[Low-dose droperidol in children: rescue therapy for persistent postoperative nausea and vomiting]. / "Low-dose"-Droperidol-Gabe bei Kindern: "Rescue"-Therapie gegen persistierende postoperative Übelkeit und Erbrechen.

BACKGROUND: Droperidol had been used as an effective antiemetic since the 1970s but was withdrawn from the market in 2001 because of a black box warning about QT prolongation and possible cardiac arrhythmia after high doses. In the meantime the black box warning has seriously been questioned and parenteral droperidol has again been licensed in 2008. Because droperidol acts on dopaminergic receptors different to 5-HT(3) antagonists and dexamethasone, it could possibly serve as a rescue drug after failed postoperative nausea and vomiting (PONV) prophylaxis. Persistent PONV after the recommended prophylaxis is a significant problem in pediatric anesthesia but a satisfactory strategy has not yet been defined. Therefore a retrospective audit was performed in order to evaluate whether low-dose droperidol (10 µg/kgBW) would be an effective rescue drug for failed antiemetic prophylaxis. PATIENTS AND METHODS: The electronic anesthesia patient data base of the University Children's Hospital Zurich was searched from 2004-2009 for patients who received low-dose droperidol in the postanesthesia care unit as rescue therapy for persistent PONV after antiemetic prophylaxis. Based on the recorded electronic data the effectiveness of low-dose droperidol as PONV rescue therapy and possible side effects were analyzed. RESULTS: A total of 338 patients who received droperidol were found from a total of 34,032 patients and the charts were analyzed. Of these patients 134 were excluded because they had received droperidol for indications other than PONV, 43 patients were excluded because they had not received antiemetic prophylaxis before droperidol and in 17 patients the data were incomplete, leaving 144 patients with an average age of 12.3 years (interquartile range IQR 9.5-15.2 years) for analysis. The upper range of ages resulted from patients with chronic diseases who were still being treated in the Children's Hospital. Low-dose droperidol was given because of persistent nausea to 59 patients (41%) and to 85 patients (59%) for persistent vomiting. Initial antiemetic prophylaxis and/or therapy had consisted of dexamethasone plus tropisetrone in 80 patients and tropisetrone or dexamethasone alone in 64 patients. In 128 patients (89%) rescue therapy with a median dose of 10.9 µg/kgBW droperidol was effective but vomiting persisted in 16 patients (11%). Sedation was the only side effect recorded and this was observed in 39 patients (27%). CONCLUSIONS: Low-dose droperidol (10 µg/kgBW) was found to be effective as rescue medication in pediatric patients experiencing PONV despite various prophylactic antiemetic regimens. No neurological or cardiopulmonary side effects were recorded after this low dosage.

[Intrathecal opioid medication for perioperative analgesia in severely handicapped children undergoing spinal operations]. / Intrathekale Opioidmedikation zur perioperativen Analgesie bei schwer behinderten Kindern mit Wirbelsäulenoperationen.

PURPOSE OF THE STUDY: Intrathecal opioids have been shown to be safe and effective for postoperative analgesia in healthy children for spinal surgery. The aim of this study was to evaluate the applicability of intrathecal opioids in severely handicapped children scheduled for spinal surgery. METHODS: With hospital ethical committee approval, patients with physical states III and IV of the ASA classification requiring spinal surgery were retrospectively studied. In addition to inhalational anesthesia with sevoflurane or intravenous anesthesia using propofol, morphine 20 microg/kgBW and sufentanil 1.5 microg/kgBW were administered intrathecally before surgery. After surgery an infusion of nalbuphine was started. Need for additional intraoperative and postoperative analgesics, time of extubation, postoperative pain scores and p(a)CO2 values as well as adverse effects were recorded. RESULTS: A total of 28 patients aged from 2.8 to 18.5 years (median 11.6 years) were studied. Immediate tracheal extubation in the operating room was possible in 17 patients and for 11 patients delayed extubation was elected. All patients were extubated within 24 h except for 1 patient who received massive postoperative transfusions. In 26 out of 28 patients (93%) the combination of intrathecal opioids with postoperative nalbuphine provided adequate analgesia. Observed side effects were post-operative nausea and vomiting (PONV), pruritus and moderate hypoventilation. In two patients a change to intravenous morphine therapy was necessary. CONCLUSION: The use of intrathecal opioids for perioperative pain control from spinal fusion in severely handicapped children is feasible. Intrathecal opioids provide adequate postoperative analgesia and allow early extubation without persisting relevant respiratory compromise in most of these patients.

