Regional Versus General Anesthesia for Hip Fracture and Postoperative Oxygenation (REGENERATION)

With this study, the investigators intend to measure oxygen saturation before and after hip surgery in the context of proximal femur fracture, comparing two types of anesthesia (general or spinal). The investigators also intend to study the effects of the two anesthetic techniques on sleep apnea, delirium, respiratory complications, and length of hospital stay.

This is an observational study, in which oxygen is measured at the fingertip with a sensor and a bracelet, without any intervention, inconvenience, or discomfort for the participant. Data will be collected on: respiratory complications, sleep apnea, delirium, length of hospital stay, and survival.

Data will be collected in the operating room and wards of Santa Maria Hospital, Lisbon, Portugal over a period of approximately 24 hours after the participant's operation. Information about participant's health and co-morbidities will be recorded.

There will be no implication for the participants' clinical care, since the study measurements will not be sent to the health professionals in charge. The operation, recovery, and treatments will not be influenced at any time by participation in the study.

Study Overview

• Status: Recruiting
• Conditions: General Anaesthesia; Regional Anaesthesia; Hip-fracture

Detailed Description

Frailty, comorbidities, medication (anticoagulants and anti-platellet agents) as well as acute and chronic illnesses have an impact on the choice of anesthesia strategy for hip fracture surgery. The choice between general anesthesia (GA) and loco-regional, spinal anesthesia (SA) may have impact on the postoperative period. Despite previous retrospective studies on this topic, it remains uncertain that either is superior in terms of post-operative outcomes, including mortality, delirium and respiratory complications, with conflicting results in the literature.

Postoperative pulmonary complications (PPC) are amongst the commonest complications in geriatric hip fractures, reported to be around 12%. The elder population at Hospital de Santa Maria (Tertiary University Hospital Center) receives the most challenging cases, with pilot data from the past 3 years (2022-2024, n=927) revealing an average risk score for PPC of 32,1%.

Considering that low oxygen saturation is an independent risk factor and a strong predictor for PPC, the investigators seek to compare the oxygenation during the perioperative period between the different anesthesia regimens.

The study hypothesis is that the anesthesia regimen (GA vs SA) has an impact on the oxygenation index during the first 24 postoperative hours.

The secondary objectives are to compare the sleep apnea index between GA and SA, the incidence of PPC, delirium, mortality and the length of stay (LOS) in the PACU and until discharge from the hospital.

• Study Type: Observational
• Enrollment (Estimated): 102

Contacts and Locations

Study Locations

• Portugal
  • Lisbon District
    • Lisbon, Lisbon District, Portugal, 1635
      • Recruiting
      • Northern Lisbon Hospital Center
      • Contact: Andre dos Santos Rocha, MD, PhD; Phone Number: +351 969 345 052; Email: andrerocha@medicina.ulisboa.pt

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Probability Sample

Study Population

Elder subjects with hip-fracture submitted to surgery.

Description

Inclusion Criteria:

• hospital admission for hip fracture;
• scheduled for hip fracture surgery;
• age above 65 years, both genders;
• capable of consent or consent by responsible person;

Exclusion Criteria:

• hip fracture during hospitalization (not present upon admission)
• patient refusal to participate

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
General anaesthesia; Hip fracture surgery under general anaesthesia
Rregional anaesthesia; Hip fracture surgery under regional anaesthesia

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Oxygenation index (SpO2/FiO2 ratio)	Oxygenation index (SpO2/FiO2 ratio) measured as the difference between oxygenation index on admission to the operating room and the mean SpO2 during the next 24 postoperative hours, compared between groups. Peripheral oxygen saturation measured continuously during the first postoperative day with the Konica Minolta PULSOX-DS5® device.	first postoperative day

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sleep Apnea index	average dips of SpO2 per hour, (>= 4%)	first postoperative day
Length of stay in the Post-anestesia Care Unit	Length of stay in the Post-anestesia Care Unit	after the surgery, at discharge from the Post-anestesia Care Unit
Hospital Length of Stay (Days)	Length of stay in the hospital from admission until discharge, in days	from hospital admission to hospital discharge, approximatelly 5 days
postoperative pulmonary complications	postoperative pulmonary complications defined as hypoxemia, respiratory failure, atelectasis, pneumothorax, respiratory infection.	during the first postoperative day
Delirium	Presence of delirium in the first postoperative day	during the first postoperative day
in-Hospital mortality	death from any cause during hospital stay, from hospital admission to discharge	From hospital admission to hospital discharge (or death), up to 3 months

Collaborators and Investigators

• Sponsor: University of Lisbon
• Collaborators: Northern Lisbon Hospital Center

Study record dates

Study Major Dates

• Study Start (Actual): November 27, 2025
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: November 27, 2025
• First Submitted That Met QC Criteria: December 19, 2025
• First Posted (Actual): December 30, 2025

Study Record Updates

• Last Update Posted (Actual): December 30, 2025
• Last Update Submitted That Met QC Criteria: December 19, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: anaesthesia; oxygenation; sleep apnea; postoperative pulmonary complications; hip femur fracture
• Additional Relevant MeSH Terms: Nervous System Diseases; Wounds and Injuries; Respiratory Tract Diseases; Leg Injuries; Respiration Disorders; Sleep Wake Disorders; Fractures, Bone; Apnea; Sleep Disorders, Intrinsic; Dyssomnias; Femoral Fractures; Hip Injuries; Sleep Apnea Syndromes; Hip Fractures
• Other Study ID Numbers: CE-CAML 221/25

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: only anonymised data can be shared after publication and upon reasonable request

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No