Dexmedetomidine and low-dose ketamine provide adequate sedation for awake fibreoptic intubation

A Randomized Comparison of Intravenous Versus Nebulized Routes for Administering Dexmedetomidine and Ketamine Combination to Facilitate Awake Fibreoptic Intubation

Introduction Awake fibreoptic intubation is a technique used to secure the airway of patients who are having predicted difficult intubation. We compared two routes, intravenous and nebulized, for administering a combination of ketamine and dexmedetomidine to patients requiring sedation for fibreoptic intubation. Methods and materials After approval of the institutional ethics committee, 64 patients between 18 and 60 years belonging to the American Society of Anesthesiologists physical status I or II and having predicted difficult airway were randomized to receive study medications through either intravenous (group I, n = 32) or nebulized (group N, n = 32) routes. Group I patients were given a combination of ketamine and dexmedetomidine through intravenous route. Group N patients were nebulized with a combination of ketamine and dexmedetomidine. The time required for awake fiberoptic intubation was the primary outcome variable. In addition, sedation score, cough severity, patient tolerance, intubating condition, hemodynamic changes, recall of events and discomfort during intubation, and any adverse events in the perioperative period were also compared. Results Compared to group N, the time needed to intubate the patients was significantly less in group I (75.69 ± 10.83 versus 49.19 ± 3.60 seconds, p < 0.001). Observer assessment sedation/alertness score (p < 0.001), cough severity (p < 0.001), patient tolerance (p < 0.001), and intubating condition (p = 0.001) were statistically significant, all conditions being better in group I. Patient discomfort and recall of the procedure were statistically similar between the groups. Conclusions The efficacy of a combination of dexmedetomidine and ketamine through the intravenous route is better than the nebulized route for patients undergoing awake fibreoptic intubation.

Near ideal anesthetic technique for tracheal stenting in central airway obstruction with dexmedetomidine-ketamine infusion: a case report

Central airway obstruction presents as an emergency with dyspnea and stridor. Anesthetic management of rigid bronchoscopy-guided tracheal stenting is highly stimulating procedure requiring general anesthesia. But it may lead to life threatening airway obstruction and cardiovascular collapse after induction. Total intravenous anesthesia based on propofol-remifentanil is an optimal anesthetic technique, but remifentanil is not available in many countries. Although dexmedetomidine-ketamine has been used for procedural sedation, its use for rigid bronchoscopy in the setting of central airway obstruction has not been described in literature. We describe near ideal anesthetic technique for management of central airway obstruction using dexmedetomidine-ketamine combination.

A comparison of two doses of ketamine with dexmedetomidine for fiberoptic nasotracheal intubation

Background and Aims:

Flexible fiber-optic intubation is considered to be the gold standard for management of difficult airway. Fiber-optic intubation does require effective sedation and blunting of airway reflexes for which various drug regimens have been utilized in the past. In a quest to find the noble drug combination, we combined ketamine and dexmedetomidine in two different doses, to evaluate the clinical efficacy and safety profile of ketamine and dexmedetomidine for fiber-optic intubation.

Materials and Methods:

This prospective randomized study was conducted in 72 patients of 20–50 years’ age group of either sex with the American Society of Anesthesiologists Physical Status I and II with difficult airway. We compared two doses of ketamine 20 mg (Group I) and 40 mg (Group II) with a common dose of dexmedetomidine at 1 μg/kg body weight, given as an infusion over 10 min (a solution of 50 ml with normal saline). Sedation scores, hemodynamic variables in terms of blood pressure, heart rate (HR), and oxygen saturation were studied along with 24-h postoperative patient discomfort and recall of procedure.

Results:

Group II patients showed less variation from their baseline values in terms of HR (ranged between 0.73% and 4.75%) and mean arterial pressure (ranged between 0% and 3.97%) in comparison to Group I HR (ranged between 0.09% and 9.81%) and mean pressures (ranged between 0.3% and 10.38%). Discomfort during procedure (P < 0.001) and recall of procedure scale (P = <0.001) were found significantly better/lower in Group II as compared to Group I.

Conclusion:

Ketamine 40 mg in comparison to 20 mg with dexmedetomidine provides better hemodynamic conditions with better tolerance and lower recall to the fiber-optic intubation.

Efficacy of Adding Low-Dose Ketamine to Dexmedetomidine Versus Low-Dose Ketamine and Propofol for Conscious Sedation in Patients Undergoing Awake Fiber-optic Intubation

Background and Aims:

Conscious sedation is the key for successful AFOI. This trial was conducted to compare the effectiveness of dexmedetomidine and low dose of ketamine against propofol and low dose ketamine.

Materials and Methods:

Sixty patients subjected for general anesthesia were invited to participate in the study and randomly allocated into two equal groups: D-K (n = 30) had been received a bolus dose of both ketamine 0.5mg /kg and dexmedetomidine 1ug/kg over 10 min. Then continuous infusion of ketamine 0.5mg /kg and dexmedetomidine 1ug/kg. The second group (P-K group) (n = 30): had been received a bolus dose of both ketamine 0.5mg/kg and propofol 1mg/kg over 10 min. Then continuous infusion of ketamine 0. 5mg/kg and propofol 1mg/kg.

