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

Pain Control for Sickle Cell Crisis, a Novel Approach? A Retrospective Study

Background and Objectives: Pain management poses a significant challenge for patients experiencing vaso-occlusive crisis (VOC) in sickle cell disease (SCD). While opioid therapy is highly effective, its efficacy can be impeded by undesirable side effects. Local regional anesthesia (LRA), involving the deposition of a perineural anesthetic, provides a nociceptive blockade, local vasodilation and reduces the inflammatory response. However, the effectiveness of this therapeutic approach for VOC in SCD patients has been rarely reported up to now. The objective of this study was to assess the effectiveness of a single-shot local regional anesthesia (LRA) in reducing pain and consequently enhancing the management of severe vaso-occlusive crisis (VOC) in adults with sickle cell disease (SCD) unresponsive to conventional analgesic therapy. Materials and Methods: We first collected consecutive episodes of VOC in critical care (ICU and emergency room) for six months in 2022 in a French University hospital with a large population of sickle cell patients in the West Indies population. We also performed a systematic review of the use of LRA in SCD. The primary outcome was defined using a numeric pain score (NPS) and/or percentage of change in opioid use. Results: We enrolled nine SCD adults (28 years old, 4 females) for ten episodes of VOC in whom LRA was used for pain management. Opioid reduction within the first 24 h post block was -75% (50 to 96%). Similarly, the NPS decreased from 9/10 pre-block to 0-1/10 post-block. Five studies, including one case series with three patients and four case reports, employed peripheral nerve blocks for regional anesthesia. In general, local regional anesthesia (LRA) exhibited a reduction in pain and symptoms, along with a decrease in opioid consumption post-procedure. Conclusions: LRA improves pain scores, reduces opioid consumption in SCD patients with refractory pain, and may mitigate opioid-related side effects while facilitating the transition to oral analgesics. Furthermore, LRA is a safe and effective procedure.

Evaluation of distal skin temperature and tissue oxygen saturation determined by near-infrared spectroscopy for predicting ultrasound-guided lateral infraclavicular block success

BACKGROUND

Changes in tissue oxygen saturation determined by near-infrared spectroscopy (NIRS) may help predict and determine the success of a lateral infraclavicular (LIC) block.We investigated whether evaluation of tissue oxygen saturation determined by NIRS couldbe an indicator of LIC block success.

METHODS

Forty patients scheduled for hand or forearm surgery under LIC block were studied. NIRS sensors were placed on the ventral aspect of both mid-forearms, and the contralateral hand was used as the control group. NIRS values were recorded before the block andat regular intervals during the following 30 min.

RESULTS

NIRS values were significantly higher in the successfully blocked patients whencompared to the complete failure, partial failure, and contralateral hand groups at the 10thmin. In the successfully blocked patients, NIRS values (mean ± SD [change in %]) increasedby 11.09 ± 4.86 (16.03%), 15.00 ± 4.53 (21.76%), 16.35 ± 5.14 (23.77%), 16.38 ± 4.88(23.85%), 16.67 ± 5.04 (24.29%), and 16.96 ± 5.71 (24.78%), respectively, from baselineto 5, 10, 15, 20, 25, and 30 min. ΔTs values were significantly higher in the successfullyblocked patients than in the complete failure patients and contralateral hand at the 30thmin. However, there was no statistically significant difference when comparing ΔTs values ofsuccessful block and partial failure block patients at the 30th min.

CONCLUSIONS

We conclude that measurement of tissue oxygen saturation by NIRS withinthe scope of evaluation of the lateral infraclavicular block is a rapid, effective, and applicabletechnique.

İnfraklaviküler ve interskalen bloğun önkol oksijenasyonuna etkisi: randomize kontrollü bir çalışma

