Desflurane is an inhalational anesthetic drug used for induction and maintenance of anesthesia in adults and maintenance of anesthesia in children.¹ It was first created in the 1970s, and when it was first introduced to the market, it was difficult to synthesize and expensive.¹ However, it has the most rapid onset of all inhalational anesthetic drugs, which allowed it to become popular despite cost and other difficulties.¹ Additionally, the delivery method of the drug can improve its cost-effectiveness, reducing the prohibitive cost.² Today, Suprane is the well-known brand name for desflurane.³ Given the widespread use of desflurane and its advantages, anesthesia providers should understand its biochemical mechanisms, surgical applications and side effects.

The chemical name for desflurane is 1,2,2,2-tetrafluoroethyl difluoromethyl ether.¹ Like many other inhalational anesthetics, desflurane is a halogenated ether.⁴ However, desflurane is only halogenated by fluorine, and it is very resistant to defluorination.¹ Because of this stability and the fact that it undergoes almost no metabolism, it is associated with less hepatotoxicity (i.e., liver damage) than inhalational anesthetics like halothane.^5,6 To a small degree, though, desflurane is metabolized by the enzyme CYP2E1 to a trifluoroacetic acid, which leads to the body’s production of antibodies.⁵ Although the mechanism of action of inhalational anesthetics remains unclear,¹ volatile agents such as desflurane may activate gamma aminobutyric acid (GABA) channels and hyperpolarize cell membranes.⁷ In addition, it may inhibit certain calcium channels, thereby preventing the release of neurotransmitters and inhibiting glutamate channels.⁷ Other proposals state that these anesthetics work by affecting the membrane bilayer of cells.¹ Its actions occur throughout the central and peripheral nervous systems, and it has an overall inhibitory effect.¹

Desflurane has a variety of surgical and anesthetic applications.¹ Because it has a pungent odor, it is less often used for anesthetic induction than for anesthetic maintenance.¹ That is, it is usually applied after initial administration of another intravenous or inhalational anesthetic drug.¹ Desflurane has a low blood-gas solubility similar to that of nitrous oxide, which makes it a potent inhalational anesthetic with a quick induction and fast recovery time.^6,8 During surgery, desflurane has numerous effects on various body systems. The cardiovascular effects of desflurane entail vasodilation, which results in dose-dependent reductions in vascular resistance and arterial blood pressure.⁹ Desflurane is better than other inhaled anesthetics in maintaining blood pressure control.⁹ The neuromuscular effects of desflurane contribute to its use as an anesthetic, as it causes dose-dependent depression of brain activity, muscle relaxation and potentiation of neuromuscular blocking agents.⁹ Desflurane can be used for Cesarean section¹⁰ or for pain control during vaginal delivery.¹¹ Though desflurane is not approved for induction in children, its rapid recovery profile is helpful for geriatric, obese and other adult populations.⁹

Like any general anesthetic, desflurane is associated with several side effects. It can cause moderate to severe upper airway events in children,¹ and should be avoided in patients with liver disease or history of malignant hyperthermia.¹² As desflurane is a strong-smelling airway irritant, it can cause coughing, breath holding, laryngospasm (constriction of the laryngeal muscles) and sialorrhea (hypersalivation).⁶ Rapid increases in the concentration of desflurane can cause elevation in heart rate and blood pressure.¹ Common postoperative side effects include bluish lips or skin, body aches, congestion, fever, trouble breathing or swallowing and voice changes.¹² Patients should seek medical attention if they experience any distressing side effects.

Desflurane has advantages over other anesthetics, such as rapid induction and recovery times and lack of liver damage. It can be used to lower blood pressure, brain activity and muscle movement during general anesthesia. Given its pungent odor, desflurane’s most common side effects include coughing, breath holding and other respiratory issues. Though desflurane is not risky for most patients, patients should give their anesthesia providers a full medical history to avoid complications.

