Design and Evaluation of a Wireless Electrocardiogram Monitor in an Operating Room: A Pilot Study.

BACKGROUND: Wired electrocardiogram monitors are an important component of current perioperative monitoring. Wireless monitoring units could help reduce the number of cables attached to patients and thus improve anesthesia ergonomics and patient management. However, there is concern that electromagnetic interference generated by electrosurgical units may prevent effective wireless signals in the operating room. To evaluate the extent of this problem, we developed a Bluetooth electrocardiogram prototype monitor and compared its electrocardiogram traces to those captured with a standard wired electrocardiogram monitor in our operating room. METHODS: Bluetooth electrocardiogram and standard electrocardiogram traces captured from 10 patients undergoing surgical procedures that required use of an electrosurgical unit were compared by analysis of the durations of the P wave, QRS complex, and T wave and the position of the ST segment from the isoelectric line. The impact of the electrosurgical units on the Bluetooth electrocardiogram and S-electrocardiogram recordings was also assessed. RESULTS: There were no clinically relevant differences in P wave, QRS complex, or T-wave durations (0.006, 0.004, and 0.017 seconds, respectively) between Bluetooth electrocardiogram and standard electrocardiogram or in the position of the ST segment from the isoelectric line (0.02 mV). Mean differences were near zero, and Bland-Altman limits of agreement for individual differences were narrow (-0.035 to 0.047, -0.03 to 0.038, and -0.112 to 0.078 seconds for P wave, QRS complex, and T-wave durations, respectively, and -0.13 to 0.17 mV for ST segment position). Electrosurgical units use electrically disrupted Bluetooth electrocardiogram and standard electrocardiogram signals, but there was no electromagnetic interference effect on the Bluetooth electrocardiogram signals. CONCLUSIONS: Wireless electrocardiogram using Bluetooth can be reliably used in the operating room. The electrosurgical unit induces electric rather than electromagnetic artifacts, thus affecting wired and wireless electrocardiogram in a similar fashion.

Determination of the learning curve for ultrasound-guided jugular central venous catheter placement.

PURPOSE: Use of ultrasound (US) when introducing central venous catheters (CVC) may improve success rates, reduce the number of needle punctures, and decrease complication rates, but has been hampered by supposed difficulty in learning how to perform the technique. This study describes the learning curve for US-guided jugular CVC placement after a training program. METHODS: After an initial slide presentation and a video, intensivists who had not previously used US for CVC placement were evaluated qualitatively for US set up (score S1) and technical skills (score S2). Quantitative measures included durations of different components of the procedure (T1, time from entry of the US into the patient's room to sterile dressing of the intensivist; T2, time needed for sterile drapes, venous line preparation, and sterile sheath placement; T3, time from skin puncture to venous flashback; T4, time from guide insertion to dressing; T(tot), total duration of the procedure); number of skin punctures; and a difficulty score allocated by the intensivist. RESULTS: We performed 150 evaluations of 30 intensivists: 50% had no prior experience of CVC placement and 50% no prior US experience. Maximal S1 and S2 scores were obtained with the fourth and eighth placement procedures, respectively. T1 and T2 did not change with ongoing training (5 and 8 min, respectively), but T3 and T4 decreased, from 5 min (first procedure) to less than 1 min (seventh procedure), and from 10 min (first procedure) to 7 min (sixth procedure), respectively. T(tot) decreased from 34 to 21 min at the eighth procedure. The number of skin punctures and the difficulty score decreased rapidly with the number of evaluations. CONCLUSIONS: Our study demonstrates that skills in US-guided CVC placement can easily be acquired with training.

[Severe imported Falciparum malaria treated with artesunate]. / Paludisme grave d'importation à Plasmodium falciparum traité par artésunate.

Falciparum malaria is a potentially deadly infectious disease, imposing a sure and fast biologic diagnosis, an early and efficient treatment. We report a case of severe imported Falciparium malaria who received artesunate, and we rewiew the different diagnostic methods of malaria as well as the clinico-biological characteristics of severe malaria. Recent data concerning malaria treatment are presented, as a pharmacokinetic study leaded during this case.

The accuracy of noninvasive hemoglobin measurement by multiwavelength pulse oximetry after cardiac surgery.

