PBL 1 Flashcards
What are 7 different types of Pneumothorax?
Primary Spontaneous Pneumothorax (PSP)
Secondary Spontaneous Pneumothorax (SSP)
Closed Pneumothorax
Open Pneumothorax
Traumatic Pneumothorax
Iatrogenic Pneumothorax
Tension Pneumothorax
What is Primary Spontaneous Pneumothorax, what are the symptoms and what are the 6 predisposing risk factors?
Primary Spontaneous Pneumothorax (PSP) tends to occur in young people without underlying lung problems and usually causes limited symptoms. Chest pain and mild breathlessness are the main symptoms. Risk factors:
Male 15-30, Smoking, Tall stature, Apical subpleural blebs, Atmospheric pressure changes, Exposure to loud music.
What is Secondary Spontaneous Pneumothorax (SSP?). When should you suspect it? Which patients is it most common in?
How does it compare to PSP?
SSP occurs by definition in those with underlying lung disease. The symptoms tend to be more severe, as the unaffected lung is less able to compensate for the affected side. The size of the pneumothorax bears little relationship to the symptoms.
Suspect it if you see sudden breathlessness in someone with underlying problem such as CF, COPD. Most common in older patients.
More severe symptoms and higher mortality rate than PSP.
Describe closed pneumothorax. How is it resolved? What problem is uncommon with closed pneumothorax?
Air leaks from the lungs into the pleural cavity. The pneumothorax is called closed if the opening between the lung and the pleural cavity seals off while the lung is deflating, and does not reopen. In this case, the pleural pressure stays negative and reabsorption of the air and reexpansion of the lungs will occur in a few days or weeks. Infection is uncommon.
Describe open pneumothorax. What are some conditions that cause this? (3)
In open pneumothorax, the opening between the lung and pleural cavity does not close, so the pressure in the pleural cavity is the same as atomspheric pressure. Air continues to move between the lung and pleural space.
Commonly seen after the rupture of an emphysematous bulla, tuberculous cavity or lung abcess into the pleural space.
What types of treatment may cause iatrogenic pneumothorax? (3)
1) intrathoracic surgery
2) thoracentesis (pleural tap to remove fluid or air)
3) placement of chest drain
What are some causes of tension pneumothorax? (3)
1) Traumatic injury
2) Chronic Lung Disease
3) result of a medical procedure (iatrogenic)
What is the mechanism of tension pneumothorax? What dangerous effects does this condition have?
If the hole between the airway and the pleura is small, the wound can act as a one way valve, so air enters the chest cavity but cannot escape. The intrapleural pressure may rise to well over atmospheric levels. This greatly increased pressure in the pleural space causes the lung to collapse completely, compresses the heart and pushes the heart and associated blood vessels towards the unaffected side. The impairment of systemic venous return causes cardiovascular compromise.
Which patients may have a tension pneumothorax which is difficult to spot?
Tension pneumothorax may occur in those receiving mechanical ventilation, in which case it may be difficult to spot as the person is typically sedated; it is often noted because of sudden deterioration.
Which signs of tension pneumothorax should you not rely on?
Deviation of the trachea (windpipe) to one side and the presence of raised jugular venous pressure (distended neck veins) are not reliable as clinical signs
What are three unusual causes of pneumothorax?
- Acupuncture (rarely)
- Scuba diving.
- Flying at high altitudes
What are the symptoms of spontaneous pneumothorax? (7)
- Pain: One sided, Dull, sharp, or stabbing, Sudden onset, becomes worse with deep breathing or coughing.
- Shortness of breath
- Rapid breathing
- Hypoxaemia (decreased blood oxygen) maybe cyanosis (blue lips)
- Abnormal breathing movement (that is, little chest wall movement when breathing)
- Cough
- Hypercapnia (accumulation of carbon dioxide in the blood) is sometimes encountered; this may cause confusion and coma.
In patient with a small pneumothorax the exam may be normal
How do you diagnose simple (non tension) pneumothorax?
The combination of absent breath sounds and resonant percussion note is diagnostic of pneumothorax
What are the three main stages of treatment for simple (non tension) pneumothorax?
1) do nothing: if the pneumothorax is small enough, it may resolve on its own, but most need treatment.
2) Re-expand the lung by removing air from the chest. This is done by inserting a needle and syringe (if the pneumothorax is small) or chest tube through the chest wall. The lung will then re-expand itself within a few days.
3) Surgery may be needed for repeat occurrences : Pleurectomy, pleural abrasion.
What are the two procedures you can do to drain air from the chest, and which patients do you do them on?
- Percutaneous needle aspiration of air: perform on young patients with a moderate or large spontaneous primary pneumothorax: a simple and well tolerated alternative to intercostal tube drainage with a 60-80% chance of avoiding the need for a chest drain.
- Intercostal Chest Tube: In patients with underlying chronic lung disease even a small secondary pneumothorax may cause respiratory failure; hence all such patients require intercostal tube drainage and inpatient observation.
