Ease Of Ventilation Research Articles

Comparison of Baska mask and I-gel with endotracheal tube in laparoscopic cholecystectomy: A randomized controlled study

Background: Supraglottic airway devices are frequently used instead of endotracheal intubation in laparoscopic surgeries. Two such devices, I-gel (IG) and Baska mask (BM), have been compared with respect to their sealing properties and leak fraction (LF) in comparison to the endotracheal tube. Aims and Objectives: The aim of the present study is to compare the performance of IG and BM with endotracheal tube in patients undergoing laparoscopic cholecystectomy under general anesthesia. Materials and Methods: In this randomized trial, 84 patients scheduled for laparoscopic cholecystectomy under general anesthesia were randomized to group (endotracheal tube [ETT], n=28), group BM (BM, n=28), or group IG (IG, n=28). All the patients received standard general anesthesia and the airway was maintained with either of three devices. The primary outcomes were the difference in the LF and airway sealing pressure (ASP) at different time points before and after pneumoperitoneum. Secondary outcomes were insertion-time, number of insertion attempts, and gastric insufflations. Heart rate and blood pressure were recorded. Complications such as sore throat, coughing, laryngospasm, blood staining of the device, and aspiration were noted. Results: P-values of LF of the three groups at time points T- after insertion (Ti), T-after pneumoperitoneum (Tp), and T- after peritoneal deflation (Tr) were 0.000 each and P-values of ASP at those time points were 0.000 each, respectively. Insertion time was significantly less for IG than ET (P<0.001). Heart rate and blood pressure showed P-values at Ti and Tp (P=0.004 and 0.000). Conclusion: It was concluded that IG or BM can maintain an airway with adequate seal and were not associated with any incidence of aspiration or laryngospasm. IG placement was found to be easier whereas the ease of ventilation was noted with BM.

Comparison of Laryngeal tube suction II (LTS II) and Proseal laryngeal mask airway (PLMA) for controlled ventilation in anaesthetised and paralysed adult patients

Background: LTS II and PLMA are supraglottic devices that may be used for ventilation in patients with normal as well as difficult airways at risk of aspiration. Aim: Comparison of LTS II with PLMA during controlled ventilation in paralysed patients with respect to time to successful insertion, success rate of insertion, attempts at repositioning, airway leak pressure, ease of ventilation and Ryle’s tube insertion, fibreoptic laryngeal view and complications. Methods: Thirty patients were studied using a prospective, randomised cross-over design. Ethical committee clearance and informed consent were obtained from all patients. Anaesthesia was induced with propofol and fentanyl and neuromuscular blockade achieved with vecuronium. Patients were divided into two groups: Group LTS and Group PLMA. In each group, the first airway device was inserted, various parameters observed and then removed. The second airway device was then inserted and the same parameters noted. Anaesthesia was continued with the second device in position. Results: Success with insertion at first attempt and time to insertion were comparable with both devices [LTS II 27/30 (17.5 s) and PLMA 29/30 (15.5 s) respectively]. PLMA required repositioning in fewer patients and provided better fibreoptic view than LTS II. Ryle’s tube insertion failed in four patients with PLMA but in none with LTS II. No significant difference was found in the airway seal pressure [mean, PLMA (27 cm H2 O) and LTS II (26.4 cm H2 O)], ease of ventilation or overall complications. Conclusion: Insertion and ventilation are comparable with PLMA and LTS II. Ryle’s tube insertion is easier with LTS II but requires more repositioning attempts and does not provide a good view of the larynx

Comparison of Macintosh laryngoscope, non- channelled (C-MAC video-laryngoscope) and channelled laryngoscope (Airtraq) for intubation in lateral position – A prospective randomized controlled study