Cuffed endotracheal tubes in children reduce sevoflurane and medical gas consumption and related costs.

BACKGROUND: This study aims to evaluate sevoflurane and anaesthetic gas consumption using uncuffed vs. cuffed endotracheal tubes (ETT) in paediatric surgical patients. METHODS: Uncuffed or cuffed ETT were used in paediatric patients (newborn to 5 years) undergoing elective surgery in a randomized order. Duration of assessment, lowest possible fresh gas flow (minimal allowed FGF: 0.5 l/min) and sevoflurane concentrations used were recorded. Consumption and costs for sevoflurane and medical gases were calculated. RESULTS: Seventy children (35 uncuffed ETT/35 cuffed ETT), aged 1.73 (0.01-4.80) years, were enrolled. No significant differences in patient characteristics, study period and sevoflurane concentrations used were found between the two groups. Lowest possible FGF was significantly lower in the cuffed ETT group [1.0 (0.5-1.0) l/min] than in the uncuffed ETT group [2.0 (0.5-4.3) l/min], P<0.001. Sevoflurane consumption per patient was 16.1 (6.4-82.8) ml in the uncuffed ETT group and 6.2 (1.1-14.9) ml in the cuffed ETT group, P=0.003. Medical gas consumption was 129 (53-552) l in the uncuffed ETT group vs. 46 (9-149) l in the cuffed ETT group, P<0.001. The total costs for sevoflurane and medical gases were 13.4 (6.0-67.3)euro/patient in the uncuffed ETT group and 5.2 (1.0-12.5)euro/patient in the cuffed ETT group, P<0.001. CONCLUSIONS: The use of cuffed ETT in children significantly reduced the costs of sevoflurane and medical gas consumption during anaesthesia. Increased costs for cuffed compared with uncuffed ETT were completely compensated by a reduction in sevoflurane and medical gas consumption.

Prospective randomized controlled multi-centre trial of cuffed or uncuffed endotracheal tubes in small children.

BACKGROUND: The use of cuffed tracheal tubes (TTs) in small children is still controversial. The aim of this study was to compare post-extubation morbidity and TT exchange rates when using cuffed vs uncuffed tubes in small children. METHODS: Patients aged from birth to 5 yr requiring general anaesthesia with TT intubation were included in 24 European paediatric anaesthesia centres. Patients were prospectively randomized into a cuffed TT group (Microcuff PET) and an uncuffed TT group (Mallinckrodt, Portex, Rüsch, Sheridan). Endpoints were incidence of post-extubation stridor and the number of TT exchanges to find an appropriate-sized tube. For cuffed TTs, minimal cuff pressure required to seal the airway was noted; maximal cuff pressure was limited at 20 cm H(2)O with a pressure release valve. Data are mean (SD). RESULTS: A total of 2246 children were studied (1119/1127 cuffed/uncuffed). The age was 1.93 (1.48) yr in the cuffed and 1.87 (1.45) yr in the uncuffed groups. Post-extubation stridor was noted in 4.4% of patients with cuffed and in 4.7% with uncuffed TTs (P=0.543). TT exchange rate was 2.1% in the cuffed and 30.8% in the uncuffed groups (P<0.0001). Minimal cuff pressure required to seal the trachea was 10.6 (4.3) cm H(2)O. CONCLUSIONS: The use of cuffed TTs in small children provides a reliably sealed airway at cuff pressures of

[Induction of anaesthesia and intubation in children with a full stomach. Time to rethink!]. / Anästhesieeinleitung und Intubation beim Kind mit vollem Magen. Zeit zum Umdenken!

