Internal medicine -(73) Intensive therapy, emergency medicine, toxicology, acid-base disorders (73) Flashcards
INT - 15.1
The current 2015 European Resuscitation Council (ERC) adult Basic Life Support (BLS) guideline advises the procedures in the following order:
A) unresponsive – no pulse detected – resuscitation/emergency team contacted – 30 chest compressions – 2 breaths, 30 chest compressions
B) unresponsive – call for help – secure the airway – no breathing detected – resuscitation/emergency team contacted – 30 chest compressions – 2 breaths, 30 chest compressions
C) unresponsive – call for help – secure the airway – no breathing detected – resuscitation/emergency team alerted – 15 chest compressions – 2 breaths, 15 chest compressions
D) unresponsive – call for help – secure the airway – no breathing detected – resuscitation/emergency team alerted – 2 breaths, 30 compressions – 2 breaths, 30 compressions
ANSWER
B) unresponsive – call for help – secure the airway – no breathing detected – resuscitation/emergency team contacted – 30 chest compressions – 2 breaths, 30 chest compressions
EXPLANATION:
Outcome of cardiopulmonary resuscitation depends on the several links of the chain of survival. The first link is detecting cardiac arrest and calling for help. When assessing for signs of cardiac arrest the carotid pulse is not a reliable indicator. Also assessing breathing with unresponsive patients might be difficult for untrained helpers as well as medical personnel. The reason for this is that after cardiac arrest patients can continue to gasp for minutes in a much as 40% of the cases. Because of this CPR should be started if the patient is unresponsive and has no breathing or has gasping. Most adult cardiac arrests are of cardiac origin, therefor CPR should be started with chest compressions, rather than supplying breaths. No time should be wasted with looking for airway blockage, unless the supplied breaths do not produce adequate chest movements.
INT - 15.2
The current 2015 European Resuscitation Council (ERC) adult Basic Life Support (BLS) guideline permits cessation of chest compressions if the following occurs:
A) the defibrillator is charging
B) pulse is detected
C) the patient start moving, breathing, opens eyes
D) if the AED does not advise shock
ANSWER
C) the patient start moving, breathing, opens eyes
EXPLANATION
Chest compressions started in time and performed with the least possible interruptions significantly improve outcome during CPR. Because of this chest compressions should be continued even during the charging of the defibrillator and resumed right after defibrillation. If performed this way, interruption is less than 5 seconds. The person performing the compressions is not in danger, especially if wearing protective gloves. Feeling the lack of the carotid (or any other) pulse is not a reliable sign of cardiac and respiratory arrest. The AED only advises shock if a shockable rhythm (VF or pulseless VT) is detected, if a non-shockable rhythm is detected (be it compatible with normal circulation or not like asystole or PEA), a shock will not be advised. According to this, compressions should be ceased if the patients starts moving, breathing or opens eyes, which could all mark the return of spontaneous circulation.
INT - 15.3
Which of the following statements is false regarding chest compressions (according to the 2015 European Resuscitation Council Adult Basic Life Support guideline)?
A) optimal frequency of chest compressions is 100-120/min
B) depth of compressions should be 5-6 cm in adults
C) position of chest compressions: middle of the chest, lower half of sternum
D) CPR providers should be changed over after 5 minutes, because fatigue decreases compression quality
ANSWER
D) CPR providers should be changed over after 5 minutes, because fatigue decreases compression quality
EXPLANATION
A-B-C statements refer to the parameters and actions found to be the most hemodynamically effective in human studies. Fatigue however is present in most CPR providers after only 2 minutes, therefor if possible, a changeover is advised after 2 minutes. The changeover should not result in the interruption of chest compressions.
INT - 15.4
The following are all part of the 2015 European Resuscitation Council (ERC) adult Advanced Life Support guideline, except for one:
A) Check carotid pulse immediately after delivering shock.
B) When treating VF/pulseless VT adrenaline 1mg should be given after the 3. shock, after compressions have been resumed, the dose can be repeated after 3-5 minutes (in alternating cycles of CPR).
