Peripheral microcirculatory exploration during mechanical ventilation weaning.

BACKGROUND: Weaning from mechanical ventilation is a daily challenge in intensive care patients. Our objective was to explore microcirculatory perfusion during mechanical ventilation weaning and to evaluate its predictive value on the weaning outcome. METHODS: Prospective observational study. All consecutive patients, older than 18 years, under mechanical ventilation that met the criteria for weaning were enrolled. Patients underwent a T-piece Spontaneous Breath Trial (SBT) for 60 minutes and the usual clinical parameters were recorded every 5 minutes. Microcirculatory perfusion was evaluated using the mottling score and the Tissue Oxygen Saturation (StO2) measured by Near Infrared Spectroscopy technology on the thenar and knee area. RESULTS: Seventy-three patients were studied (age: 67±15 years, men: 40, SAPS II: 47±15) after a duration of mechanical ventilation of 3 (1-6) days. Forty-five patients succeeded the first SBT. The mottling score severity recorded just before ventilator disconnection (baseline) was associated with weaning failure (P=0.03). Moreover, the mottling score increase during SBT was significantly associated with weaning failure (80% vs. 28%, P=0.001; Odds ratio 10.5 [2.0-54.8]). Baseline thenar StO2 was not different according to weaning outcome (failure 76±13% vs. success 77±7%, P=0.90) whereas baseline knee StO2 was significantly lower in patients who failed the first SBT (67±13% vs. 75±12%, P<0.01). This difference was apparent since the very beginning of the SBT and lasted throughout the trial (P=0.0001). CONCLUSION: In unselected mechanically ventilated patients undergoing SBT, mottling score and knee StO2 are early predictors of weaning failure.

Knee area tissue oxygen saturation is predictive of 14-day mortality in septic shock.

PURPOSE: Thenar eminence tissue oxygen saturation (StO(2)) was developed to assess organ perfusion. However, mottling, a strong predictor of mortality in septic shock, develops preferentially around the knee. We aimed to evaluate the prognostic value of StO(2) measured around the knee in septic shock patients and compare it to thenar StO(2). METHODS: This was a prospective observational study in a tertiary teaching hospital. All consecutive patients with septic shock were included. Parameters were recorded when vasopressors were started (H0) and every 6 h during 24 h. Their predictive value was assessed on 14-day mortality. RESULTS: Fifty-two patients were included. SOFA score was 11 (9-15) and SAPS II was 56 (40-72). At 6 h after ICU admission (H6), mean arterial pressure, cardiac index, and central venous pressure were not different between non-survivors and survivors; but non-survivors had higher arterial lactate level (8.8 ± 5.0 vs. 2.2 ± 1.5 mmol/l, P < 0.001), lower urinary output (0.22 ± 0.45 vs. 0.70 ± 0.50 ml/kg/h, P < 0.001) and ScvO(2) (62 ± 20 vs. 72 ± 9 %, P = 0.03). At H6, StO(2) was lower in non-survivors; this difference was not significant for thenar StO(2) (70 ± 15 vs. 77 ± 12 %, P = 0.10) but was very pronounced for knee StO(2) (39 ± 23 vs. 71 ± 12 %, P < 0.001). At H6, a low knee StO(2) was associated with a higher mottling score (P < 0.01), a higher lactate level (P < 0.002, R (2) = 0.2), and a lower urinary output (P = 0.02, R (2) = 0.12). CONCLUSION: After initial septic shock resuscitation, StO(2) measured around the knee is a strong predictive factor of 14-day mortality.

Outcome of spontaneous and iatrogenic pneumothoraces managed with small-bore chest tubes.

