Respiratory Flashcards
Which of the following statements regarding haemoglobin and oxygen is true?
A. Normally, approximately 85% of oxygen in the blood is carried on haemoglobin, and 15% is transported in a dissolved state.
B. Shift of the oxygen-haemoglobin dissociation curve to the right can be caused by decreased carbon dioxide.
C. Each gram of haemoglobin can bind with a maximum of 1.34 millilitres of oxygen.
D. Increased pH of the blood shifts the oxygen-haemoglobin dissociation curve to the right.
C. Each gram of haemoglobin can bind with a maximum of 1.34 millilitres of oxygen.
O2 saturation of arterial blood with PO2 of 100 mm Hg is about 97.5%, whereas that of mixed venous blood with a PO2 of 40 mm Hg is about 75%.
The O2-Hg dissociation curve is moved to the right by increased H+ concentration / decreased pH, increased PCO2, increased temperature and increased 2,3-DPG in RBC.
What is the term used for the amount of air that remains in the lungs at the end of normal expiration?
A. Functional residual capacity.
B. Expiratory reserve volume.
C. Vital capacity.
D. Residual volume.
A. Functional residual capacity.
Expiratory reserve volume (ERV): the additional air that can be forcibly exhaled after the expiration of a normal tidal volume.
Vital capacity (VC): the total amount of air that can be expired after fully inhaling.
Vital capacity (VC): the total amount of air that can be expired after fully inhaling.
The lung has important metabolic functions in addition to its gas exchange functions. Which of the following substances is NOT affected by passage through the pulmonary circulation?
A. Angiotensin I.
B. Bradykinin.
C. Prostaglandin E2.
D. Histamine.
D. Histamine.
Angiotensin I is converted to angiotensin II by ACE.
Bradykinin is up to 80% inactivated.
Prostaglandins E2 and F2a are almost completely removed.
Which of the following is a role of surfactant?
A. Reduces lung compliance.
B. Keeps alveoli dry.
C. Promotes laminar flow.
D. Promotes atelectasis.
B. Keeps alveoli dry - surface tension of the curved alveolar surface reduces hydrostatic pressure in the tissue outside the capillaries.
Pulmonary surfactant: phospholipid (including dipalmitoyl phosphatidylcholine (DPPC); synthesized by Type II cells from fatty acids that are either extracted from blood or synthesized in the lung itself; three primary roles = lowers surface tension in alveoli (increases compliance of the lung and reduces work of expanding lung), promotes stability of the alveoli, and keeps the alveoli dry.
Absence of surfactant results in reduced lung compliance, alveolar atelectasis and tendency to pulmonary oedema.
Which of the following is an example of an obstructive pulmonary disease?
A. Equine asthma.
B. Pleural effusion.
C. Pulmonary fibrosis.
D. Ascites.
A. Equine asthma.
Pulmonary fibrosis, pulmonary effusion and ascites are examples of restrictive pulmonary diseases.
A standing procedure for laryngoplasty in horses with recurrent laryngeal paralysis was recently described by Rossignol et al, 2015. What was the reported long term success rate of this procedure in terms of improvement in respiration?
A. 96% (68/71 horses).
B. 99% (70/71 horses).
C. 53% (38/71 horses).
D. 89% (63/71 horses).
A. 96% (68/71 horses).
Ref: Rossignol et al, Vet Surg, 2015; 44:341-347.
The above is an image taken from a Thoroughbred racehorse during maximal exercise on a treadmill. Which of the following parameters are likely to be decreased in this horse compared to a horse with normal upper airway function at the same point during an exercise test (Allen and Franklin, 2013)?
A. End-tidal carbon dioxide.
B. Alveolar resistance.
C. Peak treadmill speed.
D. Minute ventilation.
D. Minute ventilation.
This horse has moderately severe palatal instability. In this study there was a trend for minute ventilation, tidal volume, oxygen consumption and CO2 production to decrease with increasing palatal dysfunction, although statistically significant differences were only seen with DDSP. End-tidal CO2 and end-tidal O2 dec with increasing obstruction.
Ref: Allen and Franklin, Equine Vet J, 2013:350-354.
Owners frequently present horses to veterinary clinics for evaluation after hearing abnormal breathing noises during exercise. Which of the following owner-reported noises has the highest specificity for diagnosis of an upper respiratory tract disorder in horses according to Witte et al, 2011?
