Reduction in mouth opening with semi-rigid cervical collars

Background. Reduced mouth opening may be a major contributingfactor to the deterioration in the view obtained at laryngoscopywhen a semi-rigid cervical collar is in place. We set out toassess the degree to which mouth opening is restricted by acervical collar. Methods. We measured maximal inter-incisor distance in 52 volunteers.It was measured again after application of each of three appropriatelysized semi-rigid cervical collars (Stifneck, Miami J, and Philadelphia). Results. Inter-incisor distance was significantly reduced bythe application of a cervical collar [No collar 41 (7) mm–mean(SD); Stifneck 26 (8) P<0.0001; Miami J 29 (9) P<0.0001;Philadelphia 29 (9) P<0.0001]. There was a wide and unpredictablevariation between subjects in the reduction in mouth openingand a significant proportion had an inter-incisor distance of20 mm or less (Stifneck, 25%; Miami J, 21%; Philadelphia, 21%). Conclusions. Application of a semi-rigid cervical collar cansignificantly reduce mouth opening. This could hinder definitiveairway placement. Our results support removing the anteriorportion of the collar before attempts at tracheal intubation.      

Cardiovascular changes with the laryngeal mask airway in cardiac anaesthesia

Background. The laryngeal mask airway (LMA) causes fewer haemodynamicchanges, particularly in mean arterial pressure (MAP) and heartrate (HR), than tracheal intubation using either laryngoscopyor the intubating LMA. There are no data for patients with coronaryartery disease. Method. We studied 27 patients having coronary artery bypassgrafting, prospectively randomized to be managed with eitherthe LMA or tracheal intubation using either laryngoscopy orthe ILMA. We used invasive monitoring to compare the haemodynamiceffects in each group during induction and emergence from anaesthesia. Results. Both methods of intubation caused an increase in MAPcompared with the LMA (P<0.05). Mixed venous oxygen saturationincreased in the intubated patients but not with the LMA (P<0.05).HR did not change at induction in the LMA group. Changes atextubation were similar in all groups but cardiac index waslower in the LMA group (P<0.05). Conclusion. The LMA allows airway management without hypertensionand tachycardia and should be considered when anaesthetizingpatients with coronary disease. Br J Anaesth 2004; 92: 885–7     

Comparison of two induction regimens using or not using muscle relaxant: impact on postoperative upper airway discomfort

Background: Muscle relaxants facilitate tracheal intubation, but they areoften not used for short peripheral surgical procedures. Theconsequences of this practice on the upper airway are stilla matter of controversy. We therefore compared the incidenceof post-intubation symptoms in a randomized study comparingpatients intubated with or without the use of a muscle relaxant. Methods: A total of 300 adult patients requiring tracheal intubationfor scheduled peripheral surgery were randomly assigned in adouble-blind study to an anaesthetic protocol that either includedor did not include a muscle relaxant (rocuronium). The primaryend-point was the rate of post-intubation symptoms 2 and 24h after extubation. The secondary end-points were the intubationconditions score (Copenhagen Consensus Conference), the rateof difficult intubations (Intubation Difficulty Scale), andthe incidence of adverse haemodynamic events. Results: Post-intubation symptoms were more frequent in patients intubatedwithout the use of a muscle relaxant, whether 2 h (57% vs 43%of patients; P < 0.05) or 24 h (38% vs 26% of patients; P< 0.05) after extubation. Intubation conditions were betterwhen the muscle relaxant was used. In patients intubated withouta muscle relaxant, difficult intubation was more common (12%vs 1%; P < 0.05), as were arterial hypotension or bradycardiarequiring treatment (12% vs 3% of patients; P < 0.05). Conclusions: The use of a muscle relaxant for tracheal intubation diminishesthe incidence of adverse postoperative upper airway symptoms,results in better tracheal intubation conditions, and reducesthe rate of adverse haemodynamic events.     

