A randomized controlled trial comparing the cuffed oropharyngeal airway and the laryngeal mask airway in spontaneously breathing anesthetized adults

Intraoperative Laryngeal Mask Airway-Related Hiccup: An Overview

Hiccup is an involuntary contraction of the diaphragm and intercostal muscles resulting in sudden inspiration and closure of the glottis. The presence of hiccup in the perioperative period can be a challenging problem. Sudden movements of the patient from hiccups can interfere preoperative diagnostic procedures, intraoperative hiccup may delay the beginning of surgery, interfere with the surgical process, and affect intraoperative monitoring, and postoperative hiccup may affect would healing and hemodynamic stability. Hiccup can lead to have increased aspiration risk. Hiccup are is an incompletely understood phenomenon with multiple etiologies. Intraoperative hiccup related to laryngeal mask airway placement has been reported, and it presents unique challenges in diagnosis and management. Both pharmacological and non-pharmacological interventions have been utilized with various level of success. All treatment strategies are primarily aimed at interrupting the hiccup reflex arc.

Nasal intubation: A comprehensive review

Nasal intubation technique was first described in 1902 by Kuhn. The others pioneering the nasal intubation techniques were Macewen, Rosenberg, Meltzer and Auer, and Elsberg. It is the most common method used for giving anesthesia in oral surgeries as it provides a good field for surgeons to operate. The anatomy behind nasal intubation is necessary to know as it gives an idea about the pathway of the endotracheal tube and complications encountered during nasotracheal intubation. Various techniques can be used to intubate the patient by nasal route and all of them have their own associated complications which are discussed in this article. Various complications may arise while doing nasotracheal intubation but a thorough knowledge of the anatomy and physics behind the procedure can help reduce such complications and manage appropriately. It is important for an anesthesiologist to be well versed with the basics of nasotracheal intubation and advances in the techniques. A thorough knowledge of the anatomy and the advent of newer devices have abolished the negative effect of blindness of the procedure.

Propofol requirement for insertion of I-gel versus laryngeal mask airway: A comparative dose finding study using Dixon's up-and-down method

Background and Aims:

Propofol is the drug of choice when used as sole anesthetic agent for placement of supraglottic airway devices. We aimed to find and compare the propofol dose required for smooth first attempt insertion of I-gel versus the classic laryngeal mask airway (cLMA) using Dixon's up-and-down method.

Material and Methods:

Prospective randomized controlled trial (n-60) was planned. I-gel or cLMA was inserted 60 s after propofol injection whose dose was calculated based on previous patients response as per Dixon's up-and-down method. Propofol requirements for successful placement of devices was noted and compared. Difference between the groups was measured by ANOVA. A P < 0.05 was considered as statistically significant.

Results:

Significantly lower (P < 0.001) propofol dose was required for I-gel (2.02 ± 0.26 mg/kg) insertion than cLMA (2.70 ± 0.28 mg/kg).

Conclusions:

I-gel requires significantly lower dose of propofol for insertion when compared to cLMA.

Cuffed oropharyngeal airway for difficult airway management

Difficulties with airway management are often caused by anatomic abnormalities due to previous oral surgery. We performed general anesthesia for a patient who had undergone several operations such as hemisection of the mandible and reconstructive surgery with a deltopectoralis flap, resulting in severe maxillofacial deformation. This made it impossible to ventilate with a face mask and to intubate in the normal way. An attempt at oral awake intubation using fiberoptic bronchoscopy was unsuccessful because of severe anatomical abnormality of the neck. We therefore decided to perform retrograde intubation and selected the cuffed oropharyngeal airway (COPA) for airway management. We inserted the COPA, not through the patient's mouth but through the abnormal oropharyngeal space. Retrograde nasal intubation was accomplished with controlled ventilation through the COPA, which proved to be very useful for this difficult airway management during tracheal intubation even though the method was unusual.

A pilot study to examine the effect of the Tulip oropharyngeal airway on ventilation immediately after mask ventilation following the induction of anaesthesia

The Tulip airway is an adult, disposable, single-sized oropharyngeal airway, that is connectable to an anaesthetic circuit. After a standardised induction of anaesthesia in 75 patients, the ease of insertion, intracuff pressure and intracuff volume were measured, as were the end-tidal carbon dioxide levels, airway pressures and tidal volumes over three breaths. Successful first-time insertion was achieved in 72 patients (96%, CI 88.8-99.2%) and after two attempts in 74 patients (99%, CI 92.8-100%). There was outright failure only in one patient. In 60 patients (80%, CI 72.2-90.4%), the Tulip airway provided a patent airway without additional manoeuvres, but in 14 patients, jaw thrust or head extension was necessary for airway patency. The main need for these adjuncts appeared to be an initial under-inflation of the cuff. These promising results are consistent with recent manikin studies using this device.

The air-Q(®) intubating laryngeal airway vs the LMA-ProSeal(TM) : a prospective, randomised trial of airway seal pressure

We performed a prospective, open-label, randomised controlled trial comparing the air-Q(®) against the LMA-ProSeal™ in adults undergoing general anaesthesia. One hundred subjects (American Society of Anesthesiologists physical status 1-3) presenting for elective, outpatient surgery were randomly assigned to 52 air-Q(®) and 48 ProSeal devices. The primary study endpoint was airway seal pressure. Oropharyngolaryngeal morbidity was assessed secondarily. Mean (SD) airway seal pressures for the air-Q(®) and ProSeal were 30 (7) cmH (2) O and 30 (6) cmH(2) O, respectively (p = 0.47). Postoperative sore throat was more common with the air-Q(®) (46% vs 38%, p = 0.03) as was pain on swallowing (30% vs 5%, p = 0.01). In conclusion, the air-Q(®) performs well as a primary airway during the maintenance of general anaesthesia with an airway seal pressure similar to that of the ProSeal, but with a higher incidence of postoperative oropharyngolaryngeal complaints.

Advanced trauma life support, 8th edition, the evidence for change

The American College of Surgeons Committee on Trauma's Advanced Trauma Life Support Course is currently taught in 50 countries. The 8th edition has been revised following broad input by the International ATLS subcommittee. Graded levels of evidence were used to evaluate and approve changes to the course content. New materials related to principles of disaster management have been added. ATLS is a common language teaching one safe way of initial trauma assessment and management.