1. Khan J, Liu M. Desflurane. StatPearls. Treasure Island, Florida: StatPearls Publishing; October 2, 2019.
2. De Medts R, Hendrickx JFA, De Wolf AM, Carette R. Sevoflurane or desflurane: Which one is more expensive? Canadian Journal of Anesthesia/Journal canadien d’anesthésie. 2016;63(3):358–359.
3. RxList. Drug Description. Suprane 2020; https://www.rxlist.com/suprane-drug.htm#description.
4. Hudson AE, Herold KF, Hemmings HC. Chapter 10—Pharmacology of Inhaled Anesthetics. In: Hemmings HC, Egan TD, eds. Pharmacology and Physiology for Anesthesia. Philadelphia: W.B. Saunders; 2013:159–179.
5. Safari S, Motavaf M, Seyed Siamdoust SA, Alavian SM. Hepatotoxicity of halogenated inhalational anesthetics. Iranian Red Crescent Medical Journal. 2014;16(9):e20153.
6. Desflurane. ScienceDirect. Web: Elsevier B.V.; 2020.
7. Desflurane. DrugBank February 3, 2020; https://www.drugbank.ca/drugs/DB01189.
8. Inhalational anesthetics (Volatile anesthetics). Clinical Science December 5, 2019; https://www.amboss.com/us/knowledge/Inhalational_anesthetics.
9. Kapoor MC, Vakamudi M. Desflurane–revisited. Journal of Anaesthesiology, Clinical Pharmacology. 2012;28(1):92–100.
10. Abboud TK, Zhu J, Richardson M, Peres da Silva E, Donovan M. Desflurane: A new volatile anesthetic for cesarean section. Maternal and neonatal effects. Acta Anaesthesiologica Scandinavica. 1995;39(6):723–726.
11. Abboud TK, Swart F, Zhu J, Donovan MM, Peres Da Silva E, Yakal K. Desflurane analgesia for vaginal delivery. Acta Anaesthesiologica Scandinavica. 1995;39(2):259–261.
12. Mayo Clinic. Desflurane (Inhalation Route). Drugs and Supplements January 1, 2020; https://www.mayoclinic.org/drugs-supplements/desflurane-inhalation-route/side-effects/drg-20063377?p=1.

Pediatric surgery is defined by the American Board of Surgery as “the diagnostic, operative and postoperative surgical care for children with congenital and acquired anomalies and diseases, be they developmental, inflammatory, neoplastic or traumatic.”¹ The ages of pediatric patients range from in utero to young adulthood, and some patients need to be following through their transition to adult surgeons and clinicians.¹ Surgery, chronic illness and hospitalization can be traumatic to children and their parents.² Children are particularly vulnerable and may have difficulty understanding and managing such experiences.² This, combined with the physical toll that surgery places on a child, can lead to long-term somatic and psychological issues.³ Recent research has focused on the effects of general anesthesia on a child’s developing brain, specifically in regard to attention-deficit/hyperactivity disorder (ADHD).⁴ Anesthesia providers should be familiar with the signs of ADHD, the effects of general anesthesia on children and recent research on pediatric general anesthesia and ADHD.

Evidently, many childhood factors can contribute to children developing psychiatric disorders such as ADHD. For example, a study by Ari et al. found that 10.39 percent of children who were hospitalized in a pediatric surgical ward showed signs of post-traumatic stress disorder (PTSD) three to five months after hospitalization.⁵ Meentken et al.’s review found PTSD prevalence ranges between 12 and 31 percent in children and adolescents who underwent several surgeries for congenital heart defects.⁶ Some research suggests that mental and developmental disorders may be related to exposure to general anesthesia at a young age. According to Schneuer et al.’s study of 211,978 children in Australia, children exposed to general anesthesia before four years of age had poorer development at school entry and school performance.⁷ Meanwhile, Warner et al.’s study did not find deficits in general intelligence linked to anesthesia exposure before three years of age.⁸ However, they found that multiple exposures to general anesthesia were associated with neuropsychological changes causing behavioral and learning difficulties.⁸ Thus, research tentatively suggests that early exposures to surgery and general anesthesia may have a causative relationship with psychological and neurological difficulties.

ADHD is a psychiatric disorder marked by difficulty paying attention, hyperactivity and acting without thinking that get in the way of functioning or development.⁹ A person with ADHD may make frequent errors in schoolwork, have problems sustaining attention or listening, fail to follow through on instructions or finish tasks, find organization difficult, lose things and become easily distracted.⁹ Although the signs and symptoms of ADHD begin in childhood, the disorder can continue throughout adolescence and adulthood.⁹ Risk factors for ADHD include having a family member with ADHD or another mental disorder; exposure to environmental toxins, such as lead; maternal drug use, alcohol use or smoking during pregnancy; or premature birth.¹⁰ ADHD can be a difficult condition for children as well as their parents.

