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Impact of Masks; High vs Low Blood Oxygen: It’s TTHealthWatch!

TTHealthWatch is a weekly podcast from Texas Tech. In it, Elizabeth Tracey, director of electronic media for Johns Hopkins Medicine, and Rick Lange, MD, president of the Texas Tech University Health Sciences Center in El Paso, look at the top medical stories of the week. A transcript of the podcast is below the summary.

0:41 The impact of masks

1:42 Usage varied across the U.S.

2:41 Targeted control measures

3:05 Oxygen targets in people with acute respiratory failure

4:05 Should we target lower or higher oxygen?

5:05 In COVID does it inform?

5:45 Blood pressure medicines and COVID

6:45 Discontinuing did not improve outcome

7:31 Smoking cessation and USPSTF update

8:31 Need to use medicines

9:31 National survey shows only 1/3 used aids to quit

11:00 End

Transcript:

Elizabeth Tracey: What’s the best oxygen target for people with respiratory failure in the ICU?

Rick Lange: Mask-wearing and COVID transmission in the United States.

Elizabeth: What can we do to help those people who continue to smoke?

Rick: And should you discontinue certain hypertensive medicines if you have COVID infection?

Elizabeth: That’s what we’re talking about this week on TT HealthWatch, your weekly look at the medical headlines from Texas Tech University Health Sciences Center in El Paso. I’m Elizabeth Tracey, a Baltimore-based medical journalist.

Rick: And I’m Rick Lange, president of the Texas Tech University Health Sciences Center in El Paso, where I’m also the dean of the Paul L. Foster School of Medicine.

Elizabeth: Rick, why don’t we turn to The Lancet first? This is something that I keep seeing in the popular press as well as in the scientific and medical literature — can we stop wearing masks if we’ve been vaccinated? Let’s just talk about what in the world are they doing good, really, anyway?

Rick: This particular study addresses the latter issue and that is on a population level we really have very little evidence that masks actually help prevent the transmission of COVID infection. These investigators were attempting to answer that question by doing self-reports of facemask wearing — these are surveys conducted across the United States — and then combining that with estimates of the reproductive number. How often does a person transmit COVID infection once they get it?

They also looked at other measures like the social distancing and the community demographics, again, to answer the question, does wearing a mask help prevent transmission? They collected survey data from over 378,000 individuals in June and July of 2020 in which they reported mask usage. What they found is that mask usage varied across the United States. It was more commonly used on the coast and least commonly used in the central part, heading up to the northern part of the United States.

Every 10% increase in self-reported mask wearing was associated with a four-fold likelihood that the transmission was controlled when there was a 10% increase in mask wearing. Communities that had the most mask wearing were least likely to have COVID transmission in those communities, and that was regardless of whether they social distanced or not.

Now, they also looked at whether state mandates helped. They looked at transmission 2 weeks before and 2 weeks after and they realized that it really didn’t. Great empirical — what they call ecological — evidence that mask wearing does prevent COVID transmission.

Elizabeth: Obviously, it is critically important now that we’re having these more infectious variants make their way around the globe and of course there’s this discussion that now we’re going to have a federal mandate for mask wearing.

Rick: Yeah. There are certain targeted control measures that we have. For example, if you’ve been exposed, we isolate you. Or if you have COVID infection, we quarantine you. This is called a non-targeted control measure. We have everybody do it regardless of whether they have symptoms or not and that’s important because many people either have no symptoms, some have symptoms they don’t even recognize as COVID, and what the mask does is it prevents them from giving it to somebody else. These non-targeted measures are going to be incredibly important even after everybody is vaccinated.

Elizabeth: Let’s turn to the New England Journal of Medicine and I picked this one, obviously, because I thought it had some parallels to the care of people with COVID-19, especially many of whom I have seen in the ICU at Hopkins. This is a look at, gosh, what should our oxygen target really be in people who have respiratory failure who are in the ICU?

Interestingly, this falls into the context of things that everybody thinks a priori, “Wow, this just makes sense. Higher oxygen levels are better, of course, and so that’s what we’re going to target for.” Then, when it’s scrutinized a little bit more closely, we find out that, “Well, okay. Is it or isn’t it?” We were talking before we started recording about glucose levels, for example, and how high glucose levels there was intervention attempted in people who were critically ill and it turned out that that was not a good strategy.

So in this case, it’s a Danish study, of course. They randomly assigned just under 3,000 adult patients admitted to the ICU and were receiving at least 10 liters of oxygen per minute. They said, “Okay. Should we target 60 mm of mercury — that’s the lower oxygenation group — or 90, the higher oxygenation group?” They followed them for a maximum of 90 days.

Their primary outcome was death within 90 days. At that earmark, they had almost 43% in the lower oxygenation group and 42% in the higher oxygenation group who had died. The upshot of the whole thing is that it really didn’t seem to make any difference, even with regard to other things like new episodes of shock, MI, ischemic stroke, or intestinal ischemia between them. I think it’s great that we scrutinize this and I’d like to ask you, based on this study, what would you say about the care of people with COVID who have acute respiratory failure?