C) Routine use of atropine is not advised in asystole and PEA (pulseless electrical activity).
D) Targeted temperature management is advised most strongly after cardiac arrest with a shockable rhythm.
ANSWER
A) Check carotid pulse immediately after delivering shock.
EXPLANATION
Even if defibrillation is successful and results in a rhythm compatible with spontaneous circulation, it takes time for circulation to resume and it is very rare that the pulse is instantly palpable right after a shock. On the other hand, time spent searching for a pulse may lead to further loss of myocardium if there is no circulation present. Therefore, compressions should be resumed for 2 minutes after each shock, before we check the rhythm and look for a pulse. Routine use of atropine is not advised in cases of asystole or PEA. Asystole is usually caused by a primary myocardial cause rather than increased vagal tone, therefore there is no rationale for the use of atropine in asystole or PEA. Targeted temperature management was found to be neuroprotective in animal and human studies and might improve outcome after global cerebrals hypoxic-ischemic injury. There is strong evidence for the use of targeted temperature management in patients with cardiac arrest with a shockable rhythm who remain unresponsive after return of spontaneous circulation. For these patients a temperature control of 32-36°C is advised for 12-24 hours. The evidence for other cases of cardiac arrest is less convincing.
INT - 15.5
During cardiopulmonary resuscitation (CPR), if no high-risk intervention (e.g. Intravenous cannulation) is performed, what are possible transmittable diseases or agents?
A) Staphylococcus aureus, Streptococcus pyogenes, SARS, meningococcal meningitis
B) CMV
C) HIV, HBV, HCV
D) Mycoplasma, Chlamydia
ANSWER
A) Staphylococcus aureus, Streptococcus pyogenes, SARS, meningococcal meningitis
EXPLANATION
Some of the case reports that refer to disease transmission during CPR have included the following agents: Salmonella infantis, Staphylococcus aureus, SARS (severe acute respiratory syndrome), meningococcal meningitis, Helicobacter pylori, Herpes simplex virus, cutaneous tuberculosis, stomatitis, tracheitis, Shigella and Streptococcus pyogenes infections. In cases without high risk interventions (e.g. intravenous cannulation) there have been no cases described in the literature where HBV, HCV, HIV or CMV was transferred.
INT - 15.6
When assessing a patient with the ABCDE algorithm, the letters refer to the following, except:
A) Acute assessment of consciousness
B) Breathing assessment
C) Circulation assessment
D) Disability (neurological) assessment
E) Exposure assessment
ANSWER
A) Acute assessment of consciousness
EXPLANATION
During the ABCDE algorithm the A refers to airway: we first check the patency of airway which can be clear, in danger or obstructed. We can secure the airway with the head tilt/chin lift maneuver. B refers to breathing, when we assess the frequency, quality and symmetry of breathing movements and if possible the quality of oxygenation and ventilation. C stands for circulation, the assessment focuses on frequency and quality of the pulse, capillary refill time, signs of congestion, and if possible analyzing ECG rhythm and measuring blood pressure. D refers to disability, at which point we assess the level of consciousness and check for neurological symptoms. E stands for exposure, which might include assessing the probable cause of the current state of the patient including reviewing medical charts, listening to bystander accounts, checking for other signs and symptoms on the patient (e.g. bleeding, trauma).
INT - 15.8
A 32-year-old male is brought in to the emergency room by relatives after suffering an electric shock, he is unconscious and breathing. Which one of the following actions is necessary?
