Near-infrared spectroscopy identifies compartment syndrome in an infant

Comparison and convergence of compartment syndrome techniques: a narrative review

INTRODUCTION

Compartment syndrome (CS) continues to be a legitimate orthopedic emergency as it leads to thousands of amputations and permanent nerve and tissue damage to undiagnosed patients for more than eight hours. In CS, intracompartmental pressure is elevated, causing reduced blood flow inside the limb compartments. An erroneous diagnosis may result in unnecessary fasciotomies, the only treatment for this condition.

AREAS COVERED

This review examines the previous and current diagnostic and therapeutic practices for compartment syndrome. It also performs a comparative analysis of each diagnostic technique and its foresights.

EXPERT OPINION

Currently, most clinicians rely on a physical examination of the patient to diagnose CS. The primary reason for the physical examination is the lack of a gold-standard device. The invasive intracompartmental pressure (ICP) measurement technique is still the most commonly used. On the other hand, many non-invasive approaches have the potential to be used as diagnostic tools; however, more research is needed before they can be accepted as standard clinical approaches.

Do Cerebral Cortex Perfusion, Oxygen Delivery, and Oxygen Saturation Responses Measured by Near-Infrared Spectroscopy Differ Between Patients Who Fail or Succeed in a Spontaneous Breathing Trial? A Prospective Observational Study

BACKGROUND

Alterations in perfusion to the brain during the transition from mechanical ventilation (MV) to a spontaneous breathing trial (SBT) remain poorly understood. The aim of the study was to determine whether changes in cerebral cortex perfusion, oxygen delivery (DO₂), and oxygen saturation (%StiO₂) during the transition from MV to an SBT differ between patients who succeed or fail an SBT.

METHODS

This was a single-center prospective observational study conducted in a 16-bed medical intensive care unit of the University Hospital Leuven, Belgium. Measurements were performed in 24 patients receiving MV immediately before and at the end of a 30-min SBT. Blood flow index (BFI), DO₂, and %StiO₂ in the prefrontal cortex, scalene, rectus abdominis, and thenar muscle were simultaneously assessed by near-infrared spectroscopy using the tracer indocyanine green dye. Cardiac output, arterial blood gases, and systemic oxygenation were also recorded.

RESULTS

During the SBT, prefrontal cortex BFI and DO₂ responses did not differ between SBT-failure and SBT-success groups (p > 0.05). However, prefrontal cortex %StiO₂ decreased in six of eight patients (75%) in the SBT-failure group (median [interquartile range 25-75%]: MV = 57.2% [49.1-61.7] vs. SBT = 51.0% [41.5-62.5]) compared to 3 of 16 patients (19%) in the SBT-success group (median [interquartile range 25-75%]: MV = 65.0% [58.6-68.5] vs. SBT = 65.1% [59.5-71.1]), resulting in a significant differential %StiO₂ response between groups (p = 0.031). Similarly, a significant differential response in thenar muscle %StiO₂ (p = 0.018) was observed between groups. A receiver operating characteristic analysis identified a decrease in prefrontal cortex %StiO₂ > 1.6% during the SBT as an optimal cutoff, with a sensitivity of 94% and a specificity of 75% to predict SBT failure and an area under the curve of 0.79 (95% CI: 0.55-1.00). Cardiac output, systemic oxygenation, scalene, and rectus abdominis BFI, DO₂, and %StiO₂ responses did not differ between groups (p > 0.05); however, during the SBT, a significant positive association in prefrontal cortex BFI and partial pressure of arterial carbon dioxide was observed only in the SBT-success group (SBT success: Spearman's ρ = 0.728, p = 0.002 vs. SBT failure: ρ = 0.048, p = 0.934).