BackgroundIntubation in the lateral position is desirable in several conditions but is challenging for the anaesthesiologist. The ideal tool to secure the airway in a lateral position remains unevaluated. We conducted this study to compare the intubation difficulty among the C-MAC video-laryngoscope with its Macintosh blade (Group C), direct laryngoscopy with a standard Macintosh blade (Group M), and the channelled optical laryngoscope Airtraq (Group-A) in the right lateral position. MethodsA prospective randomized controlled study was conducted on 120 patients, with 40 in each group, undergoing elective surgeries under general anaesthesia requiring oral tracheal intubation. The ease of ventilation, the success of intubation and the difficulty in intubation were assessed using the Intubation Difficulty Score (IDS). ResultsThe success rate of intubation was 100% with all the techniques and no major complication was noted. Time taken for glottic visualization was more in Group M as compared with the other two groups (p < 0.001). The total time required for intubation was shortest with the C-MAC (p < 0.001). IDS of 0 was observed in 36 patients (90%) in Group C and 29 patients (72.5%) in Group A and in 16 patients (40%) in Group M (p < 0.01). ConclusionVideo-laryngoscopes are preferable for intubation condition in the right lateral position. Airtraq did not offer any additional benefit over the C-MAC with its Macintosh blade in terms of reducing the time for intubation or ease of intubation.

Comparison and evaluation of single-use LMA supreme versus the reusable proseal LMA in paralyzed patients undergoing surgery with controlled ventilation.

Background and Aims:The objective of this prospective randomized blinded study was to assess the safety and efficacy of the laryngeal mask airway (LMA) Supreme as compared with the LMA Proseal.Material and Methods:A total of 60 patients were randomised into two groups to either receive a Proseal LMA (PLMA) or Supreme LMA (SLMA) for airway management. The primary outcome was to measure oropharyngeal leak pressure (OLP) in both groups. The secondary outcomes were the measurement of insertion time, insertion success rate, fibreoptic grading, intracuff pressure, ease of ventilation, and airway pressure on standard ventilatory settings and postoperative complications.Results:Intracuff pressure increase after 60 minutes of induction was significantly higher in the PLMA group (PLMA 97.43 ± 11.03 cm of H2O and SLMA 75.17 ± 8.95 cm of H2O). OLP was recorded after device insertion, after 30 min and after 60 min in each group and was found to be 28.71 ± 2.97, 30.93 ± 2.87, and 31.93 ± 2.72 cm of H2O in PLMA and 24.84 ± 2.08, 26.73 ± 2.26, and 27.95 ± 2.55 cm of H2O in SLMA group, respectively. The mean OLP with the SLMA was significantly (p=<.001) lower than PLMA. All the other parameters were comparable in both groups.Conclusion:PLMA is better than SLMA as airway device to ventilate at higher airway pressure in paralyzed adult patients. On the basis of our study, we recommend Proseal over Supreme LMA.

Comparison of one-handed C-E technique and glass holding technique of mask ventilation in anesthetized, apnoeic paediatric patients

Background: Successful and effective ventilation using a face mask is very basic, important and critical step in emergency resuscitation as well as in the operating room for pre-oxygenation of anesthetized apnoeic patients. Mask ventilation requires a good seal and a patent airway. Techniques for face mask ventilation include one-handed techniques and two-handed techniques. One-handed technique can be either classical C-E technique or glass holding technique. We aim to compare two one-handed techniques of mask holding in terms of delivered ventilation, mask leak and ease of performing. Method: All patients fulfilling inclusion and exclusion criteria were included after approval of the institutional ethics committee. After induction of general anaesthesia and confirming apnoea, patients with an odd serial number were first started with one-handed C-E technique then crossed over with glass holding technique while patients having even serial numbers were ventilated first with glass holding technique followed by the one-handed C-E technique. Expiratory tidal volume (VTe) and peak inspiratory pressure (PIP) and ease of ventilation for each breath in one minute were recorded. Results: VTe (mean ± SD) ml, Leak (mean ± SD) ml, PIP (mean ± SD) cmH2O was 94.94±25.22, 21.36±7.97, 18.05±2.99 and 101.78±28.18, 19.78±15.68, 16.52±1.95 for CE and Glass holding technique respectively. There is no significant difference between both the techniques in terms of analysed variables. (p-value > 0.05) Conclusion : Statistical analysis does not support that Glass holding technique is better than C-E technique in respect to studied variables. Still as results were comparable for both the groups, the Glass holding technique is a good alternative to C-E and other techniques of mask ventilation. Glass holding technique is very promising in view of ease of ventilation, decreasing procedural fatigue and reducing incidence and severity of tissue trauma, but further studies are required.

