Ācārya Susruta has explained Trividha Karma in fifth chapter of Sūtrasthāna namely Agropaharaṇīya Adhyāya.

• त्रिविधं कर्म– पूर्वकर्म, प्रधानकर्म, पश्चात्कर्मेति; तद्व्याधिं प्रत्युपदेक्ष्यामः ||३||

According to him Trividha Karma are Pūrvakarma, Pradhānakarma and Paścātkarṇa

In the Ḍalhaṇa ṭīkā of the above sloke it is mentioned as below

• लङ्घनादि विरेकान्तं पूर्वकर्म व्रणस्य च|

          पाटनं रोपणं यच्च प्रधानं कर्म तत् स्मृतम्|

          बलवर्णाग्निकार्यं तु पश्चात्कर्म समादिशेत्

Here he mentions Trividha Karma in the context of Vrana

• Pūrvakarma – Laṅghana, Dīpana, Pācana, Snehana, Svedana, Vamana, Virecana
• Pradhānakarma – Pāṭana and of Vrana
• Paścātkarma – Bala, Varna, Jaṭharāgni Vardhana karma

In the continuation of the above sloka of Ḍalhaṇa he explains Trividha karma which is relevant to Pañcakarma

• अन्ये तु संशोध्यस्य पाचनस्नेहनस्वेदनानि पूर्वकर्म,

          वमनविरेचनबस्तिनस्यसिरामोक्षणानि प्रधानं कर्म,

          पेयाद्यन्नसंसर्जनं पश्चात्कर्म

Here Trividha karma means

• Pūrvakarma – Pācana, Snehana, Svedana
• Pradhānakarma – Vamana, Virecana, Basti, Nasya, Raktamokṣa. So basically all the Pañcakarma is mentioned here
• Paścātkarṇa – Peyādi Samsarjana Krama

There is one more opinion in the same Ḍalhaṇa sloka as below

• अपरे तु चयादीनां पूर्वरूपान्तानामातङ्कोत्पत्तेः प्राग्यत् क्रियते तत् पूर्वकर्म,

आतङ्कोत्पत्तौ यत् तत् प्रधानं कर्म, निवृत्तातङ्कस्यानुबन्धोपचरणाय यत् तत् पश्चात्कर्म|

Here the explanation is based on the Karma which has to be done in

• Pūrvakarma – sañcaya, Prakopa, Prasara, Sthānasaṃśraya and Pūrvarūpa avasthā.
• Pradhāna karma – After Roga utpatti / Vyakta avasthā
• Paścāt karma – After Roga nivṛtti, and for Roga Apunarbhāva hetu

Before the actual process begins the body should be prepared with certain procedures.

पाचनैर्दीपनैः स्नेहैस्तान् स्वेदैश्च परिष्कृतान्||

शोधयेच्छोधनैः काले यथासन्नं यथाबलम्|

In the Chapter Doṣa upakrāmaṇīya Adhyāya in Aṣṭāṅga Hṛdaya Sūtra Sthāna Vāgbhaṭa explains the treatment of Āma. Here is explains the Karma that has to be followed before going for Śodhana

He says Āma doṣa has to be modified by means of oleation using Snehas prepared with drugs which are Pācana/ Digestive and Dīpana / Carminative followed by Svedana or Sudation. Then they have to be expelled out by means of appropriate Śodhana therapy through the proximal route in proper time, considering the strength of the patient.

• Pācana – Āma Pācana – Digestion of Āma
• Dīpana – Agni Dīpana – Enhancing the digestive fire
• Snehana – Internal and External application of Sneha
• Svedana – Sudation

Dīpana – Pācana

पचेत् न आमं वह्निकृच्च दीपनं तत् यथा मिशि

पचत्यामं न वह्निं च कुर्यात पाचनं

नागकेसरवत् विद्यात् चित्रको दीपनपाचन

Dīpana drugs does not digest Āma but only increases Agni. Example is Misi or Fennel Seeds

Pācana Drugs helps to digest the Āma but will not increase Agni. Example is Nāgakesara or Mesua ferra. The drug Citraka or Plumbago zeylanica does both Dīpana and Pācana.

Once the Agni is increased and Āma is digested body is ready for Snehana and Svedana

Snehana

स्नेहोऽनिलं हन्ति मृदूकरोति देहं मलानां विनिहन्ति सङ्गम्||७||

Oleation therapy alleviates aggravated Vāyu, softens the body and disintegrates the adhered morbid material in the channels of circulation

Svedana

स्निग्धस्य सूक्ष्मेष्वयनेषु लीनं स्वेदस्तु दोषं नयति द्रवत्वम्|८|

In the person who has undergone oleation therapy fomentation liquifies the adhered morbid materials in the fine channels of the body

स्नेहक्लिन्नाः कोष्ठगा धातुगा वा

स्रोतोलीना ये च शाखास्थिसंस्थाः|

दोषाः स्वेदैस्ते द्रवीकृत्य कोष्ठं

नीताः सम्यक् शुद्धिभिर्निर्ह्रियन्ते|

The doṣas which are based in Koṣṭha, dhātus or in latent srotases or else based at Śākhās or Asthi causing diseases; when subjected to Sneha procedures are made Klinna or Slimy are to be liquified by Svedana or sudation and thus brought to Koṣṭha and then eliminated through the proximal route by judicious use of Śodhana procedures.

