Article

Is tissue oxygen saturation related with complete blood parameters in ED patients?

Correspondence / American Journal of Emergency Medicine 32 (2014) 12781293 1283

The change in ideal compression rate into “at least 100/min” has given us one question, “Which number should we pick up among the many numbers from 100 to 120?” In the response to above question, this study shows that informing a specific rate between 100/min and 120/min would be better than informing using range for maintaining high quality of compression when we apply the metronome for audio guidance under 2010 guidelines. There have been no studies determining the appropriate metronome guide rate to ensure that chest compression is performed at a rate of at least 100/min, as specified in the 2010 guidelines. In the present study, only 25.93% of participants could maintain a compression rate between 100/min and 120/min with a metronome speed of 100/min.

The quality of rate of chest compression by untrained bystander could be influenced by different methods indicating 100/min to 120/min on metronome. We suggest that untrained bystanders could perform chest compression in accordance with the recommendations when the audio guidance was given as a certain number between 100/min and 120/min rather than as a range.

Figure. Differences according to compression rates at 3 different metronome speeds. There was significant difference among groups in rate of chest compression by Kruskal-Wallis test (P b .001). In intergroup analysis by Mann-Whitney test, P was .004 between group 1 (120/min) and group 2 (110/min), b.001 between group 2 and group 3 (100/min), and

b.001 between group 1 and group 3. The gray area indicated the range of rate of chest compression from 100/min to 120/min.

Hands-only CPR and randomly divided into 3 groups. Each group performed simulation with mannequins with different 3 ways indicating at least 100/min: the metronome rates were 120/min, 110/min, and 100/min in groups 1, 2, and 3, respectively. During a 2-minute simulated CPR, the mean depth and rate of chest compression were recorded.

We found no significant differences among the 3 groups in sex or age. In all groups, the mean depth of chest compression was less than 5 cm. The mean rates of chest compression were 113.44 +- 12.35/min in group 1,

109.37 +- 2.73/min in group 2, and 128.11 +- 16.22/min in group 3 (Figure). There was a significant difference among groups (P b .001). The mean rate of chest compression of group 1 (120/min) and group 3 (100/min) was higher than that of group 2 (110/min). However, the proportions of compressions between 100 and 120/min were 100.00% (24/24) in group 2, 70.00% (19/24) in group 1, and 25.93% (7/27) in group 3.

To use metronome in D-CPR, the metronome should be set a definite rate. In the current guideline, the rate of metronome should be selected from 100/min to 120/min. Therefore, we selected 3 different rates of metronome; 100/min, 110/min, and 120/min. We hypothesized that the actual speed of chest compression performed by untrained bystander is influenced by how participants perceive the speed of chest compression by different settings of metronome and instruction. Participants in group 3 with the metronome speed of 100/min would have understood that they should compress the chest faster than the rate indicated by the metronome. Consequently, the results reflected various rates of chest compression greater than 100/min. With the metronome rate set to 120/min, the participants in group 1 attempted to perform chest compression slower than exemplified by the metronome guide. Although the mean rate of chest compression did not exceed 120/min, rates varied widely to lower than 100/min among participants (Figure). The reason why these results have emerged would be that untrained participants among each group had a different understanding of the appropriate rate of chest compression when the dispatcher informed that the rate of chest compression should be between 100/min and 120/min. Under these circumstances, untrained bystanders may find it difficult to maintain correct rate despite audio guidance. However, in group 2 (110/min), the metronome was set to a speed of 110/min, and participants performed chest compression at the rate of the metronome. In results, the proportion of compressions between

Dong Hoon Lee, MD, PhD Department of Emergency Medicine, College of Medicine Chungang University, Chung-Ang University Hospital 224-1 Heoukseok-dong, Dongjak-gu, Seoul, Korea

E-mail address: [email protected]

Chan Woong Kim, MD, PhD Department of Emergency Medicine, College of Medicine Chungang University, Chung-Ang University Hospital 224-1 Heoukseok-dong, Dongjak-gu, Seoul, Korea

E-mail address: [email protected]

Sung Eun Kim, MD, PhD Department of Emergency Medicine, College of Medicine Chungang University, Chung-Ang University Hospital 224-1 Heoukseok-dong, Dongjak-gu, Seoul, Korea