Several studies have focused on general anesthesia’s relationship with ADHD, as it is a common learning and behavioral disorder. A study by Ing et al. found that children who undergo minor surgery requiring anesthesia under age five have a small increased risk of mental disorder, developmental delay and ADHD diagnoses.¹¹ Similarly, Tsai et al. found that children with multiple or greater than three hours exposure to general anesthesia before three years of age had an increased likelihood of a later ADHD diagnosis.¹² Sprung et al.’s study also showed that children repeatedly exposed to general anesthesia before two years of age were at risk for later development of ADHD.¹³ In their review, Xu et al. summarize molecular and neural mechanisms and animal studies that show how general anesthesia may be causally linked to ADHD.¹⁴ However, many researchers remain skeptical of these results, and almost all stress that a causal link cannot be made conclusively. Though Hu et al. found that multiple pediatric exposures to general anesthesia were associated with increased frequency of learning disabilities and ADHD, the authors emphasize that these data do not show whether anesthesia is the causative agent.¹⁵ Efron et al. warn that suggesting anesthesia causes ADHD is a large, unfounded step that could generate unnecessary public panic.⁴ The authors state that evidence is weak for many environmental factors that supposedly cause ADHD, including general anesthesia.⁴ There is still considerable debate on general anesthesia’s effects on the growing brain, and higher-powered studies are needed to make proper conclusion.¹⁶

Surgery can be psychologically and physically stressful for children and their families. Anesthesia providers should have knowledge of the effects of general anesthesia in children, the signs of ADHD in particular and the possible relationship between general anesthesia exposure and ADHD. Given that the link between pediatric general anesthesia and later development of ADHD is still unclear, future studies should reduce confounding factors and take a longitudinal approach.

1. The American Board of Surgery. Specialty of Pediatric Surgery Defined. Pediatric Surgery May 2019; http://www.absurgery.org/default.jsp?aboutpediatricsurgerydefined.
2. Association of Child Life Professionals. The Case for Child Life. The Child Life Profession 2018; https://www.childlife.org/the-child-life-profession/the-case-for-child-life.
3. Winthrop AL. Health-related quality of life after pediatric trauma. Current Opinion in Pediatrics. 2010;22(3):346–351.
4. Efron D, Vutskits L, Davidson AJ. Can We Really Suggest that Anesthesia Might Cause Attention-deficit/Hyperactivity Disorder? Anesthesiology: The Journal of the American Society of Anesthesiologists. 2017;127(2):209–211.
5. Ari AB, Peri T, Margalit D, Galili-Weisstub E, Udassin R, Benarroch F. Surgical procedures and pediatric medical traumatic stress (PMTS) syndrome: Assessment and future directions. Journal of Pediatric Surgery. 2018;53(8):1526–1531.
6. Meentken MG, van Beynum IM, Legerstee JS, Helbing WA, Utens EMWJ. Medically Related Post-traumatic Stress in Children and Adolescents with Congenital Heart Defects. Frontiers in Pediatrics. 2017;5:20.
7. Schneuer FJ, Bentley JP, Davidson AJ, et al. The impact of general anesthesia on child development and school performance: A population-based study. Paediatric Anaesthesia. 2018;28(6):528–536.
8. Warner DO, Zaccariello MJ, Katusic SK, et al. Neuropsychological and Behavioral Outcomes after Exposure of Young Children to Procedures Requiring General Anesthesia: The Mayo Anesthesia Safety in Kids (MASK) Study. Anesthesiology. 2018;129(1):89–105.
9. National Institute of Mental Health. Attention-Deficit/Hyperactivity Disorder (ADHD): The Basics. Brochures and Fact Sheets 2016; https://www.nimh.nih.gov/health/publications/attention-deficit-hyperactivity-disorder-adhd-the-basics/index.shtml.
10. Mayo Clinic. Attention-deficit/hyperactivity disorder (ADHD) in children. Diseases & Conditions June 25, 2019; https://www.mayoclinic.org/diseases-conditions/adhd/symptoms-causes/syc-20350889.
11. Ing C, Sun M, Olfson M, et al. Age at Exposure to Surgery and Anesthesia in Children and Association With Mental Disorder Diagnosis. Anesthesia and Analgesia. 2017;125(6):1988–1998.
12. Tsai C-J, Lee CT-C, Liang SH-Y, Tsai P-J, Chen VC-H, Gossop M. Risk of ADHD After Multiple Exposures to General Anesthesia: A Nationwide Retrospective Cohort Study. Journal of Attention Disorders. 2015;22(3):229–239.
13. Sprung J, Flick RP, Katusic SK, et al. Attention-deficit/hyperactivity disorder after early exposure to procedures requiring general anesthesia. Mayo Clinic Proceedings. 2012;87(2):120–129.
14. Xu L, Hu Y, Huang L, et al. The association between attention deficit hyperactivity disorder and general anaesthesia: A narrative review. Anaesthesia. 2019;74(1):57–63.
15. Hu D, Flick RP, Zaccariello MJ, et al. Association between Exposure of Young Children to Procedures Requiring General Anesthesia and Learning and Behavioral Outcomes in a Population-based Birth Cohort. Anesthesiology. 2017;127(2):227–240.
16. Disma N, O’Leary JD, Loepke AW, et al. Anesthesia and the developing brain: A way forward for laboratory and clinical research. Pediatric Anesthesia. 2018;28(9):758–763.