Evaluation of the revised laryngeal tube suction: the laryngeal tube suction II in 100 patients

BACKGROUND

We prospectively assessed the performance of the laryngeal tube suction mark II (LTS II).

METHODS

LTS II was assessed during controlled and spontaneous ventilation during total i.v. anaesthesia. Ventilation adequacy, functional and anatomical positioning and airway seal were evaluated.

RESULTS

One hundred healthy patients (30F:70M) aged 18-85-yr-old were studied. Insertion of the LTS II was successful in 71 at first attempt, in 24 at second attempt and in five at third/fourth attempt. Median insertion time was 15 s (range 5-120 s). Temporary obstruction occurred in six patients. A median of one manipulation per patient was required to establish an airway (range 0-5). During maintenance, temporary airway obstruction occurred in eight patients. Use of the device was abandoned once during insertion, once during maintenance and once because of complications unrelated to the study. The airway was clear in 89 of 97 patients during maintenance and partially obstructed in eight. Median seal pressure was 29.5 (range 15-85) cm H2O. A gastric tube was passed via the posterior channel in 97 of 99 patients. The glottis was visible using a fibrescope passed via the device in 51% of patients. Via the drain tube the upper oesophagus was visible in 22% and this was open in 50%. Blood was visible on the device after removal in 12 patients. After the operation 14 patients reported mild sore throat.

DISCUSSION

The LTS II appears to be an improvement on its predecessor and merits further investigation comparing it with its competitors during use for anaesthesia and emergency airway management.

A randomised comparison of the Portex Softseal laryngeal mask airway with the LMA-Unique during anaesthesia

We have compared the performance of the single use laryngeal airway devices Softseal and LMA-Unique in a randomised comparative trial in anaesthetised healthy patients who did not receive neuromuscular blockade. Primary outcome was success of airway placement. Secondary outcomes included manipulations and complications during use, ease of insertion, airway and fibreoptic assessment of airway positioning, and complications postoperatively. We planned to study 300 patients but interim analysis demonstrated the study should be stopped after 100 patients. During insertion the Softseal required more attempts for successful insertion (p = 0.041), more manipulations (p < 0.0001) and caused more complications (p = 0.048). Failure of placement occurred in five cases with the Softseal and none with the LMA-Unique (p = n/s). Two Softseal needed to be removed during maintenance because of airway obstruction, giving an overall failure rate of seven (p = 0.013). Serial tests of positioning favoured the LMA-Unique (p = 0.012). Ventilation was more successful in the LMA-Unique group but the difference was not significant (p = 0.051). Seal pressure was higher with the Softseal (26.5 vs. 20.5 cmH(2)O, p = 0.005). Fibreoptic view via the devices was not statistically significantly different. During maintenance of anaesthesia more complications arose with the Softseal (p = 0.03). Anaesthetist ratings of ease of insertion and overall usefulness favoured the LMA-Unique (p < 0.0001 and p = 0.024, respectively). After anaesthesia, sore throat occurred more frequently and was more severe in those patients anaesthetised with a Softseal both in recovery (p = 0.015) and at 24 h (p = 0.012). We conclude that the Softseal performs less well and causes more complications than the LMA-Unique.

Nasal versus oral fiberoptic intubation via a cuffed oropharyngeal airway (COPA™) during spontaneous ventilation

STUDY OBJECTIVE

To compare the success rate of nasal versus oral fiberoptic intubation in anesthetized patients breathing spontaneously via the cuffed oropharyngeal airway (COPAtrade mark).

DESIGN

Prospective, randomized, controlled study.

SETTING

Two university-affiliated hospitals.

PATIENTS

Patients scheduled for general or plastic surgery of the torso or extremities.

INTERVENTIONS

Nasal (n=20) and oral (n=20) fiberoptic intubation were performed in patients while breathing spontaneously via the COPA during standardized anesthesia.

MEASUREMENTS

Demographic data, mean arterial pressure, heart rate, end-tidal carbon dioxide (ETCO2), oxygen saturation (SpO2), COPA size, difficult airway predictors, rate of failed ventilation via COPA, and frequency of hypoxemia (SpO2 < 90%) during the procedure, and perioperative untoward events were recorded.

MAIN RESULTS

The background, airway difficulty, vital signs and untoward effects were similar in the two groups. Nasal fiberoptic laryngeal view (scale 1-4) was better than the oral grading (3 [median] vs. 2, respectively; p <0.05). Eighty percent of the nasal intubations were successful compared with 40% of the oral intubations (p <0.05). Nasal intubations were accomplished within 153 +/- 15 SD seconds compared with 236 +/- 22 seconds (p <0.05) for the oral intubations, and less propofol was needed in the nasal intubations during the procedures (240 +/- 27 mg [nasal] vs. 277+/- 39 mg [oral]; p <0.05).

CONCLUSIONS

Nasal fiberoptic laryngoscopy is more successful and easy than the oral approach in anesthetized patients who are breathing spontaneously through the COPA.

Cardiovascular changes after extraglottic airway insertion: A prospective, randomized comparison between the laryngeal mask or the new PAXpress

STUDY OBJECTIVE

To compare hemodynamic responses induced with the new extraglottic airway, PAXpress, and the classic Laryngeal Mask Airway (LMA).

DESIGN

Prospective, randomized study.

SETTING

Anesthesia department of a university teaching hospital.

PATIENTS

70 ASA physical status I and II patients, aged 18 to 65 years, scheduled to receive general anesthesia for extraabdominal procedures of short duration.

INTERVENTIONS

Patients were randomly allocated to receive either a LMA (n = 35) or a PAXpress (n = 35) placement. After midazolam premedication (0.05 mg kg-1) and general anesthesia induction (propofol 2.5 mg kg-1, and fentanyl 1 microg kg-1) the airways were placed according to manufacturer instructions; then general anesthesia was maintained with a 2% sevoflurane concentration and an air/oxygen mixture.

