***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: One hundred and fifty‐eight unpremedicated patients scheduled for elective surgery were allocated r and omly to receive an unsupplemented induction dose of thiopentone or propofol .  Visualisation of the vocal cords by st and ard laryngoscopy was possible more often after propofol ( p < 0.01 ) . Pharyngeal and laryngeal reactivity was similarity depressed more frequently BACKGROUND To investigate whether the effects of desflurane on inspiratory resistance are similar to those of isoflurane and sevoflurane during 30 min administration at 1 and 1.5 MAC in patients with healthy lungs . METHODS Seventy-one patients undergoing elective surgery were r and omly assigned to receive isoflurane , sevoflurane , or desflurane . Baseline inspiratory resistance was obtained after intubation and establishment of volume control ventilation . Anaesthesia was maintained with desflurane , isoflurane , or sevoflurane at 1 MAC for 30 min followed by 1.5 MAC for another 30 min . Tidal volume , flow , and inspiratory pressures were continuously recorded with a pneumotachograph . Total inspiratory resistance ( R(rs ) ) , minimal resistance ( R(min ) ) , and effective resistance ( D(Rrs ) ) were calculated every 5 min using the end-inspiratory occlusion technique . RESULTS No significant differences of the evaluated parameters ( R(rs ) , R(min ) and D(Rrs ) ) were observed during administration of the three agents at 1 MAC for 30 min . At 1.5 MAC , desflurane caused a maximum increase in R(rs ) by 26 % and in R(min ) by 30 % above baseline , in contrast to isoflurane and sevoflurane which did not display a significant effect on R(rs ) ( + 3.7 % by isoflurane and + 7.6 % by sevoflurane ) and R(min ) ( + 4.7 % by isoflurane and + 9.6 % by sevoflurane ) . All parameters returned to baseline after discontinuation of the volatile agent . CONCLUSIONS In healthy adults , neither sevoflurane nor isoflurane produced bronchodilation at 1 and 1.5 MAC . Desflurane did not affect respiratory resistance at 1 MAC , but at 1.5 MAC caused significant increase in both total and airway resistance with return to near baseline values after discontinuation of the agent Background Smoking is considered to be a risk factor for patients undergoing surgery and anesthesia , but it is unclear whether this is applicable to patients undergoing ambulatory surgery . The aim of this study was to determine the risk of respiratory complications and wound infection among smokers . Methods The authors studied a r and om selection of 489 adult patients undergoing ambulatory surgery .  Smoking status was determined by self-report and confirmed with end-expired carbon monoxide analysis . The risk of respiratory complications ( i.e. , desaturation , cough , laryngospasm , bronchospasm , breath-holding , or apnea ) and wound infection ( i.e. , wound redness or discharge ± positive microbial culture , requiring antibiotic therapy ) in smokers versus nonsmokers was ascertained . Odds ratios were estimated from multivariable logistic regression and adjusted for age , gender , body mass index , partner 's smoking status , domiciliary smoking exposure , and extent and duration of surgery . Results Most smokers continued to smoke up until the day of surgery . Smokers had a higher rate of respiratory complications ( 32.8%vs . 25.9 % ; adjusted odds ratio , 1.71 ; 95 % confidence interval , 1.03–2.84;P = 0.038 ) and wound infection ( 3.6%vs . 