Postoperative Residual Neuromuscular Blockade (rNMB) Following Low-Dose (

Background: Low dose neuromuscular blockers, typically <2×ED95 or <0.46 mg/kg, have been shown to improve conditions of Laryngeal Mask Airway (LMA) placement and ease of ventilation during general anesthesia (GA), but its effects on the prevalence of residual neuromuscular blockage (rNMB) is poorly defined. A previous study in a large tertiary institution showed that 19% of patients undergoing GA with LMA received neuromuscular blockers. This study aims to audit the practice and establish the prevalence of rNMB. Methods: A cross-sectional, observational study was designed. Patients were included if they received a low dose of atracurium (<2×ED95). Quantitative neuromuscular monitoring with electromyography was performed on emergence upon removal of LMA (Train of Four ratio <0.9). Results: Two hundred patients were sampled randomly, 109 met the inclusion criteria. The overall prevalence of rNMB was 22.0% (average dose of atracurium (0.275 (± 0.093) mg/kg)). It was three times higher in patients who were not reversed (8.3% vs. 25.9%). The lack of use of reversal agents (OR 6.623, CI 0.030-0.771, p<0.05) and a shorter duration from the atracurium dose to emergence (OR 1.029, CI 0.956-0.988, p<0.05) were found to be associated with an increased risk of rNMB. Conclusion: Administering low-dose (<2×ED95) atracurium in patients receiving laryngeal mask airway still results in significant prevalence of residual neuromuscular blockade post-operatively. It is critical to monitor and reverse patients where appropriate.

Nondepolarizing muscle relaxant improves direct laryngoscopy view with no effect on face mask ventilation

Difficult or impossible face mask ventilation complicated with difficult tracheal intubation during anesthesia induction occurs in 0.4% of adult anesthesia cases, possibly leading to life-threatening complications. Because of such catastrophes, muscle relaxants have been recommended to be administered after confirming adequate face mask ventilation without a solid scientific validation of this principal. In this observational study, the ease of ventilation and the scores of direct laryngoscopy views before and after administration of cisatracurium were assessed in ninety young healthy adults, without anesthetic risks and without foreseen difficult intubation and who were scheduled for general elective surgeries. Before muscle relaxation, 43 patients (48%) were Cormack Grade I, while the remaining 47 patients (52%) were either Cormack Grade II (28 patients, 31%) or Cormack Grade II (19 patients, 21%). Following muscle relaxation with cisatracurium, the number of patients with Cormack Grade I significantly increased from 43 patients (48%) to 65 patients (72%) (p=0.0013). Only 1 patient out of 19 patients (5%) improved his Cormack grade from Grade III to Grade I while 16 out 19 patients (84%) improved their Cormack grade from Grade III to Grade II after the use of cisatracurium. The quality of face mask ventilation did not differ with and without muscle relaxants in all patients. The use of cisatracurium in healthy young adults undergoing general elective surgeries with no anticipated difficult endotracheal intubation had no effect on the quality of face mask ventilation despite resulting in a quantifiable improvement in the laryngeal view.

Keep pushing! Limiting interruptions to CPR; bag-valve mask versus i-gel® airway ventilation

Background: Recent recommendations made by ILCOR have de-emphasised the role of advanced airway management such as “endotracheal intubation” (ETI) during cardiac arrest in favour of maximising the number of chest compressions performed by rescuers. Maximising time available for compressions is achieved by minimising hands-off time (HOT). This has led to first responders and paramedics performing single rescuer CPR using a bag-valve-mask (BVM) device as opposed to the historical practice of intubating and ventilating via an endotracheal tube. Bag-valve-mask ventilations, especially during single rescuer CPR, are however associated with complications potentially resulting in increased ventilation times. More time spent on ventilations in the single rescuer scenario naturally leads to an increase in HOT and less time being available for compressions. It is postulated that the use of an appropriate supraglottic airway device (SAD) may decrease the time spent on the ventilation component of CPR and result in a decrease in HOT.Objectives: This pilot study evaluated how interruptions to chest compressions or hands-off time (HOT) are affected by the placement of an i-gel® airway vs. simple BVM ventilation during single rescuer CPR.Method: 16 participants performed two, ten-minute single rescuer CPR simulations, firstly using the BVM and later the i-gel® airway for ventilation. Data pertaining to ventilations and HOT in each scenario was statistically analysed and compared.Results: The i-gel® airway demonstrated a superior ease of ventilation compared to BVM alone and resulted in a reduction of time spent on ventilations overall. The i-gel® however took a mean of 29 s, ± 10 s, to secure which contributes considerably to HOT.Conclusion: The use of the i-gel® airway resulted in a considerable decrease in the amount of time spent on ventilations and in more compressions being performed. The overall reduction in HOT was, however, offset by the time it took to secure the device. Further investigation into the use and securing of the i-gel® airway in single rescuer CPR is recommended.

