Research topic: Signs and symptoms of ‘Pneumothorax’ and ‘Tension Pneumothorax’.
1) Pneumothorax: Symptoms and Signs include - Sudden chest pain (made worse by a deep breath or cough) Shortness of breath - Chest tightness - Rapid heart rate - Rapid breathing - Cough - Fatigue - Nasal flaring - Anxiety, stress and tension - Hypotension
•2) Tension Pneumothorax: Presenting Signs and Symptoms – Early findings Chest pain Dyspnea Anxiety Tachypnea (Abnormally fast breathing) Tachycardia Hyperresonance (exaggerated resonance on percussion) of the chest wall on the affected side Diminished breath sounds on the affected side
Late findings Decreased level of consciousness Tracheal deviation toward the contralateral (opposite side) side Hypotension Distension of neck veins (may not be present if hypotension is severe) Cyanosis (refers to the bluish coloration of the skin due to the presence of deoxygenated hemoglobin in blood vessels near the skin surface)
Chest X-Ray: Normally taken as an P-A view at maximum inspiration, although an A-P view may be taken in an emergency. A lateral view may be taken to localize any pathology. In a general chest X-ray we would look at: - The shape and bony structure of the chest wall - Whether the trachea is central - Whether the diaphragm is elevated or flat - The shape, size and position of the heart - The shape and size of the hilar shadows - The size and shape of any lung abnormalities and vascular shadowing
When there is a collapsed lung, the lobes will collapse in a characteristic direction. The inferior lobes will collapse inferiorly and medially. The left superior lobe collapses anteriorly, whilst the right superior lobe collapses superio-laterally, forming the appearance of an arch over the remaining lobes. The right middle lobe collapses anterior and medially, obscuring the right cardiac border. In the case of an entire lung collapse, the whole mediastinum will shift towards the side of the collapse. However if there is fluid in the pleural cavity this will push the mediastinum in the opposite direction.
For a pneumothorax air can be seen within the pleural cavity and in a supine chest X-ray the deep sulcus sign can be seen, that is that the place where the ribs and the diaphragm meet appears lower on the affected side.
For a Haemothorax, an erect X-ray will show a fluid level with a meniscus. It takes roughly 400-500 mls of blood to obliterate the costophrenic angle on an X-ray. On a supine X-ray no fluid level is visible (the blood moves to the posterior of the chest), and shows only diffuse opacification of the haemothorax, through which the lung can be seen.
Medical Sonography: Uses ultrasound waves to penetrate tissue, and uses the speed at which they return to build a cross-sectional picture of that tissue. In a haemothorax this can be used to detect small amounts of blood that does not show up on X-ray, however a pneumothorax may make this technique inaccurate. For Pneumothorax alone an ultrasound is effective for use on a supine patient, where chest X-rays are often ambiguous. Certain features (lung sliding, comet tail artefacts) are absent in a pneumothorax ultrasound, allowing for quick diagnosis in emergency situations.
Computed Tomography: CT scanners use a collimated beam of X-rays that are fired at a slice of tissue. The differences in intensity and scattering of the X-rays are used to generate a cross-sectional picture, identifying different tissues by their densities. CT provides a more sensitive technique to detect blood in the pleural space then a chest X-ray, and may be helpful in differentiating a haemothorax from other thoracic pathologies such as pulmonary contusion or aspiration. For a pneumothorax CT can be used to determine the exact size of the pneumothorax, and possibly reveal any underlying causes. For pneumothorax CT is not thought to be any more sensitive then X-ray.
