| 1. |
- Ahlstrand, Rebecca, 1973-
(författare)
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Effects of anasthesia on esophageal sphincters
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The esophageal sphincters constitute the anatomical protection against pulmonary aspiration. The aim of this thesis was to study the esophageal sphincters and how they are affected by different components of emergency anesthesia using high-resolution solid-state manometry.The effect of propofol (0.3 mg/kg) was studied in young and elderly volunteers. Propofol can be given as an anxiolytic agent for manometric studies of the lower esophageal sphincter (LES) without affecting the results. However, propofol is not recommended for studies of the upper esophageal sphincter (UES).The effects of cricoid pressure (CP) and peripheral pain were studied in awake volunteers, with and without remifentanil infusion (5 ng/ml). Pain did not affect pressure in the LES, but CP or remifentanil induced a significant decrease in LES pressure. However, neither CP nor remifentanil affected the barrier pressure (LES-intra gastric pressure). When CP was applied during ongoing remifentanil infusion, no further decrease in LES pressure was measured. CP induced high pressures in the area of the UES independent of remifentanil infusion, indicating that CP is effective in preventing gastroesophageal regurgitation.Barrier pressure was also studied in anesthetized patients after rocuronium (0.6 mg/kg) administration and no decrease was measured. In addition, alfentanil (20 μ/kg) added during anesthesia induction with propofol did not decrease the barrier pressure.In conclusion, CP seems to be effective in preventing regurgitation and does not affect barrier pressure. Muscle relaxation with rocuronium does not risk gastro-esophageal integrity. In addition, opioids can be integrated, even during emergency anethesia, without increasing the risk for pulmonary aspiration.
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| 2. |
- Ahlstrand, Rebecca, 1973-, et al.
(författare)
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Effects of cricoid pressure and remifentanil on the esophageal sphincters using high-resolution solid-state manometry
- 2011
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Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley-Blackwell. - 0001-5172 .- 1399-6576. ; 55:2, s. 209-215
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Cricoid pressure has been shown to decrease the pressure in the lower esophageal sphincter (LES), increasing the risk of aspiration. Whether this reaction is due to pain associated with the application of cricoid pressure has not been studied. The aim of this study was to compare the effects of cricoid pressure with those of peripheral pain on pressures in the LES, and to study whether remifentanil influences these effects. Data from the upper esophageal sphincter (UES) are also described.METHODS: Continuous solid-state manometry was performed in 14 healthy volunteers. Initially, the effect of remifentanil (target-controlled infusion with a plasma target concentration of 5.0 ng/ml) was studied, and thereafter, the effects of cricoid pressure and peripheral pain stimulation (cold stimulation). Finally, these two interventions were repeated under ongoing remifentanil infusion.RESULTS: Remifentanil decreased the LES pressure significantly [ΔP-6.5 mmHg, 95% confidence interval (95% CI) -1.7 to -11.2]. Cricoid pressure application decreased the LES pressure significantly (ΔP-3.7 mmHg, 95% CI -1.4 to 6.1), whereas peripheral pain did not (ΔP 1.2 mmHg, 95% CI -3.5 to 1.1). Under ongoing remifentanil infusion, no cricoid pressure-induced LES relaxation was observed. Cricoid pressure induced high pressures in the area of the UES, 215.7 (±91.2) mmHg without remifentanil vs. 219.4 (±74.2) mmHg with remifentanil.CONCLUSIONS: Remifentanil as well as cricoid pressure per se induced decreases in LES pressure. However, cricoid pressure-induced changes of the barrier pressure were not significant whether induced with or without an infusion of remifentanil.
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| 3. |
- Ahlstrand, Rebecca, 1973-, et al.