A) intubation if Glasgow Coma Scale is below 8
B) securing a central line
C) defibrillation with 200J if asystole is present
D) echocardiography
ANSWER
A) intubation if Glasgow Coma Scale is below 8
EXPLANATION
The patient is unconscious, but breathing which is a sign of maintained circulation. In this case we need to assess him according to the ABCDE algorithm. The first step is assessing and securing the airway. If the Glasgow Coma Scale (GCS) is below 8 the airway is considered to be in danger and the patient should be intubated in order to protect the airway. During assessment oxygen, monitoring and venous access (OMV) should be supplied. This patient needs surveillance for possible cardiac arrhythmias. Most common arrhythmias would include ventricular fibrillation or ventricular tachycardia, which are shockable rhythms. Asystole is a non-shockable rhythm, its treatment requires chest compressions and adrenaline. Venous access should be peripheral in this case. A central line would require more time and experience, would result in a higher complication rate and would only be indicated under special circumstances (e.g. failure to secure peripheral line, need for drugs requiring a central access, hemodynamic monitoring required) which are not present in this case. Echocardiography would be indicated later in the course of treatment, to assess cardiac function.
INT - 15.9
A patient with pneumonia treated in the ICU with mechanical ventilation develops increasing tachycardia, decreasing blood pressure on the fifth treatment day. Which of the following is not the probable cause?
A) septic shock
B) anaphylactic shock
C) normal hemodynamic consequences of arousal reaction
D) consequences of acute cardiac ischemia
ANSWER
C) normal hemodynamic consequences of arousal reaction
EXPLANATION
Pneumonia might result in sepsis and septic shock, which is consistent with tachycardia and decreasing blood pressure. Anaphylaxia can develop as a result of medications given at any time during the treatment with the above described symptoms. Cardiac ischemia can be a result of decreased oxygenation or the hemodynamic consequence of a septic state and should be excluded if the above-mentioned symptoms occur. Arousal reaction results in increased sympathetic activation, which would lead to tachycardia and increased blood pressure.
INT - 15.10
53-year-old female is admitted with acute right sided hemiplegia, deteriorating consciousness, respiratory distress, hypertension to the ICU with symptom onset in less than an hour. She is intubated and ventilated. Which of the following is incorrect?
A) Acute head CT scan is indicated.
B) Head of the bed should be elevated to 30°.
C) Goal of ventilation is controlled hypercapnia.
D) Thrombolysis with rt-PA (iv. 0,9mg/kg in 60 minutes) might be indicated.
ANSWER
C) Goal of ventilation is controlled hypercapnia.
EXPLANATION
Acute treatment of stroke depends on the origin (ischemic or hemorrhagic), so acute head CT scan is indicated to differentiate the two. Treatment of ischemic stroke with rt-PA thrombolysis within 3 (6) hours results in improving outcomes. Elevation of the head of the bed by 30 degrees improves venous flow and might help avoid the rise of intracranial pressure. Intracranial pressure can be affected by the change of arterial CO2 pressure. Hyperventilation and resulting hypocapnia causes cerebral vasoconstriction and diminished blood flow. Ongoing hypocapnia has a risk of cerebral ischemia. Weighing the risk and benefit, currently normocapnia or light hypocapnia is advised. Hyperventilation is only permitted for a limited period in situations of extreme ICP rise under monitored conditions. Hypercapnia is detrimental.
INT - 15.11
What is the primary goal of packed red blood cell transfusion?
A) Restoring intravascular volume.
B) Normalizing cardiac output.
C) Improving tissue perfusion.
D) Improving oxygen delivery.
ANSWER
D) Improving oxygen delivery.
EXPLANATION
The goal of packed red blood cell transfusion is to improve oxygen delivery. The intravascular volume can and should be restored with infusion therapy (crystalloid or colloid), which results in improved tissue perfusion and increased preload and subsequent increased cardiac output. This is proven by the fact that as much as an 80% loss of red blood cells is survivable if normovolemia is maintained. The critical hemoglobin concentration when transfusion is needed to maintain oxygen delivery is 7g/dL, but this is dependent on other factors influencing oxygen delivery such as cardiac output, oxygen saturation and oxygen consumption. See 15.7 for further information.
INT - 15.12
Which of the following is false regarding transfusions?
A) When deciding on a transfusion, universal trigger hemoglobin (Hb) levels should be used.
B) Transfusion is seldom indicated if Hb>10g/dL.
C) Transfusion is always indicated if Hb<6g/dL.