Nondepolarizing muscle relaxant improves direct laryngoscopy view with no effect on face mask ventilation

BackgroundDifficult or impossible face mask ventilation complicated with difficult tracheal intubation during anesthesia induction occurs in 0.4% of adult anesthesia cases, possibly leading to life-threatening complications. Because of such catastrophes, muscle relaxants have been recommended to be administered after confirming adequate face mask ventilation without a solid scientific validation of this principal. MethodsIn this observational study, the ease of ventilation and the scores of direct laryngoscopy views before and after administration of cisatracurium were assessed in ninety young healthy adults, without anesthetic risks and without foreseen difficult intubation and who were scheduled for general elective surgeries. ResultsBefore muscle relaxation, 43 patients (48%) were Cormack Grade I, while the remaining 47 patients (52%) were either Cormack Grade II (28 patients, 31%) or Cormack Grade II (19 patients, 21%). Following muscle relaxation with cisatracurium, the number of patients with Cormack Grade I significantly increased from 43 patients (48%) to 65 patients (72%) (p=0.0013). Only 1 patient out of 19 patients (5%) improved his Cormack grade from Grade III to Grade I while 16 out 19 patients (84%) improved their Cormack grade from Grade III to Grade II after the use of cisatracurium. The quality of face mask ventilation did not differ with and without muscle relaxants in all patients. ConclusionThe use of cisatracurium in healthy young adults undergoing general elective surgeries with no anticipated difficult endotracheal intubation had no effect on the quality of face mask ventilation despite resulting in a quantifiable improvement in the laryngeal view.

Comparison of three supraglottic airway devices for airway rescue in the prone position: A manikin-based study.

Background:Accidental extubation during surgery in prone position can be life-threatening. Supraglottic airway devices (SAD) have been used successfully in such situations to rescue the airway. However, which SAD would be most appropriate in this setting has not been described in the literature.Aims:The aim of our study was to determine the most appropriate SAD for securing airway in a prone position during accidental extubation.Materials and Methods:In the study, Airway Trainer (Laerdal) manikin was used for studying insertion of three SADs; I-gel, Laryngeal Mask Airway ProSeal™ (PLMA) and LMA Classic™ (CLMA) in the prone position. Forty anesthesia resident doctors participated in this study. The time taken for insertion; ease of insertion and ventilation; bronchoscopic view; and insertion score were compared among the three groups.Results:The time taken for I-gel insertion was significantly lesser (12.89 ± 3.94 seconds) as compared to CLMA (17.07 ± 3.5 seconds) and PLMA (25 + 4.78 seconds). Least resistance was encountered in the insertion of I-gel, while maximum resistance was experienced in PLMA group (22.5% vs. 90%). The maneuver required for optimal positioning was observed in 27.5% of PLMA insertion, 2.5% in CLMA while no maneuver was required in any of the I-gel insertion. Ease of ventilation was comparable in all three SADs. The bronchoscopic view and insertion score were significantly higher with I-gel as compared to CLMA and PLMA.Conclusion:All three SADs were successful as rescue devices during accidental extubation in the prone position. However, the ease of insertion was maximum with I-gel, followed by CLMA and PLMA.

Comparison of the use of laryngeal mask airway Supreme and laryngeal mask airway ProSeal in prone position for pilonidal sinus excision surgery

Background Surgeries that require the patient to be in the prone position represent a challenge to the anesthesiologist in terms of securing the airway and additional time and personnel required for induction in the supine position and shifting to the prone position. Use of the classic laryngeal mask airway (LMA) in the prone position is a subject of controversy; the ProSeal LMA may be more suitable as it forms a better seal and provides access to the stomach. LMA Supreme is a newly introduced single-use supraglottic device that shares common features of both the LMA ProSeal and the intubating LMA. Aim of this study The aim of the study was to compare the use of LMA ProSeal and LMA Supreme after induction of anesthesia in the prone position. Patients and methods The study included 80 adult male patients for pilonidal sinus excision surgery. They were randomly divided into two equal groups: group P and group S. The ProSeal was used in group P and the Supreme was used in group S. Ease of insertion, ease of ventilation, leakage of inspiratory gases, SpO 2 , EtCO 2 , blood on the airway device after removal, and postoperative incidences of sore throat were recorded. Results There was no statistical difference between the two groups in terms of age, BMI, or duration of surgery. Both devices provided good air seal and good ventilation. Blood-stained saliva and postoperative sore throat were found more with ProSeal use than with Supreme. Conclusion Allowing the patients to take the prone position themselves and then inducing general anesthesia and securing the airway either with ProSeal or with Supreme is a safe practice.

