Effects of desflurane and propofol on arterial oxygenation during one-lung ventilation in the pig

Background: Desflurane depresses hypoxic pulmonary vasoconstriction (HPV) in vitro. During one-lung ventilation (OLV), HPV may reduce venous admixture and ameliorate the decrease in arterial O₂ tension by diverting blood from the non-ventilated to the ventilated lung. Accordingly, this study compares the effects of desflurane with those of propofol on oxygenation during two-lung (TLV) and OLV in vivo. Methods: Ten pigs (25–30 kg) were premedicated (flunitrazepam 0.4 mg/kg im), anaesthetized (induction: propofol 2 mg/kg iv; maintenance: N₂O/O₂ 50%/50%, desflurane 3%, propofol 50 μg kg^?1 min^?1, and vecuronium 0.2 mg kg^?1 h^?1 iv), orally intubated and mechanically ventilated. Femoral arterial and thermodilution pulmonary artery catheters were placed, and the orotracheal tube was replaced by a left-sided 28-Ch double-lumen tube (DLT) via tracheotomy. After DLT placement, N₂O and propofol were discontinued, FiO₂ was increased to 0.85, and anaesthesia continued randomly with either desflurane (1 MAC) or propofol 200 μg kg^?1 min^?1. Using a cross-over design, in each animal the effects of a), changing from TLV to OLV (left lung) during both desflurane and propofol and b), the effects of changing between the two anaesthetics during OLV were studied. Results: When changing from TLV to OLV, PaO₂ decreased more (P<0.05) during desflurane (mean 75%) than during propofol (mean 60%). Changing between desflurane and propofol during OLV resulted in small but consistent (P<0.05) increases in PaO₂ (mean 15%) during propofol. Conclusion: Consistent with in vitro results on HPV, 1 MAC desflurane impaired in vivo oxygenation during OLV more than did propofol.     

Recurrent Laryngeal Nerve Monitoring During Esophagectomy and Mediastinal Lymph Node Dissection

Background  

Patients who undergo surgery to the esophagus and lungs are in jeopardy of recurrent laryngeal nerve (RLN) damage during the procedure. This study was designed to investigate the feasibility of intraoperative monitoring of the RLN for single-lung ventilation esophagus and lung surgery.     

丙泊酚抑制双腔支气管插管心血管反应的有效浓度

目的评价丙泊酚抑制双腔支气管插管心血管反应的有效浓度(effective concentration,EC)。方法纳入拟行全身麻醉单侧肺部手术的患者100例,按年龄分为青年组和中年组。青年组患者给予丙泊酚靶控输注(target controlled infusion,TCI)血浆浓度3.0 mg/L,中年组患者给予丙泊酚2.5 mg/L。根据前一例置入双腔支气管时情况,决定下一例丙泊酚浓度。根据最终观察结果,分析计算丙泊酚的有效浓度。结果青年组和中年组丙泊酚抑制双腔支气管插管心血管置入反应的半数效应浓度(median effective concentration,EC50)分别为3.594 mg/L(95%CI 1.992~3.594)和2.938 mg/L(95%CI 2.426~3.104),95%效应浓度(95%effective concentration,EC95)分别为4.031 mg/L(95%CI 3.810~4.917)和3.479 mg/L(95%CI 3.284~4.283)。结论青年组和中年组抑制双腔支气管插管心血管反应的丙泊酚血浆靶控浓度EC95分别为4.031 mg/L和3.479 mg/L。     

On-line monitoring of end-tidal propofol concentration in anesthetized patients

BACKGROUND: Propofol (2,6-diisopropylphenol) has some volatility, so it can be detected in expired breath of individuals receiving intravenous propofol. This study measured volatile propofol exhaled by patients and investigated the relation between exhaled and plasma propofol concentrations. METHODS: Nineteen patients with American Society of Anesthesiologists physical status I or II who were undergoing elective surgery participated in this two-part study. In study 1 (n = 11), anesthesia was induced with 2 mg/kg propofol, 0.1 mg/kg vecuronium, and 2 microg/kg fentanyl. After intubation, propofol was administered continuously for 60 min at each of three rates: 3, 6, and 9 mg x kg(-1) x h(-1). Blood samples were obtained just before each change in the infusion rate, and the plasma concentrations of propofol were measured. The exhaled propofol concentration was measured continuously by means of proton transfer mass spectrometry. End-tidal propofol concentrations during blood sampling were averaged and compared with plasma propofol concentrations. In study 2 (n = 8), after induction of anesthesia, patients received a bolus injection of 2 mg/kg propofol, and the exhaled propofol concentration was measured. RESULTS: Volatile propofol was detected in expired gas from all study patients. From study 1, the authors obtained 24 paired data points, i.e., concentrations of end-tidal and plasma propofol. With Bland-Altman analysis, bias +/- precision was 5.2 +/- 10.4 with 95% limits of agreement of -15.1 and 25.6. In study 2, the exhaled propofol concentration curve showed an obvious peak in all patients. CONCLUSIONS: Agreement between plasma and exhaled propofol concentrations suggests that proton transfer mass spectrometry can be used for real-time propofol monitoring.     