Classical adult type rapid sequence induction (RSI) intubation is not always appropriate in children. In newborns, infants and small children, limited cooperation during pre-oxygenation, reduced respiratory oxygen reserves, increased oxygen demand and a tendency for airway collapse, easily lead to hypoxaemia after induction of anaesthesia. Gentle mask ventilation with pressures not exceeding 10-12 degrees cm H(2)O allows oxygenation without the risk of gastric inflation and aspiration. Risk factors leading to pulmonary aspiration are bucking, coughing and straining during induction or tracheal intubation and active regurgitation and vomiting during laryngoscopy under light anaesthesia and incomplete muscle paralysis. Gentle mask ventilation allows tracheal intubation under optimised oxygenation, haemodynamics, depth of anaesthesia and complete muscle relaxation. Application of cricoid pressure does not reliably prevent pulmonary aspiration. In children cricoid pressure clearly interferes with smooth induction of anaesthesia, results in difficult mask ventilation and intubation as well as provokes bucking and straining and, therefore, should not be routinely used. Key features of RSI intubation for children are effective induction of deep anaesthesia followed by profound muscle paralysis, careful mask ventilation and gentle tracheal intubation under optimised conditions.

Clinical evaluation of cuff and tube tip position in a newly designed paediatric preformed oral cuffed tracheal tube.

BACKGROUND: To assess the adequacy of the position of the tracheal tube cuff and tracheal tube tip in the recently introduced preformed oral Microcuff paediatric endotracheal tube (PET) using the manufacturers recommendations for Microcuff tracheal tube size selection. METHODS: With Hospital Ethics Committee approval and informed parental consent, the tracheas of children from birth to adolescence were orally intubated with the preformed oral Microcuff PET. First, the position of the tracheal tube's intubation depth mark in relation to the vocal cords was assessed. Second, the distance 'tracheal tube tip-to-carina' was endoscopically measured with the patient supine and the head in a neutral position and the tube placed with the centre mark at the lower incisors or alveolar ridge. RESULTS: A total of 166 children aged from 0.1 to 16.4 yr (median 5.9 yr) were studied. In five patients the intubation depth mark was above (5 mm each), in 22 patients at the level of and in the remaining 139 patients below the vocal cords. No endobronchial intubation occurred. In four patients the distance 'tracheal tube tip-to-carina' was smaller than the safety margin to prevent endobronchial intubation during head-neck flexion. CONCLUSION: The new oral preformed cuffed tracheal tubes allow safe placement in almost all patients when inserted according to the tube bend. The critically low tube tip and the high cuff positions in a few tubes when placed according to the tube bend requires clinical alertness.

Evaluation of a new recommendation for improved cuffed tracheal tube size selection in infants and small children.

BACKGROUND: The purpose of this study was to evaluate a new recommendation for tracheal tube size selection using second-generation Microcuff paediatric endotracheal tubes (PETs) with optimized outer diameter (OD) of the distal tube. METHODS: With Ethics Committee approval, patients aged from birth to 5 years, requiring general anaesthesia with orotracheal intubation, were included. Tracheal tube sizes were selected as follows: internal diameter (ID) 3.0 mm, birth (if > or =3 kg) to <6 months; ID 3.5 mm, 6 to <18 months; ID 4.0 mm, 18 months to <3 years; ID 4.5 mm, 3 to <5 years. Tracheal tubes with the cuff not inflated were classified as too large if no air leak was obtained at an airway pressure of < or =20 cmH2O. Post-intubation stridor requiring therapy was noted. RESULTS: Three hundred and fifty children were studied. Nine tracheal tubes (2.6%) were too large and had to be exchanged: in patients requiring tracheal tubes of ID 3.0 mm and 3.5 mm, three and four tracheal tubes, respectively, and, in patients requiring tracheal tubes of ID 4.0 mm and 4.5 mm, one tracheal tube in each group. In three patients (0.9%), post-intubation stridor occurred which required therapy. CONCLUSION: The new recommendation presented for the use of second-generation Microcuff PETs with improved OD to ID ratio allows the selection of cuffed tracheal tubes with larger IDs than previously recommended for small children without increased need for tracheal tube exchange or increased incidence of post-intubation stridor in these age groups.

Clinically relevant tracheomalacia after repair of esophageal atresia: the role of minimal intra-operative dissection and timing for aortopexy.

