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Biomedical subjects

I P Latto

Publications and source records attributed to I P Latto.

At least 19 recordsLinked to original sources

A comparison of simulated difficult intubation with multiple-use and single-use bougies in a manikin.

In a randomised cross-over study, 20 anaesthetists attempted to place a multiple- or single-use bougie in the trachea of a manikin, in which a grade 3 Cormack and Lehane laryngoscopic view was simulated. The anaesthetists made two attempts at placement with each bougie and were blinded to success (tracheal placement) or failure (oesophageal placement). The success rates for the first attempts with the multiple- and single-use bougies were 85 and 15%, respectively [mean (95% CI) difference between the two bougies 70% (40-84%); p < 0.001]. The success rates for the second attempts were similar to those for the first attempts with both bougies. There is an increased risk of failure to intubate the trachea when using a single-use bougie, and this must be weighed against the unquantified risk of cross-infection from prions when using a multiple-use bougie.

Clinical Competence↗

Prevalence of a training module for difficult airway management: a comparison between Japan and the United Kingdom.

To examine the education of trainees with regard to difficult airway management, we sent a questionnaire to all 89 Japanese University Departments of Anaesthesia (to be answered by a person who was responsible for teaching trainees) and all 280 Royal College of Anaesthetists' Tutors in the UK. The presence or absence of a formal training module for difficult airway management, timing and methods of training, types of airway devices that should be taught, and tutors' expertise with various techniques and devices were surveyed. Sixty-seven of the 89 Japanese tutors (75%) and 167 of 280 UK tutors (60%) replied to the questionnaire. Only 19 of 67 (28%) Japanese anaesthetists and 33 of 167 (20%) UK anaesthetists who replied, indicated that they had a difficult airway training module. In six Japanese departments (9%) and 115 (69%) UK departments, equipment for percutaneous transtracheal ventilation was readily available. Airway devices and techniques that tutors considered necessary to be mastered in the first 2 years of training, differed considerably between Japan and the UK, with notable differences in the use of gum elastic bougies and awake intubation. A training module for difficult airway management is often not provided and equipment for emergency transtracheal ventilation is often unavailable in both countries.

Anesthesiology↗

The rigid nasendoscope as a tool for difficult tracheal intubation: a manikin study.

We examined the use of the 30 degrees rigid nasendoscope in aiding difficult tracheal intubations. A Cormack and Lehane grade 4 difficult intubation (no view of glottis or epiglottis) was set up on a manikin. After 10 s of tuition, 40 anaesthetists attempted to pass a standard gum elastic bougie between the cords, with and without the nasendoscope, in randomised order. A bougie curved to an 'optimal curve' was also tested. Using the standard bougie 13/40 (33%) passed the bougie between the cords without the nasendoscope, compared with 31/40 (78%) when using the nasendoscope (p < 0.001). The 'optimal curve' bougie resulted in 29/40 (73%) and 39/40 (98%) success rates without and with the nasendoscope, respectively (p = 0.004). The nasendoscope is a simple and easy to use tool in grade 4 intubation, and results are improved further by the use of an 'optimal curve' bougie.

Attitude of Health Personnel↗

To shape or not to shape...simulated bougie-assisted difficult intubation in a manikin.

Thirty anaesthetists attempted to place a derived 'optimal' curve bougie or a straight bougie in the trachea of a manikin, in a randomised cross-over study. A Grade 3 Cormack and Lehane laryngoscopic view was simulated. The anaesthetists were blinded to success (tracheal placement) or failure (oesophageal placement). The success rates with the curved and straight bougies were 83 and 7%, respectively, giving a difference (95% confidence interval) of 77% (54-87%) between the two bougies (p < 0.0001). On a separate occasion, under identical laboratory conditions, 30 anaesthetists attempted to place a straight coudé (angled)-tipped bougie or a straight straight-tipped bougie in the trachea of a manikin. The success rates with the coudé- and straight-tipped bougies were 43 and 0%, respectively, giving a difference (95% confidence interval) of 43% (21-61%) between the two bougies (p < 0.001). These results suggest that bougies used to facilitate difficult intubation should be curved and have a coudé tip.

Clinical Competence↗

Survey of the use of the gum elastic bougie in clinical practice.

Data were collected prospectively on the use of the gum elastic bougie in 200 patients. The bougie was successfully inserted into the trachea and tracheal intubation was accomplished in 199 cases. The bougie was inserted into the trachea at the first attempt in 178 cases. In nine cases (4.5%) a second, more experienced, clinician was required. In 173 cases, the grades of view were recorded before and after the application of laryngeal pressure; pressure improved the view in 80 cases (46%), had no effect in 89 (51%) and worsened the view in four cases (2%). Various recommendations for optimal external laryngeal pressure and use of the bougie were not followed on 15-64% of occasions. There is a need for better education in these techniques.

