Non-invasive Monitoring of Oxygen and Carbon Dioxide Tension: Accuracy of Transcutaneous O2 and CO2 and Endtidal CO2

PURPOSE: To determine the concordance of transcutaneous CO2 (PtcCO2) versus arterial CO2 (PaCO2), end-tidal CO2 (PetCO2) versus PaCO2, and transcutaneous O2 (PtcO2) versus arterial O2 (PaCO2) among healthy adult volunteers, and to determine the normal values of the PtcCO2/PtcO2 and PtcO2/PaO2 that will be used as early signs of shock or as prognostic factors for critically ill patients. METHODS: We measured the PtcO2, PtcCO2, PetCO2, PaO2, and PaCO2 from 11 healthy volunteers while breathing room air or O2 at a flow rate of 6 L/min via nasal cannula. The PtcO2 and PtcCO2 were measured using a Radiometer's transcutaneous sensor that interfaced with the Solar 8000 patient monitor system. The PetCO2 was measured using a side stream capnometer that sampled air from a nasal catheter. The PaO2 and PaCO2 were measured from arterial blood samples. The concordances of the PtcCO2 versus the PaCO2, the PtcO2 versus the PaO2, and the PetCO2 versus the PaCO2 were analyzed using a Bland-Altman plot. We defined the normal values of the P(a-tc)CO2, PtcO2/PaO2, and PtcCO2/PtcO2. RESULTS: Twenty-two pairs of the PtcCO2 versus PaCO2, PtcO2 versus PaO2, and PetCO2 versus PaCO2 were obtained. The mean (+/-SD) values of the P(a-tc)CO2, P(atc) O2, and P(a-et)CO2 were 0(+/-2.2) mmHg, 35.4(+/-24.1) mmHg, and 1.4(+/-1.3) mmHg, respectively (p=0.947, p<0.001, and p<0.001 by paired t-test, respectively). The P(a-tc)CO2 and P(a-et)CO2 showed a high concordance of 95.5% within a range of +/-4 mmHg. The median (25~75%) values of the PtcCO2/PtcO2 and PtcO2/PaO2 at room air were 54.8%(46.8%~62.7%), respectively. CONCLUSION: The PtcCO2 and PetCO2 had a reliable concordance with the PaCO2. However, the PtcO2 was discordant with the PaO2 and this discordance was increased when inspiring O2. Therefore, the absolute values of the PtcO2 cannot be used as a surrogate measurement of the PaO2. However, because the O2 supply did not increase the PtcCO2, but rather the PtcO2, we can use the trend in the change in the PtcCO2/PtcO2 or PtcO2/PaO2 in shock patients.

The Effects of Urinary Trypsin Inhibitor on the Outcomes of Severe Sepsis and Septic Shock Patients

PURPOSE: We purposed to determine the effects of urinary typsin inhibitor (ulinastatin) on the outcomes of severe sepsis and septic shock patients. METHODS: This is a prospective case control study of severe sepsis and septic shock patients who visited emergency department of university hospital from January 2005 to June 2008. For study group, 100,000 U of ulinastatin was initially infused and then additional infusions of ulinastatin were determined by the mean arterial pressure. We compared the predicted mortality and the actual in-hospital mortality between the ulinastatin group and the control group. We also compared the improvement of the SOFA score according to time between the groups. RESULTS: There were 43 patients in the ulinastatin group and 126 patients in the control group. The predicted mortality and the actual mortality of the ulinastatin group were 31.2% and 18.6%, respectively. The predicted and actual mortalities of the control group were 33.1% and 27.0%, respectively. The improvement of the SOFA score for the ulinastatin group was 6.8+/-3.9 and 5.0+/-4.5 at 0 and 24 hours (p<0.001), 6.5+/-3.7 and 3.9+/-4.3 at 0 and 48 hours (p<0.001) and, 6.3+/-3.6 and 3.0+/-4.1 at 0 and 72 hours (p<0.001). For the control group, the change of the SOFA score was 4.9+/-2.9 and 5.8+/-4.1 at 0 and 24 hours (p=0.003), 5.0+/-2.8 and 5.1+/-4.2 at 0 and 48 hours (p=0.760) and, 4.8+/-2.7 and 4.34.1 at 0 and 72 hours (p=0.105). CONCLUSION: The ulinastatin group showed significantly lower mortality than the predicted mortality and the ulinastatin group's SOFA score was improved in the early hospital days.

Analysis of Patients with Acute Industrial Toxic Exposure at an Emergency Department in an Industrial Complex

PURPOSE: Surveys on poisoning usually involves intoxication rather than inhalation, skin contact, etc. Therefore, we examined the characteristics of patients who visited the emergency department in an industrial complex after acute industrial exposure to toxic materials. METHODS: Medical records of patients exposed to toxic materials in the work places from April, 2006, to March, 2008, were analyzed retrospectively. Inhalation patients due to fire were excluded. RESULTS: Subjects included 66 patients, with a mean age of 35.4+/-10.9 years, mostly men (91%). Toxicity occurred in 51 patients (77%) by contact, 15 patients (23%) by inhalation, and none by oral ingestion. For toxic materials, 10 patients were exposed to hydrofluoric acid, 8 to hydrochloric acid, 7 to sodium hydroxide, 7 to metals, and others. The face and hands were the most frequent exposure site by contact. Most exposures were caused by accidents, with 29 cases (42%) exposed because of carelessness or not wearing protective equipment. Most complaints were pain on exposure site, but 7 of the inhalation patients complained of dyspnea. The majority of patients with contact exposure were discharged after wound care or observation. After inhalation exposure, 1 patient died and 5 patients were admitted to the intensive care unit. CONCLUSION: Major causes of workplace exposure were not wearing protective equipment or carelessness. Although contact exposures are usually benign, cautious observation and management are required in patients with inhalation exposure.

