Acute Care Surgery: Part 1

From Trauma, Critical Care, and Acute Care Surgery presented by the Trauma and Critical Care Foundation

Educational Objectives

The purpose of this program is to improve outcomes of acute care surgery. After hearing and assimilating this program, the clinician will be better able to:

1.   Describe the consequences of poor pain control and new approaches to pain management.

2.   Manage trauma in the obese patient.

3.   Recognize appropriate applications of ligation vs primary repair of great vein injuries.

4.   Treat postsurgical infections within the context of current concerns about drug-resistant organisms.

5.   Discuss suggestions for improving triage for emergency helicopter transport.

Faculty Disclosure

In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and members of the planning committee to disclose relevant financial relationships within the past 12 months that might create any personal conflicts of in­terest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial interest. For this program, the faculty and planning committee reported nothing to disclose.

Acknowledgments

This program was recorded at Trauma, Critical Care, and Acute Care Surgery 2009, held April 5-8, 2009, in Las Vegas, NV, and sponsored by the Trauma and Critical Care Foundation. The Audio-Digest Foundation thanks the speakers and the Trauma and Critical Care Foundation for their cooperation in the production of this program.

Tell Me How Much it Hurts: Pain Management

M. Margaret Knudson, MD, Professor, Department of Surgery, University of California, San Francisco, School of Medicine

Consequences of poor pain control: rise in catecholamines, leading to hypertension, greater cardiac oxygen demand, and increased risk for myocardial infarction; blood cortisol levels also rise (may impede glucose control); hyperglycemia as­sociated with increased risk for infection; increased incidence of deep venous thrombosis (DVT) and pulmonary emboli (PE); prolonged hospital stays, with associated increases in costs

Pain assessment: Joint Commission first to require assessment of pain with every check of vital signs (pain considered “fifth vital sign”); validated 4-point scale  —  used in intensive care unit (ICU); based on patient’s facial expressions, body movements, muscle tension, and ventilatory compliance or ability to speak; in pediatrics  —  available algorithms all based on facial expression, movement, and ability to be consoled

Overmedication: between 2000 and 2004, cause of death in 32 to 46 patients of >4000 studied; times of greatest risk  —  after transfer from ICU to floor and during radiologic procedures

New approaches to pain control: transcutaneous electrical nerve stimulation (TENS)  —  traditionally used to control chronic pain; now being tested for post-thoracotomy pain; associated with improved pulmonary function and decreased opiate requirements; ambulatory drug delivery systems (eg, On-Q Pain Relief System)  —  can deliver local anesthesia di­rectly to wound; used to relieve pain of rib fractures; virtual reality systems  —  can distract pediatric burn patients from pain of dressing changes or physical therapy; associated with reduced doses of opiates; acupuncture and acupressure  —  good control of pain related to fractures; used in ambulance

Trauma in the Obese Patient

Carlos V.R. Brown, MD, Associate Professor of Surgery, University of Texas, Medical Branch, Austin

Pathophysiology of obesity: cardiovascular  —  increased total blood volume, cardiac output (due to increased stroke vol­ume), and oxygen consumption; left ventricular function impaired due to longstanding hypertension; pulmonary  —increased work of breathing; sleep apnea and obesity hypoventilation syndrome common; metabolic syndrome  —  hyperglycemia, proin­flammatory state, and prothrombotic state complicate trauma care

Trauma prevention: 30% of obese and 55% of severely obese people do not wear automobile seatbelts; seatbelt use by obese accident victims associated with increased risk for injury to abdominal wall, skin, and soft tissue, but fewer intra-abdominal injuries and lower mortality

Patterns of injury: obese people sustain fewer head injuries but more lower-extremity fractures than leaner patients; risk for abdominal injuries lower in overweight patients (body mass index [BMI] 25-30), but risk for thoracic and abdomi­nal injuries rises when BMI >30

Respiratory problems: exacerbated by trauma; use noninvasive ventilation for rescue soon after admission or at time of extubation