Adolescent↗

Changes in serum S100beta protein and Mini-Mental State Examination after cold (28 degrees C) and warm (34 degrees C) cardiopulmonary bypass using different blood gas strategies (alpha-stat and pH-stat).

BACKGROUND: The effect of cardiopulmonary bypass temperature and blood gas management on the brain is still controversial. This study was designed to compare the changes in S100beta protein concentration and Mini-Mental State Examination in patients undergoing cold (28 degrees C) vs. warm (34 degrees C) cardiopulmonary bypass using different blood gas strategies (alpha-stat and pH-stat). METHODS: Sixty patients were randomly allocated to one of four equal groups (cold alpha-stat, cold pH-stat, warm alpha-stat, warm pH-stat). Serum S100beta concentrations were measured before CPB, directly after CPB, at 4.5 h and at 24 h after CPB. Mini-Mental State Examination was performed one day before surgery and on day five after the operation. Antegrade warm blood cardioplegia (37 degrees C) was used in all patients. RESULTS: There was no significant difference in postoperative S100beta protein levels between the four groups. Also, there was no interaction between bypass temperature and type of blood gas strategy on S100beta levels after bypass (directly after bypass, 4.5 h and 24 h after bypass). Mini-Mental State Examination score was not affected by blood gas strategy but it was significantly lower in patients undergoing cold cardiopulmonary bypass surgery: median (range), 26 (12-29) vs. 27 (23-30) in warm patients, P = 0.014. There was no significant correlation between Mini-Mental State Examination score 5 days after CPB and S100beta levels at any of the studied time-points after CPB. CONCLUSION: These results support the use of warm CPB (34 degrees C) in patients undergoing coronary artery bypass surgery regardless of the type of blood gas strategy.

Carbon Dioxide↗

Spatially resolved spectroscopy (NIRO-300) does not agree with jugular bulb oxygen saturation in patients undergoing warm bypass surgery.

PURPOSE: Near infrared spectroscopy (NIRS) is a promising non-invasive method for continuous monitoring of cerebral oxygenation during cardiac surgery with cardiopulmonary bypass (CPB). This study was designed to study the agreement between tissue oxygen index (TOI) measured by spatially resolved spectroscopy (NIRO-300) and jugular bulb oxygen saturation (SjO2) in patients undergoing warm coronary bypass surgery. METHODS: Seventeen patients undergoing warm coronary artery bypass surgery were studied. NIRS was continuously monitored and was averaged before CPB, five, 20, 40, 60 min on CPB, five minutes before end of CPB and ten minutes after CPB to coincide with SjO2 measurements. Bypass temperature was maintained at 34-37 degrees C. RESULTS: Bland and Altman analysis showed a bias (TOI-SjO2) of -6.7%, and wide limits of agreement (from 16% to -28%) between the two methods. In addition, mean TOI was lower than mean SjO2 during and after CPB. We observed a statistically significant correlation between arterial carbon dioxide and SjO2 measurements (r2=0.33; P=0.0003), but the former did not correlate with TOI values (r2=0.001; P=0.7). CONCLUSION: Our results demonstrate a lack of agreement between SjO2 and TOI for monitoring cerebral oxygenation during cardiac surgery. We conclude that the two methods are not interchangeable.

Aged↗

Changes in jugular bulb oxygenation in patients undergoing warm coronary artery bypass surgery (34-37 degrees C).

BACKGROUND AND OBJECTIVE: Imbalance between cerebral oxygen supply and demand is thought to play an important role in the development of cerebral injury during cardiac surgery with cardiopulmonary bypass. METHODS: We studied jugular bulb oxygen saturation, jugular bulb oxygen tension, arterial-jugular bulb oxygen content difference and oxygen extraction ratio in 20 patients undergoing warm coronary artery bypass surgery (34-37 degrees C) with pH-stat blood gas management. RESULTS: Only two patients showed desaturation (jugular bulb oxygen saturation < 50%) at 5 min on bypass, and none from 20 min onwards. Multiple regression models were performed after using bypass temperature, mean arterial pressure, cerebral perfusion pressure, haemoglobin concentration and arterial carbon dioxide tension as independent variables, and arterial-jugular bulb oxygen content difference, jugular bulb oxygen saturation, oxygen extraction ratio and jugular bulb oxygen tension as individual dependent variables. CONCLUSIONS: We found that jugular bulb oxygen saturation, jugular bulb oxygen tension and oxygen extraction ratio are mainly dependent on arterial carbon dioxide tension, and arterial-jugular bulb oxygen content difference is dependent on arterial carbon dioxide tension and the bypass temperature. Our results suggest jugular bulb oxygenation is mainly dependent on arterial carbon dioxide tension during warm cardiopulmonary bypass.

