Prognosis factors and outcome of community-acquired pneumonia needing mechanical ventilation

PURPOSE: To evaluate the variables associated with mortality of patients with community-acquired pneumonia who require mechanical ventilation and to determine the attributable morbidity and intensive care unit (ICU) mortality of community-acquired pneumonia. MATERIAL AND METHODS: Retrospective cohort study carried out in 361 ICUs from 20 countries including 124 patients who required mechanical ventilation on the first day of admission to the hospital due to acute respiratory failure secondary to severe community-acquired pneumonia. To assess the factors associated with outcome, a forward stepwise logistic regression analysis was performed, and to determine the attributable mortality of community-acquired pneumonia, a matched study design was used. RESULTS: We found 3 independent variables significantly associated with death in patients with community-acquired pneumonia requiring mechanical ventilation: simplified acute physiological score greater than 45 (odds ratio, 5.5 [95% confidence interval, 1.7-12.3]), shock (odds ratio, 5.7 [95% confidence interval, 1.7-10.1]), and acute renal failure (odds ratio, 3.0 [95% confidence interval, 1.1-4.0]). There was no statistically significant difference in ICU mortality among patients with or without community-acquired pneumonia (32% vs 35%; P=.59). CONCLUSIONS: Community-acquired pneumonia needing mechanical ventilation is not a disease associated with higher mortality. The main determinants of patient outcome were initial severity of illness and the development of shock and/or acute renal failure.     

Antibiotic levels in bronchial tree and in serum during selective digestive decontamination

Selective digestive decontamination has been found to prevent pulmonary infections in mechanically ventilated patients. The aims of this study were: 1) to determine whether detectable levels of antibiotics could be found in bronchial tree secretions of patients receiving SDD, and 2) to evaluate antibiotic serum levels. In 15 patients receiving mechanical ventilation and SDD for 10 days or more, tobramycin and amphotericin B levels were determined every 3 days in the following specimems: tracheal aspirates, distal bronchial secretions and blood samples. 82% of tracheal aspirates contained detectable (>0.18 mg/l), tobramycin concentrations; the levels varied widely between patients and large day-to-day variations were observed. Every patient had at least 1 tracheal aspirate with tobramycin level higher than 0.5 mg/l during his course. 40% of distal specimens contained detectable tobramycin levels (10 patients). Serum determinations showed detectable concentration of tobramycin in 50% of the specimens (9 patients). Two patients with renal failure had serum tobramycin levels higher than 2 mg/l. In 13 tracheal aspirates cultures were positive and 15 species were isolated; 13 had a MIC higher than the corresponding tobramycin level in tracheal secretions. We conclude than substantial levels of antibiotics can be found frequently in respiratory tract specimens of patients receiving SDD. Therefore, the usual microbiological criteria used to assess respiratory tract infection may be unreliable in this setting and other criteria may be required. Follow-up of antibiotic serum levels is required, especially in patients with renal failure.     

PEEP ventilation does not cause humorally mediated cardiac output depression in pigs

Objective This study was designed to see if humorally mediated negative inotropism contributes to the cardiac output (CO) depression seen during positive endexpiratory pressure (PEEP) ventilation.Design 8 pairs of piglets were used and a combined blood circulation was established between the two animals in each pair. One animal was ventilated with a PEEP of 15 cmH₂O (donor) and the other was ventilated without PEEP (recipient).Measurement and results CO and stroke volume deteriorated in the donors by 32% and 44%, respectively, while no change was seen in the recipients.Conclusion As humorally mediated negative inotropism during PEEP ventilation has earlier been demonstrated in dogs, the results suggest that this mechanism might be species-dependent.     

Septal Flash-like Motion of the Earlier Activated Ventricular Wall Represents the Pathophysiology of Mechanical Dyssynchrony in Single-Ventricle Anatomy

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Volume-targeted modes of modern neonatal ventilators: how stable is the delivered tidal volume?

Objective Volume-targeted modes are designed to deliver a constant tidal volume (V_t) at lowest possible pressure independently of changes in compliance, resistance, and leak of the respiratory system. We examined whether these volume-targeted modes respond rapidly enough to sudden changes in respiratory mechanics (e.g., selective intubation, surfactant administration, endotracheal tube kinking, de-kinking, obstruction), resulting in insufficient or excessive V_t delivery. Design and setting Bench study of six neonatal ventilators in the volume-targeted mode simulating preterm and full-term infant settings on a test lung. Measurements and results Breath-to-breath expiratory V_t were measured after rapid compliance, resistance, and leak changes. Under our test settings all ventilators showed important volume overshooting following rapid increase in compliance or decrease in resistance. Between one and 16 inflations were required to return to the set V_t. Some ventilators delivered inaccurate V_t under steady state condition while others showed considerable breath-to-breath V_t variability. Conclusions We observed inaccurate V_t delivery under specific conditions as well as immediate and sometimes prolonged volume overshooting after a rapid respiratory system compliance increase or resistance decrease in volume-targeted modes of modern neonatal ventilators. Similar discrepancies between the set V_t and the delivered inflations can be harmful in clinical situations, especially in newborns. Their clinical relevance needs to be clarified with safety studies in the neonatal population and we encourage manufacturers to further improve the ventilators algorithms. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

The role of uninjured nerve in spinal nerve ligated rats points to an improved animal model of neuropathic pain.

