RÉSUMÉ
BACKGROUND: The ideal tidal volume (TV) during one-lung ventilation (OLV) remains controversial. High TVs may increase the incidence of postoperative lung injury after thoracic surgery. There is nonetheless little evidence that the use of low TV during OLV will fail to provide adequate arterial oxygenation. We evaluated the influence of low (5 mL/kg-1) and high (10 mL/kg-1) TV on arterial oxygenation during one-lung ventilation in clinical conditions. METHODS: A hundred patients scheduled for lung surgery were studied. Patients were randomly assigned to either 30 minutes of one-lung ventilation with a TV of 10 mL/kg-1 at a rate of 10 breaths/minute (Group 10, N.=50) or a TV of 5 mL/kg-1 with 5 cmH2O PEEP at a rate of 20 breaths/minute (Group 5, N.=50). According to the rules of crossover design during the subsequent 30 minutes, each patient received the alternative management. Arterial blood partial pressures, hemodynamic responses, and ventilatory parameters were recorded. Results are presented as means ± SDs; P<0.05 was considered statistically significant. RESULTS: PaO2 was unaffected by TV (10 mL/kg-1: 218±106 versus 5 mL/kg-1: 211±119 mmHg, P=0.29). Calculated intrapulmonary shunt fraction was also similar with each TV during OLV (5 mL/kg-1: 25±9% versus 10 mL/kg-1: 24±8%, p=0.14). In contrast, low TV significantly increased PaCO2 (10 mL/kg-1: 39±6 versus 5 mL/kg-1: 44±8 mmHg, P<0.001). There were significant differences both in peak (10 mL/kg-1: 27±6 versus 5 mL/kg-1: 21±5 cmH2O, P<0.001) and plateau airway pressure values (10 mL/kg-1: 22±6 versus 5 mL/kg-1: 18±5 cmH2O, P<0.001) during OLV. CONCLUSION: Low TV (5 mL/kg-1) accompanied by 5 cmH2O PEEP provides comparable arterial oxygenation and intrapulmonary shunt fraction during one-lung ventilation as higher TV (10 mL/kg-1) without PEEP.
Sujet(s)
Ventilation sur poumon unique/méthodes , Consommation d'oxygène/physiologie , Procédures de chirurgie thoracique/méthodes , Volume courant/physiologie , Sujet âgé , Anesthésie générale , Études croisées , Femelle , Humains , Mâle , Adulte d'âge moyen , Ventilation à pression positive , Soins postopératoires , Études prospectivesRÉSUMÉ
BACKGROUND: The role of gravity in the redistribution of pulmonary blood flow during one-lung ventilation (OLV) has been questioned recently. To address this controversial but clinically important issue, we used an experimental approach that allowed us to differentiate the effects of gravity from the effects of hypoxic pulmonary vasoconstriction (HPV) on arterial oxygenation during OLV in patients scheduled for thoracic surgery. METHODS: Forty patients with chronic obstructive pulmonary disease scheduled for right lung tumour resection were randomized to undergo dependent (left) one-lung ventilation (D-OLV; n=20) or non-dependent (right) one-lung ventilation (ND-OLV; n=20) in the supine and left lateral positions. Partial pressure of arterial oxygen (PaO2) was measured as a surrogate for ventilation/perfusion matching. Patients were studied before surgery under closed chest conditions. RESULTS: When compared with bilateral lung ventilation, both D-OLV and ND-OLV caused a significant and equal decrease in PaO(2) in the supine position. However, D-OLV in the lateral position was associated with a higher PaO2 as compared with the supine position [274.2 (77.6) vs. 181.9 (68.3) mmHg, P<0.01, analysis of variance (ANOVA)]. In contrast, in patients undergoing ND-OLV, PaO2 was always lower in the lateral as compared with the supine position [105.3 (63.2) vs. 187 (63.1) mmHg, P<0.01, ANOVA]. CONCLUSION: The relative position of the ventilated vs. the non-ventilated lung markedly affects arterial oxygenation during OLV. These data suggest that gravity affects ventilation-perfusion matching independent of HPV.