Aged↗

Early release pattern of S100 protein as a marker of brain damage after warm cardiopulmonary bypass.

Warm blood cardioplegia may be more beneficial to the heart than cold cardioplegia, but the effects of warm cardiopulmonary bypass and warm blood cardioplegia on the brain are controversial. S100 protein is an early marker of brain damage and has been detected after cold cardiopulmonary bypass. We studied S100 concentrations in 20 patients undergoing coronary artery bypass surgery before and after warm cardiopulmonary bypass (34-37 degrees C) using warm blood cardioplegia (37 degrees C) for all patients. The peak level of S100 protein occurred immediately after warm cardiopulmonary bypass, then decreased progressively until the last measurement at 4.5 h after bypass. The peak level appears to be dependent upon the age of the patient, with the following regression equation: y = -3.2 + 0.08x, where y is S100 protein concentration in microg.l-1 and x is patient age in years. Further studies are needed to investigate the clinical significance of this early release pattern. Patient age should be taken into account when studying S100 protein levels after cardiopulmonary bypass.

Adult↗

Respiratory complications associated with tracheal extubation. Timing of tracheal extubation and use of the laryngeal mask during emergence from anaesthesia.

Sixty patients were randomly allocated to one of three groups and the incidences of respiratory complications which occurred during emergence from anaesthesia were compared under the following three circumstances: tracheal extubation after the patient had regained consciousness (awake group); tracheal extubation while the patient was still anaesthetised (anaesthetised group); and the use of the laryngeal mask during emergence from anaesthesia (mask group). In the mask group, the laryngeal mask was inserted under deep anaesthesia before tracheal extubation and the lungs were ventilated through the laryngeal mask after tracheal extubation. In the awake group, straining (bucking) occurred in 18 patients and desaturation (arterial oxygen haemoglobin saturation < 95%) in two patients. In the anaesthetised group, airway obstruction occurred in 17 patients and desaturation in one of these patients. In the mask group, ventilation through the laryngeal mask was temporarily difficult immediately after tracheal extubation in one patient and coughing occurred before removal of the mask in three patients. No respiratory complications occurred in two patients in the awake group, three patients in the anaesthetised group and 16 patients in the mask group. The incidence of respiratory complications during recovery from anaesthesia was significantly lower in the mask group than in the other two groups (pooled) (p << 0.001). Therefore, the use of the laryngeal mask after tracheal extubation decreases the incidence of respiratory complications during recovery from anaesthesia.

Adolescent↗

The cuffed oropharyngeal airway. Its clinical use in 100 patients.

We studied the efficacy of the cuffed oropharyngeal airway in 100 patients. Insertion of the airway after induction of anaesthesia with propofol was easy in 95 of 100 patients, moderately difficult in four patients and failed in one patient. Complications, such as coughing, gagging or body movement, occurred during induction and insertion in 15 patients. Insertion of the airway was not associated with tachycardia or hypertension. Manual ventilation through the airway was easy in less than 30% of patients immediately after insertion. Manual ventilation became easier after adjusting the position of the patient's head, neck or jaw. During spontaneous breathing, adjustment of the head, neck or jaw was required in 30% of patients. Complete airway obstruction occurred in one patient after insertion of the device and in two patients during maintenance of anaesthesia. The airway was left in place during emergence from anaesthesia in the remaining 97 patients. No complications occurred in 91 patients and coughing occurred in the remaining six patients before or during removal of the airway. No regurgitation, vomiting or laryngospasm occurred in any patient at any time. Therefore, the cuffed oropharyngeal airway has a potential use in anaesthetised patients who are breathing spontaneously.

Adolescent↗

Effect of the size of a tracheal tube and the efficacy of the use of the laryngeal mask for fibrescope-aided tracheal intubation.

We randomly allocated 60 patients with normal airways into three groups to compare the ease of fibrescope-aided tracheal intubation using 8.0-mm internal diameter (group F8) and 6.0-mm (group F6) reinforced tracheal tubes and to evaluate the efficacy of the laryngeal mask as an aid for fibreoptic tracheal intubation (group L). In group F8 tracheal intubation was optimal in 2 of 20 patients and in two patients in whom intubation over the fibrescope was difficult the attempts resulted in inadvertent oesophageal intubation. In group F6 intubation was always successful and significantly easier than in group F8 (p < 0.005; 95% confidence interval for the difference in the proportion of the optimal intubation grade: 20-70%). In group L tracheal intubation was optimal in 18 of 20 patients and easier than in group F6 (p = 0.014; 95% confidence interval for difference: 10-60%). In both groups F6 and L tracheal intubation was completed within less than about 1 min. We conclude that conventional fibrescope-aided tracheal intubation with a 6.0-mm tracheal tube is easier than with an 8.0-mm tube and that the laryngeal mask facilitates fibrescope-aided tracheal intubation.

Adult↗