BACKGROUND: Little is known about the efficacy of management of iatrogenic pneumothoraces with small-bore chest tubes. The aim of this study was to assess the outcome of iatrogenic pneumothoraces requiring drainage managed with a small-bore chest tube and to compare the results to spontaneous pneumothoraces treated in the same unit with the same device. The primary outcome was requirement of video-assisted thoracoscopic surgery for drainage failure; secondary outcomes were length of drainage and number of inserted chest tubes. METHODS: Patients with pneumothorax admitted between 1997 and 2007 were retrospectively identified. Traumatic pneumothoraces and those occurring under mechanical ventilation were excluded. All pneumothoraces were drained using the same small-bore chest tube (8 French) according to our local protocol. RESULTS: Five hundred sixty-one pneumothoraces were analysed, 431 (76.8%) were spontaneous pneumothoraces and 130 (23.2%) were iatrogenic. Iatrogenic pneumothoraces were associated with less requirement of video-assisted thoracoscopic surgery for drainage failure [adjusted odds ratio= 0.24 (0.04, 0.86)]. Length of drainage of iatrogenic pneumothoraces was longer than for primary spontaneous pneumothoraces (3.8 ± 3.1 vs. 2.7 ± 1.8 days, P < 0.001) and shorter than for secondary spontaneous pneumothoraces (4.6 ± 2.3 days, P = 0.004). Number of inserted chest tubes per patient was not significantly different according to pneumothoraces' aetiology. CONCLUSION: Small-bore chest tubes are feasible for treatment of iatrogenic pneumothoraces and have a better rate of success and slightly longer drainage duration than when used for spontaneous pneumothoraces.

Mottling score predicts survival in septic shock.

BACKGROUND: Experimental and clinical studies have identified a crucial role of microcirculation impairment in severe infections. We hypothesized that mottling, a sign of microcirculation alterations, was correlated to survival during septic shock. METHODS: We conducted a prospective observational study in a tertiary teaching hospital. All consecutive patients with septic shock were included during a 7-month period. After initial resuscitation, we recorded hemodynamic parameters and analyzed their predictive value on mortality. The mottling score (from 0 to 5), based on mottling area extension from the knees to the periphery, was very reproducible, with an excellent agreement between independent observers [kappa = 0.87, 95% CI (0.72-0.97)]. RESULTS: Sixty patients were included. The SOFA score was 11.5 (8.5-14.5), SAPS II was 59 (45-71) and the 14-day mortality rate 45% [95% CI (33-58)]. Six hours after inclusion, oliguria [OR 10.8 95% CI (2.9, 52.8), p = 0.001], arterial lactate level [<1.5 OR 1; between 1.5 and 3 OR 3.8 (0.7-29.5); >3 OR 9.6 (2.1-70.6), p = 0.01] and mottling score [score 0-1 OR 1; score 2-3 OR 16, 95% CI (4-81); score 4-5 OR 74, 95% CI (11-1,568), p < 0.0001] were strongly associated with 14-day mortality, whereas the mean arterial pressure, central venous pressure and cardiac index were not. The higher the mottling score was, the earlier death occurred (p < 0.0001). Patients whose mottling score decreased during the resuscitation period had a better prognosis (14-day mortality 77 vs. 12%, p = 0.0005). CONCLUSION: The mottling score is reproducible and easy to evaluate at the bedside. The mottling score as well as its variation during resuscitation is a strong predictor of 14-day survival in patients with septic shock.

The endothelium: physiological functions and role in microcirculatory failure during severe sepsis.

The endothelium is a highly dynamic cell layer that is involved in a multitude of physiological functions, including the control of vascular tone, the movement of cells and nutrients, the maintenance of blood fluidity and the growth of new vessels. During severe sepsis, the endothelium becomes proadhesive, procoagulant, antifibrinolytic and is characterized by alterations of vasomotor regulation. Most of these functions have been discovered using in vitro and animal models, but in vivo exploration of endothelium in patients remains difficult. New tools to analyze endothelial dysfunction at bedside have to be developed.

Haemodilution induced by hydroxyethyl starches 130/0.4 is similar in septic and non-septic patients.

