Measurement of Tissue Oximetry in Standing Unsedated and Sedated Horses

Near infrared spectroscopy (NIRS) noninvasively measures peripheral tissue oxygen saturation (StO2) and may be useful to detect early changes in StO2 in anaesthetized and critically ill horses. This study aimed to identify the muscle belly that provided the highest percentage of successful StO2 readings and the highest mean StO2 value. Fifty adult horses were enrolled in a prospective controlled study. StO2 was measured at six different muscles in each horse, for each intervention: hair overlying the muscle was clipped (post clipping: PC), clipped skin was cleaned with chlorhexidine (post-surgical prepping: PP) and medetomidine was administered intravenously (post medetomidine: PM). Mean StO2 values were calculated for each muscle, and a linear effects model was used to assess the effect of muscle group and intervention on StO2. The sartorius muscle gave the highest percentage of successful StO2 values (p < 0.001) and the highest mean (90% CI) StO2 values for the PC, PP and PM interventions. Surgical prepping of the skin increased the success for measurement of StO2 values. For all muscles, administration of medetomidine was associated with lower StO2 values (p < 0.001). In conclusion, of the muscles examined, the sartorius muscle may be the preferred muscle to measure StO2 in horses, and clipping and cleaning of the probe placement site is recommended.

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Cerebral oxygenation for pain monitoring in adults is ineffective: A sequence-randomized, sham controlled study in volunteers

Scandinavian Journal of Pain ◽

10.1016/j.sjpain.2017.05.001 ◽

2017 ◽

Vol 16 (1) ◽

pp. 129-135 ◽

Cited By ~ 1

Author(s):

Christine H. Meyer-Frießem ◽

Gunnar Jess ◽

Esther M. Pogatzki-Zahn ◽

Peter K. Zahn

Keyword(s):

Pain Intensity ◽

Pain Assessment ◽

Near Infrared ◽

Rating Scale ◽

Cerebral Oxygenation ◽

Rank Correlation ◽

Random Order ◽

Controlled Study ◽

Tissue Oxygen Saturation ◽

Experimental Conditions

AbstractBackgroundPain assessment by Numeric Rating Scale (NRS) is considered to be good clinical practice, but objective pain assessment is still a challenge. Near infrared spectroscopy (NIRS) measures cerebral tissue oxygen saturation (SctO2) that increases with cortical-neuronal activity and may provide point-of-care bedside pain monitoring. Analogous to promising studies in newborns, we hypothesize that different levels of SctO2 can probably quantify pain intensity. SctO2 may increase following painful in contrast to non-painful or sham stimuli and may correlate with pain intensity as assessed by NRS in volunteers.MethodsTwenty healthy male students (24.2±1.9 years), recruited via local advertising, were consecutively included in a sequence-randomized, sham-controlled, single-blinded study. SctO2 was recorded continuously with two NIRS sensors on the forehead. After resting, four stimuli were applied in a random order on the right forearm (unexpected and expected electrical pain, expected non-painful and sham stimuli). Blinded subjects were asked to rate each stimulus on NRS. Statistics: RM-ANOVA; Wilcoxon or paired Student t-test; Spearman’s rank correlation; P < .05.ResultsResting volunteers showed SctO2 of 72.65%±3.39. SctO2 significantly increased for about 60 to 70s until a maximum after unexpected painful (74.62%±3.9; P = .022) and sham stimuli (74.07%±3.23; P =.014). Expected painful (P =.139) and non-painful stimuli (P =.455) resulted in no changes in SctO2. NRS scores (median, IQR) were rated significantly higher after expected (5.25, 3.5 to 6.75) than after unexpected (4.5, 3 to 5; P = .008) pain. No strong correlation was found between NRS and SctO2.Conclusions and ImplicationsContrary to our expectations, measuring SctO2 via a two-channel NIRS is not able to remediate the lack of objective bedside pain assessment under standardized experimental conditions in alert adults.

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Detecting Microsurgical Complications with ViOptix Tissue Oximetry in a Pediatric Myocutaneous Free Flap: Case Presentation and Literature Review

Journal of Reconstructive Microsurgery Open ◽

10.1055/s-0038-1626728 ◽

2018 ◽

Vol 03 (01) ◽

pp. e8-e12

Author(s):

Steven Kozusko ◽

Uzoma Gbulie

Keyword(s):

Real Time ◽

Free Flap ◽

Near Infrared ◽

Clinical Symptoms ◽

Tissue Perfusion ◽

Venous Occlusion ◽

Tissue Oxygen Saturation ◽

Real Time Monitoring ◽

Flap Monitoring ◽

Tissue Oximetry

Background Microvascular compromise from arterial or venous occlusion is a common cause of free flap failure. The salvage rate following a microvascular compromise is dependent on detecting the problem early and intervening quickly. Methods The ViOptix tissue oximeter measures tissue oxygen saturation using the near-infrared spectroscopy technology. The ViOptix device has an alarm capability to warn of potential compromise to tissue perfusion. The tissue oximetry readings are visible on the bedside monitor and are relayed to a webpage link, which is accessible on a personal computer or mobile device, allowing real-time monitoring. This article presents a case where real-time monitoring allowed almost immediate detection of inadvertent pedicle compromise allowing flap salvage by repositioning without surgical intervention. Results In the case presented, the patient's nurse inadvertently positioned a pillow under the location of the vascular pedicle likely causing microvascular compression. The ViOptix reading dropped and for this reason the nurse contacted the Plastic Surgery team. The drop was confirmed remotely and the flap was urgently evaluated in person. Once the pillow was removed, the ViOptix readings normalized and Doppler signals strengthened in the flap. Discussion While tissue oximetry monitoring does not by itself ensure flap survival, it provides critical information than conventional flap monitoring would allow giving the microsurgeon the opportunity to make a quicker decision. ViOptix tissue oximeters are able to detect vascular compromise even before conventional clinical symptoms are present. Alas in several cases by the time clinical symptoms develop the flap may be beyond salvage.

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