MEASUREMENTS AND MAIN RESULTS

Arterial blood pressure [both systolic (SBP) and diastolic (DBP)] and heart rate (HR) values were recorded immediately before airway placement, immediately after airway placement, then every 1 minute during the first 5 minutes. During the first 5 minutes after airway insertion, both SBP and DBP values were higher with the PAXpress than the LMA (repeated measures analysis of variance:p = 0.02 and p = 0.006, respectively), whereas no differences were reported in HR values. Also, the maximum percentage increase in both SBP and DBP values was larger with PAXpress [+19% (range: -19% to +80%) for SBP and +26% (range: -17% to +96%) for DBP] than the LMA [+9% (range: -30% to +90%) for SBP and +10% (range: -30% to +92%) for DBP] (p = 0.006 and p = 0.001, respectively).

CONCLUSIONS

Although further studies are required to evaluate safety and airway trauma of this new extraglottic airway, placing the PAXpress produces more marked changes in hemodynamic variables as compared with those produced by the LMA.

Use of cuffed oropharyngeal airway (COPA) for awake intracranial surgery

A comprehensive anesthetic plan for managing patients undergoing "awake: intracranial surgery (AICS) must include a means of rescuing the patient if the airway becomes obstructed. Since access to the patient's airway is limited, mask ventilation can be challenging and laryngoscopy and tracheal intubation, impossible. The need exists for an alternative airway device that is easy to insert, would allow controlled ventilation, and would facilitate a smooth emergence with minimal coughing. The cuffed oropharyngeal airway (COPA) was introduced as a supraglottic airway device in spontaneously breathing patients. The authors report their preliminary experience of its use in AICS. The COPA was inserted in 20 patients on 31 occasions. Insertion of the COPA was accomplished easily at the first attempt in all cases irrespective of patient position. Airway maneuvers were required when patients were supine but not lateral. The COPA is a useful device to instrument the airway in patients undergoing AICS using the asleep-awake-asleep technique in the lateral position.

Randomized comparison of the classic Laryngeal Mask Airway TM with the Airway Management Device TM during anaesthesia

BACKGROUND

We compared the modified Airway Management Device (AMD) with the classic Laryngeal Mask Airway (cLMA) in a randomized comparative trial.

METHODS

Primary outcome was success of airway placement. Secondary outcomes included time to achieve an airway, airway manipulations required, complications during use and fibre-optic assessment of airway positioning.

RESULTS

We planned to study 300 patients but interim analysis demonstrated the study should be stopped after 100 patients. The AMD was inserted on the first attempt less frequently than the cLMA (P=0.04). Eight AMDs and one cLMA could not be placed within three attempts (P=0.03). The AMD required more attempts (P=0.03) and more manipulations (P=0.02) and caused more complications (P=0.01) during insertion. During maintenance of anaesthesia, three AMDs and no cLMAs had to be removed as a result of complications. Seal pressure was better with the AMD than with the cLMA (AMD 25 cm H2O, cLMA 20 cm H2O, P=0.001). Efficacy of ventilation was better with the cLMA than with the AMD (P=0.005). On fibre-optic examination, positioning over the larynx was better with the cLMA than with the AMD (P=0.005). Two of 32 attempts to pass an orogastric tube via the AMD were successful. During recovery, two AMDs and no cLMAs required premature removal. Tolerance during emergence, the incidence of blood on the devices and the incidence of postoperative complications were equivalent between devices. Overall failure rate of the AMD was greater than that of the cLMA (P=0.001).

CONCLUSIONS

Successful insertion of the cLMA is more likely than that of the AMD. Insertion of the AMD required more attempts and caused a greater number of complications. Fibre-optic position was poorer than with the cLMA. When an airway is established, the AMD caused a greater number of complications during anaesthesia and failed more frequently than the cLMA. During recovery from anaesthesia, more complications occurred with the AMD. Overall performance of the AMD was poorer than with the classic LMA.

Upper airway patency during ventilation with a new airway device—the glossopalatinal tube

INTRODUCTION

We studied a new rescue breathing device consisting of a mouthcap and a "glossopalatinal" tube reaching between tongue and palate (the "GPT"), with a connector for a bag, ventilator or rescuers mouth. By tilting the connector in a cranial direction, the tongue can be "scooped" out of the hypopharynx. The study was to test the efficacy and the ease of application of the GPT in anaesthetised patients. It was compared with a conventional face mask with and without an oropharyngeal (OP) airway.

METHODS

19 patients (ethics committee approval, informed consent) anaesthetised for elective surgery were ventilated using an anaesthesia circuit and Ventilog (Draeger) through the GPT and via a face mask (Laerdal) with and without an OP tube. Flow and pressures at the airway opening, in the hypopharynx and the trachea were measured, and the resistance was derived. In addition, the relations of the devices to the anatomical structures were visualised by fibrescope, and ease of operation and fit on the face were scored.

RESULTS AND CONCLUSIONS

Inspiratory resistance with the GPT and mask did not differ (1.31+/-0.96 vs. 1.38+/-0.66 kPa s/l at 1 l/s, mean+/-standard deviation (S.D.); reduction of resistance by "scooping" the tongue through angulation of the GPT (to 0.64+/-0.32; P<0.05 vs. GPT without angulation) was equivalent to that by an OP tube used with the mask (to 0.68+/-0.26; P<0.05 vs. mask solo). Pharyngoscopy showed that the effectiveness of the GPT depended on the individual anatomy. The angulating motion caused some fatigue. The GPT is an alternative to established breathing adjuncts; despite not protruding into the pharynx it can enhance airway patency like an OP.