0.6 % ; odds ratio , 16.3 ; 95 % confidence interval , 1.58–175;P = 0.019 ) . Odds ratios comparing current plus ex-smokers with nonsmokers were of similar magnitude for most of these complications . Conclusions Smoking was associated with an increased risk of respiratory complications and postoperative wound infection in ambulatory surgery patients . These findings warrant increased efforts at promoting smoking avoidance and cessation BACKGROUND The cuffed oropharyngeal airway ( COPA ) is a modified Guedel-type oral airway with a cuff at its distal end . The objectives of this prospect i ve , r and omized study were to compare the COPA and the laryngeal mask airway ( LMA ) in terms of propofol requirement with and without fentanyl pretreatment for smooth insertions . METHODS Seventy-five patients undergoing general anaesthesia were r and omly assigned to either a COPA ( n=38 ) or LMA ( n=37 ) group for airway management , and each group was further r and omized to a saline-propofol or fentanyl-propofol group for anaesthesia induction . The saline-propofol group received i.v . saline and the fentanyl-propofol group received i.v . fentanyl 1 micro g kg(-1 ) followed 30 s later by i.v . propofol . Insertion of the device was attempted 90 s after propofol administration without the use of neuromuscular blocking agents or other adjuvants , and the responses of ' movement ' or ' no movement ' were judged by three observers blinded to the drug dose . Each dose of propofol at which insertion was attempted was predetermined by modification of Dixon 's up- and -down method with 0.5 mg kg(-1 ) as the step size , and 2 mg kg(-1 ) as an initial dose . RESULTS Without fentanyl pretreatment , propofol requirement [ mean ( SD ) , 95 % CI ] for COPA placement [ 2.17 ( 0.38 ) , 1.77 - 2.56 mg kg(-1 ) ] was significantly less than for LMA insertion [ 3.42 ( 0.26 ) , 3.15 - 3.69 mg kg(-1 ) , P<0.001 ] . In contrast , propofol requirements after fentanyl were comparable between the COPA and LMA groups [ 1.50 ( 0.42 ) , 1.06 - 1.94 and 1.42 ( 0.26 ) , 1.15 - 1.69 mg kg(-1 ) , respectively ] , but were less than for the placebo group with both devices ( P<0.05 ) . Haemodynamic changes and duration of apnoea were similar with both devices irrespective of fentanyl pretreatment . CONCLUSIONS Insertion of the COPA can be accomplished with a smaller bolus dose of propofol compared with the LMA , but propofol requirements are similar with both devices after a small dose of fentanyl The effect of breathing 0.1 minimum alveolar concentrations ( MAC ) of desflurane or isoflurane for three minutes on the incidence of adverse airway events on a subsequent breath of 2 MAC was investigated . Twenty‐five volunteers known to develop an adverse airway event to desflurane or isoflurane took part in the study . Each volunteer was exposed to isoflurane and desflurane at least 24 h apart . Volunteers were assessed for adverse airway events while breathing 2 MAC inhalational anaesthetic following breathing 100 % O2 for 3 min . This was repeated with 0.1 MAC inhalational anaesthetic in oxygen instead of 100 % O2 . Adverse airway events decreased from 88 % to 40 % when tests were conducted with desflurane ( p = 0.002 ) . With isoflurane , the reduction from 60 % to 52 % was not statistically significant ( p = 0.774 ) . Breathing low concentrations of desflurane decreases the incidence of adverse airway events on subsequent inhalation of higher concentration of desflurane Desflurane ( formerly I-653 ) is a new inhalaticnal anesthetic with a promising pharmacokinetic profile that includes low solubility in blood and tissue , including fat . Since its lipid solubility is less than that of other volatile agents , it may have lower potency . Low solubility would be expected to increase the rate at which alveolar concentration approaches inspired concentration during induction as well as to increase the rate of elimination of desflurane from blood at emergence . We determined the minimum alveolar concentration ( MAC ) of desflurane in 44 unpremedicated ASA physical status 1 or 2 patients undergoing elective surgery . We prospect ively studied four patient groups distinguished by age and anesthetic regimen : 18 - 30 versus 31 - 65 yr and desflurane in 60 % N2O/40 % O2 versus desflurane in O2 .  Anesthesia was induced with desflurane or desflurane in 60 % N2O/40 % O2 .  