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Effects of anesthesia on esophageal sphincters in obese patients
Örebro University, School of Health and Medical Sciences.
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The lower esophageal sphincter (LES) and the upper esophageal sphincter (UES) play a central role in preventing regurgitation and aspiration. The aim of this thesis was to evaluate the UES, LES, esophageal (E) and barrier (Br) pressures (P) using high resolution solid state manometry (HRSM). Comparisons were made between obese and nonobese patients, before and during anesthesia induction, and in obese patients in different body positions and during different respiratory maneuvers.

Methods: The effects of low-dose propofol (0.3 mg/kg iv) were studied in 10 young (ages 18–30 years) and 10 elderly volunteers (ages 60–87 years). The effects of anesthesia induction with remifentanil, propofol and rocuronium were studied in 14 obese patients (BMI >35 kg/m2) and compared with effects in 14 non-obese patients. The effects of different body positions on esophageal sphincters were evaluated in 17 obese patients before and during anesthesia. The effects of different respiratory maneuvers on pressures in the esophagus and esophageal sphincters were studied before and during anesthesia in 17 obese patients. HRSM was used in all studies.

Results: The low propofol dose did not infl uence LES pressures in either young or elderly volunteers. Anesthesia induction with Remifentanil and Propofol decreased pressures in the esophageal sphincters and the BrP in both obese and non-obese patients. The pressures were signifi cantly lower in obese patients. The BrP remained positive in both obese and non-obese individuals. The LES pressure increased in the Trendelenburg position before but not during anesthesia. During spontaneous breathing the LES pressure was signifi cantly lower during end-expiration compared to end-inspiration. The LES pressure increased during the Valsalva maneuver and forced inspiration. With the patients in supine position the EP was positive during normal spontaneous breathing and during mechanical ventilation but was negative during forced inspiration. The EP increased signifi cantly during PEEP.

Conclusion: High-resolution solid-state manometry is a valuable tool for studying esophageal function. Lower esophageal sphincter pressure and barrier pressure decreased during anesthesia induction and were signifi cantly lower in obese compared to non-obese patients. However, barrier pressure remained positive in all patients. When evaluating the risk for regurgitation, the lowest lower esophageal sphincter pressure and barrier pressure are found during end-expiration. PEEP during anesthesia increased esophageal pressures and may therefore decrease the risk for passive regurgitation.

Place, publisher, year, edition, pages
Örebro: Örebro universitet , 2010. , 48 p.
Series
Örebro Studies in Medicine, ISSN 1652-4063 ; 46
Keyword [en]
Lower esophageal sphincter, upper esophageal sphincter, barrier pressure, obesity, high-resolution solid-state manometry, anesthesia
National Category
Medical and Health Sciences Surgery Anesthesiology and Intensive Care
Research subject
Surgery; Anaesthesiology
Identifiers
URN: urn:nbn:se:oru:diva-11269ISBN: 978-91-7668-743-7 (print)OAI: oai:DiVA.org:oru-11269DiVA: diva2:327250
Public defence
2010-09-24, Wilandersalen, Universitetssjukhuset, Örebro, 09:00
Opponent
Supervisors
Available from: 2010-06-28 Created: 2010-06-28 Last updated: 2017-10-18Bibliographically approved
List of papers
1. Effects of propofol on oesophageal sphincters: a study on young and elderly volunteers using high-resolution solid-state manometry
Open this publication in new window or tab >>Effects of propofol on oesophageal sphincters: a study on young and elderly volunteers using high-resolution solid-state manometry
2011 (English)In: European Journal of Anaesthesiology, ISSN 0265-0215, E-ISSN 1365-2346, Vol. 28, no 4, 273-278 p.Article in journal (Refereed) Published
Abstract [en]

BACKGROUND AND OBJECTIVE:

The oesophageal sphincters play an important role in protecting the airway. During manometric studies, administration of an anxiolytic agent is often required to make insertion of the catheter acceptable for the patient. The anxiolytic should not affect the results of the measurements. This study evaluates the effects of two different doses of propofol on the pressures in the oesophageal sphincters. The effect of increased abdominal pressure was also studied.

METHODS:

Twenty healthy volunteers, 10 young (mean age 25 years) and 10 elderly (mean age 71 years), were recruited. The effects of a low dose of propofol [0.3 mg kg(-1) intravenously (i.v.)] and a high dose of propofol (young group 0.9 mg kg(-1) i.v. and elderly group 0.6 mg kg(-1) i.v.) were studied with and without external abdominal pressure.

