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=Equine Thoracocentesis=
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==Equine Thoracocentesis==
 
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===Introduction===
==Introduction==
   
Thoracocentesis is a valuable '''diagnostic''' and '''therapeutic''' procedure.  
 
Thoracocentesis is a valuable '''diagnostic''' and '''therapeutic''' procedure.  
    
When the findings of thoracic auscultation or percussion are suggestive of pleural effusion, thoracocentesis can be performed to:
 
When the findings of thoracic auscultation or percussion are suggestive of pleural effusion, thoracocentesis can be performed to:
   
* '''Confirm''' the '''presence''' of pleural effusion
 
* '''Confirm''' the '''presence''' of pleural effusion
 
* Provide a '''specimen''' for '''examination''' which provide a diagnosis or guide the therapeutic plan
 
* Provide a '''specimen''' for '''examination''' which provide a diagnosis or guide the therapeutic plan
 
* '''Therapeautically drain''' a large volume of pleural fluid
 
* '''Therapeautically drain''' a large volume of pleural fluid
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The horse may show more discomfort if a significant amount of fluid is drained because the fluid had previously provided a 'cushion' effect in the pleural cavity. However the removal of this fluid is beneficial as it '''relieves dyspnoe'''a and '''removes infectious material''' from the pleural space, which aids resolution. The placement of '''chest drains''' following thoracocentesis may be necessary in cases of thoracic neoplasia and severe pleural effusion.
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The horse may show more discomfort if a significant amount of fluid is drained because the fluid had previously provided a 'cushion' effect in the pleural cavity. However the removal of this fluid is beneficial as it '''relieves dyspnoea''' and '''removes infectious material''' from the pleural space, which aids resolution. The placement of '''chest drains''' following thoracocentesis may be necessary in cases of thoracic neoplasia and severe pleural effusion.
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==Equipment==
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===Equipment===
 
* Sedation as necessary
 
* Sedation as necessary
 
* Clippers and materials to perform a surgical scrub
 
* Clippers and materials to perform a surgical scrub
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* EDTA tube, plain tube and sterile vial for culture
 
* EDTA tube, plain tube and sterile vial for culture
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==Procedure==
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===Procedure===
 
The site for thoracocentesis can be identified using anatomical landmarks; '''7-8th intercostal space''' on the '''left''' or '''6-7th intercostal space''' on the '''right''' '''midway between the shoulder and the elbow'''. For more reliable identification of the correct position for thoracocentesis '''ultrasound''' can be used. As there are vessels and nerves running along the caudal aspect of each rib, the cannula should aim for the '''cranial border of the rib''' in order to avoid damage to these structures.
 
The site for thoracocentesis can be identified using anatomical landmarks; '''7-8th intercostal space''' on the '''left''' or '''6-7th intercostal space''' on the '''right''' '''midway between the shoulder and the elbow'''. For more reliable identification of the correct position for thoracocentesis '''ultrasound''' can be used. As there are vessels and nerves running along the caudal aspect of each rib, the cannula should aim for the '''cranial border of the rib''' in order to avoid damage to these structures.
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* The horse should be sedated and the area clipped and scrubbed
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The horse should be '''sedated''' and the area clipped and '''scrubbed'''. '''[[Local Anaesthetics|Local anaesthetic]]''' should be administered into the subcutis, intercostal musculature and parietal pleura using a 23 gauge, 3 cm needle. A '''stab incision''' using a number 15 scalpel blade should be made through the skin. Prior to inserting the cannula, a '''three-way tap''' and extension set should be attached to it. Using moderate pressure, the cannula should be pushed through first the intercostal muscles and secondly through the parietal pleura in order to enter the thoracic cavity. Passage of the cannula through the parietal pleura is extremely painful to the horse if the area has not been fully desensitised by the local anaesthetic. A release in pressure should be felt when the cannula enters the thoracic cavity. The cannula can be manipulated and moved to collect as much fluid as possible.
 
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* Local anaesthetic should be administered into the subcutis, intercostal musculature and parietal pleura using a 23 gauge, 3 cm needle
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* A stab incision using a number 15 scalpel blade should be made through the skin
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* Prior to inserting the cannula, a three-way tap and extension set should be attached to it
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* Using moderate pressure, the cannula should be pushed through first the intercostal muscles and secondly through the parietal pleura in order to enter the thoracic cavity. Passage of the cannula through the parietal pleura is extremely painful to the horse if the area has not been fully desensitised by the local anaesthetic
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===Complications===
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Iatrogenic '''[[pneumothorax]]'''
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* A release in pressure should be felt when the cannula enters the thoracic cavity. The cannula can be manipulated and moved to collect as much fluid as possible
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===Pleural Fluid Analysis===
 
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==Complications==
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Iatrogenic '''pneumothorax'''
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==Peritoneal Fluid Analysis==
   
Analysis of the pleural fluid may in turn help you to determine the underlying disease process and develop a therapeutic plan.  
 