Arterial Blood Gases: Measures the levels of oxygen and carbon dioxide in the blood to determine how well your lungs are working. A sample of blood is taken from inside the wrist (may be taken from the groin or just above the elbow crease). Gives: - Partial Pressure of Oxygen: Shows how well the lungs are exchanging oxygen with the blood. Normal range is 70-100 mmHg. Abnormal results may indicate hyperventilation (high), lung diseases such as COPD (low), certain heart disorders (low), pulmonary edema (low) or pulmonary embolism (low). - Partial Pressure of Carbon dioxide: Shows how well the lungs are exchanging CO2 with the blood. Normal range is 35-40 mmHg. Abnormally low levels may indicate hyperventilation, PE or pregnancy. Abnormally high levels may indicate a COPD, severe head injury, hypoventilation or disturbed sleep. Sedatives and narcotics can also raise CO2 levels. - Blood pH: Can show respiratory or metabolic problems. Normal range is 7.35-7.44. A low pH with high CO2 shows respiratory acidosis and can indicate conditions in which CO2 cannot be exhaled such as asthma, COPD, pneumonia, cherst injury, drug OD. A high pH with low CO2 is called respiratory alkalosis and can result from hyperventilation, heart failure, anaemia, CO poisoning, PE or shock. - Bicarbonate: The most important pH buffer in the blood. Normal levels are 21-28 mEq/L. High levels can be indicative of respiratory acidosis, or can be caused by persistent vomiting, blood transfusions. Low levels can indicate respiratory alkalosis. - Oxygen Saturation: Like PPO2 can show lung function in exchanging oxygen. Normal levels are 95-100%. Low saturation levels may indicate low levels of oxygen in the air, COPD, pneumonia, certain heart disorders, PE, or hypoventilation.
Definition Pneumothorax is a collapsed lung caused by accumulation of air or gases in the pleural cavity. It may occur spontaneously or as a result of trauma to the chest. Pneumothoraces can be divided into tension and non-tension pneumothoraces.
In a tension pneumothorax, the air accumulates in pleural cavity with each breath. This increases intrathoracic pressure and results in shifts of the mediastinum away from the affected lung.
Causes Causes of pneumothorax include: - Trauma to the chest - Spontaneously (most commonly in tall and thin young males) - The rupture of the pleural bleb (an imperfection in the lining of the lung). This is thought to be due to congenital defects in the connective tissue of the alveolar walls. In this case, both lungs are affected. - In patients >40 years, usual cause is underlying chronic obstructive pulmonary disease (COPD). E.g. Emphysema Rarer causes include: - Chronic lung infections and destructive lung disease. E.g. o Bronchial asthma o Tuberculosis o Pneumonia o Lung cancer - Lung abscess breaking down and leading to bronchopleural fistula - Severe pulmonary fibrosis with cyst formation
References Clinical Medicine by Kumar and Clark http://www.medic8.com/healthguide/articles/pneumothorax.html
Deaths reportable to the coroner: When a death is reported, the coroner, who is usually a magistrate, is required to find out:
-the identity of the deceased -how death occurred (the circumstances) -the cause of death -the particulars needed to register the death
Under the Coroner's Act of 1985, reportable deaths are onces which: -appear to have been unexpected, unnatural, violent or to have resulted directly or indirectly from accident or injury
-occur during an anaesthetic
-occur as a result of an anaesthetic and is not due to natural causes;
-were of a person who immediately before death was a person held in care (such as prison, police cell, mental health service or foster care)
-were of a person whose identity is unknown
-have occurred and a ‘death certificate’ has not been signed
When a death is reportable to the coroner, it is an offence for a doctor to complete a death certificate.
Initial Treatment: - normal First Aid (DR ABC) to keep the patient alive - Control/remove any obvious causes of shock (eg. Bleeding, allergen) if possible - Rest patient with legs elevated, and in position of least pain - Maintain patient’s body temperature (but do not overheat)
In-Hospital Treatment: The major goal of treatment is to return O2 delivery to normal. This is mainly done by increasing cardiac output or blood pressure, but increasing the O2 content of the blood can also help.
Hypovolaemic Shock: Return blood volume to normal – IV saline - blood transfusion if more than 20% of blood volume has been lost
Cardiogenic Shock: - Improve myocardial function - Positive inotropes are used to increase contractility - If there is a decrease in coronary artery perfusion, a vasoconstrictor may also be given to increase diastolic pressure (as the coronary arteries fill during diastole. However, this needs to be carefully monitored.