Gabapentin attenuates the pressor response to direct laryngoscopy and tracheal intubation

Background. Laryngoscopy and tracheal intubation increase bloodpressure and heart rate (HR). The aim of the present study wasto investigate the effect of gabapentin when given before operationon the haemodynamic responses to laryngoscopy and intubation. Methods. Forty-six patients undergoing abdominal hysterectomyfor benign disease were randomly allocated to receive gabapentin1600 mg or placebo capsules at 6 hourly intervals starting theday (noon) before surgery. Anaesthesia was induced with propofoland cis-atracurium. Systolic, diastolic arterial blood pressures(SAP, DAP) and heart rate (HR) were recorded before and afterthe anaesthetic and 0, 1, 3, 5 and 10 min after tracheal intubation. Results. SAP was significantly lower in the gabapentin vs thecontrol group 0, 1, 3, 5 and 10 min after intubation [128 (27)vs 165 (41), P=0.001, 121 (14) vs 148 (29), P=0.0001, 115 (13)vs 134 (24), P=0.002, 111 (12) vs 126 (19), P=0.004 and 108(12) vs 124 (17), P=0.001 respectively]. DAP also was lowerin the gabapentin group 0, 1, 3, and 10 min after intubation[81 (18) vs 104 (19), P=0.0001, 77 (9) vs 91 (16), P=0.001,71 (10) vs 84 (13), P=0.001 and 67 (10) vs 79 (12), P=0.004].HR did not differ between the two groups at any time [82 (11)vs 83 (15), 79 (10) vs 80 (12), 86 (17) vs 92 (10), 82 (11)vs 88 (10), 81 (12) vs 81 (11), 77 (13) vs 79 (13), and 75 (15)vs 78 (12)]. Conclusion. Gabapentin, under the present study design attenuatesthe pressor response but not the tachycardia associated withlaryngoscopy and tracheal intubation.     

Randomized, controlled trial of the double setup tracheal tube during fibreoptic orotracheal intubation under general anaesthesia

Background. Impingement of the tracheal tube (ETT) on upperairway structures during railroading over the fibreoptic bronchoscope(FOB) occurs commonly. Potential complications of impingementinclude prolonged intubation time, leading to arterial desaturation,failed intubation and laryngeal trauma. The objective of thisrandomized, controlled trial was to assess the effect of thedouble setup ETT (a paediatric ETT is placed inside an adultETT) on the incidence of impingement during orotracheal fibreopticintubation. Method. Two hundred patients were randomized to have a singleETT or double setup ETT. After induction of anaesthesia, fibreopticorotracheal intubation was performed. The degree of impingementof the ETT during advancement over the FOB was assessed usinga standardized scoring system based on the manoeuvres requiredto overcome the impingement. Results. The incidence of impingement was lower using the doublesetup ETT compared with the single ETT (18 vs 93%, P<0.001).The double setup ETT also reduced the incidence of impingementrequiring more than a simple 90° counterclockwise rotationto achieve intubation (3 vs 14%, P=0.01) and reduced the medianintubation time (31 vs 35 s, P=0.046). Conclusions. The double setup ETT is effective in reducing ETTimpingement and in reducing intubation time. We did not findan association between ETT impingement and arterial desaturation. Br J Anaesth 2004; 92: 536–40     

Comparative efficacy and safety of remifentanil and fentanyl in 'fast track' coronary artery bypass graft surgery: a randomized, double-blind study

This multi-centre, parallel group, randomized, double-blindstudy compared the efficacy and safety of high-dose remifentaniladministered by continuous infusion with an intermittent bolusfentanyl regimen, when given in combination with propofol forgeneral anaesthesia in 321 patients undergoing elective coronaryartery bypass graft surgery. A significantly lower proportionof the patients who received remifentanil had responses to maximalsternal spread (the primary efficacy endpoint) compared withthose who received fentanyl (11% vs 52%; P<0.001). More patientswho received remifentanil responded to tracheal intubation comparedwith those who received fentanyl (24% vs 9%; P<0.001). However,fewer patients who received remifentanil responded to sternalskin incision (11% vs 36%; P<0.001) and sternotomy (14% vs60%; P <0.001). Median time to extubation was longer in thesubjects who received remifentanil than for those who receivedfentanyl (5.1 vs 4.2 h; P=0.006). There were no statisticallysignificant differences between the two groups in the timesfor transfer from intensive care unit or hospital dischargebut time to extubation was significantly longer in the remifentanilgroup. Overall, the incidence of adverse events was similarbut greater in the remifentanil group with respect to shivering(P<0.049) and hypertension (P<0.001). Significantly moredrug-related adverse events were reported in the remifentanilgroup (P=0.016) There were no drug-related adverse cardiac outcomesand no deaths from cardiac causes before hospital dischargein either treatment group. Br J Anaesth 2001; 87: 718–26     

