The Effects of Body Mass on Lung Volumes, Respiratory Mechanics, and Gas Exchange During General Anesthesia

Pelosi, Paolo; Croci, M.; Ravagnan, I; Tredici, Stefano; Pedoto, Alessia; Lissoni, Alfredo; Gattinoni, Luciano

doi:10.1097/00000539-199809000-00031

Cited by 207 publications

(124 citation statements)

References 23 publications

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“…Lung elastic recoil was not measured in this study, but previous studies suggest that it is increased in obesity. 27 It seems likely that the increase in lung elastic recoil in obese subjects can offset the effect of low lung volume, so that there is no unloading of airway smooth muscle, and thus no increase in maximal response.…”

Section: Discussionmentioning

confidence: 99%

“…The greater baseline stiffness of the respiratory system in the obese could be partly due to greater stiffness of the chest wall and the lung, which is particularly marked above a BMI of approximately 35 kg m À2 . 27 It is unlikely that methacholine had any direct effect on the chest wall, independent of the changes in inspiratory capacity, and thus the contribution of chest wall stiffness to the changes in reactance during challenge is likely to be small, but cannot be excluded. Reactance is highly sensitive to changes in operating lung volume, so that stiffness increases as lung volume increases.…”

Section: Perception Of Dyspneamentioning

confidence: 99%

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Effect of obesity on breathlessness and airway responsiveness to methacholine in non-asthmatic subjects

et al. 2007

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Background: Obesity is associated with increased prevalence and incidence of asthma, but the mechanism is unknown. Obesity reduces lung volumes, which can increase airway responsiveness, and increases resistive and elastic work of breathing, which can increase dyspnea. Objective: To determine if the intensity of dyspnea due to airway narrowing or if airway responsiveness is increased in obese, non-asthmatic subjects. Subjects: Twenty-three obese (BMI (body mass index) X30 kg m À2 ) and 26 non-obese (BMI o30 kg m À2 ) non-asthmatic subjects, aged between 18 and 70 years. Methods: High-dose methacholine challenge was used to determine the sensitivity and the maximal response to methacholine. Respiratory system resistance (Rrs) and reactance were measured, using the forced oscillation technique, as indicators of resistive and elastic loads during challenge. Perception of dyspnea was measured by the Borg score during challenge. Static lung volumes were measured by body plethysmography. Results: Static lung volumes were reduced in the obese subjects. There were no significant differences in the sensitivity or maximal response to methacholine between obese and non-obese subjects. The magnitude of change in Rrs was similar in both groups, but obese subjects had more negative reactance after challenge (P ¼ 0.002) indicating a greater elastic load. The intensity of dyspnea was greater in obese subjects (P ¼ 0.03). Conclusions: Obesity reduces lung volumes, but does not alter the sensitivity or maximal response to methacholine. However, obese subjects have enhanced perception of dyspnea, associated with greater apparent stiffness of the respiratory system, and may therefore be at greater risk of symptoms.

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Section: Discussionmentioning

confidence: 99%

Section: Perception Of Dyspneamentioning

confidence: 99%

Effect of obesity on breathlessness and airway responsiveness to methacholine in non-asthmatic subjects

et al. 2007

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“…These physiologic changes predispose the morbidly obese patient to rapid oxygen desaturation with the onset of apnea. 7 Association between obesity and a difficult airway…”

Section: Airway Patency and Respiratory Physiology In Obese Patientsmentioning

confidence: 99%

“…Ces changements physiologiques prédisposent le patient obèse morbide à une désaturation en oxygène rapide avec l'apparition de l'apnée. 7 …”

Section: Perméabilité Des Voies Aériennes Et Physiologie Respiratoireunclassified

