Summary & Overview

HCPCS G9645: Smoking Prior to Anesthesia on Day of Procedure

HCPCS Level II code G9645 documents patients who did not abstain from smoking prior to anesthesia on the day of surgery or procedure. This perioperative assessment code captures tobacco or nicotine use reported or observed on the day of anesthesia and is relevant to anesthetic planning and risk discussion. Nationally, documenting pre-anesthesia smoking status can affect clinical decision-making, airway management, and informed consent processes.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of the code’s clinical context, typical sites of service, and how payers commonly approach coverage and documentation requirements. The publication also summarizes common modifiers associated with anesthesia and perioperative service lines and highlights where data is not available in the input.

This summary provides clinicians, billing professionals, and policy analysts with a concise reference to the code’s purpose, typical use cases in hospital and ambulatory surgical settings, and the payers most relevant to nationwide billing and policy considerations. Data not available in the input includes specific associated taxonomies, ICD-10 diagnosis links, and payer-specific reimbursement rates.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicareG9645HCPCS Level IIpreoperative assessmentanesthesiasmokingperioperative careambulatory surgeryhospital billing

Billing Code Overview

HCPCS Level II code G9645 indicates patients who did not abstain from smoking prior to anesthesia on the day of surgery or procedure. This code is used to document instances in which a patient reported or was observed to have used tobacco or nicotine products on the day of anesthesia, potentially affecting perioperative management.

Service type: Perioperative assessment related to anesthesia readiness and risk stratification
Typical site of service: Hospital or ambulatory surgical center on the day of a surgical procedure

Clinical & Coding Specifications

Clinical Context

A 58-year-old male with coronary artery disease and chronic obstructive pulmonary disease presents for elective total knee arthroplasty under general anesthesia. On arrival to the preoperative holding area the anesthesia team documents that the patient admits to smoking a cigarette approximately two hours before surgery and has not abstained as instructed. The anesthesia record notes increased airway secretions and persistent cough. The anesthesiologist evaluates risk of perioperative bronchospasm and delayed emergence and documents the patient’s nonabstinence from tobacco on the day of surgery.

This event triggers documentation for intraoperative risk communication and potential billing with code G9645 to indicate the patient did not abstain from smoking prior to anesthesia. The clinical workflow includes preoperative nursing intake, anesthesia preoperative evaluation, anesthesia intraoperative record, and post-anesthesia recovery documentation. The anesthesia provider documents the smoking event, clinical observations (cough, secretions), any additional airway management or monitoring performed, and the rationale for any intraoperative modifications to care.

Coding Specifications

Modifier	Description	When to Use
`22`	Increased procedural services	Use when anesthesia care required substantially greater resources due to complications from preoperative smoking (rare for this code).
`23`	Unusual anesthesia	Use if emergency intraoperative anesthesia was required because of complications related to preoperative smoking that prevented planned technique.
`52`	Reduced services	Use if portions of planned anesthesia services were omitted due to patient nonabstinence or related events.
`53`	Discontinued procedure	Use when the surgical or anesthesia care was started but terminated because of acute issues from smoking before induction or during early anesthesia.
`54`	Surgical team primary service	Use when anesthesia team documents transfer of postoperative care to another surgeon/anesthesia team (team-based care after smoking-related complication).
`55`	Postoperative management only	Use when the billing provider only performs postoperative anesthesia management distinct from intraoperative care altered by smoking.
`56`	Preoperative management only	Use when preoperative anesthesia evaluation documents the smoking event and the anesthesia provider bills separate preop-only services.
`62`	Two surgeons	Use when another attending surgeon is required due to complications linked to the patient’s smoking status (rarely applied to anesthesia-centric billing).
`AS`	Physician assistant or other qualified nonphysician anesthetist service	Use when a qualified nonphysician anesthetist provides the anesthesia service influenced by smoking status.
`CO`	Carryover	Use for payor-specific carryover instructions when prior authorization or prior services interact with this claim (payor policy dependent).
`CQ`	Service furnished under arrangement	Use when anesthesia services altered by smoking are furnished under arrangement with another provider.
`FX`	Primary anesthetist when multiple anesthetists	Use to designate the primary anesthetist when multiple clinicians manage anesthesia due to complications from nonabstinence.
`FY`	Attending anesthetist absent	Use when the attending anesthetist was not present for portions of care due to emergent redeployment related to smoking complications.
`QK`	Medical direction of two, three, or four concurrent anesthesia procedures	Use when the physician directs multiple cases and documents medical direction despite increased complexity from smoking.
`QX`	CRNA service with CRNA not under medical direction by a physician	Use when a CRNA provides services impacted by the patient’s smoking without physician medical direction.
`QY`	Medical direction of one CRNA by a physician	Use when the physician medically directs a CRNA for a case complicated by preoperative smoking.

Taxonomy Code	Specialty	Notes
`207RA0000X`	Anesthesiology	Primary specialty that documents and bills anesthesia-related issues including `G9645`.
`2080P0201X`	Surgery - Orthopaedic Surgery	Common surgical specialty performing procedures where intraoperative anesthesia documentation of smoking may occur.
`207L00000X`	Pulmonary Disease	Consulted when increased bronchospasm or pulmonary complications are observed due to preoperative smoking.
`208000000X`	General Surgery	Frequently involved in operative cases where intraoperative smoking nonabstinence is documented.
`2084P0800X`	Critical Care Medicine	Engaged when perioperative respiratory decompensation occurs related to smoking.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
Data not available in the input.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`00100`	Anesthesia for procedures on integumentary system on head, neck, or posterior trunk; not otherwise specified	Represents typical anesthesia service codes that may accompany documentation of patient nonabstinence when such procedures are performed.
`00902`	Anesthesia for renal transplantation	Example of a major procedure where preoperative smoking may affect anesthetic management and trigger documentation with `G9645`.
`01400`	Anesthesia for procedures on lower abdomen; not otherwise specified	Common anesthesia code for abdominal procedures where preoperative smoking nonabstinence can increase pulmonary risk and require specific documentation.
`00530`	Anesthesia for extensive spine procedures	Major operative code where smoking status may impact intraoperative management and postoperative respiratory care.
`00840`	Anesthesia for intraperitoneal procedures in upper abdomen	Represents procedures often requiring general anesthesia and where `G9645` documentation may be reported if the patient smoked preoperatively.