An evaluation of the PA(Xpress) pharyngeal airway - a new single use airway device

The PA(xpress) phayngeal airway (PA(x)) is a new single use airway device that might be used for airway maintenance during anaesthesia or cardiopulmonary resuscitation. We evaluated the performance of the PA(x) in 103 anaesthetised non-paralysed patients undergoing non-emergency anaesthesia. We recorded success of insertion, quality of airway achieved and complications of its use. We were successful in establishing a clear airway on the first attempt on 68 (67%) occasions. We were unable to establish a patent airway in nine (9%) patients. Partial or intermittent airway obstruction occurred during maintenance of anaesthesia in ten (11%) cases but none required removal of the device. Jaw thrust was used to assist insertion in all cases. A mean of 1.37 further manipulations per patient were required to establish an airway and 0.60 per patient were required during maintenance of anaesthesia. In the 94 patients in whom an airway was established, assisted ventilation was excellent in 77 (82%). Leak pressure was 20 cmH2O or above in 58% cases. Intracuff pressure was measured in 55 patients: mean pressure was 68 cmH2O and was above 100 cmH2O in ten (18%) cases. Complications occurred in 38 (37%) patients during insertion, in a further 12 (13%) during maintenance and in eight (9%) during emergence. The device was difficult to insert and associated with a high incidence of trauma: blood was visible on the device after removal in 56 (55%) cases. We conclude that the PA(x) is associated with too high a failure rate and too high an incidence of minor complications for routine airway maintenance.

Controversial issues in ambulatory anesthesia

Many controversies surround ambulatory anesthesia, but this article concentrates on two major areas: monitoring devices and airway management. Being able to monitor the depth of anesthesia has been a long-term goal with the aim of avoiding awareness during surgery. As monitoring devices are developed, they are being used to reduce anesthetic delivery and reduce costs, possibly increasing the risk of awareness. Management of the airway has been revolutionized by the laryngeal mask, and this article reviews some controversial uses. Several other airway devices that have been developed and promoted as suitable alternatives also are evaluated.

The PAxpress is an effective ventilatory device but has an 18% failure rate for flexible lightwand-guided tracheal intubation in anesthetized paralyzed patients

PURPOSE

The PAxpress is a new, single-use, extraglottic airway device. We evaluate: 1) insertion success rates; 2) airway sealing pressure, ventilatory capability and calculated mucosal pressures (in vitro minus in vivo intracuff pressure) at 30-60 mL cuff inflation volume; 3) the feasibility of lightwand-guided tracheal intubation; and 4) the incidence of mucosal trauma.

METHODS

Ninety anesthetized, paralyzed adults were studied. Airway management was by senior anesthesiologists with no prior experience with the PAX, but considerable experience with extraglottic airway devices and the flexible-lightwand.

RESULTS

Insertion was successful at the first attempt in 95.5% (86/90) and at the second attempt in 4.5% (4/90). Mean +/- SD airway sealing pressure at 30, 40, 50 and 60 mL cuff inflation volume was 27 +/- 8, 29 +/- 9, 32 +/- 9 and 35 +/- 7 cm H(2)O respectively; expired tidal volume at airway sealing pressure was 16 +/- 6, 18 +/- 6, 19 +/- 5 and 19 +/- 6 mL.kg(-1); and calculated mucosal pressure was 38 +/- 14, 55 +/- 20, 56 +/- 19 and 57 +/- 20 cm H(2)O. Airway sealing pressure, expired tidal volume at airway sealing pressure and calculated mucosal pressures increased with cuff inflation volume (all: P < or = 0.0002). Esophageal leak was detected in 9% (8/90), but only at peak pressures > or = 35 cm H(2)O and cuff inflation volumes > or = 40 mL. Lightwand-guided intubation was successful in 82% (74/90) of patients. Mild, moderate and severe blood staining was detected in 40% (36/90), 15% (13/90) and 1% (1/90) respectively. Blood staining was more frequent after adjusting maneuvers (22/54 vs 32/36, P = 0.002).

CONCLUSION

The PAX has a high insertion success rate and is an effective ventilatory device with a low risk of gastric insufflation, but has a moderately high failure rate for lightwand-guided intubation and is associated with a relatively high incidence of mucosal trauma. Mucosal pressures may exceed pharyngeal perfusion pressure.

A modified nasal trumpet to facilitate fibreoptic intubation

BACKGROUND

The modified nasal trumpet (MNT) is a standard nasopharyngeal airway with an added distal fenestration and fitted with a 15 mm adaptor to permit connection to an anaesthesia circuit.

METHODS

Based on its successful use as an emergency device in the 'cannot intubate, cannot ventilate' scenario, we considered that the MNT would aid fibreoptic intubation by providing a patent airway, spontaneous ventilation, and inhalation anaesthesia during the procedure. We report use of the MNT for this purpose seven times in six patients with difficult airways.

RESULTS

In each case, the MNT allowed oxygenation and general anaesthesia while maintaining spontaneous ventilation when awake intubation was unsuccessful or not possible.

CONCLUSION

The MNT has a place in the operating room suites as a useful airway management device.

A comparison of the laryngeal mask airway and PA(Xpress) for short surgical procedures

Sixty adult patients undergoing minor peripheral surgery under general anaesthesia were randomly allocated to receive either the laryngeal mask airway (laryngeal mask airway; size 4 for females and size 5 for males) or the PAXpress (adult size), inserted by a single operator with experience of > 50 insertions of each device. The laryngeal mask airway was correctly placed on the first attempt in 27 patients (90%) compared with 20 patients (67%) when using the PAXpress (p < 0.01). No patient required more than two attempts at insertion and there were no failures with the laryngeal mask airway, compared with four (13%) who needed three attempts and two failures (7%) with the PAXpress (p < 0.001 and p < 0.01, respectively). Mean (SD) total placement time was shorter with the laryngeal mask airway [24.6 (3.1) s] than with the PAXpress[35.4 (2.5) s; p < 0.01]. The most common complication was sore throat, which occurred less frequently with the laryngeal mask airway (8 patients; 26%) than with the PAXpress (15 patients; 53.5%; p < 0.001).