RESULTS:

There were no statistically significant changes in lower oesophageal sphincter (LOS) pressure after the low dose of propofol. After the high dose, there was an increase in LOS pressure, which was statistically significant in the young group (P < 0.05). The upper oesophageal sphincter (UOS) pressure decreased after both doses of propofol (P < 0.01 for the higher dose and P < 0.05 for the lower dose).

CONCLUSION:

A low dose of propofol (0.3 mg kg(-1) i.v.) leaves the LOS unaffected in young and elderly volunteers and can be used safely as an anxiolytic agent during studies of the LOS without influencing the results. However, the UOS is more sensitive to the effects of propofol and we do not recommend the use of propofol as an anxiolytic agent during manometric studies of the UOS.

Place, publisher, year, edition, pages
Lippincott Williams & Wilkins, 2011
National Category
Medical and Health Sciences Anesthesiology and Intensive Care
Research subject
Anaesthesiology
Identifiers
urn:nbn:se:oru:diva-15384 (URN)10.1097/EJA.0b013e3283413211 (DOI)000288196000009 ()21119519 (PubMedID)2-s2.0-79953874254 (Scopus ID)
Available from: 2011-04-26 Created: 2011-04-26 Last updated: 2017-12-11Bibliographically approved
2. High-resolution solid-state manometry of the upper and lower esophageal sphincters during anesthesia induction: a comparison between obese and non-obese patients
Open this publication in new window or tab >>High-resolution solid-state manometry of the upper and lower esophageal sphincters during anesthesia induction: a comparison between obese and non-obese patients
2010 (English)In: Anesthesia and Analgesia, ISSN 0003-2999, E-ISSN 1526-7598, Vol. 111, no 1, 149-153 p.Article in journal (Refereed) Published
Abstract [en]

BACKGROUND: The prevalence of obesity has increased dramatically in recent decades. The gastrointestinal changes associated with obesity have clinical significance for the anesthesiologist in the perioperative period. The lower esophageal sphincter and the upper esophageal sphincter play a central role in preventing regurgitation and aspiration. The effects of increased intra-abdominal pressure during anesthesia on the lower esophageal sphincter and the upper esophageal sphincter in obese patients are unknown. In the present study we evaluated, with high-resolution solid-state manometry, the upper esophageal sphincter, lower esophageal sphincter, and barrier pressure (BrP) (lower esophageal pressure - gastric pressure) in obese patients during anesthesia induction and compared them with pressures in non-obese patients. METHODS: We studied 28 patients, ages 18 to 72 years, 14 with a body mass index >= 35kg/m(2), who were undergoing laparoscopic gastric bypass, and 14 with a body mass index <= 30kg/m(2), who were undergoing laparoscopic cholecystectomy, using high-resolution solid-state manometry. RESULTS: Upper esophageal sphincter pressure decreased during anesthesia induction in both groups. Lower esophageal sphincter pressure decreased in both groups during anesthesia induction, and it was significantly lower in obese patients than in non-obese patients. The BrP decreased in both groups and was significantly lower in the obese group than in the non-obese group. The BrP remained positive at all times in both groups. CONCLUSION: Lower esophageal sphincter and BrPs decreased in both obese and non-obese patients during anesthesia induction, but were significantly lower in obese patients. Although the BrP was significantly lower, it remained positive in all patients. (Anesth Analg 2010;111:149-53)

National Category
Medical and Health Sciences Surgery
Research subject
Surgery
Identifiers
urn:nbn:se:oru:diva-15389 (URN)10.1213/ANE.0b013e3181e1a71f (DOI)000279281500027 ()
Available from: 2011-04-26 Created: 2011-04-26 Last updated: 2017-12-11Bibliographically approved
3. Body positions and esophageal sphincter pressures in obese patients during anesthesia
Open this publication in new window or tab >>Body positions and esophageal sphincter pressures in obese patients during anesthesia
2010 (English)In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 54, no 4, 458-463 p.Article in journal (Refereed) Published
Abstract [en]

Background: The lower esophageal sphincter (LES) and the upper esophageal sphincter (UES) play a central role in preventing regurgitation and aspiration. The aim of the present study was to evaluate the UES, LES and barrier pressures (BP) in obese patients before and during anesthesia in different body positions.