Analysis of the pleural fluid may in turn help you to determine the underlying disease process and develop a therapeutic plan.  
    
Pleural fluid in healthy horses normally contains '''less than 5,000 nucleated cells/l''' and '''less than 25g/l total protein'''. Levels greater than 10,000 nucleated cells/l and 35g/l total protein should be considered abnormal.
 
Pleural fluid in healthy horses normally contains '''less than 5,000 nucleated cells/l''' and '''less than 25g/l total protein'''. Levels greater than 10,000 nucleated cells/l and 35g/l total protein should be considered abnormal.
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=Small Animal Thoracocentesis=
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==Small Animal Thoracocentesis==
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==Introduction==
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===Introduction===
 
Thoracocentesis is a procedure which has both diagnostic and therapeutic value.  
 
Thoracocentesis is a procedure which has both diagnostic and therapeutic value.  
    
When the '''clinical history''', '''presenting signs''', '''thoracic auscultation''' and '''percussion''' of the animal suggest a pleural effusion, thoracocentesis can both '''confirm''' its presence and provide a '''specimen''' for '''examination'''. Ideally '''radiography''' (minimum of two views - lateral and dorsoventral) or '''ultrasound''' should be performed to confirm pleural space disease prior to thoracocentesis. However it can be particularly useful in the emergency patient (the dyspnoeic cat in particular) who is too unstable to undergo radiography or similar diagnostic tests as drainage of pleural fluid will both provide a preliminary diagnosis and improve clinical signs.
 
When the '''clinical history''', '''presenting signs''', '''thoracic auscultation''' and '''percussion''' of the animal suggest a pleural effusion, thoracocentesis can both '''confirm''' its presence and provide a '''specimen''' for '''examination'''. Ideally '''radiography''' (minimum of two views - lateral and dorsoventral) or '''ultrasound''' should be performed to confirm pleural space disease prior to thoracocentesis. However it can be particularly useful in the emergency patient (the dyspnoeic cat in particular) who is too unstable to undergo radiography or similar diagnostic tests as drainage of pleural fluid will both provide a preliminary diagnosis and improve clinical signs.
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==Equipment==
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===Equipment===
 
* Clippers and materials to perform a surgical scrub
 
* Clippers and materials to perform a surgical scrub
 
* Ultrasonography if available
 
* Ultrasonography if available
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The site for thoracocentesis is between the '''7th and 8th intercostal space'''. If fluid is suspected in the pleural space then the needle should be inserted '''2/3rds of the way down the chest'''. If '''pneumothorax''' is suspected then the needle should be inserted more '''dorsally''', approximately '''1/3rd of the way down the chest'''. Local anaesthetic can be used if necessary.
 
The site for thoracocentesis is between the '''7th and 8th intercostal space'''. If fluid is suspected in the pleural space then the needle should be inserted '''2/3rds of the way down the chest'''. If '''pneumothorax''' is suspected then the needle should be inserted more '''dorsally''', approximately '''1/3rd of the way down the chest'''. Local anaesthetic can be used if necessary.
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* Clip and scrub a generous area around the 7-8th rib space on both sides of the chest.  
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Clip and scrub a generous area around the '''7-8th rib space''' on both sides of the chest. Advance the needle slowly at a '''45 degree angle''' in the middle of the 7th or 8th intercostal space into the pleural space. A small amount of '''negative pressure''' should be applied as the needle passes through the thoracic wall. The needle should be angled downward, '''parallel to the body wall'''. The fluid or air should then be aspirated. The needle may need redirecting to access pockets of fluid.
 
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* Advance the needle slowly at a 45 degree angle in the middle of the 7th or 8th intercostal space into the pleural space.
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* A small amount of negative pressure should be applied as the needle passes through the thoracic wall.
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* The needle should be angled downward, parallel to the body wall.  
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* The fluid or air should then be aspirated. The needle may need redirecting to access pockets of fluid.
      
Up to 100mls of fluid per side can be expected in the cat. '''Removal of fluid should see an improvement in clinical signs'''.
 
Up to 100mls of fluid per side can be expected in the cat. '''Removal of fluid should see an improvement in clinical signs'''.
    
