Gina Luckianow

A physicochemical approach to acid-base balance in critically ill trauma patients minimizes errors and reduces inappropriate plasma volume expansion

BACKGROUND This study assesses if a physicochemical (PC) approach to acid-base balance improves the accuracy of acid-base diagnosis, and reduces inappropriate fluid loading. METHODS Hundred consecutive patients with trauma admitted to a surgical intensive care unit at a level I trauma center were prospectively analyzed. Demographics, acid-base data and diagnoses, and interventions were collected. Patients were cared for by one physician using a PC approach, or four using conventional (CONV) acid-base balance techniques. The diagnoses and interventions made by CONV physicians were reviewed by the PC physician for accuracy and appropriateness using PC techniques. Data are mean +/- SD or percents; p values reflect PC evaluation of CONV analysis. RESULTS There were 50 PC patients and 50 CONV. There were no differences in age (p = 0.13), injury severity score (p = 0.21), number of operations (p = 0.87), transfusions (p = 0.87), or survival (p = 0.15). CONV missed 12 diagnoses of metabolic acidosis (p = 0.03), 10 of hyperchloremic metabolic acidosis (p = 0.003), 11 metabolic alkalosis (p = 0.02), and 19 tertiary disorders (p < 0.001). CONV missed 38 diagnoses of increased unmeasured ions (p < 0.001). PC normalized their acid-base balance sooner than CONV (3.3 days +/- 3.4 days vs. 8.3 days +/- 7.4 days, p < 0.01). CONCLUSIONS A PC approach improves acid-base diagnosis accuracy. CONV often miss acidosis (particularly those because of hyperchloremia), alkalosis, and tertiary disorders. Inappropriate volume loading follows in the wake of misinterpretation of increased base deficit using CONV and is avoided using PC. PC-directed therapy normalizes acid-base balance more rapidly than CONV.

Uncovering System Errors Using a Rapid Response Team: Cross-coverage Caught in the Crossfire

BACKGROUND Because of the 80-hour work week, extensive service cross-coverage creates great potential for patient care errors. These patient care emergencies are increasingly managed using a rapid response team (RRT) to reduce patient morbidity. We examine the proximate causes of a surgical RRT activation. We hypothesize that most RRTs would occur during cross-coverage hours and be preventable or potentially preventable. METHODS All surgical RRTs more than a 15-month period were captured using a nursing database and the note from the staffing intensivist/fellow. RRTs were reviewed for appropriateness (pre-existing criteria) and proximate cause. Proximate causes were further classified as patient disease, team error, nursing error, or system error as well as preventable, potentially preventable, or nonpreventable. RESULTS Of 98 RRT activations, complete data were available for 82 (84%); 100% met activation criteria; and 76 (93%) occurred between 2100 and 0600. Seventy-six patients were 48 hours to 72 hours postoperative; six had nonoperatively managed injuries. The most common reason for activation was impending respiratory failure and acute volume overload (n = 72; 88%). RRT therapies included diuretics (n = 72), antiarrhythmics (n = 48), oxygen (n = 82), and bronchodilators (n = 36); only 2 received blood component therapy. Seventy-eight patients (95%) were transferred to higher level of care (61, surgical intensive care unit; 17, SSDU). Only 46% of patients required intubation. Performance improvement review identified 90% of physician related RRTs as preventable/potentially preventable because of errors in judgment or omission. Four RRTs because of patient disease were unpreventable. Two potentially preventable errors were each ascribed to RN or system concerns. CONCLUSION RRT activations principally result from team-based errors of omission, more often occur between 2100 and 0600, and are more often preventable or potentially preventable. Careful attention to fluid balance and medications for comorbid diseases would reduce RRT needs.

Abdominal compartment syndrome: risk factors, diagnosis, and current therapy.

Abdominal compartment syndromes manifestations are difficult to definitively detect on physical examination alone. Therefore, objective criteria have been articulated that aid the bedside clinician in detecting intra-abdominal hypertension as well as the abdominal compartment syndrome to initiate prompt and potentially life-saving intervention. At-risk patient populations should be routinely monitored and tiered interventions should be undertaken as a team approach to management.

Lessons learned from airway pressure release ventilation.

