ABG Challenge - January, 2017

20 Jan 2017

A 69-year-old female is brought into the emergency department by the local EMS. Her husband called 911 when she became minimally responsive at home. He reports that she has experienced an increase in shortness of breath for the past several hours, in spite of increasing the liter flow on her oxygen concentrator and using her albuterol inhaler. She has a long history of COPD. Her most recent hospitalization was three months ago.

Physical examination reveals a cachectic female who is borderline obtunded. Her respirations are rapid and shallow; breath sounds are distant.

Arterial blood is drawn for analysis while the patient is receiving oxygen via nasal cannula at 4 Lpm.

pH 6.96 PaCO2 136 mmHg HCO3 29 mEq PaO2 94 mmHg SaO2 89% CO 1.9% Hgb 10.2 g/dL Lactate 1.4 mmol/L

Questions

1. What is your interpretation of these blood gas data?

2. Why is the SaO2 so low?

3. Do you believe this patient is hypoxic?

4. Based on these data, what would you do at this point?


 

Respiratory Update Corner - Jan, 2017

19 Jan 2017

Greetings and welcome to the third edition of my blog. Just a reminder that this blog is meant to be a review of recent studies and data primarily related to respiratory medicine. The blog is also meant to be interactive. I would greatly appreciate your feedback. Please address any comments, questions, or concerns to me at professorbillsblog@yahoo.com. Remember: Health care delivery is fascinating, demanding, dynamic, and ever-changing. No one has all the answers (or even all the questions), so don’t be afraid to jump into the fray, express your opinion, share your experience. Your contributions will only serve to strengthen the profession. In addition, if you would like a copy of the first two blogs, please contact me.

Okay, there’s been a lot of interesting stuff related to respiratory medicine in the medical news over the past few months, certainly more than I can report here, but we’ll see if we can at least mention a few of the most relevant (in my opinion, anyway).

1) A number of reports of studies have demonstrated the superiority of LABA/LAMA over LABA/ICS (LABA = long acting beta agonist; LAMA = long acting muscarinic antagonist; ICS = inhaled corticosteroid) in the treatment of COPD. The most widely reported is the FLAME study. This study looked at the combination of indacterol and glycopyrronium versus the combination of salmeterol and fluticasone. The outcome was the number of exacerbations in a year.

While this is an interesting and well-done study, I can’t help wondering how much of an effect the results will have on prescribing patterns. I have known many people with COPD who are on a LABA/ICS combo plus a LAMA (usually tiotropium). Also, as I have indicated before, clinicians need to consider the cost and availability of these medications as well as the patient’s ability to use them properly.

Another study, the CRYSTAL study looked at improvements in lung function (specifically FEV1) in patients with moderate COPD. They used the same combination of LABA/LAMA and showed positive results. It is probably worth noting, however, that this study was sponsored Novartis.

Interestingly (and perhaps ironically), at the same time the FLAME study was being reported, two other large studies confirmed (based on the data) that triple COPD therapy was superior to monotherapy. These studies were the TRINITY and the TRILOGY. TRINITY compared a combination of LABA, LAMA, and ICS to LAMA alone. TRILOGY compared triple therapy with the combination of ICS and LABA. In both studies, the triple combination resulted in better outcomes. It is worth noting that the drug combos, methodologies, and outcomes were slightly different between studies. I guess now we need a study that compares the triple therapy with LABA/LAMA combo using the same drugs.

2) A small study reported in Medscape showed that scrubs can become contaminated with bacteria. The study looked at 40 ICU nurses and found the transmission of six types of bacteria. Some transmission was from patient to nurse; some was from nurse to patient.

This sort of falls in line with recent discussions involving the potential contamination of clinicians’ clothing, including lab coats. One report estimates that 722,000 healthcare-associated infections occur in US hospital, resulting in about 75,000 deaths each year. While this is certainly a serious problem, apparently the jury is still out on the role clothing plays in infection transmission. On the other hand (no pun intended), no one questions the value of diligent hand hygiene. Please pass along to me (see contact information above) what you are doing in your facility to promote hygiene (i.e. changes in uniform policies).

3) A review of 20 perspective studies and published in BMC Medicine apparently found that a ‘handful of nuts a day may be enough to reduce the risk for death from heart disease and other ills.’ According to the report, researchers found that people who ate the most nuts reduced their risk of coronary heart disease, cardiovascular disease, and cancer. They also found a reduced risk for respiratory disease, diabetes, and infectious disease.

I admit that I didn’t track down the original study so I can’t say how the review was conducted or, perhaps more importantly, which nuts were used. As I read the results, I couldn’t help wondering if peanut butter counts. Also, what about all those poor people with nut allergies?

It will be interesting to see if more studies are done and what the results might be. Also, I wonder if these results will somehow be tied to the very recently reported news that exposing infants to nuts may possibly reduce the risk of developing nut allergies later in life.


 

ABG Challenge - October, 2016

20 Oct 2016

An 83-year-old female is admitted to the ED for shortness of breath and change in affect. She has a history of congestive heart failure and COPD. Currently, she has rapid, shallow respirations and is minimally alert. Breath sounds are very decreased throughout. She has an occasional weak, nonproductive cough.

Blood gas data (drawn while the patient is breathing room air):

pH 7.07
PaCO2 96 mmHg
HCO3 27 mEq
PaO2 54 mmHg
SaO2 68%
Hgb 9.7 g/dL
electrolytes within normal limits

1. What is the interpretation of these data?

2. How do you explain the SaO2 being as low as it is?

3. How would you treat this patient?

Answer to ABG Challenge Two

The data indicates a partially compensated metabolic acidosis with overcorrected hypoxemia. The patient is experiencing an episode of diabetic ketoacidosis and will need to be treated accordingly.


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