Carbon dioxide vs. air insufflation in ileo-colonoscopy and in gastroscopy plus ileo-colonoscopy: a comparative study

Insuflación de CO₂ vs. aire en íleo-colonoscopia y en gastroscopia más íleo-colonoscopia: estudio comparativo

María Fernández-Calderón¹, Miguel Ángel Muñoz-Navas¹, Juan Carrascosa-Gil², María Teresa Betés-Ibañez¹, Susana de-la-Riva¹, César Prieto-de-Frías¹, María Teresa Herráiz-Bayod¹ and Cristina Carretero-Ribón¹

Department of Gastroenterology. ¹Clínica Universidad de Navarra. Navarra. Spain. ²Hospital de Zumárraga. Guipúzcoa. Spain.

Correspondence

ABSTRACT

Introduction: insufflation with carbon dioxide (CO₂) during endoscopies compared to air is associated with a decrease in abdominal discomfort after the examination, because CO₂ is readily absorbed through the small intestine and eliminated by the lungs.
Aims: the objective of this randomized clinical trial was to assess the effect of CO₂ insufflation on pain and abdominal distension after an ileo-colonoscopy (I) and after an ileo-colonoscopy plus gastroscopy (I+G).
Material and methods: we included a total of 309 patients in the study and all endoscopies were performed under sedation with propofol. Two hundred fourteen patients underwent an I (132 with CO₂ / 82 with air) and 95 underwent an I+G (53 with CO₂ / 42 with air). Abdominal pain was studied at 10, 30 and 120 minutes of exploration and abdominal perimeter difference before and after the procedure.
Results: both in group I and in group I+G, the use of CO₂ translated into an average of abdominal pain significantly lower (p < 0.05). Similarly, a smaller increase in waist circumference was found among group I and group I+G, in patients where CO₂ was used (p < 0.05).
Conclusion: the insufflation of CO₂ instead of air during the performance of endoscopy significantly reduces the discomfort and abdominal pain after an ileo-colonoscopy and after a gastroscopy + ileo-colonoscopy.

Key words: CO₂ insufflation. Endoscopy. Ileo-colonoscopy.

RESUMEN

Introducción: la insuflación con dióxido de carbono (CO₂) durante las endoscopias digestivas comparado con el aire, se asocia a una disminución de las molestias abdominales después de la exploración, ya que el CO₂ es fácilmente absorbido por el intestino delgado y eliminado por los pulmones. ]]> Objetivo: el objetivo de este ensayo clínico aleatorizado fue valorar el efecto de la insuflación de CO₂ sobre el dolor y la distensión abdominal después de una ileo-colonoscopia (I) y después de una íleo-colonoscopia + gastroscopia (I+G).
Material y métodos: se incluyeron un total de 309 pacientes en el estudio y todas las endoscopias fueron realizadas bajo sedación con propofol. A 214 pacientes se les realizó una I (132 con CO₂ / 82 con aire) y a 95 se les realizó una I+G (53 con CO₂ / 42 con aire). Se estudió el dolor abdominal a los 10, 30 y 120 min de la exploración y la diferencia de perímetro abdominal antes y después del procedimiento.
Resultados: tanto en el grupo I como en el grupo I+G, se objetivó una media de dolor abdominal en los pacientes en los que se utilizó CO₂ significativamente menor que en los que se utilizó aire (p < 0,05). Y de igual modo se objetivó un menor incremento en el perímetro abdominal para el grupo I y para el I+G en los pacientes en que se utilizó CO₂ frente a los que se utilizó aire (p < 0,05).
Conclusión: la insuflación de CO₂ en vez de aire durante la realización de la exploración endoscópica, reduce significativamente el disconfort y el dolor abdominal después de una ileo-colonoscopia y después de una íleo-colonoscopia + gastroscopia.

Palabras clave: Insuflación CO₂. Endoscopia. Íleo-colonoscopia.

Introduction

In order to achieve an adequate visualization of the gastrointestinal mucosa during gastrointestinal endoscopy it is necessary to use gas insufflation. An average of 8 L of gas (air or CO₂) has been estimated to be required during colonoscopy (1). Many patients manifest discomfort in the gastrointestinal tract associated with air insufflation. In the last years different methods have been evaluated to improve patient tolerance to endoscopy and most of these complaints have been solved with the widespread use of sedation. Other methods as CO₂ insufflation have optimized tolerance.

