Are «off hours» intubations a risk factor for complications during intubation? A prospective, observational study

OBJECTIVE

To compare the complications and the difficulty of orotracheal intubation procedures performed in the Intensive Care Unit during the off-hours period and the on-hours period.

DESIGN

A prospective, observational and non-interventional cohort study covering a period of 27 months was carried out. Working days between 8:00 a. m. and 7:59 p. m. were considered «on-hours», while the remaining shifts were regarded as «off-hours».

SCOPE

An 18-bed surgical in a Intensive Care Unit of a third-level hospital.

PATIENTS

All orotracheal intubation patients admitted to the ICU from January 2015 to March 2017 were included. Patients were stratified into 2groups according to whether intubation was performed on-hours or off-hours.

INTERVENTIONS

Non-interventional study.

VARIABLES OF INTEREST

The reason for intubation, time and day on which intubation was performed, degree of intubation difficulty (number of attempts, Cormack-Lehane laryngoscopic vision, need for accessory material) and complications during intubation.

RESULTS

A total of 252 patients were intubated; of these, 132 were included in the on-hours group and 120 patients in the off-hours group. In the off-hours group we observed a greater percentage of urgent and emergent intubations compared to the on-hours group. However, no differences were found between the 2groups in relation to the other variables studied.

CONCLUSIONS

During the off-hours period, orotracheal intubation was not associated to a greater number of complications or to greater difficulty of the technique in our Unit.

SHP-1 expression in peripheral T cells from patients with Sezary syndrome and in the T cell line HUT-78: implications in JAK3-mediated signaling

SHP-1 is a key tyrosine phosphatase that acts as a negative regulator of signal transduction in lymphocytes, which has been found down-regulated in several T cell lines derived from human T cell malignancies. The standardization of a sensitive ELISA for the quantification of SHP-1 protein in peripheral T and B lymphocytes has enabled us to quantify the SHP-1 content of freshly isolated T cells from patients with Sezary syndrome and in the Sezary T cell line HUT-78. In all cases, a dramatic decrease in the content of this protein, when compared with the content in healthy volunteer controls, was observed. These results were corroborated when the expression of SHP-1 mRNA was analyzed. In order to study whether there was any correlation between SHP-1 protein expression and tyrosine phosphorylated state of JAK3, the state of phosphorylation of JAK3 was studied in the T cell line HUT-78, and found to be highly phosphorylated. These results suggest that SHP-1 might be involved in maintaining the IL-2R/JAK3 signaling pathway under control and point towards a role of SHP-1 in the pathogenesis of the disease.

Mechanistic aspects of the induction of apoptosis by lauryl gallate in the murine B-cell lymphoma line Wehi 231

The effect of lauryl gallate (antioxidant E-312) has been studied on the mouse B-cell lymphoma line Wehi 231. This compound is able to inhibit protein tyrosine kinases (PTKs) in whole cells and in crude extracts with a better efficiency than other well-known PTK inhibitors such as herbimycin or genistein. Initial events triggered upon the incubation of cells with lauryl gallate in phosphate-buffered saline (up to 1 h) include the inhibition of tyrosine phosphorylation, discharge of the mitochondrial transmembrane potential, and induction of mRNA for Bcl-2. Long-term cultures in complete medium supplemented with fetal calf serum (up to 24 h) in the presence of this compound exhibit clear apoptotic features such as increase in phosphatidylserine in the cell surface, decrease in the functionality of mitochondria, cytochrome c release to the cytosol, activation of caspases, hypodiploidy, and oligonucleosomal breakdown of DNA. Comparison between Wehi cells overexpressing Bcl-2 (Wehi-bcl-2) with Wehi-neo cells shows a delay in the manifestations of the apoptotic signs, indicating that Bcl-2 has a partial protective effect on the apoptosis induced by lauryl gallate. The proapoptotic effect of lauryl gallate is not dependent on DNA or protein synthesis, is not blocked by the chelation of calcium, and is not reverted by N-acetylcysteine.

Involvement of cyclic GMP in the mode of action of a new antithrombotic agent PCA-4230; inhibition of the platelet cyclic GMP dependent phosphodiesterase

The effect of PCA-4230, a new dihydropyridine derivative with a potent antithrombotic activity, on cyclic nucleotide phosphodiesterase in platelets was studied. PCA-4230 inhibited (54%) cyclic GMP hydrolytic activity of a platelet cytosolic fraction, whereas it did not affect that of cyclic AMP. Results suggested that PCA-4230 inhibited a cyclic GMP-dependent phosphodiesterase, known as cGB PDE or type V, on a purified enzyme from rabbit platelets by a non-competitive-uncompetitive type inhibition. In addition, PCA-4230 potentiated the increase in both cyclic GMP and cyclic AMP levels evoked by sodium nitroprusside. Furthermore, PCA-4230 and forskolin caused a synergistic effect in cyclic AMP, and also potentiated the phosphorylation of 50 kDa and 22 kDa proteins, reported as substrates of cyclic GMP- and cyclic AMP-dependent protein kinases that are related to the inhibition of platelet functions. Finally, PCA-4230 also potentiated the forskolin- and sodium nitroprusside-inhibited serotonin release evoked by thrombin, probably related to the increased cyclic nucleotide level.