(författare)
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High resolution solid-state manometry of the effect of rocuronium on esophagogastric junction integrity
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background: The pressure in the lower esophageal sphincter (LES) is partly dependent on striated muscles derived from the crural portion of the diaphragm. The effect of neuromuscular blockade on the integrity of the esophagogastric junction is not well studied. We conducted a prospective interventional study to determine the effect of rocuronium on the pressure in the LES and the barrier pressure (LES pressure – intra gastric pressure). We also studied the effect of positive pressure ventilation on the barrier pressure after neuromuscular blockade with rocuronium.Methods: Fourteen patients classified as ASA I or II (aged 18-75 years) who presented for elective surgery (11 cholecystectomy, 3 inguinal hernia) participated in the study. Esophageal manometry was performed after anesthetization with propofol, fentanyl and sevoflurane. After the insertion of a laryngeal mask airway, the patients breathed spontaneously for one minute. Rocuronium was administrated and the patients observed during the onset of apnea and during one minute of apnea and complete neuromuscular blockade. Volume controlled positive pressure ventilation followed.Results: Muscle relaxation with rocuronium showed no significant changes in barrier pressure comparing the pressure immediately before rocuronium administration with the pressure obtained at the time point of 0% TOF. Conversion to positive pressure ventilation did not change the barrier pressure with inspiration or expiration. The greatest decrease in barrier pressure was measured after inducing anesthesia when comparing pressures during inspiration (P< 0.01)
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| 4. |
- Ahlstrand, Rebecca, 1973-, et al.
(författare)
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Integrity of the esophagogastric junction during propofol induction with and without remifentanil : a double-blind,randomized, crossover study in volunteers
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Context: Practice varies regarding the use of opioids during rapid sequence induction. Controversy exists as to whether opioids may increase the risk of pulmonary aspiration by decreasing the barrier pressure (lower oesophageal sphincter pressure – intragastric pressure).Objectives: To evaluate the effects of adding alfentanil during anaesthesia induction with propofol with respect to the barrier pressure in the oesophagogastric junction.Participants and Setting: Seventeen healthy volunteers (11 males and 6 females) participated in a double-blind, randomised, crossover trial at the University Hospital in Örebro, Sweden.Interventions and outcome measures: The volunteers were anaesthetised on two different occasions, randomly assigned to receive either alfentanil 20 g kg ˉ1 or an equivalent amount of saline, administered intravenously, one minute before induction with propofol 2 mg kg ˉ1. One minute after propofol administration, a cricoid pressure of 30N was applied. The primary outcome was the difference in the change in barrier pressure between the alfentanil and the placebo occasion one minute after propofol administration. The secondary outcomes were differences in the changes in barrier pressure one minute after alfentanil or placebo administration and during ongoing cricoid pressure application.Results: There were no statistically significant differences in barrier pressure, at any time point, between anaesthesia induction with alfentanil and propofol compared with induction with placebo and propofol. The barrier pressure never decreased to less than 2.4 mmHg in any volunteer.Conclusion: Our study showed no increased risk regarding the integrity of the gastrooesophageal junction when alfentanil is added during an induction with propofol in volunteers. This supports the practice of adding opioids as adjuvants during rapid sequence induction.
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| 5. |
- Ander, Fredrik, 1978-, et al.
(författare)
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Does the β-receptor antagonist esmolol have analgesic effects? : A randomised placebo-controlled cross-over study on healthy volunteers undergoing the cold pressor test
- 2018
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Ingår i: European Journal of Anaesthesiology. - : Lippincott Williams & Wilkins. - 0265-0215 .- 1365-2346. ; 35:3, s. 165-172
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Esmolol may attenuate the sympathetic response to pain and reduce postoperative opioid consumption. It is not clear whether esmolol has an analgesic effect per se.OBJECTIVES: The aim of this study was to evaluate the analgesic effect of esmolol in the absence of anaesthetics and opioids. We tested the hypothesis that esmolol would reduce the maximum pain intensity perceived during the cold pressor test (CPT) by 2 points on a 0 to 10 numeric pain rating scale (NRS) compared to placebo.DESIGN: Randomised, placebo-controlled cross-over study.SETTING: Postoperative recovery area, Örebro University Hospital. Study period, November 2013 to February 2014.PARTICIPANTS: Fourteen healthy volunteers. Exclusion criteria included ongoing medication, pregnancy and breastfeeding and participation in other medical trials.INTERVENTIONS: At separate study sessions, participants received interventions: esmolol (0.7 mg kg bolus over 1 min followed by infusion at 10 μg kg min); 0.9% normal saline bolus then remifentanil infusion at 0.2 μg kg min and 0.9% normal saline bolus and infusion according to a random sequence. All infusions were administered over 30 min.MAIN OUTCOME MEASURES: Perceived maximum pain intensity score, pain tolerance and haemodynamic changes during CPT, and occurrence of side-effects to interventions compared to placebo, respectively.RESULTS: Esmolol did not reduce perceived pain intensity or pain tolerance during the CPT. The NRS-max score was similar for esmolol, 8.5 (±1.4) and placebo, 8.4 (±1.3). The mean difference was 0.1 [95% confidence interval (-1.2 to 1.4)], P value equal to 0.83. Remifentanil significantly reduced NRS-max scores, 5.4 (±2.1) compared to placebo, [mean difference -3.1 (95% confidence interval (-4.4 to -1.8)), P < 0.001]. Side-effects were seen with remifentanil but not with esmolol.CONCLUSION: No direct analgesic effect of esmolol could be demonstrated in the present study. The postoperative opioid-sparing effect demonstrated in previous studies, could therefore be secondary to other factors such as avoidance of opioid-induced hyperalgesia, synergy with coadministered opioids or altered pharmacokinetics of those drugs.TRIAL REGISTRATION: European clinical trials database, https://eudract.ema.europa.eu/, EudraCT no. 2011-005780-24.