Amaç: Ultrasonografi görüntüleme (USG) eşliğinde yapılan infraklaviküler blok (İKB) ve interskalen blok (İSB), üst ekstremite ameliyatlarında en sık kullanılan brakiyal pleksus blok teknikleridir. Bu blokların uygulanmasından sonra sempatik blokaj oluştuğu ve blokajın neden olduğu vazodilatasyon ile kan akımının arttığı bilinmektedir. Bu çalışmada USG ile birlikte uygulanan İKB ve İSB'nin önkol doku oksijenasyonuna etkisinin karşılaştırılması amaçlandı. Gereç ve Yöntem: Bu çalışmaya elektif veya acil kol, dirsek veya önkol cerrahisi planlanan 18-65 yaş arası ASA I-III risk gruplarına ait yüz dört hasta dahil edildi. Hastalar iki gruba ayrıldı: Grup İKB ve Grup İSB. Bazal hemodinamik ölçümlere ek olarak, blok öncesi ve blok tamamlandıktan sonra 10., 20. ve 30. dakikalarda Perfüzyon indeksi(PI), ortalama akım hızı(TAV), brakiyal arter çapı(BAÇ), brakiyal arter alanı(BAA), brakiyal arter atım akımı (BF) ve doku oksijen satürasyonu(rSO2) verileri önceden kaydedildi. Bulgular: Grup İSB ve Grup İKB'deki hastaların demografik verileri karşılaştırıldı, gruplar arasında anlamlı fark saptanmadı. PI ve rSO2 değerlerindeki artış yüzdelerinin zamana göre dağılımı incelendiğinde, gruplar arasında anlamlı farklılıklar bulundu. 0. dakika ile 10., 20. ve 30. dakikalar arasında BF, TAV, BAA ve BAÇ değerlerindeki yüzde artışlarında anlamlı fark yoktu. Grup İSB'de 8 hastada (%15) Horner sendromu, 3 hastada (%5) ani ses kısıklığı gözlendi. Grup İKB'de komplikasyon gelişmedi. Sonuç: Bu çalışmada İKB ve İSB'nin önkol doku oksijenasyonu üzerindeki etkilerinin karşılaştırıldığı ve İKB'nin rSO2 ve PI değerlerini arttırdığı tespit edilmiştir.

Regional anesthesia for sickle cell disease vaso-occlusive crisis: A single-center case series

Pain management is challenging for patients with sickle cell disease (SCD) who present in vaso-occlusive crisis (VOC). Opioid therapy is highly effective, nevertheless undesirable side effects can hinder their effectiveness. Regional anesthesia with deposition of perineural anesthetic offers nociceptive blockade, local vasodilatation, and reduces the inflammatory response. Among pediatric patients, continuous peripheral nerve block (CPNB) for perioperative adjunctive analgesia is safe. Herein, we describe the trajectory of a cohort of pediatric SCD patients with opioid-refractory upper-extremity VOC following placement of CPNBs for analgesia; highlighting reduced opioid consumption, improved pain scores, and decreased length of hospitalization.

Effects of adding a combined femoral and sciatic nerve block with levobupivacaine and clonidine to general anaesthesia in femoropopliteal bypass surgery: A randomised, double-blind, controlled trial

BACKGROUND

Adding a regional block to general anaesthesia can prevent postoperative pain and improve peripheral circulation.

OBJECTIVE

To seek improved postoperative analgesia and care due to a long-acting combined femoral and sciatic nerve block in patients undergoing femoropopliteal bypass surgery.

DESIGN

A randomised, double-blind, controlled trial.

SETTING

Vascular surgery unit of a French university hospital.

PATIENTS

Forty-four adults scheduled for bypass surgery under general anaesthesia.

INTERVENTION

Patients were allocated to receive either an active nerve block with 20 ml of 0.375% levobupivacaine and clonidine 0.5 μg kg, or a simulated (sham) block only, but with local anaesthesia of the skin, before general anaesthesia. General anaesthesia was standardised with propofol, then sevoflurane and sufentanil adjusted according to clinical need. Postoperative analgesia was standardised with paracetamol 1 g every 6 h, and intravenous morphine, initially titrated in the postanaesthesia care unit and then patient-controlled. Oral analgesics were repeated up to day 3.

MAIN OUTCOME MEASURES

The primary outcome was morphine consumption during the first 24 postoperative hours. In a subgroup of postoperative patients distal tissue oxygen saturation was recorded at the lateral side of the blocked calf.

RESULTS

Patients in the active group received less intra-operative sufentanil (median dose 25 vs. 41 μg), needed less morphine during the first 24 h (15 vs. 27 mg) and 72 (20 vs. 35 mg) postoperative hours, than in the control group. They also had less pain on movement, but pain at rest, the tissue oxygen saturation and other rehabilitation outcomes were unaffected by the treatment. Tolerance outcomes were also similar between groups.

CONCLUSION

Combining the two regional blocks improves the quality of postoperative care in this frail population, probably by reducing the amount of peri-operative opioid.

TRIAL REGISTRATION

ClinicalTrials.gov (ref. NCT01785693).