CONCLUSIONS

This study demonstrated a reduced differential response in prefrontal cortex %StiO₂ in the SBT-failure group compared with the SBT-success group possibly due to the insufficient increase in prefrontal cortex perfusion in SBT-failure patients. A > 1.6% drop in prefrontal cortex %StiO₂ during SBT was sensitive in predicting SBT failure. Further research is needed to validate these findings in a larger population and to evaluate whether cerebral cortex %StiO₂ measurements by near-infrared spectroscopy can assist in the decision-making process on liberation from MV.

Clinical and Technical Limitations of Cerebral and Somatic Near-Infrared Spectroscopy as an Oxygenation Monitor

Cerebral and somatic near-infrared spectroscopy monitors are commonly used to detect tissue oxygenation in various circumstances. This form of monitoring is based on tissue infrared absorption and can be influenced by several physiological and non-physiological factors that can induce error in the interpretation. This narrative review explores those clinical and technical limitations and proposes solutions and alternatives in order to avoid some of those pitfalls.

Diagnostic Modalities for Acute Compartment Syndrome of the Extremities: A Systematic Review

Importance

Acute compartment syndrome (ACS) can cause catastrophic tissue damage leading to permanent muscle and nerve loss. Acute compartment syndrome is a clinical diagnosis, with intracompartmental pressure (ICP) used in equivocal cases. There are no reliable diagnostic methods. The clinical evaluation is impossible to standardize, and the threshold for ICP has been known to be unreliable; thus, guidelines for diagnosis can result in overtreatment or delayed diagnosis.

Objective

To present and review the advantages and disadvantages of each diagnostic modality and identify gaps that need to be addressed in the future and to review the most used and appropriate animal and human ACS models.

Evidence Review

We included clinical studies and animal models investigating diagnostic modalities for ACS of the extremities. A MEDLINE and Web of Science search was performed. The protocol for the study was registered on PROSPERO (CRD42017079266). We assessed the quality of the clinical studies with Newcastle-Ottawa scale and reported level of evidence for each article.

Findings

Fifty-one articles were included in this study, reporting on 38 noninvasive and 35 invasive modalities. Near-infrared spectroscopy and direct ICP measurement using a Stryker device were the most common, respectively. Cadaveric studies used saline infusions to create an ACS model. Most studies with human participants included injured patients with acquired ACS or at risk of developing ACS. In healthy human participants, tourniquets formed the most commonly used ACS model. Application of tourniquets and infusion of saline or albumin were the most used ACS models among animal studies.

Conclusions and Relevance

This article reports on the most common as well as many new and modified diagnostic modalities, which can serve as inspiration for future investigations to develop more effective and efficient diagnostic techniques for ACS. Future studies on diagnostic modalities should include the development of tools for continuous assessment of ICP to better identify the earliest alterations suggestive of impending ACS. With the advent of such technologies, it may be possible to develop far less aggressive and more effective approaches for early detection of ACS.

Use of Near-Infrared Spectroscopy to Monitor Lower Extremity Perfusion in Pediatric Patients Undergoing Cardiac Catheterization

Acute femoral artery occlusion is common in pediatric patients following cardiac catheterization. A variety of means are utilized to assess lower extremity (LE) perfusion and arterial patency following cardiac catheterization including palpation of pulses, pulse oximetry, subjective assessment of lower extremity color and temperature, and ultrasound. We sought to evaluate the utility of Near-Infrared Spectroscopy (NIRS) to monitor LE perfusion in pediatric patients undergoing cardiac catheterization. INVOS pediatric sensors were placed on bilateral LE in all pediatric patients ≤ 40 kg undergoing cardiac catheterization. Data were recorded continuously from the start of the procedure until 4-6 h after completion of the procedure. NIRS readings were compared between the accessed versus non-accessed LE at baseline before start of case, time of vascular access, arterial sheath exchange when applicable, sheath withdrawal, and Safeguard application, deflation, and removal. 133 patients underwent 152 catheterizations with mean age 2.4 ± 2.3 years and mean weight 12.4 ± 13.2 kg. NIRS oximetry readings were significantly decreased in the LE with arterial access compared to non-accessed LE from time of sheath insertion until removal of the pressure assist device post procedure. A greater difference was noted in smaller patients. NIRS oximetry readings did not correlate with subjective assessment of lower extremity perfusion after arterial sheaths were removed. One patient had pulse loss 4 h post procedure with a decrease in oximetry readings noted at this point on review. Weight-based heparin protocol was initiated, and a gradual improvement in oximetry readings was noted over the next 5 h. Vascular ultrasound 12 h later showed no evidence of arterial thrombus. NIRS may be helpful in identifying patients who are risk for developing arterial thrombus post cardiac catheterization and for monitoring response to therapy; however, further study in these patients is warranted.