L5 and L6 spinal nerve ligation (SNL) in rats leads to behavioral signs of neuropathic pain including mechanical allodynia. The purposes of this study were to investigate the role of the intact L4 spinal nerve in the development of mechanical allodynia following L5 and L6 SNL and, as a result, to develop a modified model of neuropathic pain. As a first set of experiments, in addition to tight ligation of the left L5 and L6 spinal nerves, the intact L4 spinal nerve was manipulated either (1) by gentle repeated stretching of the L4 spinal nerve immediately after L5 and L6 SNL or (2) by intermittent mechanical stimulation to the ipsilateral paw during the first week after SNL. Tactile sensitivity was measured by determining the foot withdrawal threshold before and after SNL. Mild irritation of L4 spinal nerve and application of mechanical stimuli to the ipsilateral paw significantly increased the development of mechanical allodynia after SNL. In a second set of experiments, SNL was produced by tightly ligating only the left L5 spinal nerve with or without a loop of 5-0 chromic gut placed loosely around the L4 spinal nerve. This additional L4 loop significantly increased long-lasting tactile sensitivity compared to L5 SNL alone. These results suggest that afferent activity of the intact L4 spinal nerve aids in the development of mechanical allodynia in the SNL model of neuropathic pain. The addition of a chromic gut loop around the intact L4 spinal nerve can augment the development of mechanical allodynia following SNL of L5. We propose this latter as a useful and practical animal model of neuropathic pain.     

Recombinant streptokinase vs hydrocortisone suppositories in acute hemorrhoids: A randomized controlled trial

AIM: To compare the efficacy and safety of recombinant streptokinase(rSK) vs hydrocortisone acetate-based suppositories in acute hemorrhoidal disease.METHODS: A multicenter(11 sites), randomized(1:1:1), open, controlled trial with parallel groups was performed. All participating patients gave their written,informed consent. After inclusion, patients with acute symptoms of hemorrhoids were centrally randomized to receive, as outpatients, by the rectal route, suppositories of rSK 200000 IU of one unit every 8 h(first 3 units)and afterwards every 12 h until 8 administrations were completed(schedule A), one unit every 8 h until 6 units were completed(schedule B), or 25 mg hydrocortisone acetate once every 8 h up to a maximum of 24 administrations. Evaluations were performed at 3, 5,and 10 d post-inclusion. The main end-point was the 5thday response(disappearance of pain and bleeding, and≥ 70% reduction of the lesion size). Time to response and need for thrombectomy were secondary efficacy variables. Adverse events were also evaluated.RESULTS: Groups were homogeneous with regards to demographic and baseline characteristics. Fifth day complete response rates were 156/170(91.8%; 95%CI:87.3-96.2), 155/170(91.2%; 95%CI: 86.6%-95.7%),and 46/170(27.1%; 95%CI: 20.1%-34.0%) with rSK(schedule A and B) and hydrocortisone acetate suppositories, respectively. These 64.6% and 63.9%differences(95%CI: 56.7%-72.2% and 55.7%-72.0%)were highly significant(P 0.001). This advantage was detected since the early 3rd day evaluation(68.8% and64.1% vs 7.1% for the rSK and active control groups,respectively; P 0.001) and was maintained even at the late 10 th day assessment(97.1% and 93.5% vs67.1% for rSK and hydrocortisone acetate, respectively;P 0.001). Time to response was 3 d(95%CI: 2.9-3.1)for both rSK groups and 10 d(95%CI: 9.3-10.7) in the hydrocortisone acetate group. This difference was highly significant(P 0.001). All subgroup stratified analyses(with or without thrombosis and hemorrhoid classification) showed a statistically significant advantage for the rSK groups. Thrombectomy was necessary in4/251 and 14/133 patients with baseline thrombosis in the rSK and hydrocortisone acetate groups, respectively(P 0.001). There were no adverse events attributable to the experimental treatment.CONCLUSION: rSK suppositories showed a significant advantage over a widely-used over-the-counter hydrocortisone acetate preparation for the treatment of acute hemorrhoidal illness, as well as having an adequate safety profile.