Vascular (Distributive) Shock: - Vasodilation causes fluid leaking from capillaries, so maintain fluid levels as for hypovolaemic shock. - Inotropes or vasoconstrictors may be necessary to increase blood pressure
Anaphylactic Shock: - Remove allergen - Subcutaneous injection of adrenaline can help to reverse effects. - Make sure to maintain airway (intubation may be necessary)
Septic shock: - Antagonise bacterial vasodilators with vasoconstrictors and positive inotropes
Obstructive Shock: - Obstruction must be removed (eg. Surgery, thrombolytic drugs)
Shane
References: Close, Alan (2004). Emergency Care, 6th Ed
Joynt, Gavin (April 2003). Introduction to management of shock for junior ICU trainees and medical students. The Chinese University of Hong Kong. http://www.aic.cuhk.edu.hk/web8/shock.htm
JESS said... Hi guys, sorry about the formatting, it went wierd when I coppied from word.
Superficial anatomy of the thorax
There are many bony landmarks of the chest which can be seen and/or palpated • Clavicles • Sternum – lies in the anterior median line • Jugular notch • Manubrium • Sternal angle – lies at level of T4/5 vertebrae and marks the second rib *The T4/5 line is also significant because it is at this level that all the major vessels and components of the thorax lie: o Arch of the aorta o Arch of the azygos vein o Superior vena cava (passes inferiorly deep to the manubrium and sternal angle – slightly to right side) • Intermammary cleft (cleavage between female breasts) • Xiphoid process – lies in slight depression and can be palpated • Ribs/intercostal spaces – can be seen or palpated (if fat is minimal) o SVC enters right atrium of heart opposite right 3rd intercostal cartilage
Longitudinal lines can also be used to navigate the thorax: • Anterior median (midsternal line): • Midclavicular line • Anterior axillary line • Midaxillary line • Posterior axillary line • Posterior median (midvertebral) line • Scapular line
Deep anatomy of the thorax
The thorax includes the heart, lungs and major vessels. • Lungs: o occupy most of the thoracic cavity o apex begins above level of clavicles o lungs are covered in two layers of pleura: visceral and parietal with pleural fluid in-between the two layers. o Space occupied by parietal pleura is greater than lungs during quiet respiration. This is of clinical significance because it is at these points that pleura is at risk. Injury to the pleura can result in pneumothorax. • Mediastinum: o Occupies the space between the pulmonary cavities o Is divided into superior, anterior, middle and posterior mediastinum o superior: includes – superior vena cava, arch of aorta, trachea, thymus (becomes less prominent with age), and associated nerves and vessels. o Middle: includes – heart, pericardium, ascending aorta, lower half of superior vena cava, burification of the trachea and the two bronchi, the pulmonary artery and veins, phrenic nerves and some lymphatic glands o Anterior mediastinum: includes – some loose areolar tissue, lymph vessels and glands, some small branches of the internal mammary artery o Posterior mediastinum: includes – thoracic aorta, azygos vein, vagus nerve, esophogus, thoracic duct
Structures that could have been damaged by 15cm knife wound to right chest: • Pretty much anything!!
Structures that could have been damaged by chest tube being inserted into 6th intercostal space (instead of 5th) • Diaphragm • Liver • Artery?
The different types of shock are characterized by the same clinical signs.
a)Hypotension: Usually defined as a systolic blood pressure of 90mmHg or less but must be compared to the patient's normal blood pressure. While a 90mmHg systolic BP might be normal in a healthy athletic adult, a pressure of 100mmHg may indicate shock in a patient who is normally hypertensive.A drop in systolic pressure of more than 10-20mmHg and increase in pulse of more than 15 with positional change suggests depleted intravascular volume.Orthostatic hypotension resulting from peripheral neuropathy or use of beta blockers is usually not associated with an increase in pulse rate.
b)End-Organ Hypoperfusion: Patients in shock often have cool or mottled extremities (clammy) and weak or absent peripheral pulses.Splanchnic vasoconstriction leads to oliguria,bowel ischemia and hepatic dysfunction which can result in multiorgan failure.
c)Altered Mental Status: Patients may demonstrate normal mental status or may be restless,agitated, confused, lethargic or comatose as a result of inadequate perfusion of the brain.
A small pneumohorax is deflation of a small part of the lung only (less than 20%). It has few symptoms and generally resolves slowly by itself.
any more than 20% deflation is dangerous, will cause a lot more distress and requires more urgent treatment that has 3 stages (good simple diagram in Kumar and Clark):
1) Simple aspiration
- Local anaesthetic - 3-4 cm cannula into the 2nd intercostal space, mid clavicular line. (watch out for intercostal vessels : ) - Air can then be sucked out using a syringe.