A comparison of the Supreme™ laryngeal mask airway with the Proseal™ laryngeal mask airway in anesthetized paralyzed adult patients: a randomized crossover study

The Supreme laryngeal mask airway (SLMA) is a new single-use advanced form of the Proseal laryngeal mask airway (PLMA). This study tested the hypothesis that the SLMA is equally as effective as the PLMA as a supraglottic ventilatory device in anesthetized paralyzed adult patients. Size 4 SLMAs and PLMAs were compared in a randomized crossover study involving 60 patients aged 21-75 yr and American Society of Anesthesiologists physical status I and II. Once the patients were anesthetized and paralyzed, the SLMA and the PLMA were inserted into each patient in random order. The primary outcome measure was the laryngeal seal pressure (LSP) at an intracuff pressure of 60 cm H(2)O. Secondary outcome measures included the ease of inserting the laryngeal mask airway devices (LMADs) and the fibreoptic position of the airway tube. There was no statistically significant difference in LSP between the SLMA and the PLMA. The mean LSP was 19.6 +/- 5.8 cm H(2)O and 20.9 +/- 6.7 cm H(2)O for the SLMA and the PLMA, respectively. There was a similarity between the SLMA and the PLMA regarding the number of attempts required and the duration for insertion. However, fibreoptic positioning was better with the PLMA than with the SLMA (P < 0.0001). The clinical performance of the SLMA as a ventilatory device is comparable with that of the PLMA, as illustrated by the similar LSPs. The inferior position of the SLMA airway tube compared with that of the PLMA does not affect its ease of ventilation.

Insertion and use of the LMA Supreme™ in the prone position*

We investigated whether insertion of an LMA Supreme and its use for maintenance of anaesthesia is feasible in the prone position. Forty adult patients positioned themselves prone and were given propofol until the Bispectral Index was < 50. A size-4 LMA Supreme was inserted by experienced anaesthetists. Ease of insertion, ease of ventilation, efficacy of seal, ease of gastric tube insertion, blood staining, postoperative sore throat, and other complications were recorded. Insertion was successful at the first and second attempt in 37 (92.5%) and 3 (7.5%) patients, respectively. The mean (SD) insertion time was 21 (15) s. Oropharyngeal leak pressure was greater in females than males (29 (4) vs 25 (4) cmH(2)O, respectively, p = 0.01). Adequate ventilation was achieved in all patients. Gastric tube placement was successful in all patients. The frequency of blood staining and sore throat was 7.5% each. No other complications were noted. We conclude that use of the LMA Supreme in the prone position by experienced users is feasible.

An Evaluation of the Rapid Airway Management Positioner in Obese Patients Undergoing Gastric Bypass or Laparoscopic Gastric Banding Surgery

A new positioning device, the Rapid Airway Management Positioner (RAMP, Airpal Inc., Center Valley, PA) was evaluated to determine if there was an improvement in either mask ventilation, direct laryngoscopy, or both with the use of the RAMP in this patient population. Fifty-one morbidly obese patients (BMI > 35kg/m(2)) undergoing elective bariatric surgery were enrolled. Ventilation and laryngoscopy was performed in the neutral and head-elevated laryngoscopy position (HELP). Direct laryngoscopy was performed noting the glottic view according to the Cormack-Lehane classification (Samsoon and Young, Anesthesiology 42:487, 1987). Mask ventilation was then recommenced. The HELP, or "ramped," position was achieved by inflating the RAMP, which was placed underneath the patient prior to entering the OR. Once proper HELP position was achieved, a second laryngoscopy was performed followed by endotracheal intubation. Two main outcomes were noted in the neutral and HELP positions: (1) laryngoscopic view and (2) ease of ventilation. The inflated ramped position provided greater ease of ventilation as compared to the neutral position (p = 0.0003). There was also a significant improvement in the glottic view in the ramped position (p = 0.04). Ease of intubation was perceived to be severely difficult among two, and overall use of the positioning device was found to be difficult among seven of the residents. The RAMP effectively positions morbidly obese patients in the HELP position. Ease of ventilation and laryngoscopic view were both improved with its use in this patient population.