D) If normovolemia is present, as much as an 80% red blood cell loss is survivable.
ANSWER
A) When deciding on a transfusion, universal trigger hemoglobin (Hb) levels should be used.
EXPLANATION
When deciding on a transfusion no universal hemoglobin levels should be used. Transfusions are tissue transplantations with serious possible complications (e.g. infection). In the presence of anemia, tissue oxygenation is ensured with compensating mechanisms (increased cardia output, increased oxygen extraction rate, circulatory redistribution, shifting of the Hb dissociation curve to the right). No absolute number can be defined. Current oxygen demand, concurrent medical conditions (e.g. lung disease, atherosclerosis, ischemic heart disease), environment (e.g. altitude) can influence the transfusion trigger. Transfusion is seldom indicated with Hb levels > 10g/dl and is always indicated with Hb levels < 6g/dl. In the case of Hb: 6-10 g/dl special consideration is needed.
INT - 15.13
In regards to the oxygen-hemoglobin dissociation curve, the following are true except:
A) Increased pCO2 shifts the curve to the right.
B) Decreased 2,3-disfosfoglycerate (2,3 DGP) concentration shifts the curve to the left.
C) Decreased proton concentration shift the curve to the left.
D) Increased FiO2 (inspired oxygen fraction) shifts the curve to the right
ANSWER
D) Increased FiO2 (inspired oxygen fraction) shifts the curve to the right
EXPLANATION
The oxygen dissociation curve is shifted to the right by acidosis, increased paCO2, and increased temperature. The x axis shows the arterial oxygen tension (mmHg), the y axis shows the oxygen saturation of the arterial hemoglobin (%). A curve shifted to the right means that a certain saturation means higher oxygen content, hemoglobin discards oxygen molecules more readily. This is why mild acidosis is more beneficial for the tissues. Left shift can be caused by decreased 2,3-DPG level, alkalosis, oxygen is more securely bound to hemoglobin. Increase in the inspired fraction of oxygen does not shift the curve, only increases the partial oxygen pressure.
INT - 15.14
In the treatment of an unconscious patient with severe hemorrhagic shock, the first and most important step is:
A) transfuse with compatible red blood cell
B) place a central line to replace fluid and monitor central venous pressure
C) rapid infusion of crystalloids and/or colloids
D) secure the airway
ANSWER
D) secure the airway
EXPLANATION
Severe hemorrhagic shock treatment is done according to the ABCDE algorithm (A – airways, B – breathing, C – circulation, D – disability, E – exposure), so the first step is securing the airway. Parallel to this OMV (oxygen, monitoring, venous access) has to be started. Venous access includes two large bore (14G-16G) peripheral lines. Central venous access is only indicated if peripheral lines cannot be secured, since the complication rates are high and the central line permits smaller flow due to it being long and of a small diameter. The following treatment steps depend on the circumstances as well. If the location is ideal (emergency room), several steps can be performed simultaneously. Securing lines, taking blood sample and starting crystalloid/colloid solutions is the right order. Typing the blood takes time and should not delay infusion therapy.
INT - 15.15
According to current guidelines, when is acute percutaneous coronarography indicated in ST elevation myocardial infarction? (ESC STEMI guideline 2012)
A) Typical chest pain and ST elevation or probable new onset left bundle branch block (LBBB).
B) Typical chest pain and wall motion abnormality on echocardiography.
C) Typical chest pain or LBBB and elevated ectoenzymes.
D) ST elevation or probable new onset LBBB, elevated ectoenzymes and wall motion abnormality on echocardiography.
ANSWER
A) Typical chest pain and ST elevation or probable new onset left bundle branch block (LBBB).
EXPLANATION
According to current guidelines (ESC STEMI guideline 2012), in the case of ST elevation myocardial infarction typical chest pain and ST elevation or probable new onset LBBB on ECG are sufficient indication for acute percutaneous coronarography to be performed. Necroenzyme elevation and wall motion abnormality on echocardiography are signs of definite ischemic injury. Time equals myocardium, so therapeutic intervention is recommended if the conditions in the A answer are verified.