If aspiration doesn't work, ie. the lung deflates again...(I think this is because the hole in the lung is large and continues to leak air. I'm not sure though)
the next stage is an intercostal drainage tube
2. Insert an intercostal drainage tube with an underwater seal for 2-3 days(sucks out air or blood and stops unwanted particles going back into the chest, possibly it also gives time for the lung to regenerate or close off the damaged area): There are a few safe spots for this (netter's)
- 2nd or 3rd intercostal space at the mid clavicular line for pneumothorax.
- 5th intercostal space at the mid axillary line for hemothorax.
If the lungs expand and the tube doesn't bubble its all good to be taken out.
If the pneumothorax still doesn't resolve and the tube bubbles (indicates that air is still infiltrating the chest) the next stage in treatment is surgery ( Kumar and Clark)
3. Pleurectomy or pleurodesis - these surgeries involve either removing pleural layers or introducing chemicals to help them stick. This prevents the lung from falling away from the chest wall.
Hope this all makes sense ( it still confuses me a bit)
10 comments:
Research topic: Signs and symptoms of ‘Pneumothorax’ and ‘Tension Pneumothorax’.
1) Pneumothorax: Symptoms and Signs include - Sudden chest pain (made worse by a deep breath or cough)
Shortness of breath
- Chest tightness
- Rapid heart rate
- Rapid breathing
- Cough
- Fatigue
- Nasal flaring
- Anxiety, stress and tension
- Hypotension
•2) Tension Pneumothorax: Presenting Signs and Symptoms –
Early findings
Chest pain
Dyspnea
Anxiety
Tachypnea (Abnormally fast breathing)
Tachycardia
Hyperresonance (exaggerated resonance on percussion) of the chest wall on the affected side
Diminished breath sounds on the affected side
Late findings
Decreased level of consciousness
Tracheal deviation toward the contralateral (opposite side) side
Hypotension
Distension of neck veins (may not be present if hypotension is severe)
Cyanosis (refers to the bluish coloration of the skin due to the presence of deoxygenated hemoglobin in blood vessels near the skin surface)
References:
•http://www.emedicine.com/med/topic2793.htm
•http://www.nlm.nih.gov/medlineplus/ency/article/000090.htm#Symptoms
•http://www.medicinenet.com/pneumothorax/index.htm
•http://health.allrefer.com/health/pneumothorax-symptoms.html
SHOCK
>>Circulatory failure resulting in inadequate organ perfusion.(Generally correlates to a systolic blood pressure <90mmHg.)
(Different categories of shock – summary; possible causes)
1)Hypovolaemic - Low blood volume; trauma, ruptured aortic aneurysm, diarrhoea, burns, dehydration.
2)Anaphylactic - Large-scale vasodilatation; histamine release due to IgE-mediated hypersensitivity reaction to drugs, particular foods, etc.
3)Neurogenic – Autonomic Nervous System fails to regulate blood pressure (loss of sympathetic input to smooth muscle in vessel walls); damage to CNS, e.g. post-spinal surgery.
4)Septic – Vasodilatation; Bacterial endotoxins.
5)Cardiogenic – Failure of heart to maintain circulation; arrhythmias, tension pnuemothorax, myocardial infarction, myocarditis, pulmonary embolus, aortic dissection, cardiac tamponade.
References:
- Week 2 Med2031 Lecture Notes
- Oxford Handbook of Clinical Medicine 6th Edition, Longmore et. al.
See you all friday! :o)
Robb says…
Investigations:
Chest X-Ray: Normally taken as an P-A view at maximum inspiration, although an A-P view may be taken in an emergency. A lateral view may be taken to localize any pathology. In a general chest X-ray we would look at:
- The shape and bony structure of the chest wall
- Whether the trachea is central
- Whether the diaphragm is elevated or flat
- The shape, size and position of the heart
- The shape and size of the hilar shadows
- The size and shape of any lung abnormalities and vascular shadowing
When there is a collapsed lung, the lobes will collapse in a characteristic direction. The inferior lobes will collapse inferiorly and medially. The left superior lobe collapses anteriorly, whilst the right superior lobe collapses superio-laterally, forming the appearance of an arch over the remaining lobes. The right middle lobe collapses anterior and medially, obscuring the right cardiac border. In the case of an entire lung collapse, the whole mediastinum will shift towards the side of the collapse. However if there is fluid in the pleural cavity this will push the mediastinum in the opposite direction.
