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Despite their demonstrated efficacy as sedation and analgesics, propofol and ketamine can result in adverse events [1]. Propofol can lead to hypotension, respiratory depression, hypoventilation, and loss of airway reflexes [2]. Conversely, ketamine does not risk the compromise of a patient’s airway reflexes, but it can cause hypertension, emergence delirium, vomiting, and tachycardia [2]. Ketamine can also impede the central nervous system [1]. To avoid the complications associated with each medication, researchers developed ‘ketofol’ as a combination of propofol and ketamine [1].

At first glance, ketofol appeared to be an effective replacement for ketamine and propofol. In 1999, Friedberg conducted a large meta-analysis of 2,059 operations performed on 1,264 patients anesthetized using combination propofol and ketamine [3]. None of the patients reported hallucinations, uncontrolled pain, vomiting, and nausea, and all of them were satisfied with their anesthetic regimen [3]. The study concluded that ketofol is a safe and effective anesthetic [3]. More recently, Slavik and Zed retrospectively analyzed 23 studies, all of which were centered on the efficacy of propofol and ketamine in combination [1]. They concluded that there was not substantial literature to demonstrate that ketofol evades the adverse cardiovascular events associated with ketamine and propofol [1]. Furthermore, ketamine-propofol did not appear to provide better analgesia than propofol alone [1]. While these findings do not necessarily contradict Friedberg’s conclusion, they certainly demonstrate the need for more research on ketofol.

For anesthesia providers considering using ketofol during an operation, knowledge of the appropriate ratio to administer is essential. Several studies have compared different ratios among themselves, as well as to anesthetic monotherapies, such as propofol alone [4]. One such study drew a comparison between 2:1, 3:1, and 4:1 propofol-ketamine combinations; propofol alone; and a propofol-fentanyl combination [4]. All of the ketofol mixtures provided patients with effective analgesia [4]. However, the 3:1 and 4:1 mixtures led to especially quick recovery and discharge times [4]. Additionally, the 4:1 mixture was responsible for the lowest incidences of postoperative dizziness and respiratory depression among the propofol-ketamine mixtures [4]. While these are the results of only one experiment, they could help guide physicians toward the ideal ratio with which to create ketofol.

Despite its uncertain benefits, ketofol has already found meaningful application in hospital emergency departments (ED). Phillips et al. studied the efficacy of combination ketamine and propofol in an ED during brief procedures, such as fracture manipulation [5]. Of the 28 patients studied, none required intervention or underwent respiratory depression [5]. Compared to the propofol group, the ketofol group was closer to their target bispectral index monitoring score and experienced less hypotension [5]. Willman and Andolfatto also encountered promising results when analyzing the cases of 114 patients who received ketofol in an ED [6]. No patient experienced vomiting or hypotension, and 96.5% of patients did not require additional sedatives [6]. Together, these results suggest there may be cardiovascular benefits, among others, to the use of ketofol as a sedative.

Still, ketofol does not seem so promising in all contexts. One such context is pediatrics. A recent meta-analysis of 29 studies sought to determine the efficacy of ketofol in operations conducted on children [7]. Hayes et al. did identify reduction of some risks due to ketofol–including apnea, hypotension, and bradycardia [7]. Yet, they also found that ketofol may increase children’s risk of respiratory adverse events, hypertension, and tachycardia [7]. Another study did not find a significant difference in sedative quality between ketofol and ketamine, with adverse events occurring at comparable frequencies [2]. Whether these results are the symptoms of imperfect ratios, or indicative of a greater failure on the part of ketofol, warrants continued investigations into the mechanisms of combination propofol and ketamine.

References

[1] V. C. Slavik and P. J. Zed, “Combination Ketamine and Propofol for Procedural Sedation and Analgesia,” Pharmcotherapy, vol. 27, no. 11, p. 1588-1598, January 2012. [Online]. Available: https://doi.org/10.1592/phco.27.11.1588.

[2] Y. Hu, W. Xu, and F. Cao, “A meta-analysis of randomized controlled trials: combination of ketamine and propofol versus ketamine alone for procedural sedation and analgesia in children,” Internal and Emergency Medicine, vol. 14, p. 1159-1165, September 2019. [Online]. Available: https://doi.org/10.1007/s11739-019-02173-6. 

[3] B. L. Friedberg, “Propofol-ketamine technique: Dissociative anesthesia for office surgery (A 5-year review of 1264 cases),” Aesthetic Plastic Surgery, vol. 23, no. 1, p. 70-75, January-February 1999. [Online]. Available: https://doi.org/10.1007/s002669900245.

[4] S. Amornyotin, “Ketofol: A Combination of Ketamine and Propofol,” Journal of Anesthesia & Critical Care, vol. 1, no. 5, p. 1-3, January-February 1999. [Online]. Available: https://doi.org/10.15406/jaccoa.2014.01.00031.

[5] W. Phillips et al., “Propofol Versus Propofol/Ketamine for Brief Painful Procedures in the Emergency Department: Clinical and Bispectral Index Scale Comparison,” Journal of Pain & Palliative Care Pharmacotherapy, vol. 24, no. 4, p. 349-355, December 2010. [Online]. Available: https://doi.org/10.3109/15360288.2010.506503.

[6] E. V. Willman and G. Andolfatto, “A Prospective Evaluation of “Ketofol” (Ketamine/Propofol Combination) for Procedural Sedation and Analgesia in the Emergency Department,” Annals of Emergency Medicine, vol. 49, no. 1, p. 23-30, January 2007. [Online]. Available: https://doi.org/10.1016/j.annemergmed.2006.08.002.

[7] J. A. Hayes et al., “Safety and Efficacy of the Combination of Propofol and Ketamine for Procedural Sedation/Anesthesia in the Pediatric Population: A Systematic Review and Meta-analysis,” Anesthesia & Analgesia, vol. 132, no. 4, p. 979-992, April 2021. [Online]. Available: https://doi.org/10.1213/ANE.0000000000004967.

The intellectual output of an engineer-obstetrician duo, ultrasound was first used clinically as a medical imaging technology in 1956, becoming commonplace in the 1960’s, and has since established itself as a cornerstone medical imaging procedure. Key advantages over other imaging modalities include its low cost of manufacturing and use, noninvasive nature, easy visualization of hemodynamics and tissue properties, compatibility with real-time dynamic assessment, and ease of use in the form of portable ultrasound devices ¹. Recently, a number of advances in musculoskeletal ultrasound imaging, in particular, have galvanized its use across multiple clinical applications ².