BACKGROUND: Tracheomalacia is associated with esophageal atresia (EA), but may go unnoticed from external splinting forces. Intra-operative dissection with fistula division releases external splinting, revealing tracheomalacia only post-operatively. Analysis of surgical technique may disclose an iatrogenic etiology. METHODS: From 1995 - 2004, 44 neonates underwent surgery for EA. All patients underwent pre-, intra- and postoperative bronchoscopy. Operative and bronchoscopic notes were studied for malacia, and extensive dissection of the esophagus and fistula from the trachea. RESULTS: Surgical mortality was 6.8 %. Pre-operative tracheomalacia was diagnosed in 3 patients, who eventually fared well. In 17 other patients, the pre-operative bronchoscopy was negative, but airway obstruction developed post-operatively. Tracheomalacia was documented at the site of the former fistula and surgical release maneuvers. Aortopexy was required in 5 instances, whereas 12 others with malacia were managed conservatively. CONCLUSIONS: Mediastinal connective tissue and the fistula may splint open the marginally diseased airway in patients with EA, the lack of which may disclose previously unknown tracheomalacia after repair. When aggressive release maneuvers have been required, early aortopexy may be preferred to ventilator dependency.

Tracheal tube-tip displacement in children during head-neck movement--a radiological assessment.

BACKGROUND: Aims of this study were to assess the maximum displacement of tracheal tube tip during head-neck movement in children, and to evaluate the appropriateness of the intubation depth marks on the Microcuff Paediatric Endotracheal Tube regarding the risk of inadvertent extubation and endobronchial intubation. METHODS: We studied children, aged from birth to adolescence, undergoing cardiac catheterization. The patients' tracheas were orally intubated and the tracheal tubes positioned with the intubation depth mark at the level of the vocal cords. The tracheal tube tip-to-carina distances were fluoroscopically assessed with the patient supine and the head-neck in 30 degrees flexion, 0 degrees neutral position and 30 degrees extension. RESULTS: One hundred children aged between 0.02 and 16.4 yr (median 5.1 yr) were studied. Maximum tracheal tube-tip displacement after head-neck 30 degrees extension and 30 degrees flexion demonstrated a linear relationship to age [maximal upward tube movement (mm)=0 0.71 x age (yr)+9.9 (R(2)=0.893); maximal downward tube movement (mm)=0.83 x age (yr)+9.3 (R(2)=0.949)]. Maximal tracheal tube-tip downward displacement because of head-neck flexion was more pronounced than upward displacement because of head-neck extension. CONCLUSIONS: The intubation depth marks were appropriate to avoid inadvertent tracheal extubation and endobronchial intubation during head-neck movement in all patients. However, during head-neck extension the tracheal tube cuff may become positioned in the subglottic region and should be re-adjusted when the patient remains in this position for a longer time.

Nitrous oxide diffusion into tracheal tube cuffs--efficacy of a new prototype cuff pressure release valve.

BACKGROUND: The aim of this study was to evaluate the performance of a new cuff pressure release valve (CPRV), in which the release pressure can be adjusted from 10 to 25 cmH2O, particularly intended to control pressure in paediatric cuffed tracheal tubes and to avoid cuff hyperinflation caused by N2O diffusion. METHODS: In vitro: the PRV was set to 10, 15, 20 or 25 cmH2O release pressure and connected to a cuffed tube placed into a box flushed with 66% N2O in O2. The cuff pressure was monitored with and without CPRV for 60 min. Experiments were performed four times using two different CPRVs. In vivo: with Institutional Review Board approval, CPRV was studied in 50 children undergoing general anaesthesia with tracheal intubation and standardized anaesthesia technique (including 66% N2O in O2) and ventilator settings. Patients were randomized into two groups (with and without CPRV). The cuff pressure baseline was 20 cmH2O and CPRV was set to 25 cmH2O. If the cuff pressure exceeded 25 cmH2O, it was manually released to 20 cmH2O. The numbers of deflations in both groups were noted and compared by Mann-Whitney U-test (P<0.05). RESULTS: In vitro: the cuff pressure exceeded 50 cmH2O after 60 min without CPRV, but did not exceed the settings with CPRV. In vivo: there was no need to manually deflate the cuff in the CPRV group but, in every patient in the control group, three (two to seven) deflating manoeuvres were required within the first hour of anaesthesia (P<0.0001). CONCLUSION: The CPRV allows reliable cuff pressure release at various pressure levels and reliably prevents cuff pressure increases caused by N2O.