Continuous positive airway pressure (CPAP): constant pressure (no inspiratory support); not indicated for hypoxia or obesity hypoventilation

Noninvasive positive pressure ventilation (NPPV): available in pressure and volume modes; bilevel positive airway pres­sure (BiPAP) most common pressure mode; provides inspiratory support; volume control positive pressure ventilation rarer, more expensive, and more difficult to use; NPPV compatible with standard ventilators

Delivery of noninvasive ventilation: options include full-face mask (most effective but least well-tolerated), nasal mask, or nasal prongs

Indications: hypoxic respiratory failure, postextubation respiratory failure, and obesity hypoventilation syndrome; contraindications  —  cardiac or respiratory arrest; multisystem organ failure; facial trauma; upper airway obstruc­tion; neurologic problems that prevent patient from cooperating; facial trauma and aspiration 2 most common com­plications of NPPV

Nutrition and pharmacology: calculations based on various measurements; total body weight  —  measure on patient’s ar­rival; ideal body weight  —  separate formulas used for men and women; adjusted body weight  —  ideal body weight plus factor based on difference between total body weight and ideal body weight; speaker uses 25% of difference as added factor

Response to injury: obese patients  —  have higher protein turnover and deficient production of protein, which result in more severe postinjury malnutrition; oxidize fat less efficiently than leaner patients; burn protein as primary fuel; formulas for calculating nutritional requirements  —  unreliable in obese population; indirect calorimetry most reliable method; average requirement 21 kcal/kg per day total body weight; hypocaloric feeds (17-18 kcal/kg per day) acceptable; protein require­ment 2 g/kg of ideal body weight per day

Pharmacology: base doses of opioids and sedatives on ideal body weight; base dose of succinylcholine on total body weight; depending on class, antibiotics dosed according to total or adjusted body weight; anticoagulation  —  use ad­justed body weight for therapeutic dosing; prophylactic dosing unpredictable (twice daily dosing possibly superior for obese patients); measurement of anti-factor Xa level advised before administration of low molecular weight heparin  

Great Vein Injury: Repair or Ligation?

Gregory J. Jerkovitch, MD, Professor of Surgery, University of Washington School of Medicine, and Chief of Trauma Services, Harborview Medical Center, Seattle, WA

Main goal: to stop bleeding

Organ injury scaling (OIS) system: grade 1  —  non-named branches of abdominal venous structures; grade 2  —  splenic or inferior mesenteric vein (IMV), or branches of superior mesenteric vein (SMV); grade 3  —  trunk of SMV, any section of renal vein, or infrarenal inferior vena cava (IVC); lethal in 50% of cases; grade 4  —  suprarenal IVC; grade 5  —  portal vein, retrohepatic vena cava, and hepatic veins

Grade 3 injuries: in retrospective review of 51 patients with grades 3 to 5 injuries, survival rate »40%; 30 (59%) veins ligated; 16 veins underwent primary repair; 10 patients died before SMV management; 45% of patients died (due to bleeding) while in operating room; overall surgical survival rate 47%; survival for isolated SMV repair 55%; lethality increased when combination of veins involved; OIS slightly higher in patients undergoing ligation (compared to repair); ligation also associated with more injuries, including other major vascular injuries (eg, mesenteric artery, aorta); consequently, mortality higher among patients undergoing ligation; take-home message  —  overall survival rate from SMV injuries 50%, based on data from several studies; conclusions  —mesenteric venous injuries lethal; mortality correlates with overall in­jury severity; higher survival rates reported in patients who undergo primary repair rather than ligation, most likely due to fewer and/or less severe associated injuries in former

Injuries to infrarenal IVC: most common intra-abdominal venous injury; overall survival rate »75%; repair — done in transverse fashion with running 4-0 or 5-0 prolene sutures; approach injuries on back of vena cava through anterior opening, with first knot outside of wall, and run sutures toward other end, leaving only one knot inside; time permit­ting, consider patch repair (minimizes hourglass shape) using ovarian vein, inferior mesenteric vein branch, or polytet­rafluoroethylene (PTFE); patency of repairs £86%; ligation  —  advisable if exsanguination likely without intervention; usually well tolerated; postoperative management key; keep patient’s legs elevated; anticipate edema and venous ex­pansion; wrap legs in compression stockings and monitor for compartment syndrome; perform fasciotomy if neces­sary; custom-fitted support hose recommended for long-term maintenance

