Why need a surgeon? You have a scalpel, antiseptic, ketamine, let's go!
If you want specific things done in a session involving spirits, you usually need a spiritworker.
What exactly are these spirits? What is purple medicine?
From wiki page on Ayahuasca:
DMT admixtures:
Psychotria viridis (Chacruna)[11] – leaves
Diplopterys cabrerana (Chaliponga, Chagropanga, Banisteriopsis rusbyana)[11] – leaves
Psychotria carthagenensis (Amyruca)[11] – leaves
Mimosa tenuiflora (M. hostilis) - Root bark
Other common admixtures:
Justicia pectoralis[9]
Brugmansia (Toé)[11]
Nicotiana rustica[11] (Mapacho, variety of tobacco)
Ilex guayusa,[11] a relative of yerba mate
Common admixtures with their associated ceremonial values and spirits:
Ayahuma[11] bark: Cannon Ball tree. Provides protection and is used in healing susto (soul loss from spiritual fright or trauma).
Capirona[11] bark: Provides cleansing, balance and protection. It is noted for its smooth bark, white flowers, and hard wood.
Chullachaki caspi[11] bark (Brysonima christianeae): Provides cleansing to the physical body. Used to transcend physical body ailments.
Lopuna blanca bark: Provides protection.
Punga amarilla bark: Yellow Punga. Provides protection. Used to pull or draw out negative spirits or energies.
Remo caspi[11] bark: Oar Tree. Used to move dense or dark energies.
Wyra (huaira) caspi[11] bark (Cedrelinga catanaeformis): Air Tree. Used to create purging, transcend gastro/intestinal ailments, calm the mind, and bring tranquility.
Shiwawaku bark: Brings purple medicine to the ceremony.
Uchu sanango: Head of the sanango plants.
Huacapurana: Giant tree of the Amazon with very hard bark
Bobinsana: Mermaid Spirit. Provides major heart chakra opening, healing of emotions and relationships.