Videolaryngoscopy vs. flexible fibrescopy for tracheal intubation in patients with cervical spine immobilisation: a randomised controlled trial

In patients with cervical spine immobilisation, tracheal intubation devices other than a direct laryngoscope are frequently used to facilitate tracheal intubation and avoid related complications. In this randomised controlled trial, we compared videolaryngoscopic and fibrescopic tracheal intubation in patients with a cervical collar. Tracheal intubation was performed using either a videolaryngoscope with a non-channelled Macintosh blade (n = 166) or a flexible fibrescope (n = 164) in patients having elective cervical spine surgery whose neck was immobilised with a cervical collar to simulate a difficult airway. The primary outcome was the first attempt success rate of tracheal intubation. Secondary outcomes were the overall success rate of tracheal intubation; time to tracheal intubation; use of additional airway manoeuvres; and incidence and severity of tracheal intubation-related airway complications. First attempt success rate was higher in the videolaryngoscope group than in the fibrescope group (164/166 (98.8%) vs. 149/164 (90.9%), p = 0.003). Tracheal intubation was successful within three attempts in all patients. Median (IQR [range]) time to tracheal intubation was shorter (50.0 (41.0–72.0 [25.0–170.0]) s vs. 81.0 (65.0–107.0 [24.0–178.0]) s, p < 0.001) and additional airway manoeuvres were less frequent (30/166 (18.1%) vs. 91/164 (55.5%), p < 0.001) in the videolaryngoscope group compared with the fibrescope group. The incidence and severity of intubation-related airway complications were not different between the two groups. When performing tracheal intubation in patients with a cervical collar, videolaryngoscopy with a non-channelled Macintosh blade was superior to flexible fibrescopy.     

Bispectral index changes following etomidate induction of general anaesthesia and orotracheal intubation

Background. Etomidate-associated hypnosis has only been studiedusing standard clinical criteria and raw EEG variables. We conducteda BIS-based investigation of etomidate induction of generalanaesthesia. Methods. Thirty hydroxyzine-premedicated ASA I patients wererandomly allocated to receive etomidate 0.2, 0.3, or 0.4 mgkg^–1 intravenously over 30 s. The BIS was continuouslyrecorded. A tourniquet was placed on a lower limb to recordpurposeful movements and myoclonia. Tracheal intubation wasfacilitated using rocuronium 0.6 mg kg^–1 when the BISvalue was 50. The times to disappearance of the eyelash reflex,to a decrease in the BIS to 50, and to tracheal intubation werecompared. The BIS values 30 s following tracheal intubation,and mean arterial pressure (MAP) and heart rate (HR) at alltime points were also recorded. Results. The BIS value decreased to 50 for tracheal intubationwith no purposeful movement in all but one patient in the 0.2mg kg^–1 group. There was no difference between the etomidategroups (0.2, 0.3, and 0.4 mg kg^–1) in regards to timeto loss of the eyelash reflex (103 (67), 65 (34), 116 (86) s,P=0.2), or to a decrease in BIS to 50 (135 (81), 82 (36), 150(84) s, P=0.1). Also, the BIS value 30 s after intubation (41(10), 37 (4), 37 (4), P=0.4), and plasma etomidate concentrations(161 [29–998], 308 [111–730], 310 [90–869]ng ml^–1, P=0.2) did not differ between groups. The timeto loss of the eyelash reflex was 12–140 s shorter thanthe time to a decrease in BIS to 50 in three patients in eachgroup who received etomidate 0.2 and 0.4 mg kg^–1, andin four patients who received 0.3 mg kg^–1. No awarenesswas recorded. MAP and HR increases following tracheal intubationwere comparable between groups. Conclusions. Etomidate induction doses do not predict the timefor BIS to decrease to 50 as this variable varies markedly followingthree etomidate dose regimen. Br J Anaesth 2003; 91: 341–6     