BACKGROUND: In March 2008, a new multiwavelength pulse oximeter, the Radical 7 (Rad7; Masimo Corp., Irvine, CA), was developed that offers noninvasive measurement of hemoglobin concentration. Accuracy has been established in healthy adults and some surgical patients, but not in cardiac surgery intensive care patients, a group at high risk of postoperative bleeding events and anemia in whom early diagnosis could improve management. METHODS: In this prospective, observational study conducted in a cardiovascular intensive care unit, we compared hemoglobin concentrations shown by the Rad7 with arterial hemoglobin concentrations determined by an automated hematology analyzer, XE-2100 (Roche, Neuilly sur Seine, France). Two software versions of Rad7 (V 7.3.0.1 [42 points of comparison in 14 patients] and the updated V 7.3.1.1 [61 points of comparison in 27 patients]) were studied during two 1-week periods. Bias, defined as the difference between the 2 methods (Masimo SpHb-XE-2100 laboratory hemoglobin), was calculated. A negative bias indicated that the Masimo underestimated hemoglobin compared with the laboratory analyzer. Correlation between the perfusion index given by Rad7 and the hemoglobin bias was also studied. RESULTS: Correlations between Rad7 and XE-2100 were weak for both software versions (R2=0.11 for V 7.3.0.1 and R2=0.27 for V 7.3.1.1). Mean bias was -1.3 g/dL for V 7.3.0.1 and -1.7 g/dL for V 7.3.1.1, with wide 95% prediction intervals for the bias (respectively, -4.6 to 2.1 g/dL and -5.7 to 2.3 g/dL). The absolute hemoglobin bias tended to increase when the perfusion index decreased. For the V 7.3.0.1 software, the average absolute bias was 1.9 g/dL for perfusion index<2 and 0.8 g/dL for perfusion index>2 (P=0.03). For V 7.3.1.1, the mean absolute bias was 2.1 g/dL when the perfusion index was <2, and 1.6 g/dL when the perfusion index was >2 (P=0.26). CONCLUSIONS: Our study demonstrates poor correlation between hemoglobin measured noninvasively by multiwavelength pulse oximetry and a laboratory hematology analyzer. The difference was greater when the pulse oximetry perfusion index was low, as may occur in shock, hypothermia, or vasoconstriction patients. The multiwavelength pulse oximetry is not sufficiently accurate for clinical use in a cardiovascular intensive care unit.

The reproducibility of Stewart parameters for acid-base diagnosis using two central laboratory analyzers.

BACKGROUND: Acid-base derangements can be interpreted using the Stewart-Fencl approach, which includes calculation of the apparent strong ion difference (SID(app)), the effective SID (SID(eff)), and the strong ion gap (SIG). These calculations require the measurement of several variables. We hypothesized that the SID and SIG calculated by different analyzers would not be reproducible because of variability in the measured values. METHODS: In this prospective observational study conducted in a biochemistry laboratory, we analyzed 179 routine blood samples from consecutive patients over a 3-mo period using two automated blood chemistry analyzers, the LX20 (Beckman) and the Modular (Roche). Measured and calculated parameters from the two analyzers were compared. RESULTS: Although the correlation between measured values was satisfactory, there were large differences in the limits of agreement for calculated values (SID(app): 9.6 mEq/L, SID(eff): 6.4 mEq/L, and SIG: 11.7 mEq/L) and a weak correlation (SID(app): r(2) = 0.54 and SIG: r(2) = 0.12) between the analyzers. CONCLUSIONS: The results of the Stewart-Fencl approach for interpretation of acid-base status can vary according to the analyzer used. These differences may have important clinical and research implications..

Management of cardiac arrest caused by coronary artery spasm: epinephrine/adrenaline versus nitrates.

BACKGROUND: Cardiopulmonary resuscitation guidelines imply the use of epinephrine/adrenaline during cardiopulmonary arrest. However, in cardiac arrest situations resulting from coronary artery spasm (CAS), the use of epinephrine/adrenaline could be deleterious. METHODS AND RESULTS: A 49-year-old patient underwent an emergency coronarography with an attempt to stent the coronary arteries. Radiologic imaging revealed a positive methylergonovine maleate (Methergine, Novartis Pharmaceuticals, East Hanover, NJ) test, with subocclusive CAS in several coronary vessels leading to electromechanical dissociation. Cardiopulmonary resuscitation was performed, and intracoronary boluses of isosorbide dinitrate were given to treat CAS. Epinephrine/adrenaline was not administered during resuscitation. Spontaneous circulation was obtained after cardioversion for ventricular fibrillation, and the patient progressively regained consciousness. CONCLUSION: Resuscitation guidelines do not specify the use of trinitrate derivatives in cardiac arrest situations caused by CAS. The pros and cons of the use of nitrates and epinephrine/adrenaline during cardiac arrest caused by CAS are analyzed in this case report.

