e11CHAPTER 136 Board Review Questions Chapter 12 Prediction Tools for Short Term Outcomes Following Critical Illness in Children 1 A 4 year old previously healthy boy is admitted to the inten sive car[.]
CHAPTER 136 Board Review Questions Chapter 12: Prediction Tools for Short-Term Outcomes Following Critical Illness in Children A 4-year-old previously healthy boy is admitted to the intensive care unit with septic shock He is intubated on arrival to the unit, started on broad spectrum antibiotics, and fluid resuscitated He has ongoing hypotension and multiple vasoactive infusions are initiated His laboratory studies demonstrate evidence of disseminated intravascular coagulation (DIC) and his most recent arterial blood gas analysis demonstrates a severe metabolic acidosis with a lactate of The resident on call tells you that his Pediatric Risk of Mortality (PRISM) score two hours after admission is 19 The most correct interpretation of the PRISM score in this patient is: A His risk of mortality during this admission is 19% B His risk of mortality in the next two hours is 19% C It cannot be interpreted because he has not yet been fully resuscitated D It cannot be interpreted because he has not yet been admitted long enough E It cannot be interpreted because PRISM does not apply to individual patients Preferred response: E Rationale PRISM scores are not designed to be interpreted for an individual patient, but instead provide a mechanism by which case-mix can be measured over a large group of patients PRISM scores are calculated during the first hours of a patient’s admission to the ICU and include physiologic and laboratory data for hours prior to and hours after admission This time limitation is intended to more accurately represent a patient’s presenting physiologic status, as opposed to the provision of intensive care As part of a quality improvement initiative, a colleague has created a model to examine patients at risk of developing pressure injuries while in the intensive care unit She reports in a divisional research meeting that the discrimination of the model is 0.92 Which of the following is the most correct interpretation of this value? A The model’s overall sensitivity is 92% B The model’s overall specificity is 92% C The positive predictive value of the test is 92% D 92% of variation in a patient’s likelihood of developing a pressure injury is explained by the model E 92% of patients with pressure injuries will meet all the components of the model Preferred response: B Rationale Discrimination is a model’s ability to correctly differentiate patients with a specified outcome from those without the outcome This is in contrast to calibration, which is the model’s ability to predict overall event rates The model’s discrimination is often reported as the C statistic, which represents the average sensitivity of the model over the range of possible specificity values e11 A fellow is planning a research project to study patient risk factors for mortality in patients with traumatic brain injury She is hoping to include patients from multiple centers and would like your advice about how to control for variation in risk between hospitals Which of the following is most useful for the research team to assess? A The sample size from each hospital B The standardized mortality ratio for each hospital C The hospital length of stay for each included patient D The yearly number of traumatic brain injury patients admitted to each hospital E The presence or absence of neurosurgical services at each hospital Preferred response: B Rationale Standardized mortality ratios represent the ratio of observed to expected mortalities and provide a mechanism by which researchers can control for case mix variation between institutions This can help to isolate patient characteristics, which are of interest to the fellow, from systems-level characteristics While the other choices represent important considerations, the standardized mortality ratio is most important to allow for control A 4-month-old former 35-week gestational age girl is admitted to the intensive care unit for hypoxic respiratory failure requiring mechanical ventilation She was intubated at an outside hospital and was started on broad spectrum antibiotics for concern for pneumonia with an elevated white blood cell count (WBC) and infiltrate on chest radiograph As part of her admission process, the bedside nurse completes a worksheet with information for the Pediatric Risk of Mortality (PRISM) score as well as the Paediatric Index of Mortality-3 (PIM3) score Which of the following pieces of information will be included in the PIM3 but not PRISM? A The pH from an arterial blood gas obtained one hour after admission B The measured systolic blood pressure at admission C The results of pupillary reflex testing D The fact that the child is undergoing mechanical ventilation E The measured WBC obtained at the outside hospital one hour prior to admission Preferred response: D Rationale Both PIM3 and PRISM include evaluation of physiologic and clinical data for a patient but the methods differ slightly in the amount of included data, the observation period, and inclusion of nonphysiologic data Specifically, PIM3 includes mechanical ventilation within an hour of admission, while PRISM includes more laboratory values Both scoring systems include evaluation of systolic blood pressure and pupillary reflexes e12 S E C T I O N XV Pediatric Critical Care: Board