Other authors have seen that the use of carbon dioxide (CO₂) during colonoscopy compared with room air, is associated with a decrease in pain after the procedure (2-7), because CO₂ has the peculiarity that it is rapidly absorbed from the gastrointestinal tract and is eliminated through the respiratory tract (this does not occur with air, which can only be removed through a natural way), achieving a rapid decompression of the gastrointestinal tract. This feature would allow the reduction of pain during and after the examination, and also of the need for sedation or anesthesia and of the exploration and recovery times (8).

Since Rogers did a small study evaluating the safety of CO₂ insufflation during endoscopy in 1974 (9), a number of authors have evaluated its use in gastrointestinal endoscopy: sigmoidoscopy (10), colonoscopy (1-7), ERCP (11,12) and recently double-balloon enteroscopy (13,14) and endoscopic submucosal dissection (15,16).

Material and methods

A team of six doctor-nurse groups participated in the study (four of medical endoscopists with more than 10 years of experience). We included a total of 309 patients who were undergoing a colonoscopy or gastroscopy plus colonoscopy. All patients signed, before the randomization, a specific informed consent for the study, which was approved by the hospital ethics committee. Exclusion criteria were: patients with a history of: abdominal surgery, inflammatory bowel disease, irritable bowel syndrome, severe chronic obstructive pulmonary disease or age over 80 or under 18 years old.

Of 309 patients, 214 (69.3%) underwent an I (132 were randomized to CO₂ insufflation and 82 to air) and 95 (30.7%) underwent an I+G (53 CO₂/ 42 air). All procedures were performed under sedation with propofol, administrated by bolus or by infusion pump controlled by the anesthetist. We used a CO₂ insufflator Olympus UCR (Endoscopic CO₂ Regulation Unit).

The study was done by filling a questionnaire which contained 20 variables: age, gender, body mass index, weight, height, type of endoscope used, abdominal circumference before and after the examination, doctor-nurse team, type of bowel preparation, cleaning of the colon, duration of exploration, polypectomy, presence or absence of diverticula, the necessity or not to modify the stiffness of the endoscope, the need or not of manual pressure required for advancing the scope, propofol dose given, the need to pullback the scope or mobilize the patient for the procedure and tolerance to the test as abdominal pain.

Once the baseline characteristics of the patients were homogeneous, we specifically studied the following variables: abdominal pain, measured by visual analog scale (1 no-pain/10 worst pain) after 10 minutes, at discharge from the endoscopy unit (approximately 30 minutes) and 2 hours after by telephone contact; and second, the abdominal circumference difference before and immediately after the procedure, always measured at periumbilical level by the same nurse, who did not know which type of gas was used.

Statistical analysis

We used a parametric test (Student t test) for statistical analysis because the variables followed a normal distribution and we used the statistical program SPSS 13.0. Differences were considered significant between groups when p was less than 0.05.

The 4 groups were similar in age, gender, weight, height, BMI and dose of propofol (Tabla I). There were no differences in the type of bowel preparation, cleansing, duration of exploration, performing polypectomies, presence of diverticula or need to perform various maneuvers to advance the endoscope.

Considering patients who underwent an ileo-colonoscopy, at 10 minutes the score on the visual analog scale was an average of 1.29 in the CO₂ group vs. 2.16 in the room air group; at 30 minutes, an average of 1.05 vs. 1.39 respectively; and at 120 minutes, an average of 1.01 vs. 1.13 respectively. All differences were statistically significant. It also showed that, although the differences were greater at the end of endoscopy (at 10 minutes), at 2 h they remained statistically significant (p = 0.003) (Fig. 1).

In the other group (I+G group), the tolerance after 10 minutes was an average of 1.08 in the CO₂ group vs. 2.36 in the room air group; after 30 minutes, an average of 1.02 vs. 1.55 respectively; and after 120 minutes, an average of 1 vs. 1.07 respectively. All differences were statistically significant (p < 0.05) (Fig. 2).

In terms of increasing abdominal perimeter, in the I group, at the end of the endoscopy, we observed an average of 1.11 cm in the CO₂ group vs. 1.58 cm in the room air group (p < 0.05) (Fig. 3). In the I+G group at the end of the endoscopy, we observed an average increase in abdominal circumference of 0.81 cm in the CO₂ group vs. 2.07 cm in the room air group (p < 0.05) (Fig. 4). Also, the difference found in the increase of the abdominal perimeter comparing CO₂ and air in the group I + G is greater than in the ileo-colonoscopy group (Figs. 3 and 4).

No complications occurred during the study.

Discussion

Several studies have shown that CO₂ insufflation instead of air during endoscopy can reduce discomfort after the procedure.