Time course of hemoglobin concentrations in nonbleeding intensive care unit patients.

OBJECTIVES: To evaluate the time course of hemoglobin concentrations in nonbleeding intensive care unit patients. DESIGN: Prospective, observational study. SETTING: Multidisciplinary (medicosurgical) department of intensive care. PATIENTS: Ninety-one patients with no evidence of recent or active blood loss, no history of hematologic disease or chronic renal failure, and no need for extracorporeal epuration techniques. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Data collection included primary diagnoses, Acute Physiology and Chronic Health Evaluation II and sepsis-related organ failure assessment scores, signs of sepsis, 24-hr fluid balance, and hemoglobin concentrations. For the entire intensive care unit stay, the fall in hemoglobin concentrations (calculated from the mean of individual slopes of hemoglobin concentrations over time) averaged 0.52 +/- 0.69 g/dL/day. For the 33 patients who stayed in the intensive care unit for >3 days, this decline was larger for the first 3 days than for subsequent days (0.66 +/- 0.84 g/dL/day vs. 0.12 +/- 0.29 g/dL/day; p<.01). After the third intensive care unit day, the change in hemoglobin concentrations was inversely related to the severity of the disease, as reflected by the Acute Physiology and Chronic Health Evaluation II and the sepsis-related organ failure assessment scores. Hemoglobin concentrations decreased by 0.44 +/- 0.70 g/dL/day in the nonseptic and 0.68 +/- 0.66 g/dL/day in the septic patients (p =.13). After the third intensive care unit day, hemoglobin concentrations continued to decrease in the septic patients but not in the nonseptic patients (-0.29 +/- 0.19 vs. 0.006 +/- 0.3 g/dL/day; p=.0016). The fall in hemoglobin concentrations was not significantly related to the fluid balance. The volume of blood drawn daily for laboratory studies was 40.3 +/- 15.4 mL: 49.0 +/- 11.3 mL in the septic patients and 36.7 +/- 14.9 mL in the nonseptic patients (p =.04). CONCLUSIONS: Hemoglobin concentrations typically decline by >0.5 g/dL/day during the first days of intensive care unit stay in nonbleeding patients. Beyond the third day, hemoglobin concentrations can remain relatively constant in nonseptic patients but continue to decrease in septic patients, as well as patients with high sepsis-related organ failure assessment or Acute Physiology and Chronic Health Evaluation II scores. These observations may help in the interpretation of hemoglobin concentrations in critically ill patients.

The Multiple Organ Dysfunction Score (MODS) versus the Sequential Organ Failure Assessment (SOFA) score in outcome prediction.

OBJECTIVE: To compare outcome prediction using the Multiple Organ Dysfunction Score (MODS) and the Sequential Organ Failure Assessment (SOFA), two of the systems most commonly used to evaluate organ dysfunction in the intensive care unit (ICU). DESIGN: Prospective, observational study. SETTING: Thirty-one-bed, university hospital ICU. PATIENTS AND PARTICIPANTS: Nine hundred forty-nine ICU patients. MEASUREMENTS AND RESULTS: The MODS and the SOFA score were calculated on admission and every 48 h until ICU discharge. The Acute Physiology and Chronic Health Evaluation (APACHE) II score was calculated on admission. Areas under receiver operating characteristic (AUROC) curves were used to compare initial, 48 h, 96 h, maximum and final scores. Of the 949 patients, 277 died (mortality rate 29.1%). Shock was observed in 329 patients (mortality rate 55.3%). There were no significant differences between the two scores in terms of mortality prediction. Outcome prediction of the APACHE II score was similar to the initial MODS and SOFA score in all patients, and slightly worse in patients with shock. Using the scores' cardiovascular components (CV), outcome prediction was better for the SOFA score at all time intervals (initial AUROC SOFA CV 0.750 vs MODS CV 0.694, p<0.01; 48 h AUROC SOFA CV 0.732 vs MODS CV 0.675, p<0.01; and final AUROC SOFA CV 0.781 vs MODS CV 0.674, p<0.01). The same tendency was observed in patients with shock. There were no significant differences in outcome prediction for the other five organ systems. CONCLUSIONS: MODS and SOFA are reliable outcome predictors. Cardiovascular dysfunction is better related to outcome with the SOFA score than with the MODS.