Diagnosing acute compartment syndrome-where have we got to?

Purpose

Acute compartment syndrome is a condition whereby tissue ischaemia occurs due to increased pressure in a closed myofascial compartment. It is a surgical emergency, with rapid recognition and treatment—the keys to good outcomes.

Methods

The available literature on diagnostic aids was reviewed by one of the senior authors 15 years ago. Now, we have further reviewed the literature, to aim to ascertain what progress has been made.

Results

In this review, we present the evidence around a variety of available diagnostic options when investigating a potential case of acute compartment syndrome, including those looking at pressure changes, localised oxygenation, perfusion, metabolic changes and available blood serum biomarkers.

Conclusions

A significant amount of work has been put into developing modalities of diagnosis for acute compartment syndrome in the last 15 years. There is a lot of promising outcomes being reported; however, there is yet to be any conclusive evidence to suggest that they should be used over intracompartmental pressure measurement, which remains the gold standard. However, clinicians should be cognizant that compartment pressure monitoring lacks diagnostic specificity, and could lead to unnecessary fasciotomy when used as the sole criterion for diagnosis. Therefore, pressure monitoring is ideally used in situations where clinical suspicion is raised.

Lower limb perfusion during robotic-assisted laparoscopic radical prostatectomy evaluated by near-infrared spectroscopy: an observational prospective study

Background

Decreased perfusion in the lower extremities is one of the several adverse effects of placing patients in a lithotomy or Trendelenburg position during surgery. This study aimed to evaluate the effects of patient positioning in lower limb perfusion patients undergoing robotic-assisted laparoscopic radical prostatectomy (RARP) using near-infrared spectroscopy (NIRS).

Methods

This observation study comprised 30 consenting males with American Society of Anaesthesiologists physical status classes I and II (age range, ≥20 to < 80 years). Regional saturation of oxygen measurements was obtained using an INVOS™ oximeter (Somanetics, Troy, MI, USA). A NIRS sensor was positioned on the surface of the skin at the mid-diaphyseal region of the calf muscles (the gastrocnemius and soleus), over the posterior compartment, in the right lower leg. Regional saturation of oxygen (rSO₂) was sampled during the following time points: before and 5 min after induction of anaesthesia (T0,T1); 5 min after establishment of pneumoperitoneum in a 0° lithotomy position (T2); 5 min after a 25° Trendelenburg position (T3); 30, 60, 90 and 120 min after pneumoperitoneum in a Trendelenburg position (T4, T5, T6 and T7, respectively); after desufflation in a supine position (T8); and after tracheal extubation (T9).

Results

Lower limb perfusion evaluated by NIRS was increased after induction of anaesthesia and maintained during steep Trendelenburg positions in RARP patients with no risk for lower limb compartment syndrome (LLCS) (T0:65 ± 7.2%, T1:69 ± 6.1%, T2:70±:6.1%, T3:68 ± 6.7%, T4:66 ± 7.5%, T5:67 ± 6.9%, T6:68 ± 7.2%, T8:73 ± 7.2%, T9:71 ± 7.9%, respectively).

Conclusions

Lower limb perfusion evaluated by NIRS was maintained during the RARP procedure. Correct patient positioning and careful assessment of risk factors such as vascular morbidity could be important for the prevention of LLCS during RARP.

