Marloes Homberg

SUMMARY

Procedural sedation and analgesia (PSA) provided by anesthesia care providers is commonly applied in non–operating room settings. The primary objective of PSA is to ensure patient comfort by minimizing anxiety and pain during diagnostic or therapeutic interventions. Adequate patient tolerance—achieved through anxiolysis, amnesia, and/or analgesia—is essential for the safe and successful completion of such interventions.

The primary aim of this thesis was to evaluate the safety and quality of PSA administered by anesthesia care providers, with particular attention to complications and clinical outcomes in non–operating room anesthesia (NORA) settings. It seeks to identify opportunities to improve the quality of PSA and thereby optimize patient care. The studies included in this thesis focus on two common clinical indications: (1) catheter ablation for atrial fibrillation (AF) and (2) percutaneous thermal ablation of liver tumors. While deep sedation is applied in both procedures, the associated clinical challenges differ. During catheter ablation for AF, respiratory complications constitute the primary concern, whereas during percutaneous thermal liver tumor ablation, pain management represents the predominant challenge.

Chapter 1 introduces the background on various aspects of procedural sedation and analgesia. This chapter provides a concise description of procedural sedation and analgesia and the role of the anesthesia care provider, as well as the pharmacological agents used for sedation and analgesia and the associated side effects. The introductory Chapter concludes with the presentation of the research questions (RQs) that guide this thesis.

Chapter 2 reviews current evidence on the optimization of PSA during AF catheter ablation in non–operating room settings. The review demonstrates that no single optimal sedation strategy exists and emphasizes the need for individualized sedation based on patient characteristics, comorbidities, procedural complexity, required sedation depth, and provider experience. AF patients frequently present with comorbidities such as obesity and sleep-disordered breathing (SDB), which significantly increase the risk of respiratory complications and complicate the sedation management. Common screening tools for SDB show limited validity in this population, highlighting the need for improved pre-procedural risk stratification. Key determinants of clinical success include the selection of sedative and analgesic agents, appropriate sedation depth, and adequate monitoring strategies.

Chapter 3 studies the incidence and predictors of respiratory complications during PSA for AF catheter ablation through a retrospective cohort study including 232 patients. Respiratory complications occurred frequently (42.2%). Severe respiratory complications occurred in 15.1% of cases, including prolonged hypoxemic events and conversion to general anesthesia in 1.3% of patients. Several predictive factors for respiratory complications during PSA were identified. Key patient-related predictors included increased neck circumference, higher visceral fat percentage, self-reported tiredness, and the presence of comorbidities such as obstructive sleep apnea and chronic obstructive pulmonary disease. Due to the age distribution of the cohort (predominantly >50 years) the factor age showed limited discriminative value. A major procedure-related predictor was the duration of procedural sedation and analgesia, with longer sedation times associated with a higher risk of respiratory complications.

Chapters 4 and 5 examine the role of high-flow nasal oxygen (HFNO) during PSA for AF catheter ablation. The study protocol, described in Chapter 4, formed the methodological basis for the prospective, randomized controlled trial (RCT) reported in Chapter 5. The results of this RCT demonstrate that HFNO does not improve oxygenation compared with low-flow nasal oxygen (LFNO) in selected AF patients undergoing prolonged deep sedation, nor does it reduce the incidence of hypoxemia or sedation-related complications. Although HFNO was shown to be safe, it provided no additional clinical benefit in this setting. Given the associated costs and environmental impact, routine use of HFNO during PSA for AF ablation cannot be justified. These findings support a more selective and context-specific application of HFNO in cardiology-related PSA.

Chapter 6 investigates, based on a retrospective cohort study, the prevalence, severity, and predictors of acute post-procedural pain following percutaneous thermal liver tumor ablation with PSA. Acute pain in the recovery room occurred frequently, with a prevalence of 42.7% when defined as a Numeric Rating Scale (NRS) score ≥4 and a mean maximum NRS of 3.1 ± 2.8. Psychological factors—including depression, anxiety, and the use of psychopharmacological medication—were the strongest predictors of higher pain scores. In addition, female sex, younger age, and a history of chronic pain were associated with increased post-procedural pain, whereas tumor-related characteristics such as size, location, and number of lesions showed no association with pain severity. These findings underscore the importance of patient-specific psychological and physiological factors in pain perception and support a shift toward individualized, multimodal peri-procedural analgesic strategies. Early identification of patients at risk, combined with tailored pharmacological and non-pharmacological interventions, may improve pain control, recovery, and overall patient experience following percutaneous liver tumor ablation.

Chapter 7 provides an overview and a general discussion of the results of the studies included in this thesis. A dedicated section of the general discussion focuses on minimally invasive procedures and NORA, including PSA, in the context of the two clinical indications (1) catheter ablation for atrial fibrillation (AF) and (2) percutaneous thermal ablation of liver tumors. Methodological considerations are addressed, and directions for future research are proposed. Future research should focus on identifying patient- and procedure-related risk factors for complications and on optimizing patient comfort through individualized pharmacological and non-pharmacological strategies. Multidisciplinary collaboration between experts from different departments and specialties will be essential to translate these insights into clinical practice.