[Crystal meth - a new kid on the block]. / Crystal meth ­ een nieuwkomer.

In this article we describe epidemiological, pharmacological and clinical aspects of abuse of metamphetamines, also known as crystal meth. These aspects are illustrated by two cases of methamphetamine abuse and the complications associated with it. Metamphetamine abuse is often associated with sexual activity, a combination known as 'chemsex'. A chronic addiction to chemsex can have devastating effects on the user's social, psychological, and physical wellbeing. We describe a patient suffering from recurrent relapses in his addiction to chemsex. Acute crystal meth intoxications can result in very serious complications. We describe a patient suffering from severe neurological complications and rhabdomyolysis.

[Pulse oximetry: principles, limitations and practical applications]. / Pulsoximeters: werking, valkuilen en praktische tips.

Pulse oximetry detects hypoxemia non-invasively by measuring light absorption at different wave lengths, depending on the oxygenation of hemoglobin. The plethysmographic signal is caused by volume changes in the arterial blood during systole. In this pulsatile flow, oxygen saturation is calculated using an algorithm. Use of the pulse oximeter has increased massively, especially in the COVID-era, and has a central role in managing patients at the emergency department. However, interpretation of the plethysmogram is frequently incorrect which may lead to incorrect conclusions. Moreover, an irregular plethysmographic signal may well 'give' a saturation percentage. We will discuss how pulse oximeters work and discuss some pitfalls. We hope that understanding the mechanism behind pulse oximetry, as well as an awareness of pitfalls, leads to improved management of patients with consequently less unnecessary care, as demonstrated in our case.

[Volume replacement therapy; what is the solution?]. / Volumeresuscitatie, wat is de oplossing?

2 types of infusion solutions are used for volume replacement: crystalline fluids (such as NaCl 0.9% and lactated Ringer's solution) and colloidal fluids made of hydroxyethyl cellulose, albumin or gelatine. The choice of fluids used appears to be determined by the personal preference of the physician or the department. Infusion of colloidal solutions results in rapid recovery of the circulating volume but can cause anaphylaxis, renal insufficiency and an increased bleeding tendency. The use of hydroxyethyl cellulose (HEC) is associated with higher mortality and renal impairment, and is therefore not very justifiable. Albumin-based infusions appear to be predominantly indicated for septic patients with hypoalbuminaemia. Gelatin-based infusion fluids have not yet been extensively studied. The balanced lactated Ringer's solution, the composition of which is closer to plasma than that of NaCl 0.9%, is being used with ever-increasing frequency. Lactated Ringer's infusion solution does not cause hyperchloremic acidosis and probably less often leads to renal insufficiency than when NaCl 0.9% is infused.