==Complications==
 
==Complications==
Iatrogenic pneumothorax
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Iatrogenic [[pneumothorax]]
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==Peritoneal Fluid Analysis==
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==Pleural Fluid Analysis==
 
Analysis of the pleural fluid may in turn help you to determine the underlying disease process and develop a therapeutic plan.
 
Analysis of the pleural fluid may in turn help you to determine the underlying disease process and develop a therapeutic plan.
 
The following can be analysed: '''cytology, total cell count, differential cell count, total protein, bacterial culture ans sensitivity, gram stain and triglyceride and cholesterol levels''' (if [[Chylothorax|chylothorax]] is suspected).  
 
The following can be analysed: '''cytology, total cell count, differential cell count, total protein, bacterial culture ans sensitivity, gram stain and triglyceride and cholesterol levels''' (if [[Chylothorax|chylothorax]] is suspected).  
    
The types of fluid that may cause pleural space disease are:  
 
The types of fluid that may cause pleural space disease are:  
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#[[Exudate]]
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#[[Modified Transudate]]
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#[[Transudate]]
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#[[Chylous Effusion|Chyle]]
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(1) [[Exudate]]
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These can be identified by the protein and cellular content of the sample.
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(2) [[Modified Transudate]]
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The fluid can give an indication of '''prognosis'''; in the cat prognosis is generally poor for all diagnoses except [[Pyothorax|pyothorax]] (an exudate with degenerate [[neutrophils]] and intracellular bacteria). Therefore it is often useful to perform in-house cytology to give a preliminary diagnosis, which allows the owners to make an informed decision before proceeding with further treatment. Differential diagnosis in the cat include [[Heart Failure|congestive heart failure]], [[Feline Infectious Peritonitis|FIP]], [[Pyothorax|pyothorax]], [[Neoplasia - Pathology|neoplasia]], [[Haemothorax|haemothorax]] and [[Chylothorax|chylothorax]]. ''It should be noted that any pleural effusion may produce bizarre [[mesothelial cells]] which could be mistaken for neoplastic cells.''
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(3) [[Transudate]]
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{{Learning
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|flashcards = [[Equine Internal Medicine Q&A 18]]
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}}
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(4) [[Chylous Effusion|Chyle]]
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==References==
 
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These can be identified by the protein and cellular content of the sample.
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The fluid fluid can give an indication of '''prognosis'''; in the cat prognosis is generally poor for all diagnosis except [[Pyothorax|pyothorax]] (an exudate with degenerate neutrophils and intracellular bacteria). Therefore it is often useful to perform in-house cytology to give a preliminary diagnosis, which allows the owners to make an informed decision before proceeding with further treatment. Differential diagnosis in the cat include [[Heart Failure|congestive heart failure]], [[Feline Infectious Peritonitis|FIP]], [[Pyothorax|pyothorax]], [[Neoplasia - Pathology|neoplasia]], [[Haemothorax|haemothorax]] and [[Chylothorax|chylothorax]]. It should be noted that any pleural effusion may produce bizarre mesothelial cells which could be mistaken for neoplastic cells.
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=References=
   
Adamantos, S (2011) '''Feline Respiratory Emergencies''' RVC Emergency Medicine and Critical Care Elective, ''Royal Veterinary College''
 
Adamantos, S (2011) '''Feline Respiratory Emergencies''' RVC Emergency Medicine and Critical Care Elective, ''Royal Veterinary College''
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RVC staff (2009) '''Respiratory System''' RVC Intergrated BVetMed Course, ''Royal Veterinary College''
 
RVC staff (2009) '''Respiratory System''' RVC Intergrated BVetMed Course, ''Royal Veterinary College''
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Rutgers, C H (1989) '''Thoracocentisis in the dog and cat''' ''In Practice 1989 11: 14-1''
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Rutgers, C H (1989) '''Thoracocentisis in the dog and cat''' ''In Practice'' 1989 11: 14-1
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Copas, V (2011) '''Diagnosis and treatment of equine pleuropneumonia''' ''In Practice 2011;33:155-162''
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Copas, V (2011) '''Diagnosis and treatment of equine pleuropneumonia''' ''In Practice'' 2011;33:155-162
    
RVC staff (2011) '''A logical approach to clinical problem solving''' RVC Feline Medicine Elective, ''Royal Veterinary College''   
 
RVC staff (2011) '''A logical approach to clinical problem solving''' RVC Feline Medicine Elective, ''Royal Veterinary College''   
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[[Category:To Do - Siobhan Brade]]
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[[Category:To Do - Manson review]]
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{{review}}
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[[Category:Clinical Techniques]]
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[[Category:Expert Review]]
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