A comparison of the laryngeal mask airway ProSeal and the laryngeal tube airway in paralyzed anesthetized adult patients undergoing pressure-controlled ventilation

We compared the laryngeal mask airway ProSeal (PLMA) and the laryngeal tube airway (LTA), two new extraglottic airway devices, with respect to: 1) insertion success rates and times, 2) efficacy of seal, 3) ventilatory variables during pressure-controlled ventilation, 4) tidal volume in different head/neck positions, and 5) airway interventional requirements. One-hundred-twenty paralyzed anesthetized ASA physical status I and II adult patients were randomly allocated to the PLMA or LTA for airway management. A standardized anesthesia protocol was followed by two anesthesiologists experienced with both devices. The criteria for an effective airway included a minimal expired tidal volume of 6 mL/kg during pressure-controlled ventilation at 17 cm H(2)O with no oropharyngeal leak or gastric insufflation. First attempt success rates at achieving an effective airway were similar (PLMA: 85%; LTA: 87%), but after 3 attempts, success was more frequent for the PLMA (100% versus 92%, P = 0.02). Effective airway time was similar. Oropharyngeal leak pressure was larger for PLMA at 50% maximal recommended cuff volume (29 +/- 7 versus 21 +/- 6 cm H(2)O, P < 0.0001), but was similar at the maximal recommended cuff volume (33 +/- 7 versus 31 +/- 8 cm H(2)O). Tidal volumes (614 +/- 173 versus 456 +/- 207 mL, P < 0.0001) were larger and ETCO(2) (33 +/- 9 versus 40 +/- 11 mm Hg, P = 0.0001) lower for the PLMA. The number of airway interventions was significantly less frequent for the PLMA. Airway obstruction was more common with the LTA. When comparing mean tidal volumes in different head/neck positions, the quality of airway was unchanged in 56 of 60 patients (93%) with the PLMA and 42 of 55 (76%) with the LTA (P = 0.01). The PLMA offers advantages over the LTA in most technical aspects of airway management in paralyzed patients undergoing pressure-controlled ventilation.

IMPLICATIONS

The laryngeal mask airway ProSeal offers advantages over the laryngeal tube airway in most technical aspects of airway management in paralyzed patients undergoing pressure-controlled ventilation.

Application of nasal bi-level positive airway pressure to respiratory support during combined epidural-propofol anesthesia

STUDY OBJECTIVE

To examine whether nasal bi-level positive airway pressure (BiPAP) can be used as an airway during combined epidural-propofol anesthesia.

DESIGN

Prospective, consecutive case series study.

SETTING

Operating room at a general hospital.

PATIENTS

213 ASA physical status I and II adult patients undergoing lower extremity or lower abdominal gynecology surgery.

INTERVENTIONS

After epidural anesthesia, propofol was infused at 20 mg/kg/hr (P20) for 4 to 5 minutes followed by 5 mg/kg/hr (P5), and nasal continuous positive airway pressure (CPAP) 8 cm H(2)O and BiPAP 14/8 cm H(2)O was applied. In clinical situations, BiPAP with respiratory rate (RR) 10 breaths/min was applied. Furthermore, tidal volume (V(T)) during anesthesia, the effect of changing pressure support levels, and evaluation of pressure-controlled ventilation without spontaneous breathing were examined.

MEASUREMENTS AND MAIN RESULTS

CPAP resulted in a high RR, marked increased PaCO(2), and slightly decreased PaO(2), whereas BiPAP showed no change or a slightly decreased RR, slightly increased PaCO(2), and no change in PaO(2) or a great increase in PaO(2) with oxygen delivery. In clinical applications, similar results were found and anesthetic conditions were sufficient. Tidal volume increased after induction and maintained increased values under BiPAP 14/8 cm H(2)O. Of V(T) at 2, 6, or 10 cm H(2)O of pressure support levels, the 6 cm H(2)O was appropriate. Vecuronium injection showed a slight decrease and then increase in V(T) and PaCO(2), but the values were within normal (safe) limits. Respiration after rapid and high-dose infusion of propofol showed a markedly decreased RR, but the V(T) was maintained, and PaCO(2) and PaO(2) were at safe values. Rapid induction with 2.0 mg/kg propofol followed by P5 showed satisfactory results, in all but the obese patients.

CONCLUSIONS

BiPAP 14/8 cm H(2)0 with RR at 10 breaths/min during combined epidural-propofol anesthesia can be used to provide ventilatory support in lower extremity or lower abdominal gynecology surgery.

The use of the cuffed oropharyngeal airway in paediatric patients

BACKGROUND

The cuffed oropharyngeal airway (COPA) is a device which has already been demonstrated to be suitable for anaesthetized adult patients undergoing either spontaneous or mechanical ventilation. There are few reports on the use of the COPA in children. In this study, the authors assessed the COPA in paediatric patients undergoing minor surgery.

METHODS

The same anaesthesiologist inserted the COPA in 40 consecutive paediatric patients, ASA I and II, aged 1.8-15.3 years. (7.4 +/- 3.9), after induction of anaesthesia with N2O/O2/sevoflurane. COPA size was chosen by measuring the distal tip of the device at the angle of the jaw with the COPA perpendicular to the patient's bed. The proper positioning of the COPA was assessed by observing thoracoabdominal movements, regular capnograph trace, the reservoir bag movements and SpO2 > 94% with a fraction of inspired oxygen of 0.5. Anaesthesia was maintained with 1 MAC halothane, sevoflurane, or isoflurane in N2O/O2 (50%) and the patients were spontaneously breathing. The stability of the COPA following changes in head, neck and body position was tested. We recorded the duration time for COPA insertion, the side-effects of placement of the COPA and during the intraoperative period, the number of attempts, the type of manipulation in order to provide an effective airway and postoperative symptoms, such as the presence of blood on the device, sore throat, neckache, jaw pain and PONV.

RESULTS

Successful COPA insertion at the first attempt was 90% and at the second attempt in the remaining 10%. The most frequent airway manipulations were head tilt in 27.5% (obtained by a pillow under shoulders) and chin lift in 5%. No complications both at COPA placement nor during the intraoperative period were observed. On the basis of weight and age, the COPA size was no. 8 in 50%, no. 9 in 30%, no. 10 in 12.5%, and no. 11 in 7.5%. The COPA demonstrated stability after changes in head, neck and body position. Postoperative complications were the presence of blood stains in one case and PONV in six cases (15%).