Tight control of prehospital ventilation by capnography in major trauma victims

Background. Tracheal intubation combined with controlled ventilationof the lungs is an important part of the prehospital managementof major trauma victims, but gauging the adequacy of ventilationremains a major problem. Methods. Ninety-seven major trauma victims who underwent trachealintubation in the field and controlled ventilation of the lungsduring prehospital treatment by a Helicopter Emergency MedicalService were assigned randomly to one of two groups: (1) monitorgroup (n=57) and (2) monitor-blind group (n=40), according towhether the anaesthetist could or could not see an attachedcapnograph screen. In the monitor-blind group ventilation wasset by using a tidal-volume of 10 ml kg^–1 estimated bodyweight and an age-appropriate ventilatory frequency. In themonitor group, ventilation was adjusted to achieve target end-tidalcarbon dioxide values determined by the ‘physiologicalstate’ of the trauma victim. Arterial blood gases weremeasured upon hospital admission while maintaining the ventilationinitiated in the field and the Pa_CO2 value obtained was usedas the determinant of the adequacy of prehospital ventilation. Results. The incidence of ‘normoventilation’ wassignificantly higher (63.2 vs 20%; P<0.0001) and the incidenceof ‘hypoventilation’ upon hospital admission wassignificantly lower (5.3 vs 37.5%; P<0.0001) in the monitorgroup; patients with severe head and chest trauma and haemodynamicallyunstable patients and those with a high injury severity scorewere significantly more likely to be ‘normoventilated’upon hospital admission in the monitor group than in the monitor-blindgroup. Conclusions. The data support the routine use of prehospitalcapnographic monitoring using target end-tidal carbon dioxidevalues adapted to the physiological state of the patient inmajor trauma victims requiring tracheal intubation in the field. Br J Anaesth 2003; 90: 327–32     

Effects of remifentanil and alfentanil on the cardiovascular responses to induction of anaesthesia and tracheal intubation in the elderly

Background. We compared the effects of remifentanil and alfentanilon arterial pressure and heart rate at induction of anaesthesiaand tracheal intubation in 40 ASA I–III patients agedgreater than 65 yr, in a randomized double-blind study. Methods. Patients received either remifentanil 0.5 µgkg^–1 over 30 s, followed by an infusion of 0.1 µgkg min^–1 (group R) or alfentanil 10 µg kg^–1over 30 s, followed by an infusion of saline (group A). Anaesthesiawas then induced with propofol, rocuronium, and 1% isofluranewith 66% nitrous oxide in oxygen. Results. Systolic arterial pressure (SAP) and mean arterialpressure (MAP) decreased after the induction of anaesthesia(P<0.05) and increased for 3 min after intubation in bothgroups (P<0.05), but remained below baseline values throughout.Heart rate remained stable after induction of anaesthesia butincreased significantly from baseline after intubation for 1and 4 min in groups R and A, respectively (P<0.05). Therewere no significant between-group differences in SAP, MAP, andheart rate. Diastolic pressure was significantly higher in groupA than group R at 4 and 5 min after intubation (P<0.05).Hypotension (SAP <100 mm Hg) occurred in four patients ingroup R and three patients in group A. Conclusions. Remifentanil and alfentanil similarly attenuatethe pressor response to laryngoscopy and intubation, but theincidence of hypotension confirms that both drugs should beused with caution in elderly patients. Br J Anaesth 2002; 88: 430–3     

