18 A 25‐year‐old man was brought to the emergency room intoxicated after he was found at the bottom of a staircase. His GCS was 7 and he was intubated for airway protection. Upon intubation, he was found to have particulate matter and bile staining in his airway. A nasogastric tube was placed and chest x‐ray confirms the position of the nasogastric and endotracheal tubes, but shows infiltrates in the right lower lobe. What is the most appropriate therapy for his aspiration?FluconazolePiperacillin/tazobactamVancomycinPiperacillin/tazobactam + vancomycinNo antimicrobial therapyAspiration is defined as the inhalation of oropharyngeal or gastric contents into the larynx and lower respiratory tract. Aspiration pneumonitis (Mendelson's syndrome) is a chemical injury caused by the inhalation of sterile gastric contents, whereas aspiration pneumonia is an infectious process caused by the inhalation of oropharyngeal secretions that are colonized by pathogenic bacteria. Aspiration of gastric contents results in a chemical injury of the tracheobronchial tree and pulmonary parenchyma, causing an intense parenchymal inflammatory reaction. The prophylactic use of antibiotics in patients in whom aspiration is suspected or witnessed is not recommended. Similarly, the use of antibiotics shortly after aspiration in patients in whom a fever, leukocytosis, or a pulmonary infiltrate develops is discouraged, since the antibiotic may select for more resistant organisms in patients with an uncomplicated chemical pneumonitis. With the presence of particulate matter in the airway, strong consideration for performing diagnostic/therapeutic bronchoscopy is warranted.Answer: EMarik PE . Aspiration pneumonitis and aspiration pneumonia. N Engl J Med. 2001; 344(9):665–671. doi: https://doi.org/10.1056/NEJM200103013440908. PMID: 11228282.
19 A 65‐year‐old man is recovering in the surgical ICU following subtotal colectomy and end ileostomy for severe clostridium difficile infection. He is receiving enteral nutrition via a nasogastric tube. He is having persistent gastric residuals of 250 mL.Which of the following is the best next step in management?Discontinue enteral feeds for 2 hours and restart enteral nutrition at 50% of prior rate.Discontinue enteral feeds indefinitely and initiate TPN.Continue current rate of enteral feeding.Change to an elemental tube feed.Start promotility agents.Malnutrition is a major problem in the ICU. Critically ill patients are in a catabolic state requiring increased caloric demand. Trophic feeds in patients in septic shock have been demonstrated to lower mechanical ventilation days and length of stay. Enteral nutrition is frequently held for procedures, operations, and imaging studies. Multiple studies have shown that gastric residual volumes are unnecessary and only further contribute to malnutrition (choice A). TPN is not indicated with a functioning enteric tract (choice B). Elemental feeds are more costly and may help with absorption in patients with malabsorptive disease. They would have no effect on gastric motility (choice D). Promotility agents may decrease gastric residuals but do not affect mortality (choice E).Answer: CReignier J, Mercier E, Le Gouge A, et al. Effect of not monitoring residual gastric volume on risk of ventilator‐associated pneumonia in adults receiving mechanical ventilation and early enteral feeding: a randomized controlled trial. JAMA. 2013; 309(3):249–256.Patel JJ, Kozeniecki M, Biesboer A, et al. Early trophic enteral nutrition is associated with improved outcomes in mechanically ventilated patients with septic shock: a retrospective review. J Intensive Care Med. 2016; 31(7):471–477.McClave SA, Martindale RG, Vanek VW, et al. Guidelines for the provision and assessment of nutrition support therapy in the adult critically Ill patient: Society of Critical Care Medicine (SCCM) and American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.). JPEN J Parenter Enteral Nutr. 2009; 33(3):277–316.
20 A 31‐year‐old woman is 32 weeks pregnant and works at a local grocery store at the deli counter. She presents to the hospital with high fevers, nuchal rigidity, and altered mental status. She is admitted to the ICU with the diagnosis of meningitis. CSF analysis is pending.What is the empiric antibiotic regimen of choice for this patient?Vancomycin and piperacillin/tazobactamVancomycin, ceftriaxone, and penicillin GVancomycin, ciprofloxacin, and ampicillinGentamicin, metronidazole, and amoxicillinVancomycin and cefotaximeStreptococcus pneumoniae followed by Neisseria meningitidis are the most common causative organisms for bacterial meningitis for the age group 16–50. Vancomycin and a third‐generation cephalosporin should be used as empiric antibiotics (choice E). In pregnancy, there is also a risk of Listeria monocytogenes meningitis. Listeria is a facultative anaerobic gram‐positive bacillus that is often transmitted via soft cheeses and smoked meats. The patient is at risk for this due to her occupation. Listeria is not susceptible to cephalosporins or vancomycin. A penicillin is necessary for adequate empiric coverage (choice B). Gentamicin and ciprofloxacin are pregnancy class D drugs and should be avoided during pregnancy (choice D).Answer: BAllerberger F, Wagner M. Listeriosis: a resurgent foodborne infection. Clin Microbiol Infect 2010; 16(1):16–23.Van de Beek D, de Gans J, Tunkel AR, Wijdicks EF . Community‐acquired bacterial meningitis in adults. N Engl J Med. 2006; 354(1):44–53.
6 Hemodynamic and Respiratory Monitoring
Jared Sheppard, MD, Christopher S. Nelson, MD, and Stephen L. Barnes, MD
Division of Acute Care Surgery, Department of Surgery, University of Missouri, Columbia, MO, USA
1 A 19‐year‐old man suffering a gunshot wound (GSW) to the right chest is diaphoretic, hypotensive, tachycardic, and has decreased lung sounds in the right chest. He groans and localizes to painful stimuli. After placement of a thoracostomy tube, 1 L of dark blood is evacuated. Initial ABG shows:pH ‐ 7.29pCO2 ‐ 36Bicarbonate: 17Base excess: ‐8.6Lactic acid: 5.3Which of the above values is most concerning for shock in this patient?pHPCO2BicarbonateBase excessLactic acidThe patient above clearly has significant blood loss from his GSW, such that he is in physiologic shock as a result of inadequate tissue perfusion. This can cause decreased GCS, and is consistent with his hypotension and tachycardia. Lactic acid is normally produced in excess by about 20 mmol/kg/day, which enters the bloodstream. It is then metabolized mostly by the liver and the kidney. Some tissues can use lactate as a substrate and oxidize it to carbon dioxide (CO2) and water, but only the liver and kidney have the necessary enzymes to utilize lactate for the process of gluconeogenesis. In general, elevated lactate can be the result of increased production, decreased clearance, or both. The tissues which normally produce excess lactic acid include the skin, red cells, brain tissue, muscle, and the gastrointestinal (GI) tract. During heavy exercise, it is the skeletal muscles which produce the most excess circulating lactate, which normalizes in the absence of impaired hepatic metabolism. Inadequate perfusion causes inadequate oxygen delivery to the tissue beds, which prevents normal aerobic respiration on the cellular level. As a result, anaerobic respiration begins, which results in net 2ATP per molecule of glucose (compared with 32 net ATP with aerobic respiration), and produces lactate as a byproduct. This elevation in lactate is responsible for the changes in pH and subsequent base deficit exhibited by this patient. Shock and severe lactic acidosis (pH less than 7.2) are often comorbid, and this carries a mortality rate of about 50%. Survival is rare for severe lactic acidosis with shock when the pH had fallen under 7.0. The base deficit is also an indicator of severe shock; however,