Monitoring Tissue Oxygenation during Resuscitation of Major Burns

Venkatesh, Balasubramanian; Meacher, Roseanne; Müller, Michael; Morgan, Thomas J.; Fraser, John F.

doi:10.1097/00005373-200103000-00013

Cited by 67 publications

(18 citation statements)

References 54 publications

(47 reference statements)

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“…Moreover, there have been reports that monitoring oxygenation can provide useful clinical information for evaluating the effects of chemotherapy and radiotherapy on tumors 14 and monitoring healing of wounds. 15 Currently, pulse oximetry remains the most widely used clinical technique but it is limited by poor spatial resolution and the inability to monitor vessels situated deep into the body due to increased light scattering. 16 There is no imaging modality currently capable of detecting and characterizing the presence of RBC aggregation as well as assessing the oxygenation state of blood.…”

Section: Assessing Rbc Aggregation and Oxygenationmentioning

confidence: 99%

Photoacoustic ultrasound spectroscopy for assessing red blood cell aggregation and oxygenation

2012

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Abstract. Red blood cell (RBC) aggregation and oxygenation are important markers for a variety of blood disorders. No current technique is capable of simultaneously measuring aggregation/oxygenation levels noninvasively. We propose using photoacoustic ultrasound spectroscopy (PAUS) for assessing both phenomena. This technique relies on frequency-domain analysis of the PA signals by extracting parameters such as the ultrasound spectral slope and the midband fit. To investigate the effect of hematocrit, aggregation, and oxygenation levels on PAUS parameters, a Monte Carlo-based theoretical model and an experimental protocol using porcine RBCs were developed. The samples were illuminated at 750 and 1064 nm and changes in the PAUS parameters were compared to the oxygendependent optical absorption coefficients to assess the oxygenation level. Good agreement between the theoretical and experimental spectral parameters was obtained for the spectral slope of the nonaggregated spectra (∼0.3 dB∕MHz). The experimental midband fit increased by ∼5 dB for the largest aggregate size. Based on the analysis of the PA signals, the oxygen saturation level of the most aggregated sample was >20% greater than the nonaggregated sample. The results provide a framework for using PA signals' spectroscopic parameters for monitoring the aggregation and oxygenation levels of RBCs.

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Section: Assessing Rbc Aggregation and Oxygenationmentioning

confidence: 99%

Photoacoustic ultrasound spectroscopy for assessing red blood cell aggregation and oxygenation

2012

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“…Therefore, an erythrocyte was approximated as a fluid sphere in this work with a volume of 87 μm 3 and radius, a ¼ 2.75 μm. The density and speed of sound in a cell were taken as ρ s ¼ 1092 kg∕m 3 and υ s ¼ 1639 m∕s, respectively. 30 The acoustical properties for the surrounding medium (saline water) were taken as ρ f ¼ 1005 kg∕m 3 and v f ¼ 1498 m∕s, respectively.…”

Section: Physical Properties Of a Red Blood Cellmentioning

confidence: 99%

“…The density and speed of sound in a cell were taken as ρ s ¼ 1092 kg∕m 3 and υ s ¼ 1639 m∕s, respectively. 30 The acoustical properties for the surrounding medium (saline water) were taken as ρ f ¼ 1005 kg∕m 3 and v f ¼ 1498 m∕s, respectively. 30 The numerical values of the thermal properties for a RBC were chosen as β ¼ 1 K −1 and C P ¼ 1 J Kg K −1 .…”

Section: Physical Properties Of a Red Blood Cellmentioning

confidence: 99%

“…The blood oxygenation level (derived from hemoglobin concentration) is crucially important for understanding brain hemodynamics in response to sensory stimulation. 1 Moreover, it can provide useful clinical information for numerous medical applications such as evaluating the effects of chemotherapy and radiotherapy on tumors, 2 monitoring the healing of wounds, 3 and studying gene expression. 4 Of all the techniques that have been employed to measure blood oxygenation in vivo, pulse oxymetry remains the most commonly used clinical technique.…”