Tissue Oxygen Saturation Change on Upper Extremities After Ultrasound-Guided Infraclavicular Brachial Plexus Blockade; Prospective Observational Study

Background and Objective: The aim of this study was to investigate whether tissue oxygen saturation (StO2) is a reliable and objective method for assessing the adequacy of infraclavicular block and to describe the time course of StO2 changes. Materials and Methods: In this prospective observational study, StO2 was measured in 40 patients planned for elective hand surgery under infraclavicular block. Noninvasive StO2 monitoring was used prior to ultrasound-guided infraclavicular brachial plexus block and during the first 30 min of the blockade. Sensory and motor blocks were evaluated every 5 min followed by pinprick testing and Bromage scale. Results: Preanesthetic median StO2 values of the blocked side and nonblocked side were similar (p = 0.532), whereas the postanesthetic values of the blocked side were higher. At the fifth minute and the following minute, measurements compared to the nonblocked side (p < 0.001). The median StO2 values increased significantly, which increased by 4.5% at 5 min, by another 5.5% at 30 min, and by an average of 1% from 5 to 30 min compared to the baseline values in the blocked side. The responses of the patients to the questions probed in the pinprick test and Bromage scale were fully compatible with the data obtained by the near-infrared spectroscopy (NIRS) method. Conclusions: StO2 monitoring may provide a useful instrument for rapid evaluation of the success of regional anesthesia in the upper extremity.

Effect of bupivacaine and adjuvant drugs for regional anesthesia on nerve tissue oximetry and nerve blood flow

Background

Nerve blood flow has a critical role in acute and chronic pathologies in peripheral nerves. Influences of local anesthetics and adjuvants on tissue perfusion and oxygenation are deemed as relevant factors for nerve damage after peripheral regional anesthesia. The link between low tissue perfusion due to local anesthetics and resulting tissue oxygenation is unclear.

Methods

Combined tissue spectrophotometry and laser-Doppler flowmetry were used to assess nerve blood flow in 40 surgically exposed median nerves in pigs, as well as nerve tissue oximetry for 60 min. After baseline measurements, test solutions saline (S), bupivacaine (Bupi), bupivacaine with epinephrine (BupiEpi), and bupivacaine with clonidine (BupiCloni) were applied topically.

Results

Bupivacaine resulted in significant decrease in nerve blood flow, as well as tissue oximetry values, compared with saline control. Addition of epinephrine resulted in a rapid, but nonsignificant, reduction of nerve blood flow and extensive lowering of tissue oximetry levels. The use of clonidine resulted in a reduction of nerve blood flow, comparable to bupivacaine alone (relative blood flow at T60 min compared with baseline, S: 0.86 (0.67-1.18), median (25th-75th percentile); Bupi: 0.33 (0.25-0.60); BupiCloni: 0.43 (0.38-0.63); and BupiEpi: 0.41(0.30-0.54). The use of adjuvants did not result in any relevant impairment of tissue oximetry values (saturation values in percent at T60, S: 91.5 [84-95]; Bupi: 76 [61-86]; BupiCloni: 84.5 [76-91]; and BupiEpi: 91 [56-92]).

Conclusion

The application of bupivacaine results in lower nerve blood flow, but does not induce relevant ischemia. Despite significant reductions in nerve blood flow, the addition of clonidine or epinephrine to bupivacaine had no significant impact on nerve tissue oximetry compared with bupivacaine alone. Nerve ischemia due to local anesthetics is not enhanced by the adjuvants clonidine or epinephrine.

Lower Extremity Near-infrared Spectroscopy After Popliteal Block For Orthopaedic Foot Surgery

Background:

Noninvasive measurement of cutaneous tissue oxygenation using near-infrared spectroscopy (NIRS) has become common in peri-operative care. Following institution of peripheral nerve blocks, neurovascular alterations in the blocked region have been described.

Objective:

The primary aim of this study encompassed the assessment of the influence of a popliteal block on changes in regional oxygen saturation (SrO₂), and the location of most prominent changes.

Method:

We conducted a prospective randomised controlled trial. Hundred twenty patients who received a popliteal block for foot surgery were included. Popliteal block was performed under echographic guidance. The patients were randomized in 3 groups according to the location of the SrO₂ electrodes on the legs. Bilateral SrO₂ measurements were performed simultaneously. SrO₂ in the operated leg and in the control leg was measured at baseline and 1, 5, 10, 15, and 30 minutes after the perineural injection. We quantified the evolution in SrO₂ by calculating over time the differences in SrO₂ values between the operated and control leg (=ΔSrO₂).

Results:

At 30 minutes, ΔSrO₂ increased significantly (p<0.05) at the plantar side of the foot (11.3% ± 2.9%), above the ankle (4.9% ± 1.3%) and the popliteal fossa (3.6% ± 1.2%).

Conclusion:

At 30 minutes after institution of the popliteal block, ΔSrO₂ was most prominent at the plantar side of the foot as compared with measurement performed above the ankle or under the knee.

