Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Intubation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,297 records · Page 72Linked to original sources
PubMed2000

Cricoid pressure applied after placement of laryngeal mask impedes subsequent fibreoptic tracheal intubation through mask.

We studied 70 patients to see if cricoid pressure applied after insertion of the laryngeal mask altered the success rate of tracheal intubation through the mask. After induction of anaesthesia and neuromuscular blockade, patients were randomly allocated to have either cricoid pressure (Group C) or sham pressure (Group S). The view of the glottis through the laryngeal mask was assessed before and after the test pressure, and tracheal intubation through the mask was attempted using a fibreoptic bronchoscope. The test pressure did not alter the view of the glottis in any patient in group S, whereas it narrowed the glottic aperture in 16 out of 35 patients in group C. The fibrescope was inserted into the trachea in all patients in group S and in 25 patients in group C. The success rate of tracheal intubation in group S (31 patients) was significantly higher than in group C (21 patients, P << 0.001; 95% CI for difference: 9-48%). The time for insertion of the fibrescope in group S (median (95% CI): 12 (11-12) s) was significantly faster than in group C (16 (14-17) s, P << 0.001; 95% CI for difference: 3-6 s), and the time for tracheal intubation in group S (16 (15-18) s) was significantly faster than in group C (22 (19-24) s, P < 0.0005; 95% CI for difference: 3-7 s). Cricoid pressure after insertion of the laryngeal mask makes tracheal intubation through the mask significantly more difficult.

Adolescent↗
PubMed2001

Sevoflurane EC50 and EC95 values for laryngeal mask insertion and tracheal intubation in children.

The laryngeal mask airway (LMA) is a simple, easy to use and safe method for airway control in children. Its insertion needs less anaesthetic, and haemodynamic responses and postoperative sequelae are less than with laryngoscopy and tracheal intubation. This study was designed to determine the end-tidal concentrations of sevoflurane where 50% (EC50) and 95% (EC95) of the attempts to secure the airway would be successful. We randomly assigned 40 children aged 4-12 yr undergoing general surgery to either LMA insertion (n=20) or to laryngoscopy and tracheal intubation (n=20) under sevoflurane anaesthesia. The initial end-tidal concentration of sevoflurane for each child was determined according to the response of the previous child in the same group. Up to three attempts to secure the airway with increasing sevoflurane end-tidal concentrations in 0.3% steps were allowed for each child. The logistic regression model was used to calculate the EC50 and EC95 values. Sevoflurane provided good conditions for both LMA insertion, and laryngoscopy and tracheal intubation without serious adverse effects. The EC50 and the EC95 of sevoflurane were 1.57 (SD 0.33)% and 2.22% for LMA insertion and 2.20 (SD 0.31)% and 2.62% for laryngoscopy and tracheal intubation. Thus, less sevoflurane is required for LMA insertion in children than for laryngoscopy and tracheal intubation.

Anesthetics, Inhalation↗
PubMed2002

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

BACKGROUND: We compared the effects of remifentanil and alfentanil on arterial pressure and heart rate at induction of anaesthesia and tracheal intubation in 40 ASA I-III patients aged greater than 65 yr, in a randomized double-blind study. METHODS: Patients received either remifentanil 0.5 microg kg(-1) over 30 s, followed by an infusion of 0.1 microg kg min(-1) (group R) or alfentanil 10 microg kg(-1) over 30 s, followed by an infusion of saline (group A). Anaesthesia was then induced with propofol, rocuronium, and 1% isoflurane with 66% nitrous oxide in oxygen. RESULTS: Systolic arterial pressure (SAP) and mean arterial pressure (MAP) decreased after the induction of anaesthesia (P<0.05) and increased for 3 min after intubation in both groups (P<0.05), but remained below baseline values throughout. Heart rate remained stable after induction of anaesthesia but increased significantly from baseline after intubation for 1 and 4 min in groups R and A, respectively (P<0.05). There were no significant between-group differences in SAP, MAP, and heart rate. Diastolic pressure was significantly higher in group A than group R at 4 and 5 min after intubation (P<0.05). Hypotension (SAP < 100 mm Hg) occurred in four patients in group R and three patients in group A. CONCLUSIONS: Remifentanil and alfentanil similarly attenuate the pressor response to laryngoscopy and intubation, but the incidence of hypotension confirms that both drugs should be used with caution in elderly patients.