BACKGROUND: The aim of this article is to review a single institutions experience with airway pressure release ventilation (APRV) with respect to safety, complications, and efficacy at correcting hypercarbia and hypoxemia. METHODS: Patients transitioned from either volume- or pressure-targeted ventilation to APRV in a university hospital surgical intensive care unit were retrospectively reviewed. Patients whose ventilator strategy started with APRV were excluded. Abstracted data included age, sex, diagnosis, ventilation parameters, indication for altering the ventilator strategy, laboratory values, and ventilator-associated complications. Data before and after transitioning to APRV were compared using a two-tailed unpaired t test or &khgr;2 test as appropriate; significance assumed for p ⩽ 0.05. RESULTS: Patient mix (n = 38) was 43% trauma, 32% sepsis, 8% cardiac surgery, 12% vascular surgery, and 5% other. Transitioning to APRV was undertaken most often for hypoxemia (88%) and less frequently for hypercarbia (12%). The mean time to correct hypoxemia (SAO2 >92%) was 7 minutes ± 4 minutes, while the mean time to correct PCO2 (PCO2 ⩽40 mm Hg) was 42 minutes ± 7 minutes. The mean time to maximal CO2 clearance was 66 minutes ± 12 minutes. The mean minute ventilation decreased on APRV by 3.3 L/min ± 0.9 L/min but achieved superior CO2 clearance and oxygenation. The mean time to FIO2 ⩽0.6 was 5.2 hours ± 0.9 hours. Four of the 38 patients developed a pneumothorax. Ninety-seven percent of patients on APRV who were transported out of the intensive care unit using bag-valve ventilation (with appropriate positive end-expiratory pressure valve settings) with Phigh ≥20 cm H2O developed hypoxemia within 5 minutes. Hundred percent of patients with a Phigh ⩽20 cm H2O were safely hand ventilated during transport without developing hypoxemia. CONCLUSIONS: APRV is a safe mode of ventilation for hypoxemic or hypercarbic respiratory failure. Improvements in PO2 and PCO2 are achieved at lower minute ventilations than with volume- or pressure-targeted modes. LEVEL OF EVIDENCE: III.

When the ICU is the operating room.

BACKGROUND The surgical intensive care unit (SICU) is increasingly used as a surrogate operating room (OR). This study seeks to characterize a Level I trauma center’s operative undertakings in the SICU versus OR for trauma and emergency general surgery patients. METHODS Operative and ICU databases were queried for all operative procedures as a function of procedure type (CPT code) and location (OR, ICU) from August 2002 through June 2009. Mode of ventilation, type of anesthesia used, and adverse outcomes were recorded. Data were divided into 2002–2006 versus 2007–2009 because of MD staffing and service structure changes. Time frames were compared via Student’s t-test or &khgr;2 as appropriate; significance for p < 0.05 (*) versus 2002–2006. RESULTS Trauma service–admitted patient volume increased from 2002–2003 (n = 1,293) to 2006–2007 (n = 1,577) and again in 2008–2009 (n = 1,825). Emergency general surgery total operative cases increased from 2002–2003 (n = 246) to 2005–2006 (n = 468). Case volume further increased in 2006–2007 (n = 767*), 2007–2008 (n = 1,071*), and 2008–2009 (n = 875*) compared with 2002–2003 or 2005–2006. Relaparotomy and temporary abdominal closure procedures were significantly increased in 2007–2008 (n = 109*) and 2008–2009 (n = 128*) versus 2002–2006 (n = 6) and 2006–2007 (n = 10). ICU cases were 11.5% of total cases (OR + ICU) spanning 2002–2006 and significantly increased to 24.3%* in 2007–2008 and 36%* in 2008–2009. Advanced ventilation was used in 15% of ICU cases in 2002–2003 and significantly increased to 40% in 2006–2007 and 78%* in 2008–2009. Neuromuscular blockade was rare; most cases (93.9%) were performed under deep sedation. CONCLUSION Our ICU is increasingly used for surgical procedures traditionally reserved for the OR. Advanced ventilation management may influence the choice of operative location. The ICU may be safely used as an operative location for the critically ill and injured. LEVEL OF EVIDENCE Epidemiologic study, level III.

Bridging the gap between training and advanced practice provider critical care competency.