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| 6. |
- Ander, Fredrik, 1978-, et al.
(författare)
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Effects of Esmolol on the Esophagogastric Junction : A Double-Blind, Randomized, Crossover Study on 14 Healthy Volunteers
- 2017
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Ingår i: Anesthesia and Analgesia. - Philadelphia, USA : Lippincott Williams & Wilkins. - 0003-2999 .- 1526-7598. ; 125:4, s. 1184-1190
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Passive regurgitation may occur throughout the perioperative period, increasing the risk for pulmonary aspiration and postoperative pulmonary complications. Hypnotics and opioids, especially remifentanil, that are used during anesthesia have been shown to decrease the pressure in the esophagogastric junction (EGJ), that otherwise acts as a barrier against passive regurgitation of gastric contents. Esmolol, usually used to counteract tachycardia and hypertension, has been shown to possess properties useful during general anesthesia. Like remifentanil, the beta-1-adrenoreceptor antagonist may be used to attenuate the stress reaction to tracheal intubation and to modify perioperative anesthetic requirements. It may also reduce the need for opioids in the postoperative period. Its action on the EGJ is however unknown. The aim of this trial was to compare the effects of esmolol and remifentanil on EGJ pressures in healthy volunteers, when administrated as single drugs.METHODS: Measurements of EGJ pressures were made in 14 healthy volunteers using high resolution solid-state manometry. Interventions were administered in a randomized sequence and consisted of esmolol that was given IV as a bolus dose of 1 mg/kg followed by an infusion of 10 mu g.kg(-1).minute(-1) over 15 minutes, and remifentanil with target-controlled infusion of 4 ng/mL over 15 minutes. Interventions were separated by a 20-minute washout period. Analyses of EGJ pressures were performed at baseline, and during drug administration at 2 (T2) and 15 minutes (T15). The primary outcome was the inspiratory EGJ augmentation, while the inspiratory and expiratory EGJ pressures were secondary outcomes.RESULTS: There was no effect on inspiratory EGJ augmentation when comparing remifentanil and esmolol (mean difference -4.0 mm Hg [-9.7 to 1.7]; P = .15). In contrast, remifentanil significantly decreased both inspiratory and expiratory pressures compared to esmolol (-12.2 [-18.6 to 5.7]; P = .003 and 8.0 [-13.3 to 2.8]; P = .006).CONCLUSIONS: Esmolol, compared with remifentanil, does not affect EGJ function. This may be an advantage regarding passive regurgitation and esmolol may thus have a role to play in anesthesia where maintenance of EGJ barrier function is of outmost importance.
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| 7. |
- Ander, Fredrik, 1978-
(författare)
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Perioperative complications in obese patients : A thesis on risk reducing strategies
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Aspiration of gastric content and delayed or failed intubation are the leading causes of anesthesia-related mortality and morbidity. In the recovery period, airway obstruction with subsequent hypoxia is a relatively common cause of morbidity, and is highly associated to the amount of opioids administered, especially in obese patients.The overall aim of this thesis was to study these risk factors for airway complications and postoperative hypoxia in obese patients, and to evaluate possible strategies for their prevention.In Study I, intubation times and incidence of failed intubation in obese patients were compared between direct laryngoscopy and videolaryngoscopy with the Stortz® C-MAC™. In Studies II and III, the effect of esmolol vs. remifentanil on the esophageal junction, and the possible analgesic properties of low-dose esmolol vs. placebo were evaluated using high-resolution manometry and the cold pressor test, respectively. Finally, in Study IV, the possible opioid-sparing effect of esmolol after laparoscopic gastric bypass surgery was evaluated.The use of videlaryngoscopy did not shorten intubation times, however appeared to reduce the incidence of failed intubation. Our results also show that esmolol has a favorable profile, compared to remifentanil, with regard to the protection against passive regurgitation and aspiration of gastric content. No analgesic effect of low-dose esmolol was however demonstrated. The intraoperative administration of esmolol instead of remifentanil also did not reduce the requirement of morphine for treatment of post-operative pain.The use of Stortz® C-MAC™ may be recommended for intubation of obese patients. Further studies are however required to clarify the possible role of esmolol in anesthesia.
