Treatment of VAP should be matched to known causative bacteria. However, when VAP is first suspected, the bacteria causing infection is typically not known and broad-spectrum antibiotics are given (empiric therapy) until the particular bacterium and its sensitivities are determined. Empiric antibiotics should take into account both the risk factors a particular individual has for resistant bacteria as well as the local prevalence of resistant microorganisms. If a person has previously had episodes of pneumonia, information may be available about prior causative bacteria. The choice of initial therapy is therefore entirely dependent on knowledge of local flora and will vary from hospital to hospital. Treatment of VAP with a single antibiotic has been reported to result in similar outcomes as with a combination of more than one antibiotics, in terms of cure rates, duration of ICU stay, mortality and adverse effects.

Risk factors for infection with an MDR strain include ventilation for more than five days, recent hospitalization (last 90 days), residence in a nursing home, treatment in a hemodialysis clinic, and prior antibiotic use (last 90 days).

Possible empirical therapy combinations include (but are not limited to):

- vancomycin/linezolid and ciprofloxacin,

- cefepime and gentamicin/amikacin/tobramycin

- vancomycin/linezolid and ceftazidime

- Ureidopenicillin plus β-lactamase inhibitor such as piperacillin/tazobactam or ticarcillin/clavulanate

- a carbapenem (e.g., imipenem or meropenem)

Therapy is typically changed once the causative bacteria are known and continued until symptoms resolve (often 7 to 14 days). For patients with VAP not caused by nonfermenting Gram-negative bacilli (like Acinetobacter, Pseudomonas aeruginosa) the available evidence seems to support the use of short-course antimicrobial treatments (< or =10 days).

People who do not have risk factors for MDR organisms may be treated differently depending on local knowledge of prevalent bacteria. Appropriate antibiotics may include ceftriaxone, ciprofloxacin, levofloxacin, or ampicillin/sulbactam.

As of 2005, there is ongoing research into inhaled antibiotics as an adjunct to conventional therapy. Tobramycin and polymyxin B are commonly used in certain centres but there is no clinical evidence to support their use.

There is no readily available evidence on the route of administration and duration of antibiotics in patients with pleural empyema. Experts agree that all patients should be hospitalized and treated with antibiotics intravenously. The specific antimicrobial agent should be chosen based on Gram stain and culture, or on local epidemiologic data when these are not available. Anaerobic coverage must be included in all adults, and in children if aspiration is likely. Good pleural fluid and empyema penetration has been reported in adults for penicillins, ceftriaxone, metronidazole, clindamycin, vancomycin, gentamycin and ciprofloxacin. Aminoglycosides should typically be avoided as they have poor penetration into the pleural space. There is no clear consensus on duration of intravenous and oral therapy. Switching to oral antibiotics can be considered upon clinical and objective improvement (adequate drainage and removal of chest tube, declining CRP, temperature normalization). Oral antibiotic treatment should then be continued for another 1–4 weeks, again based on clinical, biochemical and radiological response.

Treatment is with corticosteroids and possibly intravenous immunoglobulins.

In immunocompromised patients, prophylaxis with co-trimoxazole (trimethoprim/sulfamethoxazole), atovaquone, or regular pentamidine inhalations may help prevent PCP.

Antipneumocystic medication is used with concomitant steroids in order to avoid inflammation, which causes an exacerbation of symptoms about four days after treatment begins if steroids are not used. By far the most commonly used medication is trimethoprim/sulfamethoxazole, but some patients are unable to tolerate this treatment due to allergies. Other medications that are used, alone or in combination, include pentamidine, trimetrexate, dapsone, atovaquone, primaquine, pafuramidine maleate (under investigation), and clindamycin. Treatment is usually for a period of about 21 days.

Pentamidine is less often used as its major limitation is the high frequency of side effects. These include acute pancreatic inflammation, kidney failure, liver toxicity, decreased white blood cell count, rash, fever, and low blood sugar.

Treatment depends on the underlying cause. Treatments include iced saline, and topical vasoconstrictors such as adrenalin or vasopressin. Selective bronchial intubation can be used to collapse the lung that is bleeding. Also, endobronchial tamponade can be used. Laser photocoagulation can be used to stop bleeding during bronchoscopy. Angiography of bronchial arteries can be performed to locate the bleeding, and it can often be embolized. Surgical option is usually the last resort, and can involve, removal of a lung lobe or removal of the entire lung. Non–small-cell lung cancer can also be treated with erlotinib or gefitinib. Cough suppressants can increase the risk of choking.

