Breathing and Digestion: A Tale of Two Systems

Dr. Godinez first ordered a chest X-ray (CXR), one of the most common respiratory diagnostic procedures. "A chest X-ray will give us a two-dimensional image of your chest cavity, including your lungs, heart, and surrounding structures," she explained to Mason. "It can help us identify any obvious abnormalities like pneumonia, fluid accumulation, or structural issues."

Within an hour, Mason was lying on the X-ray table as the radiologic technologist positioned him.

"Take a deep breath and hold it," instructed the technologist as she captured the image. The process was quick and painless, taking only minutes to complete.

The chest X-ray revealed some haziness in the lower lobes of both lungs, but no obvious consolidation or masses. There was also evidence of flattened diaphragms, a potential sign of chronic obstructive pulmonary disease (COPD).

"Based on your X-ray results and symptoms, I'd like to perform a pulmonary function test (PFT)," Dr. Godinez told Mason when reviewing the results. "This will give us more detailed information about how well your lungs are working."

Mason was escorted to the pulmonary laboratory where a respiratory therapist, Sayed Wilson, greeted him.

"A PFT measures several aspects of lung function," Sayed explained. "We'll be looking at your lung volumes, airflow rates, and how efficiently your lungs exchange oxygen and carbon dioxide."

Mason sat in front of a machine called a spirometer. Sayed instructed him to place his lips tightly around the mouthpiece.

"First, I want you to breathe normally," Sayed directed. "Then, when I tell you, take the deepest breath you can and blow out as hard and fast as possible until you can't exhale anymore."

Mason followed the instructions as Sayed encouraged him through several maneuvers. The spirometer measured his forced vital capacity (FVC), the total amount of air he could exhale after a maximum inhalation, and his forced expiratory volume in one second (FEV1), the amount of air he could forcefully exhale in the first second.

The results showed that Mason's FEV1 was significantly reduced at 65% of predicted value, and his FEV1/FVC ratio was below normal at 68%, indicating airflow obstruction consistent with obstructive lung disease.

"These results suggest moderate obstructive lung disease," Dr. Godinez explained when reviewing the PFT results. "Given your history as a former smoker and these findings, you likely have COPD, specifically chronic bronchitis."

To confirm oxygen (O2) exchange efficiency, Dr. Godinez ordered an arterial blood gas (ABG) test. A technician drew blood from Mason's radial artery in his wrist.

"The ABG will measure the levels of oxygen and carbon dioxide in your blood," Dr. Godinez explained. "This helps us understand how well your lungs are exchanging gases."

The results showed mild hypoxemia (low oxygen) with a PaO2 (partial pressure of arterial oxygen) of 78 mmHg (normal is 80-100 mmHg) and normal carbon dioxide levels with a PaCO2 (partial pressure of arterial carbon dioxide) of 40 mmHg (normal is 35-45 mmHg).

Dr. Godinez continued “Think of partial pressure like this: when you have a mixture of gases (like the air we breathe), each gas pushes against the walls of its container with its own individual force. Partial pressure is how hard each specific gas is pushing. In your blood, we measure how hard oxygen (O₂) and carbon dioxide (CO₂) are pushing against the walls of your blood vessels. The higher the partial pressure, the more of that gas is dissolved in your blood. We measure this pressure in millimeters of mercury (mmHg), just like a blood pressure cuff.”

While discussing the respiratory findings, Mason mentioned again his increasing digestive discomfort. "The breathing problems are bad enough, but lately, I can barely eat without feeling like my food is coming back up. Sometimes I even taste acid in my mouth, especially when I lie down."

Dr. Godinez nodded thoughtfully. "Those symptoms suggest gastroesophageal reflux disease, or GERD. This could actually be contributing to your respiratory symptoms as well. When stomach acid refluxes up into the esophagus, it can sometimes be aspirated into the lungs, worsening respiratory conditions."

She decided to consult with Dr. Tao, a gastroenterologist, for a more comprehensive evaluation of Mason's digestive issues.

Dr. Tao met with Mason later that day. "Let's talk about your digestive system and what might be happening," she began. "Food travels through your digestive tract, starting at your mouth, where digestion begins with enzymes in your saliva breaking down starches."

Using an anatomical model on her desk, Dr. Tao traced the path of food. "After swallowing, food passes through your esophagus to your stomach. The esophagus is a muscular tube about 10 inches long that connects your throat to your stomach."

She pointed to the stomach on the model. "Your stomach is where food is mixed with gastric juices containing hydrochloric acid and enzymes, beginning protein digestion. From there, partially digested food moves into the small intestine."

Dr. Tao explained that the small intestine consists of three sections: the duodenum, jejunum, and ileum. "Most nutrient absorption happens in the small intestine, which is about 20 feet long. The duodenum receives digestive enzymes from the pancreas and bile from the liver and gallbladder to help break down fats, proteins, and carbohydrates."

She continued tracing the digestive path. "After the small intestine, what remains passes into the large intestine or colon, which absorbs water and electrolytes. Finally, waste is eliminated through the rectum and anus."

Pointing back to the junction between the esophagus and stomach, Dr. Tao explained, "There's a sphincter here called the lower esophageal sphincter (LES). When functioning properly, it prevents stomach contents from flowing backward into the esophagus. In GERD, this sphincter doesn't close completely, allowing acid to reflux upward, causing the burning sensation you're experiencing."

To confirm the diagnosis of GERD and rule out other digestive issues, Dr. Tao recommended an upper endoscopy.