Cardiovascular changes after the three stages of nasotracheal intubation

Background. Nasotracheal intubation typically comprises threedistinct stages: (i) nasopharyngeal intubation; (ii) directlaryngoscopy to identify the vocal cords; and (iii) the passageof the tracheal tube into the trachea. The aim of this studywas to identify and compare the cardiovascular responses associatedwith each of these stages. Methods. Seventy-five ASA I or II patients, aged 16–65yr, requiring nasotracheal intubation as part of their anaestheticmanagement, received a standardized general anaesthetic andwere allocated randomly to receive either nasopharyngeal intubationor nasopharyngeal intubation plus direct laryngoscopy or fullnasotracheal intubation. Results. There was a significant hypertensive response, comparedwith pre-induction levels, in all three groups. The maximummean (SD) mean arterial pressure in the nasotracheal intubationgroup was 113 (17.1) mm Hg, which was significantly greaterthan that in the nasopharyngeal intubation (97 (13) mm Hg)(P<0.001) and in the nasopharyngeal intubation plus laryngoscopy(103 (10.3) mm Hg) (P=0.007) groups. There was no significantdifference between the nasopharyngeal intubation and nasopharyngealintubation plus laryngoscopy groups (P=0.206). A similar patternwas seen for both systolic and diastolic arterial pressure.Nasotracheal intubation caused a significant increase in maximummean (SD) heart rate, compared with pre-induction values, whereasthe other two groups caused significant falls. The heart ratein the nasotracheal intubation group (92 (16.5) beats min^–1)was significantly greater than in the other two groups (74 (8.6)(P<0.001) and 76 (12) (P<0.001) beats min^–1respectively). There was no significant difference in heartrates between the nasopharyngeal intubation and nasopharyngealintubation plus laryngoscopy groups (P=0.420). Conclusions. Nasopharyngeal intubation causes a significantpressor response. Stimulation of the larynx and trachea by thepassage of the tracheal tube, but not direct laryngoscopy, causesa significant increase in this response. Br J Anaesth 2003; 91: 667–71     

Isocapnic hyperpnoea accelerates recovery from isoflurane anaesthesia

Background. Hyperventilation should speed up elimination ofvolatile anaesthetic agents from the body, but hyperventilationusually results in hypocapnia. We compared recovery from isofluraneanaesthesia in patients allowed to recover with assisted spontaneousventilation (control) and those treated with isocapnic hyperpnoea. Methods. Fourteen patients were studied after approximately1 h of anaesthesia with isoflurane. Control patients were allowedto recover in the routine way. Isocapnic hyperpnoea patientsreceived 2–3 times their intraoperative ventilation usinga system to maintain end tidal PCO₂ at 45–50 mm Hg. Wemeasured time to removal of the airway and rate of change ofbispectral index (BIS) during recovery. Results. With isocapnic hyperpnoea, the time to removal of theairway was markedly less (median and interquartile range valuesof 3.6 (2.7–3.7) vs 12.1 (6.8–17.2) min, P<0.001);mean (SD) BIS slopes during recovery were 11.8 (4.4) vs 4.3(2.7) min^–1 (P<0.01) for isocapnic hyperpnoea and controlgroups, respectively. Isocapnic hyperpnoea was easily appliedin the operating room. Conclusions. Isocapnic hyperpnoea at the end of surgery resultsin shorter and less variable time to removal of the airway afteranaesthesia with isoflurane and nitrous oxide. Br J Anaesth 2003; 91: 787–92     

Esmolol prevents movement and attenuates the BIS response to orotracheal intubation