The Univent tube for single-lung ventilation in paediatric patients

A Univent bronchial blocker tube was used in a ten-year-old patient undergoing videothoracoscopy. Paediatric Univent tubes offer an alternative to balloon-tipped catheters for providing single-lung ventilation (SLV) in children too small for adult size double-lumen tubes.     

Mechanical ventilation post-bilateral lung transplantation: A scoping review

Background

Evidence from lung protective ventilation (LPV) in the acute respiratory distress syndrome has commonly been applied to guide periprocedural ventilation in lung transplantation. However, this approach may not adequately consider the distinctive features of respiratory failure and allograft physiology in the lung transplant recipient. This scoping review was conducted to systematically map the research describing ventilation and relevant physiological parameters post-bilateral lung transplantation with the aim to identify any associations with patient outcomes and gaps in the current knowledge base.

Methods

To identify relevant publications, comprehensive literature searches of electronic bibliographic databases were conducted with the guidance of an experienced librarian in MEDLINE, EMBASE, SCOPUS and the Cochrane Library. The search strategies were peer-reviewed using the PRESS (Peer Review of Electronic Search Strategies) checklist. The reference lists of all relevant review articles were surveyed. Publications were included in the review if they described relevant ventilation parameters in the immediate post-operative period, published between 2000 and 2022 and involved human subjects undergoing bilateral lung transplantation. Publications were excluded if they included animal models, only single-lung transplant recipients or only patients managed with extracorporeal membrane oxygenation.

Results

A total of 1212 articles were screened, 27 were subject to full-text review and 11 were included in the analysis. The quality of the included studies was assessed to be poor with no prospective multi-centre randomised controlled trials. The frequency of reported retrospective LPV parameters was as follows: tidal volume (82%), tidal volume indexed to both donor and recipient body weight (27%) and plateau pressure (18%). Data suggest that undersized grafts are at risk of unrecognised higher tidal volume ventilation indexed to donor body weight. The most reported patient-centred outcome was graft dysfunction severity in the first 72 h.

Conclusion

This review has identified a significant knowledge gap that indicates uncertainty regarding the safest ventilation practice in lung transplant recipients. The risk may be greatest in patients with established high-grade primary graft dysfunction and undersized allografts, and these factors may define a sub-group that warrants further investigation.     

The effects of increasing concentrations of desflurane on systemic oxygenation during one-lung ventilation in pigs.

During one-lung ventilation (OLV), hypoxic pulmonary vasoconstriction reduces venous admixture and attenuates the decrease in arterial O2 tension by diverting blood from the nonventilated to the ventilated lung. In vitro, increasing concentrations of desflurane depresses hypoxic pulmonary vasoconstriction in a dose-dependent manner. Accordingly, we investigated the effects of increasing concentrations of desflurane on oxygenation during OLV in vivo. Thirteen pigs (25-30 kg) were anesthetized (induction: propofol 2-3 mg/kg IV; maintenance: N2O/O2 50%/50%, desflurane 3%, propofol 50 microg x kg(-1) min(-1), and vecuronium 0.2 mg x kg(-1) x h(-1) IV), orotracheally intubated, and mechanically ventilated. After placement of femoral arterial and thermodilution pulmonary artery catheters, a leftsided, 28F, double-lumen tube was placed via tracheotomy. After double-lumen tube placement, N2O and desflurane were discontinued, propofol was increased to 200 microg x kg(-1) x min(-1), and the fraction of inspired oxygen was adjusted at 0.8. Anesthesia was then continued in random order with desflurane 5%, 10%, or 15% end-tidal concentrations while propofol was discontinued. Whereas mixed venous PO2, mean arterial pressure, cardiac output, and shunt fraction decreased in a dose-dependent manner, PaO2 remained unchanged with increasing concentrations of desflurane during OLV. These findings indicate that, in vivo, increasing concentrations of desflurane do not necessarily worsen oxygenation during OLV. IMPLICATIONS: Oxygenation during one-lung ventilation depends on reflex vasoconstriction in the nonventilated lung. In vitro, desflurane inhibits this reflex dose-dependently. Our results indicate that, in vivo, this does not necessarily translate to dose-dependent decreases in oxygenation during one-lung ventilation.     