BACKGROUND: Fluid therapy induces haemodilution related to plasma volume expansion. The aim of our study was to compare haemodilution after a single hydroxyethyl starches (HES) 130/0.4 infusion in two groups of patients, one with and one without sepsis. We hypothesized that a single HES challenge would induce similar sustained haemodilution in both groups. METHODS: In this prospective preliminary study, patients predicted to require a single further volume-expander infusion were included immediately before receiving 500 ml of 6% HES 130/0.4 over a 15-min period. No additional fluid was administered over the next 8 h. Haematocrit, and serum albumin and protein were determined immediately before HES infusion then after 1, 2, 3, 4, and 8 h. RESULTS: Twelve patients were included in each group. In both groups, all three haemodilution markers had significantly lower values after 1 h than at baseline. None of the values after 1 and 3 h differed significantly between the two groups. Neither did any of the other study variables show significant differences between the groups with and without sepsis. CONCLUSION: We found that a starch-based compound was as effective in inducing haemodilution in patients with sepsis as in controls without sepsis, suggesting that HES may remain within the intravascular space even in patients with sepsis. Haemodilution parameters such as haematocrit, serum albumin and serum protein are useful for assessing the duration of plasma volume expansion induced by fluid therapy in critically ill patients.

Hyponatremia, hypernatremia: a physiological approach.

Natremia belongs to the toolbox of the practicing intensivist. It is an indicator of the hydration status, which is an item that must be continuously monitored in critically ill patients. Hyponatremia is not rare (1% to 2% of hospitalised patients), and hypernatremia is about 10 times less frequent while hypernatremia always indicates hypertonicity, hyponatremia is not equivalent to hypotonicity. Diagnosis depends on the history, clinical examination and basic biochemical data. It should be kept in mind that obtaining urine samples is as important as plasma samples in this respect. The first step consists in confirming that hyponatremia is hypotonic. The second step is to assess the renal response to hypotonicity. Hypotonic hyponatremia will be considered in association with hypovolemia, euvolemia or hypervolemia. The constitution of a hyperosmolar state requires an inadequate water intake The main goal of the treatment is not to normalize numbers (they must always be checked first), but to treat symptoms. Tolerance must always be appreciated. The mathematical formulas proposed are of interest for a better understanding, but should not be followed strictly.

Optimizing fluoroquinolone utilization in a public hospital: a prospective study of educational intervention.

Fluoroquinolone (FQ) utilization should be optimized, with the aim of controlling both multidrug-resistant bacteria and costs. In the present study, the appropriateness of FQ prescriptions for urinary tract infections (UTIs) before and after an educational intervention was examined prospectively. FQ-prescribing physicians received oral and written guidelines between the two phases of the study. All patients admitted to Saint-Antoine University Hospital (Paris) and treated with FQs for UTIs during the study period were included. The main outcome measures of the appropriateness of FQ prescriptions were based on the principles of Antibiotic Utilization Review. The study involved 127 patients. The main prescribing errors before the intervention were wrong routes of administration and failure to take into account antibiotic susceptibility results. The rate of erroneous prescriptions fell by 74.4% after intervention. About 71% of the improvement can be attributed to the intervention (71.4%; 95% confidence interval, 39.3-86.8). The intervention had an overall positive impact on FQ prescription quality. The decrease in inappropriate prescriptions was due mainly to the use of antibiotic susceptibility results (23% vs. 11.5%, P<0.05) and better consideration of indications (18.9% vs. 3.8%; P<0.05). Future educational interventions will cover other indications and will take into account costs and local antimicrobial susceptibility patterns.

[Complications due to peripheral venous catheterization. Prospective study]. / Complications liées au cathétérisme veineux périphérique. Etude prospective.