Regulation of PAF-induced platelet responses by cyclic nucleotides

The existence of cross-talk mechanisms between the cyclic nucleotide system and other transduction systems involved in PAF-activated platelets is described in this study. A protein of 125 kDa, identified as pp 125(FAK), is tyrosine phosphorylated by PAF in a time- and concentration-dependent manner. The presence of a cAMP- or a cGMP-elevating agent, used alone or in combination, together with PAF diminished tyrosine phosphorylation. The sensitivity to cAMP shown by PAF-induced ppl25 phosphorylation on tyrosine residues was similar to PAF-induced phosphorylation of a 47-kDa protein (pp47) on serine and threonine. In contrast, the latter was not affected in the presence of a cGMP-elevating agent, although it was able to enhance synergistically the inhibitory effect of forskolin. Data reported herein also show that pp47 phosphorylation and serotonin secretion are not closely correlated. Accordingly, sodium nitroprusside (SNP) did not have any effect on phosphorylation of pp47, but it was able to inhibit serotonin secretion when added alone, and it showed a synergistic inhibitory action with forskolin.

PCA-4248, a PAF receptor antagonist, inhibits PAF-induced phosphoinositide turnover

The effect of a new PAF (platelet activating factor; 1-O-alkyl-2-acetyl-sn-glycero-3-phosphoryl-choline) receptor antagonist, PCA-4248 (2-phenylthio)ethyl-5-metoxycarbonyl-2,4,6-trimethyl-1, 4-dihydropyridine-3-carboxylate), on phosphoinositide turnover evoked by PAF was investigated. PAF treatment resulted in an increased 32P incorporation into phosphoinositides and phosphatidic acid in rabbit platelets. Treatment with PCA-4248 abolished both effects in a dose-dependent manner, 10 microM being the most effective dose. In thrombin stimulated platelets, phosphoinositide turnover was not influenced by PCA-4248. In addition, PAF caused a rapid and significant increase in protein phosphorylation. Thus, PAF treatment resulted in a marked phosphorylation of two proteins of 47 kDa and 20 kDa. Treatment with PCA-4248 resulted in an inhibition of these actions. Serotonin secretion evoked by PAF was also inhibited by PCA-4248. It is concluded that PCA-4248 antagonizes the PAF effects by acting as a competitive antagonist at the PAF receptor level as evidenced from binding studies.

Dissociation between secretion and protein phosphorylation in agonist-stimulated platelets; action of PCA-4230, a new antithrombotic drug

We have studied the effects of PCA-4230, a new dihydropyridine derivative with antithrombotic activity, on the secretion of dense and alpha-granules from platelets and on the protein phosphorylation in platelets after stimulation by agonists. The drug prevented both dense and alpha-granule secretion evoked by thrombin, platelet-activating factor (PAF) and ionophore A23187, the former secretion being more sensitive than the latter one to the PCA-4230 action. These inhibitory effects on secretion processes did not correlate with the differential action of PCA-4230 on protein phosphorylation. Thus, the 40 kDa protein phosphorylation evoked by thrombin was potentiated whereas that elicited by ionophore A23187 was partially inhibited. The 20 kDa protein phosphorylation was practically insensitive to the drug action. These data, together with previous evidence reported by us on PCA-4230, lead us to suggest the existence of a common and critical step for platelet secretion evoked by agonists with different signal transduction pathways.

PAF and thrombin actions in platelets are selectively affected by a new 1,4-dihydropyridine derivative

In the present study we described the effects of a new 1,4-dihydropyridine derivative with antithrombotic activity on phosphoinositide turnover in washed platelets stimulated by either platelet-activating factor or thrombin. In 32P-labeled rabbit platelets, both PAF and thrombin evoked a transient loss of [32P]phosphatidylinositol 4,5-bisphosphate (PIP2) and, thereafter, labeling increased over the control value. Concomitantly, a progressive formation of phosphatidic acid was observed. In [3H]arachidonate labeled platelets, both agonists elicited an increase in diacylglycerol (DAG) levels and arachidonate release. Pretreatment of platelets with the new dihydropyridine derivative (PCA-4230) prevents, in a dose-dependent fashion, the PAF-evoked variations in phosphoinositide turnover and DAG production. However, thrombin-induced variations were rather enhanced by PCA-4230. With respect to arachidonate release and platelet aggregation, the drug was again selective against PAF and thrombin. Although PCA-4230 shows some PAF antagonistic activity, its effects on PAF-evoked responses did not seem only due to an antagonism at receptor level. In view of the present results, the drug is not only able to discern the pathways of platelet activation by which PAF and thrombin exert their action, but it also affects selectively the enhanced phosphoinositide turnover and arachidonate release evoked by thrombin. Thereafter, PCA-4230 is a suitable tool to explore the mechanisms of action of the natural agonists.

PAF-induced activation of polyphosphoinositide-hydrolyzing phospholipase C in cerebral cortex

The action of platelet-activating factor (PAF) on phosphoinositide hydrolysis was studied in rat brain slices. PAF produced a significant increase of 32P incorporation into phosphoinositides and phosphatidic acid (PA), in a dose- and time-dependent manner. Concomitantly, an increase of inositol phosphates and diacylglycerol (DAG) production was observed. Both inositol bisphosphate (IP2) and inositol trisphosphate (IP3) were detected as early as 5 s and they returned immediately to basal levels; concomitantly, formation of inositol monophosphate (IP) was detected. These findings demonstrated that PAF causes a rapid hydrolysis of polyphosphoinositides in cerebral cortex by a phospholipase C-dependent mechanism followed by subsequent resynthesis.