Ketamine eliminates propofol pain but does not affect hemodynamics during induction with double-lumen tubes

Background and objective  

Propofol injection during induction of anesthesia induces pain. Ketamine has been shown to reduce the injection pain. However, ketamine has unfavorable adverse effects, including increased secretion production and hemodynamic responses, which might induce pulmonary or hemodynamic adverse events, especially in patients undergoing lung surgery who require a double-lumen tube (DLT). The aim of this study was to determine whether ketamine can safely reduce propofol injection pain during induction of anesthesia for lung surgery.     

On-line Monitoring of End-tidal Propofol Concentration in Anesthetized Patients

Background: Propofol (2,6-diisopropylphenol) has some volatility, so it can be detected in expired breath of individuals receiving intravenous propofol. This study measured volatile propofol exhaled by patients and investigated the relation between exhaled and plasma propofol concentrations.

Methods: Nineteen patients with American Society of Anesthesiologists physical status I or II who were undergoing elective surgery participated in this two-part study. In study 1 (n = 11), anesthesia was induced with 2 mg/kg propofol, 0.1 mg/kg vecuronium, and 2 [mu]g/kg fentanyl. After intubation, propofol was administered continuously for 60 min at each of three rates: 3, 6, and 9 mg [middle dot] kg-1 [middle dot] h-1. Blood samples were obtained just before each change in the infusion rate, and the plasma concentrations of propofol were measured. The exhaled propofol concentration was measured continuously by means of proton transfer mass spectrometry. End-tidal propofol concentrations during blood sampling were averaged and compared with plasma propofol concentrations. In study 2 (n = 8), after induction of anesthesia, patients received a bolus injection of 2 mg/kg propofol, and the exhaled propofol concentration was measured.

Results: Volatile propofol was detected in expired gas from all study patients. From study 1, the authors obtained 24 paired data points, i.e., concentrations of end-tidal and plasma propofol. With Bland-Altman analysis, bias +/- precision was 5.2 +/- 10.4 with 95% limits of agreement of -15.1 and 25.6. In study 2, the exhaled propofol concentration curve showed an obvious peak in all patients.     

Thoracoscopic microsurgical technique for vertebral surgery – anesthetic considerations

Background: The thoracoscopic microsurgical technique (TMT) for vertebral and spinal cord surgery is associated with the benefits of reduced postoperative pain, accelerated return to physical activity and reduced complication rates. However, because of the surgeon's requirement of a non-ventilated lung, it confronts the anesthesiologist with the need for extremely long duration of single-lung ventilation (SLV). Methods: We describe our experiences with 82 patients, whom we anesthetised from 1993 until 1996 for TMT. Because of the potential risk of depression of hypoxic pulmonary vasoconstriction during SLV by volatile anesthetics, we primarily used a total intravenous technique (55 patients). With more experience, we also used a combination of volatile and intravenous anesthetics (16 patients) and, finally, volatile anesthetics only (11 patients). Data from patients anesthetised for TMT were compared with data from 22 patients operated with open thoracotomy from 1984 until 1992. Results: While the operating time (290.1±133.2 min for TMT vs. 312.3±113.6 for thoracotomy) and the anesthesia time (431.2±140.3 for TMT vs. 416.4±102.1 for thoracotomy) showed no significant differences, the TMT required an extremely long time of SLV (270.2±133.2 min) to gain access to the spine using left-sided double-lumen tubes. While the oxygenation index (PaO₂/FiO₂), as a marker for pulmonary oxygenation capacity, decreased significantly after initiation of SLV for TMT, it was markedly enhanced with increasing duration (270.2+133.2 min) of SLV. Oxygenation index showed no significant difference when comparing the different anesthetic techniques for TMT. Conclusion: We conclude that despite the long duration of SLV, TMT is a reasonable alternative to open thoracotomy for thoracic neurosurgical spine procedures because of the substantial clinical benefits of accelerated return to physical activity, reduced complication rates and reduced intensive care unit and hospital stay.     