A. Rough noise.
B. Gurgling.
C. Whistling.
D. Rattling.
C. Whistling.
82% of horses with a reported noise had an upper airway abnormalities on dynamic endoscopy. Whistling and roaring showed the highest specificity (80%) for laryngeal dysfunction. Gurgling, rattling and rough noises were associated with palatal dysfunction.
Ref: Witte et al, Equine Vet J, 2011; 43:9-17.
Tongue ties are commonly used in racehorses, however there is little scientific evidence for their use. What did Chalmers et al, 2013, prove with regard to the influence of tongue ties on laryngohyoid morphology in their ultrasonographic study?
A. The tongue tie resulted in a decrease in depth of the thyroid cartilage and basihyoid bone when compared to horses with only a halter and leadrope on.
B. The tongue tie resulted in an increase in depth of the thyroid cartilage and basihyoid bone when compared to horses with only a halter and leadrope on.
C. The tongue tie resulted in a decrease in lingual process depth when compared to horses with only a halter and leadrope on.
D. The tongue tie did not significantly affect lingual process depth when compared to horses with only a halter and leadrope on.
A. The tongue tie resulted in a decrease in depth of the thyroid cartilage and basihyoid bone when compared to horses with only a halter and leadrope on.
Ref: Chalmers et al, Equine Vet J, 2013; 45:711-714.
Exercise induced pulmonary haemorrhage (EIPH) is an issue of concern with regards to public perception of animal welfare in the sport of racing, however debate exists within and between equine industry bodies as to the clinical significance of this disorder. According to Morley et al, 2015 what is the impact of EIPH on the performance of Thoroughbred racehorses?
A. Horses without EIPH are >4 times more likely to win races and finish an average of 2 lengths ahead of horses with EIPH.
B. Horses without EIPH are >2 times more like to win races and finish an average of 1 length ahead of horses with EIPH.
C. Horses without EIPH have higher lifetime earnings but do not finish in the top 3 positions any more frequently than horses with EIPH.
D. Horses without EIPH do not have higher lifetime earnings but do finish in the top 3 positions more frequently than horses with EIPH.
A. Horses without EIPH are >4 times more likely to win races and finish an average of 2 lengths ahead of horses with EIPH.
No association was identified regarding finishing in the top 3 positions or earning money when analysed as a continuous variable or analysed as any winnings vs. none.
Ref: Morely et al, Equine Vet J, 2015; 47:358-365.
Exercise induced pulmonary haemorrhage (EIPH) induces gross and histologic changes in the lungs of horses overtime. You perform a post-mortem on an ex-racehorse that was retired 18 months ago following two episodes of severe bilateral epistaxis during racing. Which of the following lesions could you expect to find in his lungs?
A. Breaks in the capillary endothelium and basement membrane, interstitial and intra-alveolar accumulations of erythrocytes, and interstitial oedema.
B. Extensive remodelling of small pulmonary arteries characterised by accumulation of adventitial collagen and smooth muscle hyperplasia.
C. Firm parenchyma that does not fully deflate following excision in the cranioventral lung lobes.
D. Pleural discoloration, pleural fibrosis and venous remodelling.
D. Pleural discoloration, pleural fibrosis and venous remodelling.
The other options are incorrect as A. describes changes seen after an acute EIPH episode, B. the changes described occur in veins not arteries and C. horses with EIPH have lesions in the caudodorsal not cranioventral lungs.
Ref: ACVIM Consensus Statement EIPH, 2015.
The above horse presents to your hospital in acute respiratory distress. The horse has a history of intermittent coughing and heavy breathing (especially when stabled at horse shows) of 3 years duration. Your physical examination reveals the pictured abnormality, cyanotic mucous membranes, tachypnoea (60bpm), tachycardia (72bpm), normal rectal temperature (37.3C) and severe bilateral wheezes. Complete blood count reveals moderate neutrophilia and lymphopaenia with normal white blood cell morphology. You are unable to perform pulmonary function testing, transtracheal wash or broncholaveolar lavage due to the degree of respiratory distress therefore treat her based on the most likely diagnosis with intravenous dexamethasone and intranasal oxygen. Which of the following would be the best additional medication to give this horse immediately (Lagarde et al, 2014)?