Renal vein injuries: nephrectomy required if ligated, unless injury on proximal left side (ie, drainage good; kidney may be salvageable); associated survival rates good

Grade 4: suprarenal IVC  —  ligate only to prevent exsanguination; associated with bilateral renal infarction and kidney loss; options include PTFE or Dacron conduit

Grade 5 injuries: in largest study of portal vein trauma (56 patients), most injuries occurred in most accessible portions of vein; controlled with proximal Pringle maneuver and distal venous clamping; overall mortality rate 57%; 33 patients un­derwent primary repair (mortality rate 42%); 10% underwent ligation (mortality rate 90%); difference most likely due to better control of bleeding in patients undergoing primary repair; control methods include direct manual pressure, Pringle maneuver with occluding clamps, and wide Kocher maneuver; study of data from period between 1958 and 1988 show best results achieved when ligation performed as early as possible after determining that lateral repair not feasible; conse­quences include 50% decline in circulating venous volume (patient will need aggressive resuscitation); other complica­tions include mesenteric edema and thickening of bowel wall (usually resolves within 72 hr)

Conclusions: hemorrhage control should be primary tenet; if patient hemodynamically stable, primary repair preferred; if repair impossible, ligate early; plan second-look surgery, especially for mesenteric vein injuries; postoperative man­agement strategies key to long-term success

Bugs and Drugs for the Critical Care Surgeon

Philip S. Barie, MD, Professor of Surgery and Public Health, Weil Cornell Medical College, New York, NY

Staphylococcus aureus: current North American resistance rates to oxacillin or methicillin 50% to 63% (has recently pla­teaued); prevalence of community-acquired methicillin-resistant S aureus (MRSA) in skin and skin structures much lower in northeastern United States than rest of nation; most outbreaks in colder climates; incidence of nosocomial and community-acquired infections increasing since 2000; nosocomial strain associated with infections of respiratory and urinary tracts, as well as skin and soft tissue; skin and soft tissue infections predominate in community-acquired strain

Vancomycin-resistant enterococci (VRE): resurging with greater use of oral vancomycin to treat Clostridium difficile infec­tions; about two-thirds of Enterococcus faecium isolates now resistant; <5% of Enterococcus faecalis strains resistant; VRE affects mostly profoundly debilitated hosts; major risk factors include hospitalization and previous stay in ICU

Highly drug-resistant pathogens: ESKAPE (E faecium, S aureus, Klebsiella, Acinetobacter baumannii, Pseuomonas ae­ruginosa, and Enterobacter) mnemonic

Clinical implications: bacteremia due to resistant organism associated with much higher mortality than that with sensitive strains (eg, VRE and MRSA double mortality, drug-resistant Klebsiella increases mortality by 60%); prevalence of or­ganisms producing carbapenemases growing

International patterns: resistance prevalent wherever antibiotic use “rampant and poorly controlled”; problem global due to international travel; Study for Monitoring Antimicrobial Resistance Trends (SMART) looked at drug susceptibilities in Escherichia coli isolates with and without extended-spectrum b-lactamase (ESBL), and found susceptibilities signifi­cantly reduced in those with enzyme; more than one-third of community-acquired E coli isolates resistant to ciprofloxa­cin and levofloxacin; similar patterns seen in Klebsiella and Enterobacter species producing ESBL; >200 types of ESBL now recognized; list growing annually

Pseudomonas: has several virulence mechanisms; may have capability of detecting vulnerable host and increasing viru­lence; primary resistance mechanism amp-c b-lactamase

Klebsiella pneumoniae carbapenemase (KPC): now in 30 states; most prevalent in northeastern United States; spreading across south and Midwest; found worldwide; need to establish reliable laboratory tests for detection; test all patients with serious infections taking carbapenems; eradication will require infection control measures, laboratory support, and surveillance