Determination of the pharmacodynamic interaction of propofol and dexmedetomidine during esophagogastroduodenoscopy in children

Objectives: Propofol is a sedative‐hypnotic drug commonly used to anesthetize children undergoing esophagogastroduodenoscopy (EGD). Dexmedetomidine is a highly selective alpha‐2 adrenergic receptor agonist that has been utilized in combination with propofol to provide anesthesia. There is currently no information regarding the effect of intravenous dexmedetomidine on the propofol plasma concentration–response relationship during EGD in children. This study aimed to investigate the pharmacodynamic interaction of propofol and dexmedetomidine when used in combination for children undergoing EGD. Methods: A total of 24 children undergoing EGD, ages 3–10 years, were enrolled in this study. Twelve children received dexmedetomidine 1 μg·kg^?1 given over 10 min as well as a continuous infusion of propofol delivered by a computer‐assisted target‐controlled infusion (TCI) system with target plasma concentrations ranging from 2.8 to 4.0 μg·ml^?1 (DEX group). Another group of 12 children undergoing EGD also received propofol administered by TCI targeting comparable plasma concentrations without dexmedetomidine (control group). We used logistic regression to predict plasma propofol concentrations at which 50% of the patients exhibited minimal response to stimuli (EC₅₀ for anesthesia). Results: The EC₅₀ ± se values in the control and DEX groups were 3.7 ± 0.4 μg·ml^?1 and 3.5 ± 0.2 μg·ml^?1, respectively. There was no significant shift in the propofol concentration–response curve in the presence of dexmedetomidine. Conclusion: The EC₅₀ of propofol required to produce adequate anesthesia for EGD in children was unaffected by a concomitant infusion of dexmedetomidine 1 μg·kg^?1 given over 10 min.     

Contribution from upper and lower airways to exhaled endogenous nitric oxide in humans

Endogenous nitric oxide (NO) is thought to regulate many biological functions, including pulmonary circulation and bronchomotion, and it has been found in exhaled air. Our aim was to study the excretion of NO in different parts of the respiratory system.
Exhaled concentrations of NO were measured by chemiluminescence in chronic tracheostomy outpatients (group 1), in patients admitted for minor abdominal surgery (group 2), and in patients with acute respiratory failure (ARF) during mechanical ventilation (group 3). In awake volunteers (group 4), 0.57 L/min gas was aspirated through the nasal cavity into the chemiluminescence device.
In group 1 (tracheostomy, n=5) we detected 16±2 (mean±s.c. mean) parts per billion (ppb) NO when exhaling through the mouth, and a lower ( P <0.05) value of 4.6±0.8 ppb NO when exhaling through the tracheostomy. Before anaesthesia, group 2 (n=11) exhibited 13±2.4 ppb NO in orally exhaled gas, increasing considerably during exhalation through the nose. Upon endotracheal intubation exhaled NO concentration dropped to 1.3±0.2 ppb ( P <0.05). In group 3 (ARF, n=7) tracheal NO concentrations were 0.8±0.2 ppb. In group 4 (volunteers, n=6) 394±23 ppb NO was recorded in air from the nasal cavity.
In both healthy subjects and patients with respiratory failure a significant NO excretion occurs in the lower airways and lungs. The upper airways, expecially the nose, contribute the largest amount of NO (>90%) to exhaled air. The physiological implications of an upper airway source of NO remain to be defined.     

Plasma propofol concentrations during orthotopic liver transplantation

Objective: The aim of this study was to investigate the changes in plasma concentrations of propofol in three phases (the paleohepatic, anhepatic, and neohepatic phases) during orthotopic liver transplantation (OLT) using target‐controlled infusion (TCI). Methods: Ten patients undergoing OLT without venovenous bypass were studied (age 29–53 years, weight 56–79 kg). After intubation, a non‐hypnotic target concentration of propofol 0.5 µg ml^?1 using a Diprifusor^® pump (Zeneca Pharmaceuticals, Macclesfield, UK) was administered as a supplement anesthesia throughout the procedure. Plasma samples were obtained in each phase for propofol assay, respectively. Performance parameters for the Diprifusor^® system in each phase, the percentage median performance error (MDPE), the percentage median absolute performance error (MDAPE), and the percentage median absolute constancy error (MDACE) were evaluated. Results: In all patients, measured plasma propofol concentrations were several times higher than Diprifusor^® values in each phase during the procedure. In nine patients, propofol concentrations in the anhepatic phase were higher than those in the paleohepatic or neohepatic phase (P < 0.05). There were no significant differences between the paleohepatic and neohepatic phases. Interindividual variation of the plasma propofol concentrations was significant (P < 0.05). Percentage median performance error of Diprifusor^® in each phase, as well as MDAPE, was large (>300%) and was significantly higher in the anhepatic phase (P < 0.01), whereas MDACE was relatively small and there was no significant difference between phases. Conclusions: Models used by Diprifusor^® are not suitable for liver transplantation patients. A further study should be performed in order to determine all pharmacokinetic parameters of propofol in these patients.     

