The NG tube answer is "It depends."
Since the LPN is operating under the supervision of an RN, and the RN is ultimately responsible for the outcome (and her/his license is on the line), the decision remains with the RN whether a certain task will be delegated or not.
As for where you will find clear-cut distinctions, all you can do is check the rules and regulations at the BON and at your facility. Sometimes there are facility/unit protocols, under which trained individuals are allowed to do things that would normally be out of their scope of practice under the protocol.
Here is the link to the New Jersey Board of Nursing.
Under Regulations, see 13:37-6.2 Delegation of Selected Nursing Tasks, which reads:
"13:37-6.2 Delegation of selected nursing tasks
(a) The registered professional nurse is responsible for the nature and quality of all nursing care including the assessment of the nursing needs, the plan of nursing care, the implementation, and the monitoring and evaluation of the plan. The registered professional nurse may delegate selected nursing tasks in the implementation of the nursing regimen to licensed practical nurses and ancillary nursing personnel. Ancillary nursing personnel shall include but not be limited to: ***** ***** attendants and technicians.
(b) In delegating selected nursing tasks to licensed practical nurses or ancillary nursing personnel, the registered professional nurse shall be responsible for exercising that degree of judgment and knowledge reasonably expected to assure that a proper delegation has been made. A registered professional nurse may not delegate the performance of a nursing task to persons who have not been adequately prepared by verifiable training and education. No task may be delegated which is within the scope of nursing practice and requires:
1. The substantial knowledge and skill derived from completion of a nursing education program and the specialized skill, judgment and knowledge of a registered nurse;
2. An understanding of nursing principles necessary to recognize and manage complications which may result in harm to the health and safety of the patient.
(c) The registered professional nurse shall be responsible for the proper supervision of licensed practical nurses and ancillary nursing personnel to whom such delegation is made. The degree of supervision exercised over licensed practical nurses and ancillary nursing personnel shall be determined by the registered professional nurse based on an evaluation of all factors including:
1. The condition of the patient;
2. The education, skill and training of the licensed practical nurse and ancillary nursing personnel to whom delegation is being made;
3. The nature of the tasks and the activities being delegated;
4. Supervision may require the direct continuing presence or the intermittent observation, direction and occasional physical presence of a registered professional nurse. In all cases, the registered professional nurse shall be available for on-site supervision.
(d) A registered professional nurse shall not delegate the performance of a selected nursing task to any licensed practical nurse who does not hold a current valid license to practice nursing in the State of New Jersey. A registered professional nurse shall not delegate the performance of a selected nursing task to ancillary nursing personnel who have not received verifiable education and have not demonstrated the adequacy of their knowledge, skill and competency to perform the task being delegated.
(e) Nothing contained in this rule is intended to limit the current scope of nursing practice.
(f) Nothing contained in this rule shall limit the authority of a duly licensed physician acting in accordance with N.J.S.A. 45:9-1 et seq."
Schuyler, MSN, RN. ANP