CONCLUSIONS

The COPA is an extratracheal airway device suitable in paediatric patients undergoing general anaesthesia with spontaneous ventilation for minor surgery and other painful procedures. This study shows that for paediatric patients: (i) complications seem to be rare; (ii) the COPA allows hands free anaesthesia; (iii) specific indication for the COPA could be obese patients with a small mouth; and (iv) COPA sizing can be easily established by the weight or age of the patients.

Prehospital and resuscitative airway care: should the gold standard be reassessed?

In the context of prehospital care and resuscitation, tracheal intubation has been regarded as the standard in airway treatment. The evidence for this status is rather weak. It does not take into account the level of training and experience of the personnel attempting intubation, and whether they use neuromuscular blockers. In unskilled hands, attempted tracheal intubation is harmful; unrecognized esophageal intubation is disastrous. When healthcare providers lack adequate skills in tracheal intubation, alternative airway devices, such as the laryngeal mask airway or the Combitube, may be better options than a simple facemask. Healthcare personnel using any of these devices should be adequately trained and maintain frequent practice.

Gastroesophageal reflux and aspiration of gastric contents in anesthetic practice

General anesthesia may predispose patients to aspiration of gastroesophageal contents because of depression of protective reflexes during loss of consciousness. In addition, some patients may be at increased risk of pulmonary aspiration because of retention of gastric contents caused by pain, inadequate starvation, or gastrointestinal pathology resulting in reduced gastric emptying and gastroesophageal reflux. Despite increasing knowledge of the problems associated with aspiration, the relatively small incidence and associated mortality rates in the perioperative period do not appear to have changed markedly over the last few decades. In this review article, the physiological factors associated with an increased risk of gastroesophageal reflux and aspiration are considered together with some of the methods that are used to prevent aspiration. In particular, preoperative starvation, the use of drugs designed to increase gastric pH, recent developments in airway devices, and appropriate application of cricoid pressure are critically appraised.

Ease of ventilation through the cuffed oropharyngeal airway (COPA), the laryngeal mask airway and the face mask in a cardiopulmonary resuscitation training manikin

The aim of this study was to compare ease of ventilation of a cardiopulmonary resuscitation manikin using a cuffed oropharyngeal airway (COPA), a laryngeal mask airway (LMA) and a face mask, by two groups of people with different levels of earlier experience in cardiopulmonary resuscitation (CPR). Enrolled were, 108 people identified as experienced (54), or inexperienced (54), in CPR. Training equipment included a manikin, a COPA (n=10), an LMA (n=4), a face mask (n=4) and self-inflating bag-valve device. The same investigator explained the theoretical use and practice of the three techniques with the subjects in groups of three. The variables recorded were the number of attempts needed to achieve correct placement (and a tidal volume of 200 ml, was achieved), the insertion time for the COPA and the LMA, and the average time taken to achieve the first ten correct ventilations. The face mask and LMA required fewer attempts for correct placement than did the COPA. The LMA also took less time to insert than the COPA. The face mask required a significantly shorter total time with all attempts and the mean time of placement and time to achieve ten correct ventilations was shorter than with either the LMA or the COPA (P=0.0001). We conclude that the face mask offers an easier and quicker way to provide ventilation for CPR manikins than does the COPA or the LMA. Earlier experience affects the ease of insertion of the LMA and the total time needed to achieve effective ventilation.

A comparison of two techniques for manual ventilation of the lungs by non-anaesthetists: the bag-valve-facemask and the cuffed oropharyngeal airway (COPA) apparatus

In order to evaluate the possible role of the cuffed oropharyngeal airway during cardiopulmonary resuscitation, we compared its use by non-anaesthetists with the bag-valve-facemask technique of providing ventilation. A group of anaesthetic nurses and operating department practitioners were asked to manually ventilate the lungs of 40 patients undergoing elective surgery following the induction of general anaesthesia with neuromuscular blockade. Ventilation was first attempted using the bag-valve-facemask technique and then using the appropriate size cuffed oropharyngeal airway and self-inflating bag. Ventilation was clinically adequate in 32/40 (80%) patients using the bag-valve-facemask and in 38/40 (95%) patients using the cuffed oropharyngeal airway. Measured expired tidal volumes were greater using the cuffed oropharyngeal airway than with bag-valve-facemask ventilation in two-thirds of patients, despite a higher incidence of audible air leak. Successful ventilation was achieved using the cuffed oropharyngeal airway in seven of the eight patients in whom bag-valve-facemask ventilation was inadequate. The cuffed oropharyngeal airway may offer an effective method of providing ventilation during cardiopulmonary resuscitation by non-anaesthetic hospital staff, particularly when attempted ventilation using a bag-valve-facemask technique is proving ineffective.

An evaluation of the Airway Management Device

We have evaluated the Airway Management Device (AMD) in 105 anaesthetised patients. We were successful in establishing a clear airway on the first attempt on 69 occasions and unable to establish a patent airway at all in 10 patients. Airway obstruction requiring removal of the device occurred during maintenance of anaesthesia in a further two cases and during emergence in three. Loss of the airway during anaesthesia occurred in eight of 95 patients and could be reversed by manipulation of the airway in six cases. Overall, a mean of 0.56 manipulations per patient were required to establish an airway and a further 0.42 per patient were required during maintenance of anaesthesia. In the 95 patients in whom an airway was established, assisted ventilation was satisfactory in 93, with a leak pressure above 20 cmH2O in 65. Intracuff pressure was measured in 12 cases and was above 100 cmH2O in eight. Minor complications occurred in 12 patients. Blood was visible on removal of the device in six cases.

Causes of airway obstruction during cuffed oropharyngeal airway use

This study investigated the cause for needing airway maneuvers to maintain a patent airway during the use of cuffed oropharyngeal airway (COPA). Twenty adult patients (29.4+/-6.8 years-old, ASA 1-2) scheduled for minor gynecological surgery who required brief manipulations of the airway despite COPA use following the manufacture's guidelines, were enrolled in this study. To obtain airway patency, 15 patients required only the head-tilt maneuver. In eight of the 15 patients, the laryngeal inlet was opened partially (n=4) or completely (n=4). Despite lifting the epiglottis, the laryngeal inlet was incomplete at the level of pharyngeal view. The patency of the laryngeal inlet was decided by the extent of the distance between the posterior pharyngeal wall and the lateral glossoepiglottic fold, which was made by hyoid bone. In the other seven patients, the head-tilt maneuver elevated the epiglottis and completely opened the laryngeal inlet. Five patients required both the jaw-thrust and head-tilt maneuver. Of these patients lifting the epiglottis was incomplete in three and the laryngeal inlet was partially collapsed in one even after the airway manipulations. The airways in these three patients, however, became patent after manipulations despite the persisting partial obstruction.