Antibiotics are powerful medications that fight bacterial infections by either killing bacteria or keeping them from reproducing.¹ Some well-known bacterial infections that can be treated with antibiotics include pneumonia, tuberculosis, sinusitis, urinary tract infections and sexually transmitted diseases.² They do not fight infections from viruses, such as colds or coughs, the flu, bronchitis and sore throats (except those caused by Group A streptococcus).¹ Despite historical views of antibiotics like penicillin as “wonder drugs,”³ their misuse and overuse can lead to antibiotic resistance, in which certain strains of bacteria no longer respond to antibiotics.⁴ Anesthesia providers frequently administer antibiotics to prevent postoperative infections.⁵ Thus, anesthesiology professionals must be knowledgeable about the importance of antibiotics in anesthesia care, the need for adequate training on antibiotics and the potential harms of antibiotic use.

Anesthesia providers are routinely involved in the provision, but not selection, of preoperative antibiotics.⁶ This is likely because the prevention of infections at surgical sites is highly dependent on the timing of antibiotic administration, and anesthesia providers are well-positioned to administer antibiotics at an appropriate time.⁶ Depending on the risk of infection for the procedure,⁷ the anesthesiology professional will administer prophylactic antibiotics during the immediate preoperative and intraoperative periods.⁵ By administering the antibiotic, the anesthesia provider can also take away burden from floor nurses, prevent delays to the operating room and reduce errors of omission by clarifying the antibiotic type with the surgeon.⁸ Antibiotic administration can be crucial for procedures with high infection rates, as surgical site infections increase the duration of hospital stay and total hospital expenses.⁷

The anesthesiology professional’s role includes determining the appropriate dosage of the antibiotic, which is a complicated endeavor.⁷ Decisions about antibiotic type and dosing are tailored to the surgical procedure and the individual patient based on age, size, renal function, allergies and more.^7,9 Several articles by different anesthesia providers address their discomfort with their level of training in antibiotic therapy.^5,7,9,10 A survey study by Warters et al. found that in general, anesthesiologists felt they had inadequate education in antibiotic therapy.⁶ According to Marymont et al., current anesthesiology residency programs do not impart the knowledge required to make the anesthesiologist responsible for appropriate dosing.⁹ This education gap can cause anesthesia providers to perform tasks and make complex decisions outside of their comfort zones.⁷

Antibiotics can also prevent a variety of harms that make antibiotic administration more complex or risky. For example, patients can have sensitivities or allergies to antibiotics.⁷ Thus, the anesthesia provider must be sure the patient has performed an antibiotic sensitivity test before the procedure.⁷ If testing has not occurred, the anesthesia provider can perform a scratch or puncture test before more definitive intradermal testing.⁷ Additionally, antibiotics can interact with anesthetic drugs in a variety of ways, with the most severe interactions resulting in organ toxicity.⁵ According to a paper by Kang, most antibiotics can cause neuromuscular blockade alone and can also potentiate blockade when combined with neuromuscular blockers.¹¹ The anesthesia provider must be aware of side effects associated with antibiotic therapy before administering antibiotic or anesthetic drugs.⁵