Review Questions A researcher develops a model to predict the risk of patients admitted to the PICU of developing a deep venous thrombosis based on a number of demographic and clinical factors The model is developed on 1000 patients with an area under the receiver operating characteristic curve (AUC) of 0.8 The model is subsequently validated on a separate dataset of 1000 patients with an AUC 0.7 What term best describes the model’s performance as quantified by the AUC? A Calibration B External validity C Discrimination D Internal validity Preferred response: C Rationale Discrimination is the accuracy of a model in differentiating outcomes groups and is most often assessed by the AUC External validity is the extent to which the results of a study can be generalized to other situations and other people External validity is typically assessed through the process of study replication Calibration refers to the ability of a model to assign the correct probability of outcome to patients over the entire range of risk prediction The most accepted method for measuring calibration is the Hosmer-Lemeshow goodness-of-fit test Internal validity relates to the extent to which a causal conclusion based on study findings is warranted and is assessed by the degree to which the study design minimized systematic error or bias The precision of a measurement system is the degree to which repeated measurements under unchanged conditions show the same results A previously healthy 7-year-old male is admitted to the PICU of a tertiary care children’s hospital in septic shock secondary to lobar pneumonia He is tachycardic (heart rate, 130 beats per minute) and tachypneic (respiratory rate, 55 breaths per minute) and undergoes intubation of the trachea within 30 minutes of PICU admission for respiratory failure Arterial blood gas reveals pH 7.2, Paco2 40 mm Hg, Pao2 80 mm Hg, and HCO2 12 mEq/L on Fio2 of 0.6 Coagulation studies reveal an elevated INR 1.8 Which scoring system is most appropriate to assess this patient’s physiologic status on the initial day of PICU admission? A PELOD B PRISM III C SNAPPE-II D STS-EACTS score Preferred response: B Rationale CRIB II and SNAPPE-II are scoring systems for neonates STS-EACTS score was developed for patients with congenital heart disease PELOD is a scoring system designed to quantify the degree of organ dysfunction in PICU patients and correlates well with mortality PELOD, however, is calculated based on the greatest degree of physiologic dysfunction to occur at any point during the entire PICU admission, not just the initial day of admission PRISM III is a physiology-based acuity score that is calculated in the interval from the hours preceding PICU admission to hours following PICU admission 7 You are asked to accept the transfer of a 2-year old child with respiratory failure secondary to viral pneumonitis from a rural emergency department (ED) The child was seen and discharged from that ED days ago This morning, her parents awoke to her loud breathing and called emergency medical services The emergency medical technicians assessed the child, determined that she had respiratory failure, stabilized her airway, provided bag-valve-mask ventilation with oxygen, and provided respiratory treatments during transport to the local ED They notified the ED of the child’s condition The ED is performing additional steps for stabilization, along with some diagnostic tests, including a chest radiograph and basic laboratory studies The ED has explained to the family that their child will need to be transported to the local children’s hospital, and someone from the ED is calling you for a helicopter transport This scenario demonstrates appropriate system design for the critically ill child around which of the following issues? A Access B Cost C Outcome D Process Preferred response: A Rationale Systems are designed to facilitate easy access to services for those who need them Access (response A) describes organized and integrated care for critically ill children and their families who are in need of tertiary pediatric services Cost (response B) is an important element of healthcare delivery that focuses on the monetary resources devoted to patient care However, economic terms are not discussed in this scenario Research is an important activity in generating new knowledge, but this scenario is concerned with the delivery of care to an individual patient Although the child ultimately may be enrolled in a research project or database evaluating outcomes, research is not the primary focus of her care Process measures (response D) are those that occur between patients and providers or between various providers Although a number of clinical processes have occurred in the scenario, the scenario also includes a number of interactions between other structural components, such as institutions and emergency services, which establish an organized hierarchy of interactions for the delivery of care The final outcomes of care from the ICU perspective (response C) are not discussed in the scenario Although the child was effectively rescued and delivered to the rural ED and a number of intermediate outcomes may be described, the final outcomes in terms of vitality, economics, or morbidity are yet to be determined Therefore, the most appropriate answer is A After the first ICU day, the child’s PRISM III score is What should you do? A Ignore the score for today B Remove the child from mechanical ventilation and