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| 8. |
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| 9. |
- Ander, Fredrik, 1978-, et al.
(författare)
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Time-to-intubation in obese patients : A randomized study comparing direct laryngoscopy and videolaryngoscopy in experienced anaesthetists
- 2017
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Ingår i: Minerva Anestesiologica. - : Edizioni Minerva Medica. - 0375-9393 .- 1827-1596. ; 83:9, s. 906-913
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Airway management may be difficult in obese patients. Moreover, during prolonged intubation, oxygen desaturation develops rapidly. Videolaryngoscopy improves the view of the larynx, and the Storz® C-MACTM has been shown to be superior to other videolaryngoscopes in terms of intubation time in obese patients. However, no effort has been made to compare the Storz® C-MACTM with direct laryngoscopy. The aim of the study was to evaluate if the use of Storz® C-MACTM may reduce intubation time when compared to direct laryngoscopy (classic Macintosh® blade).METHODS: eighty patients with body mass index > 35kg/m2 were randomized to orotracheal intubation using either Macintosh® laryngoscope, or the Storz® C-MACTM with the standard Macintosh blade. Patients had no previous history of a difficult airway. Time- to-intubation (TTI) was defined as the time from the moment anaesthetist took the laryngoscope until end-tidal carbon dioxide was detected.RESULTS: no significant difference in TTI could be demonstrated between the two devices tested (mean difference -1.7s (95% CI -6.9 to 3.5s). All patients in the videolaryngoscopy group were successfully intubated with the allocated device, whereas five patients in the direct laryngoscopy group required an alternative device for successful intubation. No significant difference regarding the subjective difficulty of intubation and postoperative sore throat between groups was demonstrated.CONCLUSION: in obese patients the airway may be secured equally fast using direct laryngoscopy (Macintosh®) and with videolaryngoscopy using the Stortz® C-MACTM. The risk for failed intubation, however, appears to be greater with direct laryngoscopy, especially in male obese patients.
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| 10. |
- Bartha, Erzsebet, et al.
(författare)
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ASA classification and surgical severity grading used to identify a high-risk population, a multicenter prospective cohort study in Swedish tertiary hospitals
- 2021
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Ingår i: Acta Anaesthesiologica Scandinavica. - : John Wiley & Sons. - 0001-5172 .- 1399-6576. ; 65:9, s. 1168-1177
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Tidskriftsartikel (refereegranskat)abstract
- Background: Identification of surgical populations at high risk for negative outcomes is needed for clinical and research purposes. We hypothesized that combining two classification systems, ASA (American Society of Anesthesiology physical status) and surgical severity, we could identify a high-risk population before surgery. We aimed to describe postoperative outcomes in a population selected by these two classifications system.Methods: Data were collected in a Swedish multicentre, time-interrupted prospective, consecutive cohort study. Eligibility criteria were age >= 18 years, ASA >= 3, elective or emergent, major to Xmajor/complex (Specialist Procedure Codes used in United Kingdom), gastrointestinal, urogenital or orthopaedic procedures. Postoperative morbidity was identified by the Postoperative Morbidity Survey on postoperative days 3 +/- 1, 7 +/- 1, 10 + 5 and graded for severity by the Clavien-Dindo system. Mortality was assessed at 30, 180 and 360 days.Results: Postoperative morbidity was 78/48/47 per cent on postoperative days 3/7/10. Majority of morbidities (67.5 per cent) were graded as >1 by Clavien-Dindo. Any type of postoperative morbidity graded >1 was associated with increased risk for death up to one year. The mortality was 5.7 per cent (61/1063) at 30 days, 13.3 per cent (142/1063) at 6 months and 19.1 per cent (160/1063) at 12 months.Conclusion: Severity classification as major to Xmajor/complex and ASA >= 3 could be used to identify a high-risk surgical population concerning postoperative morbidity and mortality before surgery. Combining the two systems future electronic data extraction is possible of a high-risk population in tertiary hospitals.
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