How do you fit an intercostal chest drain? What do you look out for while the drain is in place?
Insert Intercostal drains into the 4th 5th or 6th intercostal space in the mid axilliary line. Advance tube in an apical direction. Use an underwater seal or one-way Heimlich valve. Secure the tube firmly to the chest wall.
Look for continued bubbling after 5-7 days: this is an indication for surgery. If bubbling in the underwater bottle stops prior to full reinflation, the tube is either blocked, kinked or displaced.
When do you remove a chest drain? What should you never do with a chest drain?
- The drain should be removed 24 hours after the lung has been fully reinflated and the bubbling stopped. Continued bubbling after 5-7 days is an indication for surgery.
- Clamping of the drain is potentially dangerous and is never indicated
What treatment do you always give spontaneous pneumothorax patients, even if you are draining them, and why?
All patients should receive supplemental oxygen as this accelerates the rate which air is reabsorbed into the pleura.
How do you control pain and discomfort in a pneumothorax patient? When is the patient allowed to resume daily activities, and what advice are they given?
- Pain: appropriate analgesics, but the use of respiratory depressants is avoided.
- The patient usually is more comfortable if allowed to sit up.
- As soon as the lung lesion heals and the lung is reexpanded, the patient can resume usual daily activities
- The patient is taught how to turn, cough, breathe deeply, and perform passive exercises and is told to avoid stretching, reaching, or making sudden movements.
- Advise not to smoke, drink fluids copiously, exercise, avoid fatigue and strenuous activity.
What is the risk of recurrrence of primary spontaneous pneumothorax?
After primary spontaneous pneumothorax, recurrence occurs within a year of either aspiration or tube drainage in approximately 25% of patients, and should prompt definitive treatment with surgery.
What is pleurodesis and what are the indications for it?
Surgical pleurodesis is recommended:
- in all patients following the recurrence of PSP
- following the first episode of SSP if low respiratory reserve makes recurrence hazardous.
- for patients who plan to continue activities where pneumothorax would be dangerous (Eg flying or diving) after the first episode of PSP
Pleurodesis can be achieved by plural abrasion or parietal pleurectomy
How is pleurodesis carried out?
Pleurodesis procedure: the pleural space is destroyed by the adhesion of the two pleurae.
Can be done chemically or surgically.
- Chemicals, usually a slurry of talc, are introduced into the pleural space through a chest drain. This causes irritation between the parietal and the visceral layers of the pleura causing them to stick together.
- Surgical pleurodesis involves mechanically irritating the parietal pleura, often with a rough pad.
- Surgical removal of parietal pleura is an effective way of achieving stable pleurodesis.
What are the causes of tension pneumothorax? (3)
- Trauma: a penetrating chest wound allows outside air to enter the chest, causing the lung to collapse. Air cannot escape from chest cavity because the wound becomes a one way valve.
- Hidden injury, such as a fractured rib, that punctures the lung.
- Lung conditions
What are the common (5) and more unusual symptoms (10) of tension pneumothorax?
Common Symptoms:
Severe sudden Chest pain, Respiratory distress, Tachycardia, Rapid breathing, Marked anxiety.
Less Frequent Symptoms:
Distended neck veins, Hypoxaemia maybe cyanosis, Weak pulse, Decreased breath sounds on the affected side, Shift of the mediastinum to the opposite side, Hypotension, Diaphoresis (excessive sweating), Elevated temperature, Pallor, Dizziness
How do you distinguish between pneumothorax on an Xray and emphysematous bullae?
Care must be taken to differentiate betwee a large pre-existing emphysematous bulla (single or multiple large alveolar cysts seen in emphysema) and and a pneumothorax to avoid misdirected attempts at aspiration. Where doubt exists, CT is useful for distinguishing bullae from pleural air.
Why is tension pneumothorax so dangerous?
Tension pneumothorax can cause death rapidly due to inadequate heart output or insufficient blood oxygen (hypoxemia), and must be treated as a medical emergency.
What is the autonomic nervous system ANSI what does it control?
What is it part of?
What is it in contrast to?
What does it control? (8 examples)
The autonomic nervous system (ANS or visceral nervous system) is the part of the peripheral nervous system PNS.
It acts as a control system functioning largely un-consciously, and controls visceral functions.
It stands in contrast to the somatic nervous system, (SNS) which exerts conscious control over skeletal muscles.
The ANS affects heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils, micturition (urination), and sexual arousal.
What type of nervous divisions are the SNS and the ANS?
They are efferent: that is they take information away from the centre towards the periphery.
What is the main structural difference between the SNS and the ANS?
In the SNS, motor neurone of the CNS exert direct control over skeletal muscles.
In the ANS, motor neurones of the CNS synapse onto visceral motor neurones in autonomic ganglia, and these ganglionic neurones control visceral effectors.
What is the ANS divided into?
ANS innervation is divided into:
- sympathetic nervous system
- parasympathetic nervous system divisions.