provide comfort care C Rescore the patient using the Pediatric Index of Mortality (PIM) D Recognize that this score is correlated with a population risk of mortality Preferred response: D CHAPTER 136 Board Review Questions e13 Rationale Rationale The PRISM score is a physiologically based severity of illness measure calculated from variables determined within the first 24 hours of care It is helpful for understanding the risks for mortality and length of stay for populations of patients with a given severity of illness However, the score cannot be applied for prognostication at the level of individual patients; hence it should not be used to guide clinical decisions as suggested in response B Repetitive scoring using PRISM during hospitalization (response A) has not been validated Using the PIM (response C), which captures care at the point of admission rather than at 24 hours, provides a different measure of severity that also can be compared across populations Importantly, a bias exists in relation to the inclusion of mechanical ventilation as a predictor variable in PIM Therefore the most appropriate answer is D Boyle’s law (P1V1 P2V2) describes the relationship between pressure and volume of a gas in an enclosed space at a constant temperature Given that this patient will be rising in altitude, atmospheric pressure is expected to decrease with increasing height Any gases trapped in enclosed spaces are expected to expand proportionately to any decreases in atmospheric pressure Substituting the known pressures and volumes into the equation allows for calculation of the unknown cuff volume at the highest altitude: Chapter 13: Pediatric Critical Care Transport What is the most common mode of inter-facility transport for pediatric patients? A Ferry B Fixed-wing C Ground D Rotor-wing Preferred response: C (741 630 V2 ) V2 2.4 mL According to the Emergency Medical Treatment and Labor Act (EMTALA) established by the COBRA legislation, an appropriate transfer criterion includes which of the following? A The referring hospital must provide care and stabilization within its ability B The referring physician certifies that the medical benefits expected from the transfer outweigh the risks C The referring physician consents to transfer after being informed of the risks of transfer D The receiving facility must have available space and qualified personnel and agree to accept the transfer Preferred response: B Rationale Rationale The advantages of ground transport include easier and direct access to referring and receiving locations, lower cost, and ability to respond in most weather conditions Circumventing traffic rules via use of lights and sirens does not improve the outcomes of pediatric transports and significantly increase the risk of an accident Rotor-wing (helicopter) transport may be faster than ground transport for patients located 45–60 miles away from admitting institution, particularly in geographically challenging areas such as waterways, and can help to minimize out-of-hospital time Fixed-wing transports are typically reserved for long-distance flights and have the ability for cabin pressurization Disadvantages of both rotor-wing and fixed-wing transports are limited space and high cost EMTALA delineates rules for inter-facility transfer Appropriate transfers must meet the following criteria: (1) the transferring hospital must provide care and stabilization within its ability; (2) the referring physician certifies that the medical benefits expected from the transfer outweigh the risks; (3) the patient consents to transfer after being informed of the risks of transfer; (4) the receiving facility must have available space and qualified personnel and agree to accept the transfer; (5) copies of medical records and imaging studies should accompany the patient; and (6) the inter-facility transport must be made by qualified personnel with the necessary equipment 2 A pediatric patient is intubated for acute respiratory failure secondary to pneumonia at a critical access hospital and now requires rotor-wing transport to the nearest pediatric intensive care unit for ongoing care The referring facility is located at an altitude of 718 ft above sea level where the atmospheric pressure is 741 mm Hg The flight path will take the patient over a mountain pass with an unpressurized cabin altitude equivalent to 5100 ft above sea level and an atmospheric pressure of 630 mm Hg If the endotracheal tube cuff is inflated with mL of air prior to departure from the referral facility, what is the expected volume of air in the cuff when at the highest altitude? A 1.5 mL B 2.4 mL C 3.0 mL D 3.2 mL Preferred response: B Which of the following characterizes a typical skilled inter- facility pediatric transport team in comparison to care providers at a referring hospital? A Administration of drugs not typically available at nontertiary centers B Aggressive, early institution of simple therapies C Availability of superior airway and breathing support modalities D Superior diagnostic capabilities Preferred response: B Rationale For most pediatric critical illnesses, definitive care, ideally beginning with a skilled inter-facility transport team, does not involve miracle drugs or technologies but rather the early, aggressive administration of simple therapies Therapy that includes timely initiation of resuscitation fluids, early administration of inotropes (frequently via peripheral intravenous or intraosseous