First, Doppler ultrasound has been critical for the diagnosis and monitoring of inflammatory arthropathies and the assessment of neoplasms, tendinopathies, and neuropathies. For example, Doppler ultrasound can differentiate between active synovitis and chronic fibrotic synovium, as the former appears as hyperemia ³, and, in oncologic imaging, can clearly distinguish benign from malignant tumors ⁴.

However, traditional Doppler ultrasound remains limited by its inability to clearly visualize microvascular flow, since its algorithm filters lower velocity elements to reduce clutter. Clearly assessing microvascular flow is key, though, to diagnosing early inflammatory processes and neoplastic angiogenesis ^4,5. To this end, multiple advanced ultrasound methods have been developed. First, contrast-enhanced ultrasound, combining microbubble-based intravenous contrast agents with traditional ultrasound, can, unlike previous Doppler ultrasound methods, display blood perfusion and identify capillary-level neovascularization ⁶. Second, another distinct Doppler technique, incorporating a unique motion suppression algorithm that isolates and eliminates clutter, can also enable the visualization of low flow microvasculature ⁷.

Most recently, ultra-high frequency transducers, reaching frequencies of 20-70 MHz, far exceeding the traditional 12-18 MHz range, have also been used to visualize increasingly granular anatomical detail. As such, individual fascicles may now be distinguished using the newest high-frequency ultrasound technology ⁸. Clinically, this first means that ultrasound-guided neurosurgical procedures can spare nerve fascicles, presenting clear advantages over conventional ultrasound or magnetic resonance imaging ⁹. Second, various musculoskeletal features can be accurately measured. Tendons are easily seen, thereby enabling, for example, the identification of pulleys during ultrasound-guided treatments, resulting in safer surgeries ¹⁰. Capsular ligaments, retinacula, and fasciae, all involving millimeter-diameter mesenchymal structures, are now also distinctly visible ². Finally, this new level of precision means that ultrasounds can be used for the early detection of neoplastic masses several millimeters in size. Importantly, however, as the frequency of the ultrasound beams increase, penetration decreases. Thus, these ultrahigh frequency transducers are best suited for assessing for superficial structures.

Finally, elastography can now be used to investigate and possibly heal musculoskeletal system function. To this end, assessing stiffness of nerves and tissue around nerves in fibro-osseous tunnels can be done either by traditional strain or shear-wave elastography techniques ¹¹.

Ultrasound is less physically and economically demanding on patients and has been greatly improving the quality of medical care. Given the rapidity of advances in ultrasound technologies, there is a clear need to standardize the execution and reporting of different associated techniques. Nonetheless, ultrasound continues to represent an indispensable diagnostic imaging modality in clinical settings, with likely many exciting additional future prospects.  

References

1.        Matsuzaki M. The latest technology of musculoskeletal ultrasonography: iterative revolution. J Med Ultrason. 2017. doi:10.1007/s10396-017-0799-0

2.        van Holsbeeck M, Soliman S, van Kerkhove F, Craig J. Advanced musculoskeletal ultrasound techniques: What are the applications? Am J Roentgenol. 2021. doi:10.2214/AJR.20.22840

3.        Aggarwal R, Aggarwal V. High-Resolution musculoskeletal ultrasound in India: The present perspective and the future. Indian J Rheumatol. 2018. doi:10.4103/0973-3698.238196

4.        Jiang Z Zhen, Huang Y Hua, Shen H Liang, Liu X Tian. Clinical Applications of Superb Microvascular Imaging in the Liver, Breast, Thyroid, Skeletal Muscle, and Carotid Plaques. J Ultrasound Med. 2019. doi:10.1002/jum.15008

5.        Arslan S, Karahan AY, Oncu F, Bakdik S, Durmaz MS, Tolu I. Diagnostic performance of superb microvascular imagingand other sonographic modalities in the assessment of lateral epicondylosis. J Ultrasound Med. 2018. doi:10.1002/jum.14369

6.        Qin S, Caskey CF, Ferrara KW. Ultrasound contrast microbubbles in imaging and therapy: Physical principles and engineering. Phys Med Biol. 2009. doi:10.1088/0031-9155/54/6/R01

7.        Yokota K, Tsuzuki Wada T, Akiyama Y, Mimura T. Detection of synovial inflammation in rheumatic diseases using superb microvascular imaging: Comparison with conventional power Doppler imaging. Mod Rheumatol. 2018. doi:10.1080/14397595.2017.1337288

8.        Cartwright MS, Baute V, Caress JB, Walker FO. Ultrahigh-frequency ultrasound of fascicles in the median nerve at the wrist. Muscle and Nerve. 2017. doi:10.1002/mus.25617

9.        Forte AJ, Boczar D, Oliver JD, Sisti A, Clendenen SR. Ultra-high-frequency Ultrasound to Assess Nerve Fascicles in Median Nerve Traumatic Neuroma. Cureus. 2019. doi:10.7759/cureus.4871

10.      Yang TH, Lin YH, Chuang BI, et al. Identification of the Position and Thickness of the First Annular Pulley in Sonographic Images. Ultrasound Med Biol. 2016. doi:10.1016/j.ultrasmedbio.2015.12.007

11.      Ooi CC, Malliaras P, Schneider ME, Connell DA. “Soft, hard, or just right?” Applications and limitations of axial-strain sonoelastography and shear-wave elastography in the assessment of tendon injuries. Skeletal Radiol. 2014. doi:10.1007/s00256-013-1695-3

Thousands of people suffer from substance abuse and addiction disorders all over the country and world. The typical policy response to this epidemic has been aimed at eradicating this behavior through policing and criminal justice action, and yet, no meaningful progress has been made¹. Many advocates and researchers have raised the question: is this all-or-nothing approach the right way to decrease drug use and its associated problems? Or is the middle ground, “harm reduction” approach more effective?

The philosophy of harm reduction has long since been considered controversial, because it values policy favoring pragmatism over total eradication¹. For example, harm reduction proponents operate under the assumption that IV drug abuse will endure, and that the focus should instead be on minimizing transmission of Hepatitis C and HIV. Another example is focusing on reducing potential opioid overdose by opening methadone clinics and having community access to Narcan, rather than eliminating harmful opioid use². The controversy surrounding harm reduction is also likely due in part to unclear definitions and messaging, however, public health experts believe that community-driven, evidence-based harm reduction efforts do have a net positive effect on the overall health of vulnerable populations1.

