Lecture 30 11/21/24 Flashcards
What is pulmonary edema?
abnormal accumulation of liquid and solute in the interstitial tissues, airways, and alveoli of the lung
What are the characteristics of pulmonary edema?
-not a disease, but a consequence
-can be cardiogenic or non-cardiogenic
What is the sequence of edema accumulation?
-fluid accumulates faster than it can be absorbed
-fluid in the alveoli leads to V/Q mismatch and hypoxemia
What are the pathophysiologic causes of pulmonary edema?
-increased pulmonary capillary hydrostatic pressure
-decreased plasma oncotic pressure
-decreased capillary wall integrity
-impaired lymphatic functions
What can cause increased hydrostatic pressure?
-left heart failure
-overhydration
-venous obstruction and compression
What can cause decreased plasma oncotic pressure?
-hypoalbuminemia
-overhydration
What can cause altered lymphatic drainage?
-cancer
-lymphatic hypoplasia/aplasia
-lymphangitis (from tick-borne disease)
What can cause altered capillary membrane permeability?
-electric cord shock
-infection/sepsis
-smoke/irritants
-gastric fluid aspiration
What are the predisposing factors for non-cardiogenic edema development?
-neurogenic pulmonary edema
-post-obstructive pulmonary edema
-systemic disease leading to ARDS
-direct pulmonary injury
-profound hypoalbuminemia
-impaired lymphatic drainage
-drowning
-transfusion-related
-pulmonary thromboembolism
-high altitude
What are the consequences of edema?
-pulmonary fluid accumulation
-atelectasis
-decreased compliance
-V/Q inequality
-hypoxemia
What are the clinical signs of pulmonary edema?
-crackles/harsh bronchovesicular sounds
-moist cough that may produce foam
-tachypnea
-orthopnea
-dyspnea
-open mouth breathing
-cyanosis
-hemoptysis
How is pulmonary edema diagnosed?
-history
-physical exam
-blood work
-blood gas
-radiology
Which signs on radiology are indicative of pulmonary edema?
-unstructured interstitial or peribronchial pattern
-patchy infiltrates
-caudodorsal fields affected
Which diagnostics are used to determine whether or not pulmonary edema results from heart disease?
-auscultation
-ECG
-TFAST
-echo
-NT-proBNP
What are the treatment steps for pulmonary edema?
-cage rest/reduce stress; use sedatives PRN
-improve oxygen with supplemental O2 and bronchodilators
-decrease hydrostatic pressure with diuretics and vasodilators
-identify and treat underlying disease
-supportive care
-intubation and ventilation for severe cases
What is ARDS?
acute respiratory failure due to non-cardiogenic edema and inflammation
How does ARDS differ from acute lung injury?
acute lung injury is a less severe version of ARDS
What are the risk factors for ARDS?
-risk factors for non-cardiogenic pulmonary edema
-injury to vascular endothelium
–aspiration pneumonia
–bacterial pneumonia
–sepsis
–trauma
–shock
What are the clinical signs of ARDS/ALI?
-rapid onset of resp. signs
-bilateral pulmonary infiltrates on rads
-no evidence of left atrial hypertension
What are the characteristics of PaO2:FiO2 ratio?
-ratio between arterial O2 and inspired O2
-PaO2 measured on blood gas
-severe ARDS ratio = <100 mmHg
-moderate ARDS ratio = 100-200 mmHg
-mild ARDS/ALI ratio = 200-300 mmHg
How is ARDS/ALI treated?
-treat underlying disease
-supplemental O2
-ventilator for resp. support
-supportive care
-refer case to emergency/critical care facility
What are the characteristics of the pleural space?
-serous membrane
-mediastinum is incomplete
-normal pleural fluid is produced by transudation
Why is it important that normal intrathoracic pressure is negative?
negative intrathoracic pressure keeps the alveoli open in health
What can cause pneumothorax?
-leakage from inside airway
-air from the outside
-trauma
-bullae in the lung
-iatrogenic
-neoplasia
-spontaneous pneumothorax
What is the treatment for pneumothorax?