Compartment syndrome in infants and toddlers

PURPOSE

To study the cause, diagnosis, treatment and outcome of acute compartment syndrome in infants and toddlers aged <3 years.

METHODS

Fifteen patients aged <3 years with acute compartment syndrome were identified from two large pediatric trauma centers over a fifteen-year period. All children underwent fasciotomy. The mechanism of injury, time of injury, time to diagnosis, compartment pressures, time to fasciotomy, and outcome at the time of the latest follow-up were recorded.

RESULTS

Nine (60 %) of fifteen patients developed compartment syndrome secondary to trauma, four (4/15, 27 %) due to infection, and two (2/15, 13 %) due to intravenous infiltration. The average time from injury or hospital admission to fasciotomy was 31.8 h (range 2.9-136.3 h). In general, the functional outcome was excellent at the latest follow-up with thirteen (13/15, 87 %) patients having an excellent outcome. No cases of Volkmann's ischemia were noted at the time of fasciotomy, even when performed as late as 5 days after injury.

CONCLUSIONS

Compared to the general pediatric population, the diagnosis of compartment syndrome in infants and toddlers may be further delayed, i.e., >24 h after injury. Despite delays in diagnosis and time to treatment, the present study shows that outcomes in infants and toddlers remain favorable even when fasciotomy is performed 48-72 h after injury.

LEVEL OF EVIDENCE

Case series, level IV.

Compartment Syndrome in Children

Compartment syndrome in children can present differently than adults. Increased analgesic need should be considered the first sign of evolving compartment syndrome in children. Children with supracondylar humerus fractures, floating elbow injuries, operatively treated forearm fractures, and tibia fractures are at high risk for developing compartment syndrome. Elbow flexion beyond 90° in supracondylar humerus fractures and closed treatment of forearm fractures in floating elbow injuries are associated with increased risk of compartment syndrome. Prompt diagnosis and treatment with fasciotomy in children result in excellent long-term outcomes.

Acute compartment syndrome of the limbs: current concepts and management

Acute compartment syndrome (ACS) of the limb refers to a constellation of symptoms, which occur following a rise in the pressure inside a limb muscle compartment. A failure or delay in recognising ACS almost invariably results in adverse outcomes for patients. Unrecognised ACS can leave patients with nonviable limbs requiring amputation and can also be life–threatening. Several clinical features indicate ACS. Where diagnosis is unclear there are several techniques for measuring intracompartmental pressure described in this review. As early diagnosis and fasciotomy are known to be the best determinants of good outcomes, it is important that surgeons are aware of the features that make this diagnosis likely. This clinical review discusses current knowledge on the relevant clinical anatomy, aetiology, pathophysiology, risk factors, clinical features, diagnostic procedures and management of an acute presentation of compartment syndrome.

Ultrasound-guided upper extremity blocks - tips and tricks to improve the clinical practice

Brachial plexus blockade in children can be used for a broad spectrum of clinical indications. Nevertheless, these regional anesthetic techniques are still underused in pediatric anesthesia that is mainly because of insufficient descriptions of the particular techniques. Ultrasound guidance enables direct visualization of neuronal and adjacent anatomical structures, the cannula, and the spread of local anesthetic. The most important issue in this context is theoretical background knowledge and intensive training of hand skills. The following review article discusses all relevant aspects of ultrasound-guided brachial plexus blockade.

Noninvasive tissue oxygen saturation determined by near-infrared spectroscopy following peripheral nerve block

BACKGROUND

Noninvasive physiologic measurement of cutaneous tissue oxygenation using near-infrared spectroscopy (NIRS) has become increasingly common in cardiovascular and plastic surgery. The aim of this study was to determine whether clinically available NIRS-based monitors could detect changes in tissue oxygen saturation (rSO(2)) following a variety of peripheral nerve blocks. We hypothesize that peripheral nerve blocks will produce detectable changes in cutaneous tissue oxygenation levels that can be measured by noninvasive NIRS-based oximetry.