The first large, real harm reduction program was established in the 1980s, in Liverpool, and was targeted at reducing the prevalence of HIV in people using IV drugs². Program workers implemented the Mersey Model of Harm Reduction, which had three main principles: making contact with the population at risk (particularly those not already accessing healthcare), maintaining contact with those people, and making changes in their behavior². They offered a variety of services including needle exchanges, opioid substitution therapy, STD and HIV testing programs and outreach programs to reach as many people as possible in need of help². In the first two years, over 1000 people utilized these services and were responsible for a third of the methadone prescribed in England in that time period². Needle exchange programs and treatment units like the one in Liverpool were set up all over the region, and it was estimated that in the next five years, about 10,000 people were able to benefit from this model². Studies showed that the sharing of needles was significantly reduced in that area, and crime in Merseyside also went down during this time, particularly burglary and theft from vehicles, a reduction attributed to the methadone clinics set up by this program².

Harm reduction goes beyond IV drugs; an even more common problem is tobacco use, which is associated with many health risks³. Smokeless tobacco is the leading model of THR (tobacco harm reduction) today and has been endorsed by the American Council on Science and Health as being a 98% safer alternative to smoking³. Smokeless tobacco is not associated with an elevated risk of heart attack, hypertension, and GI symptoms when compared to smoking³. Smokeless tobacco has even been proven to be safer in pregnant women, and while all forms of nicotine should be avoided in pregnancy, smokeless tobacco offers less teratogenic risk than smoking cigarettes³. While more research needs to be done to solidify smokeless tobacco as a legitimate strategy for people who smoke, these preliminary results are promising³.

Harm reduction can be a difficult pill to swallow; should we as a society settle for “less bad” instead of “good?” However, if implemented in an evidence-based fashion, these programs and models have been shown to improve overall health and outcomes, and should be considered when making health policy decisions¹.

References 

1. Ball AL. HIV, injecting drug use and harm reduction: a public health response. Addiction, 2007; 12(5): 684-690. https://doi.org/10.1111/j.1360-0443.2007.01761.x 

2. Ashton JR, Seymour H. Public Health and the origins of the Mersey Model of Harm Reduction. International Journal of Drug Policy, 2010; 21(2): 94-96. https://doi.org/10.1016/j.drugpo.2010.01.004 

3. Rodu B. The scientific foundation for tobacco harm reduction, 2006-2011. Harm Reduction Journal, 2011; 8. https://doi.org/10.1186/1477-7517-8-19 

In the early days of the Covid-19 pandemic, ventilator shortages and their importance in the treatment of the disease brought renewed attention to mechanical ventilation. Ventilatory assistance has been used to help patients with airway injuries, lung damage and other conditions for centuries. However, the history of modern mechanical ventilators dates back to the mid-19^th century.  

The earliest mention of mechanical ventilation comes in the writings of Vesalius, a 16^th century academic. His writings on the human anatomy detailed a method of positive pressure ventilation and described a lifesaving procedure that today would be called a tracheotomy [1]. However, most of his research was hypothetical — it would take several centuries until a machine capable of mechanical ventilation was invented.  

The first mechanical ventilators were produced in the 1800s. The earliest mechanical ventilators worked by enclosing the patient in a box that contained negative pressure, which was then used to replace the patient’s respiration. In 1864, Alfred Jones created a prototype device wherein the patient’s seated body was enclosed within a sealed box. A plunger was used to create negative pressure, which would cause inhalation. When that plunger was released, the pressure would stabilize, causing exhalation [2].  

A few years later, in 1876, the first iron lung was built, but it was not widely used at first [1]. However, the poliomyelitis outbreak in the early 20^th century led to a widespread need for ventilators. The virus that causes the disease can attack the respiratory system, causing respiratory failure [3]. In 1929, an electrically-powered ventilator was built and sold by Drinker and Shaw. This became the standard for treating polio in the United States [4]. Later versions allowed nurses to access the patient. 

The first positive pressure ventilators were developed in the 1950s, spurred by a new, larger outbreak of polio. At first, these ventilators were non-invasive but, due to their efficacy, invasive positive pressure ventilators were soon the norm. The early generations of ICU ventilators also offered rudimentary monitoring capabilities, which allowed physicians to monitor the patient’s tidal volume and respiratory rate [5]. The third generation of ventilators would include more robust gas delivery systems, as well as additional alarm and monitoring functions.  

The current generation of ventilators is the result of more than five decades of research into positive pressure ventilators, as well as centuries of observations regarding mechanical ventilation. These ventilators offer advanced monitoring capabilities and a host of automated features. Likewise, they also offer newer modes of ventilation, including pressure-control ventilation, synchronized intermittent mandatory ventilation, and pressure-support ventilation (PSV) [6]. However, many of the hazards of invasive ventilators that marred the early years of the technology still exist. 

Even as positive pressure ventilators continue to dominate, the pandemic has led some researchers to question whether there is still a role for negative pressure ventilators. Unlike positive pressure ventilators, negative pressure ventilators tend to cost less and have a lower risk of complications. More recent proposals are also significantly smaller in size than the iron lungs of 20^th century. Regardless of the form of ventilation, future mechanical ventilators will undoubtably remain one of the most essential tools in anesthesiology, surgery, and intensive care. 

References 

[1] Slutsky, Arthur S. “History of Mechanical Ventilation. From Vesalius to Ventilator-Induced Lung Injury.” American Journal of Respiratory and Critical Care Medicine, vol. 191, no. 10, 2015, pp. 1106–1115., doi:10.1164/rccm.201503-0421pp.  

[2] The Evolution of “Iron Lungs”: 1928-1978. J.H. Emerson Co., 1978.  

[3] Wunsch, Hannah. “The Outbreak That Invented Intensive Care.” Nature, 2020, doi:10.1038/d41586-020-01019-y.  

[4] Maxwell, James H. “The Iron Lung: Halfway Technology or Necessary Step?” The Milbank Quarterly, vol. 64, no. 1, 1986, p. 3., doi:10.2307/3350003. 

[5] Kacmarek, R. M. “The Mechanical Ventilator: Past, Present, and Future.” Respiratory Care, vol. 56, no. 8, 2011, pp. 1170–1180., doi:10.4187/respcare.01420.  