Background. Beta-adrenergic agonists enhance behavioural andelectroencephalographic arousal reactions. We explored whetheradding esmolol, a short-acting ß₁-adrenoceptor antagonist,to propofol anaesthesia modified the bispectral index (BIS)during induction of anaesthesia and orotracheal intubation. Methods. Fifty patients were randomly allocated, in a double-blindfashion, to receive esmolol 1 mg kg^–1 followed by 250µg kg^–1 min^–1 or saline (control). Esmololor saline was started 6 min after a target-controlled infusion(TCI) of propofol (effect-site concentration 4 µg ml^–1).After loss of consciousness, and before administration of vecuronium0.1 mg kg^–1, a tourniquet was applied to one arm and inflatedto 150 mm Hg greater than systolic pressure. Eleven minutesafter the TCI began, the trachea was intubated; gross movementwithin the first min after orotracheal intubation was recorded.BIS was recorded at 10-s intervals. Mean arterial pressure (MAP)and heart rate were measured non-invasively every min. Results. There were no intergroup differences in BIS, heartrate or MAP before laryngoscopy. BIS increased significantlyafter orotracheal intubation (compared with the pre-laryngoscopyvalues) in the control group only, with a maximum increase of40 (SD 18)% vs 8 (11)% in the esmolol group (P<0.01). Maximumchanges in heart rate [45 (19)% vs 23 (14)%] and MAP [62 (24)%vs 45 (23)%] with orotracheal intubation were also significantlygreater in the control group than in the esmolol group. Morepatients in the control than in the esmolol group moved afterorotracheal intubation (23 vs 12, P<0.01). Conclusion. Esmolol not only attenuated haemodynamic and somaticresponses to laryngoscopy and orotracheal intubation, but alsoprevented BIS arousal reactions in patients anaesthetized withpropofol. Br J Anaesth 2002; 89: 857–62     

Onset/offset characteristics and intubating conditions of rapacuronium: a comparison with rocuronium

We compared onset and offset of action and tracheal intubatingconditions after rapacuronium and rocuronium in 60 patientsin a randomized, assessor-blinded study. Following inductionof anaesthesia with propofol 2.5 mg kg^–1, eitherrapacuronium 1.5 mg kg^–1 (n=30) or rocuronium0.6 mg kg^–1 (n=30) was administered to facilitatetracheal intubation. Anaesthesia was maintained with eithera propofol infusion (100 µg kg^–1 min^–1)or sevoflurane (1% end-tidal) with 66% nitrous oxide (N₂O),n=15 in each subgroup. Neuromuscular monitoring was performedusing an electromyographic (EMG) device (Datex Relaxograph).The lag times (mean 42 (SD 11) s and 44 (16) s), maximumblock (99 (2)% and 98 (3)%) and intubating conditions at 60 s(good-to-excellent in 86% and 84% of patients) were similarfor rapacuronium and rocuronium, respectively. The onset timeof rapacuronium was shorter than rocuronium (87 (20) vs 141(65) s, P<0.001), and the degree of block at 60 swas greater (69 (26) vs 50 (27)%, P<0.05). Twenty-five percent recovery was shorter with rapacuronium than rocuroniumduring propofol (15.0 (3.2) vs 39.1 (14.2) min, P<0.001)and sevoflurane (15.1 (4.2) vs 47.8 (19.0) min, P<0.001)anaesthesia. We conclude that rapacuronium 1.5 mg kg^–1had a more rapid onset, similar intubating conditions, and shorterrecovery times than rocuronium 0.6 mg kg^–1. Br J Anaesth 2000; 85: 246–50     

The intubating laryngeal mask airway does not facilitate tracheal intubation in the presence of a neck collar in simulated trauma

Tracheal intubation must be performed with great care in the multiply injured patient when it must be assumed that the cervical spine may be damaged. Use of conventional direct laryngoscopy usually requires removal of the neck collar and manual in-line stabilization of the head and neck. The intubating laryngeal mask (ILMA) has been designed to facilitate tracheal intubation in the neutral position. We used the ILMA to intubate the trachea in 10 patients wearing a neck collar and with cricoid pressure applied in a simulated trauma scenario. The ILMA was difficult to insert and ventilation proved difficult. In only two patients was intubation successful. These problems were probably caused by the neck collar strap under the chin lifting up and tipping the larynx anteriorly. On the basis of these findings, ILMA use in a subject wearing a neck collar cannot be recommended.      

