Читать книгу Fundamentals of Pharmacology for Paramedics - Группа авторов - Страница 35

Administration of medications in the out‐of‐hospital setting can be challenging due to poor lighting, uncontrolled environment or a chaotic scene. Practising all steps of safe medication administration is key to reducing the risk of error (Chapter 4 discusses medicines management and the role of the paramedic). Ensuring the same routine is exercised every single time you administer any medications will embed safe practice so you do not overlook a crucial step during a high‐acuity incident.

Hand hygiene is important to prevent introduction of harmful pathogens in the out‐of‐hospital environment. Access to running water may not be practical in the out‐of‐hospital setting, so utilisation of alcohol‐based hand rub is the gold standard in this setting. Healthcare‐associated infections generate significant comorbidity and burden for the patient, the community and the healthcare system. Healthcare‐associated infections are avoidable and simple hygienic practice and aseptic technique are crucial in breaking the chain of transmission from community, to patient and into care settings such as hospitals.

Intravenous cannulation is a key source for bloodstream infections and risk mitigation efforts, such as use of alcohol‐based hand rub and not touching the area between cleaning the skin and immediately prior to cannulation, should be exercised.

Other routes of administration which are common in the out‐of‐hospital setting include

intravenous, intramuscular, topical, intranasal, endotracheal and intraosseous. See Chapter 6 for further discussion.

Once absorbed into the bloodstream, a drug needs to be able to penetrate to its sites of action relatively quickly. If the drug was an antimicrobial being used to treat an infection of the blood, then getting enough drug into the bloodstream for long enough would be all that was required. However, if the drug were required to penetrate the central nervous system, for example, or get into joint spaces or some other protected body compartment, then it would also have to be able to move out of the bloodstream and travel through the cellular walls that form those body compartments. This presents another challenge to a molecule; in order to get through cell membranes, a drug molecule either needs to be soluble in lipids (lipophilic) or, if it is more water soluble (hydrophilic), then it would have to be a very small molecule. Drugs that are highly lipid soluble are generally able to move readily through cellular compartments without difficulty, and will therefore leave the bloodstream and enter the tissues, often concentrating there. Drugs that readily cross the blood–brain barrier, such as those used in general anaesthesia, are highly lipid soluble, allowing them to pass very rapidly into the protected environment of the brain, which explains their ability to produce general anaesthesia in a matter of seconds after being introduced into a vein.

The dose, route and timing of administration will all play key roles in the effectiveness of the drug. This is discussed in greater detail in Chapter 5.