Results:

The intubation time was statistically significant shorter within the D-K group (58.9 ± 6.1) versus P-K group (63.4 ± 5.3) with p-value 0.02. The shorter time needed to achieve the OAA/S score = 2 was in the D-K group (2.25 ± 0.75) versus (2.9 ± 0.79) in P-K group with (P-value 0.004). The intubation scores were insignificant different between both groups except vocal cord opening which was statistical better among D-K group with P-value 0.03. The significant hypotensive recorded data were among P-K group while the decreased heart rate were recorded in D-K group. Eighty percentages of patients had excellent score of satisfaction within the D-K gp against 47% among the patients within P-K gp with P-value 0.01.

Conclusion:

The concomitant administration of low dose of ketamine with dexmedetomidine had better intubation time and sedation scores with higher patient satisfaction scores than the combination of propofol and low dose of ketamine.

Dexmedetomidine in the Management of Awake Fiberoptic Intubation

Awake Fibreoptic Intubation (AFOI) is, nowadays, the gold standard in predicted difficult airway management. Numerous practice guidelines have been developed to assist clinicians facing with a difficult airway. If conducted without sedation, it is common that this procedure may lead to high patient discomfort and severe hemodynamic responses. Sedation is frequently used to make the process more tolerable to patients even if it is not always easy to strike a balance between patient comfort, safety, co-operation, and good intubating conditions. In the last years, many drugs and drug combinations have been described. This minireview aims to discuss the evidence supporting the use of Dexmedetomidine (DEX) in the AFOI management.

Myasthenia Gravis and Crisis: Evaluation and Management in the Emergency Department

BACKGROUND

Myasthenia gravis (MG) is an uncommon autoimmune disorder affecting the neuromuscular junction and manifesting as muscle weakness. A multitude of stressors can exacerbate MG. When symptoms are exacerbated, muscle weakness can be severe enough to result in respiratory failure, a condition known as myasthenic crisis (MC).

OBJECTIVE

This review discusses risk factors, diagnosis, management, and iatrogenic avoidance of MC.

DISCUSSION

MC can affect any age, ethnicity, or sex and can be precipitated with any stressor, infection being the most common. MC is a clinical diagnosis defined by respiratory failure caused by exacerbation of MG. Muscle weakness can involve any voluntary muscle. MC can be differentiated from other neuromuscular junction diseases by the presence of normal reflexes, normal sensation, lack of autonomic symptoms, lack of fasciculations, and worsening weakness with repetitive motion. Treatment should target the inciting event and airway support. All acetylcholinesterase inhibitors should be avoided in crisis, including edrophonium testing and corticosteroids initially. Respiratory support can begin with noninvasive positive-pressure ventilation, as this has been successful even in patients with bulbar weakness. If intubation is necessary, consider avoiding paralytics or use a reduced dose of nondepolarizing agents.

CONCLUSIONS

MC should be in the differential of any patient with muscular weakness and respiratory compromise. Emergency department management of MC should focus on ruling out infection and respiratory support. Strong consideration should be given to beginning with noninvasive positive-pressure ventilation for ventilatory support. Corticosteroids, depolarizing paralytics, and acetylcholinesterase inhibitors should be avoided in patients with MC in the emergency department.

A randomized double-blind controlled trial comparing three sedation regimens during flexible bronchoscopy: Dexmedetomidine, alfentanil and lidocaine

INTRODUCTION

No standardized sedation protocol is available for flexible bronchoscopy (FB).

OBJECTIVES

The aim of this study was to evaluate the efficacy and safety of three regimens used for sedation during FB.

METHODS

This randomized double-blind controlled trial assessed patients undergoing bronchoscopy and receiving lidocaine alone (C) or combined with dexmedetomidine (D) or alfentanil (A). Tolerance was assessed using the bronchoscopy score, and level of sedation was assessed using the Nursing Instrument for the Communication of Sedation. Safety was evaluated in terms of pulmonary function and vital signs.

RESULTS

A total of 162 patients were enrolled. The bronchoscopy score was identical in all groups. Group D subjects were the most sedated (P = .013), whereas group A subjects were the least agitated. Linear regression showed a negative association between bronchoscopy score and age in A (β = -0.06; P = .001). Positive predictors of bronchoscopy score were female gender (β = 1.96; P = .003) in D and obesity (β = 2.41; P = .012), longer procedures (β = 0.08; P = .009) and female gender (β = 1.15; P = .038) in C. Longer procedures (β = -0.12; P = .010) was a negative predictor of bronchoscopy score in D. Desaturation, hypoxia and heart rate changes were most prevalent in group A. Hypotension was mostly observed in D.

CONCLUSIONS

No consistent differences were present between the three regimens; however, each was more appropriate in certain patient profiles. We consequently proposed a protocol as a first step towards standardizing sedation practice in FB in a patient-tailored manner. A more comprehensive and detailed protocol including other sedative agents with their corresponding doses should be developed.