Proven empyema (as defined by the "golden" criteria mentioned earlier) is an indication for prompt chest tube drainage. This has been shown to improve resolution of the infection and shorten hospital admission. Data from a meta-analysis has shown that a pleural fluid pH of <7.2 is the most powerful indicator to predict the need for chest tube drainage in patients with non-purulent, culture negative fluid. Other indications for drainage include poor clinical progress during treatment with antibiotics alone and patients with a loculated pleural collection.

Because of the viscous, lumpy nature of infected pleural fluid, in combination with possible septation and loculation, it has been proposed that intrapleural fibrinolytic or mucolytic therapy might improve drainage and therefore might have a positive effect on the clinical outcome. Intrapleural fibrinolysis with urokinase decreased the need for surgery but there is a trend to increased serious side effects.

Approximately 15 to 40 percent of people require surgical drainage of the infected pleural space because of inadequate drainage due to clogging of the chest tube or loculated empyema. Patients should thus be considered for surgery if they have ongoing signs of sepsis in association with a persistent pleural collection despite drainage and antibiotics. Video-assisted thoracoscopic surgery (VATS) is used as a first-line therapy in many hospitals, although open thoracic drainage remains a frequently used alternative technique.

Prevention of VAP involves limiting exposure to resistant bacteria, discontinuing mechanical ventilation as soon as possible, and a variety of strategies to limit infection while intubated. Resistant bacteria are spread in much the same ways as any communicable disease. Proper hand washing, sterile technique for invasive procedures, and isolation of individuals with known resistant organisms are all mandatory for effective infection control. A variety of aggressive weaning protocols to limit the amount of time a person spends intubated have been proposed. One important aspect is limiting the amount of sedation that a ventilated person receives.

Other recommendations for preventing VAP include raising the head of the bed to at least 30 degrees. Antiseptic mouthwashes such as chlorhexidine may also reduce the risk of VAP, although the evidence is mainly restricted to those who have undergone cardiac surgery.

American and Canadian guidelines strongly recommend the use of supraglottic secretion drainage (SSD) Special tracheal tubes with an incorporated suction lumen as the EVAC tracheal tube form Covidien / Mallinckrodt can be used for that reason. New cuff technology based on polyurethane material in combination with subglottic drainage (SealGuard Evac tracheal tube from Covidien/Mallinckrodt)showed significant delay in early and late onset of VAP.

A recent clinical trial indicates that the use of silver-coated endotracheal tubes may also reduce the incidence of VAP. There is tentative evidence that the use of probiotics may reduced the likelihood of getting VAP, however it is unclear if probiotics affect ICU or in-hospital death.

Antibiotics improve outcomes in those with bacterial pneumonia. Antibiotic choice depends initially on the characteristics of the person affected, such as age, underlying health, and the location the infection was acquired. In the UK, treatment before culture results with amoxicillin is recommended as the first line for community-acquired pneumonia, with doxycycline or clarithromycin as alternatives. In North America, where the "atypical" forms of community-acquired pneumonia are more common, macrolides (such as azithromycin or erythromycin), and doxycycline have displaced amoxicillin as first-line outpatient treatment in adults. In children with mild or moderate symptoms, amoxicillin remains the first line. The use of fluoroquinolones in uncomplicated cases is discouraged due to concerns about side-effects and generating resistance in light of there being no greater clinical benefit.

For those who require hospitalization and caught their pneumonia in the community the use of a β-lactam such as cephazolin plus macrolide such as azithromycin or a fluoroquinolones is recommended. The addition of corticosteroids also appears to improve outcomes.

The duration of treatment has traditionally been seven to ten days, but increasing evidence suggests that shorter courses (three to five days) are similarly effective. Recommendations for hospital-acquired pneumonia include third- and fourth-generation cephalosporins, carbapenems, fluoroquinolones, aminoglycosides, and vancomycin. These antibiotics are often given intravenously and used in combination. In those treated in hospital, more than 90% improve with the initial antibiotics.

