Atrial fibrillation is a medical condition that affects roughly 33.5 million people worldwide [1]. Underlying cardiac conditions such as hypertension and coronary heart disease, which are common in developed countries, are risk factors for this condition. In lower income countries, rheumatic heart disease is associated with a higher incidence of atrial fibrillation, though rates are decreasing worldwide due to access to antibiotics. A later stage treatment approach for atrial fibrillation is ablation, with the assistance of anesthesia.

The pathophysiology of atrial fibrillation involves rapid firing from a single focus in the atria that triggers a change in heart rate and rhythm. The most common location is from the pulmonary veins, which can be targeted with catheter ablation. Treatment is focused on prevention of future episodes in addition to prevention of thromboembolism. First line treatment for atrial fibrillation is rate or rhythm control with oral medications such as beta-blockers or amiodarone. Thromboembolism risk is reduced with a direct oral anticoagulant.

If patients continue to remain symptomatic with recurrent episodes of atrial fibrillation despite medication, ablation is a highly effective procedural technique that can be considered. It is associated with 70-75% of patients being symptom-free after 1 year with 4% risk of major complications like stroke, cardiac perforation, or damage to the surrounding structures, such as the esophagus and phrenic nerve [2]. Electrophysiology evaluation is used to determine the location of myocardial tissue which is most responsible for the repetitive firing. An electroanatomical map is made, creating a 3-D representation of the patient’s heart to determine where the physician will use radiofrequency energy, cryothermal energy, or laser balloon to ablate myocardial tissue [2].

Cardiac ablation is a technique that is highly dependent on the practicing physician, with variability in duration of the procedure and the type of ablative energy used. The anesthesia used for atrial fibrillation ablation is highly important as this procedure is associated with significant risks. Conscious sedation with fentanyl and midazolam used to be the most common technique until studies comparing conscious sedation against general anesthesia found lower rates of recurrence and pulmonary vein reconnection with general anesthesia [3]. New retrospective cohort studies comparing monitored anesthetic care (MAC) vs. general anesthesia (GA) demonstrated MAC was independently associated with shorter total laboratory time due to reducing non-procedure time with no significant changes in freedom from documented atrial fibrillation, atrial flutter, atrial tachycardia and no significant difference in complication rates [4,6].

Despite this evidence, in a 2021 retrospective review, researchers demonstrated GA was still the most common mode of sedation for 54,231 patients who underwent cardiac ablation in the U.S., with 94% of patients receiving general anesthesia and only 6% receiving monitored anesthetic care (MAC) [5]. Patients who received MAC were more likely to be >80 years old, female, and have American Society of Anesthesiologist physical status > III. MAC cases were mostly done in Northeast urban hospital centers.

Current literature demonstrates that MAC is a safe anesthetic option for atrial fibrillation ablation that is not currently used widely in the United States. Due to its benefits, including shorter time in the laboratory with equitable outcomes to general anesthesia, more anesthesiologists may choose to use MAC over GA in the future.

References 

1. Lip GYH, Brechin CM, Lane DA. The global burden of atrial fibrillation and stroke: a systematic review of the epidemiology of atrial fibrillation in regions outside North America and Europe. Chest. 2012 Dec;142(6):1489-1498. doi: 10.1378/chest.11-2888. PMID: 22459778. 
2. Oral H, Knight BP, Ozaydin M, Tada H, Chugh A, Hassan S, Scharf C, Lai SW, Greenstein R, Pelosi F Jr, Strickberger SA, Morady F. Clinical significance of early recurrences of atrial fibrillation after pulmonary vein isolation. J Am Coll Cardiol. 2002 Jul 3;40(1):100-4. doi: 10.1016/s0735-1097(02)01939-3. PMID: 12103262.
3. Price A, Santucci P. Electrophysiology procedures: weighing the factors affecting choice of anesthesia. Semin Cardiothorac Vasc Anesth. 2013 Sep;17(3):203-11. doi: 10.1177/1089253213494023. Epub 2013 Jul 3. PMID: 23827944. 
4. Dada RS, Hayanga JWA, Woods K, Schwartzman D, Thibault D, Ellison M, Schmidt S, Siddoway D, Badhwar V, Hayanga HK. Anesthetic Choice for Atrial Fibrillation Ablation: A National Anesthesia Clinical Outcomes Registry Analysis. J Cardiothorac Vasc Anesth. 2021 Jan 5:S1053-0770(20)31393-8. doi: 10.1053/j.jvca.2020.12.046. Epub ahead of print. PMID: 33518460. 
5. Wasserlauf J, Knight BP, Li Z, et al. Moderate Sedation Reduces Lab Time Compared to General Anesthesia during Cryoballoon Ablation for AF Without Compromising Safety or Long-Term Efficacy. Pacing Clin Electrophysiol 2016; 39:1359. doi: 10.1111/pace.12961. Epub 2016 Nov 10. PMID: 27747896. 
6. Kuck KH, Brugada J, Fürnkranz A, et al. Cryoballoon or Radiofrequency Ablation for Paroxysmal Atrial Fibrillation. N Engl J Med 2016; 374:2235. doi: 10.1056/NEJMoa1602014. Epub 2016 Apr 4. PMID: 27042964. 