A. Clenbuterol per os.
B. Salmeterol via metered dose inhaler.
C. N-butylscopolammonium bromide via intravenous injection.
D. Atropine via intravenous injection.
C. N-butylscopolammonium bromide via intravenous injection.
N-butylscopolammonium bromide and atropine both induced bronchodilation and improved lung function in horses in an acute episode of RAO. Atropine caused colic and pupillary dilation, whereas buscopan did not, therefore is safer to use.
Clenbuterol and salmeterol have delayed onset therefore are not as ideal for reversal of acute respiratory obstruction when a horse is in this degree of respiratory distress.
Ref: Lagarde et al, Equine Vet J, 2014; 46:474-478.
A racehorse trainer calls you as he has been observing more than the usual amount of respiratory disease (coughing, snotty noses, getting puffed easily) in his horses in work this season. He asks you to scope every horse in his barn and tell him which ones he needs to treat for inflammatory airway disease. He refuses to allow you to perform bronchoalveolar lavage and fluid cytology as he doesn’t believe in that new-fangled laboratory stuff. With reference to the work by Koblinger et al, 2011, how do you interpret your endoscopic findings?
A. Pharyngeal and tracheal mucous are highly correlated with inflammatory airway disease.
B. Pharyngitis is highly correlated with inflammatory airway disease.
C. Tracheal septum thickness is negative correlated with inflammatory airway disease.
D. Tracheal and bronchial mucus are highly correlated with inflammatory airway disease.
D. Tracheal and bronchial mucus are highly correlated with inflammatory airway disease.
Tracheal mucus (P < .001), tracheal septum thickness (P = .036), and bronchial mucus (P = .037) were significantly increased in horses with severe inflammation BALs. BAL neutrophils percentage was correlated with tracheal mucus (rs = 0.41, P < .001), bronchial mucus (rs = 0.27, P = .003), and had a weak negative correlation with pharyngitis (rs = 0.25, P = .004). Lower airway endoscopy scores are reflective of lower airway inflammation; however, upper and lower airways are independent in terms of severity of inflammation.
Ref: Koblinger et al, J Vet Intern Med, 2011; 25:1118-1126.
Cytokine mRNA expression has been measured in the bronchoalveolar lavage fluid (BALF) of horses with inflammatory airway disease (IAD). What did Beekman et al, 2012 determine with regards to cytokine expression in BALF of horses with neutrophilic and masocytic IAD?
A. Cytokines from the Th1 family play a key role in IAD.
B. Cytokines from the Th2 family play a key role in IAD.
C. Cytokines from the Th2 family play a key role in neutrophilic IAD and cytokines from the Th1 family play a key role in mastocytic IAD.
D. Cytokines from the Th1 family play a key role in neutrophilic IAD and cytokines from the Th2 family play a key role in mastocytic IAD.
B. Cytokines from the Th2 family play a key role in IAD.
IL-5, IL-1b, IL-6, IL-8, and IL-10 mRNA expression was upregulated in the IAD-total group. The IAD-Neutro group showed increased expression of IL-17, IL-8, and IL-5 and a decreased expression of IL-4 compared with the IAD-Mast group.
Cytokines from the Th2 family plays a key role in IAD and a different pathophysiology may be involved in mast cell versus neutrophil BALF accumulation in IAD horses.
Ref: Beekman et al, J Vet Intern Med, 2012;26:153–161.
Lucky, a 5 year old Quarter Horse gelding used for barrel racing presents to your clinic for evaluation and treatment of colic. Instead you notice the abnormalities above! You ask a few questions are told he has only just been bought by his current owner and was transported from his previous home 2 days ago. Which of the following risk factors is most likely to have been involved in the development of disease in this horse (Padalino et al, 2016)?
A. Breed.
B. Transport with a commercial hauler (as opposed to private horse owner).
C. 12 hour journey duration.
D. Lack of open windows in trailer/horse truck/float during transportation.
C. 12 hour journey duration.
The type of health problem was associated with journey duration (P<0.001) and horse breed (P = 0.001). Injuries were more likely to occur on short journeys, whereas more severe illnesses (gastrointestinal and respiratory problems, and death or euthanasia) were more likely to occur on long journeys (8-24h or >24h vs <8h). Using Standardbreds as the reference group, Thoroughbreds, Arabians and Warmbloods were more likely to experience a severe illness than an injury. Type of vehicle and operator, number of horses on vehicle, sex of horse, use of horse and level of competition were not associated with adverse events.
Ref: Padalino et al, Equine Vet J, 2016; 0:1-5.