Treatment of CAP in children depends on the child's age and the severity of illness. Children under five are not usually treated for atypical bacteria. If hospitalization is not required, a seven-day course of amoxicillin is often prescribed, with co-trimaxazole an alternative when there is allergy to penicillins. Further studies are needed to confirm the efficacy of newer antibiotics. With the increase in drug-resistant Streptococcus pneumoniae, antibiotics such as cefpodoxime may become more popular. Hospitalized children receive intravenous ampicillin, ceftriaxone or cefotaxime, and a recent study found that a three-day course of antibiotics seems sufficient for most mild-to-moderate CAP in children.

Oral antibiotics, rest, simple analgesics, and fluids usually suffice for complete resolution. However, those with other medical conditions, the elderly, or those with significant trouble breathing may require more advanced care. If the symptoms worsen, the pneumonia does not improve with home treatment, or complications occur, hospitalization may be required. Worldwide, approximately 7–13% of cases in children result in hospitalization, whereas in the developed world between 22 and 42% of adults with community-acquired pneumonia are admitted. The CURB-65 score is useful for determining the need for admission in adults. If the score is 0 or 1, people can typically be managed at home; if it is 2, a short hospital stay or close follow-up is needed; if it is 3–5, hospitalization is recommended. In children those with respiratory distress or oxygen saturations of less than 90% should be hospitalized. The utility of chest physiotherapy in pneumonia has not yet been determined. Non-invasive ventilation may be beneficial in those admitted to the intensive care unit. Over-the-counter cough medicine has not been found to be effective nor has the use of zinc in children. There is insufficient evidence for mucolytics.

In 2001 the American Thoracic Society, drawing on the work of the British and Canadian Thoracic Societies, established guidelines for the management of adult CAP dividing patients into four categories based on common organisms:

- Healthy outpatients without risk factors: This group (the largest) is composed of otherwise-healthy patients without risk factors for DRSP, enteric gram-negative bacteria, "pseudomonas" or other, less-common, causes of CAP. Primary microoganisms are viruses, atypical bacteria, penicillin-sensitive "streptococcus pneumoniae" and "haemophilus influenzae". Recommended drugs are macrolide antibiotics, such as azithromycin or clarithromycin, for seven to ten days.

- Outpatients with underlying illness or risk factors: Although this group does not require hospitalization, patients have underlying health problems (such as emphysema or heart failure) or are at risk for DRSP or enteric gram-negative bacteria. They are treated with a quinolone active against "streptococcus pneumoniae" (such as levofloxacin) or a β-lactam antibiotic (such as cefpodoxime, cefuroxime, amoxicillin or amoxicillin/clavulanic acid) and a macrolide antibiotic, such as azithromycin or clarithromycin, for seven to ten days.

- Hospitalized patients without risk for "pseudomonas": This group requires intravenous antibiotics, with a quinolone active against "streptococcus pneumoniae" (such as levofloxacin), a β-lactam antibiotic (such as cefotaxime, ceftriaxone, ampicillin/sulbactam or high-dose ampicillin plus a macrolide antibiotic (such as azithromycin or clarithromycin) for seven to ten days.

- Intensive-care patients at risk for "pseudomonas aeruginosa": These patients require antibiotics targeting this difficult-to-eradicate bacterium. One regimen is an intravenous antipseudomonal beta-lactam such as cefepime, imipenem, meropenem or piperacillin/tazobactam, plus an IV antipseudomonal fluoroquinolone such as levofloxacin. Another is an IV antipseudomonal beta-lactam such as cefepime, imipenem, meropenem or piperacillin/tazobactam, plus an aminoglycoside such as gentamicin or tobramycin, plus a macrolide (such as azithromycin) or a nonpseudomonal fluoroquinolone such as ciprofloxacin.

For mild-to-moderate CAP, shorter courses of antibiotics (3–7 days) seem to be sufficient.

Some patients with CAP will be at increased risk of death despite antimicrobial treatment. A key reason for this is the host's exaggerated inflammatory response. On one hand it is required to control the infection but on the other, it leads to bystander tissue damage. As a consequence of this recent research focuses on immunomodulatory therapy that can modulate the immune response to reduce injury to the lung and other affected organs such as the heart. Although the evidence for these agents has not resulted in their routine use, there potential benefits are highly promising.