Postoperative nausea, vomiting, airway morbidity, and analgesic requirements are lower for the ProSeal laryngeal mask airway than the tracheal tube in females undergoing breast and gynaecological surgery

Background: We test the hypothesis that the frequency of postoperative nauseaand vomiting is similar for the ProSeal laryngeal mask airway(LMA) and the tracheal tube. Methods: Two hundred consecutive female patients (ASA I–II, 18–75yr) undergoing routine breast and gynaecological surgery weredivided into two equal-sized groups for airway management withthe ProSeal LMA or tracheal tube. Results: Ventilation was better and airway trauma less frequent for theProSeal LMA. For the ProSeal group, the time spent in the post-anaesthesiacare unit was shorter (69 vs 88 min, P < 0.0001); fewer dosesof tropisetron were required in the post-anaesthesia care unit(P 0.001) and ward (P = 0.004); morphine requirements werelower in the post-anaesthesia care unit (6.0 vs 8.1 mg, P =0.005) and ward (6.1 vs 8.9, P = 0.004); nausea was less frequentat all times (overall: 13% vs 53%, P < 0.0001); vomitingwas less frequent at 2 h (4% vs 18%, P = 0.003) and 24 h (5%vs 19%, P = 0.004); and sore throat was less frequent at alltimes (overall: 12% vs 38%, P < 0.0001). Conclusions: The ProSeal LMA reduced the absolute risk of postoperative nauseaand vomiting by 40% (53–13%). In patients without theneed for morphine, the ProSeal LMA reduced the absolute riskof postoperative nausea and vomiting by 23% (37–14%).We conclude that the frequency of postoperative nausea, vomiting,airway morbidity, and analgesic requirements is lower for theProSeal LMA than the tracheal tube in females undergoing breastand gynaecological surgery.     

Tracheal intubation in patients with rigid collar immobilisation of the cervical spine: a comparison of Airtraq® and LMA CTrach™ devices*

The aim of this study was to evaluate the effectiveness of the Airtraq^® and CTrach? in lean patients with simulated cervical spine injury after application of a rigid cervical collar. Eighty‐six consenting adult patients of ASA physical status 1 or 2, who required elective tracheal intubation were included in this study in a randomised manner. Anaesthesia was induced using 1 μg.kg^?1 fentanyl, 3 mg.kg^?1 propofol and 0.6 mg.kg^?1 rocuronium, following which a rigid cervical collar was applied. Comparison was then made between tracheal intubation techniques using either the AirTraq or CTrach device. The mean (SD) time to see the glottis was shorter with the Airtraq than the CTrach (11.9 (6.8) vs 37.6 (16.7)s, respectively; p < 0.001). The mean (SD) time taken for tracheal intubation was also shorter with the Airtraq than the CTrach (25.6 (13.5) and 66.3 (29.3)s, respectively; p < 0.001). There was less mucosal damage in the Airtraq group (p = 0.008). Our findings demonstrate that use of the Airtraq device shortened the tracheal intubation time and reduced the mucosal damage when compared with the CTrach in patients who require cervical spine immobilisation.     

Comparison of plain and hyperbaric solutions of ropivacaine for spinal anaesthesia

Background. Preliminary work has shown that ropivacaine providesspinal anaesthesia of shorter duration than bupivacaine, andmay be of particular use in the day-case setting. However, thereare few data comparing the actions of plain and hyperbaric solutionsof this drug. Methods. Forty ASA grade I–II patients undergoing electiveperineal surgery under spinal anaesthesia were randomized toreceive 3 ml ropivacaine 5 mg ml^–1, either in plain solutionor with glucose 50 mg ml^–1. The extent and duration ofsensory and motor block, pulse rate, blood pressure, and timeto mobilization were recorded. Results. Two patients (one per group) were withdrawn becauseof total block failure. There were significant differences inmedian time to onset of sensory block at T10 (plain 10 min;hyperbaric 5 min; P<0.01), median maximum extent (plain T8;hyperbaric T4; P<0.05), and median duration of sensory blockat T10 (plain 25 min; hyperbaric 115 min; P<0.001). However,median times to complete regression of both sensory (270 vs240 min; P<0.05) and motor (180 vs 120 min; P<0.001) blockwere longer in the plain group. Patients therefore mobilizedsooner in the hyperbaric group (218 [n=16] vs 286 min [n=17];P<0.01). All the hyperbaric blocks were adequate for surgery,but three patients receiving plain ropivacaine required generalanaesthesia. Conclusion. Addition of glucose 50 mg ml^–1 to ropivacaine5 mg ml^–1 increases the speed of onset, block reliability,duration of useful block for perineal surgery, and speed ofrecovery. Plain solutions are less reliable for surgery abovea dermatomal level of L1.      