Airway management and oxygenation in obese patients

Murphy

Wong

2013

Can J Anesth/J Can Anesth

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“…Respiratory problems are associated with morbid obesity, including obstructive apnea during sleep, decreased functional residual capacity and lung compliance and increased work of breathing. 2,3 Obese patients may be sensitive to the respiratory depressant effect of opioid analgesic drugs and more likely to require postoperative ventilation to avoid hypoxic episodes. 4 It has been recommended that opioid drugs be avoided for analgesia in the morbidly obese patient because of the risk of respiratory depression.…”

mentioning

confidence: 99%

Non-opioid analgesia improves pain relief and decreases sedation after gastric bypass surgery

Feld

Laurito

Beckerman

et al. 2003

Can J Anesth/J Can Anesth

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P Pu ur rp po os se e: : Several non-opioid drugs have been shown to provide analgesia during and after surgery. We compared sevoflurane anesthesia with fentanyl analgesia to sevoflurane and non-opioid drug treatment for gastric bypass surgery and recovery.M Me et th ho od ds s: : Thirty obese patients (body mass index > 50 kg·m -2 ) undergoing gastric bypass were randomized to receive sevoflurane anesthesia with either fentanyl or a non-opioid regimen including ketorolac, clonidine, lidocaine, ketamine, magnesium sulfate, and methylprednisolone. Morphine use by patient-controlled analgesia (PCA) pump and pain score measured by visual analogue scale were determined in the postanesthesia care unit (PACU) and for the first 16 hr after surgery. Sedation was evaluated in the PACU. Investigators assessing patient outcomes were blinded to the study group.R Re es su ul lt ts s: : Fentanyl treated patients were more sedated in the PACU compared to the non-opioid group. Non-opioid treated patients required 5.2 ± 2.6 mg·hr -1 morphine by PCA during their stay in the PACU while patients anesthetized with fentanyl used 7.8 ± 3.3 mg·hr -1 (P < 0.05). Fentanyl and non-opioid treated patients showed no difference in pain score one or 16 hr after surgery.C Co on nc cl lu us si io on n: : Our results show that non-opioid analgesia produced pain relief and less sedation during recovery from gastric bypass surgery compared to fentanyl. Objectif : On reconnaît à certains médicaments non-opioïdes des Résultats : La sédation, notée à la SDR, était plus importante chez les patients traités au fentanyl, comparés à ceux traités avec un médicament non-opioïde. Les patients traités aux non-opioïdes ont demandé 5,2 ± 2,6 mg·h -1 de morphine en AAC pendant leur séjour en SDR tandis que les patients anesthésiés au fentanyl en ont utilisé 7,8 ± 3,3 mg·h -1 (P < 0,05). Les scores de douleurs des patients des deux groupes n'ont présenté aucune différence, une ou 16 h après l'opération. Conclusion : L'analgésie avec des non opioïdes, comparé au fentanyl, a mieux soulagé la douleur et provoqué moins de sédation pendant la récupération qui suit un pontage gastrique.HE body mass index (BMI), calculated as the weight in kilograms divided by the height in metres squared, has been used in clinical and epidemiological studies as a predictor of health risk. 1 A BMI of 25 kg·m -2 is considered normal, > 30 kg·m -2 obese, > 35 kg·m -2 morbidly obese and > 55 kg·m -2 super morbidly obese. Respiratory problems are associated with morbid obesity, including obstructive apnea during sleep, decreased functional residual capacity and lung compliance and increased work of breathing. 2,3 Obese patients may be sensitive to the respiratory depressant effect of opioid analgesic drugs and more likely to require postoperative ventilation to avoid hypoxic episodes.

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The Effects of Body Mass on Lung Volumes, Respiratory Mechanics, and Gas Exchange During General Anesthesia

Abstract: The aim of this study was to investigate the influence of body mass on lung volumes, respiratory mechanics, and gas exchange during general anesthesia.

Cited by 207 publications

References 23 publications

Effect of obesity on breathlessness and airway responsiveness to methacholine in non-asthmatic subjects

Effect of obesity on breathlessness and airway responsiveness to methacholine in non-asthmatic subjects

Airway management and oxygenation in obese patients

Non-opioid analgesia improves pain relief and decreases sedation after gastric bypass surgery

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