Sujet(s)
Gravitation , Oxygène/sang , Positionnement du patient , Posture/physiologie , Broncho-pneumopathie chronique obstructive/physiopathologie , Ventilation artificielle/méthodes , Sujet âgé , Interventions chirurgicales non urgentes , Femelle , Humains , Soins peropératoires , Poumon/physiopathologie , Tumeurs du poumon/chirurgie , Mâle , Adulte d'âge moyen , Surveillance peropératoire , Pression partielle , Pneumonectomie , Circulation pulmonaire , Ventilation pulmonaire , Tests de la fonction respiratoire , Décubitus dorsal/physiologieRÉSUMÉ
BACKGROUND: There are no guidelines on ventilation modes in morbidly obese patients. We investigated the effects of volume-controlled (VCV) and pressure-controlled ventilation (PCV) on gas exchange, respiratory mechanics, and cardiovascular responses in laparoscopic gastric banding procedures. METHODS: After Institutional Review Board approval, 24 adult consenting patients scheduled for laparoscopic gastric banding were studied. Anesthesia was standardized using remifentanil, propofol, rocuronium, and sevoflurane. All patients started with VCV with a tidal volume of 10 ml kg(-1) ideal body weight, respiratory rate adjusted to obtain an end-tidal carbon dioxide of 35-40 mmHg, positive end-expiratory pressure of 5 cmH2O, an inspiratory pause of 10% and an inspiratory/expiratory ratio of 1:2. Fifteen minutes after pneumoperitoneum, the patients were randomly allocated to two groups. In Group VCV (n = 12), ventilation was with the same parameters. In Group PCV (n = 12), the airway pressure was set to provide a tidal volume of 10 ml kg(-1) ideal body weight without exceeding 35 cm H2O. Respiratory rate was adjusted to keep an end-tidal carbon dioxide of 35-40 mmHg. Arterial blood samples were drawn after surgical positioning and 15 min after allocation. Analysis of variance (ANOVA) was used for statistical analysis. RESULTS: With constant minute ventilation, VCV generates equal airway pressures and cardiovascular effects with a lower PaCO2 as compared to PCV (42.5 (5.2) mmHg versus 48.9 (4.3) mmHg, p < 0.01 ANOVA). Arterial oxygenation remained unchanged. CONCLUSIONS: VCV and PCV appear to be an equally suited ventilatory technique for laparoscopic procedures in morbidly obese patients. Carbon dioxide elimination is more efficient when using VCV.
Sujet(s)
Gastroplastie , Laparoscopie , Obésité morbide/chirurgie , Ventilation artificielle/méthodes , Adulte , Pression sanguine , Femelle , Rythme cardiaque , Humains , Mâle , Adulte d'âge moyen , Ventilation à pression positive , Échanges gazeux pulmonaires , Mécanique respiratoireRÉSUMÉ
Lactic acidosis is a common problem in the peri-operative period. During extensive surgery we frequently have an augmentation of lactic acid most often on the basis of hypoperfusion. Normally, a rise in serum lactate level causes a fall in blood pH, and this metabolic acidosis is accompanied by a high anion gap. In this case report a perioperative rise in lactic acid and an elevation in serum pH in a patient during meningeal tumour surgery is presented.
Sujet(s)
Acidose lactique/étiologie , Traitement par apport liquidien/effets indésirables , Tumeurs des méninges/chirurgie , Méningiome/chirurgie , Issue fatale , Femelle , Humains , Concentration en ions d'hydrogène , Acide lactique/sang , Adulte d'âge moyen , Soins périopératoiresRÉSUMÉ
More and more anesthesia machines are foreseen with spirometry monitoring. Nevertheless, the use of such equipment needs some interpretation skills for the displayed curves and numerical values otherwise it remains just a disturbing gadget rather than a powerful tool. This review explains in his first part the basic principles of interpretation of the spirometric data, and in the second part gives concrete examples of clinical situations.
Sujet(s)
Anesthésiologie , Soins périopératoires/instrumentation , Ventilation pulmonaire/physiologie , Ventilation artificielle/méthodes , Anesthésiologie/instrumentation , Anesthésiologie/méthodes , Humains , Monitorage physiologique/méthodes , Soins périopératoires/méthodes , Broncho-pneumopathie chronique obstructive/physiopathologie , SpirométrieRÉSUMÉ
Anaesthesia for patients with Leigh's syndrome has rarely been reported. Leigh's syndrome or subacute necrotizing encephalomyelopathy is a neurodegenerative disorder of infancy or childhood. Acute exacerbation with respiratory failure may accompany surgery and general anaesthesia. In this case report we describe the anaesthetic management of a 17 year old patient scheduled for spine surgery.
Sujet(s)
Anesthésie générale , Maladie de Leigh/complications , Scoliose/chirurgie , Adolescent , Anesthésiques par inhalation/administration et posologie , Anesthésiques intraveineux/administration et posologie , Femelle , Humains , Éthers méthyliques/administration et posologie , Surveillance peropératoire , Protoxyde d'azote/administration et posologie , Oxygène/administration et posologie , Pipéridines/administration et posologie , Propofol/administration et posologie , Rémifentanil , Ventilation artificielle , SévofluraneRÉSUMÉ
BACKGROUND: We measured lung mechanics and gas exchange during one-lung ventilation (OLV) of patients with chronic obstructive pulmonary disease, using three respiratory rates (RR) and unchanged minute volume. METHODS: We studied 15 patients about to undergo lung surgery, during anaesthesia, and placed in the lateral position. Ventilation was with constant minute volume, inspiratory flow and FIO2. For periods of 15 min, RR of 5, 10, and 15 bpm were applied in a random sequence and recordings were made of lung mechanics and an arterial blood gas sample was taken. Data were analysed with the repeated measures ANOVA and paired t-test with Bonferroni correction. RESULTS: PaO2 changes were not significant. At the lowest RR, PaCO2 decreased (from 42 (SD 4) mm Hg at RR 15-41 (4) mm Hg at RR 10 and 39 (4) mm Hg at RR 5, P<0.01), and end-tidal carbon dioxide increased (from 33 (5) mm Hg at RR 15 to 35 (5) mm Hg at RR 10 and 36 (6) mm Hg at RR 5, P<0.01). Intrinsic positive end-expiratory pressure (PEEPi) was reduced even with larger tidal volumes (from 6 (4) cm H2O at RR 15-5 (4) cm H2O at RR 10, and 3 (3) cm H2O at RR 5, P<0.01), most probably caused by increased expiratory time at the lowest RR. CONCLUSION: A reduction in RR reduces PEEPi and hypercapnia during OLV in anaesthetized patients with chronic obstructive lung disease.