On January 1^st, 2022, the Biden administration’s “No Surprises Act” will be implemented in medical practices throughout America. The bill intends to protect patients from additional unanticipated medical bills following treatment while also establishing an independent dispute resolution for physicians to demand fair payment from health insurers. While the legislation is a promising step towards greater clarity on the financial component of healthcare, there remain some uncertainties about how this change will alter the ever-complicated relationship between physicians and health insurers. To this end, the American Society of Anesthesiologists (ASA) generated a list of recommendations for the implementation of the No Surprises Act.

The recommendations are included in an 11-page document addressed to the U.S. Department of Health and Human services, the U.S. Department of Labor, and the U.S. Department of Treasury, and are organized into five key categories: independent dispute resolution, qualifying payment amount and initial payment, patient engagement, interaction with state laws, and auditing. The ASA requests in particular that the process for independent dispute resolution be transparent by weighing all factors equally in the determination of payment and explicitly stating an intention to do so. According to the document, these factors include:

“the QPA, any additional information requested, the provider or facility’s level of training and experience, and the parties’ market shares, among other factors…We believe it is necessary for the Departments to be specific as to these considerations so the IDR process is standardized and does not vary significantly from one entity to the next. Even in the best of circumstances, these factors are subjective and will be assessed differently by each arbiter.”[1]

The list of recommendations also includes a demand for active commitment towards the reduction of biases in the settlement of payment disputes.

Moreover, the ASA requests that calculations of insurer’s median in-network amounts are done both accurately and fairly. The letter mentions the number of variables that can affect the cost of healthcare dramatically, including zip code, specialty, physician’s level of training, the frequency of payments, and several other factors. According to the ASA, the No Surprises Act does not specify its plans to determine median in-network amounts, and to not consider these factors would result in inaccurate payments and provide ample opportunity for healthcare insurers to underpay physicians.

One of the final notable components of the ASA’s requests is the demand that physicians be able to access the federal independent dispute resolution process. The ASA argues that in states where similar legislation to the No Surprises Act is already being implemented, the interaction between state and federal law would place too much strain on physicians. The letter states:

“We are concerned that the interaction of these federal and state frameworks will result in a patchwork scheme that creates tremendous uncertainty about which laws apply, placing the burden on parties to analyze which regulatory scheme they fall under. We believe this is asking too much of providers and patients. Providers’ primary concern is patient care and patients’ primary concern is obtaining the care needed to promote good health. We urge the Department to never lose sight of these important objectives.”¹

While the No Surprises Act has the potential to change the landscape of healthcare payment for both patient and physician alike, there remains the need for increased clarity. The ASA’s recommendations offer an actionable template for equitable implementation.

References

[1] ASA Makes Recommendations to Biden Admin: Implement ‘No Surprises Act’ Equitably Without Improper Advantage to Health Insurers. (2021). Retrieved from https://www.asahq.org/about-asa/newsroom/news-releases/2021/06/asa-makes-recommendations-to-implement-no-surprises-act-equitably

Mosquitos are a common vector for deadly diseases in humans, including malaria and dengue fever. Their capacity for disease transmission makes them dangerous to human populations, resulting in mosquitoes being responsible for millions of deaths per year (Ito et al. 2002). There have been substantial efforts to reduce mosquitos’ populations, from insecticide to removing pools of still water (Ito et al 2002). However, mosquito populations have persisted, and they have continued to spread disease. Insecticide resistance in mosquitoes makes controlling mosquito populations difficult, causing a need for alternative methods to reduce mosquito-borne disease transmission. Recent advances have led scientists to research the effectiveness of a modification that limits the ability of mosquito populations to get infected themselves, rather than limiting the spread of mosquitoes themselves.

