Interobserver agreement rate of the spontaneous breathing trial

Purpose

During the mechanical ventilation weaning process, the spontaneous breathing trial (SBT) is the confirmatory test of patients' capability to breathe unassisted. However, the SBT interobserver agreement rate (its reliability) is unknown, and our objective was to evaluate it.

Materials and Methods

This is a prospective, multicentric and observational study. Patients were included when the SBT criteria were fulfilled. Two physicians and 2 respiratory therapists (RTs) rated each SBT. The SBT interobserver agreement was measured using κ statistic and also the percentage of agreement with its 95% credible interval (CrI) calculated by a Bayesian inference.

Results

Ninety-three distinct physicians and 91 distinct RTs rated 130 SBTs. The κ coefficient was 0.46 for physicians and 0.57 for RT, indicating a moderate interobserver agreement rate. The percentage of agreement was 87.7% between physicians (95% CrI, 81.0%-92.3%) and 86.2% between RT (95% CrI, 79.2%-91.1%). The physicians' and RT' percentage of agreement were not statistically different (P = .71).

Conclusions

The SBT interobserver agreement rate is only moderate for physicians and RT. The percentage of agreement between 2 different SBT observers is 79.2% to 92.3%. Therefore, a relevant percentage of patients will have different extubation decisions depending on the SBT observer.     

Neonatal treatment with 192 IgG-saporin produces long-term forebrain cholinergic deficits and reduces dendritic branching and spine density of neocortical pyramidal neurons

The role of basal forebrain-derived cholinergic afferents in the development of neocortex was studied in postnatal rats. Newborn rat pups received intraventricular injections of 192 IgG-saporin. Following survival periods ranging from 2 days to 6 months, the brains were processed to document the cholinergic lesion and to examine morphological consequences. Immunocytochemistry for choline acetyltransferase (ChAT) and in situ hybridization for ChAT mRNA demonstrate a loss of approximately 75% of the cholinergic neurons in the medial septum and nucleus of the diagonal band of Broca in the basal forebrain. In situ hybridization for glutamic acid decarboxylase mRNA reveals no loss of basal forebrain GABAergic neurons. Acetylcholinesterase histochemistry demonstrates a marked reduction of the cholinergic axons in neocortex. Cholinergic axons are reduced throughout the cortical layers; this reduction is more marked in medial than in lateral cortical areas. The thickness of neocortex is reduced by approximately 10%. Retrograde labeling of layer V cortico-collicular pyramidal cells reveals a reduction in cell body size and also a reduction in numbers of branches of apical dendrites. Spine densities on apical dendrites are reduced by approximately 20-25% in 192 IgG- saporin-treated cases; no change was detected in number of spines on basal dendrites. These results indicate a developmental or maintenance role for cholinergic afferents to cerebral cortical neurons.      

Neofissure after right upper lobectomy: radiographic evaluation

Following lobectomy of the right upper lobe of the lung, a single fissure, the neofissure, separates the right middle and lower lobes. In 25 patients in whom chest radiographs and computed tomographic (CT) scans were obtained after right upper lobectomy, the neofissure was identifiable to some extent on the radiographs in seven (28%) and on CT scans in 24 (96%). Among those patients in whom the neofissure was seen in its entirety, in 12 of 20 (60%) it was oriented predominantly in the coronal plane, paralleling the course of the original major fissure but displaced anteriorly and superiorly. In seven of 20 patients (35%) the superior aspect was coronal, rotated clockwise toward the sagittal plane inferiorly. In one of 20 patients (5%) the neofissure was oriented predominantly in the sagittal plane. The right middle lobe lies anterior and medial to the neofissure; the right lower lobe lies posterior and lateral.     

Permanent inflation of detachable balloons with a low-viscosity, hydrophilic polymerizing system

A polymer system was developed for use in permanent inflation of detachable balloons, to avoid long-term reliance on the integrity of balloon shells or valve mechanisms. This system is based on 2-hydroxy-ethyl methacrylate (HEMA) as the monomer, in combination with a cross-linking agent and a water-soluble curing system. The low-viscosity, hydrophilic mixture can be exchanged through a small-bore catheter into a detachable balloon and polymerizes in 40-60 minutes at body temperature. Partially polymerized HEMA can cause vascular occlusion; hence, careful timing of balloon detachment is required. The evolution of the radiographic appearance of HEMA-filled balloons is predictable. The balloons remain radiopaque on plain radiographs as long as the balloon shell and valve mechanisms are competent. After rupture of the shell or failure of the valve mechanism, the balloons become invisible on plain radiographs but remain hyperattenuating on computed tomography scans.     

Radiologic diagnosis of oat cell cancer in a high-risk screened population

A screening program of 10,040 cigarette-smoking men over 45 years of age was undertaken in an attempt to achieve earlier diagnosis, thereby increasing the cure rate, of oat cell lung cancer. Of the 155 men who were found to have lung cancer, 27 (17%) had confirmed oat cell cancer. Only one case was diagnosed at the first examination. The other 26 cases (called incidence cancer) were diagnosed by subsequent examinations. In 24 of the 26 patients, the tumor was not found until it was advanced (Stage III), and of these patients, only one is alive at 21 months follow-up. Two tumors were diagnosed as oat cell carcinoma at an early stage (Stage I), and both patients are alive with no evidence of disease at seven and 24 months. The screening program used in this study did not succeed in detecting oat cell cancer at an early stage.