This study evaluates two brief, non-drug psychological techniques-body-scan mindfulness and guided imagery/distraction-delivered as a single bedside session to reduce acute pain in adults admitted to short-stay inpatient wards or emergency observation units in Boyacá, Colombia. Participants are randomly assigned (1:1:1) to body-scan mindfulness, guided imagery/distraction, or a brief cognitive-behavioral psychoeducation session (active comparator). Each session lasts under 20 minutes and usual medical care continues. Pain intensity (0-10) is recorded within 5 minutes before the session and within 2 minutes after completion on the same day. If pain remains very high (e.g., ≥8-9/10) or the activity cannot be completed, up to 5 minutes of supervised slow deep-breathing may be offered as rescue, and the clinical team may adjust analgesics per routine care. Secondary measures (specified in Outcome Measures) include patient satisfaction, feasibility (session duration and completion), use of rescue measure, and adverse events; exploratory data may include short-term psychological scales collected by a blinded assessor and the association with length of stay during the current admission. Adults aged ≥18 years with acute pain ≤7 days and baseline pain ≥4/10 may be eligible. The study takes place across four public hospitals in Boyacá, Colombia.

This is a parallel-group, open-label, three-arm randomized trial (1:1:1) in short-stay inpatient wards and emergency observation units at four public hospitals in Boyacá, Colombia. The objective is to estimate the immediate effect of a single, brief bedside behavioral session on acute pain while routine medical care continues unchanged. Clinically stable adults provide written informed consent prior to any study procedures.

Participants are randomized to one of three groups. Group A (body-scan mindfulness) receives a guided practice that cultivates open, non-judgmental attention across body regions, including areas without pain, to modulate the nociceptive experience. Group B (guided imagery/distraction) receives a session using neutral/pleasant imagery and simple attentional shifts intended to redirect focus away from painful sensations. Group C (CBT-based psychoeducation; ABC model) serves as an active comparator and consists of a brief, structured explanation of the relationship between thoughts, emotions, and sensations using a practical example; no skills training is included. Each technique is delivered once (<20 minutes) by trained study personnel (e.g., psychology staff). The attending clinical team (physicians/nurses) is informed of participation and may adjust routine care as needed, but does not deliver study techniques or collect study outcomes. If post-session pain remains very high or a participant cannot complete the assigned activity, up to 5 minutes of supervised slow deep-breathing may be offered as a rescue measure; any analgesic adjustments are per routine care and are not protocol-driven.

Randomization uses a computer-generated sequence with variable permuted block sizes (1:1:1) prepared in advance and stored in a password-protected spreadsheet with locked sheets/cells and restricted access. Assignment is centralized: after eligibility confirmation, informed consent, and documentation of baseline pain, the enrolling clinician contacts the study coordinators, who control the file and release the next sequential assignment. Block sizes and the remaining sequence are concealed from enrolling staff; each release is time-stamped and logged to preserve allocation concealment and balanced assignment across arms.

Assessments follow standardized procedures. The primary endpoint is the immediate pre- to post-session change in pain intensity; operational details (instruments and exact time windows) are specified in Outcome Measures and captured on case-report forms. Where feasible, a blinded outcomes assessor administers only the post-session psychological scales 5-10 minutes after the session (e.g., PSEQ-10, PCS, HADS-A) and has no access to pain ratings or allocation files. Pain ratings and the participant satisfaction questionnaire are recorded at bedside by study personnel involved in the session. The pre-session length of stay during the index admission may also be abstracted from the medical record as specified in Outcome Measures.

The analysis overview is prespecified. The primary comparison of immediate pain change across arms will use a linear model under intention-to-treat, with post-session pain as the dependent variable and baseline pain and study site as covariates; adjusted mean differences with 95% confidence intervals will be reported. Secondary endpoints (e.g., safety and patient-reported satisfaction) will be summarized with models appropriate to their scale. Exploratory analyses will compare post-session psychological scale scores across arms and examine the association between pre-session length of stay and pain change. Missing post-session pain data are expected to be minimal; if present, prespecified sensitivity analyses (e.g., complete-case vs simple imputation) will be conducted. No multiplicity adjustment is planned for secondary/exploratory outcomes. Ethics approvals were obtained from the participating institutions; written informed consent is required prior to any study procedures.

Inclusion Criteria:

• Age ≥18 years.
• Admitted to short-stay inpatient or emergency observation units at participating hospitals (same index admission).
• Acute pain ≤7 days with baseline pain ≥4/10 on a 0-10 numeric/visual scale.
• Clinically stable and able to remain at bedside for ~30-40 minutes (consent, baseline, single session, post-session assessment).
• Analgesic regimen stable ≥1 hour before baseline pain rating (no planned change during the ~20-minute study window unless clinically required).
• Able to understand simple instructions and communicate pain ratings (verbal or pointing) and to provide written informed consent.

Exclusion Criteria:

• Cancer-related pain or chronic pain >6 months (e.g., widespread musculoskeletal pain/fibromyalgia).
• Active inflammatory/degenerative rheumatic disease causing ongoing daily pain that would confound acute pain ratings (e.g., rheumatoid arthritis flare, advanced osteoarthritis, severe osteoporosis-related pain).
• Cognitive impairment/dementia, delirium, or acute severe psychiatric disturbance that prevents consent or reliable self-report.
• Respiratory conditions that contraindicate slow deep-breathing rescue (e.g., decompensated COPD, acute asthma, need for high-flow oxygen or ventilatory support).
• Hemodynamic or clinical instability (e.g., need for urgent procedure; in resuscitation/reanimation area; RASS ≤ -3; MAP <65 mmHg or SBP <90 mmHg; SpO₂ <90% despite usual oxygen) at screening.
• Participation in another interventional study targeting pain during the same admission.
• Refusal to participate or withdrawal of consent.

De-identified individual participant data (IPD) underlying the primary outcome will be shared. Direct identifiers will be removed and indirect identifiers minimized in accordance with Colombian data protection law and IRB approvals.

Within 12 months after publication of the primary results; available for 24 months thereafter.

Available upon reasonable request to the corresponding author/UPTC data custodian for qualified researchers with a methodologically sound proposal and ethics approval, after signing a Data Use Agreement.

Single-blind (outcomes assessor). An external evaluator, not present during the intervention and unaware of group assignment (arms labeled A/B/C), administers and scores prespecified secondary outcomes-Pain Self-Efficacy Questionnaire (PSEQ-10), Pain Catastrophizing Scale (PCS), and Hospital Anxiety (HADS-A)-and has no access to baseline scores at the time of assessment. Participants and interventionists are not blinded. The primary outcome (acute pain 0-10) is patient-reported at bedside. Allocation is concealed until assignment (computer-generated variable blocks). Any inadvertent unblinding is documented.