Viral disease spread was significantly reduced in mosquito populations that were infected with Wolbachia pipientis (wMel), an inherited intracellular bacterium which infects many insects (Utarini et al. 2021). The wMel bacteria causes the mosquito to be less susceptible to dengue virus than non-modified mosquitoes. A previous study in 2013 showed wMel infected mosquitos were less likely to transmit dengue, however, the impact on human disease transmission was still unknown. In an Indonesian study, areas with wMel mosquito populations had reduced 77% of viral dengue cases, compared to areas with control populations (Utarini et al. 2021).

This study showed that modified mosquitoes can compete in natural environments. Additionally, the reduced vector capacity had tangible impacts on communities. The wMel versus non-modified population disparity in dengue cases shows how effective targeted infection of mosquitoes can be in controlling mosquito-borne diseases in human populations.

Similarly, control of parasitic diseases spread by mosquitoes have been hindered by an inability to control mosquito populations. Malaria, a disease caused by infection by Plasmodium parasites, has evaded many tools designed to limit its spread. New understanding of the gut’s role in the immune system has provided a new method to limit the transmission of malaria (Pike et al. 2017).

Researchers genetically modified mosquitoes create a peptide to inhibit Plasmodium development, specifically in the midgut. This genetic modification reduced the vector capacity of mosquitoes; however, it did not affect the overall fitness (Pike et al. 2017). Another study of genetically modified mosquitoes revealed the genetic modification is inheritable in mosquitoes and the resistance to the malaria parasite persisted through at least ten generations (Ito et al. 2002).

Genetic modification of mosquitoes can reduce transmission for diseases caused by mosquito-borne pathogens. This is important because genetic transmission can be effective in addressing a wide array of mosquito-borne diseases. While each situation would require specific knowledge of what genetic modification to create in the mosquitoes to limit disease control, this research is providing a new standard in how to control vector disease spread.

Genetic modification is a new method to address the significant issue of mosquito-borne diseases. It directly targets the vector capacity of mosquitoes, allowing for disease control at the source. Additionally, existing genetic modifications have been proven to be inheritable. This would allow the mosquito populations to naturally maintain resistance to known diseases. If genetic modification of mosquitoes becomes common practice, this would significantly lower the efforts needed to maintain a genetically modified mosquito population.

References

Ito, J., Ghosh, A., Moreira, L., et al. Transgenic anopheline mosquitoes impaired in transmission of a malaria parasite. Nature 417, 452–455 (2002). https://doi.org/10.1038/417452a

Pike, A., et al. “Changes in the Microbiota Cause Genetically Modified Anopheles to Spread in a Population.” Science, vol. 357, no. 6358, Sept. 2017, p. 1396, doi:10.1126/science.aak9691.

Utarini, A., et al. “Efficacy of Wolbachia-Infected Mosquito Deployments for the Control of Dengue.” New England Journal of Medicine, vol. 384, no. 23, Massachusetts Medical Society, June 2021, pp. 2177–86. doi:10.1056/NEJMoa2030243.

Residual paralysis is a prevalent yet under-recognized issue in perioperative medicine. Residual paralysis occurs when the effects of a neuromuscular blocking agent persist into the surgical recovery period. This complication has been associated with increased risk of critical respiratory events, postoperative pulmonary complications, coma, and patient death [1,2]. Additionally, certain populations are more susceptible to residual paralysis, particularly the elderly. A recent American study reported that up to 57.7 percent of older patients experience residual paralysis following surgery [3]. In order to mitigate associated risks, it is recommended that physicians perform perioperative quantitative neuromuscular monitoring on patients who are more susceptible to residual paralysis.

Quantitative neuromuscular monitoring involves transcutaneous stimulation using the train-of-four (TOF) or post-tetanic count (PTC) pattern, depending on the depth of the neuromuscular block. Following TOF stimulation, one can measure the number of elicited muscular contractions as well as the ratio of the fourth to the first twitch response. Quantitative measurements of twitch force, acceleration, velocity, or compound muscle action potential can be taken using mechanomyography, acceleromyography (AMG), kinemyography, and electromyography (EMG), respectively. Today, most clinics have access to an AMG monitoring device [4]. Importantly, AMGs require additional normalization to the control TOF ratio for increased accuracy, which can be achieved by measuring a baseline value before administration of a neuromuscular blocking drug [5]. Though EMG devices are less common, they are not affected by changes in muscle contractility nor temperature, making them the gold standard of quantitative neuromuscular monitoring according to Manfred et al. [4].

