Outcomes with the use of recombinant human erythropoietin in critically ill burn patients.

Recent data demonstrate a possible mortality benefit in traumatically injured patients when given subcutaneous recombinant human erythropoietin (rhEPO). The purpose of this report is to examine the effect of rhEPO on mortality and transfusion in burn patients. We conducted a review of burn patients (greater than 30% total body surface area, intensive care unit [ICU] days greater than 15) treated with 40,000 u rhEPO over an 18-month period (January 2007 to July 2008). Matched historical controls were identified and a contemporaneous cohort of subjects not administered rhEPO was used for comparison (NrhEPO). Mortality, transfusions, ICU and hospital length of stay were assessed. A total of 105 patients were treated (25 rhEPO, 53 historical control group, 27 NrhEPO). Hospital transfusions (mean 13,704 +/- mL vs. 13,308 +/- mL; P = 0.42) and mortality (29.6 vs. 32.0%; P = 0.64) were similar. NrhEPO required more blood transfusions (13,308 +/- mL vs. 6827 +/- mL; P = 0.004). No difference in mortality for the rhEPO and NrhEPO (32.0 vs. 22.2%; P = 0.43) was found. Thromboembolic complications were similar in all three groups. No effect was seen for rhEPO treatment on mortality or blood transfusion requirements in the severely burned.

Correlation between capnography and arterial carbon dioxide before, during, and after severe chest injury in swine.

The relationship between end-tidal carbon dioxide (EtCO(2)) and arterial carbon dioxide (PaCO(2))-if better defined-could facilitate the difficult task of ventilation in prehospital trauma patients. We aimed to study the PaCO(2)-EtCO(2) relationship before, during, and after chest trauma, hemorrhage, and resuscitation in swine. Twenty-four swine were intubated, anesthetized, and monitored in an animal intensive care unit during three phases: phase 1 (day 1, healthy animals); phase 2 (day 2, injury), which consisted of blunt chest trauma, hemorrhage, and resuscitation; and phase 3 (day 2, after injury). "Respiratory maneuvers" (changes in respiratory rate and tidal volume [TV], intended to vary the PaCO(2) over a range of 25 to 85 mmHg, were performed during phases 1 and 3. End-tidal CO(2) and PaCO(2) were recorded after each respiratory maneuver and analyzed using linear regression. During phase 1, PaCO(2) and EtCO(2) were strongly correlated (r(2) = 0.97, P < 0.01). During phase 2, animals developed decreased oxygenation (PaO(2):FiO(2) [fraction of inspired oxygen] ratio <200) and hypotension (mean arterial pressure, 20-50 mmHg); the PaCO(2)-EtCO(2) relationship deteriorated (r(2) = 0.25, P < 0.0001). During phase 3, oxygenation, hemodynamics, and the PaCO(2)-EtCO(2) relationship recovered (r(2) = 0.92, P < 0.01). End-tidal CO(2) closely correlates to PaCO(2) in healthy animals and after injury/resuscitation across a wide range of respiratory rates and tidal volumes. Once oxygenation and hemodynamics are restored, EtCO(2) can be used to predict PaCO(2) following chest trauma/hemorrhage and should be considered for patient monitoring. This work demonstrated that EtCO(2) alone can reliably be used to estimate PaCO(2) in uninjured subjects and in those subjects who have been resuscitated from severe injury. Immediately after blunt chest injury, the correlation between EtCO(2) and PaCO(2) is temporarily unstable. Under these circumstances (with abnormal oxygenation and/or hemodynamics), greater caution and other monitoring tools may be required.

Hyperspectral imaging: a new approach to the diagnosis of hemorrhagic shock.

BACKGROUND: Skin color changes and mottling are frequently described signs of hemorrhagic shock (HEM). Based on this, we developed a noninvasive, noncontact hyperspectral imaging system (HSI), which quantifies and depicts the surface tissue saturation of oxygen (SHSIO2) for each pixel in a region of interest (ROI). Our purpose was to assess HSI in a porcine HEM model. We hypothesized that HEM would cause decreases in SHSIO2 of the skin. METHODS: The HyperMed HSI system employs a spectral separator to vary the wavelength of light admitted to a digital camera. During image acquisition, a "hypercube" of images, each at a separate wavelength, is generated (at 5-nm intervals, from 500 to 600 nm). Then, the visible light spectrum for each pixel in the hypercube is compared by linear regression to standard spectra for oxyhemoglobin (OxyHb) and deoxyhemoglobin (DeoxyHb). The resulting fit coefficients for OxyHb and DeoxyHb are used to calculate SHSIO2 values for each pixel in the ROI. The mean values for OxyHb, DeoxyHb, and SHSIO2 across the ROI are calculated. Grayscale SHSIO2 pictures of the ROI are also generated, in which the brightness of each pixel is proportional to its value. Seventeen pigs, 36.4 +/- 0.11 kg, underwent standard preparation, and were maintained on ketamine and isoflurane. Normothermia was maintained (37 degrees C to 39 degrees C). The hemorrhage group (HEM, n = 9) underwent three blood withdrawals, each 10 mL/kg, with 15 minutes between withdrawals. After the third withdrawal, animals were resuscitated with lactated Ringer's and then shed blood. The control group (CTRL, n = 8) received intravenous fluids at 100 mL/h. HSI images were obtained of the inner hindlimb throughout. RESULTS: All HEM animals showed linear decreases in both mean SHSIO2 and OxyHb values with blood loss, which were reversed by resuscitation. These changes were evident on the grayscale SHSIO2 pictures, but not to the naked eye, and paralleled those of invasively obtained arterial base excess and mixed venous oxygen saturation. CONCLUSIONS: HSI is a promising noninvasive and noncontact tool for quantifying changes in skin oxygenation during HEM and resuscitation.