[6] Jain, Rajnish K., and Srinivasan Swaminathan. “Anaesthesia Ventilators.” Indian Journal of Anaesthesia, vol. 57, no. 5, 2013, p. 525., doi:10.4103/0019-5049.120150.  

[7] Abughanam, Nada, et al. “Investigating the Effect of Materials and Structures for Negative Pressure Ventilators Suitable for Pandemic Situation.” Emergent Materials, vol. 4, no. 1, 2021, pp. 313–327., doi:10.1007/s42247-021-00181-x.  

In 1970, the interscalene or brachial plexus block was devised as a technique for administering regional anesthesia of the shoulder. This technique has evolved over time, accessing the brachial plexus first through a nerve stimulator and more recently through an ultrasound guided block¹.  

Administration of local anesthesia in shoulder surgery is made difficult by the emergence of the brachial plexus between the anterior scalene and middle scalene, and its subsequent, complicated descent and innervation of the shoulder and upper limb¹. Because of this, general anesthesia is often preferred during shoulder surgery¹. Interscalene block provides an option for regional anesthesia during surgery and, more commonly, is also used for preventing and managing postoperative pain¹. The interscalene block is the most common postoperative analgesic for shoulder arthroplasty, and the PROSPECT guidelines have named interscalene block as the first line treatment for pain after rotator cuff surgery⁵. It can be used successfully with adjuvant therapies as well; one study showed that dexmedetomidine, an alpha-2 receptor agonist, works synergistically with an interscalene block to reduce postoperative pain after arthroscopic rotator cuff repair³. Because this combination of therapies significantly decreases postoperative pain in shoulder surgery patients, it offers an alternative to opioids in pain management³.  

However, there are some important complications of this technique that should be considered. The local anesthetic could be spread to the phrenic nerve, the sympathetic ganglia or other tissues, causing hemi diaphragmatic paresis, Horner syndrome and hoarseness². Other acute reported complications include peripheral neuropathy caused by nerve injury and postoperative paresthesias, and while these were originally thought to be due to the block itself, researchers are investigating the possibility that they are caused by the interactions between the peripheral block and patient risk factors². Rarely, an interscalene block can cause spontaneous pneumothorax and seizures, although it is not generally considered to be a risk factor for these complications². Furthermore, the interscalene block has reportedly caused chronic complications in rare cases, such as carpal tunnel, prolonged paresthesia and loss of sensory function in the hand, and in one puzzling case, idiopathic neuropathy². The patient in question had an uncomplicated interscalene block combined with general anesthesia, and their symptoms spontaneously resolved in nine months².  

While this technique does not seem to cause long-term or unresolvable complications, the complications noted above have caused researchers to consider the use of other access techniques, such as the interscalene perineural catheter or the supraclavicular plexus block^2,4. One study in the European Journal of Anesthesiology performed a systematic review and meta-analysis on the efficacy of the supraclavicular plexus block in preventing postoperative pain compared to the interscalene block⁴. This study found that the two analgesics resulted in comparable pain scores, but that the supraclavicular block was associated with fewer adverse events⁴.  

Interscalene block has provided an avenue for managing pain in patients that have undergone shoulder surgery. Clinicians should investigate the use of interscalene block on a case by case basis and evaluate risk prediction based on individual patient health profiles.  

References 

1. Banerjee S, Acharya R, and Sriramka B. Ultrasound-Guided Inter-scalene Brachial Plexus Block with Superficial Cervical Plexus Block Compared with General Anesthesia in Patients Undergoing Clavicular Surgery: A Comparative Analysis. Anesthesia Essays and Researches, 2019; 13(1): 149-154. doi: 10.4103/aer.AER_185_18 

2. Borgeat A, Ekatodramis G, Kalberer F, Benz C. Acute and Nonacute Complications Associated with Interscalene Block and Shoulder Surgery: A Prospective Study. Anesthesiology, 2001; 95: 875-880. doi: 10.1097/00000542-200110000-00015 

3. Hwang JT, Jang JS, Lee, JJ et al. Dexmedetomidine combined with interscalene brachial plexus block has a synergistic effect on relieving postoperative pain after arthroscopic rotator cuff repair. Knee Surgery, Sports Traumatology, Arthroscopy, 2020; 28: 2343–2353. doi: 10.1007/s00167-019-05799-3 

4. Schubert AK, Dinges HC, Wulf H, Wiesmann T. Interscalene versus supraclavicular plexus block for the prevention of postoperative pain after shoulder surgery. European Journal of Anaesthesiology, 2019; 36: 427-435 doi: 10.1097/EJA.0000000000000988. 

5. Toma O, Persoons B, Pogatzki-Zahn, E, Van de Helde M, Joshi GP. PROSPECT guideline for rotator cuff repair surgery: systematic review and procedure specific postoperative pain management recommendations. Anaesthesia, 2019; 74(10): 1320-1331. doi: 10.1111/anae.14796 

D-dimer is the primary breakdown fragment of fibrin and is routinely used as a biomarker of fibrinolysis and coagulation [1]. Healthy individuals have low levels of circulating D-dimer, whereas elevated levels are frequently found in conditions associated with chronic inflammation and thrombosis [1]. Given that widespread microthrombi have been observed in multiple organ systems in patients with COVID-19, many recent studies have focused on the role of D-dimer in determining disease outcomes [1]. 

Elevated D-dimer levels have been linked to several adverse events, including thrombosis, critical illness, acute kidney injury, and all-cause mortality [1]. Patients with severe COVID-19 have a higher level of D-dimer than those with a mild infection [3]. A D-dimer level greater than 0.5 μg/ml is associated with severe infection in patients with COVID-19 [3]. Higher in-hospital mortality is associated with D-dimer levels greater than 3 μg/ml [3]. Markedly elevated D-dimer has also been linked to 28-day mortality in COVD-19 patients [3].  

The D-dimer test is commonly used in clinical practice to exclude a diagnosis of deep vein thrombosis (DVT), pulmonary embolism (PE), or disseminated intravascular coagulation (DIC) [2]. Elevated D-dimer levels indicate increased risk of abnormal blood clotting and are found in almost all patients with severe DVT [2,3]. A rise in D-dimer levels has also been associated with a higher mortality rate in community-acquired pneumonia [3]. The amount of D-dimer in the body can be measured using various commercial kits based on a monoclonal antibody [2]. The sensitivity of these D-dimer test kits ranges between 93% and 95% [2]. 