Once the patient has been subjected to quantitative neuromuscular measurements, physicians may use the resulting data to make pertinent clinical decisions. If the measurements indicate residual neuromuscular paralysis, then reversal of the neuromuscular block may be necessary. This can be accomplished by either waiting for the patient’s neuromuscular function to return spontaneously (which often involves prolonged recovery times and continuous monitoring) or through pharmacological intervention. Some of the most common neuromuscular block reversal agents are acetylcholinesterase inhibitors, which inhibit the breakdown of the muscle-stimulating neurotransmitter acetylcholine. Since this methodology requires a minimal threshold of acetylcholine already in the synaptic cleft to be effective, this option is only optimal in cases where minimal residual paralysis remains. If the persistent neuromuscular block is severe, more rigorous intervention may be needed: for example, the modified cyclodexterine sugammadex has been shown to sequester and encapsulate steroidal muscle relaxants for renal excretion, thus reducing their presence in muscle tissue and reversing paralytic effects [6,7]. Sugammadex is therefore useful in both moderate and extreme cases of residual neuromuscular paralysis.

In sum, quantitative neuromuscular measurements can be used to effectively identify postoperative residual paralysis, thus allowing physicians to make informed clinical decisions and improving patient outcomes. It is therefore of great clinical interest for anesthesia providers to perform quantitative neuromuscular monitoring following intensive surgical procedures, particularly in patients that are at a high-risk for persistent paralysis. Moreover, it is anticipated that this type of post-surgical monitoring will become increasingly integrated into standard care in the years to come.

References

1. Murphy GS, Szokol JW, Marymont JH, Greenberg SB, Avram MJ, Vender JS. Residual neuromuscular blockade and critical respiratory events in the postanesthesia care unit. Anesth Analg 2008;107:130-7. doi: 10.1213/ane.0b013e31816d1268
2. Berg H, Roed J, Viby-Mogensen J, Mortensen CR, Engbaek J, Skovgaard LT, Krintel JJ. Residual neuromuscular block is a risk factor for postoperative pulmonary complications: A prospective, randomised, and blinded study of postoperative pulmonary complications after atracurium, vecuronium and pancuronium. Acta Anaesthesiol Scand 1997;41:1095-103. doi: 10.1111/j.1399-6576.1997.tb04851.x
3. Murphy GS, Szokol JW, Avram MJ, Greenberg SB, Shear TD, Vender JS, Parikh KN, Patel SS, Patel A. Residual Neuromuscular Block in the Elderly: Incidence and Clinical Implications. Anesthesiology 2015;123:1322-36. doi: 10.1097/ALN.0000000000000865
4. Manfred B, Matthias E, Heidrun Lewald. Safe and Efficient Anesthesia: The Role of Quantitative Neuromuscular Monitoring. Advances in Patient Safety. 2020. http://advancesinpatientsafety.org/assets/ge_article-new.pdf
5. Suzuki T, Fukano N, Kitajima O, Saeki S, Ogawa S. Normalization of acceleromyographic train-of-four ratio by baseline value for detecting residual neuromuscular block. Br J Anaesth 2006;96:44-7. doi: 10.1093/bja/aei273
6. Kaufhold N, Schaller SJ, Stauble CG, Baumuller E, Ulm K, Blobner M, Fink H. Sugammadex and neostigmine dose-finding study for reversal of residual neuromuscular block at a train-of-four ratio of 0.2 (SUNDRO20). Br J Anaesth 2016;116:233-40. doi: 10.1093/bja/aev437
7. Schaller SJ, Fink H, Ulm K, Blobner M. Sugammadex and neostigmine dose-finding study for reversal of shallow residual neuromuscular block. Anesthesiology 2010;113:1054-60. doi: 10.1097/ALN.0b013e3181f4182a

In 1997, the U.S. Congress passed the Balanced Budget Act, which was meant to limit Medicare-based funding to residency programs and cap the number of residency spots available to medical school graduates [1]. As a result of these residency caps — and in spite of the adjustments made by the Balanced Budget Refinement Act of 1999, which marginally increased residency funding — federal funding for medical residencies has not kept pace with the number of residents needed to care for a growing and aging population.