OBJECTIVE: Peripheral venous catheter (PVC)-associated complications were prospectively evaluated in a 2 month-study performed in 3 different wards. METHODS: For each inserted PVC, the following complications were observed daily by an external investigator: tenderness, erythema, swelling or induration, palpable cord and purulence. PVC that were removed were systematically sent to the Microbiology department and analysed according to the semi-quantitative method described by Brun-Buisson et al. RESULTS: A total of 525 PVC (corresponding to 1,036 catheterisation-days) were included. Main clinical complications were erythema (22.1%), tenderness (21.9%), swelling or induration (20.9%), palpable cord (2.7%) and purulence (0.2%). Phlebitis, defined by 2 or more of the following signs: tenderness, erythema, swelling or induration and palpable cord, was observed in 22%. Catheter colonization (> or = 103 CFU/ml) occurred in 13%. Bacteria isolated from colonized catheters were coagulase-negative staphylococci (88.1%), Staphylococcus aureus (7.1%) and Candida sp. (4.8%). Multivariate risk factor analysis showed that age > or = 55 y. (OR = 3.16, p = 0.003), insertion on articulation site (OR = 2.94, p = 0.01) or in jugular vein (OR = 8.18, p = 0.01) and > 72 hour-catheterisation (OR = 4.74, p = 0.0003) were significantly associated with PVC colonization. Risk factors for phlebitis were skin lesions (OR = 1.88, p < 0.016), active infection unrelated to PVC (OR = 2.8, p = 0.001), "poor quality" peripheral vein (OR = 2.46, p < 0.02) and > 72 hour-catherisation (OR = 2.38, p = 0.009). CONCLUSION: Complications associated with peripheral venous catheters are frequent but remain benign. They could probably be reduced by a systematic change every 72-96 hours as recommended by different guidelines.

A monthly systematic bacteriological report improves accuracy of identification of hospital-acquired infections in an ICU.

A prospective cohort study with retrospective validation was initiated in order to assess whether a monthly bacteriological report improves the accuracy in detecting hospital-acquired infections (HAI). The setting was a 14-bed medical intensive care unit (ICU) in a 821 bed French university affiliated hospital. One thousand, six hundred and two patients were admitted during the two-year study period, the mean age was 58+/-19 years, the mean Simplified Acute Physiology Score 2 (SAPS 2) was 34+/-21, and ICU mortality was 14%. The microbiology laboratory sent monthly bacteriological reports of urine samples and central venous catheter (CVC) tips back to the intensive-care unit physician in charge of the HAI surveillance programme. This enabled a comparison to be made between prospectively and retrospectively diagnosed hospital-acquired urinary tract infections (HAUTI) and CVC-related infections (HACVCI), HAUTI were prospectively identified in 51 cases (incidence density=10.03/1,000 days) and 23 more cases were found after receiving the monthly bacteriological report (final HAUTI incidence density=14.6/1,000 days, P<0.05). HACVCI were prospectively recognized in 13 cases (incidence density=4/1,000 days) and eight more cases were discovered (final HACVCI incidence density=6.52/1,000 days,P >0.1). All retrospectively diagnosed HAI occurred during the last 48 h of the patients' ICU stay. We conclude that the routine HAI surveillance programme is reliable, except for the last 48 h in the ICU. The monthly bacteriological report improved the accuracy of the HAI reporting rate.

Severe accidental hypothermia treated in an ICU: prognosis and outcome.

STUDY OBJECTIVES: To assess the characteristics and outcomes of patients admitted to an ICU for severe accidental hypothermia, and to identify risk factors for mortality. METHODS: All consecutive patients admitted to an ICU between January 1, 1979, and July 31, 1998, with a temperature of < or = 32 degrees C were retrospectively analyzed. Rewarming was always conducted passively with survival blankets and conventional covers. Prognostic factors were studied by means of univariate analysis (Mann-Whitney U and chi(2) tests) and multivariate analysis (logistic regression). RESULTS: Forty-seven patients were enrolled (mean +/- SD age, 61.7 +/- 16 years). Five patients had a cardiac arrest before ICU admission. Patient characteristics at ICU admission were as follows: temperature, 28.8 +/- 2.5 degrees C; systolic BP, 85 +/- 23 mm Hg; heart rate, 60 +/- 24 beats/min; Glasgow Coma Scale, 10.4 +/- 3.7; and simplified acute physiology score (SAPS) II, 50.9 +/- 27. Mechanical ventilation was necessary in 23 cases, and 22 patients in shock received vasoactive drugs. The mean length of stay in the ICU was 6.7 +/- 9 days. Eighteen patients (38%) died, but ventricular arrhythmia was never the cause. Univariate analysis identified several prognostic factors (p < 0.05): age (57 +/- 16 years vs 69 +/- 14 years), systolic arterial BP (93 +/- 20 mm Hg vs 71 +/- 21 mm Hg), blood bicarbonate level (23.5 +/- 5.2 mmol/L vs 16.6 +/- 6.2 mmol/L), SAPS II score (35.3 +/- 19.5 vs 72 +/- 21), mechanical ventilation (34% vs 81%), vasopressor agents (42% vs 82%), rewarming time (11.5 +/- 7.2 h vs 17.2 +/- 7 h), and discovery of the patient at home (2.3% vs 54.5%). The initial temperature did not influence vital outcome (28.9 +/- 2.6 degrees C vs 28.6 +/- 2.2 degrees C). Only the use of vasoactive drugs (odds ratio, 9; 95% confidence interval, 1.6 to 50.1) was identified as a prognostic factor in the multivariate analysis. CONCLUSION: Severe accidental hypothermia is a rare cause of ICU admission in an urban area. Its mortality remains high, but there is no overmortality according to the SAPS II-derived prediction of death. Shock, requiring treatment with vasoactive drugs, is an independent risk factor for mortality, while initial core temperature is not. It remains to be determined whether aggressive rather than passive rewarming procedures are better.