Aged↗
PubMed2002

Prediction of the haemodynamic response to tracheal intubation: comparison of laser-Doppler skin vasomotor reflex and pulse wave reflex.

BACKGROUND: The laser-Doppler skin vasomotor reflex (SVmR) caused by tetanic stimulation of the ulnar nerve may be a test that can predict the haemodynamic response to tracheal intubation. A decrease in pulse wave amplitude (pulse wave reflex, PWR) may be an alternative index of this response. We compared the abilities of PWR and SVmR to predict the haemodynamic response to tracheal intubation and studied how alfentanil, muscle relaxation, stimulation site and stimulation pattern affected the two reflexes. METHODS: Anaesthesia was induced and maintained with 2% sevoflurane and 50% nitrous oxide in two groups of 10 ASA status 1 patients. Tetanic stimuli were applied to the flexor muscles of the forearm and the ulnar nerve before and after administration of vecuronium. The change in skin blood flow (laser-Doppler) and pulse wave amplitude (pulse oximetry) after a 5 and 10 s stimulation was measured on the opposite hand. If skin blood flow (laser-Doppler) decreased by more than 10%, a computer-controlled infusion of alfentanil was started and the target plasma concentration was increased in steps until this response was suppressed (< 10%). The trachea was intubated and arterial pressure and heart rate responses were recorded. Plasma alfentanil concentration was measured. RESULTS: When PWR and SVmR were suppressed, the haemodynamic response to tracheal intubation was reduced in 100 and 53% of patients respectively. PWR and SVmR responses decreased with increasing plasma alfentanil concentration. The SVmR response to muscle stimulation was reduced by muscle relaxants. The pulse wave response to both muscle and neural stimulation was reduced by relaxants. The responses to 5 and 10 s stimulations were similar. CONCLUSION: An absent SVmR does not predict a blunted arterial pressure or heart rate response to tracheal intubation. The PWR may be a better predictor.

Adult↗
PubMed2004

Changes in cortical electrical activity during induction of anaesthesia with thiopental/fentanyl and tracheal intubation: a quantitative electroencephalographic analysis.

BACKGROUND: There are regional differences in the effects of anaesthetics agents and perioperative stimuli on the EEG. We studied the topography of the EEG during induction of anaesthesia and intubation in patients receiving thiopental and fentanyl to document regional electrical brain activity. METHODS: EEG was recorded in 25 patients in the awake state, after pre-medication, during induction, at loss of consciousness and after intubation. Eight bipolar recordings were made and the relative power of the frequency bands delta, theta, alpha, and beta were used (after z-score transformation for age) to measure changes in regional EEG activity. RESULTS: Noxious stimulation during tracheal intubation partially reversed the slowing of the EEG caused by anaesthesia. During induction of anaesthesia alpha activity was most reduced in temporal and occipital regions. The most prominent EEG changes after intubation were an increase in alpha and a decrease in delta power (P<0.001). The largest changes were in the frontal and temporal leads for alpha and in the frontal and central leads for delta. Heart rate and arterial pressure remained constant during intubation. CONCLUSIONS: Changes in alpha and delta power were identified as the most sensitive EEG measures of regional changes in electrical brain activity during anaesthesia and noxious stimulation.

Adult↗
PubMed2004

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.

Adolescent↗
PubMed2006

The LMA CTrach, a new laryngeal mask airway for endotracheal intubation under vision: evaluation in 100 patients.