Between 2001 to 2010, funding for medical residencies increased just 0.9% [2]. One survey, intending to track changes in residency numbers across specialties before and after the 1997 BBA, used the annual National GME Census as its data source. The census, a joint project of the Association of American Medical Colleges and the American Medical Association, tracks the numbers and specialties of U.S. medical residents, as well as those residents’ demographic information. The study found that, following a temporary halt in residency-program growth after 1997, programs began expanding again between 2002 and 2007, with an 8% net increase between 1997 and 2007 [3].

Indeed, in the aforementioned survey, anesthesiology residencies grew faster than almost any other specialty, with an increase of 9.1% between 2002 and 2007 [3]. The data on growth in anesthesia residency programs proved unexpected, after a number of analyses in the late 1990’s and early 2000’s predicted shortages in anesthesiologists: for instance, one study estimated a shortfall of between 1,100 and 3,800 anesthesiologists in 2002 [4]. Meanwhile, specialties like primary care saw marked decreases in the number of residency positions available following the passage of the Balanced Budget Act. According to one analysis, the decade between 1998 and 2008 saw a net loss of 390 positions for first-year family medicine residents [5]. However, these changes did not follow the passage of the Balanced Budget Act immediately, and thus cannot necessarily be linked directly to its passage: a survey of 478 family medicine practices found that, in the two years following the act’s passage and the subsequent changes to residency funding, there was a relatively minor net reduction of 82 residents [6].

While the Balanced Budget Act caps funding for residencies, researchers have predicted that certain subspecialties may actually see a shortage of residents in the coming years, and in some cases may be unable to fill open residency slots. This discrepancy is predicted even in spite of growing enrollment numbers at existing U.S. medical schools—the number of U.S. medical school applicants increased 18% between the 2020 and 2021 academic years, perhaps in part due to the COVID-19 pandemic [7]. Still, one study has predicted that 22,280 individuals will graduate from American medical schools in 2026, matching into a predicted 29,880 residency positions (given the yearly growth rate of 2.55% in U.S. residency slots from 2006 to 2015). If trends continue as calculated in this study, there will not be a shortage of residency positions overall, though highly competitive specialties may encounter a different situation [8].

While the Balanced Budget Act and subsequent Balanced Budget Refinement Act limited government funding for medical residencies, these residency caps control neither the number of medical school graduates per year, nor the chosen specialties and subspecialties of those graduates when matching into residency programs. As a result, certain specialties may encounter a shortage of residents to fill funded residency positions, while others may encounter a lack of available positions for qualified medical school graduates.

References 

[1] Havidich, Jeana E., et al. “The Effect of Lengthening Anesthesiology Residency on Subspecialty Education.” Anesthesia & Analgesia, vol. 99, no. 3, 2004, pp. 844–856., doi:10.1213/01.ane.0000130258.38402.2e.  

[2] Iglehart, John K. “The Residency Mismatch.” New England Journal of Medicine, vol. 369, no. 4, 2013, pp. 297–299., doi:10.1056/nejmp1306445.  

[3] Salsberg, Edward. “US Residency Training Before and After the 1997 Balanced Budget Act.” JAMA, vol. 300, no. 10, 2008, p. 1174., doi:10.1001/jama.300.10.1174.  

[4] Schubert, Armin et al. “An updated view of the national anesthesia personnel shortfall.” Anesthesia & Analgesia, vol. 96,1 (2003): 207-14, table of contents. doi:10.1097/00000539-200301000-00043 

[5] Weida, Nicholas A, et al. “Loss of Primary Care Residency Positions Amidst Growth in Other Specialties.” American Academy of Family Physicians, vol. 82, no. 2, 15 July 2010, p. 121. 

[6] Schneeweiss, Ronald et al. “The effects of the 1997 Balanced Budget Act on family practice residency training programs.” Family Medicine, vol. 35,2 (2003): 93-9. 

[7] “Enrollment Up at U.S. Medical Schools.” AAMC, Association of American Medical Colleges, 16 Dec. 2020. https://www.aamc.org/news-insights/press-releases/enrollment-us-medical-schools

[8] Hayek, Sarah, et al. “Ten Year Projections for US Residency Positions: Will There Be Enough Positions to Accommodate the Growing Number of U.S. Medical School Graduates?” Journal of Surgical Education, vol. 75, no. 3, 2018, pp. 546–551., doi:10.1016/j.jsurg.2017.08.021.