Pradhāna karma includes Vāmana, Virecana, Āsthāpana Vasti, Aṇuvāsa Vasti and Nasya according to Caraka school of thought and Vāmana, Virecana, Vasti, Nasya and Raktamokṣaṇa according to Suśruta school of thought. After proper Pūrvakarma the doṣas which are brought from Śākhā to Koṣṭha should be eliminated through the nearest route.

Vāmana (Therapeutic Emesis)

तत्र दोषहरणमूर्ध्वभागं वमनसञ्ज्ञकम् 

Vāmana is defined as the process by which the doṣas are eliminated through the Ūrdhva bhāga.

ऊर्ध्वं मुखेन दोषनिर्हरणं भजत इति ऊर्ध्वभागम्|

Cakrapāṇi mentions that Ūrdhvabhāga should be considered as Ūrdhva mukha or mouth.

Vāmana Karma, the first measure amongst Pañcakarma, has been considered as the best line of treatment of Kaphaja Roga.

Virecana (Therapeutic Purgation)

तत्र दोषहरणमूर्ध्वभागं वमनसञ्ज्ञकम्, अधोभागं विरेचनसञ्ज्ञकम्

In continuation to the above śloka of Caraka the definition of Virecana is also explained in Kalpa Sthāna.

Virecana is defined as the process by which the doṣas are eliminated through the Adhobhāga.

अधो गुदेन दोषनिर्हरणं भजत इति अधोभागम्|

Cakrapāṇi mentions that Adhobhāga should be considered as guda or anal route.

In Virecana Karma the medicine administered through the oral route gets digested and acts in the elimination of Pitta. Virecana is the prime modality of treatment for Pitta doṣa nirharaṇa.

Vasti Karma (Enema therapy)

The administration of medicated herbal decoctions or kvātha along with mākṣika or honey, Saindhava or rock salt, sneha or oils, kalka or medicinal paste (Nirūha Vasti) or medicated oils (Sneha Vasti) through gudā mārga to act in the predominant site of Vāta i.e., Colon is known as Vasti Karma or Enema therapy.

नाभिप्रदेशं कटिपार्श्वकुक्षिं गत्वा शकृद्दोषचयं विलोड्य ॥४०॥

संस्नेह्य कायं सपुरीषदोषः सम्यक् सुखेनैति च यः स बस्तिः [५] ।४१। Ch.Si. 1/41

The procedure in which the drug prepared is administered through anal canal which reaches upto nābhi pradeśa, kaṭi pārśva and kukṣi , churns the accumulated doṣa and purīṣa, spreads the unctuousness (Potency of the drugs) all over the body and easily comes out along with the churned purīṣa and doṣas is called बस्ति. 

Nasya Karma (Nasal Instillation of Medicine)

Nasal administration of medication is called Nasya. The nose is the gateway to the head. Nasya Karma is important among Pañcakarma as it is useful in the management of Ūrdhvajatru gata rogas.

ऊर्ध्वजत्रुविकारेषु विशेषान्नस्यमिष्यते|

नासा हि शिरसो द्वारं तेन तद्व्याप्य हन्ति तान्||१||

Medicine instilled through nose spreads throughout the Śiras and help in the evacuation of Doṣa and thereby pacifying the diseases.

Raktamokṣaṇana Karma (Blood Letting therapy)

Removing vitiated blood from the body is called as Raktamokṣaṇana. It is used in the management of Rakta and Pittaja Rogas. It is classified into Śastra visrāvaṇa and Aṇu Śastra Visrāvaṇa. The former is again classified into Pracchāna and Sirāvyadha while the latter is classified into Śṛṅga, Jalaukā avacāraṇa, Alābu and Ghaṭī yantra.

After the Śodhana therapy the Agni and the strength of the body becomes weak, so as to restore this a specific diet regulation is to be carried out. They bring the body back to normalcy. This mainly includes Saṃsarjana Krāma.

• संशोधनास्रविस्रावस्नेहयोजनलङ्घनैः||४५||

          यात्यग्निर्मन्दतां तस्मात् क्रमं पेयादिमाचरेत्|

• वमितश्च विरिक्तश्च मन्दाग्निश्च विलङ्घितः|

          अग्निप्राणविवृद्ध्यर्थं क्रमं पेयादिकं भजेत् [१] ||५७||

Both of the above Ślokas by Vāgbhaṭa and Caraka conveys similar meaning about Peyadi Saṃsarjana Krama. In the patients whose digestive power becomes dull by purificatory therapies, bloodletting, unction, fasting; peyadi krama should be observed. By following the specific diet schedule ie; Peya, Vilepī, akṛta and kṛta – Yūṣa and Māṃsa rasa the Agni and the Prāṇa of the patient will become normalized.

In this context Vāgbhaṭa has explained a similie

यथाऽणुरग्निस्तृणगोमयाद्यैः

सन्धुक्ष्यमाणो भवति क्रमेण|

महान् स्थिरः सर्वपचस्तथैव

शुद्धस्य पेयादिभिरन्तराग्निः||३०||

By observing the Peyadi Krama after Śodhana the digestive fire will gradually increase, become steady and capable of digesting everything; just like a spark of fire slowly  incinerates grass, cow dung and become a larger fire that is capable of incinerating even heavy wood logs.

Types of Saṃsarjana Krama

• Peyadi Saṃsarjana Krama
• Tarpaṇadi Saṃsarjana Krama
• Rasa Saṃsarjana Krama