Ultrasonic examination: an alternative to chest radiography after central venous catheter insertion?

We evaluated ultrasonic examination as a diagnostic tool for catheter misplacement and pneumothorax after central venous catheter insertion. Physicians in the intensive care unit (ICU) performed the ultrasonic examinations, and the results were compared with those of chest radiography. Eighty-five central venous catheters (70 subclavian and 15 internal jugular) were inserted into 81 patients; 10 misplacements and one pneumothorax occurred. Ultrasonic examination feasibility was 99.6%. The only pneumothorax and all misplacements except one were diagnosed by ultrasound. Taking into consideration misplacements and pneumothorax research, ultrasonic examination did not give any false positive results. The mean time of the entire ultrasonic examination was 6.8 +/- 3.5 min, whereas 80.3 +/- 66.7 min were needed for the radiography (p < 0.0001). This study has suggested that ultrasonic diagnosis of catheter misplacement and pneumothorax related to central venous catheterization is a rapid and accurate method that can be easily performed by ICU physicians.

Bedside detection of retained tracheobronchial secretions in patients receiving mechanical ventilation: is it time for tracheal suctioning?

OBJECTIVE: To identify parameters that indicate retained secretions and the need for tracheal suctioning (TS) in patients receiving mechanical ventilation (MV). DESIGN: Prospective observational study. SETTING: A 14-bed medical ICU in a 946-bed university hospital. PATIENTS: Sixty-six consecutive patients receiving MV. INTERVENTIONS: Two successive tracheal suctions, TS1 and TS2, performed at a 2-h interval as usual patient care. Retained secretions were considered significant if the volume of secretions removed by TS2 was > 0.5 mL. MEASUREMENTS AND RESULTS: Variations between TS1 and TS2 of pulse oximetric saturation (SpO(2)), peak inspiratory pressure (Ppeak), tidal volume (VT), and Ramsay score were compared between patients with TS2 < or = 0.5 mL (group 1; n = 27) and patients with TS2 > 0.5 mL (group 2; n = 39). The presence of a sawtooth pattern on flow-volume loop displayed on the monitor screen of the ventilator and of respiratory sounds heard over the trachea before TS2 were compared between the two groups. Variations of Ppeak, VT, SpO(2), and Ramsay score between TS1 and TS2 did not differ between the two groups. However, group 2 had a sawtooth pattern (82% vs 29.6%; p = 0.0001) and respiratory sounds (66.6% vs. 25.9%; p = 0. 001) more frequently than group 1 before TS2. For the sawtooth pattern, the likelihood ratio (LR) of a positive test was 2.70 and the LR of a negative test was 0.25, while for respiratory sounds it was 2.50 and 0.45, respectively. When the presence of a sawtooth pattern and of respiratory sounds was combined, the LR of a positive test rose to 14.7 and the LR of a negative test was 0.42. CONCLUSIONS: A sawtooth pattern and/or respiratory sounds over the trachea are good indicators of retained secretions in patients receiving MV and may indicate the need for TS. Conversely, the absence of a sawtooth pattern may rule out retained secretions.