catheters), and early antibiotic therapy can improve outcomes e14 S E C T I O N XV Pediatric Critical Care: Board Review Questions Chapter 14: Pediatric Vascular Access and Centeses Which of the following is a recommended practice to reduce catheter-related blood stream infections (CRBSI) from central venous catheters (CVC)? A Full barrier precautions at the time of insertion B Giving all intravenous antibiotics through the catheter C Povidone-iodine ointment applied to insertion site daily D Vancomycin containing heparin flushes Preferred response: A Rationale CRBSI is the most common complication related to CVCs In children, the location of the insertion site is not related to infection risk The risk of infection is decreased by the use of a bundle of practices during insertion and ongoing maintenance of the CVC The insertion bundle includes strict maximal sterile barrier precautions and aseptic technique Dressing changes with chlorhexidine skin prep, minimizing catheter access, and daily assessment of the need of the catheter are all recommended as a part of CVC maintenance Antimicrobial-impregnated catheters may decrease the risk of catheter-related infection, but more pediatric studies are needed Which of the following is the most common complication of intraosseous (IO) infusion? A Fat embolus requiring mechanical ventilation B Fracture requiring internal fixation C Hypercalcemia from bone demineralization D Infiltration of fluids into the surrounding tissues Preferred response: D Rationale Significant complications of IO insertion and infusion are rare The most common complication is extravasation of fluid The causes of extravasation include incomplete penetration of the bony cortex, movement of the needle such that the hole is larger than the needle, dislodgment of the needle, penetration of the posterior cortex, and leakage of fluid through another hole in the bone, such as a previous IO site or fracture Extravasation of a small amount of fluid is usually not problematic, but with larger volumes, compartment syndrome can develop and may require fasciotomy and even amputation Use of the IO line for prolonged periods or with pressure bags increases the risk for this complication If extravasation occurs, the needle should be removed, and the extremity diligently observed for signs of compartment syndrome Experience to date suggests that the complications of the new mechanical insertion devices are similar to manual IO needle use Other rare complications include infection and bone fracture Osteomyelitis, cellulitis, and sepsis have been reported in conjunction with IO infusion Risk for infection is increased when IO access is prolonged, and these devices are used in patients with bacteremia 3 Ultrasound guidance for needle pericardiocentesis should be standard practice for which of the following indications? A Cardiac tamponade with ongoing cardiopulmonary resuscitation B Elective pericardiocentesis with idiopathic pericarditis C Penetrating trauma of the right ventricle D Second procedure after a failed blind, landmark-based attempt Preferred response: B Rationale Except in life-threatening tamponade, ultrasound imaging should be used to improve success and reduce complications Drainage of a pericardial effusion due to any cause is absolutely indicated when cardiac tamponade is present Often drainage is recommended if the effusion is large, even in the absence of tamponade, for diagnosis and fluid removal For small effusions, pericardiocentesis may be indicated for diagnosis alone With purulent pericarditis, open surgical drainage may be more effective because of the difficulty in draining purulent exudate Traumatic pericardial effusions secondary to penetrating trauma often require surgical drainage of the blood, because tamponade is common Pneumopericardium secondary to pulmonary air leaks in mechanically ventilated patients is usually well tolerated hemodynamically but may require drainage, especially in small infants, because of the development of tamponade There is no absolute contraindication to pericardiocentesis in an emergency situation The presence of aortic dissection or myocardial rupture is considered a major contraindication The presence of a bleeding diathesis or coagulopathy is another contraindication Open drainage is preferred over closed drainage when the patient has traumatic tamponade and is in cardiac arrest When the effusion is loculated in a location not easily reached via the subxiphoid approach, needle pericardiocentesis is contraindicated because the risk of complications increases, while the possibility of successful drainage is low Which of the following is most consistent with an exudative pleural effusion? A Pleural to serum lactate dehydrogenase (LDH) ratio , 0.4 B Pleural fluid LDH , the upper limit of normal serum LDH value C Pleural to serum protein ratio 0.5 D Pleural fluid WBC count ,5% of peripheral WBC count Preferred response: C Rationale Analysis of pleural fluid is separated into two basic diagnostic categories: exudates and transudates Transudates arise from imbalances of hydrostatic or oncotic pressures, such as seen in congestive heart failure or nephrotic syndrome Exudates can be caused by a variety of mechanisms, most commonly from pleural and lung inflammation or impaired lymphatic drainage The criteria used to distinguish between the two have evolved, but are rooted in Light’s Criteria Rule (see below) The updated combination of two or more of