Comparison of no airway device, the Guedel-type airway and the Cuffed Oropharyngeal Airway with mask ventilation during manual in-line stabilization

STUDY OBJECTIVE

To compare two different types of oropharyngeal airway: the Guedel-type oral airway and the Cuffed Oropharyngeal Airway (COPA), with respect to the effectiveness of positive-pressure ventilation (PPV) through a face mask in patients with in-line stabilization of the head and neck.

DESIGN

Prospective, randomized, crossover study.

SETTING

University hospital.

PATIENTS

30 ASA physical status I and II patients undergoing elective surgery.

INTERVENTIONS

General anesthesia was induced with propofol and muscle relaxation was produced with vecuronium. In a random sequence, no airway device, the Guedel-type airway, and the COPA were used in each patient while applying a face mask and lifting the jaw forward.

MEASUREMENTS AND MAIN RESULTS

Tidal volumes were measured during PPV in each option. The position of the distal tip of each airway was assessed using a fiberscope, and the resulting views were graded and compared. When the Guedel-type airway was used, tidal volumes (V(T)s; means +/- SD) were significantly greater (12.3 +/- 4.5 mL/kg) than those with no airway device (8.5 +/- 4.5 mL/kg) (p < 0.001). When the COPA was used, V(T)s (14.6 +/- 4.4 mL/kg) were significantly greater than those with the Guedel-type airway (p < 0.05). The grade of the fiberscopic view through the distal tip was significantly better with the COPA than with the Guedel-type airway (p < 0.05).

CONCLUSIONS

Although clinical differences often appear trivial, the COPA is more effective on mask ventilation than the Guedel-type airway when used in patients with manual in-line stabilization.

An evaluation of the cuffed oropharyngeal airway for elective pediatric anesthesia

STUDY OBJECTIVE

To evaluate the usefulness in pediatric patients of the cuffed oropharyngeal airway (COPA), an airway device with an inflatable cuff around its distal portion, and which provides airway patency in the majority of anesthetized adult patients.

DESIGN

Prospective evaluation.

SETTING

Pediatric operating room of a tertiary-care medical center.

PATIENTS

50 anesthetized ASA physical status I pediatric patients, under 6 yr of age undergoing elective surgery.

INTERVENTIONS

Patients were fitted with a size 7 COPA placed following anesthetic induction. If an adequate airway was not obtained, a size 8 COPA was placed. If an adequate airway was not obtained despite repositioning the size 8, the COPA was considered failed.

MEASUREMENTS AND MAIN RESULTS

The ease of insertion and ability to manage the airways were evaluated. Complications were evaluated on insertion, during maintenance, and upon awakening. The ability to positive pressure ventilate via the COPA was assessed. The size 7 COPA obtained an initial fit in 38 (76%) of the patients. Nine patients were managed with a size 8 COPA. The COPA was unsuccessful in 3 (6%) patients. Laryngospasm occurred in three patients. Blood was not visible on any of the COPAs. Positive pressure ventilation was achieved with 30 +/- 7 cm H(2)O pressure.

CONCLUSIONS

The results using the COPA in pediatric patients seem to parallel the experience of using larger sizes in adult patients.

Perioperative management issues in pediatric patients

Recent developments in perioperative practice, emphasizing issues that are of greatest concern in pediatric patients, are reviewed in this article. Many areas bear further evaluation in the evolving field of perioperative medicine: Effective techniques of psychologic preparation for children and their parents in an era in which the family rarely encounters the hospital environment before the day of surgery Application of newer intraoperative anesthetics, such as new narcotics and muscle relaxants, to shorten PACU and pediatric ICU stay while maintaining safety and comfort Critical evaluation of current methods of pain management to optimize comfort, while minimizing cost of such management in an increasingly cost-conscious health care environment The recent advent of a process for credentialing pediatric anesthesia fellowship programs, which requires a research component, bodes well for the prospect of finding answers to some of these questions.

Bridges to establish an emergency airway and alternate intubating techniques

In this article, a number of alternatives to direct laryngoscopy are examined. These alternatives include the laryngeal mask airway (LMA; LMA North America, San Diego, CA), cuffed oropharyngeal airway (COPA; Mallinckrodt, St. Louis, MO), and Combitube (Kendall-Sheridan, Mansfield, MA), that have been designed to act as bridges to establish an airway. Other devices, such as rigid stylets, the lightwand (a blind technique) and indirect fiberoptic rigid stylets, such as the Bullard scope, Upsher scope, and Wu scope are also briefly discussed.

Pediatric airway issues

Airway management in the pediatric patient requires an understanding and knowledge of the differences and characteristics unique to the child and infant. New and exciting techniques are currently being explored and developed for management of the pediatric airway. Technology in the area of imaging has allowed clinicians to better visualize the airway and aberrations of it. Presently, there are many different modes and routes of ventilation and oxygenation that are being applied to the pediatric patient for different disease states. Work continues to probe for methods and ways that will allow us to take care of infants and children better and to provide the safest and most effective means of delivering that care. No doubt, there will be more advances and exciting ideas to come that lead to better management of the pediatric airway.