Most patients recover with corticosteroid therapy. A standardized approach to dosing starting at 0.75 mg/kg and weaning over 24 weeks has been shown to reduce total corticosteroid exposure without affecting outcome.

About two thirds of patients recover with corticosteroid therapy: the usual corticosteroid administered is prednisolone in Europe and prednisone in the USA; these differ by only one functional group and have the same clinical effect. The corticosteroid is initially administered in high dosage, typically 50 mg per day tapering down to zero over a six-month to one-year period. If the corticosteroid treatment is halted too quickly the disease may return. Other medications must be taken to counteract side effects of the steroid.

Usually initial therapy is empirical. If sufficient reason to suspect influenza, one might consider oseltamivir. In case of legionellosis, erythromycin or fluoroquinolone.

A third generation cephalosporin (ceftazidime) + carbapenems (imipenem) + beta lactam & beta lactamase inhibitors (piperacillin/tazobactam)

Antibiotics are the treatment of choice for bacterial pneumonia, with ventilation (oxygen supplement) as supportive therapy. The antibiotic choice depends on the nature of the pneumonia, the microorganisms most commonly causing pneumonia in the geographical region, and the immune status and underlying health of the individual. In the United Kingdom, amoxicillin is used as first-line therapy in the vast majority of patients acquiring pneumonia in the community, sometimes with added clarithromycin. In North America, where the "atypical" forms of community-acquired pneumonia are becoming more common, clarithromycin, azithromycin, or fluoroquinolones as single therapy have displaced the amoxicillin as first-line therapy.

Local patterns of antibiotic-resistance always need to be considered when initiating pharmacotherapy. In hospitalized individuals or those with immune deficiencies, local guidelines determine the selection of antibiotics.

"Streptococcus pneumoniae" — amoxicillin (or erythromycin in patients allergic to penicillin); cefuroxime and erythromycin in severe cases.

"Staphylococcus aureus" — flucloxacillin (to counteract the organism's β-lactamase).

When eosinophilic pneumonia is related to an illness such as cancer or parasitic infection, treatment of the underlying cause is effective in resolving the lung disease. When due to AEP or CEP, however, treatment with corticosteroids results in a rapid, dramatic resolution of symptoms over the course of one or two days. Either intravenous methylprednisolone or oral prednisone are most commonly used. In AEP, treatment is usually continued for a month after symptoms disappear and the x-ray returns to normal (usually four weeks total). In CEP, treatment is usually continued for three months after symptoms disappear and the x-ray returns to normal (usually four months total). Inhaled steroids such as fluticasone have been used effectively when discontinuation of oral prednisone has resulted in relapse.

Because EP affects the lungs, individuals with EP have difficulty breathing. If enough of the lung is involved, it may not be possible for a person to breathe without support. Non-invasive machines such as a bilevel positive airway pressure machine may be used. Otherwise, placement of a breathing tube into the mouth may be necessary and a ventilator may be used to help the person breathe.

Fungal pneumonia can be treated with antifungal drugs and sometimes by surgical debridement.

Patients with HCAP are more likely than those with community-acquired pneumonia to receive inappropriate antibiotics that do not target the bacteria causing their disease.

In 2002, an expert panel made recommendations about the evaluation and treatment of probable nursing home-acquired pneumonia. They defined probably pneumonia, emphasized expedite antibiotic treatment (which is known to improve survival) and drafted criteria for the hospitalization of willing patients.

For initial treatment in the nursing home, a fluoroquinolone antibiotic suitable for respiratory infections (moxifloxacin, for example), or amoxicillin with clavulanic acid plus a macrolide has been suggested. In a hospital setting, injected (parenteral) fluoroquinolones or a second- or third-generation cephalosporin plus a macrolide could be used. Other factors that need to be taken into account are recent antibiotic therapy (because of possible resistance caused by recent exposure), known carrier state or risk factors for resistant organisms (for example, known carrier of MRSA or presence of bronchiectasis predisposing to Pseudomonas aeruginosa), or suspicion of possible Legionella pneumophila infection (legionnaires disease).