Methods: Using high-resolution solid-state manometry, we studied 17 patients (27-63 years) with a BMI>or=35 kg/m(2) who were undergoing a laparoscopic bariatric surgery before and after anesthesia induction. Before anesthesia, the subjects were placed in the supine position, in the reverse Trendelenburg position (+20 degrees) and in the Trendelenburg position (-20 degrees). Thereafter, anesthesia was induced with remifentanil and propofol and maintained with remifentanil and sevoflurane, and the recordings in the different positions were repeated.

Results: Before anesthesia, there were no differences in UES pressure in the different positions but compared with the other positions, it increased during the reverse Trendelenburg during anesthesia. LES pressure decreased in all body positions during anesthesia. The LES pressure increased during the Trendelenburg position before but not during anesthesia. The BP remained positive in all body positions both before and during anesthesia.

Conclusion: LES pressure increased during the Trendelenburg position before anesthesia. This effect was abolished during anesthesia. LES and BPs decreased during anesthesia but remained positive in all patients regardless of the body position.

Place, publisher, year, edition, pages
Malden, USA: Wiley-Blackwell Publishing Inc., 2010
National Category
Medical and Health Sciences Anesthesiology and Intensive Care
Research subject
Anaesthesiology
Identifiers
urn:nbn:se:oru:diva-11649 (URN)10.1111/j.1399-6576.2009.02158.x (DOI)000274932800012 ()19912128 (PubMedID)2-s2.0-77649215976 (Scopus ID)
Available from: 2010-08-27 Created: 2010-08-27 Last updated: 2017-12-12Bibliographically approved
4. Effects of different respiratory maneuvers on esophageal sphincters in obese patients before and during anesthesia
Open this publication in new window or tab >>Effects of different respiratory maneuvers on esophageal sphincters in obese patients before and during anesthesia
Show others...
2010 (English)In: Acta Anaesthesiologica Scandinavica, ISSN 0001-5172, E-ISSN 1399-6576, Vol. 54, no 10, 1204-1209 p.Article in journal (Refereed) Published
Abstract [en]

Background: Data on esophageal sphincters in obese individuals during anesthesia are sparse. The aim of the present study was to evaluate the effects of different respiratory maneuvers on the pressures in the esophagus and esophageal sphincters before and during anesthesia in obese patients.

Methods: Seventeen patients, aged 28-68 years, with a BMI >= 35 kg/m2, who were undergoing a laparoscopic gastric by-pass surgery, were studied, and pressures from the hypopharynx to the stomach were recorded using high-resolution solid-state manometry. Before anesthesia, recordings were performed during normal spontaneous breathing, Valsalva and forced inspiration. The effects of anesthesia induction with remifentanil and propofol were evaluated, and positive end-expiratory pressure (PEEP) 10 cmH(2)O was applied during anesthesia.

Results: During spontaneous breathing, the lower esophageal sphincter (LES) pressure was significantly lower during end-expiration compared with end-inspiration (28.5 +/- 7.7 vs. 35.4 +/- 10.8 mmHg, P < 0.01), but barrier pressure (BrP) and intra-gastric pressure (IGP) were unchanged. LES, BrP (P < 0.05) and IGP (P < 0.01) decreased significantly during anesthesia. BrP remained positive in all patients. IGP increased during Valsalva (P < 0.01) but was unaffected by PEEP. Esophageal pressures were positive during both spontaneous breathing and mechanical ventilation. Esophageal pressures increased during PEEP from 9.4 +/- 3.8 to 11.3 +/- 3.3 mmHg (P < 0.01).

Conclusion: During spontaneous breathing, the LES pressure was the lowest during end-expiration but there were no differences in BrP and IGP. LES, BrP and IGP decreased during anesthesia but BrP remained positive in all patients. During the application of PEEP, esophageal pressures increased and this may have a protective effect against regurgitation.

Place, publisher, year, edition, pages
Malden, USA: Wiley-Blackwell, 2010
National Category
Medical and Health Sciences Infectious Medicine
Research subject
Medicine
Identifiers
urn:nbn:se:oru:diva-12872 (URN)10.1111/j.1399-6576.2010.02305.x (DOI)000282687400007 ()20840514 (PubMedID)2-s2.0-78650198233 (Scopus ID)
Available from: 2011-01-05 Created: 2011-01-03 Last updated: 2017-12-11Bibliographically approved

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