E-mail address: [email protected] http://dx.doi.org/10.1016/j.ajem.2014.07.009

References

  1. Berg RA, Hemphill R, Abella BS, et al. Part 5: adult basic life support: 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation 2010;122:S685-705.
  2. Kern KB, Stickney RE, Gallison L, et al. Metronome improves compression and ventilation rates during CPR on a manikin in a randomized trial. Resuscitation 2010;81:206-10.
  3. Chung TN, Kim SW, You JS, et al. The specific effect of metronome guidance on the quality of one-person cardiopulmonary resuscitation and rescuer fatigue. J Emerg Med 2012;43:1049-54.
  4. Paal P, Pircher I, Baur T, et al. Mobile phone-assisted basic life support augmented with a metronome. J Emerg Med 2012;43:472-7.
  5. Chung TN, Kim SW, You JS, et al. A higher chest compression rate may be necessary for metronome-guided cardiopulmonary resuscitation. Am J Emerg Med 2012;30:226-30.

    Is tissue oxygen saturation related with complete Blood parameters in ED patients??

    To the Editor,

    complete blood count is an easy analysis that is usually overlooked by clinicians, and parameters of CBC may provide to make a prediction about the patient’s clinical status, related with the illness [1]. mean platelet volume (MPV) is an indicator of the size

    100/min and 120/min was 100% when the metronome was set to a

    rate of 110/min (gray area in Figure).

    ? Author (s) declare that they have no conflict of interest.

    1284 Correspondence / American Journal of Emergency Medicine 32 (2014) 12781293

    Table

    Correlations between StO2 and age, WBC, Hct, MCV, Plt, MPV, and RDW according to sex

    Age

    WBC

    Hb

    Hct

    MCV

    Plt

    MPV

    RDW

    StO2 correlation for females

    P: .048

    P: .171

    P: .894

    P: .245

    P: .264

    P: .057

    P: .058

    P: .599

    r: 0.244

    r: -0.17

    r:-0.017

    r: 0.146

    r:-0.141

    r: 0.237

    r:-0.236

    r: 0.066

    StO2 correlation for males

    P: .639

    P: .479

    P: .337

    P: .639

    P: .123

    P: .011

    P: .207

    P: .864

    r: 0.060

    r: 0.090

    r: -0.122

    r: 0.060

    r: 0.195

    r: 0.317

    r: -0.16

    r: -0.02

    StO2 correlation for total

    P: .639

    P: .699

    P: .269

    P: .032

    P: .944

    P: .155

    P: .016

    P: .240

    r: 0.06

    r: 0.034

    r: 0.098

    r: 0.189

    r: -0.006

    r: 0.126

    r:-0.211

    r: 0.104

    Abbreviation: Hb, hemoglobin (level).

    distribution of platelets (Plts). The MPV is directly correlated with the rate of Plt production [2].

    Near-infrared spectroscopy allows Noninvasive measurement of tissue oxygen saturation (StO2) [3,4], and literature has reported that it can be useful in determining the severity of hemorrhagic shock [5], fluid resuscitation [6], septic shock [7], and predicting multiple-organ dysfunction syndrome [8]. But there is a lack of data on its use in emergency practice [9].

    To the best of our knowledge, no research has been peformed to date for evaluation of the relationship of StO2 levels and CBC parameters in the emergency department (ED). The aim of the present study was to determine the relationship between StO2 levels and CBC parameters of ED patients.

    Approval of the human study committee of our medical faculty was provided for this study. The participants/relatives were informed and gave their informed consent. We examined 130 patients who were admitted to our ED and underwent laboratory evaluation. Age, sex, and CBC parameters including white blood cell count , hemoglobin level, hematocrit (Hct), mean corpuscular volume (MCV), red cell distribution width (RDW), Plt, and MPV levels of the patients were noted. For the StO2 level measurement, an InSpectra device was placed to the right thenar muscle for 10 seconds, and means of the first, fifth, and 10th second values were noted at the time of admission. In our study, we measured thenar muscle StO2 via wide-gap second-derivative near-infrared spectroscopy (InSpectra; Hutchinson Technology, Hutch- inson, MN). Cardiopulmonary arrest patients and patients less than age 18 years were excluded from the study.

    The normal distribution and homogeneity of each parameter were tested using the Shapiro-Wilk test and the Kolmogorov-Smirnov test. Age and StO2 values did not suit the normal distribution. A Mann- Whitney U test was used for differences between and among the 2 groups. A spearman correlation test was used for correlation analysis. In all tests, the significance level was P b .05. SPSS (Chicago, IL) software 20.0 was used for analysis.

