The chemistry and toxicology of vaping

Vaping is the process of inhaling and exhaling an aerosol produced by an e-cigarette, vape pen, or personal aerosolizer. When the device contains nicotine, the Food and Drug Administration (FDA) lists the product as an electronic nicotine delivery system or ENDS device. Similar electronic devices can be used to vape cannabis extracts. Over the past decade, the vaping market has increased exponentially, raising health concerns over the number of people exposed and a nationwide outbreak of cases of severe, sometimes fatal, lung dysfunction that arose suddenly in otherwise healthy individuals. In this review, we discuss the various vaping technologies, which are remarkably diverse, and summarize the use prevalence in the U.S. over time by youths and adults. We examine the complex chemistry of vape carrier solvents, flavoring chemicals, and transformation products. We review the health effects from epidemiological and laboratory studies and, finally, discuss the proposed mechanisms underlying some of these health effects. We conclude that since much of the research in this area is recent and vaping technologies are dynamic, our understanding of the health effects is insufficient. With the rapid growth of ENDS use, consumers and regulatory bodies need a better understanding of constituent-dependent toxicity to guide product use and regulatory decisions.

Twenty-four-hour intragastric pH patterns in ICU patients on ranitidine

Thirty critically ill patients with mixed diagnoses underwent continuous intragastric pH monitoring for 72 hr while confined to a shock/trauma intensive care unit. The first 24 hr were monitored under no specific acid-suppressing therapy (placebo control). During the second and third consecutive 24-hr periods, patients received continuous infusion of intravenous ranitidine in the dose of 6.25 mg/hr and 12.5 mg/hr, respectively. Results of the placebo-control 24-hr study revealed that one third (N = 10) of the patients were gastric acid hyposecretors (24-hr median intragastric pH values above pH 4.0). In the normosecreting group (N = 20), both ranitidine schedules significantly elevated 24-hr median pH values, when compared to placebo (placebo 24-hr median intragastric pH 1.75; ranitidine 6.25 mg/hr 24-hr median intragastric pH 4.625, P < 0.0001; ranitidine 12.5 mg/hr 24-hr median intragastric pH 6.29, P = 0.0099). Five patients (18%) failed to adequately respond to the ranitidine 12.5 mg/hr dose (24-hr median intragastric pH < 4.0). These findings suggest that a significant percentage of intensive care unit patients are not in need of acid-suppressing therapy as prophylaxis against stress-induced ulceration. Conversely, other patients may require more intensive acid-suppressing regimens because of failure to respond to high dose H2-antagonist therapy.

[Bowel preparation before colonoscopy: personal experience and brief literature review]

INTRODUCTION

Colonoscopy is the most commonly used technique for inspection of the colonic mucosa. The safety and effectiveness of colonoscopy in identifying important colonic pathology is directly impacted by the operator experience and by the quality of the bowel preparation performed in anticipation of the procedure.

PATIENTS AND METHODS

From December 2000 to June 2006, we performed 8328 total colonoscopy (M:F ratio =1:1.8, mean age 54.7 years, range 16-93). All the patients were submitted to routinary bowel preparation with polyethylenglycol (PEG) the evening before the exam, with fibres diet restriction 5 days before the exam.

RESULTS

On 8328 colonoscopy, 1243 were not actable for worst/absent intestinal toilette. 423 colonoscopy were completed after visceral washing with saline solution during the exam. On 1243 colonoscopy repeated, 852 were in subjects affected by diabetes (p < 0.05); in these patients we prescribed 5 litres solution of PEG one day before the endoscopy, diet without fibers 7 days before the exam and the use of 250 ml solution of PEG (bid): with these method, all the patients were submitted successfully to colonoscopy and retrograde ileoscopy.

DISCUSSION

Physicians favor preparations associated with the best patient compliance to achieve the best results. Patients favour preparations that are low in volume, palatable, have easy to complete regimens, and are reimbursed by health insurance or are inexpensive. Both patients and physicians favor preparations that are safe to administer in light of existing comorbid conditions and those that will not interact with previously prescribed medications.

CONCLUSIONS

Today doesn't exist the "gold standard" for bowel preparation before colonoscopy. Basing on our experience, the 4 litres PEG solution mentioned above is well tolerated and effective. In patients with severe comorbidity (diabetes, renal failure, high blood pressure) only little modifications are required to optimize the colon cleansing.