Pulmonary Complications and Preoperative Pulmonary Evaluation

More pulmonary than cardiovascular complications

In general, any surgery imposes a risk to every system in our body. Most of the complications of surgery are related to cardiovascular events as well as infections. However Pulmonary complications after surgery are also frequent and probably more than the cardiovascular.

Which after-surgery complications in the lungs?

Typical pulmonary complications are local infections like pneumonia, disordered gas exchange with respiratory failure, bronchospasm (wit symptoms of asthma), marginal collapse of portions of the lungs (also called atelectasis), and/or exacerbations of previously existing pulmonary conditions (e.g. exacerbation of COPD).

What predisposes to pulmonary complications?

The nature of the pulmonary complications can be related to the surgical procedure itself or to the patient. The surgical procedure may be described according to site, duration, and anesthesia from which it may be expected that procedures close to the thorax, prolonged interventions, and general anesthesia are associated with subsequent pulmonary complications.

However, patients may also predispose to some risk of complications in the pulmonary structure and functions. Patients with chronic lung diseases tend to have more complications, especially patients with COPD. Age >60 years old, smoking condition, deficient health condition, and heart failure are potential elements of risk for pulmonary complications.

How a physician gather facts over issues to solve

These facts make it necessary to assess patients in plan of surgery for potential lung localized detrimental events. The interview of a patient under surgery program must include questions related to previous lung diseases, isolated respiratory symptoms, and smoking status. The physical examination must also be directed to find anomalies of the pulmonary area as well as trachea at the neck.

The laboratory studies of patients with positive findings in history of physical exam will mandate assessing with one or several of: pulmonary function tests (spirometry), arterial blood gas analysis, chest X-rays, and serum albumin.

Recommendations to the patient

After consideration of risk, patients would be able to receive instructions like: smoking cessation, COPD optimization of therapy, and some recommendations after surgery: lung expansion maneuvers, appropriate analgesia and prophylaxis of deep venous thrombosis. For some patients it may be required other methods of lung ventilation and controlled use of nasogastric tubes (indicating them just when really necessary and not as routine).

In summary

Patients are susceptible of lung complications when they go through a surgical procedure and an appropriate approach may minimize the occurrence of those complications.

Lungs, Kidneys, Oxygen: an orchestrated response

Receiving all circulating blood

Lungs and Kidneys work in an orchestrated manner to maintain an appropriate level of oxygen in blood. Both organs receive all blood flow at one point. Lungs receive blood to facilitate gas exchange: CO2 released and oxygen caught from air. Kidneys filtrate the blood to clear from many residues of metabolism. Given these circumstances, these organs are perfect to carry on with all the blood during its circulation.

Filtering but controlling what’s being filtered

However, what about if lungs fail to catch oxygen and this gas is reduced in blood. Which organ should control the signal? If this task is deferred to the brain the consequences may be deleterious for the entire body. Then, the best option is to give this duty to kidneys.

The kidney’s erithropoyetin

When kidneys sense that the blood being filtered is lacking oxygen, they cooperate recommending the creation of more red cells with enough Hemoglobin (Hb) to catch up oxygen from lungs. The renal cooperation is provided with an hormone called erithropoyetin which works at the bone marrow to induce the formation of red blood cells (RBC) that may be able to take oxygen and bring it to the tissues.

Erithocytosis: increased red blood cells

This situation may take some time (when kidneys consider that the lack of oxygen seems to be serious). The resultant condition is an increased level of RBC with high levels of Hb. This effect is called erithrocytosis, erithremia, polyglobulia, secondary polycytemia, and so forth. Blood turns into thick and slow during its circulation leading to some dizziness and headaches.

Cardiovascular effect of erithrocytosis

With this type of blood, the heart needs to work harder: how to push this heavy luggage? The condition may generate a bigger heart in terms of walls with less space to fill.

Lung diseases as responsible of erithrocytosis

Many lung illnesses are signaled by the presence of secondary erithrocytosis due to difficulties in allowing the access of oxygen to the blood. Advanced stages of COPD are presented with high levels of Hb and RBC and this indicates distant complications from the lungs. The Chronic Bronchitis phenotype (constant cough and sputum production) is classically accompanied with erithrocytosis and increased Hb.

Not a healthy feature

The key fact is that secondary erithrocytosis with high Hb is not a healthy feature when they are seen in an adequate context. COPD and its eventual lung decrease in oxygen catch leads to kidney to send signals that create a huge confusion in the body with a consequence as the one described.

Final point

It’s good to assess oxygen levels and blood samples to evaluate further the lung and kidney cooperation in many pulmonary diseases. And this is just one of several joined efforts of lungs and kidneys preserving our corporal functions.