ABSTRACTGiven the meteoric rise in physician assistants and nurse practitioners in critical care units across the United States, identifying successful paradigms with which to train these clinicians is critical to help meet current and future demands. We describe an apprenticeship model of training that is deployable in any ICU including curriculum, didactic and procedural training, as well as 3- and 6-month benchmarks that embraces dedicated intensivist mentorship.

Ventilator gas delivery wave form substantially impacts plateau pressure and peak-to-plateau pressure gradient determination.

BACKGROUND To determine whether plateau pressure (Pplat) measurement is lowered and peak airway pressure (Pawpeak)–to–Plat gradient is increased by measurement on a decelerating compared with square gas delivery wave form. METHODS Prospective before and after study of mechanically ventilated injured and critically ill patients in an adult surgical intensive care unit. Pplat, Pawpeak, and Pawpeak-to-Pplat gradient were measured on decelerating and square gas delivery wave forms. RESULTS Pplat and other routine ventilator parameters were measured in 82 (47 trauma, 35 emergency general surgery) consecutive convenience sampled adult intensive care unit patients on decelerating and then square gas delivery wave forms. Peak gas flow was fixed at 40 L/min; all other parameters (rate, tidal volume, positive end-expiratory pressure) were held constant. All patients were managed on assist control volume cycled ventilation using fentanyl and midazolam or propofol; no neuromuscular blockade was used. Patients with Pawpeak more than 35 cm H2O were excluded. Comparing decelerating with square gas delivery, mean Pawpeak was lower (25.1 ± 2.3 cm H2O vs. 33.1 ± 2.1 cm H2O; p < 0.0001) and mean Pplat was lower (21.3 ± 1.9 cm H2O vs. 24.8 ± 2.5 cm H2O; p < 0.0001), resulting in a decreased Pawpeak-to-Pplat gradient (3.8 ± 2.1 vs. 8.3 ± 2.3; p < 0.0001). CONCLUSION Changing from a decelerating to a square gas delivery wave form significantly increases Pplat and Pawpeak, thereby increasing the Pawpeak-to-Pplat gradient. This increase may prompt unwarranted therapy aimed at reducing the gradient to its normal value of 4 cm H2O pressure or less. Conversely, patients with a high Pawpeak on a square wave form may benefit from transitioning to a decelerating wave form before changing ventilation parameters. LEVEL OF EVIDENCE Diagnostic study, level III.

Confounders in the Diagnosis of Pulmonary Edema in Surgical Patients

A host of clinical conditions may be accompanied by an increase in extravascular lung water (EVLW), and may have a cardiogenic or non-cardiogenic etiology [1, 2]. Regardless of the inciting cause, the increased tissue water (and electrolyte) component is often identifiable on clinical examination and supported by confirmatory radiographic analysis [3–5]. When the edema component is severe, clinical signs and symptoms are readily apparent and include, but are not limited to, an increased work of breathing (including accessory muscle use), rales, hypoxemia, hypercarbia, respiratory (and often metabolic) acidosis, as well as frothy, thin sputum that can be aspirated after placing an endotracheal tube for mechanical ventilatory support [6]. Medical patients are often diagnosed with pulmonary edema during an exacerbation of a pre-existing comorbidity such as myocardial ischemia, chronic obstructive pulmonary disease (COPD), acute-on-chronic renal insufficiency, as well as after early goal-directed therapy-based resuscitation for severe pneumonia.

Diagnostic Imaging Review

›CASE A 62-year-old woman presented to the emergency department complaining of abdominal pain. After undergoing CT, she was diagnosed with a perforated duodenal ulcer. An urgent laparoscopic Graham patch procedure was performed to repair the defect. The patient’s initial postoperative course was uneventful. However, melena associated with acute blood-loss anemia on postoperative day 4 prompted a tagged RBC scan, which identified ileal hemorrhage. The patient was transferred to the ICU for plasma volume expansion guided by central venous pressure monitoring. A triple-lumen catheter (TLC) was placed using the left subclavian position. The subclavian vein was accessed on the first attempt, and catheter insertion, utilizing the Seldinger technique, was accomplished without complication. A portable anteroposterior chest radiograph was obtained to confirm placement (Figure 1). What did the radiograph show?