**5. Lateral decubitus**

52 Modern Arthroscopy

ultrasound transducer is employed. It may be difficult to maintain good ventilation in obese patients and to use the neurostimulator to find the brachial plexus in the different supraclavicular approaches. The preanesthesia visit is a good time to perform this exploration. Chronic lung disease may be a relative contraindication to performing a bilateral interscalene block, since phrenic nerve block exacerbates the poor respiratory function in such patients. In such cases additional studies may be necessary, such as chest RX and basic

We explore the contralateral arm to see determine whether the patient has a clear vein network channel for peripheral venous administration, or whether an alternative route of administration will be required. While the patient must fully informed of the technique they are to undergo, if told "a needle will be inserted into your neck" their levels anxiety are likely to rise. However, a correct explanation of the technique, starting at the pre-operative visit and continuing up to and during the procedure, along with adequate sedation, will significantly increase the patient´s satisfaction with the technique, as well as their confidence

A blood analysis including blood counts and basic clotting biochemistry must be performed, particularly for more invasive surgical procedures such as prosthetic glenohumeral joint or proximal humerus fractures. Arthroscopic procedures themselves do not involve bleeding. A severe impairment of clotting is an absolute contraindication for performing the regional block technique, although it can be partially permissive if taking into account the benefit/risk in those patient at the limits of normality, and particularly when ultrasoundguided block is performed by an expert. We also investigate factors or conditions that potentially increase the risk of post-operative nausea and vomiting in the patient, which

the patient must be informed of the pain they may experience after the surgical procedure, as well as of the various analgesic strategies available. of and understand the information provided during the pre-anesthesia visit, including the possible associated complications and setbacks, and they must provide informed consent for the anesthetic techniques that

Whether in the operating theatre or in an alternative location approved to perform the peripheral nerve block, access is required to a peripheral vein in the arm contralateral to the surgery at least. Where premedication with benzodiazepines or other hypnotics is required, it is desirable to provide the patient with a supplementary source of oxygen in the form of a low flow nasal cannula or face mask (11). Shoulder As shoulder arthroscopy does not involve a large degree of fluid loss, a small venous line will suffice (a 20G needle should be

Basic patient monitoring principles should be applied, including circulatory parameters such as heart rate and non-invasive blood pressure, partial oxygen saturation, continuous electrocardiogram leads II (for better evaluation of rhythm disturbances) and V5 (for better assessment of ST segment changes and repolarization). In cases where the patient receives mechanical ventilation or spontaneous ventilation through a supraglottic airway device, FiO2 and fractional exhaled CO2 should be continuously monitored, along with basic ventilation parameters (tidal volume, respiratory rate, index I:E, airway pressure and PEEP if applicable). The patient´s temperature should also be controlled systematically, given the

adequate). However, fluid deficits due to pre-operative fasting should be calculated.

may require prophylactic drugs or adaptation of the anesthetic technique.

tests of respiratory function (*e.g.,* spirometry).

**4. General considerations during surgery** 

considerable loss of heat that can occur during surgery.

in the anesthesiologist.

may be employed.

Proposed This method was first proposed by Wiley and Older (12), whereby the patient is positioned with a lateral tilt, leaving the arm exposed. No traction should be used, and the position of flexion and adduction of the arm should allow easy penetration of the shoulder joint.

In order to obtain greater diastasis of the joint, Andrews and Carson (13) positioned the arm at about 70º of abduction and 15º of flexion, with adequate longitudinal tension, although this may lead to overstretching the neurovascular structures (Figure 1). Different drivelines can be applied to the upper limb but the weight applied to traction should under no circumstances exceed 4-6 kg. Moreover, as the drive can induce ischemic stroke, traction for more than 2 hours should be avoided. Paulos (14) reported 30% transitional neuroapraxia after shoulder arthroscopy. Before traction, the upper limb should be slightly rotated internally at the elbow to reduce the tension on glenohumeral ligaments, thereby augmenting the joint space. In preparing the operating room is important to place the anesthesia machine beside the surgical bed to provide the surgeon with sufficient room to move and operate (Table 1).

Fig. 1. Lateral decubitus position.

Anesthesia for Arthroscopic Shoulder Surgery 55

The mMaintaining normothermia and preventing heat loss by the patient during surgery is essential due to the large amount of fluid infused into the joint. Hypothermia slows patient recovery. Indeed, shivering increases tissue oxygen demand and decreases cardiac output, thereby hindering proper oxygen and nutrient exchange to tissues, leading to acidosis. After surgery, the material that covers the patient is usually wet and cool, which also makes the patient cool. Using waterproof materials is effective, as is good continued aspiration of the instilled fluid. Furthermore, mechanical ventilation lowers the temperature by using a cold gas. Fluid heating systems and convection heating elements are usually effective in this kind

The interscalene and supraclavicular approaches to the brachial plexus (above the clavicle or proximal), have proven effective and safe for anesthesia and post-operative analgesia in arthroscopic shoulder surgery. Recently, a new safe and effective approach to arthroscopic shoulder surgery was advocated, blocking the suprascapular nerve and axillary nerve, although this is a preliminary study (15). The parascalene approach is also thought to offer safe and effective anesthesia for these procedures, as well as a unique benefits in the

The intercostobrachial nerve comes from the thoracic nerve roots T1-T2 and it is responsible for the sensitivity of the anteromedial aspect of the arm. Since some techniques do not block the supraclavicular nerve, this is achieved with a subcutaneous wheel and 3-5 ml of local axillary anesthetic, superficial to the area of palpation of the axillary artery (Figure 3).

Fig. 2. Representation of the Beach chair position

of surgery for prophylaxis of hypothermia.

treatment of acute postoperative pain (16).


Table 1. Patient position