In 2005, the American Thoracic Society and Infectious Diseases Society of America have published guidelines suggesting antibiotics specifically for HCAP. The guidelines recommend combination therapy with an agent from each of the following groups to cover for both "Pseudomonas aeruginosa" and MRSA. This is based on studies using sputum samples and intensive care patients, in whom these bacteria were commonly found.

- cefepime, ceftazidime, imipenem, meropenem or piperacillin–tazobactam; plus

- ciprofloxacin, levofloxacin, amikacin, gentamicin, or tobramycin; plus

- linezolid or vancomycin

In one observational study, empirical antibiotic treatment that was not according to international treatment guidelines was an independent predictor of worse outcome among HCAP patients.

Guidelines from Canada suggest that HCAP can be treated like community-acquired pneumonia with antibiotics targeting Streptococcus pneumoniae, based on studies using blood cultures in different settings which have not found high rates of MRSA or Pseudomonas.

Besides prompt antibiotic treatment, supportive measure for organ failure (such as cardiac decompensation) are also important. Another consideration goes to hospital referral; although more severe pneumonia requires admission to an acute care facility, this also predisposes to hazards of hospitalization such as delirium, urinary incontinence, depression, falls, restraint use, functional decline, adverse drug effects and hospital infections. Therefore, mild pneumonia might be better dealt with inside the long term care facility. In patients with a limited life expectancy (for example, those with advanced dementia), end-of-life pneumonia also requires recognition and appropriate, palliative care.

General treatment principles are removal from exposure, protection of the airway (i.e., preemptive intubation), and treatment of hypoxemia. Concomitant airway injury with acute bronchospasm often warrants treatment with bronchodilators because of the airway obstruction.

A beneficial role for corticosteroids has not been established by controlled trials in humans. Despite the lack of controlled evidence of efficacy, anecdotal reports of benefits from systemic corticosteroid use continue to appear.

Prophylactic antibiotic drugs have not proved to be efficacious in toxic lung injury. Antibiotics should be reserved for those patients with clinical evidence of infection.

The course of treatment of fire breather's pneumonia remains controversial. Administration of bronchodilators, corticosteroids, and prophylactic antibiotics to prevent secondary infection, is a common course of treatment. Some studies suggest that steroids may improve outcomes in severely affected individuals, yet these data are only based on a limited number of patients. The use of gastric decontamination to prevent subsequent pulmonary injury from hydrocarbon ingestion is controversial. It may have potential benefit in large (> 30 cc), intentional ingestion of compounds with systemic toxicity.

Prognosis after peak symptoms is typically good, with most patients making a full recovery in weeks to months.

Treatment depends on the underlying cause of the pleural effusion.

Therapeutic aspiration may be sufficient; larger effusions may require insertion of an intercostal drain (either pigtail or surgical). When managing these chest tubes, it is important to make sure the chest tubes do not become occluded or clogged. A clogged chest tube in the setting of continued production of fluid will result in residual fluid left behind when the chest tube is removed. This fluid can lead to complications such as hypoxia due to lung collapse from the fluid, or fibrothorax if scarring occurs. Repeated effusions may require chemical (talc, bleomycin, tetracycline/doxycycline), or surgical pleurodesis, in which the two pleural surfaces are scarred to each other so that no fluid can accumulate between them. This is a surgical procedure that involves inserting a chest tube, then either mechanically abrading the pleura or inserting the chemicals to induce a scar. This requires the chest tube to stay in until the fluid drainage stops. This can take days to weeks and can require prolonged hospitalizations. If the chest tube becomes clogged, fluid will be left behind and the pleurodesis will fail.

Pleurodesis fails in as many as 30% of cases. An alternative is to place a PleurX Pleural Catheter or Aspira Drainage Catheter. This is a 15Fr chest tube with a one-way valve. Each day the patient or care givers connect it to a simple vacuum tube and remove from 600 to 1000 mL of fluid, and can be repeated daily. When not in use, the tube is capped. This allows patients to be outside the hospital. For patients with malignant pleural effusions, it allows them to continue chemotherapy, if indicated. Generally, the tube is in for about 30 days and then it is removed when the space undergoes a spontaneous pleurodesis.