BACKGROUND: The LMA CTrach is a new laryngeal mask system consisting of an LMA CTrach Airway with integrated fibreoptic channels, and a detachable LMA CTrach Viewer. This system enables viewing of the larynx and aids endotracheal intubation through a laryngeal mask airway. Method. We used and evaluated this system in 100 adult patients undergoing general anaesthesia for elective surgery. Our primary outcomes were the success rates of LMA CTrach Airway insertion and endotracheal intubation with this system. RESULTS: We were able to insert the LMA CTrach Airway in and to ventilate all 100 patients. We were successful in endotracheal intubation, either under vision or blind, in 96 patients. We were able to view the larynx in 84 patients, but the quality of the best view obtained was very variable. The median (inter quartile range) time for the complete intubation process was 166 (114-233) s. The system allowed nearly continuous ventilation and oxygenation during the process. CONCLUSIONS: The LMA CTrach system has potential advantages over the LMA Fastrach system, including the ability to align the LMA outlet with the larynx and a high first intubation attempt success rate. However, it was difficult to view the larynx with the LMA CTrach compared with direct laryngoscopy, and expectations must be moderated.

Adult↗
PubMed2006

Effect of prophylactic bronchodilator treatment with i.v. carperitide on airway resistance and lung compliance after tracheal intubation.

BACKGROUND: Lung resistance increases after induction of anaesthesia. We hypothesized that prophylactic bronchodilation with i.v. carperitide before tracheal intubation would decrease airway resistance and increase lung compliance after placement of the tracheal tube in both smokers and nonsmokers. METHODS: Ninety-seven adults aged between 24 and 59 yr were randomized to receive i.v. normal saline (0.9% saline) (control) or carperitide, 0.2 microg kg(-1) min(-1) throughout the study. The 97 patients included smokers and nonsmokers. Thus the patients were allocated to one of the four groups: smokers who received normal saline (n=21), nonsmokers who received normal saline (n=27), smokers who received carperitide (n=19) or nonsmokers who received carperitide (n=30). Thirty minutes after starting normal saline or carperitide infusion, we administered thiamylal 5 mg kg(-1) and fentanyl 5 microg kg(-1) to induce general anaesthesia and vecuronium 0.3 mg kg(-1) for muscle relaxation. Continuous infusion of thiamylal 15 mg kg(-1) h(-1) followed anaesthetic induction. Mean airway resistance (R(awm)), expiratory airway resistance (R(awe)) and dynamic lung compliance (C(dyn)) were determined 4, 8, 12 and 16 min after tracheal intubation and compared between the four groups. RESULTS: At 4 min after intubation, R(awm) and R(awe) were higher and C(dyn) lower in smokers than in nonsmokers in the control group. R(awm) and R(awe) were lower and C(dyn) higher in smokers in the carperitide group than in smokers in the control group. R(awm) and R(awe) were lower in nonsmokers in the carperitide group than in nonsmokers in the control group. CONCLUSIONS: Marked bronchoconstriction occurred in the control groups (smokers and nonsmokers) 4 min after tracheal intubation. Prophylactic treatment with carperitide before induction of anaesthesia and tracheal intubation was advantageous, particularly in smokers.

Adult↗
PubMed2000

Comparison of different doses of remifentanil on the cardiovascular response to laryngoscopy and tracheal intubation.

We have compared three bolus and infusion regimens of remifentanil on the cardiovascular response to laryngoscopy and orotracheal intubation in three groups of 20 ASA I-II female patients, in a randomized, double-blind study. Patients in group 1 received glycopyrolate 200 micrograms i.v. followed by a bolus dose of remifentanil 1 microgram kg-1 over 30 s and an infusion of remifentanil at a rate of 0.5 microgram kg-1 min-1. The other patients received remifentanil 0.5 microgram kg-1 over 30 s and an infusion of 0.25 microgram kg-1 min-1 with (group 2) or without (group 3) pretreatment with glycopyrrolate 200 micrograms. All patients then received a sleep dose of propofol, rocuronium 0.6 mg kg-1 and 1% isoflurane with 67% nitrous oxide in oxygen. Laryngoscopy and tracheal intubation were performed 3 min later. Heart rate and arterial pressure were recorded at 1-min intervals from before induction of anaesthesia until 5 min after intubation. Baseline heart rate was similar in all groups, but decreased in group 3 (no glycopyrrolate) after induction and remained significantly lower after intubation compared with the other groups (P < 0.05). Heart rate and arterial pressure increased slightly after intubation in each group but there were no significant differences in mean arterial pressure between groups at any time. The incidence of bradycardia (one patient in group 2) and hypotension (two patients in groups 1 and 2 and three patients in group 3) was low.