Fit and seal characteristics of a new paediatric tracheal tube with high volume-low pressure polyurethane cuff.

BACKGROUND: To evaluate a new paediatric tracheal tube (Microcuff, Weinheim, Germany) with an ultrathin high volume-low pressure polyurethane cuff. METHODS: With approval of the Hospital Ethics Committee tracheas of children undergoing general anaesthesia were intubated using a Microcuff tube. Tube sizes were selected according to: internal diameter (mm) = age/4 + 3.5 in children aged > or = 2 years. In newborns (> or = 3 kg) < or = 1 year, ID 3.0-mm tubes, and in children from 1 to 2 years, internal diameter 3.5-mm tubes were used. Tubes were classified too large if no air leakage was obtained at an airway pressure of 20 cm H2O with the cuff not inflated. Sealing pressure was assessed by auscultation. Post-extubation croup requiring therapy was noted. RESULTS: Five-hundred children were studied. In eight children the tubes were too large. Sealing pressure was 9.7 +/- 2.5 cm H2O (4-20). In two patients postextubation croup required singular short-term therapy. CONCLUSIONS: Microcuff paediatric tracheal tubes provided tracheal sealing with cuff pressures considerably lower than usually accepted. The rate of tube exchange was very low (1.6%), as was the rate of airway morbidity (croup requiring therapy; 0.4%).

Appropriate placement of intubation depth marks in a new cuffed paediatric tracheal tube.

BACKGROUND: The aim of this study was to evaluate the appropriateness of intubation depth marks on the new Microcuff paediatric tracheal tube. METHODS: With local Institutional Ethics Committee approval and informed parental consent, we included patients from birth (weighing > or =3 kg) to 16 yr who were undergoing general anaesthesia requiring orotracheal intubation. Tracheal intubation was performed using direct laryngoscopy, the intubation depth mark was placed between the vocal cords, and the tube was taped to the lateral corner of the mouth. The distance between the tube tip and the tracheal carina was assessed by flexible bronchoscopy with the patients in supine, and their head in neutral positions. Tube sizes were selected according to the formula: internal diameter (ID; mm)=(age/4)+3.5 in children > or =2 yr. In full-term newborns (> or =3 kg) to less than 1 yr ID 3.0 mm tubes were used and in children from 1 to less than 2 yr ID 3.5 mm tubes were used. Endoscopic examination was performed in 50 size ID 3.0 mm tubes, and in 25 tubes of each tube size from ID 3.5 to 7.0 mm. Tracheal length and percentage of the trachea to which the tube tip was advanced were calculated. RESULTS: 250 patients were studied (105 girls, 145 boys). The distance from the tube tip to the carina ranged from 1.4 cm in a 2-month-old infant (ID 3.0 mm) to 7.7 cm in a 14-yr-old boy (ID 7.0 mm). Mean tube insertion into the trachea was 53.2% (6.3) of tracheal length with a minimum of 40% and a maximum of 67.6%. CONCLUSIONS: The insertion depth marks of the new Microcuff paediatric tracheal tube allow adequate placing of the tracheal tube with a cuff-free subglottic zone and without the risk for endobronchial intubation in children from birth to adolescence.

Nitrous oxide diffusion into tracheal tube cuffs: comparison of five different tracheal tube cuffs.