METHODS

Forty adult patients scheduled for pre-operative peripheral nerve block placement were enrolled. Prior to block placement, NIRS sensors were placed on the operative and nonoperative (control) limb. Baseline tissue oxygen saturation values were obtained prior to dosing of the nerve block, and measurements were recorded every 5 min thereafter.

RESULTS

Initial rSO(2) values were higher in the operative vs. control limbs prior to nerve block placement. Tissue oxygen saturation increased in the blocked, but not control, limbs with time. Subgroup analysis suggested statistically significant differences in rSO(2) values in blocked vs. control limbs for cervical paravertebral, infraclavicular, and femoral nerve blocks.

CONCLUSIONS

Our results demonstrated sustained increases in tissue rSO(2) values following peripheral nerve block placement, in addition to higher initial rSO(2) values in operative limbs prior to block placement. Further investigations are necessary to define the expected baseline rSO(2) values in operative and control limbs. Future efforts utilizing NIRS-based detection of tissue ischemia should consider the small but significant changes in rSO(2) resulting from a successful nerve block.

Near-infrared spectroscopy in the critical setting

Near-infrared spectroscopy is a noninvasive means of determining real-time changes in regional oxygen saturation of cerebral and somatic tissues. Hypoxic neurologic injuries not only involve devastating effects on patients and their families but also increase health care costs to the society. At present, monitors of cerebral function such as electroencephalograms, transcranial Doppler, jugular bulb mixed venous oximetry, and brain tissue oxygenation monitoring involve an invasive procedure, are operator-dependent, and/or lack the sensitivity required to identify patients at risk for cerebral hypoxia. Although 20th century advances in the understanding and management of resuscitation of critically ill and injured children have focused on global parameters (ie, pulse oximetry, capnography, base deficit, lactate, etc), a growing body of evidence now points to regional disturbances in microcirculation that will lead us in a new direction of adjunctive tissue monitoring and response to resuscitation. In the coming years, near-infrared spectroscopy will be accepted as a way for clinicians to more quickly and noninvasively identify patients with altered levels of cerebral and/or somatic tissue oxygenation and, in conjunction with global physiologic parameters, guide efficient and effective resuscitation to improve outcomes for critically ill and injured pediatric patients.

Correlation between muscle oxygenation and compartment pressures in acute compartment syndrome of the leg

BACKGROUND

Near-infrared spectroscopy estimates soft-tissue oxygenation approximately 2 to 3 cm below the skin. The purpose of the present study was to evaluate muscle oxygenation in the setting of an acute compartment syndrome of the leg and to determine if near-infrared spectroscopy is capable of detecting perfusion deficits.

METHODS

Fourteen patients with unilateral lower extremity trauma were enrolled after the diagnosis of an acute compartment syndrome was made clinically and confirmed with intracompartmental pressure measurements. Lower extremity muscle compartments were evaluated with near-infrared spectroscopy, and near-infrared spectroscopy values of the uninjured, contralateral leg of each patient were used as internal reference values. The compartment perfusion gradient was calculated as the diastolic blood pressure minus the intracompartmental pressure.

RESULTS

Intracompartmental pressures ranged from 21 to 176 mm Hg (mean, 79 mm Hg) and exceeded 30 mm Hg in all compartments but two (both in the same patient). Thirty-eight compartments had a perfusion gradient of < or = 10 mm Hg (indicating ischemia). Among ischemic compartments, near-infrared spectroscopy values in the anterior, lateral, deep posterior, and superficial posterior compartments of the injured limbs were decreased by an average 10.1%, 10.1%, 9.4%, and 16.3% in comparison with the corresponding compartments of the uninjured leg. Differences in near-infrared spectroscopy values (the near-infrared spectroscopy value for the injured leg minus the near-infrared spectroscopy value for the uninjured leg) were positively correlated with compartment perfusion gradient within each compartment (r = 0.82, 0.65, 0.67, and 0.62, for the anterior, lateral, deep posterior, and superficial posterior compartments, respectively; p < 0.05 for all).