INT - 15.16
Most effective way to diagnose cardiac tamponade:
A) Electrocardiogram
B) Echocardiography
C) Chest X-ray
D) Right heart catheterization
ANSWER
B) Echocardiography
EXPLANATION
Cardiac tamponade includes fluid in the pericardium resulting in diastolic dysfunction and hemodynamic instability. The pressures of the left atrium, the pulmonary circulation, the right atrium ad the superior caval vein equilibrate, which leads to hemodynamic collapse. 2D echocardiography can identify pericardial fluid, its amount, location and hemodynamic effect as well as the feasibility of pericardiocentesis. Cardiac tamponade signs are the collapse of the right atrium, mitral regurgitation, later left atrium and right ventricle collapse. Right heart catheterization can also identify effects of pericardial fluid buildup, but this intervention is invasive and is in use in cardiac surgery centers. Chest X-ray can show increased cardiac volume in 50% of cases, but does not show congestion. ECG signs might be low voltage, ST segment elevation.
INT - 15.17
All of the statements regarding succinylcholine use are true except for one. Mark the false statement:
A) Succinylcholine is contraindicated in hyperkalemia, burn patient, paraplegia.
B) Side effects include muscle pain, bradycardia, malignant hyperthermia.
C) Effects of succinylcholine can be counteracted with neostigmine.
D) Succinylcholine can be used for the intubation of patients with a full stomach.
ANSWER
C) Effects of succinylcholine can be counteracted with neostigmine.
EXPLANATION
Succinylcholine is the only current depolarizing muscle relaxant in use. Its binding to the nicotinerg acetylcholine receptors of the end plates results in sustained depolarization. The effect is muscle fasciculation starting in the facial muscles, spreading caudally and completing in the diaphragm. As a result of the muscle activation intracellular potassium release occurs with concurrent muscle pain. Bradycardia is a side effect caused by hyperkalemia and nonspecific activation of acetylcholine receptors. Hyperkalemia, extensive burns, muscle dystrophy can result in critically elevated potassium levels, so these are contraindications. Succinylcholine is a potent malignant hyperthermia trigger. Succinylcholine is hydrolyzed by plasma cholinesterase, it cannot be counteracted with neostigmine. It has a short onset (30-60s), and is therefore used in full stomach intubation scenarios. These patients are not ventilated manually before intubation for risk of stomach distension and aspiration, so onset of muscle paralysis needs to be quick.
INT - 15.18
Which of the following is not part of first line treatment for anaphylaxia?
A) oxygen
B) infusion therapy
C) vasoactive treatment
D) antihistamines
ANSWER
D) antihistamines
EXPLANATION
Treatment of anaphylaxia is adrenaline. It has bronchodilator, chronotropic and inotropic effect through β-receptors of the bronchi and heart and vasoconstrictor effects through the α-receptors of vessels. Through increasing intracellular cAMP- (cyclic adenosine monophosphate) levels, it prevents mastocyte and circulating basophil activation. Emergency treatment includes OMV (oxygen-monitor-venous access): administering oxygen, starting monitoring, providing two large bore (at least 18G) peripheral lines anaphylactic shock is distributive, vasoactive therapy has to be parallel to infusion therapy. Antihistamines are limited to localized, not severe cases, in actual anaphylaxia they are considered to be second line treatment if ongoing symptoms remain.
INT - 15.19
Which of the following are SIRS (Systemic Inflammatory Response Syndrome) criteria (as per American College of Chest Physicians and Society of Critical Care Medicine ACCP/SCCM 1991 Consensus)?