COVID-19 predisposes patients to thrombotic disease, both in venous and arterial circulation, due to excessive inflammation, platelet activation, endothelial dysfunction, and stasis [4]. Patients with COVID-19 infection are up to 25% more likely to experience thrombosis [2]. Elevated D-dimer levels are associated with the disease progression of COVID-19 and increased incidence of coagulopathy [3]. The levels of D-dimer in patients with COVID-19 admitted to the ICU has been reported to be significantly increased [3]. Patients with COVID-19 infections in the ICU are often preemptively treated with therapeutic anticoagulation in order to prevent future thrombotic events [5]. A 2020 study examined the incidence of thrombotic complications in 184 COVID-19 patients admitted to the ICU [5]. The results showed a 31% incidence of thrombotic complications, with PE ranking as the most frequent thrombotic complication [5]. 

There is also evidence to suggest that D-dimer may not only be a biomarker of hypercoagulability but also may participate in pathogenesis [1]. Fibrin degradation products have a direct procoagulant effect by inducing acute pulmonary dysfunction [1]. They also increase platelet aggregation, prostaglandin synthesis, complement activation, and initiation of chemotaxis and neutropenia [1]. Underlying conditions such as diabetes, cancer, stroke, and pregnancy may trigger an increase in D-dimer levels in COVID-19 patients [6]. 

 One of the most consistent hemostatic abnormalities associated with COVID-19 is increased D-dimer levels [4]. Although the cause of this elevation is uncertain, new data has indicated that a 3- to 4-fold rise in D-dimer levels is associated with poorer prognosis [4,6]. When treating patients with COVID-19, physicians should be aware of D-dimer level status and vigilant to signs of thrombotic complications [5]. 

References 

1. Berger, J., Kunichoff, D., Adhikari, S. et al. (2020). Prevalence and Outcomes of D-Dimer Elevation in Hospitalized Patients With COVID-19. Arteriosclerosis, Thrombosis, And Vascular Biology, 40(10), 2539-2547. doi:10.1161/atvbaha.120.314872 

2. Rostami, M., & Mansouritorghabeh, H. (2020). D-dimer level in COVID-19 infection: a systematic review. Expert Review of Hematology, 13(11), 1265-1275. doi:10.1080/17474086.2020.1831383 

3. Yu, H., Qin, C., Chen, M. et al. (2020). D-dimer level is associated with the severity of COVID-19. Thrombosis Research, 195, 219-225. doi:10.1016/j.thromres.2020.07.047 

4. Demelo-Rodríguez, P., Cervilla-Muñoz, E., Ordieres-Ortega, L. et al. (2020). Incidence of asymptomatic deep vein thrombosis in patients with COVID-19 pneumonia and elevated D-dimer levels. Thrombosis Research, 192, 23-26. doi:10.1016/j.thromres.2020.05.018 

5. Klok, F., Kruip, M., van der Meer, N. et al. (2020). Incidence of thrombotic complications in critically ill ICU patients with COVID-19. Thrombosis Research, 191, 145-147. doi:10.1016/j.thromres.2020.04.013 

6. Yao, Y., Cao, J., Wang, Q. et al. (2020). D-dimer as a biomarker for disease severity and mortality in COVID-19 patients: a case control study. Journal of Intensive Care, 8(1). doi:10.1186/s40560-020-00466-z 

In 2020, only 10.4% of medical school graduates were underrepresented minorities, despite comprising at least 33.4% of the United States population [1, 2]. Similarly, about 50% of the population are women, but women represented only 41% of medical school graduates [2]. This diversity issue is exacerbated among anesthesia professionals. Anesthesia professionals encompass people across a wide variety of roles, including nurse anesthetists, physician anesthesiologists, and anesthesiology fellows. Across these categories, women and non-white, non-Asian minorities remain even more underrepresented [2].  

Only 25% of the overall anesthesiology workforce is female [2]. The deficit of female involvement in the field is notable in several venues, from anesthesiology residencies to academic Grand Rounds [2, 3]. This exclusion from the opportunity to present one’s work inhibits women’s ability to advance in the field, perpetuating the problem [2]. In 2006-2007, women represented only 18.8% of American Board of Anesthesiology oral board examiners, 14% of full anesthesiology professors, 12.7% of academic anesthesiology chairs, and 10% of all medical school department chairs [4]. 

Lacking role models and mentors in the field, female medical students, fellows, and residents may be dissuaded or face diminished expectations concerning their career trajectory [2]. Therefore, connecting female anesthesia professionals with other women is important for retention [5]. Studies have also shown that female anesthesiologists are more likely to work part-time, get paid 25% less every year, and work fewer hours each week than their male counterparts [5]. Instituting equal salaries and adjusting workflow within the profession such that it is accommodating for women’s needs would help ensure that women keep climbing up the professional ladder [5]. 

In terms of underrepresented minorities (including African Americans, Native Americans, and Hispanics, but not Asians), there is an even greater disparity in terms of representation [2]. Compared to the relatively mild 10.4% of minority medical school graduates, the overall anesthesia workforce’s rate of 8.7% minority involvement is dismal [2]. Certain anesthesia professions carry this inequity more than others. For instance, of the 4,851 nurse anesthetists who completed the Academic Association of Nurse Anesthetists’ annual demographic survey, less than 3% identified themselves as an underrepresented ethnic minority [6]. While disparity has diminished since 1990, in terms of graduates from baccalaureate nursing programs and medical schools, growth is slow [2]. 

The most integral reason for racial inequity in the anesthesia professions is education [7]. The education pipeline in the United States overwhelmingly fails underrepresented minorities, with an estimated one in ten African American students and one in five Latinx students dropping out before completing high school [7]. Scholars suggest that the crucial time to address the problem begins during primary school [7]. Interventions at the high school and college level are also notably beneficial but must be coordinated with broader efforts [7]. 

The importance of sustaining diversity in the various anesthesia professions will not only serve the aspiration of a more equal society but will likely lead to better patient outcomes in the long-term. For one, exposure to diversity in the field enhances physicians’ cultural competence, such that they become more capable of treating patients from diverse backgrounds [8]. Additionally, because non-white medical professions are more likely to practice in underserved areas, achieving a more diverse workforce will diminish the regional disparities that lead to inadequate care for certain communities [8].  