Adult↗
PubMed2000

Effects of fenoterol and ipratropium on respiratory resistance of asthmatics after tracheal intubation.

We have studied the effects of a beta-agonist, fenoterol, and a cholinergic antagonist, ipratropium, on post-intubation total respiratory system resistance (Rrs) in asthmatics who developed increased Rrs after tracheal intubation. Sixteen stable asthmatics in whom Rrs increased after intubation were allocated randomly to receive either 10 puffs of fenoterol (group F) or 10 puffs of ipratropium (group IB) via a metered dose inhaler 5 min after intubation. Anaesthesia was induced and maintained with propofol i.v. Rrs was recorded before treatment and again 5, 15 and 30 min after treatment. Rrs decreased significantly from pretreatment values by mean 53 (SD 8)%, 53 (7)% and 58 (6)% at 5, 15 and 30 min, respectively, in group F, but declined by only 12 (6)%, 15 (4)% and 17 (5)% in group IB. At all times after treatment, patients in the fenoterol group had significantly lower Rrs values than those in the ipratropium group. We conclude that increased Rrs after tracheal intubation in asthmatics can be reduced effectively by treatment with fenoterol. A secondary finding of our study was that even after induction of anaesthesia with propofol, patients with a history of asthma may develop high Rrs.

Adrenergic beta-Agonists↗
PubMed1996

Propofol and alfentanil prevent the increase in intraocular pressure caused by succinylcholine and endotracheal intubation during a rapid sequence induction of anesthesia.

The increase in intraocular pressure (IOP) associated with succinylcholine (Sch) has made its use in patients with open globe injuries controversial. Studies that have examined techniques to prevent the increase in IOP due to Sch have shown a larger increase in IOP from the stimulus of laryngoscopy and endotracheal intubation. The purpose of our study was to examine whether the combination of propofol and alfentanil would prevent the increase in IOP due to Sch as well as endotracheal intubation during a rapid sequence induction of anesthesia. Sixty patients were randomized to receive either thiopental 5 mg/kg and Sch 1.5 mg/kg (Group I), propofol 2 mg/kg and Sch 1.5 mg/kg (Group II), or propofol 2 mg/kg, alfentanil 40 micrograms/kg, and Sch 1.5 mg/kg (Group III). The IOP was measured continuously from baseline awake (control) values until 15 s after successful intubation. All three groups had a significant decrease in IOP with the induction of anesthesia. Succinylcholine produced a consistent increase in IOP from the postinduction low in Groups I and II, but this increase was not significantly higher than baseline. The postintubation IOPs in Groups I and II were significantly higher than baseline (P < 0.001). During the entire study period, the IOP in Group III never increased above baseline. The IOP in Groups I and II had already begun to decline by 15 s postintubation, suggesting that laryngoscopy and intubation have the greatest effect on increasing IOP. We conclude that the combination of propofol and alfentanil prevents the increase in IOP from Sch as well as the increase associated with endotracheal intubation during a rapid sequence induction of anesthesia.

Adult↗
PubMed1998

Pneumoperitoneum as a risk factor for endobronchial intubation during laparoscopic gynecologic surgery.

