BackgroundEsophageal pressure (Pes) can provide information to guide mechanical ventilation in acute respiratory failure. However, both relative changes and absolute values of Pes can be affected by inappropriate filling of the esophageal balloon and by the elastance of the esophagus wall. We evaluated the feasibility and effectiveness of a calibration procedure consisting in optimization of balloon filling and subtraction of the pressure generated by the esophagus wall (Pew).MethodsAn esophageal balloon was progressively filled in 36 patients under controlled mechanical ventilation. VBEST was the filling volume associated with the largest tidal increase of Pes. Esophageal wall elastance was quantified and Pew was computed at each filling volume. Different filling strategies were compared by performing a validation occlusion test.ResultsFifty series of measurements were performed. VBEST was 3.5 ± 1.9 ml (range 0.5–6.0). Esophagus elastance was 1.1 ± 0.5 cmH2O/ml (0.3–3.1). Both Pew and the result of the occlusion test differed among filling strategies. At filling volumes of 0.5, VBEST and 4.0 ml respectively, Pew was 0.0 ± 0.1, 2.0 ± 1.9, and 3.0 ± 1.7 cmH2O (p < 0.0001), whereas the occlusion test was satisfactory in 22 %, 98 %, and 88 % of cases (p < 0.0001).ConclusionsUnder mechanical ventilation, an increase of balloon filling above the conventionally recommended low volumes warrants complete transmission of Pes swings, but is associated with significant elevation of baseline. A simple calibration procedure allows finding the filling volume associated with the best transmission of tidal Pes change and subtracting the associated baseline artifact, thus making measurement of absolute values of Pes reliable.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-016-1278-5) contains supplementary material, which is available to authorized users.

Lung ultrasound gained a leading position in the last year as an imaging technique for the assessment and management of patients with acute respiratory failure. In coronavirus disease 2019 (COVID-19), its role may be of further importance because it is performed bedside and may limit chest X-ray and the need for transport to radiology for computed tomography (CT) scan. Since February 21, we progressively turned into a coronavirus-dedicated intensive care unit and applied an ultrasound-based approach to avoid traditional imaging and limit contamination as much as possible. We performed a complete daily examination with lung ultrasound score computation and systematic search of complications (pneumothorax, ventilator-associated pneumonia); on-duty physicians were free to perform CT or chest X-ray when deemed indicated. We compared conventional imaging exams performed in the first 4 wk of the COVID-19 epidemic with those in the same time frame in 2019: there were 84 patients in 2020 and 112 in 2019; 64 and 22 (76.2% vs. 19.6%, p < 0.001) had acute respiratory failure, respectively, of which 55 (85.9%) were COVID-19 in 2020. When COVID-19 patients in 2020 were compared with acute respiratory failure patients in 2019, the median number of chest X-rays was 1.0 (1.0À2.0) versus 3.0 (1.0À4.0) (p = 0.0098); 2 patients 2 (3.6%) versus 7 patients (31.8%) had undergone at least one thoracic CT scan (p = 0.001). A self-imposed ultrasound-based approach reduces the number of chest X-rays and thoracic CT scans in COVID-19 patients compared with patients with standard acute respiratory failure, thus reducing the number of health care providers exposed to possible contamination and sparing personal protective equipment.

We have studied the efficacy of a continuous paravertebral infusion of bupivacaine for the management of post-thoracotomy pain in 20 infants with a median age of 5.3 weeks (range 2 days to 20 weeks). Immediately before chest closure, 0.25% bupivacaine 1.25 mg kg-1 was injected into an extrapleural paravertebral catheter, inserted under direct vision. A continuous infusion of 0.25% bupivacaine 0.5 mg kg-1 h-1 was commenced 1 h later and terminated after 24 h. We found that extrapleural paravertebral catheter placement under direct vision was easy in neonates and infants. The technique provided effective postoperative pain relief in 18 (90%) patients and the failure in two (10%) infants was attributed to catheter block. Mean maximum serum concentrations of bupivacaine after the loading dose and during infusion were 1.03 (SD 0.56) and 2.00 (0.63) microgram ml-1, respectively. There were no major complications relating to the technique and we conclude that extrapleural paravertebral block is a simple and effective method for post-thoracotomy analgesia in young infants.

IF 12.015Lettre à l'éditeur ("Intensive Care Medicine", 2017)https://link.springer.com/article/10.1007%2Fs00134-017-4941-