Another debate about anesthesia providers’ use of antibiotics stems from a potentially global problem: antibiotic resistance. Antibiotic resistance occurs when a bacterium has changed slightly to protect itself or neutralize a medication.⁴ Then, this bacterium is able to multiply and pass on its resistant properties, resulting in a bacterial population that is partially or completely resistant to antibiotic medication.⁴ According to the Centers for Disease Control and Prevention (CDC), up to one-third to one-half of antibiotic use in humans is unnecessary or inappropriate.⁴ This applies to anesthesiology as well, as various studies have shown that antibiotic prophylaxis is not indicated for procedures with low infection rate.⁷ In these cases, the risk of adverse medication reaction or antibiotic resistance is higher than the expected benefit of antimicrobial treatment.⁷ As the CDC moves forward with initiatives to prevent antibiotic resistance, anesthesia providers may have to alter their use of antibiotics.¹²

Antibiotics are commonly used to fight postoperative infections. Because of anesthesia providers’ role in medication administration, they are well-positioned to give antibiotic therapy. However, many anesthesiologists do not feel properly trained in the provision of antibiotics. Antibiotic therapy can be complicated and is associated with several interactions and side effects, including bacterial resistance. Leaders in the field should provide anesthesiology professionals with more training in antibiotic therapy⁷ and standardized protocols for antibiotic provision.^6,13

1. Antibiotics. MedlinePlus. Bethesda, MD: National Institutes of Health; April 18, 2019.
2. Felman A. Everything you need to know about infections. Medical News Today August 22, 2017.
3. Microbiology Society. The history of antibiotics. Antibiotics and antibiotic resistance 2020; https://microbiologysociety.org/members-outreach-resources/outreach-resources/antibiotics-unearthed/antibiotics-and-antibiotic-resistance/the-history-of-antibiotics.html.
4. Mayo Clinic. Antibiotics: Are you misusing them? Consumer Health: In-Depth January 18, 2018; https://www.mayoclinic.org/healthy-lifestyle/consumer-health/in-depth/antibiotics/art-20045720.
5. Cheng EY, Nimphius N, Hennen CR. Antibiotic therapy and the anesthesiologist. Journal of Clinical Anesthesia. 1995;7(5):425–439.
6. Warters RD, Szmuk P, Pivalizza EG, Gebhard RE, Katz J, Ezri T. The Role of Anesthesiologists in the Selection and Administration of Perioperative Antibiotics: A Survey of the American Association of Clinical Directors. Anesthesia & Analgesia. 2006;102(4):1177–1182.
7. Tewari A, Garg S, Kaul Tej K. Anesthesiologists and Perioperative Antibiotic Prophylaxis. Anesthesiology: The Journal of the American Society of Anesthesiologists. 2004;101(1):259.
8. Roth Jonathan V, M.D. More Reasons Why Anesthesiologists Should Administer Preoperative Antibiotics. Anesthesiology: The Journal of the American Society of Anesthesiologists. 2004;101(1):258–259.
9. Marymont J, Vender JS, Novak T, Katz J, Silk V. Antibiotics and the Anesthesiologist: Is There a “Consensus?”. Anesthesia & Analgesia. 2017;125(3):1080.
10. Warters RD, Szmuk P, Pivalizza Evan G, Gebhard R, Ezri T. Preoperative Antibiotic Prophylaxis: The Role of the Anesthesiologist. Anesthesiology: The Journal of the American Society of Anesthesiologists. 2003;99(2):515–516.
11. Kang J-M. Antibiotics and muscle relaxation. Korean Journal of Anesthesiology. 2013;64(2):103–104.
12. National Center for Emerging and Zoonotic Infectious Diseases (NCEZID) Division of Healthcare Quality Promotion (DHQP). What CDC is Doing: Antibiotic Resistance (AR) Solutions Initiative. Antibiotic / Antimicrobial Resistance (AR / AMR) November 4, 2019; https://www.cdc.gov/drugresistance/solutions-initiative/.
13. Mutlak H, Maurer O, Zacharowski K, Schön J, Jacob M, May M. An anesthesia perspective on surgical antibiotic prophylaxis: Results of a comprehensive infectiology survey study in German hospitals. American Journal of Infection Control. 2019;47(2):222–223.