Comparison of a propofol target-controlled infusion and inhalational sevoflurane for fibreoptic intubation under spontaneous ventilation

BACKGROUND: A propofol target-controlled infusion (TCI) is often proposed for the management of difficult airway intubation and fibreoptic intubation under anaesthesia and spontaneous ventilation. No data are available about sevoflurane. The aim of the present study was to compare propofol and sevoflurane as hypnotics during fibreoptic intubation under spontaneous ventilation. METHODS: After regional ethical committee approval, 52 ASA I-II patients without any predictors for difficult intubation gave their informed consent. They were randomly assigned to one of two groups. After 3 min of pre-oxygenation, patients received either propofol with a plasmatic target concentration of 4 mg/l (group P; n= 26) or sevoflurane 4% with tidal volume ventilation (group S; n= 26). After 2 min, propofol was increased by 1 mg/l and sevoflurane was increased by 1% every 2 min until there was no reaction during mandible translation. This concentration was maintained for 4 min before starting nasotracheal fibrescopy for intubation. During both induction and fibrescopy, pulse oximetry, bispectral index (BIS), heart rate, and arterial blood pressure were monitored. Quality of intubation and operator satisfaction were evaluated. Data were compared using Student's t-test, Mann-Withney U-test or chi-square test. A P-value < 0.05% was considered to be significant. RESULTS: During induction, no difference in pulse oximetry, BIS values at the end of induction, or duration of induction were noticed. Five episodes of desaturation under 90% occurred during fibreoptic intubation in group P compared with none in group S. CONCLUSION: Sevoflurane provides good fibreoptic intubation conditions to spontaneously breathing patients without any hypoxemic episodes such as those observed with propofol.     

Unilateral pulmonary fibrosis following ipsilateral single-lung ventilation and anesthesia]

We experienced a rare case of unilateral pulmonary fibrosis following ipsilateral single-lung ventilation and anesthesia. A 75-year-old man with a 1-pack a day smoking history for 50 years was scheduled for right upper and middle lobectomy for lung cancer. The trachea and left bronchus were intubated with a 37-Fr double-lumen endobronchial tube, and anesthesia was maintained with oxygen, nitrous oxide, isoflurane, and epidural lidocaine. Left single-lung ventilation was maintained for 3.5 hours with FIO2 at 0.8-1.0, vital capacity at 10 ml.kg-1, and peak inspiratory pressure at 25 cmH2O. On postoperative day 55, reticular nodular density in chest roentogenography appeared only in the left lung while right lung showed pleural fluid and pneumonia. On postoperative day 105, a high-resolution computed tomographic scan revealed honeycomb pattern in the left lung and organized pneumonia in the right lung. The patient died from respiratory failure on postoperative day 155, and autopsy was not performed. Although the causative mechanisms of unilateral pulmonary fibrosis in this case was unclear, the patient had not been exposed to any drugs and inhalation agents known to induce pulmonary fibrosis. We speculate that high oxygen concentration, high peak inspiratory pressure, and overdistension of the left lung during the left single-lung ventilation and anesthesia were likely major initiating and contributing factors.     

Effects of sevoflurane and propofol on pulmonary inflammatory responses during lung resection

Purpose  

Pulmonary inflammatory reactions are affected by one-lung ventilation (OLV) and anesthetic agents. However, the effects of anesthetic agents on pulmonary inflammatory reactions may vary. Our previous investigations suggested that inflammatory reactions were more pronounced in the dependent lung during lung resection under general anesthesia with propofol and remifentanil. Therefore, in the present study we attempted to determine the difference in pulmonary inflammatory reaction using either sevoflurane or propofol in both dependent and nondependent lungs during OLV.     