A) temperature > 37°C
B) heart rate > 80/min
C) respiratory rate > 25/min
D) WBC > 12 000/mm3 or < 4000/mm3 or > 10% immature neutrophils
ANSWER
D) WBC > 12 000/mm3 or < 4000/mm3 or > 10% immature neutrophils
EXPLANATION
Systemic Inflammatory Response Syndrome is the reaction of the body to any tissue harming effects, resulting in several characteristics. The above mentioned Consensus Conference defined SIRS as a syndrome with at least two of the following four criteria present: abnormal body temperature (>39°C or <36°C), tachycardia (>90/min), tachypnoea (respiratory rate >20/min or PaCO2<32 mmHg), leukocytosis or leukopenia (WBC >12 000/mm3 or <4000/mm3 or >10% immature neutrophils).
INT - 15.21
According to the Surviving Sepsis Campaign the following should be achieved within an hour of the initial treatment of a septic patient:
A) microbiological sampling and starting of adequate antibiotic treatment
B) identifying the microorganism by PCR
C) 2000mL iv. crystalloid
D) surgical source control
ANSWER
A) microbiological sampling and starting of adequate antibiotic treatment
EXPLANATION
The goal of the Surviving Sepsis Campaign is improving patient outcome by standardizing the treatment of septic patients. Adequate treatment includes microbiological sampling, starting of adequate antibiotic treatment, stabilization of cardiovascular parameters (iv. fluid resuscitation and vasopressor therapy). Microbiological sampling and initiation of antibiotic therapy should be done as soon as possible, preferably within an hour. Identifying the microorganism with PCR can be a helpful diagnostic step with fulminant conditions, but is not routinely used because of its ow specificity and high cost. Adequate fluid resuscitation is advised with a goal of 30mL/kg during the first three hours. Surgical source control is achievable with certain well-defined conditions (abscess, isolated phlegmon) and should be done as soon as feasible, but most septic conditions do not permit surgical source control (e.g. pneumonia, urinary sepsis).
INT - 15.22
Pharmacological treatment of a patient with septic shock includes:
A) Vancomycin, if shock has been present for more than two days
B) high dose methylprednisolone, if shock in unresponsive to iv. fluids
C) insulin, if blood glucose is >10mmol/L
D) dobutamine, if tachycardia persists
ANSWER
C) insulin, if blood glucose is >10mmol/L
EXPLANATION
Vancomycin is a wide spectrum bactericide glicopeptide antibiotic with poor tissue penetration. Currently it is viewed as a „rescue antibiotic” in cases of severe, resistant Staphylococcus and Enterococcus infections and therefore empirical use is not advised. Corticosteroid therapy is only suggested in cases of cardiovascular instability despite iv. fluid therapy and vasopressor therapy. Mortality is not improved but hemodynamic stability is better achieved. The guideline suggests the use of hydrocortisone 200mg/day in 3-4 divided doses. Increased doses do not positively effect survival but might result in several complications. Strict glucose control (4-8mmol/L) increases mortality with critically ill patients. But high blood glucose levels also worsen outcome. The current Surviving Sepsis guideline recommends keeping blood glucose levels below 10mmol/L. Dobutamine has β agonist effects, which might contribute to vasoplegia in septic shock (β2 effect) with concomitant tachycardia (β1 receptor effect). First line vasopressor treatment therefore is norepinephrine. Dobutamine can be used additionally if inotropic support in needed.
INT - 15.23
The goal of fluid resuscitation in a septic patient is:
A) CVP > 20 mmHg
B) MAP > 65 mmHg
C) diuresis > 1,5mL/kg/h
D) ScvO2 > 30%
ANSWER
B) MAP > 65 mmHg
EXPLANATION
The goal of fluid resuscitation in septic shock is to restore adequate perfusion, which can be monitored via surrogates in intensive care. These surrogates include normalization of CVP (8-12 mmHg), MAP (>65 mmHg), diuresis (>0,5ml/kg/h) and central venous oxygen saturation (>70%) values.