What do the sympathetic and parasympathetic divisions of the ANS control?
Two divisions usually have opposing effects, but not always. Sometimes they control different parts of complex processes.
- Sympathetic division usually only ‘kicks in’ during periods of exertion, stress or emergency.
- Parasympathetic division predominates under resting conditions.
What are the alternative names for sympathetic and parasympathetic divisions, and why?
Sympathetic division is also called the thoracolumbar division: neurons begin at the thoracic and lumbar (T1-L2) portions of the spinal cord.
Parasympathetic division also called the craniosacral division: neurons begin at the cranial nerves (CN 3, CN7, CN 9, CN10) and sacral (S2-S4) spinal cord.
In what 2 main ways does the ANS exert control over visceral effectors?
- The sympathetic division can change the activities of tissues and organs by releasing NE at peripheral synapses, and by distributing E and NE throughout the body in the bloodstream.
- The visceral motor fibres that target specific effectors, such as smooth muscles in blood vessels can be activated in reflexes that do not involve other visceral effectors. In a crisis however the entire division responds.
What changes does a person experience with sympathetic activation? (6)
- Increased alertness via stimulation of the reticular activating system, causing the individual to feel on edge.
- A feeling of energy and euphoria, often associated with a disregard for danger.
- a temporary insensitivity to painful stimuli
- Increased activity in the CV and respiratory centres of the pons and the medulla oblongata, leading to elevation in blood pressure, heart rate, beating rate and depth of respiration
- A general elevation in muscle tone, so the person looks tense and may begin to shiver.
- The mobilisation of energy reserves throug the accelerated breakdown of glycogen in muscle and liver cells and the release of lipids by adipose tissue
What parts of the nervous system does sympathetic activation stimulate, and what is it controlled by?
This event called sympathetic activation is controlled by sympathetic centres in the hypothalamus. The effects are not limited to peripheral tissues, sympathetic activation also alters CNS activity.
What changes specific to promoting fight or flight occur with sympathetic activation? (8)
- Diverts blood flow away from the gastro-intestinal (GI) tract and skin via vasoconstriction.
- Blood flow to skeletal muscles and the lungs is enhanced (by as much as 1200% in the case of skeletal muscles).
- Dilates bronchioles of the lung, which allows for greater alveolar oxygen exchange.
- Increases heart rate and the contractility of cardiac cells (myocytes), thereby enhancing blood flow to skeletal muscles.
- Dilates pupils and relaxes the ciliary muscle to the lens, allowing more light to enter the eye and far vision.
- Provides vasodilation for the coronary vessels of the heart.
- Constricts all the intestinal sphincters and the urinary sphincter.
- Inhibits peristalsis.
What does the stimulation of the parasympathetic nervous system do?
- Promotes a “rest and digest” response, promotes calming of the nerves return to regular function, and enhances digestion.
- Dilates blood vessels leading to the GI tract, increasing blood flow. This is important following the consumption of food, due to the greater metabolic demands placed on the body by the gut.
- Constricts the bronchiolar diameter when the need for oxygen has diminished.
- Constriction of the pupil and contraction of the ciliary muscle to the lens, allowing for closer vision.
- Salivary gland secretion, and accelerates peristalsis so it mediates digestion of food and indirectly, the absorption of nutrients.
- Erection of genitals, via the pelvic splanchnic nerves 2–4.
- Stimulates sexual arousal
What is another name for the bystander effect?
What is the probability of receiving help inversely proportional to?
Genovese syndrome
The probability of help has in the past been thought to be inversely related to the number of bystanders; in other words, the greater the number of bystanders, the less likely it is that any one of them will help.
What is the link between the bystander effect and whether bystanders are friends of the victim?
increasing group size inhibited intervention in a street violence scenario when bystanders were strangers but encouraged intervention when bystanders were friends.
What are the two main reasons that bystanders do not help?
- The principal of social influence: bystanders monitor the reactions of other people in an emergency situation to see if others think that it is necessary to intervene. Since everyone is doing exactly the same thing (nothing), they all conclude from the inaction of others that help is not needed. This is an example of pluralistic ignorance or social proof.
- Diffusion of responsibility. This occurs when observers all assume that someone else is going to intervene and so each individual feels less responsible and refrains from doing anything.
What type of person would be (quite surprisingly) the least likely to help in an emergency situation?
Highly masculine subjects were less likely to take action to help the victim than were other subjects. Femininity and actual gender had no effect on likelihood of helping. Results suggests that highly masculine subjects fear potential embarrassment and loss of poise, so they may be reluctant to intervene in emergencies.
How does the perceived danger of a situation affect the bystander effect?
The bystander is more likely to help if the situation is perceived as dangerous (compared with non-dangerous), perpetrators were present (compared with non-present), and the costs of intervention were physical (compared with non-physical).
Consistent with the arousal-cost-reward model, which proposes that dangerous emergencies are recognized faster and more clearly as real emergencies, thereby inducing higher levels of arousal and hence more helping