References 

[1] “Quick Facts,” Census Bureau, Washington, DC, USA, July 2019. [Online]. Available: https://www.census.gov/quickfacts/fact/table/US/PST045219. 

[2] E. B. Malinzak, A. Thompson, and T. Straker, “Examining Diversity in Anesthesiology Grand Rounds,” ASA Monitor, vol. 84, p. 38-40, May 2020. [Online]. Available: https://pubs.asahq.org/monitor/article/84/5/38/108534/Examining-Diversity-in-Anesthesiology-Grand-Rounds. 

[3] P. Toledo et al., “Diversity in the American Society of Anesthesiologists Leadership,” Anesthesia and Analgesia, vol. 124, no. 5, p. 1611-1616, November 2015. [Online]. Available: https://doi.org/10.1213/ANE.0000000000001837. 

[4] C. A. Wong and M. C. Stock, “The Status of Women in Academic Anesthesiology: A Progress Report,” Anesthesia and Analgesia, vol. 107, no. 1, p. 178-184, July 2008. [Online]. Available: https://doi.org/10.1213/ane.0b013e318172fb5f. 

[5] M. Baird et al., “Regional and Gender Differences and Trends in the Anesthesiologist Workforce,” Anesthesiology, vol. 123, p. 997-1012, November 2015. [Online]. Available: https://doi.org/10.1097/ALN.0000000000000834. 

[6] T. M. Durbin, “You’ve Got to be Two, Three Times Better Than Anybody Else: Experiences of Black Nurse Anesthetists in Nurse Anesthesia Education,” University of Tennessee, Knoxville, PhD diss., p. 1-127, May 2020. [Online]. Available: https://trace.tennessee.edu/utk_graddiss/5817. 

[7] K. Grumbach and R. Mendoza, “Disparities In Human Resources: Addressing The Lack of Diversity In The Health Professions,” Health Affairs, vol. 27, no. 2, p. 413-422, March/April 2008. [Online]. Available: https://doi.org/10.1377/hlthaff.27.2.413. 

[8] J. J. Cohen, B. A. Gabriel, and C. Terrell, “The Case for Diversity In The Health Care Workforce,” Health Affairs, vol. 21, no. 5, p. 90-102, September/October 2002. [Online]. Available: https://doi.org/10.1377/hlthaff.21.5.90.  

Magnesium sulfate is a widely used mineral salt supplement in the treatment of a spectrum of conditions. Absorbed in the gastrointestinal tract from our diets and the fourth most abundant cation in the human body, magnesium itself helps maintain ion balance across the cellular membrane, while also acting as a cofactor in multiple biochemical pathways (1) and serving a vital function in neurochemical transmission and muscular contractions. Magnesium sulfate as a treatment currently holds many Food and Drug Administration (FDA) approvals, while also serving numerous off-label uses for a variety of clinical situations, such as after surgery. FDA-improved indications include constipation, hypomagnesemia, and the prevention of seizures in eclampsia/preeclampsia, while non-FDA-approved indications span acute asthma exacerbations, torsades de pointes during advanced cardiac life support (ACLS), and as a tocolytic to prevent preterm labor. To this end, magnesium sulfate administration can be oral, intramuscular, intraosseous, or intravenous. Every 1 gram of magnesium sulfate contains 98.6 mg of elemental magnesium, which can be combined with dextrose 5% or water to form administration-ready intravenous solutions. This said, magnesium-related adverse effects,  such as nausea or vomiting, headache, lethargy, flushing, hypotension, and respiratory depression, may occur at higher blood concentrations of magnesium (2). 

Clinically, transurethral bladder surgery is the gold standard operational intervention to resect a bladder tumor (3). Patients require large-diameter urinary catheters postoperatively (4), frequently resulting in discomfort as a consequence of involuntary muscle contraction. Particularly, catheter-related bladder discomfort above a moderate grade, which is frequently intolerable and requires treatment, is reported among 38-57% of patients with urinary bladder catheters in situ in the post-anesthesia care unit (PACU) (5). Various agents such as ketamine, tramadol, butylscopolamine, and lidocaine have been studied for the prevention of catheter-related bladder discomfort (6,7). In this context, magnesium sulfate too has recently been shown to effectively minimize catheter-related bladder discomfort after transurethral bladder surgery, in particular by relaxing smooth muscle (8). 

Indeed, a landmark 2020 randomized, double-blind, placebo-controlled study from Korea assessing 120 patients recovering from transurethral resection of bladder found that magnesium sulfate substantially reduced discomfort, shrinking the number of patients who required treatment to two. Specifically, magnesium sulfate successfully reduced the incidence of catheter-related bladder discomfort at 0, 1, and 2 hours postoperatively. It also significantly boosted postoperative patient satisfaction, as assessed on a seven-point Likert scale (8). In this study, a 50 mg/kg loading dose of intravenous magnesium sulfate was administered for 15 min, followed by an intravenous infusion of 15 mg/kg/h during the intraoperative period.  

Since only one large study was conducted, it will be necessary to replicate these results across different settings and among different patient cohorts. In addition, further studies are warranted to evaluate the optimal magnesium dose required for the prevention of catheter-related bladder discomfort among patients who required a large-diameter urinary catheter. Further studies are also warranted to confirm the optimal timing required.  

In conclusion, in addition to its wide-ranging applicability in a number of other clinical contexts, magnesium sulfate is emerging as a very promising method of reducing catheter-related bladder discomfort after transurethral bladder surgery. 

References 

1.  Hicks MA, Tyagi A. Magnesium Sulfate. StatPearls; 2020 May 8. PMID: 32119440

2.  Costello R, Wallace TC, Rosanoff A. Magnesium. Vol. 7, Advances in Nutrition. American Society for Nutrition; 2016. p. 199–201.  

3.  Choi WJ, Baek S, Joo EY, Yoon SH, Kim E, Hong B, et al. Comparison of the effect of spinal anesthesia and general anesthesia on 5-year tumor recurrence rates after transurethral resection of bladder tumors. Oncotarget. 2017;8(50):87667–74.  

4.  Hu B, Li C, Pan M, Zhong M, Cao Y, Zhang N, et al. Strategies for the prevention of catheter-related bladder discomfort: A PRISMA-compliant systematic review and meta-analysis of randomized controlled trials. Vol. 95, Medicine (United States). Lippincott Williams and Wilkins; 2016.  