Smoking is the leading cause of preventable death worldwide.1 Cigarette smoking is responsible for more than 480,000 deaths per year in the United States, including more than 41,000 deaths from secondhand smoke exposure.1 People who smoke cigarettes are also at higher risk for developing heart disease, stroke and lung cancer than nonsmokers, and smoking causes worse overall health, increased absenteeism from work and higher need for health care.2 Because an estimated 34.2 million adults in the United States smoke cigarettes,3 health care providers should be prepared to care for patients who smoke. Anesthesia providers in particular should consider the smoking status of their patients, as cigarette use increases the risk of perioperative morbidity and mortality.4 Anesthesiology professionals can take steps before, during and after a procedure to prevent complications in patients who smoke cigarettes.

Preoperative preparation for surgery is extremely important in patients who smoke, and it begins at least eight weeks before a procedure.5 A variety of substances in cigarette smoke incur harm to the cardiovascular, respiratory and gastrointestinal systems.4 Thus, anesthesia providers should always ask their patients about smoking and advise smokers to quit at every visit.6 It is also vital to screen patients who may be involuntarily ingesting tobacco through second-hand or third-hand smoke, as these patients may be subject to similar health issues.5,7,8 A study by Zaballos et al. found that though 75 percent of anesthesiologist participants stated they frequently or almost always advised patients about the health risks of smoking, patients said only 31 percent advised about the health risks of smoking and 23 percent advised patients to quit.9 Evidently, there may be gaps in smoking cessation education before surgery. As quitting smoking is crucial for patients to safely undergo anesthesia, the anesthesia provider is well-positioned to improve short-term surgical outcomes as well as long-term health outcomes.10 The anesthesiology professional should be in contact with the patient for several months before surgery and implement a brief smoking cessation intervention.6 If possible, this preoperative cessation should be accompanied by intensive counseling, pharmacotherapy and follow-ups to increase the likelihood that the patient does not return to smoking.6 For patients who have recently quit smoking, anxiolytic premedication with deep anesthesia should reduce any withdrawal-related problems.5 Overall, preoperative smoking cessation and premedication with anxiolytics are key to providing quality care to patients who smoke.

During a procedure, the anesthesia provider must consider the physiological effects of regular cigarette smoking. According to a paper by Rodrigo, there is evidence that some substances in cigarette smoke interfere with drug metabolism, particularly for muscle relaxants.5 Some studies have also investigated the potentially altered effects of neuromuscular blocks in patients who smoke, with mixed results.4 However, there is no doubt that smokers are at higher risk for cardiovascular disease, as cigarettes have adverse effects on lipid profiles, endothelial injury and atherosclerotic plaque development.4 Woehlck et al. found that patients who smoked up until the time of surgery showed heart rate abnormalities during the procedure.11 Smokers also show respiratory issues, with an increased incidence of cough, breath holding and laryngospasm during surgery.12 According to a study by Schwilk et al., smokers had a much higher risk than nonsmokers of intraoperative events such as re-intubation, laryngospasm, bronchospasm, aspiration, hypoventilation/hypoxemia and others.13 Because smokers have hypersensitive airways, anesthesia providers may need to alter their ventilation practices.4 Indeed, Schwilk et al. also showed that problems with intubation and airway management were common in smokers.13 These respiratory issues extend to children who are exposed to environmental smoke, according to a study by Chiswell and Akram.14 Furthermore, smoking causes an increased incidence of gastrointestinal reflux, which may affect a patient’s risk of aspiration during surgery.4 Clearly, cigarette smoking can put patients at higher risk for intraoperative anesthesia-related complications.

