with severe community-acquired pneumonia (CAP). Three groups of patients were defined: pneumococcal CAP (group 1), CAP with microbial diagnosis other than Streptococcus pneumoniae (group 2), CAP from group 2 and CAP without microbial diagnosis (group 3). MEASUREMENTS AND RESULTS: Admission data and data on the disease's course were recorded. The mean Simplified Acute Physiologic Score (SAPS) was 12.5 +/- 5.4. On admission 288 (57 %) patients were mechanically ventilated (mv) and 82 (16.2 %) required inotropic support. A microbial diagnosis was established for 309 (61.2%) patients. S. pneumoniae was isolated in 137 (27.1%) patients. Severe pneumococcal CAP was independently associated with male sex (p = 0.01), lack of antibiotics use before admission (p = 0.0001), non-aspiration pneumonia (p = 0.01) and septic shock (p = 0.0001). The overall mortality rate was 27.5 % (29.2 % in group 1). In patients with severe pneumococcal CAP, multivariate analysis showed that leukopenia less than 3,500/mm3 (p = 0.0004), age over 65 years (p = 0.01), septic shock (p = 0.01), sepsis related complications (p = 0.0001), ICU complications (p = 0.001) and inadequacy of antimicrobial therapy (p = 0.002) worsened the prognosis. CONCLUSIONS: Few features facilitate the identification of pneumococcal CAP on ICU admission. The prognosis is mostly related to severity of illness (leukopenia, septic shock) while comorbidities do not seem to influence outcome. Sepsis-related disorders, ICU complications and adequate antimicrobial chemotherapy are the major variables affecting the outcome during an ICU stay.

[Retrograde percutaneous catheterization of the internal jugular vein in head injured patients]. / Cathétérisme percutané rétrograde de la veine jugulaire interne chez les traumatisés crâniens.

The monitoring of jugular venous oxygen saturation and lactate concentration in order to detect cerebral ischaemia or hyperaemia requires the insertion of a fibreoptic catheter into the upper bulb of the internal jugular vein. With dissection studies we have defined superficial anatomical landmarks which are constant and easily palpable, namely the mastoid process and the sternocleidomastoid muscle. This technique does not require a rotation of the head. The puncture site is located at the top of a triangular area between its sternal and clavicular insertions. At this site the jugular vein is rather superficial. This study reports our experience of the retrograde catheterisation of the jugular vein in twelve severely head injured patients.