5.  Xiaoqiang L, Xuerong Z, Juan L, Mathew BS, Xiaorong Y, Qin W, et al. Efficacy of pudendal nerve block for alleviation of catheter-related bladder discomfort in male patients undergoing lower urinary tract surgeries: A randomized, controlled, double-blind trial. Med (United States). 2017 Dec 1;96(49). doi: 10.1097/MD.0000000000004859.

6.  Kim DH, Park JY, Yu J, Lee SA, Park S, Hwang JH, et al. Intravenous Lidocaine for the Prevention of Postoperative Catheter-Related Bladder Discomfort in Male Patients Undergoing Transurethral Resection of Bladder Tumors: A Randomized, Double-Blind, Controlled Trial. Anesth Analg. 2020;131(1):220–7.  

7.  Nam K, Seo JH, Ryu JH, Oh AY, Lee T, Park HP, et al. Randomized, clinical trial on the preventive effects of butylscopolamine on early postoperative catheter-related bladder discomfort. Surg (United States). 2015 Feb 1;157(2):396–401.  

8.  Park JY, Hong JH, Kim DH, Yu J, Hwang JH, Kim YK. Magnesium and bladder discomfort after transurethral resection of bladder tumor: A randomized, double-blind, placebo-controlled study. Anesthesiology. 2020;133(1):64–77.  

Though COVID-19 is known for the respiratory symptoms it elicits in most symptomatic cases, it also causes neurological symptoms in a minority of cases. These neurological symptoms can range from minor and short-lived to serious, and they have emerged in infected individuals at varying levels with regard to age and comorbidities. Researchers have sought both to treat respiratory symptoms as a means of reducing neurological ones and to determine whether infection of the nervous system causes symptoms in COVID-19 patients. 

In a survey of hospitalized COVID-19 patients in New York, one in seven reported neurological symptoms [1]. Another study of patients in Wuhan, China, however, concluded that 36.4% experienced them [2]. Neurological symptoms usually developed within two days of other symptoms appearing [3]. At their most innocuous, patients experienced headache, dizziness, and confusion, but certain patients have experienced strokes and seizures. Furthermore, some have speculated that the loss of olfactory sensation common in COVID-19 patients may have neurological causes [4]. 

Just as older patients tend to have higher COVID-19 death rates, they are also more likely to suffer from serious neurological dysfunction as a result of the virus: one study found the median age of hospitalized patients with neurological symptoms to be 71, a full 7 years older than those without neurological symptoms [3]. Those with comorbidities, including but not limited to prior neurological problems, were also more likely to experience them during COVID-19 infection. For instance, 19% of those with neurological symptoms had a history of ischemic stroke, compared to 7% without [3]. However though race has been correlated with COVID-19 deaths in the U.S., it does not appear to be correlated with rates of neurological symptoms. 

In many cases, respiratory infection is likely the cause of these symptoms. Low blood oxygen levels, for instance, can cause the feelings of confusion common in COVID-19 patients [1]. Indeed, symptoms such as headache and dizziness are common across viral infections and may reveal little about COVID-19 specifically [4]. Thus, researchers have suggested that treating respiratory symptoms and raising blood oxygen levels is the most reliable way to reduce the threat of neurological damage [3]. 

However, more research is needed on the topic of whether COVID-19 can directly infect the nervous system. Pezzini and Padovani describe three potential routes by which the virus may create neurological effects: as an effect of pulmonary disease and other systems’ breakdown, as a direct effect of central nervous system infection, or as a result of post-infection complications [5]. There have been scattered reports of encephalitis, including in a previously healthy 11-year-old, but it remains unclear whether nervous system infection is responsible for these cases [4,6]. Meanwhile, as Butowt et al. note, some have theorized that the loss of smell experienced by many COVID-19 patients may come about as a result of the virus destroying olfactory neurons, or else due to the virus infecting olfactory centers in the brain, possibly via the nose. However, they argue that these symptoms are more likely to be caused by the virus destroying sustentacular cells in the olfactory epithelium [7]. 

Though most COVID-19 cases do not involve neurological symptoms, a significant number do, usually in patients with already-serious cases. These symptoms are generally linked to respiratory infection, though some researchers posit that nervous system infection may play a role in effects such as anosmia.  

References 

[1] “COVID-19 Frequently Causes Neurological Injuries.” NYU Langone News, NYU Langone Health, 2020, nyulangone.org/news/covid-19-frequently-causes-neurological-injuries. 

[2] Mao, Ling, et al. “Neurological Manifestations of Hospitalized Patients with COVID-19 in Wuhan, China: a Retrospective Case Series Study.” Medrxiv, 25 Feb. 2020, doi:10.1101/2020.02.22.20026500. 

[3] Frontera, Jennifer A., et al. “A Prospective Study of Neurologic Disorders in Hospitalized COVID-19 Patients in New York City.” Neurology, 5 Oct. 2020, doi:10.1212/wnl.0000000000010979.  

[4] Chen, Xiangliang, et al. “A Systematic Review of Neurological Symptoms and Complications of COVID-19.” Journal of Neurology, 2020, doi:10.1007/s00415-020-10067-3. 

[5] Pezzini, Alessandro, and Alessandro Padovani. “Lifting the Mask on Neurological Manifestations of COVID-19.” Nature Reviews Neurology, vol. 16, no. 11, 24 Aug. 2020, pp. 636–644., doi:10.1038/s41582-020-0398-3. 

[6] Mcabee, Gary N., et al. “Encephalitis Associated with COVID-19 Infection in an 11-Year-Old Child.” Pediatric Neurology, vol. 109, 24 Apr. 2020, p. 94., doi:10.1016/j.pediatrneurol.2020.04.013.  

[7] Butowt, Rafal, and Christopher S von Bartheld. “Anosmia in COVID-19: Underlying Mechanisms and Assessment of an Olfactory Route to Brain Infection.” The Neuroscientist. 11 Sep. 2020, doi:10.1177/1073858420956905. 

