Infections of all severity can complicate surgery and anesthesia. When the body is fighting off an infection, the physiological stress experienced by the body can impact how anesthesia takes effect. As a result, anesthesiologists must adjust their approach when infections are present.
An infection can trigger widespread inflammation in the body, which may lead to sepsis—a dangerous condition where the immune system harms healthy tissues. In even more severe cases, patients can experience septic shock, where blood pressure drops so low that vital organs like the brain, heart, and kidneys are damaged.¹
Before surgery, doctors will check for signs of infection through tests and physical exams. If an infection is found, it is treated with antibiotics, fluids, and supportive care.² This step helps reduce the risk of complications during anesthesia. For non-emergent surgeries, it is often preferable to treat the infection to resolution before surgery and anesthesia, even if that means delaying the procedure.
Infections affect how the body responds to anesthesia. Patients with serious infections are often unstable, meaning their blood pressure and heart function are sensitive. Some common anesthesia drugs, like propofol, can lower blood pressure even more, which is dangerous.³ Options like ketamine or etomidate are often used when patients are at risk of hemodynamic instability, as they help keep blood pressure steady.⁴ Ketamine may even also possess anti-inflammatory properties, which is an added benefit during infection.⁵
Infections can also interfere with local anesthetics. Infected tissues become more acidic because of inflammation, which makes it harder for these drugs to work effectively.9 This is because local anesthetics rely on chemical reactions that function less well in acidic environments.9 Inflammation also increases blood flow near the infection site, causing local anesthetics to be absorbed and cleared from the area more quickly, consequently shortening their numbing effect.6 Scientists have also found that inflammatory cells release substances that weaken the effectiveness of local anesthetics by affecting how nerve channels work.9 Finally, infections can change how the liver processes drugs, potentially reducing how long anesthesia stays active in the body.9
Patients recovering from serious infection often need extra care, usually in the intensive care unit (ICU). They may need help with breathing or blood pressure control and may require time to fully recover from the infection.8 Medication doses, especially antibiotics and pain relievers, are often adjusted because infections change how the body absorbs and breaks down drugs.9
Infection makes anesthesia more complex, but with careful planning, the right medications, and close monitoring, patients can still have safe surgeries. Anesthesiologists play a vital role in adjusting care to keep patients stable and comfortable during these high-risk procedures.
References
- Singer M, Deutschman CS, Seymour CW, et al. The third international consensus definitions for sepsis and septic shock (Sepsis-3). JAMA. 2016;315(8):801-810. doi:10.1001/jama.2016.0287
- Evans L, Rhodes A, Alhazzani W, et al. Surviving sepsis campaign: international guidelines for management of sepsis and septic shock 2021. Intensive Care Med. 2021;47(11):1181-1247. doi:10.1007/s00134-021-06506-y
- Carsetti A, Vitali E, Pesaresi L, et al. Anesthetic management of patients with sepsis/septic shock. Front Med (Lausanne). 2023;10:1150124. doi:10.3389/fmed.2023.1150124
- Mohr NM, Pape SG, Runde D, et al. Etomidate use is associated with less hypotension than ketamine for emergency department sepsis intubations: a NEAR cohort study. Acad Emerg Med. 2020;27(12):1140-1149. doi:10.1111/acem.14070
- Kawasaki T, Ogata M, Kawasaki C, Ogata JI, Inoue Y, Shigematsu A. Ketamine suppresses proinflammatory cytokine production in human whole blood in vitro. Anesth Analg. 1999;89(3):665-669. doi:10.1213/00000539-199909000-00024
- Becker DE, Reed KL. Essentials of local anesthetic pharmacology. Anesth Prog. 2012;59(2):90-101. doi:10.2344/0003-3006-59.2.90
- Aitken AE, Richardson TA, Morgan ET. Regulation of drug-metabolizing enzymes and transporters in inflammation. Annu Rev Pharmacol Toxicol. 2006;46:123-149. doi:10.1146/annurev.pharmtox.46.120604.141059
- Renton KW. Alteration of drug biotransformation and elimination during infection and inflammation. Pharmacol Ther. 2005;107(1):1-16. doi:10.1016/j.pharmthera.2005.01.001
- Tsai D, Lipman J, Roberts JA. Pharmacokinetic/pharmacodynamic considerations for the optimization of antimicrobial delivery in the critically ill. Curr Opin Crit Care. 2015;21(5):412-420. doi:10.1097/MCC.0000000000000229