Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

BACKGROUND

Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation.

METHODS

WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109.

FINDINGS

Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0-4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2-6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital.

INTERPRETATION

In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates.

FUNDING

European Society of Intensive Care Medicine, European Respiratory Society.

Ligand-stabilized CdSe nanoplatelet hybrid structures with tailored geometric and electronic properties. New insights from theory

A theoretical protocol for the investigation of the properties of CdSe zinc blende nanoplatelets with different thicknesses in the (100) direction and stabilized by various ligands is proposed and validated with respect to experimental data.

A long-term clinical evaluation of autoflow during assist-controlled ventilation: a randomized controlled trial

BACKGROUND

Many new mechanical ventilation modes are proposed without any clinical evaluation. "Dual-controlled" modes, such as AutoFlow™, are supposed to improve patient- ventilator interfacing and could lead to fewer alarms. We performed a long-term clinical evaluation of the efficacy and safety of AutoFlow during assist-controlled ventilation, focusing on ventilator alarms.

METHODS

Forty-two adult patients, receiving mechanical ventilation for more than 2 days with a Dräger Evita 4 ventilator were randomized to conventional (n = 21) or AutoFlow (n = 21) assist-controlled ventilation. Sedation was given using a nurse-driven protocol. Ventilator-generated alarms were exhaustively recorded from the ventilator logbook with a computer. Daily blood gases and ventilation outcome were recorded.

RESULTS

A total of 403 days of mechanical ventilation were studied and 45,022 alarms were recorded over a period of 8074 hours. The course of respiratory rate, minute ventilation, Fio(2), positive end-expiratory pressure, Pao(2)/Fio(2), Paco(2), and pH and doses and duration of sedation did not differ between the 2 groups. Outcome (duration of mechanical ventilation, ventilator-associated pneumonia, course of Sequential Organ Failure Assessment score, or death) was not different between the 2 groups. The number of alarms per hour was lower with AutoFlow assist-controlled ventilation: 3.3 [1.5 to 17] versus 9.1 [5 to 19], P < 0.0001 (median [quartile range]). In multivariate analysis, a low alarm rate was associated with activation of AutoFlow and a higher midazolam dose.

CONCLUSIONS

This first long-term clinical evaluation of the AutoFlow mode demonstrated its safety with regard to gas exchange and patient outcome. AutoFlow also allowed a very marked reduction in the number of ventilator alarms.

Epidural analgesia in a child with sickle cell disease complicated by acute abdominal pain and priapism

We describe a case of a 9-yr-old child with sickle cell disease complicated by abdominal vaso-occlusive crisis and priapism. Both complications were successfully treated with a combination of epidural local anesthetics and morphine.

[Primary cardiac sarcoma treated by orthoptic cardiac transplantation. Apropos of a case]

The authors report a new case of cardiac sarcoma treated by cardiac transplantation. This treatment has been proposed for these malignant tumours of poor prognosis when simple excision is impossible, with variable results. This patient is in good general condition 20 months after transplantation. Transplantation is a therapeutic procedure which should be considered in malignant tumours limited to the heart.

Basaloid bronchial carcinoma. A histologic group with a poor prognosis

BACKGROUND

Basal cell carcinomas (BCCs) have been described in various locations, such as skin, anal canal, tongue, larynx, and recently, the lungs. These tumors seem to have a poor prognosis.

METHODS

A series of 115 surgically resected lung tumors, previously classified as poorly or undifferentiated carcinoma, were reviewed retrospectively. From these, 37 cases were reclassified as BCCs and were compared in terms of clinical features and survival, with 40 cases reclassified as poorly differentiated squamous cell (PDSC) carcinoma of the lung.

RESULTS

There was no difference between the groups regarding age, clinical presentation, pattern of relapse, and cause of death. Median and overall survival were different between the two groups, especially for Stage I and II patients: 5-year actuarial survival in the BCC group was 15% and in the PDSC group 47% (P = 0.004).

CONCLUSIONS

This subset of non-small cell lung cancer (NSCLC) has a worse prognosis than other NSCLC, and this should be considered in survival studies and new treatment trials.

Cutaneous lesion associated with multiple endocrine neoplasia type 2A: lichen amyloidosis or notalgia paresthetica?

Three patients of a French family demonstrated an association of multiple endocrine neoplasia type 2A (MEN 2A) with a pruritic scapular skin lesion. The lesions are similar to those described as familial cutaneous lichen amyloidosis in unrelated MEN 2A and medullary thyroid carcinoma families, but histological, immunohistochemical, and ultrastructural analysis of skin biopsies from each patient in the French family did not show amyloid deposition. The topography of the lesion follows dermatomes C8-D3. The patients report not only pruritus but also paresthesia and hyperalgesia, and one showed touch hypoesthesia and pain hyperesthesia in the area of the lesion. Such an association of cutaneous and neurological features suggests notalgia paresthetica (NP), a neuropathy of the posterior dorsal rami nerves. We thus suggest that the cutaneous lesions associated with MEN 2A might be secondary to pathology in the neural crest-derived dorsal sensory nerves. The amyloid, when present, would be secondary to scratching. We propose that patients presenting with familial NP be suspect for MEN 2A.

Acromegaly due to a growth hormone-releasing hormone-secreting bronchial carcinoid tumor: further information on the abnormal responsiveness of the somatotroph cells and their recovery after successful treatment

We studied GH secretion in a patient with acromegaly and a bronchial carcinoid tumor before and again after surgical removal of this tumor. Before removal of the carcinoid tumor, plasma GH increased slightly after glucose loading (OGTT) and markedly after TRH (650%) and insulin (440%) treatment. Plasma GH did not change after GH-releasing hormone (GHRH), LHRH, or L-dopa administration. Somatostatin (SRIH) infusion lowered plasma GH. No change in plasma immunoreactive GHRH (IR-GHRH) occurred after TRH, glucose, insulin, or SRIH administration. Two weeks after removal of the carcinoid tumor, TRH induced GH secretion (250%) when the IR-GHRH level was undetectable and somatomedin-C was within normal limits. Fifteen weeks after surgery, the patient had normal GH secretion.

IN CONCLUSION

no pattern of GH secretion is diagnostic of acromegaly due to ectopic GHRH secretion, but the lack of GH response to exogenous GHRH and a large response during hypoglycemia may be features of this condition. When acromegaly and abnormal GH responsiveness are induced by a GHRH-secreting tumor, the increases in plasma GH after TRH, glucose, and insulin administration are not mediated by GHRH. After removal of the GHRH-secreting tumor, persistent paradoxical GH response to TRH does not require abnormally high IR-GHRH levels and does not preclude complete recovery.

What's new in light and electron microscopic immunocytochemistry? Application of the protein A-gold technique to routinely processed tissue

The protein A-gold technique, a simple and reliable two-step postembedding immunocytochemical method, allows the light and electron microscopic detection of antigens in routinely fixed and embedded tissue. At the light microscopic level a permanent, nonfading stain is obtained. High resolution studies on intracellular antigens can be performed since the particulate nature of the colloidal gold permits accurate determination of the labeled cellular structures. The applicability of the protein A-gold technique for the localization of various peptide and protein antigens by light and electron microscopy is demonstrated.