For a pneumothorax air can be seen within the pleural cavity and in a supine chest X-ray the deep sulcus sign can be seen, that is that the place where the ribs and the diaphragm meet appears lower on the affected side.
For a Haemothorax, an erect X-ray will show a fluid level with a meniscus. It takes roughly 400-500 mls of blood to obliterate the costophrenic angle on an X-ray. On a supine X-ray no fluid level is visible (the blood moves to the posterior of the chest), and shows only diffuse opacification of the haemothorax, through which the lung can be seen.
Medical Sonography: Uses ultrasound waves to penetrate tissue, and uses the speed at which they return to build a cross-sectional picture of that tissue. In a haemothorax this can be used to detect small amounts of blood that does not show up on X-ray, however a pneumothorax may make this technique inaccurate. For Pneumothorax alone an ultrasound is effective for use on a supine patient, where chest X-rays are often ambiguous. Certain features (lung sliding, comet tail artefacts) are absent in a pneumothorax ultrasound, allowing for quick diagnosis in emergency situations.
Computed Tomography: CT scanners use a collimated beam of X-rays that are fired at a slice of tissue. The differences in intensity and scattering of the X-rays are used to generate a cross-sectional picture, identifying different tissues by their densities. CT provides a more sensitive technique to detect blood in the pleural space then a chest X-ray, and may be helpful in differentiating a haemothorax from other thoracic pathologies such as pulmonary contusion or aspiration. For a pneumothorax CT can be used to determine the exact size of the pneumothorax, and possibly reveal any underlying causes. For pneumothorax CT is not thought to be any more sensitive then X-ray.
Arterial Blood Gases: Measures the levels of oxygen and carbon dioxide in the blood to determine how well your lungs are working. A sample of blood is taken from inside the wrist (may be taken from the groin or just above the elbow crease). Gives:
- Partial Pressure of Oxygen: Shows how well the lungs are exchanging oxygen with the blood. Normal range is 70-100 mmHg. Abnormal results may indicate hyperventilation (high), lung diseases such as COPD (low), certain heart disorders (low), pulmonary edema (low) or pulmonary embolism (low).
- Partial Pressure of Carbon dioxide: Shows how well the lungs are exchanging CO2 with the blood. Normal range is 35-40 mmHg. Abnormally low levels may indicate hyperventilation, PE or pregnancy. Abnormally high levels may indicate a COPD, severe head injury, hypoventilation or disturbed sleep. Sedatives and narcotics can also raise CO2 levels.
- Blood pH: Can show respiratory or metabolic problems. Normal range is 7.35-7.44. A low pH with high CO2 shows respiratory acidosis and can indicate conditions in which CO2 cannot be exhaled such as asthma, COPD, pneumonia, cherst injury, drug OD. A high pH with low CO2 is called respiratory alkalosis and can result from hyperventilation, heart failure, anaemia, CO poisoning, PE or shock.
- Bicarbonate: The most important pH buffer in the blood. Normal levels are 21-28 mEq/L. High levels can be indicative of respiratory acidosis, or can be caused by persistent vomiting, blood transfusions. Low levels can indicate respiratory alkalosis.
- Oxygen Saturation: Like PPO2 can show lung function in exchanging oxygen. Normal levels are 95-100%. Low saturation levels may indicate low levels of oxygen in the air, COPD, pneumonia, certain heart disorders, PE, or hypoventilation.
References:
Kumar, Clarke, Clinical Medicine, Elsevier Saunders, Sixth edition, 2005
Definition
Pneumothorax is a collapsed lung caused by accumulation of air or gases in the pleural cavity. It may occur spontaneously or as a result of trauma to the chest. Pneumothoraces can be divided into tension and non-tension pneumothoraces.
In a tension pneumothorax, the air accumulates in pleural cavity with each breath. This increases intrathoracic pressure and results in shifts of the mediastinum away from the affected lung.