Effects of propofol vs sevoflurane on arterial oxygenation during one-lung ventilation

Background: The inhibitory effect of anaesthetic agents on hypoxic pulmonaryvasoconstriction may depend upon their dose, especially whenusing a volatile agent. The aim of this randomized open studywas to compare the effects of sevoflurane and propofol, as primaryanaesthetic agents, on oxygenation during one-lung ventilation(OLV), with their administration being adjusted to maintainbispectral index (BIS) values between 40 and 60. Methods: Eighty patients scheduled for a lobectomy, receiving an epiduralmixture of ropivacaine and sufentanil, were randomly assignedto Group S (maintenance with sevoflurane) or Group P (maintenancewith propofol). After placement of a double-lumen tube, thelungs were ventilated at an inspiratory fraction of oxygen of1.0, a tidal volume of 6 ml kg^–1, and 12 bpm. Arterialblood gas samples were taken as follows: during two-lung ventilationbefore OLV, and during the first 40 min of OLV. Results: Fifteen patients were excluded (incorrect placement of the tubeor BIS outside the desired range). The two groups were comparablein terms of demographic variables, haemodynamic, and BIS levelsduring the operation. Four patients in each group had a Sp_O2<90%.Mean of the lowest Pa_O2 was 16.3 (7.5) kPa in Group S and 17.7(9.3) kPa in Group P (ns). Conclusions: Sevoflurane and propofol had similar effect on Pa_O2 during OLVwhen their administration is titrated to maintain BIS between40 and 60.     

The single-connector technique for initial placement of double-lumen tubes

Due to the presence of major lung or extra-pulmonary pathology, which may be unilateral or bilateral, the initial placement of a double-lumen tube is not always straightforward. Although fibreoptic bronchoscopy is often used to confirm "correct" placement, a "blind" technique is frequently used for the initial insertion. The currently widely taught blind technique involves tracheal cuff inflation and ventilation of both lungs as a first manoeuvre, with a subsequent assessment of single-lung ventilation by clamping off in turn, the two limbs of the double-lumen tube double-connector: An alternative approach involves the bronchial cuff being inflated first, and then using a single-connector to transfer ventilation from one lung to the other. In this paper this technique is described and compared to the more traditional method. On a purely "number of steps" basis, the single-connector approach has several advantages. Furthermore, use of a technique that involves bronchial cuff inflation and single-lung ventilation as a first manoeuvre may reduce the risk of a temporarily malplaced double-lumen tube creating a potentially harmful ball-valve effect in a partially obstructed lobe or lung.     

Plasma propofol concentration and EEG burst suppression ratio during normothermic cardiopulmonary bypass

Background. During cardiopulmonary bypass (CPB), several factorsaffect drug disposition and action. This topic has not beenstudied extensively during normothermic CPB. In this study,we related propofol dose to plasma propofol concentration andburst suppression of the EEG during normothermic bypass. Methods. After institutional approval and informed consent,45 patients having cardiac surgery were assigned randomly toreceive propofol infusions at 4 (Group A), 5 (Group B) and 6(Group C) mg kg^–1 h^–1 during normothermic CPB. Inall patients, small to moderate doses of fentanyl were alsoadministered. Plasma propofol concentration and burst suppressionratio (BSR) were measured at the following times: (1) 10 minbefore CPB, (2) 10 min after the start of CPB, (3) 30 min afterthe start of the CPB, (4) just after aortic declamping, and(5) 60 min after CPB. Results. At baseline, plasma propofol concentrations were similaramong the three groups. After the start of CPB, the concentrationsof propofol decreased significantly by 41, 35, and 30% of controlvalues in Groups A, B, and C, respectively. In Group A, theconcentration of propofol during CPB remained unchanged at lessthan the concentration before bypass. In Groups B and C, plasmapropofol concentrations gradually increased during CPB to thepre-bypass concentrations. In Group A, BSR values did not changesignificantly during CPB. In Groups B and C, BSR values graduallyincreased and became significantly greater than baseline values.No patient reported intraoperative awareness. Conclusion. The pharmacokinetics and pharmacodynamics of propofolchange during normothermic CPB. During normothermic CPB, theefficacy of propofol may be enhanced compared with before CPB. Br J Anaesth 2003; 90: 122–6     

The ventilation management during the reconstruction of the tracheo-bronchial tree in adults

The most important point of anesthetic management during the reconstruction of the tracheo-bronchial tree (TBT) is to secure the airway and to maintain adequate ventilation. We experienced 17 cases of reconstruction of the TBT. Various methods of ventilation were achieved; one-lung ventilation, right middle and lower lobes ventilation, and combinations of these. We used double-lumen tubes, single-lumen tubes with or without blocker, spiral tubes, and intravenous catheters. We selected an appropriate ventilation method suitable for the diverse operative modes and achieved satisfactory managements during operation.(Ogawa T, Murayama T, Shingu K, et al.: the ventilation management during the reconstruction of the tracheo-bronchial tree in adults. J Anesth 4: 9–19, 1990)