UNLABELLED: Patients undergoing gynecological surgery under laparoscopic guidance usually receive general anesthesia with endotracheal intubation and mechanical ventilation. The creation of a pneumoperitoneum and the Trendelenburg position, both of which are used to improve visualization, are associated with cephalad movement of the diaphragm. This may increase the risk of endobronchial intubation. We studied the change in the distance from the tip of the endotracheal tube (ETT) to the carina with a fiberoptic bronchoscope in 30 patients aged 21-40 yr who were undergoing laparoscopic tubal ligation (n = 28) or hysterectomy (n = 2). Measurements were taken in the supine and Trendelenburg positions before and after pneumoperitoneum. The average distance from the ETT to the carina in the supine position was 2.1 +/- 0.8 cm and in the Trendelenburg position was 1.8 +/- 0.8 cm (P = not significant). After insufflation of the abdominal cavity, the mean distance decreased to 0.7 +/- 1.4 cm in the supine position (P < 0.05) and was associated with endobronchial intubation in eight patients. The addition of the Trendelenburg position to an established pneumoperitoneum resulted in minimal displacement (0.54 +/- 1.4 cm, P < 0.05) and one additional endobronchial intubation. We conclude that the insufflation of gas in the abdominal cavity, and not the change in patient position, is the main risk factor for endobronchial intubation in patients undergoing laparoscopic gynecologic surgery. IMPLICATIONS: This study demonstrated that in anesthetized women, the insufflation of gas into the abdomen during laparoscopy for gynecologic surgery is the main risk factor for migration of the endotracheal tube into a bronchus.

Adult↗
PubMed1998

Tracheal intubation with rocuronium using the "timing principle".

UNLABELLED: We compared the endotracheal intubating conditions after rocuronium, using the "timing principle," with those after succinylcholine. The timing principle entails administration of a single bolus dose of nondepolarizing muscle relaxant, followed by an induction drug at the onset of clinical weakness. Forty-five patients were randomly assigned to three groups. Patients allocated to Groups 1 and 2 received rocuronium 0.6 mg/kg. At the onset of clinical weakness (onset of ptosis), anesthesia was induced with thiopental 4-6 mg/kg; intubation was accomplished after 45 s in Group 1 and after 60 s in Group 2. Patients in Group 3 received vecuronium (0.01 mg/kg) 3 min before the administration of thiopental and succinylcholine 1.5 mg/kg, and their tracheas were intubated 60 s later by a blind anesthesiologist. Intubating conditions were assessed according to a grading scale and were either good (5 patients in Groups 1 and 2, 4 patients in Group 3) or excellent (10 patients in Groups 1 + 2, 11 patients in Group 3) in all patients. Patients were interviewed postoperatively, and all were satisfied with the induction of anesthesia. We conclude that rocuronium 0.6 mg/kg provides good to excellent intubating conditions 45 and 60 s after the induction of anesthesia using the timing principle. IMPLICATIONS: We compared the ease with which a breathing tube could be placed in patients using three techniques. The standard technique (succinylcholine) was compared with two others in which a muscle-relaxing drug (rocuronium) was administered just before the anesthetic drug (so-called timing principle). No difference among the techniques was observed.

Adolescent↗
PubMed2000

The effect of remifentanil on the bispectral index change and hemodynamic responses after orotracheal intubation.

UNLABELLED: In order to examine whether changes in the bispectral index (BIS) may be an adequate monitor for the analgesic component of anesthesia, we evaluated the effect of remifentanil on the BIS change and hemodynamic responses to laryngoscopy and tracheal intubation. Fifty ASA physical status I patients were randomly assigned, in a double-blinded fashion, to one of five groups (n = 10/group) according to the remifentanil target effect compartment site concentration (0, 2, 4, 8, or 16 ng/mL). The target-controlled infusion (TCI) of remifentanil was initiated 3 min after the TCI of propofol that was maintained at the effect-site concentration of 4 microg/mL throughout the study. After the loss of consciousness and before the administration of vecuronium 0.1 mg/kg, a tourniquet was applied to one arm and inflated above the systolic blood pressure in order to detect any gross movement within the first minute after tracheal intubation, which was performed 3 min after remifentanil TCI began. A BIS value was generated every 10 s. Arterial blood pressure and heart rate (HR) were measured every minute, noninvasively. Measures of mean arterial pressure (MAP), HR, and BIS were obtained before the induction, before the start of remifentanil TCI, before laryngoscopy, and 5 min after intubation. The relationships between remifentanil effect-site concentrations and BIS change or hemodynamic responses (changes in MAP and HR) to intubation were determined by logarithmic regression. BIS values were not affected by remifentanil before laryngoscopy. During this period, MAP and HR decreased significantly (P < 0.01) in the remifentanil 8 and 16 ng/mL groups. Changes in BIS, MAP, and HR were negatively correlated with remifentanil effect-site concentration (P < 0.0001). The number of movers in the remifentanil 0-, 2-, 4-, 8-, and 16-ng/mL groups was, respectively, 10, 9, 7, 1, and 0. Hypotensive episodes (MAP < 60 mm Hg) were noted in 1, 2, and 5 patients in the remifentanil 4-, 8-, and 16-ng/mL groups, respectively. We conclude that the addition of remifentanil to propofol affects BIS only when a painful stimulus is applied. Moreover, remifentanil attenuated or abolished increases in BIS and MAP after tracheal intubation in a comparable dose-dependent fashion. IMPLICATIONS: Bispectral index change is as sensitive as hemodynamic responses after a painful stimulus for detecting deficits in the analgesic component of anesthesia. It may, therefore, be a useful monitor of the depth of anesthesia in patients who are incapable of HR and MAP responses to noxious stimuli because of medications or cardiovascular disease.