Section: Introductionmentioning

confidence: 99%

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Validity of a theoretical model to examine blood oxygenation dependent optoacoustics

et al. 2012

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Abstract. A theoretical model investigating the dependence of optoacoustic (OA) signal on blood oxygen saturation (SO 2 ) is discussed. The derivations for the nonbandlimited and bandlimited OA signals from many red blood cells (RBCs) are presented. The OA field generated by many RBCs was obtained by summing the OA field emitted by each RBC approximated as a fluid sphere. A Monte Carlo technique was employed generating the spatial organizations of RBCs in two-dimensional. The RBCs were assumed to have the same SO 2 level in a simulated configuration. The fractional number of oxyhemoglobin molecules, confined in a cell, determined the cellular SO 2 and also defined the blood SO 2 . For the nonbandlimited case, the OA signal amplitude decreased and increased linearly with blood SO 2 when illuminated by 700 and 1000 nm radiations, respectively. The power spectra exhibited similar trends over the entire frequency range (MHz to GHz). For the bandlimited case, three acoustic receivers with 2, 10, and 50 MHz as the center frequencies were considered. The linear variations of the OA amplitude with blood SO 2 were also observed for each receiver at those laser sources. The good agreement between simulated and published experimental results validates the model qualitatively.

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“…Preliminary reports regarding regional CO 2 measurement in sensible microvascular beds, as manifestation of hypoperfusion, are promising [71][72][73]. Measurement of oxygen tension or saturation in certain tissues has permitted the identification of occult hypoperfusion in animal studies and in some limited clinical experiences published [71,[74][75][76][77][78]. Unfortunately, these methods have not been fully evaluated, and none of them has reached widespread use.…”

Section: Endpoints For the Resuscitationmentioning

confidence: 99%

Critical Care Issues in the Early Management of Severe Trauma

García

2006

Surgical Clinics of North America

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Violent trauma and road traffic injuries kill more than 2.5 million people in the world every year. It has been calculated by the World Health Organization that in 2002 there occurred 1.6 million violent deaths [1] and 1.2 million deaths from traffic injury [2], for a combined mortality of 48 deaths per 100,000 population per year.Most trauma deaths occur at the scene or in the first hour after trauma, with a proportion from 34% to 50% occurring in hospitals [3]. These deaths could be prevented by optimization of trauma care. Preventability of trauma deaths has been reported as high as 76% [4] and as low as 1% in mature trauma systems [5,6].Prehospitalization procedures, elapsed time to hospital arrival are, of course, vital to the whole trauma scenario, but errors made in the in-hospital phase of care are responsible for one third to two thirds of the reported by different authors [7,8]. Of these, intensive care unit (ICU) errors are among the most frequent and significant. Errors in the ICU management of trauma patients were studied by Duke and colleagues [9]. They reported 165 ICU trauma deaths. Two hundred fifty-eight errors occurred in 81 patients (52%), and 134 of them contributed to death in 52 patients (34%). ICU errors were classified as management errors (82%), diagnostic (9%), technique (5%), and system inadequacies (4%). Davis and colleagues [10] identified critical care errors in 30% of 125 trauma deaths with errors. These errors contributed to 48% of all preventable deaths.The most common critical care errors are related to airway and respiratory management, fluid resuscitation, neurotrauma diagnosis and support, and delayed diagnosis of critical lesions [9,10].It is imperative for the general surgeon who takes care of trauma patients to know how to deal with these critical aspects, to reduce preventable morbidity and mortality. In the next segment, the situations in which the participation of the surgeon is crucial, during the initial phases of reanimation and stabilization of the critically traumatized patient will be discussed. Airway and ventilation managementAirway and respiratory management errors are the most common of those identified by several authors [9][10][11] The cardinal manifestation is a sudden or a rapidly progressing desaturation, frequently accompanied by tachycardia and arrhytmias, and occasionally by agitation. Hypertension announces the cardiovascular collapse, and bradicardia appears immediately after the total collapse [12]. The symptoms should not be attributed to agitation when it is present, and other possible causes must be ruled out before. Diagnosing the complication involves a directed physical examination, the analysis of the airway pressures and ventilator volumes, chest radiographs, and sometimes the measurement of arterial blood gases (ABG), and the urinary bladder pressure ( Table 1).The emergency conditions in which the access to the airways must be gained, the displacement to diagnosis areas or operating room and the agitation, often present, make the critical...

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Monitoring Tissue Oxygenation during Resuscitation of Major Burns

Abstract: Despite adequate global indices of tissue perfusion after 36 hours of resuscitation, tissue monitoring indicated significant deterioration in the splanchnic circulation and in the normal and burnt skin.

Cited by 67 publications

References 54 publications

Photoacoustic ultrasound spectroscopy for assessing red blood cell aggregation and oxygenation

Photoacoustic ultrasound spectroscopy for assessing red blood cell aggregation and oxygenation

Validity of a theoretical model to examine blood oxygenation dependent optoacoustics

Critical Care Issues in the Early Management of Severe Trauma

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