Many of the studies published have evaluated the degree of abdominal pain measured by visual analog scale (VAS), at different moments after the colonoscopy. For example, Stevenson et al. (2) published the results of a small study (n = 56), which assessed the effect of CO₂ insufflation vs. air in abdominal pain after a colonoscopy. A statistically significant difference (p < 0.0005) was observed 6 h after and the day after the procedure (p = 0.01) in the group that used CO₂ vs. the air group. Later, Bretthauer et al. (3) showed that CO₂ insufflation significantly reduced abdominal pain at the time, 3 h, 6 h and 24 h after a colonoscopy.

Some authors have postulated that CO₂ insufflation may reduce the need for sedation or anesthesia, but few studies have specifically analyzed the effect on sedation. In 2003, Church et al. (5) published the results of a test assessing the degree of abdominal pain immediately after colonoscopy in patients who had used CO₂ vs. air, showing less abdominal pain 10 minutes after the colonoscopy in the CO₂ group (p < 0.05) but no differences were related to sedation.

The study of Riss et al. (17) evaluated the efficacy of CO₂ insufflation after colonoscopy in patients with varying degrees of sedation and, in parallel, the degree of acceptance of screening programs for colorectal cancer (CCR). This study randomized 300 patients to undergo the procedure with CO₂ or air, showing less abdominal pain in the CO₂ group (p < 0.01) 15, 30 minutes and 6 h after the procedure. But carrying out the analysis according to the level of sedation of patients, we found no differences in the degree of personal satisfaction after the test, or the acceptance of CCR screening programs.

Moreover, given that CO₂ insufflation might theoretically involve retention of carbon dioxide and that this retention is favored by sedation (as it may cause hypoxemia and hypoventilation), Bretthauer et al. (6) randomized 103 patients to CO₂ or air insufflation in colonoscopy, collecting tidal CO₂ levels (CO₂ ET: End-tidal Carbon Dioxide) before, during and 10 minutes after the procedure. All patients received sedation with Pethidine and Midazolam. Lower degree of abdominal discomfort was observed in the CO₂ group compared to the air group, but no statistically significant differences were found in ET CO₂ in relation to sedation.

The rate of cecal intubation is an indicator of quality in colonoscopy. Studies have analyzed the colonoscopy exploration mean time using CO₂. A double-blind randomized clinical trial published by Yamano et al., in 2010 (7), evaluated the effect of CO₂ insufflation in colonoscopy without sedation on the partial pressure of CO₂ in the blood (pCO₂), on the volume of gas pumped, on the abdominal pain, and on the exploration time. They found lower pCO₂ levels compared with the reference range and reduced exploration time. They concluded that CO₂ insufflation reduces the examination time and enhances the rate of cecal intubation in colonoscopies without sedation. This suggests that the effects of CO₂ are more evident in longer explorations.

Another interesting aim in the evaluation of the use of CO₂ in endoscopy has to do with the degree of experience of the endoscopist. Some authors argue that cecal intubation rate is higher in more experienced endoscopists (18) and this helps to get better results. In our work it was not necessary to analyze the rate of cecal intubation because it was achieved in all patients included in the study, and ileo-colonoscopy was performed in addition. A Japanese group conducted in 2009 a study that evaluated the efficacy of CO₂ insufflation in potentially difficult colonoscopies in relation to the level of experience of the endoscopist (18). Overall there was a beneficial effect of CO₂ vs. air on abdominal pain (p < 0.001) and subgroup analysis showed significantly lower pain score in the group of experienced endoscopist (p = 0.023).

Our study is the first to analyze the effect of CO₂ on abdominal pain and distention after an I and after an I+G. It seemed interesting to assess the effects of CO₂ insufflation compared to air for an exploration in which, after a complete colonoscopy, we explored the small bowel and therefore insufflated gas at this level.

Conclusion

CO₂ insufflation in endoscopic procedures can improve patient tolerance in relation to less abdominal pain and a significantly lower abdominal diameter. The use of CO₂ could be indicated in general and especially in long explorations and/or complicated ones, such as performing an ileo-colonoscopy and an ileo-colonoscopy + gastroscopy.

By improving patient tolerance to colonoscopy, we think that CO₂ insufflation may improve population adherence to screening programs.

References

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Correspondence:
María Fernández Calderón
Department of Gastroenterology.
Clínica Universidad de Navarra
Av. Pío XII 36. ]]> 31008, Pamplona, Navarra. Spain
E-mail: mfdezcalderon@gmail.com

Received: 10-11-11
Accepted: 13-12-11