CONCLUSIONS

Normalized near-infrared spectroscopy values decrease significantly with decreasing lower limb perfusion pressures. Near-infrared spectroscopy may be capable of differentiating between injured patients with and without an acute compartment syndrome.

Near-infrared spectroscopy as an index of brain and tissue oxygenation

Continuous real-time monitoring of the adequacy of cerebral perfusion can provide important therapeutic information in a variety of clinical settings. The current clinical availability of several non-invasive near-infrared spectroscopy (NIRS)-based cerebral oximetry devices represents a potentially important development for the detection of cerebral ischaemia. In addition, a number of preliminary studies have reported on the application of cerebral oximetry sensors to other tissue beds including splanchnic, renal, and spinal cord. This review provides a synopsis of the mode of operation, current limitations and confounders, clinical applications, and potential future uses of such NIRS devices.

Hemodynamic changes in rat leg muscles during tourniquet-induced ischemia-reperfusion injury observed by near-infrared spectroscopy

In this study, we hypothesized that non-invasive continuous wave near-infrared spectroscopy (CWNIRS) can determine the severity or reversibility of muscle damage due to ischemia/reperfusion (I/R), and the results will be highly correlated with those from physical examination and histological analysis. To test this hypothesis, we performed CWNIRS measurements on two groups of male Sprague-Dawley rats ( approximately 400 g) that underwent 2 h (n = 6) or 3 h (n = 7) of pneumatic tourniquet application (TKA). Tissue oxyhemoglobin [HbO(2)] and deoxyhemoglobin [Hb] concentration changes were monitored during the 2 h or 3 h of 250 mmHg TKA and for an additional 2 h post-TKA. Rats were euthanized 24 h post-TKA and examined for injury, edema and viability of muscles. Contralateral muscles served as controls for each animal. In both groups, [HbO(2)] dropped immediately, then gradually decreased further after TKA and then recovered once the tourniquet was released. However, releasing after 2 h of TKA caused [HbO(2)] to overshoot above the baseline during reperfusion while the 3 h group continued to have lower [HbO(2)] than baseline. We found a significant correlation between the elapsed time from tourniquet release to the first recovery peak of [HbO(2)] and the muscle weight ratio between tourniquet and contralateral limb muscles (R = 0.86). Hemodynamic patterns from non-invasive CWNIRS demonstrated significant differences between 2 h and 3 h I/R. The results demonstrate that CWNIRS may be useful as a non-invasive prognostic tool for conditions involving vascular compromise such as extremity compartment syndrome.

Does epidural analgesia delay the diagnosis of lower limb compartment syndrome in children?

One of the cardinal symptoms of compartment syndrome is pain. A literature review was undertaken in order to assess the association of epidural analgesia and compartment syndrome in children, whether epidural analgesia delays the diagnosis, and to identify patients who might be at risk. Evidence was sought to offer recommendations in the use of epidural analgesia in patients at risk of developing compartment syndrome of the lower limb. Increasing analgesic use, increasing/breakthrough pain and pain remote to the surgical site were identified as important early warning signs of impending compartment syndrome in the lower limb of a child with a working epidural. The presence of any should trigger immediate examination of the painful site, and active management of the situation (we have proposed one clinical pathway). Avoidance of dense sensory or motor block and unnecessary sensory blockade of areas remote to the surgical site allows full assessment of the child and may prevent any delay in diagnosis of compartment syndrome. Focusing on excluding the diagnosis of compartment syndrome rather than failure of analgesic modality is vital. In the pediatric cases reviewed there was no clear evidence that the presence of an epidural had delayed the diagnosis.

Diagnostic techniques in acute compartment syndrome of the leg

OBJECTIVES

To review the efficacy of the current diagnostic methods of acute compartment syndrome (ACS) after leg fractures.

DATA SOURCES

A Medline (PubMed) search of the English literature extending from 1950 to May 2007 was performed using "compartment syndromes" as the main key word. Also a manual search of orthopaedic texts was performed.

