The number of outpatient surgery procedures is increasing, and the outpatient surgery centers (or Ambulatory Surgery Centers, ASC) require a quick turnover to satisfy the high number of patients who require surgery.
The goal in ambulatory surgery anesthesia is to reduce the complications such as postoperative pain, opioid requirements, postoperative nausea and vomiting, along with functional recovery. The use of peripheral nerve blocks (PNBs), alone or combined with general anesthesia, is the best choice to achieve a postoperative pain control. By using the PNBs it is possible to reduce the time-to-discharge after ambulatory orthopedic surgeries.
The volume and dosage of the local anesthetic (LA) and the concurrent use of adjuvants can modify the sensory and motor offset time of the single-shot PNBs. The duration of the postoperative analgesia is up to 24 hours by using a combination of long-acting LA and adjuvants.
It has been demonstrated that ultrasound (US) guidance improves block success, onset, quality, and decreases the local anesthetic requirements if compared to peripheral nerve stimulation (PNS). US guidance is nowadays the technique of choice for PNBs and continuous peripheral nerve blocks (CPNBs) in association with PNS. US guidance also improves the success rate and speeds up the catheter placement for continuous peripheral nerve blocks (CPNBs).
Whilst no data demonstrated the elimination of nerve injury with USG, it has been demonstrated instead a reduction of local anesthetic toxicity incidence.
CPNBs may be a good choice for the postoperative pain control of the outpatient, but they need to be selected and educated. Currently, the CPNBs are losing popularity because of their cons: time consumption due to the positioning, dislocation, LAST. However, the CPNBs have been demonstrated to provide a superior analgesia compared to the opioid based analgesia and single injection PNBs techniques.
The fascial blocks are suitable for postoperative pain control in general surgery.
Regarding ambulatory breast surgery, the Pectoral Nerve Blocks (PECS) I, the PECS II and the Serratus Plane Block (SPB) are a US guided techniques for postoperative pain control in outpatients. These techniques aim to block the pectoral, intercosto-brachial, the third to sixth intercostals and the long thoracic nerves. They may provide good analgesia during and after breast surgery.
For the outpatient inguinal hernia repair, the US-guided Transversus Abdominis Plane Block (TAPB) along with iliohypogastric and ilioinguinal nerve blocks is an option for anesthesia or postoperative pain control. Catheters for prolonged analgesia after surgery could also be used.
Regarding orthopedic surgery in the outpatient setting, the most commonly performed technique to provide anesthesia-analgesia for shoulder procedures is the interscalene block. The injection of LA within the interscalene groove between the anterior and middle scalene muscles blocks the C5 and C6 roots, forming the upper trunk of the brachial plexus, and the C7 root forming the middle trunk of the brachial plexus. This block provides a reduction of opioid consumption after shoulder surgery as a consequence of complete analgesia. Common side effects of the interscalene block are the ipsilateral phrenic nerve block and the Bernard-Horner syndrome. The patient should be observed in the post-anesthesia care unit for complaints of subjective shortness of breath or respiratory compromise before being discharged home. US guidance also allow the supraclavicular approach to brachial plexus block.
The supraclavicular approach to the brachial plexus provides a similar analgesia to the interscalene block but often lacks the upper skin surface of the shoulder supplied by the cervical plexus. Therefore, for shoulder surgery, the interscalene and supracavicolar blocks allow a good analgesia and anesthesia.
The infraclavicular block can be used for surgeries of the elbow, forearm, wrist, and hand. The infraclavicular block is phrenic nerve-sparing. This is the last site where the local anesthetic can be injected before the musculocutaneous and axillary nerves emergence from the brachial plexus. A catheter for CPNBs could be placed on this site. In addition, these catheters are well tolerated by patients and an occlusive dressing keeps them safely in place. When compared to the supraclavicular approach, infraclavicular catheters provide a superior analgesia for elbow procedures or below.
The axillary nerve block, or axillary approach to the brachial plexus, is a widespread block for ambulatory surgery because of its long history, knowledge and ease of compressibility if vascular puncture occurs.
Regarding the inferior limb, to provide anesthesia and postoperative analgesia after minor (knee arthroscopy) and major knee surgery (arthroscopic anterior cruciate ligament (ACL) reconstruction) femoral nerve block (FNB) is most frequently performed. The femoral nerve provides innervation to the hip, thigh, knee, and the antero-medial surface of the leg. It has also been reported to provide effective rescue analgesia after ambulatory hip arthroscopy. The literature supports the analgesic benefits of single-shot and continuous FNB for arthroscopic ACL reconstruction. However, an increased risk of falls associated with FNB has been reported.
In the latest years, the adductor canal block (ACB) and the femoral triangle block (FTB) are increasingly being performed for post-operative analgesia. These blocks improve analgesia after minor and major knee surgery without a significant quadriceps motor block.
The sciatic nerve provides innervation to the hip, thigh, knee, leg and foot. It is usually blocked at the hip level for thigh and knee surgeries, or at the popliteal fossa for leg, ankle and foot surgeries. Identification of the common sciatic nerve and its bifurcation into the tibial and common peroneal nerve trunks is facilitated with USG compared with the PNS for both single injection and CPNBs.
The ankle block is performed for foot ambulatory surgery. USG further improves the efficacy of this block.
Spinal Spinal anesthesia is the oldest regional anesthesia technique. Even so, the neuraxial block is not the main choice for the outpatients if surgery on the lower abdomen or limbs is performed (Anaesth Crit Care Pain Med. 2018 Jun;37(3):239–244. doi: 10.1016/j.accpm.2016.12.002. Epub 2016 Dec 19. Spinal anaesthesia in outpatient and conventional surgery: A point of view from experienced French anaesthetists. Fuzier R1, Aveline C2, Zetlaoui P3, Choquet O4, Bouaziz H5; members of the i-ALR Association). However, in the latest years, two new shorter-acting LA have been introduced: prilocaine and chloroprocaine. The use of a non-long acting LA allows a faster motor recovery and a reduced urinary retention, making this technique preferable to PNBs in some situations.
The local anesthetic systemic toxicity (LAST) is a complication of LA injections and would impair the outpatients discharge.
There could also be a neural local anesthetic toxicity when a high volume of concentrated LA is injected. In this situation a residual sensitive and motor block could impair the patient discharge.
In conclusion, there are several regional anesthesia techniques that can be performed in the outpatients. However, proficiency in these techniques is advisable if them are to be executed in the outpatient, because some have a slow learning curve and benefits and risks have to be considered.
Summary Regional anesthesia provides significant improvements in postoperative analgesia and quality of recovery for ambulatory surgery. The use of PNBs and fascia blocks allow a rapid recovery obtaining a faster discharge after ambulatory surgery. The common element in ambulatory surgery is to get rid of complications like postoperative pain, opioid applications, postoperative nausea and retch and reduction of the likelihood of functional recovery. Moreover, the usage of CPNB techniques improves these benefits beyond the duration of single-injections. USG has significantly increased the success, safety and efficiency of regional anesthesia. Regional anesthesia really gained a primary importance role in obtaining the best patient outcome, alone or in association with general anesthesia after the ambulatory surgery.
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