Metallo-b-lactamases: now seen in Europe; help bacteria obtain metals (eg, zinc) required for growth and to overcome antibiotics; relevant in Enterobacter and Pseudomonas

Drugs under development: ceftobiprole  —  close to approval; telavancin  —  lipoglycopeptide; in phase III trials; may be ap­proved for skin and soft tissue infections; only drug in pipeline with novel mechanism of action (necessary to combat re­sistant organisms)

Helicopter Transport of Patients

Sydney J. Vail, MD, Medical Director, Trauma Services, Maricopa Medical Center, Department of Surgery, Di­vision of Burns, Trauma, and Surgical Critical Care, and Medical Director, Tactical Medicine Program, Ari­zona Department of Health, Phoenix

Risks: injury or death of patient, pilot, and crew; property damage if helicopter crashes or makes forced landing; fatal accidents associated with helicopter emergency medical services (EMS) exceed those associated with road EMS by factor of 13.5; fatality rates exceed those of road EMS by factor of 34; Virginia data  —  only state looking at medical outcomes of helicopter transport; shown to be useful in improving outcomes if within 30-mi radius; if between 30 and 60 mi, less clear; if >60 mi, ground transport faster and more efficient

Appropriate helicopter use: value greatest “when integrated into well-organized ambulance service and emergency sys­tem, with good triage and close medical supervision”

National Transportation Safety Board (NTSB) data: no fatal accidents reported in Canada, despite >230,000 hr flown; attributed largely to strong proactive flight risk assessments, including those for patient and crew

Possible benefits: delivery of advanced care (must weigh costs against benefits); support for ground EMS crew; faster transport time (controversial; found to speed direct transport to level I centers); greater transport flexibility; ability to per­form unusual or ad hoc activities (flight crews highly trained)

Proposed improvements: develop information systems and protocols to identify best candidates for transport (currently, 25%-30% of patients arriving by helicopter discharged within 24 hr); establish regional, state, or local patient criteria, based on in­formation in trauma databases; optimal overtriage rate 20% to 30%; perform objective critical analysis and risk assessment for every flight and ground transport lasting >30 min (if time-sensitive injuries involved); improve training of EMS person­nel

Suggested Reading

Asensio JA et al: Superior mesenteric venous injuries: to ligate or repair remains the question. J Trauma 62:668, 2007; Bledsoe BE et al: Helicopter scene transport of trauma patients with nonlife-threatening injuries: a meta-analysis. J Trauma 60:1257, 2006; Boucher HW et al: Bad bugs, no drugs, no ESKAPE! An update from the Infectious Diseases Society of America. Clin Infect Dis 49:992, 2009; Buckman RF et al: Portal vein injuries. Surg Clin North Am 81:1449, 2001; Fin­kelstein EA et al: The relationship between obesity and injuries among U.S. adults. Am J Health Promot 21:460, 2007; Jurkovitch Gregory J et al: Portal Triad Injuries. J Trauma Inj Inf Crit Care 39:426, 1995; Lucas CE et al: Kindness kills: the negative impact of pain as the fifh vital sign. J Am Coll Surg 205:101, 2007; McVey J et al: Air versus ground transport of the major trauma patient: a natural experiment. Prehosp Emerg Care 14:45, 2010; Mitchell AD et al: Air ver­sus ground transport of major trauma patients to a tertiary trauma centre: a province-wide comparison using TRISS analy­sis. Can J Surg 50:129, 2007; Ringburg AN et al: Cost-effectiveness and quality-of-life analysis of physician-staffed helicopter emergency medical services. Br J Surg 96:1365, 2009; Viano DC et al: Crash injury risks for obese occupants using a matched-pair analysis. Traffic Inj Prev 9:59, 2008; Zarzaur BL, Marshall SW: Motor vehicle crashes obesity and seat belt use: a deadly combination? J Trauma 64:412, 2008.