Anaesthetic consideration for robotic nipple sparing mastectomy

摘要

Sir, We report perioperative anaesthetic concerns related to the first robotic nipple sparing mastectomy with breast expander implant (BEI). This relatively new surgical technique provides satisfactory surgical results, less pain and better patient compliance in addition to hidden scar.[1] Toesca et al. who pioneered this technique have highlighted the surgical aspects. General anaesthesia is required similar to other robotic surgeries with a few variations as highlighted below. The position of the robotic cart in relation to the anaesthesia workstation is crucial for smooth conduct of surgery. The patient's cart was placed on contralateral side of the operation [Figure 1] with robotic arms near parallel to the floor [Figure 2]. As our workstation was fixed to the pendant, it was kept towards the foot end to provide ample working space. The position of anaesthesia workstations is optional until it does not interfere in surgical field, and still we recommend to keep it at foot end. This layout requires long breathing circuit (two standard circuits of 180 cm connected in series) and a 100 cm extension line connected to intravenous (IV) infusion set, as the cannula is not easily accessible in docked position, additional IV in foot is desirable as a precautionary measure.Figure 1: Robotic patient cart positioned on the contralateral side of the operation and the robotic arms come above the patient for dockingFigure 2: Robotic arms docked through patient access system device which are aligned nearly parallel to the floorInitially, the patient was positioned supine till resection of breast tissue and BEI insertion and later semi-reclined for the assessment of breast symmetry. We suggest pelvic straps and foot restrains to be applied to prevent sliding down of the patient in semi-recline position. Wide-opened elbow is a prerequisite for surgical access which can be achieved by placing the patient supine at the edge of table with the ipsilateral upper limb sagging below it [Figure 3], and the contralateral limb resting by the side of the patient. Such a position could lead to brachial plexus injury due to gravitational pull and stretching on the unsupported limb, though Toesca et al. have not reported any nerve injury.[2] Placing a silicone gel pad between the edge of the table and arm [Figure 3] prevents brachial plexus and pressure injury on the medial aspect of the operative limb. Resting the ipsilateral hand on pelvis with adhesive tapes also supports limb and prevents overstretching of limb. Inserting a small scaffold from the edge of table underneath the elbow may be helpful to reduce the stretching force on the brachial plexus.Figure 3: Silicone gel pad placed underneath the sagging left upper limb with wide-opened elbow for docking of robotic armsSubcutaneous pocket was lifted to insert single patient access system device [Figure 4], through which robotic arms were docked. CO2 was insufflated at 2–7 mmHg with flow rate at 20 L/min to keep the breast flap elevated, which could cause hypercarbia and post-operative surgical emphysema. Limiting insufflation pressure up to 6 mmHg is sufficient to maintain the surgical space while preventing significant CO2 absorption through the subcutaneous tissue.[3] CO2 insufflation in closed body cavities usually necessitates change in ventilator settings, but in spite of not changing the ventilator settings, no post-operative surgical emphysema and capnothorax was observed.Figure 4: Patient access system device fitted into the subcutaneous pocket of breast flap, allowing camera and other robotic instrument to work through a small incisionThermal injury of flap due to fibre-optic light and heated fumes from electrocautery[4] is prevented by intermittent evacuation of CO2, smoke and cooling of the flap with wet gauze. Variable heat conductance in the body tissue (lower conductance in adipose tissue as compared to muscle and skin) further protects against thermal injury.[56] Pectoral nerve blocks