INT - 15.24
Nutrition goal for a patient treated with urosepsis and septic shock includes:
A) enteral nutrition
B) parenteral nutrition
C) reduced protein enteral nutrition
D) enteral nutrition with parenteral supplementation if goal calorie intake is not reached within day 2
ANSWER
A) enteral nutrition
EXPLANATION
The goal of nutritional therapy in septic patients is to provide the goal caloric intake with enteral nutrition, which results in improved survival. Total parenteral nutrition is only advised if the enteral route is not feasible. If calorie intake is not reached with enteral nutrition, parenteral supplementation is not recommended within the first 7 days. If the enteral route is not sufficient, parenteral supplementation can be used after 7 days. Sufficient protein intake improves survival in septic patients, so protein restriction should not be used.
INT - 15.25
23-year-old female is admitted to the ICU because of asthma. Invasive mechanical ventilation is started. Which of the following is not true regarding initial ventilation settings?
A) Minimizing dynamic hyperinflation is key, so expiratory time should be long and PEEP should be low.
B) High inspiratory pressures should be avoided at all costs, since pressure correlates with barotrauma and mortality.
C) FiO2 should be adjusted to reach a SatO2 >94%
D) Minute ventilation should be as low as possible to minimize dynamic hyperinflation.
ANSWER
B) High inspiratory pressures should be avoided at all costs, since pressure correlates with barotrauma and mortality.
EXPLANATION
In severe asthma the goal of mechanical ventilation is to minimize dynamic hyperventilation caused by small airway obstruction and tachypnoea, as well as to maintain adequate oxygenation. In the case of severe small airway obstruction, the optimal ventilation is slow (8-13/min), with a balanced I:E ratio and minimal needed PEEP, so slow alveoli can also deflate. Inspiratory pressures can be quite high because of increased airway resistance, but this does not corelate with barotrauma or mortality (rather these are directly influenced by dynamic hyperinflation). Oxygenation can be improved by adjusting FiO2to avoid hypoxia, but supranormal oxygen values are not the goal.
INT - 15.26
Which of the following blood gas values is most indicative of acute respiratory failure in a patient suffering from acute exacerbation of COPD?
A) pH < 7,3
B) paO2 < 60 mmHg
C) paCO2 > 50 mmHg
D) HCO3 > 30 mmHg
ANSWER
A) pH < 7,3
EXPLANATION
Chronic obstructive pulmonary disease results in characteristic changes in blood gas values. Arterial pressure of O2 is reduced. Hypoxia develops slowly, so patients have time to adjust (e.g. with polycythemia), so it’s possible for some patients to tolerate paO2 values as low as 40-50 mmHg without subjective symptoms. In acute respiratory failure hypoxia worsens but comparisons to chronic values are helpful in identifying whether the hypoxia is acute. The paCO2 value is usually elevated because of chronic respiratory failure (in most patients between 40-60 mmHg). Respiratory acidosis is compensated by elevation of bicarbonate levels, so this is indicative of chronic respiratory failure. In acute respiratory failure paCO2 is further increased which is not quickly compensated metabolically, resulting in acidosis. This is why pH abnormalities are the most indicative of acute respiratory failure in these patients.
INT - 15.27
In the treatment of acute exacerbation of COPD oxygen therapy is carefully titrated because:
A) oxygen therapy does not improve outcomes in chronically hypoxic patients
B) oxygen therapy reduces respiratory drive
C) oxygen therapy results in CO2 retention because of diminished hypoxic vasoconstriction
D) anaerobe metabolism is more energy efficient
ANSWER
B) oxygen therapy reduces respiratory drive
EXPLANATION
Oxygen therapy is beneficial in hypoxic COPD patients, with long term therapy improving mortality and morbidity. In acute exacerbation oxygen should be carefully titrated to avoid CO2 retention. Hypoxia causes vasoconstriction in pulmonary capillaries, so oxygen therapy improves perfusion in hypoventilated parts leading to high CO2 content entering the circulation, resulting in CO2 retention or coma. Anaerobe metabolism is always less efficient than aerobic.