Causes
Causes of pneumothorax include:
- Trauma to the chest
- Spontaneously (most commonly in tall and thin young males)
- The rupture of the pleural bleb (an imperfection in the lining of the lung). This is thought to be due to congenital defects in the connective tissue of the alveolar walls. In this case, both lungs are affected.
- In patients >40 years, usual cause is underlying chronic obstructive pulmonary disease (COPD). E.g. Emphysema
Rarer causes include:
- Chronic lung infections and destructive lung disease. E.g.
o Bronchial asthma
o Tuberculosis
o Pneumonia
o Lung cancer
- Lung abscess breaking down and leading to bronchopleural fistula
- Severe pulmonary fibrosis with cyst formation
References
Clinical Medicine by Kumar and Clark
http://www.medic8.com/healthguide/articles/pneumothorax.html
Deaths reportable to the coroner:
When a death is reported, the coroner, who is usually a magistrate, is required to find out:
-the identity of the deceased
-how death occurred (the circumstances)
-the cause of death
-the particulars needed to register the death
Under the Coroner's Act of 1985, reportable deaths are onces which:
-appear to have been unexpected, unnatural, violent or to have resulted directly or indirectly from accident or injury
-occur during an anaesthetic
-occur as a result of an anaesthetic and is not due to natural causes;
-were of a person who immediately before death was a person held in care (such as prison, police cell, mental health service or foster care)
-were of a person whose identity is unknown
-have occurred and a ‘death certificate’ has not been signed
When a death is reportable to the coroner, it is an offence for a doctor to complete a death certificate.
www.coronerscourt.vic.gov.au
www.medicalboardofvic.org.au
Treatment of Shock
Initial Treatment:
- normal First Aid (DR ABC) to keep the patient alive
- Control/remove any obvious causes of shock (eg. Bleeding, allergen) if possible
- Rest patient with legs elevated, and in position of least pain
- Maintain patient’s body temperature (but do not overheat)
In-Hospital Treatment:
The major goal of treatment is to return O2 delivery to normal. This is mainly done by increasing cardiac output or blood pressure, but increasing the O2 content of the blood can also help.
Hypovolaemic Shock:
Return blood volume to normal
– IV saline
- blood transfusion if more than 20% of blood volume has been lost
Cardiogenic Shock:
- Improve myocardial function
- Positive inotropes are used to increase contractility
- If there is a decrease in coronary artery perfusion, a vasoconstrictor may also be given to increase diastolic pressure (as the coronary arteries fill during diastole. However, this needs to be carefully monitored.
Vascular (Distributive) Shock:
- Vasodilation causes fluid leaking from capillaries, so maintain fluid levels as for hypovolaemic shock.
- Inotropes or vasoconstrictors may be necessary to increase blood pressure
Anaphylactic Shock:
- Remove allergen
- Subcutaneous injection of adrenaline can help to reverse effects.
- Make sure to maintain airway (intubation may be necessary)
Septic shock:
- Antagonise bacterial vasodilators with vasoconstrictors and positive inotropes
Obstructive Shock:
- Obstruction must be removed (eg. Surgery, thrombolytic drugs)
Shane
References:
Close, Alan (2004). Emergency Care, 6th Ed
Joynt, Gavin (April 2003). Introduction to management of shock for junior ICU trainees and medical students. The Chinese University of Hong Kong. http://www.aic.cuhk.edu.hk/web8/shock.htm
JESS said...
Hi guys, sorry about the formatting, it went wierd when I coppied from word.
Superficial anatomy of the thorax
There are many bony landmarks of the chest which can be seen and/or palpated
• Clavicles
• Sternum – lies in the anterior median line
• Jugular notch
• Manubrium
• Sternal angle – lies at level of T4/5 vertebrae and marks the second rib
*The T4/5 line is also significant because it is at this level that all the major vessels and components of the thorax lie:
o Arch of the aorta
o Arch of the azygos vein
o Superior vena cava (passes inferiorly deep to the manubrium and sternal angle – slightly to right side)
• Intermammary cleft (cleavage between female breasts)
• Xiphoid process – lies in slight depression and can be palpated
• Ribs/intercostal spaces – can be seen or palpated (if fat is minimal)
o SVC enters right atrium of heart opposite right 3rd intercostal cartilage
Longitudinal lines can also be used to navigate the thorax:
• Anterior median (midsternal line):
• Midclavicular line
• Anterior axillary line
• Midaxillary line
• Posterior axillary line
• Posterior median (midvertebral) line
• Scapular line
Deep anatomy of the thorax
The thorax includes the heart, lungs and major vessels.