Retaining secretions in the airways can worsen hypoxia and lead to infections. Thus, an important part of treatment is pulmonary toilet, the use of suction, deep breathing, coughing, and other methods to remove material such as mucus and blood from the airways. Chest physical therapy makes use of techniques such as breathing exercises, stimulation of coughing, suctioning, percussion, movement, vibration, and drainage to rid the lungs of secretions, increase oxygenation, and expand collapsed parts of the lungs. People with pulmonary contusion, especially those who do not respond well to other treatments, may be positioned with the uninjured lung lower than the injured one to improve oxygenation. Inadequate pulmonary toilet can result in pneumonia. People who do develop infections are given antibiotics. No studies have yet shown a benefit of using antibiotics as a preventative measure before infection occurs, although some doctors do recommend prophylactic antibiotic use even without scientific evidence of its benefit. However, this can cause the development of antibiotic resistant strains of bacteria, so giving antibiotics without a clear need is normally discouraged. For people who are at especially high risk of developing infections, the sputum can be cultured to test for the presence of infection-causing bacteria; when they are present, antibiotics are used.

Pain control is another means to facilitate the elimination of secretions. A chest wall injury can make coughing painful, increasing the likelihood that secretions will accumulate in the airways. Chest injuries also contribute to hypoventilation (inadequate breathing) because the chest wall movement involved in breathing adequately is painful. Insufficient expansion of the chest may lead to atelectasis, further reducing oxygenation of the blood. Analgesics (pain medications) can be given to reduce pain. Injection of anesthetics into nerves in the chest wall, called nerve blockade, is another approach to pain management; this does not depress respiration the way some pain medications can.

The administration of fluid therapy in individuals with pulmonary contusion is controversial. Excessive fluid in the circulatory system (hypervolemia) can worsen hypoxia because it can cause fluid leakage from injured capillaries (pulmonary edema), which are more permeable than normal. However, low blood volume (hypovolemia) resulting from insufficient fluid has an even worse impact, potentially causing hypovolemic shock; for people who have lost large amounts of blood, fluid resuscitation is necessary. A lot of the evidence supporting the idea that fluids should be withheld from people with pulmonary contusion came from animal studies, not clinical trials with humans; human studies have had conflicting findings on whether fluid resuscitation worsens the condition. Current recommendations suggest giving enough fluid to ensure sufficient blood flow but not giving any more fluid than necessary. For people who do require large amounts of intravenous fluid, a catheter may be placed in the pulmonary artery to measure the pressure within it. Measuring pulmonary artery pressure allows the clinician to give enough fluids to prevent shock without exacerbating edema. Diuretics, drugs that increase urine output to reduce excessive fluid in the system, can be used when fluid overload does occur, as long as there is not a significant risk of shock. Furosemide, a diuretic used in the treatment of pulmonary contusion, also relaxes the smooth muscle in the veins of the lungs, thereby decreasing pulmonary venous resistance and reducing the pressure in the pulmonary capillaries.

Different treatments have been used to manage pulmonary interstitial emphysema with variable success. Admission/transfer to a neonatal intensive care unit (NICU) is common and expected for patients with PIE.

Treatments include:

- Lateral decubitus position with the affected side down

- High-frequency ventilation

- Lobectomy

- Selective Main Bronchial Intubation and Occlusion

Treatment of bronchiectasis includes controlling infections and bronchial secretions, relieving airway obstructions, removal of affected portions of lung by surgical removal or artery embolization and preventing complications. The prolonged use of antibiotics prevents detrimental infections and decreases hospitalizations in people with bronchiectasis, but also increases the risk of people becoming infected with drug-resistant bacteria.

Other treatment options include eliminating accumulated fluid with postural drainage and chest physiotherapy. Postural drainage techniques, aided by physiotherapists and respiratory therapists, are an important mainstay of treatment. Airway clearance techniques appear useful.

Surgery may also be used to treat localized bronchiectasis, removing obstructions that could cause progression of the disease.

Inhaled steroid therapy that is consistently adhered to can reduce sputum production and decrease airway constriction over a period of time, and help prevent progression of bronchiectasis. This is not recommended for routine use in children. One commonly used therapy is beclometasone dipropionate.

Although not approved for use in any country, mannitol dry inhalation powder, has been granted orphan drug status by the FDA for use in people with bronchiectasis and with cystic fibrosis.