Malignant hyperthermia (MH) is an uncommon but life-threatening pharmacogenetic disorder that can occur in response to general anesthesia. MH is triggered by certain volatile anesthetics, either alone or co-administered with the depolarizing muscle relaxant succinylcholine. Uncontrolled release of calcium ions in muscle cells leads to extensive muscle fiber contraction, resulting in excessive heat and metabolic acidosis. MH thus results in the classic signs of hyperthermia, reactive muscle rigidity, high fever, and fast heart rate, alongside muscle breakdown and high blood potassium levels (1), which, left untreated, are likely to be fatal. Globally, its incidence during general anesthesia ranges from 1:5,000 to 1:100,000, representing a significant burden on healthcare systems (4). 

Effective malignant hyperthermia management is built upon the pre-emptive assessment of individual susceptibility and preventive care. To this end, the “gold standard” for the diagnosis of MH currently consists of an in vitro muscle contracture test (5,6), though DNA analyses of MH-associated loci now also offer a minimally invasive alternative to screen for any disease-predisposing variants (2). The incidence of genetic predispositions is estimated at 1 in 3,000 people (3). Thereafter, once a patient is placed under anesthesia, careful monitoring is paramount to swiftly identify any emerging signs of MH. To this end, core temperature should be assessed in all patients undergoing general anesthesia for periods exceeding 60+ mins (7). 

Research suggests that a case of MH is most effectively treated via a sequence of targeted interventions: 1) immediately discontinuing the triggering agent – volatile anesthetic and/or succinylcholine, 2) hyperventilation with 100% oxygen at maximum fresh gas flow to stabilize patient hemodynamics, and 3) administration of the muscle relaxant dantrolene (2-2.5 mg/kg) pro re nata – until the patient is clinically stable. Activated charcoal may also be inserted at this point into the breathing circuit to absorb and minimize the concentration of lingering anesthetic (8). As soon as it is safe to do so, surgery should be terminated (9).  

If dantrolene is not available or if the patient’s hyperthermia is severe enough to warrant additional measures, the patient should be cooled with the goal of reaching a core temperature of no more than 38.5°C. Such methods include the administration of cold (4^oC) intravenous saline, skin cooling via cold packs, peritoneal exchange, forced ambient air cooling, circulating cool water blankets, and ice water immersion. In the most extreme circumstances, a cardio-pulmonary bypass or extracorporeal membrane oxygenation may also be implemented as appropriate (11).  

Furthermore, certain physiological perturbances can receive targeted treatments. For example, hyperkalemia can be directly treated with bicarbonate and/or intravenous glucose and insulin. While arrhythmias secondary to hyperkalemia are usually naturally reversible, these may be treated as necessary with intravenous calcium chloride; calcium antagonists are contraindicated if dantrolene has been administered. Forced diuresis using fluids and/or furosemide may be effective in preventing acute renal failure. Following these initial treatment steps, given that 25 % of patients experience symptom recurrence, patients should be closely monitored for up to 72 h (10). 

As an additional resource, a hotline has been established to provide emergency assistance during the management of MH. Guidelines may also be accessed in real-time via the official website curated by the Malignant Hyperthermia Association of the United States (MHAUS) (12), alongside a detailed follow-up protocol to abide by until all signs have subsided (10).  

A number of complementary treatments have been developed to manage this condition (8). Indeed, increased understanding of the condition’s pathophysiology has led to a strong decrease in MH-associated mortality rates from 80 % 30 years ago to less than 5 % (1). 

References  

1. Rosenberg H, Pollock N, Schiemann A, Bulger T, Stowell K. Malignant hyperthermia: a review. Orphanet J Rare Dis. 2015 Aug 4;10(1):1–19. DOI: 10.1186/s13023-015-0310-1. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4524368/ 

2. Allen GC. Malignant hyperthermia susceptibility. Vol. 12, Anesthesiology Clinics of North America. 1994. p. 513–35. Retrieved from: https://www.ncbi.nlm.nih.gov/books/NBK1146/ 

3. Kim DC. Malignant hyperthermia. Vol. 63, Korean Journal of Anesthesiology. Korean Society of Anesthesiologists; 2012. p. 391–401. DOI: 10.4097/kjae.2012.63.5.391. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3506847/ 

4. Rosenberg H, Davis M, James D, Pollock N, Stowell K. Malignant hyperthermia. Vol. 2, Orphanet Journal of Rare Diseases. Orphanet J Rare Dis; 2007. DOI: 10.1186/1750-1172-2-21. Retrieved from: https://pubmed.ncbi.nlm.nih.gov/17456235/ 

5. A protocol for the investigation of malignant hyperpyrexia (mh) susceptibility. Br J Anaesth. 1984 Nov;56(11):1267–71. DOI: 10.1093/bja/56.11.1267. Retrieved from: https://pubmed.ncbi.nlm.nih.gov/6487446/ 

6. Larach MG, Landis JR, Bunn JS, Diaz M. Prediction of malignant hyperthermia susceptibility in low-risk subjects: An epidemiologic investigation of caffeine halothane contracture responses. Anesthesiology. 1992;76(1):16–27. DOI: 10.1097/00000542-199201000-00003. Retrieved from: https://pubmed.ncbi.nlm.nih.gov/1729931/ 

7. Sessler DI. Temperature monitoring and perioperative thermoregulation. Anesthesiology. 2008. DOI: 10.1097/ALN.0b013e31817f6d76. Retrieved from: https://pubmed.ncbi.nlm.nih.gov/18648241/ 

8. Riazi S, Kraeva N, Hopkins PM. Updated guide for the management of malignant hyperthermia. Can J Anesth. 2018 Jun 1;65(6):709–21. Retrieved from: https://link.springer.com/article/10.1007/s12630-018-1108-0 

9. Schneiderbanger D, Johannsen S, Roewer N, Schuster F. Management of malignant hyperthermia: Diagnosis and treatment. Vol. 10, Therapeutics and Clinical Risk Management. Dove Medical Press Ltd.; 2014. p. 355–62. DOI: 10.2147/TCRM.S47632. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4027921/ 

10. Burkman JM, Posner KL, Domino KB. Analysis of the clinical variables associated with recrudescence after malignant hyperthermia reactions. Anesthesiology. 2007. DOI: 10.1097/01.anes.0000265148.86566.68. Retrieved from: https://pubmed.ncbi.nlm.nih.gov/17457120/ 

11. Wasserman DD, Healy M. Cooling Techniques For Hyperthermia. StatPearls. 2018. Retrieved from: https://www.ncbi.nlm.nih.gov/books/NBK459311/ 

12. Home – MHAUS. Available from: https://www.mhaus.org/