-remove air
-continuous drainage if needed
-possibly surgery
What are the potential etiologies of pleural effusion?
-increased hydrostatic pressure
-decreased oncotic pressure
-increased capillary membrane permeability
-lymphatic obstruction
What happens as pleural effusion forms?
there is a gradual collapse of lung parenchyma and an increase in intrathoracic pressure
What can cause pleural effusion?
-CHF
-pneumonia
-malignancy
-atelectasis
-hypoalbuminemia
-diaphragmatic defect
-thoracic duct rupture/disease
-idiopathic chylothorax
What are the clinical signs of pleural effusion?
-restrictive breathing pattern
-rapid, shallow breathing
-resp. distress
-strong abdominal component to breathing
-muffled lung sounds
Which aspects of the physical exam are most important when dealing with pleural effusion?
-breathing pattern
-percussion
-auscultation
What are the characteristics of diagnostic thoracocentesis?
-often done before rads to stabilize patient
-not a benign procedure
-down with aseptic technique
-should provide supplemental oxygen
-insert needle anterior to rib
-remove air or fluid
What is the diagnostic approach to pleural effusion?
-do not stress animal
-TFAST/ultrasound
-radiology
-thoracocentesis before or after rads
What should be done after removing air/fluid via thoracocentesis?
-re-radiograph
-remove remaining fluid if present
-determine underlying disease
What is the therapy for pleural effusion patients?
-oxygen
-temporary thoracocentesis/repeated as necessary
-chest tubes in severe patients
Which conditions are responsible for the majority of pleural effusion in cats?
cardiac disease and neoplasia
What are the causes of hemothorax?
-coagulopathy
-trauma/rib fracture
-cancer
How does hematocrit help to indicate hemothorax?
-pleural effusion has HCT greater than 20%
-HCT of pleural effusion is greater than 50% of patient’s peripheral HCT
What are the causes of pure transudates?
-hypoproteinemia
-early heart failure
What are the causes of modified transudates?
-feline cardiomyopathy
-diaphragmatic hernia
What are the causes of non-septic exudates?
-neoplasia
-lung lobe torsion
-FIP
-pancreatitis
What clinical signs are seen in patients with septic exudate?
-systemic signs of illness
-inflammatory leukogram
-fever
-degenerative neutrophils and bacteria on cytology
What are the characteristics of pyothorax?
-purulent exudate in pleural cavity
-result of bacterial invasion
What are the potential etiologies of pyothorax?
-migrating foreign bodies
-bite wounds
-extension from lungs
-esophageal perforation
-parasitic migration
-hematogenous spread
-iatrogenic
Which organisms are typically involved in pyothorax?
-anaerobes
-Actinomyces
-Norcardia
-Pasteurella
How is pyothorax diagnosed?
-ultrasound
-radiology
-thoracocentesis
-cytology
-culture and sensitivity
-blood work
-CT scan
What is the treatment for pyothorax?
-oxygen
-IV fluids
-nutrition
-systemic antibiotics
-drainage
-thoracotomy tubes
-surgery
What are the sequelae of of pyothorax?
-constrictive pleuritis
-adhesions
-abscessation
What are the characteristics of chylothorax?
-contains chyle/lymphatic fluid from the gut
-effusion is a mixture of intestinal and thoracic lymph
What are the causes of chylothorax?
-congenital abnormalities of thoracic duct
-cranial mediastinal masses/neoplasia
-fungal granulomas
-heart disease
-trauma
-lung lobe torsion
-thrombosis
-idiopathic
How is chylothorax diagnosed?
-pleural disease signs
-radiology
-thoracocentesis
-fluid analysis; cytology and triglyceride on fluid and serum
What is the treatment for chylothorax?
-drainage
-low fat diet
-rutin/octreotide medications
-surgery
What are the surgical options to treat chylothorax?
-ligation of thoracic duct
-shunts
-omental drainage
-pericardectomy
What are the long term sequelae of chylothorax?
-loss of fluids, proteins, vitamins, and electrolytes when drained
-constrictive pleuritis
-pneumothorax from constant draining
-patient stress from constant draining