Adolescent↗
PubMed2003

Endotracheal intubation device with a charge couple device camera.

We developed an orotracheal intubation device equipped with a charge couple device (CCD) camera, providing a wide field of vision. We used this device to perform endotracheal intubations in 62 anesthetized patients undergoing dental treatment and oral surgery. The time required to perform an endotracheal intubation with this system was examined. The use of this system is described below. The wand with the CCD camera was inserted into the oropharyngeal cavity. The oropharynx, including the epiglottis and glottis, could be visualized on the monitor screen. The tube introducer was inserted into the trachea through the vocal cords via the side tube of the wand. The wand with the CCD camera was withdrawn, leaving the tube introducer in the trachea. The endotracheal tube was then inserted into the trachea by using the tube introducer as a guide. The time required for the procedure was determined. The mean total time for the procedure was 41.2 s (maximum, 155 s; minimum, 14 s). There were no significant differences in this procedure when the patients were grouped according to the Cormack and Lehane classification. There was no failure to intubate using this system. Because the device can extensively visualize not only the larynx, glottis, and vocal cords, but also the movement of the tube introducer, on the monitor screen via the CCD camera, endotracheal intubation can be easily performed while the vocal cords are visualized on the monitor screen.

Adolescent↗
PubMed1985

Rapid tracheal intubation with vecuronium: the priming principle.

Following the administration of a single 0.1 mg/kg dose of vecuronium bromide, satisfactory conditions for tracheal intubation developed in 156 +/- 12 s (mean +/- SEM), and the clinical duration of the initial dose was 36 +/- 2 min. When the initial dose of vecuronium was administered in two increments, a 0.015 mg/kg "priming" dose, followed 6 min later by a 0.050 mg/kg "intubating" dose, intubation time decreased to 61 +/- 3 s and clinical duration to 21 +/- 1 min. The priming dose that had no unpleasant effect on premedicated, awake patients could be administered 3-4 min before, and the intubating dose 2 to 3 min after induction of anesthesia. With the described technique, comparable intubating conditions could be obtained just as rapidly with vecuronium as with succinylcholine chloride, without subjecting the patients to the side effects of and the complications occasionally encountered with succinylcholine. An added advantage of the use of a priming dose is that it will reveal undiagnosed, pathologic, or idiopathic increase of sensitivity to nondepolarizing muscle relaxants.

Adolescent↗
PubMed1994

Effect of prophylactic bronchodilator treatment on lung resistance after tracheal intubation.