Target concentrations of remifentanil with propofol to blunt coughing during intubation, cuff inflation, and tracheal suctioning

Background. The target blood concentrations of propofol andremifentanil, when used in combination, required to blunt thecough response to tracheal intubation, cuff inflation, and trachealsuctioning without neuromuscular blocking agents are not known. Methods. In a randomized prospective study, 81 patients wereenrolled to determine which of three target remifentanil bloodconcentrations was required to blunt coughing during intubation,cuff inflation, and tracheal suctioning. Anaesthesia was achievedwith propofol at a steady effect-site concentration of 3.5 µgml^–1. The target blood remifentanil concentrations were5, 10, or 15 ng ml^–1. These concentrations were maintainedfor 12 min before intubation. Results. There was no cough response to intubation in more than74% of patients and no significant difference in the incidenceof coughing with intubation between the three groups. Significantdifference in coughing, diminishing with increasing remifentaniltarget concentration, was observed with cuff inflation (P=0.04)and tracheal suctioning (P=0.007). Bradycardia and hypotensionwas more frequent with the remifentanil target concentrationof 15 ng ml^–1. Tracheal suctioning resulted in more coughingthan intubation (P=0.01) or cuff inflation (P=0.004). Conclusion. Target remifentanil blood concentrations of 5, 10,and 15 ng ml^–1 associated with a 3.5 µg ml^–1propofol target blood concentration provided good intubatingconditions and absence of cough about 75% of the time. Highertarget remifentanil concentrations were associated with lesscoughing during tracheal tube cuff inflation and tracheal suctioning.     

Role of beta-blockade in anaesthesia and postoperative pain management after hysterectomy

Background. Perioperative use of ß-blockers has beenadvocated as a strategy to prevent cardiac sequelae. This studyevaluated the influence of perioperative esmolol administrationupon anaesthesia and postoperative pain management amongst patientsundergoing hysterectomy. Methods. Ninety-seven ASA I–II patients, undergoing abdominaltotal hysterectomy, were randomly divided into one of two groups.Patients in the Esmolol group received an i.v. loading doseof esmolol 0.5 mg kg^–1 followed by infusion of 0.05 mgkg^–1 min^–1 before anaesthesia induction. The infusionwas documented at the completion of surgery. The Control groupreceived a volume of normal saline. After surgery, all patientswere treated with patient-controlled i.v. analgesia (PCA), whichwas programmed to deliver 1 mg of morphine on demand for 3 consecutivedays. Pain intensity on movement and at rest, sedation score,and side effects were recorded. Results. The two groups were comparable with respect to theircharacteristics. Patients in the esmolol group received significantlylower end-tidal isoflurane concentrations (1.0 (0.3) vs 1.4(0.5)%, respectively; P<0.001) and fentanyl (0.9 (0.2) vs1.2 (0.5) µg kg^–1, respectively; P=0.006) duringanaesthesia. They also showed a reduced heart rate and arterialpressure response to tracheal intubation, skin incision, andtracheal extubation. The Esmolol group consumed less PCA morphinein 3 days (37.3 (8.4) vs 54.7 (11.2) mg, respectively; P=0.005).Pain intensity and medication side effects were similar in thetwo groups. Conclusion. The results suggest that perioperative esmolol administrationduring anaesthesia reduces the intraoperative use of inhalationanaesthetic and fentanyl, decreases haemodynamic responses,and reduced morphine consumption for the first 3 postoperativedays.