After a procedure, the anesthesia provider should be aware of potential complications that may arise in a patient who smokes. Smokers will need more oxygen therapy and more analgesic drugs,5 such as opioids.4 Though they have a reduced rate of postoperative nausea and vomiting compared to nonsmokers,4 patients who smoke are at higher risk for postoperative pneumonia, cardiac arrest, myocardial infarction and stroke.15 Additionally, several studies show that cigarette smokers have delayed wound and bone healing and higher risk of infection,10,15 which can be somewhat alleviated by preoperative smoking cessation.6 The anesthesia provider’s role includes preventing these postoperative complications and monitoring them if they arise.

Cigarette smoking is a leading cause of morbidity and mortality across the world. It can cause numerous surgery- and anesthesia-related complications in cardiovascular, respiratory and other body systems. The anesthesia provider is well-positioned to help a patient quit smoking before surgery. Anesthesiology professionals will also need to monitor a patient who smokes during and after surgery to prevent health problems or death. Future research should examine the anesthesia provider’s role in helping patients quit smoking permanently.

1. Office on Smoking and Health. Fast Facts. Smoking & Tobacco Use November 15, 2019; https://www.cdc.gov/tobacco/data_statistics/fact_sheets/fast_facts/index.htm.
2. Office on Smoking and Health. Health Effects of Cigarette Smoking. Smoking & Tobacco Use January 17, 2018; https://www.cdc.gov/tobacco/data_statistics/fact_sheets/health_effects/effects_cig_smoking/index.htm.
3. Office on Smoking and Health. Current Cigarette Smoking Among Adults in the United States. Smoking & Tobacco Use November 18, 2019; https://www.cdc.gov/tobacco/data_statistics/fact_sheets/adult_data/cig_smoking/index.htm.
4. Carrick MA, Robson JM, Thomas C. Smoking and anaesthesia. BJA Education. 2019;19(1):1–6.
5. Rodrigo C. The effects of cigarette smoking on anesthesia. Anesthesia Progress. 2000;47(4):143–150.
6. Yousefzadeh A, Chung F, Wong DT, Warner DO, Wong J. Smoking Cessation: The Role of the Anesthesiologist. Anesthesia & Analgesia. 2016;122(5):1311–1320.
7. Tønnesen H, M.D., D.M.Sc. Surgery and Smoking at First and Second Hand: Time to Act. Anesthesiology: The Journal of the American Society of Anesthesiologists. 2011;115(1):1–3.
8. Saha U. Tobacco interventions and anaesthesia: A review. Indian Journal of Anaesthesia. 2009;53(5):618–627.
9. Zaballos M, Canal MI, Martínez R, et al. Preoperative smoking cessation counseling activities of anesthesiologists: A cross-sectional study. BMC Anesthesiology. 2015;15(1):60.
10. Katznelson R, M.D., Beattie WS, M.D., Ph.D., F.R.C.P.C. Perioperative Smoking Risk. Anesthesiology: The Journal of the American Society of Anesthesiologists. 2011;114(4):734–736.
11. Woehlck HJ, Connolly LA, Cinquegrani MP, Dunning MB, 3rd, Hoffmann RG. Acute smoking increases ST depression in humans during general anesthesia. Anesthesia & Analgesia. 1999;89(4):856–860.
12. Grønkjær M, Eliasen M, Skov-Ettrup LS, et al. Preoperative Smoking Status and Postoperative Complications: A Systematic Review and Meta-analysis. Annals of Surgery. 2014;259(1):52–71.
13. Schwilk B, Bothner U, Schraag S, Georgieff M. Perioperative respiratory events in smokers and nonsmokers undergoing general anaesthesia. Acta Anaesthesiologica Scandinavica. 1997;41(3):348–355.
14. Chiswell C, Akram Y. Impact of environmental tobacco smoke exposure on anaesthetic and surgical outcomes in children: A systematic review and meta-analysis. Archives of Disease in Childhood. 2017;102(2):123–130.
15. Turan A, Mascha EJ, Roberman D, et al. Smoking and perioperative outcomes. Anesthesiology. 2011;114(4):837–846.

Obese patients are becoming more commonplace in the operating room with each passing year. By the year 2030, an estimated 86.3% of adults will be overweight, and another 51% will be obese. Of these, the American Society of Metabolic and Bariatric Surgery estimates that 24 million will be morbidly obese [1]. Obesity is classified at a BMI greater than 30 kg/m2, and morbid obesity, or extreme obesity, is defined as a BMI greater than 40 kg/m2. These patient present unique respiratory problems in the operating room such as increased work of breathing, difficulty with preoxygenation and induction, and complicated emergence and postoperative care.

