Preoperative Frailty and Suboptimal Mask Ventilation in Cardiac Surgery Patients

This single-center, prospective observational study will consecutively enroll eligible patients aged 60 years and older with American Society of Anesthesiologists (ASA) physical status II-IV who are scheduled for elective coronary artery bypass grafting, valve surgery, or combined cardiac surgery under general anesthesia at Ankara Bilkent City Hospital. Written informed consent will be obtained before participation. The study will not alter routine anesthesia or surgical care. Demographic and clinical characteristics, body mass index, comorbidities, left ventricular ejection fraction, and planned surgical procedure will be recorded. Airway assessment will include Mallampati class, thyromental distance, neck circumference, and the neck circumference-to-thyromental distance ratio. Preoperative frailty will be assessed using the 9-point Clinical Frailty Scale (CFS), ranging from 1 (Very Fit) to 9 (Terminally Ill). Higher scores generally indicate greater frailty; a score of 9 denotes terminal illness. Assessment will be based on clinical evaluation and patient interview. For the primary analysis, patients with CFS scores ≥4 will be classified as belonging to the vulnerable/frail spectrum, and patients with scores <4 will form the comparison category. Handgrip strength will be measured preoperatively using a calibrated hand dynamometer. Measurements will be obtained from the dominant hand with the patient seated, the shoulder adducted and in neutral rotation, and the elbow flexed at 90 degrees. Three measurements will be obtained, and their mean value, expressed in kilograms, will be used in the analyses. Low muscle strength will be defined according to the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) criteria as handgrip strength <27 kg in men and <16 kg in women. Handgrip strength will be evaluated both as a continuous variable and as a categorical variable according to these sex-specific thresholds. Its association with suboptimal mask ventilation and its additional predictive value beyond frailty assessment will be investigated. Following preoxygenation, intravenous anesthesia induction and neuromuscular blockade will be performed as part of routine clinical care. Patients will be positioned supine. Mask ventilation will initially be performed using a one-handed mask-holding technique, with the other hand used to manually compress the reservoir bag. Initial peak inspiratory pressure will be limited to 20 cmH₂O. Ventilation adequacy will be assessed during the first 20 breaths after anesthesia induction. Exhaled tidal volume, end-tidal carbon dioxide waveform, peak inspiratory pressure, and peripheral oxygen saturation will be recorded. If ventilation is inadequate, standard airway optimization measures will be undertaken, including oropharyngeal airway placement, adjustment of inspiratory pressure, and two-person ventilation, as clinically required. Use of an oropharyngeal or nasopharyngeal airway and the requirement for two-person ventilation will be documented. Mask ventilation will be performed by an anesthesia resident with at least four years of experience. Suboptimal mask ventilation (SMV) will be defined as the presence of at least one of the following criteria during assessment of the first 20 breaths: exhaled tidal volume <5 mL/kg of ideal body weight; an absent or inadequate end-tidal carbon dioxide waveform; requirement for two-person mask ventilation; requirement for an oropharyngeal or nasopharyngeal airway; or peripheral oxygen saturation <92%. SMV will be recorded as a binary outcome, indicating whether one or more of these criteria are present. During subsequent tracheal intubation, the laryngoscopic view will be graded using the Cormack-Lehane classification. The number of intubation attempts and first-attempt intubation success will also be recorded. Preoperative frailty and handgrip strength assessments and intraoperative mask ventilation assessments will be performed by different investigators. The investigator assessing intraoperative mask ventilation will be blinded to the preoperative CFS and handgrip strength results. The primary outcome is the occurrence of SMV. The primary objective is to evaluate the association between preoperative frailty and SMV. Secondary outcomes include the lowest peripheral oxygen saturation, ventilation parameters, airway adjunct use, requirement for two-person ventilation, Cormack-Lehane grade, number of intubation attempts, and first-attempt intubation success. Secondary objectives are to evaluate the association between handgrip strength and SMV, determine whether handgrip strength provides additional predictive information beyond frailty assessment, and investigate the relationship between SMV and intubation difficulty. Multivariable logistic regression and receiver operating characteristic curve analyses are planned. A total of 450 participants will be enrolled, allowing for approximately 10% data loss. Recruitment and prospective data collection are expected to take approximately one year.