Ultrasound examination of the sciatic nerve at the anterior thigh in obese patients

Identification of interfascial plane using injection pressure monitoring at the needle tip during ultrasound-guided TAP block in cadavers

INTRODUCTION

Consistency in needle tip positioning within interfascial planes while performing infiltrative blocks under ultrasound guidance can be difficult. The exact determination of such planes may beyond the physical limits of common ultrasound machines. Aim of this pilot study was to understand if real-time continuous injection pressure monitoring at the needle tip, combined with ultrasound guidance, can help to immediately and consistently identify an interfascial plane needle tip placement.

METHODS

We performed four ultrasound-guided transversus abdominis plane (TAP) blocks on fresh cadaver using a modified conventional peripheral nerve block needle. The sensing needle contains Fabry-Perot miniaturized pressure sensor floating at the needle tip, connected to a measuring unit via an optical fiber. Injection-pressure measured at the needle tip was continuously recorded, while the needle was advanced toward the target and 0.9% saline was continuously injected via an electronic pump.

RESULTS

A recognizable, recurrent three-peaks injection pressure pattern was identified, while advancing the needle through the abdominal wall, the pressure peaks being identified with the needle to fasciae contact. In four different blocks, a total of 12 peaks and 12 troughs were identified. The mean injection pressure (95% CI) of the peaks varied substantially from the mean injection pressure of the troughs, from 119.55 kPa (95% CI 87.3 to 151 kPa) to 30.99 kPa (95% CI 12.5 to 47.5 kPa), respectively. The peaks (troughs) arose from reproducible pressure curves and were related to the needle tip encountering the muscle fasciae.

CONCLUSION

The identified injection pressure pattern, together with ultrasound image, may help in determine real-time the needle tip position, while performing a TAP block.

The effects of body mass index on postoperative pain in patients undergoing thoracic paravertebral block after video-assisted thoracoscopic surgery: A retrospective analysis

Aim: Postoperative pain is an important problem in patients undergoing video-assisted thoracic surgery (VATS). Thoracic paravertebral block (TPVB) is among the commonly used techniques for pain control after VATS. Despite the analgesic methods applied, the desired level of pain control can not be achieved in all patients. Therefore, clinicians and researchers are interested in factors affecting postoperative pain. One factor is the relationship between postoperative pain and body mass index (BMI). Although it has been reported that acute or chronic pain is more common in the general population with a BMI, the relationship between postoperative pain and BMI is still controversial. This study aims to investigate the effects of BMI on postoperative pain in patients who underwent TPVB in the treatment of pain after VATS. Material and Method: Patients who had elective VATS and TPVB were included in the study. Patients who underwent TPVB with ultrasonography (USG) and postoperative intravenous (iv) morphine patient-control-analgesia (PCA) for postoperative analgesia were divided into three groups according to BMI. Group-I BMI: 18-24.99 kg/m2, Group-II BMI: 25-29.9 kg/m2, Group-III BMI: 30-40 kg/m2. Results: 146 patients were included in the study. There was no significant difference between the postoperative 30th minute, 1st hour, 6th hour, 12th hour, and 24th-hour VAS values of the patients in Group-I, Group-II, and Group-III. There was no statistically significant difference in terms of morphine consumption, additional analgesic requirement, and complications in all three groups. Conclusion: It was determined that there was no relationship between BMI and postoperative pain scores in the first 24 hours in patients who underwent TPVB after VATS. In addition, it was determined that postoperative morphine consumption and additional analgesic needs were not associated with BMI. Effective pain control can be achieved in all patients, regardless of BMI, with effective peripheral nerve blocks and analgesics using practical imaging techniques such as USG.

Comparison of general versus isolated regional anesthesia in total shoulder arthroplasty: A retrospective propensity-matched cohort analysis

BACKGROUND

Intraoperative anesthetic typically consists of either general anesthesia (GA) or isolated regional anesthesia (RA).

METHODS

A retrospective propensity-matched cohort analysis on patients undergoing TSA was performed to determine differences between GA and RA in regard to patient population, complications, LOS and hospital readmission.

RESULTS

4158 patients underwent TSA with GA or isolated RA. Propensity-matching resulted in 912 patients in each cohort. RA had lower overall in-hospital complications and greater homebound discharge disposition with lower 90-day readmission rates than GA.

CONCLUSION

After TSA, isolated RA was associated with lower in-hospital complications, readmission rates and odds of hospital readmission than GA.

Regional anesthesia and obesity

PURPOSE OF REVIEW

Worldwide, the number of overweight and obese patients has increased dramatically. As a result, anesthesiologists routinely encounter obese patients daily in their clinical practice. The use of regional anesthesia is becoming increasingly popular for these patients. When appropriate, a regional anesthetic offers advantages and should be considered in the anesthetic management plan of obese patients. The following is a review of regional anesthesia in obesity, with special consideration of the unique challenges presented to the anesthesiologist by the obese patient.

RECENT FINDINGS

Recent studies report difficulty in achieving peripheral and neuraxial blockade in obese patients. For example, there is an increased incidence of failed blocks in obese patients compared with similar, normal weight patients. Despite difficulties, regional anesthesia can be used successfully in obese patients, even in the ambulatory surgery setting.

SUMMARY

Successful peripheral and neuraxial blockade in obese patients requires an anesthesiologist experienced in regional techniques, and one with the knowledge of the physiologic and pharmacologic differences that are unique to the obese patient.

Three-dimensional ultrasound-assisted popliteal catheter placement revealing aberrant anatomy: implications for block failure

BACKGROUND

The current means of introducing continuous sciatic catheters include nerve stimulation, with or without catheter stimulation techniques. More recently, ultrasound has been utilized to facilitate catheter placement.

METHODS

This case represents a stimulating catheter-guided continuous block facilitated by three-dimensional ultrasound, which revealed aberrant anatomy with proximal and wide bifurcation of the sciatic nerve with implications for block failure.

RESULTS

Before ultrasound imaging secondary failures were attributed to catheter misplacement or dislodgement.

CONCLUSION

Because of this case observation, our current practice is to use ultrasound confirmation of the bifurcation of the nerve of all popliteal catheter placements, particularly catheters placed in patients having ambulatory procedures to prevent secondary failure of catheters at home.