Comparison of Positive End-Expiratory Pressure with Reverse Trendelenburg Position in Morbidly Obese Patients Undergoing Bariatric Surgery: Effects on Hemodynamics and Pulmonary Gas Exchange

Background: Anesthetized morbidly obese patients often exhibit impaired pulmonary gas exchanges, mostly because of a reduction in functional residual capacity. At present, several approaches are suggested to ventilate these patients. Methods: The efficiency of positive end-expiratory pressure (PEEP) and reverse Trendelenburg position (RTP) were compared in order to improve oxygenation in 20 morbidly obese patients undergoing bariatric surgery. Results: Both PEEP and RTP determined a significant decrease in alveolar-arterial oxygen difference and an increase in total respiratory compliance (Ctot). RTP resulted in lower airway pressures than PEEP with similar improvements in Ctot and oxygenation. Concerning hemodynamic parameters, cardiac output (CO) significantly decreased with both PEEP and RTP. Conclusions: RTP and PEEP can be considered adequate ventilatory settings for morbidly obese patients, without any significant difference with regard to gas exchange improvement. However, the decrease in CO may partially counteract the beneficial effects on oxygenation of these ventilatory settings.     

Clinical experience with power-injectable PICCs in intensive care patients

Introduction

In the ICU, peripherally inserted central catheters (PICCs) may be an alternative option to standard central venous catheters, particularly in patients with coagulation disorders or at high risk for infection. Some limits of PICCs (such as low flow rates) may be overcome with the use of power-injectable catheters.

Methods

We retrospectively reviewed all of the power-injectable PICCs inserted in adult and pediatric patients in the ICU during a 12-month period, focusing on the rate of complications at insertion and during maintenance.

Results

We collected 89 power-injectable PICCs (in adults and in children), both multiple and single lumen. All insertions were successful. There were no major complications at insertion and no episodes of catheter-related bloodstream infection. Non-infective complications during management were not clinically significant. There was one episode of symptomatic thrombosis during the stay in the ICU and one episode after transfer of a patient to a non-intensive ward.

Conclusion

Power-injectable PICCs have many advantages in the ICU: they can be used as multipurpose central lines for any type of infusion including high-flow infusion, for hemodynamic monitoring, and for high-pressure injection of contrast media during radiological procedures. Their insertion is successful in 100% of cases and is not associated with significant risks, even in patients with coagulation disorders. Their maintenance is associated with an extremely low rate of infective and non-infective complications.     

Effects of oral estrogen, raloxifene and arzoxifene on gene expression in serotonin neurons of macaques

The serotonin neural system contributes to cognition and affect, both of which exhibit pathologies with gender bias. We previously showed that estrogen (E) treatment of female macaques via Silastic implant alters gene expression for tryptophan hydroxylase (TPH), the serotonin reuptake transporter (SERT) and the 5HT1A autoreceptor. In addition, we have found that serotonin neurons of macaques express ER beta (ER beta). Together these studies suggest that the serotonin neural system could transduce the action of estrogen via ER beta on aspects of mood and cognition. However, estrogen replacement therapy can increase the risk for breast and uterine cancer. Therefore, we questioned whether the selective estrogen receptor modulators, raloxifene and arzoxifene, act in a manner similar to E on gene expression in serotonin neurons of a nonhuman primate model. Female rhesus macaques were ovariectomized and orally dosed with vehicle, estradiol 17beta, raloxifene or arzoxifene once per day by sipper bottles for 30 days. The animals were then euthanized and the midbrains were prepared for in situ hybridization for TPH, SERT and 5HT1A receptor mRNAs followed by densitometric analysis. There was a significant increase in TPH total signal (positive pixelsxOD) with E, raloxifene and arzoxifene, respectively. There was a significant decrease in SERT mRNA optical density with all treatments. 5HT1A autoreceptor mRNA did not change with any treatment. If these changes in gene expression are reflected by similar changes in the functional proteins, then raloxifene or arzoxifene could increase serotonin neurotransmission with little or no negative action in peripheral tissues. In conclusion, the selective estrogen receptor modulators, raloxifene and arzoxifene, act in a manner similar to natural E on TPH and SERT mRNA expression in serotonin neurons. This suggests that raloxifene and arzoxifene are agonists at ER beta in the context of the serotonin neuron. However, the responses to E were more variable and less robust with the oral dosing paradigm compared to a chronic implant paradigm.     

Zoonotic babesiosis: Overview of the disease and novel aspects of pathogen identity

Babesiosis is a zoonosis caused by tick-transmitted intraerythrocytic protozoa of the Phylum Apicomplexa. The disease mostly occurs in the USA, but cases have also been reported in several European countries, in Egypt, India, Japan, Korea, Taiwan, and South Africa. The main pathological event is lysis of erythrocytes resulting in haemolytic anaemia, which in severe cases may lead to organ failure and death, particularly in immunocompromised patients. The 2 groups of parasites involved, Babesia microti-like and Babesia sensu stricto (s.s.) species, differ in their life cycle characteristics and susceptibility to antibabesial drugs. Molecular taxonomy is now making a major contribution to the identification of novel pathogens within both groups. Effective treatment of severe cases was initially hampered by the lack of specific antibabesial drugs for human use, but increased use of supportive measures and of the recently developed antimalarial, atovaquone, particularly in combination with azithromycin, has improved the prospects for management of acute disease especially when caused by Babesia s.s. species. Prevention should be based primarily on increasing the awareness of physicians and the public to the risks, but infection from blood transfusions is particularly difficult to prevent. Expanding deer populations, resulting in wider distribution and greater abundance of ticks, heightened medical awareness, and growing numbers of immunocompromised patients are likely to result in a continuing rise of reported cases.     

An experimental study on irritation and annoyance due to passive smoking

Forty subjects were exposed to cigarette smoke produced by a smoking machine in a climatic chamber. The degree of air pollution due to cigarette smoke corresponded to 2.5 and 1.3 ppm delta CO. The concentrations of particulate matter, NO and NO2, were measured. The effects on subjective irritation, annoyance and eye blinking rate were determined. All measured effects increased with increasing smoke concentration as well as with exposure duration. Based on these effects, a tolerable limit in the range between 1.5 and 2.0 ppm delta CO is proposed.     

Cyclotorsional eye movements during a simulated PRK procedure

PURPOSE: Eye alignment is a serious concern when performing corneal surface ablation. Although several excimer lasers monitor horizontal and vertical movements, little is known about the potential impact of cyclotorsional movements. Dynamic cyclotorsions have been measured on 10 emmetropic subjects during a simulated PRK treatment. METHODS: Cyclotorsional eye movements were measured using a 3D videoculographic system (SMI) in 10 emmetropic subjects in upright and supine position. The subjects were wearing an eyelid speculum and were asked to fixate on a 1 degrees red spot. The fixation target was either in focus or optically degraded by electronic filters. Data were collected at the University Eye Clinic, Torino, Italy, and the different setting measurements were compared using Student's t-test for paired data. RESULTS: Cyclotorsions were significantly higher when subjects were fixating an optically degraded stimulus (upright: P=0.04; supine: P=0.0002). The cyclotorsional movements ranged from -13 to 17 degrees. A significant difference in eye orientation was present when changing from the upright to the supine position (P=0.03). Even when correcting for this positional error, significantly higher cyclotorsional movements were detected in the supine position (in focus: P=0.0043; optically degraded: P=0.0008). The torsional range was from -14.85 to 14.55 degrees. CONCLUSIONS: The high range of cyclotorsional eye movements during a simulated PRK procedure suggests that 3D tracking could improve surface ablation results when treating high astigmatism or when wavefront guided.