"An upper endoscopy allows us to visualize your esophagus, stomach, and the first part of your small intestine using a flexible tube with a camera," she explained. "We can see if there's inflammation, ulcers, or other abnormalities that might explain your symptoms."

The procedure was scheduled for the following day. Mason arrived after fasting overnight and was given conscious sedation to make him comfortable during the procedure. Dr. Tao carefully inserted the endoscope through Mason's mouth and down his esophagus.

The endoscopy revealed inflammation in the lower esophagus, consistent with GERD. Dr. Tao also noted a small hiatal hernia, where a portion of the stomach was protruding through the diaphragm into the chest cavity.

"The hiatal hernia is likely contributing to your GERD," Dr. Tao explained after the procedure. "It's disrupting the normal function of your lower esophageal sphincter, making it easier for acid to reflux upward."

With diagnoses for both systems established, Dr. Godinez and Dr. Tao met to discuss Mason's treatment plan. They recognized that his respiratory and digestive issues were interconnected.

"The GERD is likely exacerbating his COPD symptoms," Dr. Godinez noted. "Microaspiration of stomach acid can trigger bronchospasm and inflammation in the airways."

"And his coughing from COPD increases abdominal pressure, which can worsen the reflux," added Dr. Tao. "It's a vicious cycle."

They developed a comprehensive treatment plan addressing both conditions.

Respiratory Therapeutic Interventions

For Mason's COPD, Dr. Godinez prescribed several therapeutic interventions:

1. Bronchodilators: "I'm prescribing two types of inhalers," she explained to Mason. "A short-acting beta-agonist (SABA) called albuterol (Ventolin HFA) for quick relief when you're feeling short of breath, and a long-acting muscarinic antagonist (LAMA) called tiotropium (Spiriva) that you'll use once daily to keep your airways open."
2. Inhaled Corticosteroids: "I'm also adding an inhaled corticosteroid (ICS) called fluticasone (Flovent) to reduce inflammation in your airways," Dr. Godinez continued. "This will help decrease mucus production and swelling."
3. Oxygen Therapy: Given Mason's borderline oxygen levels, Dr. Godinez recommended oxygen assessment during exercise and sleep. "We'll perform a six-minute walk test while monitoring your oxygen levels to see if you desaturate with activity," she explained. "Depending on the results, you might benefit from supplemental oxygen during exertion or sleep."
4. Pulmonary Rehabilitation: "I'm referring you to our pulmonary rehabilitation program," Dr. Godinez added. "This includes exercise training, breathing techniques, and education about managing COPD. It's proven to improve quality of life and reduce hospitalizations for COPD patients."

The respiratory therapist demonstrated proper inhaler technique to Mason. "Remember to exhale completely before using your inhaler," Sayed instructed. "Then inhale slowly and deeply as you activate the inhaler, and hold your breath for about 10 seconds to allow the medication to reach deep into your lungs."

For Mason's GERD and hiatal hernia, Dr. Tao recommended:

1. Proton Pump Inhibitors (PPIs): "I'm prescribing omeprazole (Prilosec), which reduces acid production in your stomach," Dr. Tao explained. "Take it 30 minutes before breakfast for maximum effectiveness."
2. Lifestyle Modifications: "Elevate the head of your bed by 6-8 inches using blocks or a wedge pillow," she advised. "Avoid eating within three hours of bedtime, and limit foods that trigger reflux like spicy foods, citrus, tomatoes, chocolate, coffee, and alcohol."
3. Weight Management: "Losing even 5-10% of your body weight can significantly improve GERD symptoms by reducing pressure on your stomach," Dr. Tao noted, as Mason was about 25 pounds overweight.
4. Smaller, More Frequent Meals: "Instead of three large meals, try eating five smaller meals throughout the day to reduce pressure on your LES," she suggested.

Before discharging Mason, the healthcare team created a comprehensive follow-up plan:

1. Return in two weeks to assess response to medications.
2. Complete pulmonary function tests again in three months.
3. Begin pulmonary rehabilitation within one week.
4. Follow up with the gastroenterologist in one month.
5. Keep a symptom diary tracking both respiratory and digestive symptoms.

"Remember, these conditions are chronic but manageable," Dr. Godinez reassured Mason. "With proper treatment and lifestyle changes, most patients see significant improvement in their symptoms and quality of life."

Mason returned for his six-month follow-up appointment with both specialists. His transformation was remarkable.

"I can breathe so much better now," he reported. "I've been using my inhalers as prescribed and completed the pulmonary rehabilitation program. I can even help in the kitchen at my restaurant again without getting winded."

His pulmonary function tests showed improvement, with his FEV1 increasing to 75% of predicted value. His oxygen saturation remained stable at 96% on room air.

The GERD symptoms had also improved significantly. "I haven't had heartburn in months," Mason shared. "Elevating my bed and changing my eating habits made a huge difference. I've lost 18 pounds, and I think that's helped too."

Dr. Godinez smiled. "This case illustrates how interconnected our body systems are. By addressing both your respiratory and digestive issues comprehensively, we've been able to break the cycle where each condition was worsening the other."

Mason nodded in agreement. "I never realized how much my stomach problems were affecting my breathing, or vice versa. I'm just grateful to have both under control now."

As Mason prepared to leave, Dr. Godinez handed him a summary of his care plan. "Continue following this regimen, and we'll see you again in six months. Remember, consistency with your medications and lifestyle changes is key to managing these chronic conditions."

Mason tucked the care plan into his pocket, taking a deep, satisfying breath—something that had seemed impossible just months ago. The journey through diagnosis and treatment had given him not just relief from symptoms, but a deeper understanding of how the respiratory and digestive systems work together to maintain health.