INT - 15.28
NIV (noninvasive ventilation) is an important treatment option in acute exacerbation of chronic obstructive pulmonary disease (COPD) with the right indications, except:
A) it has fewer complications than invasive ventilation
B) it results in less mucus dehydration than invasive ventilation
C) with appropriate settings 80% of patients report improving symptoms
D) it unloads respiratory muscles
ANSWER
B) it results in less mucus dehydration than invasive ventilation
EXPLANATION
Noninvasive ventilation is supplied through a nasal or face mask and supports spontaneous breathing. Several studies have shown that NIV use in acute exacerbation of COPD improves outcome. Avoiding overloading and atrophy of respiratory muscles is vital in these patients, so promoting adequate, spontaneous breathing is important. At the same time NIV is not invasive and results in less nosocomial infections than invasive ventilation. Most NIV systems are high flow systems with increased mucosa drying effect, so adequate humidification is important. With the right indication and settings most patients (about 80%) tolerate ventilation well, with improving oxygenation, reduced CO2 retention and acidosis.
INT - 15.29
The following is not true regarding acute kidney injury (AKI):
A) origin in intensive care is usually prerenal
B) intraabdominal pressures above 25 mmHg promote AKI
C) high dose diuretic therapy can stop progression of AKI
D) NSAID therapy can promote progression of AKI
ANSWER
C) high dose diuretic therapy can stop progression of AKI
EXPLANATION
Acute kidney injury is produced by acute effects diminishing kidney function, resulting in diminished glomerular filtration rate, increased serum creatinine and reduced diuresis. Etiology can be prerenal, renal and postrenal with prerenal being the most common cause in intensive care settings. Prerenal causes can be reduced perfusion of the kidneys as a result of hemodynamic instability or increased intraabdominal pressure. Renal causes are usually toxic (e.g. NSAID promoted) or infection related parenchymal injury, while postrenal causes usually include urolithiasis, tumor or iatrogenic obstruction of urinary flow. Progression of kidney injury can be slowed or stopped by reversing the causes (e.g. stabilizing hemodynamic parameters, lowering intraabdominal pressure, avoiding toxins, resolving urinary obstruction). Diuretics increase rate of diuresis, but do not slow progression of AKI (but can rather hasten it).
INT - 15.30
A mechanically ventilated, hemodynamically stable and normovolemic 24-year-old polytrauma patient has the following parameters on day 4. following trauma: serum creatinine 400 umol/L; diuresis: 30ml/h, pH 7,3; BE: -11, HCO3: 13mmol/L. Which of the following is advised first?
A) 1-5ug/kg/min dopamine drip
B) combination of osmotic and loop diuretics
C) at least 2L positive fluid balance to improve hydration
D) renal replacement therapy
ANSWER
D) renal replacement therapy
EXPLANATION
Acute kidney injury after polytrauma is prerenal and renal in origin (shock, rhabdomyolysis, contrast induced kidney injury). Since this patient is hemodynamically stable and normovolemic, additional iv. fluid therapy will not be beneficial, on the contrary positive fluid balance might be harmful. „Renal dose” dopamine apart from increasing diuresis has no clinically proven beneficial effects in kidney injury, and is hence not advised. No diuretics have proven beneficial effects, and in this case osmotic diuretics can worsen rhabdomyolysis induced kidney injury. The parameters described here verify stage III AKI, so renal replacement therapy is indicated.
INT - 15.31
When treating a patient with acute kidney failure in intensive care which of the following is true:
A) antibiotic dose should be adjusted according to renal clearance.
B) Dose of LMWH (low molecular weight heparin) treatment should be increased because of increased thrombosis risk.
C) Parenteral nutrition should be protein free due to the risk of protein intoxication.
D) All of the above.
ANSWER
A) antibiotic dose should be adjusted according to renal clearance.
EXPLANATION
In acute renal failure drug elimination is reduced, so normal drug doses result in cumulation of chemicals and increased complication rates. Antibiotic dosing should be adjusted based on serum drug levels or according to previously verified dosing schemes based on clearance. Heparins also tend to cumulate; their dose should be reduced. Acute renal failure results in protein catabolism, resulting in increased protein need of 0,6-1g/kg/day.