MAC was determined by a modification of Dixon 's up- and -down method with increments of 0.5 % desflurane . The MAC of desflurane in O2 was 7.25 + /- 0.0 ( mean + /- SD ) in the 18 - 30-yr age group , and 6.0 + /- 0.29 in the 31 - 65-yr group ; the addition of 60 % N2O reduced the MAC to 4.0 + /- 0.29 and 2.83 + /- 0.58 , respectively . The median time from discontinuation of desflurane to an appropriate response to comm and s was 5.25 min . Desflurane appears to be a mild airway irritant but was well tolerated by all patients Purpose To compare patient outcomes for positive pressure ventilation ( PPV ) and spontaneous ventilation ( SV ) in non-paralysed patients with the LMA using either isoflurane or sevoflurane anaesthesia . Methods : One hundred and sixty four adult patients were studied . Anaesthesia was with fentanyl/propofol and N2O 66 % in O2 with 0.75 MAC isoflurane or sevoflurane and either PPV or SV Positive pressure ventilation was with tidal volumes of 6–8 ml·kg−1 . Peak airway pressures were < 15 cm H2O . Patients were evaluated for airway problems , cardiorespiratory effects , and anaesthesia emergence times . Results There were no failed episodes of PPV or SV Gastric insufflation was not detected by epigastric auscultation . Airway problems and cardiovascular effects were similar among groups . During maintenance : SpO2 was greater in the PPV group than in the SV group ( 98.4 vs 97%,P < 0.001 ) ; also , ( PETCO2 ) ( 34 vs 43 mmHg ) and the respiratory rate ( RR ) ( 15 vs 19 min−1 ) were higher and the minute ventilation(MV ) ( 5.7 vs 7.2 L ) were lower in the SV groups ( P < 0.0001 ) . Shorter times to LMA removal and orientation were observed in the sevoflurane groups ( P < 0.0001 ) . Conclusions Patient outcome is similar for SV and PPV in non-paralysed adult patients with the LMA . Isoflurane and sevoflurane at 0.75 MAC provide suitable conditions for maintenance and emergence , but emergence is more rapid with sevoflurane . RésuméObjectifComparer l’évolution du patient lors de la ventilation en pression positive ( VPP ) et de la ventilation spontanée ( VS ) chez des patients non curarisés utilisant l’anesthésie avec ML sous isoflurane ou sévoflurane . MéthodesOn a étudié cent soixante-quatre patients adultes . Lanesthésie s’est faite avec le fentanyl et le propofol et N2O à 66 % dans O2 avec une CAM d’isoflurane ou de sévoflurane à 0,75 et la VPP ou la VS . La ventilation en pression positive était maintenue à des volumes courants de 6–8 ml·kg−1 . Les pressions de pointe ventilatoires étaient < 15 cm H2O . On a évalué chez les patients les problèmes des voies aériennes , les effets cardiorespiratoires et les temps de réveil . RésultatsIl n’y a eu aucun échec de la VPP ou de la VS . On n’a pas détecté d’insufflation gastrique à l’auscultation épigastrique . Les problèmes des voies aériennes et les effets cardiovasculaires étaient semblables dans les deux groupes . Pendant le maintien de l’anesthésie , la SpO2 était plus élevée dans le groupe sous VPP que dans le groupe en VS ( 98,4 vs 97 % , P < 0,001 ) ; on a aussi noté que la ( PETCO2 ) ( 34 vs 43 mmHg ) et la fréquence respiratoire ( FR ) ( 15 vs 19 min−1 ) étaient plus élevées et que la ventilation minute ( VM ) ( 5,7 vs 7,2 L ) était plus basse dans le groupe en VS ( P < 0,0001 ) . On a observé des temps de retrait du ML et de retour à la conscience plus courts dans le groupe qui a reçu du sévoflurane ( P < 0,0001 ) . Conclusion Avec l’utilisation du ML , l’évolution des patients adultes non curarisés est similaire pour la 
    Output:
    
The times of all emergence variables were significantly faster in the desflurane group than in all other groups .
When using an LMA , upper airway adverse reactions in association with desflurane anaesthesia were no different from those noted with sevoflurane , isoflurane or propofol anaesthesia .
Emergence from general anaesthesia with desflurane is significantly faster than all the other anaesthetics .