Is It the Validation or Invalidation of the Airway Management Algorithm?

Veterans Affairs Medical Center and Saint Louis University, St. Louis, Missouri. govind_r@hotmail.comThe authors must be congratulated for undertaking the study attempting to answer the question of protocol-based airway management in the event of unanticipated difficult intubation.1However, this raises some serious questions about the content and conclusions of the study.First, we are unclear as to how the investigators have concluded that their local protocol-based approach to airway management in the event of unanticipated difficult intubation after induction is efficacious. In an 18-month interval, 100 patients who were anticipated to be easy to intubate on preoperative work-up were subsequently found to be difficult to intubate. Sixteen percent of these patients suffered severe hypoxemia. Although the authors have not provided any data regarding the incidence of hypoxemia at induction among the true positive participants, it is unlikely that the incidence in that population could be as high as 16%. One patient suffered significant dental trauma and one ended up aspirating gastric contents. In addition, 89 patients were subjected to multiple attempts at direct laryngoscopy. The authors fail to acknowledge that these adverse events could very well been the result of the sticking with the proposed airway algorithm. It appears that most of the patients suffered hypoxemia as a result of multiple attempts at laryngoscopy. Hypoxemia, as we understand, is a clear sign of ventilatory failure under these situations unless it is attributable to other causes. Failure to keep a substantial number of patients oxygenated highlights the inefficiency of the proposed algorithm. Unless the study was designed to evaluate the efficacy of the Intubating Laryngeal Mask Airway ™ (LMA North America, Inc., San Diego, CA) as a tool for rescue ventilation, the conclusion that 100 percent of the patients were successfully ventilated underestimates the significant problems at ventilation encountered by the anesthesiologists while following the algorithm.We are also unclear on what basis the authors claim that the study has validated the local protocol-based approach to airway management. The study has neither the design nor the power to answer this question, as we do not know what would happen if the anesthesiologist were not restricted by the protocol to the use of direct laryngoscopy, gum elastic bougie, Intubating Laryngeal Mask Airway ™, or the transtracheal jet ventilation. Whether anticipated or unanticipated, the approach to airway management in the event of failed intubation at induction depends on multiple factors. The result of preliminary laryngoscopy, the view of the glottis, the primary reason for intubation failure (is it the poor laryngoscopic view or the failure to pass the tube?), ease of ventilation with the mask, the muscle relaxant used, emergency or elective surgery, state of oxygenation of the patient, presence or absence of risk factors for aspiration, the condition of upper dentition, and, above all, the skill and expertise of the anesthesiologist all must be taken into account before defining the next step. A protocol-based approach like the one proposed by the investigators may limit anesthesia providers from applying individual problem-based solutions in the event of inadvertent difficult intubation. The end result: the patient with the poor dentition suffers dental trauma, the patient with full stomach may wind up aspirating gastric contents; failure of the Intubating Laryngeal Mask Airway ™ regardless of the cause (morbid obesity/limited mouth opening) commits the anesthesia provider to expose the patient to the risk of transtracheal jet ventilation although switching to simple a laryngeal mask airway or laryngeal tube might have solved that problem. A broad-based protocol that incorporates all the fundamental goals and objectives of airway management, e.g. , the American Society of Anesthesiologists airway protocol, allowing for stepwise evaluation based interventions while taking into account factors specific to operator skill and experience, available resources, and patient continues to be the most prudent approach to management of inadvertent difficult intubation.2Veterans Affairs Medical Center and Saint Louis University, St. Louis, Missouri. govind_r@hotmail.com

The Laryngeal Mask Airway Unique??? versus the Soft Seal??? Laryngeal Mask: A Randomized, Crossover Study in Paralyzed, Anesthetized Patients