    In our study, 66 (50.8%) female and 66 (48.2%) male for total of 130 patients were included. Mean age of our study group was 47.75 +-

    18.91 (min,18; max, 80). The mean StO2 level of females was 80.52 +-

    5.89 (min, 67; max, 92), and mean StO2 level of males was 78.50 +- 6.53 (min, 62; max, 93). Mean StO2 values of the sexes were significantly different (P = .02). Tissue oxygen saturation levels were correlated with Hct (P = .032, r = .189) and MPV(P = .016, r = -.211) levels. Detailed correlations between StO2 and age, WBC, Hct, MCV, Plt, MPV, and RDW according to sex are given in the Table.

    Tissue oxygen saturation values are correlated with Hct and MPV levels. Tissue oxygen saturation level measurement may be helpful in predicting the Hct and MPV values of the ED patients.

    Sadiye Yolcu, MD

    Bozok University Department of Emergency Medicine

    Yozgat, Turkey E-mail address: [email protected]

    http://dx.doi.org/10.1016/j.ajem.2014.07.003

    References

    Sandhaus LM, Meyer P. How useful are CBC and reticulocyte reports to clinicians? Am J Clin Pathol 2002;118(5):787-93.

  6. Threatte GA. Usefulness of the mean platelet volume. Clin Lab Med 1993;13(4): 937-50.
  7. Cohn SM. Near-infrared spectroscopy: potential clinical benefits in surgery. J Am Coll Surg 2007;205(2):322-32.
  8. Creteur J. Muscle StO2 in critically ill patients. Curr Opin Crit Care 2008;14(3):361-6.
  9. Beilman GJ, Blondet JJ. Near-infrared spectroscopy-derived tissue oxygen saturation in battlefield injuries: a case series report. World J Emerg Surg 2009; 4:25.
  10. George ME, Beilman GJ, Mulier KE, et al. Noninvasive tissue oxygen saturation measurements identify supply dependency. J Surg Res 2010;160 (1):40-6.
  11. Rodriguez A, Lisboa T, Martin-Loeches I, et al. Mortality and regional oxygen saturation index in septic shock patients: a pilot study. J Trauma 2011;70(5): 1145-52.
  12. Cohn SM, Nathens AB, Moore FA, et al. Tissue oxygen saturation predicts the development of organ dysfunction during traumatic shock resuscitation. J Trauma 2007;62(5):44-50 [Discussion].
  13. Yolcu S, Erdur B. Use of Tissue oxygenation (StO2) monitor in the ED. Am J Emerg Med 2014. http://dx.doi.org/10.1016/j.ajem.2014.04.037.

    Association of physician risk tolerance with ED CT use for isolated dizziness/vertigo patients?,??

    Dizziness/vertigo is one of the most common principal complaints in the emergency department (ED) [1], accounting for 2.5% of all ED presentations [2]. Although the most common causes of dizziness/vertigo are benign, potential life-threatening stroke especially cerebellar or brain stem infarction should be considered in the differential diagnosis because isolated dizziness without other concurrent neurologic symptoms can be the sole presentation of these conditions [3-5]. Noncontrast brain computed tomography (CT) provides the necessary information for emergency management of most patients with suspected stroke and is the most commonly used brain imaging method in EDs [6]. The proportion of Cerebrovascular events in patients aged 44 years and older with dizziness as the main presenting symptom is as low as 0.7% [5], and the diagnostic yield of brain CT is only 2.2% [7]. However, an early definitive diagnosis is often difficult to make in patients with vague dizziness symptoms. Considering the consequences of misdiagnosis including potential critical disease and litigious risk, emergency physicians (EPs) may lower the testing threshold for brain imaging in managing these low-probability, high-morbidity situations.

    Previous studies have demonstrated that risk tolerance, perception of uncertainty, and malpractice fear were associated with physician practice variation and may drive physicians to practice risk-averse behavior [8-13]. The most risk averse and most malpractice concern quartiles of EPs were associated with higher admission rates and greater use of cardiac markers in patients with chest pain [9,10,12]. Personal risk-taking

    ? Prior presentations: The abstract of this manuscript has been presented as a poster in Australasian College for Emergency Medicine 30th Annual Scientific Meeting, 2013/11/24-28, Adelaide, Australia.

    ?? Funding sources/disclosures: No.

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