STUDY SELECTION AND EXTRACTION

The results were limited to articles involving human subjects. Of 2605 primary titles, 489 abstracts limited to compartment syndromes in the leg and 577 articles related to the diagnosis of compartment syndromes were identified and their abstracts reviewed. Further articles were identified by reviewing the references. Sixty-six articles were found to be relevant to diagnostic techniques for compartment syndrome in the leg and formed the basis of this review.

CONCLUSIONS

Early diagnosis of an ACS is important. Despite its drawbacks, clinical assessment is still the diagnostic cornerstone of ACS. Intracompartmental pressure measurement can confirm the diagnosis in suspected patients and may have a role in the diagnosis of this condition in unconscious patients or those unable to cooperate. Whitesides suggests that the perfusion of the compartment depends on the difference between the diastolic blood pressure and the intracompartmental pressure. They recommend fasciotomy when this pressure difference, known as the Delta p, is less than 30 mm Hg. Access to a precise, reliable, and noninvasive method for early diagnosis of ACS would be a landmark achievement in orthopaedic and emergency medicine.

Lack of irrefutable validation does not negate clinical utility of near-infrared spectroscopy monitoring: learning to trust new technology

Reliance on new monitoring device technology is based upon an understanding of how the device operates and its reliability in a specific clinical setting. The introduction of new monitoring devices will therefore elicit either distrust of the new technology and the data presented or adoption of new devices. The use of near-infrared spectroscopy (NIRS) technology to monitor vital organs in postoperative pediatric cardiac surgery patients has been extensively described yet controversy remains as to the use of this monitoring device. The following retrospective case series demonstrates how learning from trends in data elicited from 2-site NIRS monitoring provided important bedside insights. These insights led to changes in clinician behavior and reliance on NIRS monitoring for early recognition of clinically silent deteriorations. Disregard for the NIRS data may have led to a fatal outcome in an unstable patient who might have received more timely intervention if the NIRS data had been acknowledged earlier. This case series demonstrates that 2-site NIRS monitoring accurately reflects situations in which poor clinical outcomes may occur when declining trends in somatic tissue oxygen saturations are not corrected. Physician management of the postoperative pediatric cardiac surgery patient can change based upon the insights gained through the application of NIRS monitoring.

Near Infrared Spectroscopy (NIRS) in Children

Near infrared spectroscopy (NIRS) is a noninvasive method for the in vivo monitoring of tissue oxygenation. Originally used predominantly to assess cerebral oxygenation, NIRS has gained widespread popularity in many clinical settings in all age groups. Changes in regional tissue oxygenation as detected by NIRS may reflect the delicate balance between oxygen delivery and consumption in more than one organ system. However, more studies are required to establish the ability of NIRS monitoring to improve patient outcome. This review provides a comprehensive description of NIRS in children.

Compartment syndrome of the thigh in an infant: a case report

Compartment syndrome of the thigh in children is rare. We report a case of compartment syndrome of the thigh in an infant with a femur fracture resulting from suspected nonaccidental trauma. The delayed presentation of this injury may have been contributory to the development of compartment syndrome. The subtle physical findings in this case underscore the need for a high index of suspicion in making the diagnosis of compartment syndrome. The complete recovery of muscle function, even in the presence of significant tissue damage, is noteworthy and suggests that infants have a greater physiologic ability to recover in comparison with adults.

Acute Complications of Extremity Trauma

In addition to the large number of patients with isolated limb injuries, many patients with major blunt or penetrating trauma harbor extremity injuries as a component of their overall clinical picture. Extremity injuries range from gross deformities and amputations to more subtle injuries, potentially difficult to diagnose, or may escape detection in unconscious or intoxicated patients. However, many soft tissue and vascular injuries require time sensitive interventions to ensure salvage of the limb and the best outcome for the patient. This article reviews the acute management of vascular and soft tissue injuries in the emergency department.