these criteria increases the diagnostic sensitivity for the rule More recent diagnostic rules, including the “two-test rule” and “three-test rule,” include pleural fluid cholesterol level greater than 45 mg/dL and not require concomitant serum levels to be obtained CHAPTER 136 Board Review Questions Additional pleural fluid studies should be sent to aid in diagnosis, especially fluid for culture, cell count with differential, and cytology Low pleural glucose (,60 mg/dL) and pleural pH (,7.3) with very elevated nucleated cell counts (.50,000/mL) are highly suggestive of empyema Elevated pleural triglyceride levels (.110 mg/dL) and lymphocyte predominance suggest chylothorax, while triglycerides ,50 mg/dL effectively rule it out Elevated amylase suggests pancreatitis or esophageal rupture Advances in polymerase chain reaction (PCR) technology allow for rapid and accurate diagnosis of viruses and bacteria in pleural fluid Light’s criteria rule for diagnosing exudative effusions are as follows: If at least one of the following present, effusion defined as exudate: • Pleural to serum protein ratio 0.5 • Pleural to serum lactate dehydrogenase (LDH) ratio 0.6 • Pleural fluid LDH more than twice the upper limit of normal serum LDH value Which of the following is suggestive of spontaneous bacterial peritonitis when evaluating fluid obtained from a paracentesis? A Ascitic fluid glucose 22 mg/dL with serum glucose 110 mg/dL B Multiple organisms in the culture C Neutrophils 250/mm3 D Total protein 2.2 g/dL Preferred response: C Rationale Condition Clinical Characteristics Laboratory Findings Spontaneous bacterial peritonitis Cloudy or turbid Gram stain positive ,10%, cultures may be negative, single organism Neutrophils 250/mm3 Total protein ,1 g/dL LDH and glucose similar to serum Initial management of limb ischemia after arterial catheterization should include which of the following? A Aspirin and local application of nitroglycerin paste B Catheter removal and systemic heparin anticoagulation C Local infusion of alteplase D Thrombectomy within hours Preferred response: B Rationale Limb ischemia that develops after arterial catheterization first requires immediate catheter removal If ischemia does not rapidly resolve and no contraindications to anticoagulation exist, heparinization should be considered In larger vessels, thrombectomy or local infusion of thrombolytic agents such as alteplase may be considered in consultation with vascular surgeons and interventional radiologists e15 During an ultrasound-guided pericardiocentesis, saline microbubble contrast (saline solution in a syringe that has been agitated) injected through the introducer needle demonstrates the appearance of contrast in the left ventricle The most appropriate next step is: A Alerting a cardiovascular operative team for emergency open pericardiotomy B Catheter placement, followed by high-resolution computed tomography coronary arteriography C Insertion of the guidewire D Removal of the needle Preferred response: D Rationale Several techniques are helpful to determine if blood obtained during pericardiocentesis is of cardiac or pericardial origin One technique involves injection of small amounts of saline microbubble contrast (saline solution in a syringe that has been agitated) through the introducer needle while imaging with echocardiography If contrast bubbles are seen in the heart, then the tip of the needle is intracardiac and should be removed If bubbles appear in the pericardial sac, then the needle is appropriately placed in the pericardium Chapter 15: Ultrasonography in the Pediatric Intensive Care Unit Which of the following statements is true regarding ultrasound guidance by intensivists for vascular access in children? A It is not useful for the placement of umbilical arterial or venous catheters B It should be performed using active (dynamic) ultrasound guidance, which is superior to physically marking the vessel location preprocedure (static guidance) C It should be performed with a transverse visualization of the vessel, as this is demonstrably superior to needle insertion in the longitudinal plane D It sufficiently increases safety in multiple studies of femoral and subclavian central venous catheter insertion to be considered the standard of care Preferred response: B Rationale Placement of central venous catheters using active ultrasound guidance has been demonstrated to be superior to marking position prior to the procedure Generalizable studies that demonstrate a significant safety benefit for subclavian vein central venous cannulation under ultrasound in children remain lacking Advantages of ultrasound use for arterial catheter and umbilical vein catheter placement have been described There have not been sufficient studies to determine whether transverse or longitudinal guidance approaches for vascular access are advantageous ... department (ED) The child was seen and discharged from that ED days ago This morning, her parents awoke to her loud breathing and called emergency medical services The emergency medical technicians... patient care However, economic terms are not discussed in this scenario Research is an important activity in generating new knowledge, but this scenario is concerned with the delivery of care to... tachypneic (respiratory rate, 55 breaths per minute) and undergoes intubation of the trachea within 30 minutes of PICU admission for respiratory failure Arterial blood gas reveals pH 7.2, Paco2