Fast-tracking after immersion lithotripsy: general anesthesia versus monitored anesthesia care

Both monitored anesthesia care (MAC) and general anesthesia (GA) offer advantages over epidural anesthesia for immersion lithotripsy. We compared propofol-based MAC and desflurane-based GA techniques for outpatient lithotripsy. After receiving midazolam 2 mg IV, 100 subjects were randomly assigned to one of two anesthetic treatment groups. In the MAC group, propofol 50-100 microg. kg(-1). min(-1) IV was titrated to maintain an observer's assessment of alertness/sedation score of 2-3 (5 = awake/alert to 1 = asleep). Remifentanil 0.05 microg.kg(-1). min(-1) IV supplemented with 0.125 microg/kg IV boluses, was administered for pain control. In the GA group, anesthesia was induced with propofol 1.5 mg/kg IV and remifentanil 0.125 microg/kg IV and maintained with desflurane (2%-4% inspired) and nitrous oxide (60%). Tachypnea (respiratory rate >20 breaths/min) was treated with remifentanil 0.125 microg/kg IV boluses. In the GA group, droperidol (0.625 mg IV) was administered as a prophylactic antiemetic. Recovery times and postoperative side effects were assessed up to 24 h after the procedure. Compared with MAC, the use of GA reduced the opioid requirement and decreased movements and episodes of desaturation (<90%) during the procedure. Although the GA group took longer to return to an observer's assessment of alertness/sedation score of 5, discharge times were similar in both groups. We conclude that GA can provide better conditions for outpatient immersion lithotripsy than MAC sedation without delaying discharge.

IMPLICATIONS

A desflurane-based general anesthetic technique using the cuffed oropharyngeal airway device was found to be a highly acceptable alternative to propofol-based monitored anesthesia care sedation for outpatient immersion lithotripsy.

COPA as an aid for tracheal intubation

The purpose of this study is to verify the usefulness of the cuffed oropharyngeal airway (COPA) as a device to guide a tracheal tube using a semiblind technique with a lightwand. Ten anaesthetised patients (ASA I-II, aged 35-67) undergoing to an elective surgery were analysed. We selected and positioned a correct size of COPA for each patient. A lightwand (Trachlight) was then inserted into the COPA to confirm correct placement of this device. The lightwand was then removed and the first portion of a tube exchanger (TE) was inserted and connected by a 15-mm connector with the breathing circuit and its position was confirmed by End Tidal CO(2) values during ventilation. The patients were then paralysed and ventilation through the first portion of the TE reconfirmed. The COPA was removed, and the second portion of the TE was connected and used as a guide for a tracheal intubation. This combined technique had a success rate of six out of ten patients and could be used for airway management if a fibre optic scope or other devices such as a Combitube, LMA or LMA Fastrach were not available. The preliminary data from this study are not indicative of the statistical validity of this technique. Further studies should be performed to verify the statistical reliability of the technique.

Propofol dosage achieving spontaneous breathing during balanced regional anesthesia with the laryngeal mask airway

STUDY OBJECTIVE

To assess an anesthetic technique achieving spontaneous breathing through the laryngeal mask airway (LMA) during combined epidural block and propofol anesthesia.

DESIGN

Prospective, consecutive case series study.

SETTING

Operating room at a general hospital.

PATIENTS

112 ASA physical status I and II adult surgery patients; 32 patients for lower extremity surgery are enrolled into study 1, and 30 patients for lower extremity surgery and 50 patients for lower abdominal gynecology surgery are enrolled into study 2.

INTERVENTIONS

In study 1, patients were given 1.5 to 2.0 mg/kg followed by a 3 mg/kg/h of infusion of propofol, after epidural block, and they were fitted with the LMA. Thirty minutes after induction, the dose of propofol was increased to 4, 5, 6, and 7 mg/kg/h every 15 minutes. In study 2, the patients were given 1.5 to 2.0 mg/kg and 5 mg/kg/h of propofol and the LMA insertion, after epidural block.

MEASUREMENTS AND MAIN RESULTS

PaO(2)/FIO(2), PaCO(2), tidal volume or respiratory rate, blood pressure, heart rate, and eye opening and motor response scales in conformity with Glasgow coma scale were recorded. Study 1 suggested an induction dose of 1.5 to 2.0 mg/kg and an infusion of 5 mg/kg/h as an appropriate dose to preserve spontaneous breathing with the LMA and to maintain reasonable depth of anesthesia. Study 2 showed that respiratory and circulatory conditions, depth of anesthesia, and other data related to anesthesia were clinically acceptable.

CONCLUSIONS

The best infusion dose of propofol to achieve spontaneous breathing with the LMA seems to be 5 mg/kg/h, and the present balanced regional anesthesia with the LMA, using propofol infusion at 1.5 to 2.0 mg/kg and 5 mg/kg/h combined with epidural block, may be useful in clinical practice for lower extremity and lower abdominal gynecologic operations.

Airway management

The last decade of the millennium has witnessed the introduction of new extratracheal airway devices for use in fasted patients undergoing ambulatory anaesthesia. A growing awareness of the potential of such devices in the difficult airway has contributed to their increasing use.

Water flow between the upper esophagus and pharynx for the LMA and COPA in fresh cadavers. Laryngeal mask airway, and cuffed oropharyngeal airway

PURPOSE

In this randomised, crossover cadaver study, we determine the esophageal pressure (EP) at which water flow occurs between the upper esophagus and pharynx for the laryngeal mask airway (LMA) and cuffed oropharyngeal airway (COPA).

METHODS

Ten male and ten female cadavers were studied. The infusion set of a pressure controlled, continuous flow pump was inserted into the upper esophagus and ligated into place. The EP was increased in 2 cm H2O increments. This was performed without an airway device (controls) and over a range of cuff volumes for the LMA (0-40 ml) and COPA (0-60 ml). Regurgitation pressure (RP) was the EP at which fluid was first seen with a fibreoptic scope in the hypopharynx (controls) and above or below the cuff (LMA and COPA).

RESULTS

The RP was higher for the LMA than for the COPA and controls (P<0.0004), and RP was similar for COPA and controls. There was an increase in RP with increasing cuff volume for the LMA from 0 to 10 ml (P<0.0001). There were no increases in RP with increasing cuff volume for the COPA. The EP at which fluid leaked above and below the cuff was similar for the LMA at all cuff volumes. The EP at which fluid leaked above the cuff was higher than below the cuff for the COPA when the cuff volume was 40 ml (P<0.0001).

CONCLUSION

In fresh cadavers, the LMA provides better airway protection from fluid in the upper esophagus than the COPA.