Morbid obesity is responsible for several derangements in pulmonary physiology. Oxygen demand, carbon dioxide production, and alveolar ventilation are elevated because metabolic rate is proportional to body weight [2]. The excessive adipose tissue over the chest wall compounds this problem by reducing chest wall compliance while leaving pulmonary compliance intact, which increases work of breathing and oxygen demand [3]. Increased abdominal adiposity is also responsible for forcing the diaphragm cephalad, further worsening restrictive lung physiology [2]. For every unit of BMI increased over 30 kg/m2, the residual volume, total lung capacity, and vital capacity drop by 0.5% [4]. Because functional residual capacity may fall below the normal tidal volume of these patients, they will experience a larger amount of atelectasis, which causes ventilation perfusion mismatching. The above changes are significantly exacerbated in the supine and Trendelenburg positions [2].

These pulmonary complications can make for particularly challenging inductions. Many morbidly obese patients have comorbid obstructive sleep apnea (OSA) making them particularly susceptible to rapid desaturation. An apnea hypopnea index greater than 30 implies severe OSA and is a predictor of rapid desaturation. Additionally, following induction of anesthesia, morbidly obese patients are more likely to derecruit gas exchange units, which exacerbates the likelihood of desaturation [5]. Preoxygenation with 100% FiO2 and a CPAP of at least 10cm H20 have been shown to improve PaO2 prior to induction and lengthen apnea time. After induction, CPAP of 10-12 cm H2O can be used to reduce atelectasis throughout the case, but care must be taken to prevent potential hypotension that results from increasing intrathoracic pressure [6].

Prior to extubation, neuromuscular blockade should be fully reversed [7]. Once spontaneous ventilation has resumed, morbidly obese patients can be maintained on pressure support. Extubation can be performed once a patient demonstrates adequate strength via sustained tetanus on nerve stimulator or adequate performance of the 5-second head lift. They should also adequately follow commands prior to extubation. Patients preparing for extubation should be placed in the trunk-up head-up position to improve oxygenation and decrease work of breathing. Immediately following extubation, pressure support or CPAP may be delivered via face mask in a similar fashion to induction preoxygenation [8].

In caring for morbidly obese patients post-operatively, respiratory and ventilatory concerns are at the forefront. The risk of postoperative hypoxia is increased in these patients, especially when there is preoperative hypoxia or with surgery involving the thorax or upper abdomen. An obese patient should remain intubated until there is no doubt that an adequate airway and tidal volume will be maintained, neuromuscular blockers are completely reversed, and the patient is awake [2]. In the post-anesthesia care unit (PACU), morbidly obese patients should have continuous pulse oximetry until they can demonstrate adequate oxygenation while unstimulated. A high level of suspicion should be maintained for hypoventilation, and the threshold for administering an oral airway should be low. If arousal and oral airway are inadequate to support the patient, it is reasonable to use non-invasive ventilation to prevent reintubation. While data is conflicting, there is a possible benefit to using incentive spirometry for the first two hours post-op to improve oxygenation [9]. Additionally, like in preinduction and extubation, there is a benefit to keeping morbidly obese patients upright in the PACU.

The respiratory changes in morbidly obese patients demand careful consideration of their physiology, induction, emergence, and postoperative care. Induction of anesthesia requires particular care for preoxygenation that other patients would not require. Emergence from anesthesia in the morbidly obese requires stricter adherence to extubation criteria. And, finally, post-operative care requires greater vigilance for hypoxia than in typical patients. As the population of obese and morbidly obese patients continues to grow, we will have to become more accustomed to recognizing and treating these respiratory complications in the operating room.

References
1. Ogden, C.L., et al., Prevalence of obesity among adults: United States, 2011-2012. NCHS data brief, 2013(131): p. 1-8.
2. Morgan, G.E., M.S. Mikhail, and M.J. Murray, Clinical anesthesiology. 4th ed. 2006, New York: Lange Medical Books/McGraw Hill, Medical Pub. Division. xiv, 1105 p.
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