BACKGROUND: After induction of anesthesia, lung resistance increases. We hypothesized that prophylactic bronchodilator treatment before tracheal intubation would result in a lower lung resistance after placement of the endotracheal tube. METHODS: Forty-two adult patients were randomized to receive one of three inhaled medications 1 h before surgery. All patients first underwent pulmonary function tests. Patients then received either inhaled albuterol (360 micrograms) (n = 12), inhaled ipratropium bromide (72 micrograms) (n = 15) or a placebo inhalation (n = 15). Two, 5, and 15 min after tracheal intubation, lung resistance was measured using the method of von Neergard and Wirtz. RESULTS: Patients who received either bronchodilator had significantly lower lung resistance after intubation than those receiving placebo. At 2 min, lung resistances were 12.7 +/- 1.4 cmH2O.l-1.s-1 (mean +/- SEM) for the placebo group, 6.4 +/- 3.1 cmH2O.l-1.s-1 for the ipratropium-treated group (P < 0.05 vs. placebo), and 7.2 +/- 0.8 cmH2O.l-1.s-1 for the albuterol-treated group (P < 0.05 vs. placebo). The differences in lung resistance persisted through the final measurement at 15 min. Three of fifteen placebo-treated patients developed audible wheezing whereas no patients developed wheezing in either bronchodilator-treated group (P < 0.05 by Fisher's exact test). Although smokers and nonsmokers in the placebo group developed similar resistances after intubation, bronchodilator treatment resulted in lower resistance in nonsmokers than in smokers (P < 0.05). CONCLUSIONS: Prophylactic treatment with either an inhaled beta 2-adrenergic agonist or an inhaled cholinergic antagonist produced lower lung resistance after intubation when compared with an inhaled placebo medication. The effect was more pronounced in nonsmokers than in smokers.

Administration, Inhalation↗
PubMed1996

Efficacy of the self-inflating bulb in confirming tracheal intubation in the morbidly obese.

BACKGROUND: This study was designed to determine the incidence of false-negative and false-positive results when the self-inflating bulb (SIB) is used to differentiate tracheal from esophageal intubation in morbidly obese patients using two techniques. In technique 1, the SIB is compressed before it is connected to the tube; in technique 2, the SIB is compressed after connection to the tube. METHODS: With institutional review board approval, 54 consenting adult morbidly obese patients (body mass index > 35) undergoing elective surgical procedures were included in the study. After anesthetic induction and muscle relaxation, both the trachea and esophagus were intubated under direct vision with identical cuffed tubes. The efficacy of the SIB in verifying the position of both tubes was tested by a second anesthesiologist. The speed of reinflation was graded as rapid ( < 4 s) or none ( > 4 s), using both techniques. In the case of tracheal intubation, the absence of reinflation was recorded as a false-negative, whereas in cases of esophageal intubation, rapid reinflation was recorded as a false-positive. Identification of tube location by the second anesthesiologist was based on SIB reinflation results from techniques 1 and 2, as well as the presence of a flatuslike sound elicited by technique 2 in esophageally placed tubes. All patients were retested by the SIB after receiving three breaths of 400-500 ml each. In all patients exhibiting false-negative results, six obese patients exhibiting true-positive results, and four nonobese patients exhibiting true-positive results, tracheal responses to the SIB maneuvers were observed directly by a flexible fiberoptic bronchoscope incorporating an airtight system, 15-20 min after mechanical ventilation was instituted. RESULTS: The incidence of false-negative results was initially 30% with technique 1 and 11% with technique 2, but decreased to 4% when technique 2 was used after the delivery of three breaths. The second anesthesiologist initially identified tube location in 92.5% of patients correctly. After the delivery of three breaths, tube location was correctly identified in 96.3% of patients. Fiberoptic bronchoscopic examination of the patients exhibiting false-negative results revealed exaggerated inward bulging of the posterior tracheal membrane during reinflation of the SIB when technique 1 was used. CONCLUSIONS: Contrary to previous investigations in healthy patients, the current study demonstrates a high incidence of false-negative results when the SIB is used to confirm tracheal intubation in morbidly obese patients. If the SIB is used, the technique should include compression of the SIB after connection to the tube and should be used in conjunction with other clinical signs and technical aids. The mechanism of false-negative results in these patients seems to be related to reduction of caliber of airways secondary to a marked decrease in functional residual capacity, and collapse of large airways due to invagination of the posterior tracheal wall when sub-atmospheric pressure is generated by the SIB.

Adolescent↗