Obstructive Lung Disease, Pulmonary Hypertension & Bronchoscopy

Connect the Ventilator to the Circulation

The outline includes COPD exacerbation, asthma, pulmonary arterial hypertension, pulmonary physiology, and bronchoscopy. These subjects test whether the clinician recognizes that an airway pressure or blood gas is a physiologic clue rather than an isolated target. Airflow obstruction lengthens the time required to exhale. Starting another breath before emptying is complete traps gas and raises end-expiratory alveolar pressure. This intrinsic PEEP, or auto-PEEP, can impair venous return, overload the right ventricle, lower cardiac output, and reduce cerebral perfusion.

Inspect the expiratory flow waveform: failure to return to zero before the next inspiration suggests incomplete exhalation. An expiratory hold can estimate total PEEP in a passive patient, but spontaneous effort and regional airway closure complicate interpretation. Compare peak and plateau pressures. A high peak with a much lower plateau suggests increased airway resistance from bronchospasm, secretions, or a narrow or obstructed tube; elevation of both raises concern for reduced compliance, gas trapping, or other parenchymal or chest-wall problems.

Treat Asthma and COPD While Protecting the Brain

Treat the exacerbation's cause and use inhaled bronchodilators, appropriate systemic corticosteroids, and other indicated therapy. Steroids used for an obstructive lung exacerbation are a separate indication from treating traumatic brain edema; the latter is harmful. Consider infection and aspiration where appropriate rather than assuming every wheeze requires antibiotics.

In severe obstruction, a lower set respiratory rate, an appropriately limited tidal volume, and higher inspiratory flow can lengthen expiratory time. Monitor plateau pressure, total PEEP, blood gases, and perfusion. Increasing respiratory rate reflexively to normalize CO2 can worsen air trapping and shock. A patient who deteriorates after this adjustment may improve when expiratory time is restored.

Permissive hypercapnia may be accepted in some pulmonary patients, but intracranial hypertension changes the balance because CO2 can increase cerebral blood volume. Coordinate ventilation with ICP, CPP, arterial pH, and oxygenation. Neither unlimited tidal volume to force normocapnia nor unmonitored acceptance of major hypercapnia is a safe universal solution. In a chronic CO2 retainer, baseline physiology also matters; rapid overventilation can cause marked alkalemia.

Noninvasive ventilation benefits selected COPD patients who can protect their airway, cooperate, and clear secretions. Profound coma, active vomiting, inability to handle secretions, or immediate intubation needs usually preclude it. A reassuring mask oxygen saturation does not establish airway protection or exclude worsening hypercapnia.

Pulmonary Hypertension and Right Ventricular Failure

The thin-walled right ventricle tolerates acute increases in afterload poorly. Hypoxemia, hypercapnia, acidemia, pulmonary embolism, and excessive lung distension can increase pulmonary vascular resistance. Severe systemic hypotension also reduces right coronary perfusion, worsening RV contractility. Assess echocardiographic RV size and function, septal position, volume status, and systemic perfusion; a dilated RV is not specific for an acute PE.

Avoid both indiscriminate fluid loading and severe underfilling. Excess fluid can dilate the RV further, shift the septum toward the LV, and reduce left-sided filling. Maintain systemic pressure and oxygenation, treat the precipitating cause, and coordinate inotropes or pulmonary vasodilators with specialists when indicated. Abrupt interruption of a chronic continuous pulmonary vasodilator infusion can cause dangerous rebound physiology. Verify medication delivery during transport and procedures.

Intubation is particularly hazardous in decompensated pulmonary hypertension: sedation, vasodilation, and positive pressure can combine to cause cardiovascular collapse. Prepare an expert airway and circulatory plan rather than treating intubation as a routine technical step.

What Bronchoscopy Can and Cannot Do

Flexible bronchoscopy may evaluate a suspected mucus plug, airway obstruction, hemoptysis, selected infections, or inhalation injury. It is not required routinely for every infiltrate or every episode of VAP. Scope insertion narrows the effective endotracheal tube lumen and can increase resistance, intrinsic PEEP, CO2, and ICP; suction and lavage can worsen oxygenation transiently.

Before the procedure, review oxygenation reserve, ventilation, hemodynamics, coagulation, and intracranial stability. Use appropriate preoxygenation, sedation, monitoring, and an agreed stopping plan. A patient with new lobar collapse may benefit from removal of an obstructing plug, while a patient with refractory hypoxemia and unstable ICP may require stabilization before diagnostic lavage. Interpret cultures with clinical findings because airway colonization alone does not prove pneumonia.

Sources checked October 17, 2026: GOLD COPD reports, GINA asthma guidance, and ESICM acute brain injury ventilation consensus.