Acute coronary syndrome (ACS) is a term that encompasses acute myocardial infarction (AMI): ST-elevation myocardial infarction (STEMI), non-ST-elevation myocardial infarction (NSTEMI), and unstable angina. Ischemic heart disease (IHD), a term used interchangeably with ACS, is the greatest single cause of mortality, resulting in roughly 7 million deaths annually worldwide (Vedanthan, Seligman, & Fuster, 2014). In the United States, someone suffers from a myocardial infarction (MI) every 40 seconds (AHA, 2017).
During my ACLS training this summer, the instructor stressed the importance of rapid EMS dispatch, transport, and pre-arrival notification to a reperfusion-capable facility, as this is a critical step in the STEMI Chain of Survival.
As per the American Heart Association (AHA, 2015) guidelines, early detection and prompt reperfusion therapy using percutaneous coronary intervention (PCI), thrombolytic therapy, or coronary artery bypass graft (CABG) surgery are the standards of care. The use of supplemental oxygen is suggested only in patients with dyspnea, hypoxia (O2 < 90%), or obvious signs of heart failure. Because its usefulness has not been established in normoxic patients with suspected or confirmed ACS, providers must use their discretion as to whether or not to administer oxygen (Abuzaid et al.
, 2018). The ideal time frame for the administration of fibrinolytic therapy is within 30 minutes of arrival and PCI within 90 minutes of arrival. As per AHA (2015), half of the patients who die of ACS do so before they even reach the hospital, and not all patients who make it to the hospital are eligible to receive fibrinolytic therapy, leaving PCI as the most viable option, again, keeping in mind that not all hospitals are equipped for PCI.
Prior research on hyperbaric oxygen treatment (HBOT) as an adjunct to reperfusion therapy is inconclusive, and further research must be conducted to deduce whether adjunctive hyperbaric oxygen therapy can help reduce the amount of ischemic or infarcted myocardium (Bennet, Lehm, & Jepson, 2015).
It is no secret that IHD is among the leading cause of mortality and loss of disability-adjusted-life-years (DALYs), not only in the United States but also worldwide (Vedanthan, Seligman, & Fuster, 2014). Additionally, this issue carries a hefty global economic burden, accounting for a projected $47 trillion in economic losses to non-communicable diseases over the next 20 years. ‘Americans suffer 1.5 million heart attacks and strokes each year, a burden that contributes to most of the more than $320 billion in annual healthcare costs and lost productivity caused by cardiovascular disease,’ said Barbara Bowman, Ph.D., director of CDC’s Division for Heart Disease and Stroke Prevention. I believe that IHD is a multifactorial issue that requires a multifactorial approach, which should include preventative measures. However, the staggering statistics of those already affected by the disease process provide a great reason to work toward improving the reperfusion protocol by adding adjunctive HBOT. Hopefully, we can assist in lowering the mortality rate and disabilities associated with IHD, not only in the United States but also worldwide.
The mean body mass index (BMI) has been increasing in every region of the world, giving rise to several IHD risk factors. IHD impacts low-middle income countries (LMICs) and high-income countries (HICs) alike. IHD is a major cause of mortality among the HICs, while approximately two-thirds of all IHD DALYs and more than half of the deaths occur in LMICs (Vedanthan, Seligman, & Fuster, 2014). The World Bank and the World Health Organization predict that depression and coronary heart disease will be the largest causes of global health burden and disability by the year 2020 (Disante, Bires, Cline, & Waterstram-Rich, 2017). These statistics allow us to view the issue of IHD on a much larger scale; this is a worldwide issue that does not discriminate—it affects the rich, the poor, and people of all ethnicities alike. This illustrates the reality that the repercussions of IHD have become a global burden. Exploration of HBOT as a viable adjunct in the treatment of ACS can lead to the adoption of a new protocol worldwide and has the potential to cause a major improvement in survival rates and patient outcomes.
IHD is a pandemic that affects millions of people each year. The objective is to reduce the detrimental effects of heart muscle exposed to anoxia by adjuvant HBOT therapy. Ischemia occurs when all or part of a coronary artery is occluded, causing the heart muscle to be deprived of oxygen, thus leading to its death. As the time of exposure to anoxia increases, so does the damage to the myocardium (CDC, 2017).
While hyperbaric oxygen treatment (HBOT) is widely used for decompression sickness, carbon monoxide poisoning, gas gangrene, post-radiation burns, and treatment of poorly healing wounds, the same concept has not made strides in the treatment of cardiovascular injuries (Kozakiewicz, et al., 2018). According to Nikitopoulou and Papalimperi (2015), HBOT is achieved when the patient is breathing 100% oxygen intermittently, in a closed chamber, while the chamber pressure is > 1atm. HBOT induces high oxygen partial pressure in all tissues; it causes activation of fibroblasts and macrophages, stimulates angiogenesis, and has a bacteriostatic and bacteriocidic effect. HBOT can help preserve ischemic tissues by inhibiting the adhesion of leukocytes to the endothelium of vessels and is likely to have a beneficial effect on reperfusion injury syndromes such as MI and ischemic stroke. (p. 2)
I strongly believe that how HBOT aids in the treatment of the aforementioned conditions can also significantly reduce the amount of cardiac muscle lost due to anoxia.
The standards of reperfusion protocols are constantly evolving, which means that the perfect solution has not been found. Investigating supplemental ways to reduce the myocardial damage caused by ischemia is just as relevant as fibrinolytic and percutaneous measures.
Thus, an inquiry arises: Does hyperbaric oxygen treatment reduce the amount of infarcted myocardium when used as an adjunct to reperfusion therapy in ACS? The findings of such research could potentially decrease the economic burden of healthcare costs associated with ACS, lessen the loss of productivity, and most importantly, reduce ACS-related disabilities and deaths. This means less need for invasive procedures, less downtime from HBOT as opposed to an IABP procedure or CABG, and a reduction in healthcare expenditures on the treatment of IHD.
A quantitative, blind, experimental research design would be ideal for measuring the effects of HBOT on the size of infarcted myocardium in ACS, as it would allow for researchers to introduce, compare, and test the effects of the assigned treatment while avoiding the possibility of developing a bias. Quantitative research is aligned with the positivist paradigm; the positivist approach seeks objectivity and involves the use of orderly disciplined procedures with tight controls over the research situation to seek understanding and relationships among the phenomena being studied (Polit & Beck, 2018). The research would be comprised of randomized controlled trials in persons with suspected or proven AMI without hypoxia (O2 Sat >95%), including both STEMIs and non-STEMIs. Group 1 will receive adjunctive HBOT, and group 2 will be treated with standard MI protocol on room air. Measuring biochemical markers troponin I and CK-MB, 12-48 hours after the initial onset of symptoms, will identify the size of an infarct. This will allow any notable differences present among the two groups, before and after the intervention, to be examined (Cabello, Burls, Emparanza, Bayliss, & Quinn, 2016).
Although great strides have been made in improving the reperfusion protocol, the CDC reports suggest that there is room for improvement. Because the existing studies have yielded information that is not statistically significant, further research must be conducted to investigate the efficacy of pressurized oxygen administration in ACS. In researching whether HBOT can help reduce the ischemic damage to the myocardium, revolutionary changes in healthcare and emergency medicine protocols are possible.