Effects of prolonged ischemia on human skeletal muscle microcirculation as assessed by near-infrared spectroscopy

Near-infrared spectroscopy (NIRS) has been used to detect in vivo microvascular alterations by means of a vascular occlusion test. We sought to analyse by NIRS the microcirculatory profile of patients undergoing prolonged tourniquet-induced bloodless condition for extremity surgery, and compare the results with time of ischemia and comorbidities. We conducted a prospective observational study on 42 patients undergoing upper limb surgery. Regional anaesthesia was achieved and ischemia was induced by a tourniquet cuffed at 250 mmHg. The probe of a NIRS monitor (InSpectra 325, Hutchiston, USA) was placed on the brachial muscle, and muscle oxygen saturation (StO₂) was recorded continuously before anaesthesia, during and after surgery. The following variables were recorded: baseline StO₂, StO₂ desaturation slope during occlusion (dSlope, units/s), resaturation rate following ischemia (RR, units/s), hyperaemic peak (peak, units), and duration of the hyperaemic period following ischemia (hyperaemic time, s). Values of dSlope were similar among all patients. RR and hyperaemic time were significantly correlated with the duration of ischemia, but not with comorbidities [p = 0.007 CI (-35.64 to -13.1), and p < 0.001 CI (0.049-0.159), respectively]. Grouping patients by duration of ischemia (30, 60, or 90 min), we found a significant decrease in RR after 60 and 90 min (p < 0.001 and p = 0.03, respectively). Hyperaemic peak was lower in the 90 min group (83.9 ± 6.8 vs. 91.2 ± 5.7 %, p = 0.02) whereas the hyperaemic time was significantly increased (595 ± 136 vs. 429 ± 107 min, p < 0.001). Alterations of skeletal muscle microcirculation were correlated with the duration of ischemia, but not with comorbidities. We observed an initial impairment of the microcirculatory recovery at 90 min of ischemia.

Near-infrared spectroscopy: exposing the dark (venous) side of the circulation

The safety of anesthesia has improved greatly in the past three decades. Standard perioperative monitoring, including pulse oximetry, has practically eliminated unrecognized arterial hypoxia as a cause for perioperative injury. However, most anesthesia-related cardiac arrests in children are now cardiovascular in origin, and standard monitoring is unable to detect many circulatory abnormalities. Near-infrared spectroscopy provides noninvasive continuous access to the venous side of regional circulations that can approximate organ-specific and global measures to facilitate the detection of circulatory abnormalities and drive goal-directed interventions to reduce end-organ ischemic injury.

Changes in tissue oxygenation following caudal epidural blockade in infants and children

BACKGROUND

Adequate tissue oxygenation is required for effective white blood cell function and bactericidal activity. Decreased tissue oxygenation has been shown to be a risk factor for perioperative wound infections. Regional anesthetic techniques result in a functional sympathetic block and may increase tissue oxygenation. The purpose of the current study is to prospectively evaluate changes in tissue oxygenation using a non-invasive near-infrared spectroscopy (NIRS) device following caudal epidural block in infants and children.

METHODS

Following standard anesthetic induction and general anesthesia with an endotracheal tube or laryngeal mask airway, the NIRS sensors were placed on two sites. One sensor was placed at a site affected by the caudal block (lower extremity), and the other sensor was placed on the arm, a site unaffected by the caudal block (upper extremity). The NIRS value was recorded at baseline and then again at 15, 30, and 45 min after the block. The caudal block was performed, after anesthetic induction and NIRS sensor placement, using bupivacaine 0.25% with epinephrine 1 : 200,000 or ropivacaine 0.2% with epinephrine 1 : 200,000 at a dose of 1 ml · kg(-1). The inspired oxygen concentration after induction was held constant at 30%, and anesthesia was maintained with sevoflurane at 1 MAC. No other pharmacologic agents were administered.

RESULTS

Following the caudal epidural block, there was a statistically significant increase in the tissue oxygenation from the affected site. The NIRS value increased from a baseline of 83 ± 4 to 87 ± 3 at 15 min (P = 0.0001 vs baseline), 88 ± 4 at 30 min (P < 0.0001 vs baseline), and 87 ± 4 at 45 min (P < 0.0001 vs baseline). No change was noted on the unaffected site (upper extremity).

CONCLUSION

There was a statistically significant increase in tissue oxygenation as measured by NIRS following caudal anesthesia in infants and children. Although the magnitude of the change was less, this study confirms the results of previous studies in adults showing an increase in tissue oxygenation following regional blockade.