BACKGROUND: The aim of this study was to investigate cuff compliance and cuff pressure during nitrous oxide exposure in the recently introduced Microcuff tracheal tube with a polyurethane cuff (Microcuff GmbH, Weinheim, Germany), and to compare it to conventional tracheal tubes with PVC cuffs. METHODS: In an in vitro set up, five cuffed tracheal tubes (ID 7.0 mm) from different manufacturers (Microcuff HVLP, Portex Profile Soft Seal, Mallinckrodt HiLo, Rüsch Super Safety Clear and Sheridan CF) were studied. Pressure-volume curves were assessed and changes of cuff pressure during exposure to nitrous oxide (for 60 min; 66% N(2)O in oxygen) were recorded without and with restriction of the cuff in a trachea model. Each experiment was performed four times using two exemplars of each tube twice. Sixty-minute values of the Microcuff group were compared with the other groups using the Mann- Whitney test (P < 0.05). RESULTS: The Microcuff polyurethane cuff demonstrated an intermediate cuff compliance but the highest cuff pressure increase during nitrous oxide exposure under unrestricted conditions. When inflated within the artificial trachea its cuff compliance became the highest of all tested tracheal tubes. However, exposure to N(2)O, again led to a rapid increase in cuff pressure. CONCLUSION: The ultra-thin polyurethane tube cuff demonstrated higher permeability for nitrous oxide than conventional PVC cuffs and led to a rapid cuff pressure increase when exposed to N(2)O. Routinely checking of cuff-pressure or filling the cuff with nitrous oxide are more important than the brand of tube used.

Air leakage around endotracheal tube cuffs.

BACKGROUND AND OBJECTIVE: To compare the recently introduced Microcuff endotracheal tube with conventional tubes in respect of the cuff pressures required to prevent air leakage. METHODS: The following tubes (ID 7.0mm) were compared: Microcuff HVLP ICU, Mallinckrodt HiLo, Portex Profile Soft Seal, Rüsch Super Safety Clear and Sheridan CF. Fifty patients undergoing endotracheal intubation with a cuffed tube of internal diameter 7.0 mm were studied. Tracheas were intubated using one of the endotracheal tubes in random order. Cuff pressure to prevent air leakage at standardized ventilator setting (peak inspiratory pressure 20 cmH2O/PEEP 5 cmH2O/respiratory rate 15 breaths min(-1)) was assessed by auscultation of audible sounds at the mouth. Patients characteristics and cuff pressures from each brand were compared to the Microcuff group using the Mann-Whitney U-test (P < 0.05 was chosen as the level of statistical significance). RESULTS: Patients' median age (range) was 14.2 (12.0-17.1) yr, body weight 57.5 (40.0-81.9) kg and length 164.9 (146.5-190.0) cm. No significant differences in patients' characteristics were found between groups. Mean cuff pressure (all tubes) required for air sealing was 19.1 (8-42) cmH2O. The Microcuff tube required significantly lower sealing pressures (9.5 (8-12) cmH2O) compared to the other brands of endotracheal tube (P < 0.05, Mann-Whitney U-test). CONCLUSION: The Microcuff endotracheal tube with its ultra-thin polyurethane cuff membrane required the lowest sealing pressure to prevent air leakage. These features are potentially of interest for long-term intubated patients and for cuffed endotracheal tubes in children, allowing tracheal sealing at lower cuff pressures implying less damage to the trachea.

Non-invasive monitoring of haemoglobin concentration in paediatric surgical patients using near-infrared spectroscopy.

We evaluated the near-infrared spectroscopy based tissue haemoglobin index for continuous non-invasive monitoring of haemoglobin concentration during paediatric surgery. Blood samples from 40 children (from birth to 16 years old) were analysed oximetrically. From the first blood sample the tissue haemoglobin index/haemoglobin concentration coefficient was calculated for further tissue haemoglobin index-derived haemoglobin concentrations in each patient. Comparison of corresponding values revealed a bias and precision of -0.02 and 5.41 g.l(-1), respectively. Sensitivity and specificity of tissue haemoglobin index were 73.1% and 70.0%, respectively, for predicting falling haemoglobin concentration values. Currently, the tissue haemoglobin index is not suitable for monitoring haemoglobin concentration in children undergoing surgery.

[Microcuff pediatric tracheal tube. A new tracheal tube with a high volume-low pressure cuff for children]. / Der Microcuff Pädiatrietubus. Ein neuer Endotrachealtubus mit Hochvolumen-Niederdruck-Cuff für Kinder.