Impact of Initial Helical Abdominal Computed Tomography on the Diagnosis of Hollow Viscus Injury and Blunt Abdominal Traumare

PURPOSE: This study was conducted to examine the clinical significance IV-contrasted helical abdomen computed tomography (CT) as a diagnostic screening tool to evaluate hollow viscus injury in blunt abdominal trauma patients. METHODS: This is a retrospective study encompassing 108 patients, presenting to Korea University Medical Center (KUMC) Emergency Department (ED) from January 2007 to December 2007, with an initial CT finding suggestive of intra-abdominal injury. An initial non-enhanced abdomen CT was taken, followed by an enhanced CT with intravenous contrast. Patients' demographic data, as well as the mechanisms of injury, were inquired upon and obtained, initial diagnosis, as dictated by specialized radiologists, were added to post-operational (post-OP) findings and to additional CT findings acquired during their hospital stays, and all were combined to arrive at final diagnosis. Initial CT findings were further compared with the final diagnosis, yielding values for sensitivity, specificity, and accuracy, as well as positive and negative predictive values. Patients were further divided into two groups, namely, those that underwent operational intervention and those that did not. The initial CT findings of each group were subsequently compared and analyzed. RESULTS: Initial CT scans revealed abnormal findings in a total of 212 cases - solid organ injuries being the most common finding, as was observed in 97 cases. Free fluid accumulation was evident in another 69 cases. Based on the CT findings, 77 cases (71.3%) were initially diagnosed as having a solid organ injury, 20 cases (18.5%) as having a combined (solid organ + hollow viscus) injury, and 11 cases (10.2%), as having an isolated hollow viscus injury. The final diagnosis however, were somewhat different, with only 67 cases (62.0%) attributed to solid organ injury, 31 cases (28.7%) to combined injury (solid + hollow), and 10 cases (9.3%) to hollow viscus injury. The sensitivity (CI 95%) of the initial helical CT in diagnosing hollow viscus injury was 75.6%, and its specificity was 100%. The accuracy in diagnosing hollow viscus injury was also meaningfully lower compared to that in diagnosis of solid organ injury. Among patients initially diagnosed with solid organ injuries, 10 patients (2 from follow-up CT and 8 from post-OP finding) turned out to have combined injuries. A total of 38 patients underwent an operation, and the proportion of initial CT findings suggesting free air, mesenteric hematoma or bowel wall thickening turned out to be significantly higher in the operation group. CONCLUSION: Abdominal CT was a meaningful screening test for hollow viscus injury, but the sensitivity of abdominal CT was significantly lower in detecting hollow viscus injury as compared to solid organ injury. This calls for special consideration and careful observation by the ED physicians when dealing with cases of blunt abdominal trauma.

Shock Index, Serum Lactate Level, and Arterial-End Tidal Carbon Dioxide Difference as Hospital Mortality Markers and Guidelines of Early Resuscitation in Hypovolemic Shock

PURPOSE: To determine whether differences in arterial and end-tidal carbon dioxide [P(a-et)CO2], shock index, and serum lactate levels are helpful for predicting the outcome of resuscitation in hypovolemic shock patients in the emergency department. METHODS: A prospective study of end-tidal carbon dioxide (EtCO2)-derived variables and patient outcomes in hypovolemic shock was conducted in the emergency department of a university hospital from January 2005 to February 2006. A total of fifty-eight hypovolemic shock patients over 20 years old were included. During resuscitation, patients received volume replacement including blood transfusions, as well as vasopressor or inotropic therapy if needed. RESULTS: Twenty-one patients died in the hospital. At the time of admission (hour 0) and after resuscitation (hour 4), there were no differences related to age, respiration and heart rate, CVP, arterial blood gases, or EtCO2 between survivors and non-survivors. Non-survivors had significantly higher shock index scores, serum lactate levels, and P(a-et) CO2 than the survivors. The Receiver operator characteristic (ROC) curves at hour 4 hour for P(a-et)CO2 were as effective for predicting mortality as were the shock index and serum lactate levels. Shock index > 1.0, P(a-et)CO2 > 4 mmHg, and serum lactate > 5.0 mmol/L after resuscitation were all associated with a high early mortality rate (p=0.074, 0.001, 0.000, respectively). CONCLUSION: P(a-et)CO2, shock index, and serum lactate levels are predictive of in-hospital mortality and may be useful as guidelines in the resuscitation of hypovolemic shock patients in the emergency department.