• Lungs:
o occupy most of the thoracic cavity
o apex begins above level of clavicles
o lungs are covered in two layers of pleura: visceral and parietal with pleural fluid in-between the two layers.
o Space occupied by parietal pleura is greater than lungs during quiet respiration. This is of clinical significance because it is at these points that pleura is at risk. Injury to the pleura can result in pneumothorax.
• Mediastinum:
o Occupies the space between the pulmonary cavities
o Is divided into superior, anterior, middle and posterior mediastinum
o superior: includes – superior vena cava, arch of aorta, trachea, thymus (becomes less prominent with age), and associated nerves and vessels.
o Middle: includes – heart, pericardium, ascending aorta, lower half of superior vena cava, burification of the trachea and the two bronchi, the pulmonary artery and veins, phrenic nerves and some lymphatic glands
o Anterior mediastinum: includes – some loose areolar tissue, lymph vessels and glands, some small branches of the internal mammary artery
o Posterior mediastinum: includes – thoracic aorta, azygos vein, vagus nerve, esophogus, thoracic duct
Structures that could have been damaged by 15cm knife wound to right chest:
• Pretty much anything!!
Structures that could have been damaged by chest tube being inserted into 6th intercostal space (instead of 5th)
• Diaphragm
• Liver
• Artery?
Diagnosis of Shock (Signs & Symptoms)
The different types of shock are characterized by the same clinical signs.
a)Hypotension:
Usually defined as a systolic blood pressure of 90mmHg or less but must be compared to the patient's normal blood pressure. While a 90mmHg systolic BP might be normal in a healthy athletic adult, a pressure of 100mmHg may indicate shock in a patient who is normally hypertensive.A drop in systolic pressure of more than 10-20mmHg and increase in pulse of more than 15 with positional change suggests depleted intravascular volume.Orthostatic hypotension resulting from peripheral neuropathy or use of beta blockers is usually not associated with an increase in pulse rate.
b)End-Organ Hypoperfusion:
Patients in shock often have cool or mottled extremities (clammy) and weak or absent peripheral pulses.Splanchnic vasoconstriction leads to oliguria,bowel ischemia and hepatic dysfunction which can result in multiorgan failure.
c)Altered Mental Status:
Patients may demonstrate normal mental status or may be restless,agitated, confused, lethargic or comatose as a result of inadequate perfusion of the brain.
Reference:
Current Medical Diagnosis & Treatment 2004 Tierney et al.
Treatment of pneumothorax:
A small pneumohorax is deflation of a small part of the lung only (less than 20%). It has few symptoms and generally resolves slowly by itself.
any more than 20% deflation is dangerous, will cause a lot more distress and requires more urgent treatment that has 3 stages (good simple diagram in Kumar and Clark):
1) Simple aspiration
- Local anaesthetic
- 3-4 cm cannula into the 2nd intercostal space, mid clavicular line. (watch out for intercostal vessels : )
- Air can then be sucked out using a syringe.
If aspiration doesn't work, ie. the lung deflates again...(I think this is because the hole in the lung is large and continues to leak air. I'm not sure though)
the next stage is an intercostal drainage tube
2. Insert an intercostal drainage tube with an underwater seal for 2-3 days(sucks out air or blood and stops unwanted particles going back into the chest, possibly it also gives time for the lung to regenerate or close off the damaged area): There are a few safe spots for this (netter's)
- 2nd or 3rd intercostal space at the mid clavicular line for pneumothorax.
- 5th intercostal space at the mid axillary line for hemothorax.
If the lungs expand and the tube doesn't bubble its all good to be taken out.
If the pneumothorax still doesn't resolve and the tube bubbles (indicates that air is still infiltrating the chest) the next stage in treatment is surgery ( Kumar and Clark)
3. Pleurectomy or pleurodesis - these surgeries involve either removing pleural layers or introducing chemicals to help them stick. This prevents the lung from falling away from the chest wall.
Hope this all makes sense ( it still confuses me a bit)
Alex
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