BACKGROUND: Principles and characteristics of the recently introduced Microcuff paediatric tracheal tube (Microcuff, GmbH, Weinheim, Germany) with anatomically based depth markings, cuff-free subglottic tube shaft and short high volume-low pressure cuff with ultrathin cuff membrane are presented. First available tubes (ID 4.0 mm) were evaluated regarding cuff pressures required to seal the trachea and regarding the distance from the tube tip to the carina. METHODS: After obtaining approval of the local ethical committee, 20 children aged 2-4 years, receiving tracheal intubation under general anaesthesia with muscle paralysis, were included. The tubes were placed during direct laryngoscopy and the glottic depth marking placed between the vocal cords. Cuff pressure to prevent audible air leakage at standardised ventilator settings (PIP 20 cm H(2)O/PEEP 5 cm H(2)O/RR20 x min(-1)) was assessed by means of a cuff pressure manometer within 5 min after intubation. Subsequently, the distance from the tube tip to the tracheal carina was measured by means of fibre bronchoscopy. Data are presented as the median (range). RESULTS: Patient age was 3.0 years (2.0-3.9 years), weight 13.5 kg (9.1-19.2 kg) and body length 95 cm (79-105 cm). The lowest cuff pressure required to seal the trachea ranged from 4-14 cmH(2)O (median 10 cm H(2)O), the distance from tube tip to tracheal carina was to 2.9 cm (2.0-4.5 cm). CONCLUSIONS: The new Microcuff paediatric tracheal tube with ultrathin high volume-low pressure cuff required tracheal sealing pressures below tracheal wall pressures usually required with uncuffed tracheal tubes for efficient sealing and ventilation at 20 cm H(2)O peak inspiratory pressure. The distance from the tube tip to carina was in the safe range in all patients.

Shortcomings of cuffed paediatric tracheal tubes.

BACKGROUND: The goal of this investigation was to evaluate adequacy of the design of readily available paediatric cuffed tracheal tubes (CPTT). METHODS: In 15 series of cuffed (11) and uncuffed (four) paediatric tracheal tubes (ID: 2.5-7.0 mm) from four different manufacturers the following dimensions were measured: outer diameter of the tube, position and largest diameter of the tube cuff inflated at 20 cm H(2)O and position of depth markings and compared with age-related dimensions. RESULTS: Outer diameters for tubes with similar IDs varied markedly between manufacturers and between cuffed and uncuffed tracheal tubes from the same manufacturer. Cuff diameters at 20 cm H(2)O cuff pressure and cross-sectional cuff area at 20 cm H(2)O cuff pressure did not always cover maximal internal age-related tracheal diameters and cross-sectional areas. Placing the tube tip in the mid-trachea, the cuffs of cuffed tubes with ID 3.0, 4.0, or 5.0 mm would become positioned within the larynx. If the cuffs were placed 1 cm below the cricoid level, many of the tube tips would be dangerously deep within the trachea. Only five of the 11 cuffed tubes had a depth marking. In many of these tubes the distances from depth marking to tube tip were greater than the age-related minimal tracheal length. CONCLUSION: Most cuffed paediatric tracheal tubes are poorly designed, in particular the smaller sizes. A better design of cuffed tubes with a short high-volume, low-pressure cuff, cuff-free subglottic space and adequately placed depth markings are urgently needed.

Warming of infusion syringes caused by electronic syringe pumps.

PURPOSE: To evaluate inadvertent warming of the infusion syringe in four different types of electronic syringe pumps. METHODS: Ambient temperature and syringe surface temperature were simultaneously measured by two electronic temperature probes in four different models of commercially available syringe pumps. Experiments were performed at an infusion rate of 1 ml h(-1) using both battery-operated and main power-operated pumps. Measurements were repeated four times with two pumps from each of the four syringe pump types at a room temperature of approximately 23 degrees C. Differences among the four syringe pump brands regarding ambient to syringe temperature gradient were compared using ANOVA. A P-value of less than 0.05 was considered statistically significant. RESULTS: Syringe warming differed significantly between the four syringe brands for both the battery-operated and main power-operated mode (ANOVA, P< 0.001 for both modes). Individual differences between syringe surface and ambient temperature ranged from 0.3 to 1.9 degrees C for battery operation and from 0.5 to 11.2 degrees C during main-power operation. CONCLUSION: Infusion solutions can be significantly warmed by syringe pumps. This has potential impact on bacterial growth and the stability of drug solutions and blood products infused, as well as on the susceptibility to hydrostatic pressure changes within the infusion syringe.