Rick: As you noted, there was some concern about what the proper level of oxygen should be and there was actually some concern that the higher level was associated with a higher mortality. The importance of this study is it’s evidence-based.

Elizabeth: I would just note to you that we are seeing, especially in some localities — Los Angeles, for example — that oxygen availability is becoming rate-limiting. If it’s possible to drop it lower and not experience higher rates of complications or mortality, maybe that’s a good strategy.

Rick: Elizabeth, it’s interesting because we had noted the same thing during the peak of our pandemic experience here with COVID as well. There is a lot of things you consider in terms of staffing and hospitalization. You never think that oxygen is going to be a limiting factor. But as you’ve mentioned, it is during this pandemic, so this information is very useful.

Elizabeth: Okay. Let’s turn to your next one. That’s in JAMA.

Rick: Why would blood pressure medicines and COVID have any interaction at all? The COVID virus binds to the angiotensin-converting enzyme receptor on the cells and that’s how it gains entry. These ACE inhibitors are also the targets of blood pressure medicines. We have medicines called ACE inhibitors and their counterparts called angiotensin receptor blockers, or ARBs, that are used to treat high blood pressure.

There was some concern because when you use them you increase the number of these receptors that would predispose people to getting infection or having more severe infection, perhaps when someone comes into the hospital with COVID infection you should stop these medications. To test this particular hypothesis, these investigators looked at 659 people that were hospitalized in Brazil with mild to moderate COVID infection and these people were all on an ACE inhibitor or an ARB when they were admitted to the hospital.

They took half of the individuals off those medications, they continued the other half on, and what they discovered was that discontinuing these medications did not improve outcome and it did not affect cardiovascular death, regular death, or COVID-19 progression.

Elizabeth: And so let’s paint the picture just a little bit larger here. What about sudden discontinuation of these medicines? What are the deleterious aspects of that?

Rick: These are medications meant to control hypertension. In people that have uncontrolled hypertension during their hospitalization, that’s not a safe environment for the patient.

Elizabeth: This is interesting to me because clearly this was an issue that was identified super early in the pandemic that this might be a possibility, based on what we know academically about the receptors, and it’s also interesting that it’s taken until now to really be able to definitively answer the question.

Rick: We’ve had different pieces of the puzzle that have looked at it. This was the first randomized trial that has actually taken people off it.

Elizabeth: Staying in JAMA then, let’s turn to the USPSTF, the United States Preventive Services Task Force, and their recent look at smoking cessation. What do we do about that? Very disconcerting statistic here in 2019, one in five U.S. adults use tobacco. Of that number, 14% were smoking cigarettes and the remainder were using electronic cigarettes, and some people, of course, use both. The other bad news is that pregnant women, 7.2% reported smoking cigarettes while pregnant.

The last time the USPSTF looked at this was in 2015. What they basically did was look at 67 reviews that looked at pharmacotherapy and behavioral interventions as well as nine trials addressing e-cigarettes for smoking cessation and seven using nicotine replacement therapy in pregnancy. They came out and said we need to be using these medicines. We need to take a comprehensive approach. The evidence-based behavioral interventions that they are advocating, I’ll say, include individual and group counseling, telephone counseling, and also web- and text-based interventions.

They say that combining short- and long-acting nicotine replacement therapies is more effective than using just a single form, and finally — and I was happy to note — that they have said no e-cigarette, of course, has been approved by the FDA as a cessation aid. But also, this evidence regarding its ability is inconclusive and that, in light of other studies that just came out this week that we’re looking at, compromise of lung function secondary to e-cigarette use, I’m really happy to say that they’re not advocating for that.

Rick: This is an important update for several reasons. One is it highlights things that we know that are effective in helping people stop smoking, and here’s the rub. They did a national survey of almost 33,000 smokers, and two-thirds of them said they really did want to quit. Half of them had tried, but less than a third of them had actually used evidence-based procedures to do so. Accordingly, only about 7% were successful in quitting and keeping that for a year. We have effective ways of helping people stop smoking. The rub is in making individuals aware of them and applying them in the primary care setting.

Elizabeth: I also applaud the fact that they’ve noted that this is not just an individual clinician mandate, that this is really a group effort here, folks. We’ve got to get everybody engaged, including population-level strategies such as increasing the price of tobacco, instituting and enforcing smoke-free policies and mass media education campaigns, and the access to cessation treatments.

Rick: You hit the nail on the head. It’s a combination of public health and personal health at the same time. As clinicians and healthcare providers, we need to ask everybody whether they’re currently smoking, and if so, be prepared to present them with the information and the follow-up to get the means that we know that are effective.

Elizabeth: On that note, here’s to everybody quitting smoking in 2021. That’s a look at this week’s medical headlines from Texas Tech. I’m Elizabeth Tracey.

Rick: And I’m Rick Lange. Y’all listen up and make healthy choices.

Source: MedicalNewsToday.com