We tested the hypothesis that ease of insertion, oropharyngeal leak pressure, fiberoptic position, ease of ventilation, and mucosal trauma are different for the Soft Seal laryngeal mask airway (SSLM) and the laryngeal mask airway Unique (LMA-U). Ninety paralyzed, anesthetized adult patients (ASA I-II; 18-80 yr old) were studied. Both devices were inserted into each patient in random order. Oropharyngeal leak pressure and fiberoptic position were determined during cuff inflation from 0-40 mL in 10-mL increments and at an intracuff pressure of 60 cm H(2)O. Ease of ventilation was determined by controlling ventilation for 10 min at 8 and 12-mL/kg tidal volume and recording hemoglobin oxygen saturation, end-tidal CO(2), leak fraction, peak airway pressure, and the presence or absence of gastric insufflation. Mucosal trauma was determined by examining the first randomized device for the presence of visible and occult blood. Insertion time was shorter (P = 0.0001) and fewer attempts were required (P = 0.005) for the LMA-U. There were no failed uses of either device. Oropharyngeal leak pressures were similar, but fiberoptic position was superior with the LMA-U (P < or = 0.0003). There were no differences in hemoglobin oxygen saturation, end-tidal CO(2), leak fraction, or peak airway pressure at either tidal volume. Gastric insufflation was not detected in either group at either tidal volume. The frequency of visible (P = 0.009) and occult blood (P = 0.0001) was less with the LMA-U. We conclude that the LMA-U is superior to the SSLM in terms of ease of insertion, fiberoptic position, and mucosal trauma, but similar in terms of oropharyngeal leak pressure and ease of ventilation.

Evaluation of prehospital insertion of the laryngeal mask airway by primary care paramedics with only classroom mannequin training

The laryngeal mask airway (LMAtrade mark airway) provides adequate ventilation and offers a suitable alternative for airway management in patients with cardiac arrest if primary care paramedics do not have intubation skills or are unable to intubate. Training in the use of the LMA usually occurs in the operating room. To describe the use of the LMA by paramedics in prehospital adult non-traumatic cardiac arrest patients after classroom mannequin training. The study took place in a suburban rural emergency medical service. This is a 2-phase observational study of the effect of paramedic training for LMA insertion using a mannequin and the success rate in the prehospital setting. All paramedics successfully completed classroom mannequin training. All subsequent prehospital adult non-traumatic cardiac arrest patients from mid-February 1999 to Mar. 31, 2000, were eligible. Subjective assessment of chest expansion, ease of ventilation and auscultation defined adequacy of ventilation. Data collected included the number of insertion attempts, reasons for failure, ease of insertion, adverse events and reasons for not attempting intubation. Statistical analysis comprised descriptive frequencies, chi-squared tests for comparison of categorical variables and analysis of variance for continuous variables. 208 paramedics (100%) successfully completed training. The mean number of attempts was 1, and only 4 (2.1%) paramedics required a second attempt with a mannequin. The paramedics' perception of ease of use comparing the LMA with a bag valve mask (BVM) was evenly distributed across the 3 descriptors: 70 (39%) scored the LMA as easier to use, 57 (31%) as more difficult, and 54 (30%) stated there would be no difference. Of the 291 arrests during the study period, insertion of the LMA was attempted in 283 (97.3%) and was successful in 199 (70%) patients. The LMA became dislodged in 5 (2.5%) cases and was removed in 12 (6%) to clear vomit from the airway. The overall success rate was 182 (64%). The incidence of regurgitation prior to attempted insertion of the LMA was 28% (79 patients). Success rates did not vary significantly with the incidence of vomiting prior to insertion (p = 0.11). The majority of the paramedics evaluated LMA insertion as Very easy 49/220 (22.3%) or Easy 87/220 (39.6%). Paramedic evaluation of ease of use varied with success (p = 0.001). This study reports a 100% training success rate with a mannequin and a 64% success with LMA insertion and ventilation in the field by paramedics among adult out-of-hospital non-traumatic cardiac arrest patients.

The Laryngeal Mask Airway ProSeal(TM) as a temporary ventilatory device in grossly and morbidly obese patients before laryngoscope-guided tracheal intubation.

