A screening colonoscopy is a validated tool for early diagnosis of colorectal cancer. This is an important reason why colonoscopy belongs to the most common endoscopic gastrointestinal examinations. However, motivating patients to participate in colonoscopy screening continues to be a challenge. The lack of knowledge about the procedure may be a significant barrier preventing patients from undergoing screening. Patients complain about disruption of normal daily activities by bowel preparation for colonoscopy, prolonged analgosedation after colonoscopy, as well as the need to be accompanied when returning home. There is an ongoing discussion on sedation-free colonoscopy, and there is no consensus in this regard. While in some countries it is a common practice to perform colonoscopy without sedation, this type of management is considered unfeasible and is not recommended in other countries. In countries where colonoscopy is performed under analgesia, a trend towards deeper levels of sedation may be observed (1). Sedation in colonoscopy increases the costs of examination. Also, the costs associated with absenteeism, additional personnel, the use of equipment for analgosedation and general anaesthesia as well as monitoring and surveillance of patients after colonoscopy under analgosedation should be considered. Additionally, patients complain about the need to be accompanied when returning home, about limited physical activity as well as the risk of anaesthesia-related complications. Analgosedation in colonoscopy should be considered for at least two reasons: 1) the patient may be anxious and afraid of violation of their physical intimacy, 2) due to colonoscopy-related pain. Each of these reasons requires the use of two different agents, with benzodiazepines being an appropriate choice for patients with fear and anxiety associated with intimacy, and opioids recommended for pain. Deep sedation using propofol or even general anaesthesia is another method used in some countries. Colonoscopy may be well-tolerated by some patients, with high levels of satisfaction and only minor or no pain, whereas in other cases the procedure may require deep sedation. The underlying causes are multifactorial and include such elements as previous abdominal surgeries and the resulting adhesions, individual anatomy of each patient, the skillfulness of an endoscopist, patient expectations, local traditions, endoscopic insertion technique and the type of endoscopic equipment.

Pain during colonoscopy is considered to be visceral, resulting from the activation of sensory afferent nerves that innervate the intestines. The main triggering factors include stretching of the sigmoid wall and mesenteric attachments due to excessive intestinal distension and colonoscope looping (2). Visceral pain often triggers autonomous reflexes, such as perspiration, bradycardia, vertigo, hypotension and nausea. Although pain is a physiological response to tissue damage, it also includes emotional and behavioural responses depending on the individual experiences and cultural background, which are often resistant to analgesic treatment. Young women with low body mass index (BMI) show lower pain tolerance as opposed to older patients. It is difficult to predict pain intensity in each patient.

Analgosedation for colonoscopy is currently a widely discussed issue. Sedation in colonoscopy is a standard management in the USA, with different studies recommending either moderate or deep sedation. Other parts of the world argue for medication-free colonoscopy (3). Eckardt et al. showed in their study including 2,500 patients that analgosedation-free colonoscopy was possible in 95% of patients if performed by an experienced endoscopist using optimal equipment. However, no reports on patient satisfaction with the performed endoscopic procedure were presented (4). Nowadays, the use of colonoscopes employing the water method, and experienced endoscopists make colonoscopy without sedation possible for a motivated group of patients (5-7). Success rates depend on appropriate patient selection. Male gender, higher levels of education, low preprocedural anxiety, and patient’s preference for procedures without sedation are predictors of a successful sedation-free procedure. However, unpredictable individual anatomical differences can lead to unacceptable discomfort for the patient and poor procedural conditions for analgosedation-free colonoscopy.

Levels of sedation, ranging from moderate to deep, are defined in sedation guidelines. Deep sedation is usually achieved using intravenous propofol, which has a rapid onset and short duration of action, allowing for a reduced recovery time. Therefore, there is an increasing interest in propofol-based sedation among gastroenterologists. It should be noted, however, that propofol has a relatively narrow therapeutic range, which increases the risk of sedation-related adverse effects. Most states in the United States do not allow the use of propofol by non-anaesthesiologists. In Poland, this anaesthetic is also used only by anaesthesiologists (8-12). The European guidelines allow for the administration of propofol by trained nurses or endoscopists who do not perform colonoscopy at the same time (13). However, this permission only concerns moderate, and not deep sedation. Deep sedation requires specialist equipment and training, and it may be performed only by trained personnel and under appropriate monitoring (14). The rates of colonoscopies performed by specialised anaesthetic teams increased from 23.9% in 2007 to 53.4% in 2015, respectively, and are still rising (15). Deep sedation may cause spontaneous ventilation failure, which may require assistance to maintain patent airways. An analysis of aesthetic-related adverse events registry demonstrated that serious adverse events can occur during deep sedation, even when performed by properly trained personnel (16). The most common adverse effects include respiratory depression, cardiovascular events, delayed recovery of consciousness, and prolonged time between analgosedation and hospital discharge. Deeply sedated patients are not able to change their body position during examination, which makes it difficult to maneuver the patient. Moderate sedation is defined as a drug-induced depression of consciousness. Moderately sedated patients are able to purposefully respond to verbal commands. Spontaneous ventilation is adequate, and there is no the risk of airway obstruction. Agents that are most commonly used for moderate sedation include midazolam and other benzodiazepines or midazolam combined with an opioid. Although combination of a sedative and an opioid is excellent for colonoscopy, it increases the risk of unintentional deep sedation and more common respiratory depression. The duration of analgosedatives may be longer than the duration of the procedure, resulting in prolonged recovery with a delay in hospital discharge, increased costs, and disruption of daily activities of the patients.