lossofresistance

Loss of resistance, sometimes written as Lossofresistance, is a term used in medical and scientific contexts to describe a decline in the ability to resist or cope with a challenge, most commonly infections or the identification of spaces during regional anesthesia.

In clinical medicine, loss of resistance refers to a reduced capacity of the immune system to defend against pathogens. This can result from primary immunodeficiency, acquired conditions such as malnutrition, aging, chronic diseases, or iatrogenic factors like chemotherapy and immunosuppressive therapy. When resistance is diminished, individuals are more susceptible to infections, including opportunistic pathogens. Management focuses on treating the underlying cause, preventing infections through vaccination and hygiene, and, when possible, restoring immune function.

In anesthesiology, loss of resistance is a described tactile or perceptual change used to locate the epidural space during neuraxial anesthesia. During the procedure, a needle is advanced with a syringe attached containing saline or air. When the needle enters the epidural space, the practitioner feels a distinct change in resistance to injection, signaling correct placement. Techniques vary between using saline or air, with contemporary practice often favoring saline to minimize certain risks. Potential complications include dural puncture, post-dural puncture headache, vasovagal reactions, or accidental intravascular injection, underscoring the need for skilled technique and careful monitoring.

See also immunodeficiency, neuraxial anesthesia, epidural space, dural puncture.