Sujet(s)
Respiration avec pression positive intrinsèque/physiopathologie , Broncho-pneumopathie chronique obstructive/physiopathologie , Ventilation artificielle/méthodes , Mécanique respiratoire , Thoracotomie , Sujet âgé , Dioxyde de carbone/sang , Humains , Adulte d'âge moyen , Surveillance peropératoire , Oxygène/sang , Pression partielleRÉSUMÉ
The management of some problematic patients having thoracic surgery is among the most difficult challenges for the anesthesiologist. Increasingly complex operations are performed on seriously compromised patients because of the development of new surgical techniques and the anesthesiologists' awareness of surgical needs and requirements to provide a satisfactory and safe surgical field. In order to facilitate thoracic surgery, the single most important and valuable anesthetic technique used actually is one-lung ventilation. This article reviews the complex pathopysiology of one-lung ventilation.
Sujet(s)
Poumon/physiopathologie , Ventilation artificielle/effets indésirables , Humains , Intubation trachéale/effets indésirables , Respiration avec pression positive intrinsèque , Circulation pulmonaire , Ventilation artificielle/méthodesRÉSUMÉ
UNLABELLED: We compared the effects of position and fraction of inspired oxygen (F(IO)2) on oxygenation during thoracic surgery in 24 consenting patients randomly assigned to receive an F(IO)2 of 0.4 (eight patients, Group 0.4), 0.6 (eight patients, Group 0.6), or 1.0 (eight patients, Group 1.0) during the periods of two-lung (TLV) and one-lung ventilation (OLV) in the supine and lateral positions. TLV and OLV were maintained while the patients were first in the supine and then in the lateral position for 15 min each. Thereafter, respiratory mechanical data were obtained, and arterial blood gas samples were drawn. Pao2 decreased during OLV compared with TLV in both the supine and lateral positions. In all three groups, Pao2 was significantly higher during OLV in the lateral than in the supine position: 101 (72-201) vs 63 (57-144) mm Hg in Group 0.4; 268 (162-311) vs 155 (114-235) mm Hg in Group 0.6; and 486 (288-563) vs 301 (216-422) mm Hg in Group 1.0, respectively (P < 0.02, Wilcoxon's signed rank test). We conclude that, compared with the supine position, gravity augments the redistribution of perfusion as a result of hypoxic pulmonary vasoconstriction, when patients are in the lateral position, which explains the higher Pao2 during OLV. IMPLICATIONS: This study compares oxygenation during thoracic surgery during periods of two-lung and one-lung ventilation with patients in the supine and lateral positions when using three different fraction of inspired oxygen values. Arterial oxygen tension was decreased in all three groups during one-lung ventilation in comparison with the two-lung ventilation values, but the decrease was significantly less in the lateral, compared with the supine position.
Sujet(s)
Bronchopneumopathies obstructives/physiopathologie , Consommation d'oxygène/physiologie , Posture/physiologie , Ventilation artificielle , Adulte , Sujet âgé , Gazométrie sanguine , Méthode en double aveugle , Femelle , Humains , Poumon/chirurgie , Mâle , Adulte d'âge moyen , Oxygène/sang , Tests de la fonction respiratoire , Mécanique respiratoire/physiologie , Décubitus dorsal/physiologieRÉSUMÉ
This investigation analyzed the changes in inspiratory airway pressures during transition from two-lung to one-lung ventilation in patients tracheally intubated with a double-lumen endotracheal tube (DLT) using a classical method of intubation without fiberoptic bronchoscopy. All patients were anesthetized in a standardized fashion. Ventilation was accomplished with the Siemens 900 constant-flow mechanical ventilator (Solna, Sweden). Peak (Ppeak) and plateau (Pplateau) inspiratory airway pressures were recorded with an on-line respiratory monitor before and after clamping the tracheal limb of the DLT. The position of the DLTs was evaluated by fiberoptic bronchoscopy with the patient in supine position. Of the 51 intubations, the DLT was malpositioned in 15 cases (29.5%). Ppeak and Pplateau increased significantly when switched from two-lung ventilation to one-lung ventilation in both correctly and incorrectly positioned DLTs. When the DLT was in a correct position, Ppeak increased by a mean of 55.1% and Pplateau increased by a mean of 41.9%. When the DLT was malpositioned, this increase was significantly larger (74.9% and 68.8%, respectively). Three tests commonly used as markers of malpositioned DLTs were evaluated based on the data of this study, and it was established that, although the pressure differences related to position are statistically significant, as a single value, they cannot be used for clinical decision making.