We determined the efficacy of the laryngeal mask airway ProSeal(TM) (PLMA) as a temporary ventilatory device in morbidly obese patients before laryngoscope-guided tracheal intubation. Sixty patients (body mass index 35--60 kg/m(2)) scheduled for elective surgery, who preferred airway management under general anesthesia, were studied. The induction of anesthesia was with midazolam/fentanyl/propofol and maintenance was with sevoflurane 1%--3% in oxygen 100%. The PLMA was inserted and an effective airway established. Rocuronium was given IV for paralysis. Oropharyngeal leak pressure, ease of gastric tube placement, residual gastric volume, fiberoptic position of the airway/drainage tube, and ease of ventilation at a tidal volume of 8 mL/kg was determined. The PLMA was then removed and laryngoscope-guided tracheal intubation attempted. The number of insertion/intubation attempts (maximum two each) and time taken to establish an effective airway with each device were recorded. An effective airway was obtained at the first insertion attempt in 90% of patients (54/60) and at the second attempt in 10% (6/60). The time taken to provide an effective airway was 15 plus minus 7 s (7--42 s). Oropharyngeal leak pressure was 32 plus minus 8 cm H(2)O (12--40 cm H(2)O). The residual gastric volume was 36 plus minus 46 mL (0--240 mL). Positive pressure ventilation without air leaks was possible in 95% of patients (57/60). The vocal cords were seen from the airway tube in 75% of patients (45/60), but the esophagus was not seen. The fiberoptic view from the drainage tube revealed mucosa in 93% of patients (56/60) and an open upper esophageal sphincter in 7% (4/60). Tracheal intubation was successful at the first attempt in 90% of patients (54/60), at the second attempt in 7% (4/60), and failed in 3% (2/60). In these latter two patients, the PLMA was reinserted and surgery performed uneventfully with the PLMA. The time taken to tracheally intubate the patient was 13 plus minus 10 s (8--51 s). There were no episodes of hypoxia (SpO(2) <90%) or other adverse events. There were no differences in insertion success rate, or the time to successful insertion between the PLMA and laryngoscope-guided intubation. We conclude that the PLMA is an effective temporary ventilatory device in grossly or morbidly obese patients before laryngoscope-guided tracheal intubation. The laryngeal mask airway ProSeal(TM) is an effective temporary ventilatory device in grossly and morbidly obese patients before laryngoscope-guided tracheal intubation.

Hemodynamic and pharmacodynamic comparison of doxacurium and high-dose vecuronium during coronary artery bypass surgery: A cost-benefit study

Doxacurium (DOX), a new nondepolarizing neuromuscular blocking drug (NMBD), was compared in a randomized, double-blind fashion to high-dose vecuronium (VEC) in 60 coronary artery bypass grafting (CABG) patients. A third group of 15 patients older than 70 years of age (DOX-70) was added to compare the effects of DOX to VEC in the older population. Endpoints of the study were hemodynamic stability, ease of ventilation and intubation, anesthesiologist's satisfaction, drug interventions to correct hemodynamic instability, and total cost of the drug. Anesthesia was induced with fentanyl (30 μg/kg) along with the NMBD (DOX 80 μg/kg, VEC 400 pg/kg) over a 2-minute period. Following induction, heart rate (HR) and mean arterial pressure (MAP) were decreased (P < 0.01) in all groups. Tracheal intubation caused the HR to return to baseline in the DOX-70 group. There was no difference in central venous pressure, pulmonary artery occlusive pressure, cardiac index, systemic vascular resistance, and drug intervention for DOX and VEC. None of the patients had evidence of myocardial ischemia. There was a statistically significant but clinically irrelevant decrease in central venous pressure and systemic vascular resistance in the DOX-70 group. The durations of the induction and maintenance doses of DOX were similar in the younger and older patients. Although the intubating dose of VEC had a faster onset of action, this had no effect on the ease of ventilation, conditions for tracheal intubation, and overall anesthesiologist satisfaction. The total cost for each NMBD was not different. It is concluded that there are no clinical or cost-benefit advantages between doxacurium and high-dose vecuronium; they are both equally effective and cost approximately the same.

Failure of intravenous low dose midazolam to influence memory recall in drug paralysed post-operative patients sedated with papaveretum

Sedation of ventilated patients in the Intensive Care Unit generates a tension between adequate sedation to maintain comfort and ease of ventilation and over sedation with undesirable prolongation of ventilation and delays in discharge. Studies in animals suggest very low dose midazolam, but not higher doses, potentiate the sedative effects of opiates. We undertook a trial of opiate sedation versus opiate sedation plus low dose midazolam (lmg/hour) to determine whether a similar effect could be demonstrated in man. Although ventilator time and the duration of admission to Intensive Care was not prolonged by the addition of midazolam, we were unable to demonstrate any statistically significant benefit with regard to memory recall.