Dexmedetomidine-ketamine versus Dexmedetomidine-midazolam-fentanyl for monitored anesthesia care during chemoport insertion: a Prospective Randomized Study

Background

Dexmedetomidine as a sole agent showed limited use for painful procedures due to its insufficient sedative/analgesic effect, pronounced hemodynamic instability and prolonged recovery. The aim of this study was to compare the effects of dexmedetomidine-ketamine (DK) versus dexmedetomidine-midazolam-fentanyl (DMF) combination on the quality of sedation/analgesia and recovery profiles for monitored anesthesia care (MAC).

Methods

Fifty six patients undergoing chemoport insertion were randomly assigned to group DK or DMF. All patients received 1 μg.kg⁻¹ dexmedetomidine over 10 min followed by 0.2–1.0 μg.kg⁻¹h⁻¹ in order to maintain 3 or 4 of modified Observer's Assessment of Analgesia and Sedation score checked every 3 min. At the start of dexmedetomidine infusion, patients in group DK or DMF received 0.5 mg.kg⁻¹ ketamine or 0.05 mg.kg⁻¹ midazolam + 0.5 μg.kg⁻¹ fentanyl intravenously, respectively. When required, rescue sedatives (0.5 mg.kg-1 of ketamine or 0.05 mg.kg-1 of midazolam) and analgesics (0.5 mg.kg-1 of ketamine or 0.5 μg.kg-1 of fentanyl) were given to the patients in DK or DMF group, respectively. The primary outcome of this study was the recovery parameters (time to spontaneous eye opening and the length of the recovery room stay). The secondary outcomes were parameters indicating quality of sedation/analgesia, cardiorespiratory variables, and satisfaction scores.

Results

There were no significant differences in the onset time, time to spontaneous eye opening, recovery room stay, the incidences of inadequate analgesia, hypotension and bradycardia between the two groups. Despite lower infusion rate of dexmedetomidine, more patients in the DMF group had bispectral index (BIS) < 60 than in the DK group and vice versa for need of rescue sedatives. The satisfaction scores of patients, surgeon, and anesthesiologist in the DMF group were significantly better than the DK group.

Conclusions

The DK and DMF groups showed comparable recovery time, onset time, cardiorespiratory variables, and analgesia. However, the DMF group showed a better sedation quality and satisfaction scores despite the lower infusion rate of dexmedetomidine, and a higher incidence of BIS < 60 than the DK group.

Trial registration

Clinical Trial Registry of Korea KCT0000951, registered 12/12/2013

Comparison of Effects of Different Doses Dexmedetomidine on Inhibiting Tracheal Intubation-Evoked Haemodynamic Response in the Elderly Patients

BACKGROUND

Dexmedetomidine (DEX) is a selective α2-adrenergic receptor agonist with anxiolytic and analgesic properties. In the present study, we aimed primarily to assess the effects of DEX on sedation, cognitive function and cardiovascular reflex responses before, during and after the tracheal intubation in the elderly patients.

MATERIALS AND METHODS

Eighty patients undergoing elective abdominal surgery were randomly assigned to four Groups: Group A(saline, n=20), Group B (0.25μg/kg DEX, n=20), Group C (0.50μg/kg DEX, n=20) and Group D (1.00μg/kg DEX, n=20). With the constant speed infusion of saline and a loading different doses of DEX (diluted with saline to 50ml) for 10min respectively before induction of anaesthesia, the values of arterial pressure {systolic blood pressure (SBP), diastolic blood pressure (DBP)}, heart rate (HR) and bispectral index (BIS) at the time point of before pump DEX (T0), at the end of infusing DEX (T1), before tracheal intubation (T2), at the moment of tracheal intubation (T3) and 5min after trachea intubation (T4) were observed, oxygen saturation (SPO2) and the Modified Observers Assessment of Alertness/Sedation Scale (OAA/S) score were observed at the time of T1 and T0.

RESULTS

Comparison among Groups, compared with Group A, SBP and DBP values in Group C at T2 showed significant differences (p<0.05), SBP and DBP values in Group D at T1, T2 and T4 indicated significant differences (p<0.05), HR values in Group D at T1, T2, T3 and T4 showed significant differences (p<0.05); Compared with Group A, BIS values in Group C at T2 and T3 indicated significant differences (p<0.05), BIS values in Group D at T1, T2, T3 and T4 showed significant differences (p<0.05); Comparison between T3 andT2, means of SBP, DBP and HR in Group A and in Group B showed significant differences (p<0.05); Group D showed significant differences in SPO2 and (OAA/S) betweenT1 and T0 (p<0.05).

CONCLUSION

Comparison within Groups and between Groups in different doses DEX, the present result showed that 0.5μg/kg DEX had an effective inhibition, without respiratory depression, on tracheal intubation evoked cardiovascular response in the elderly patients.

The effect of KETODEX on the incidence and severity of emergence agitation in children undergoing adenotonsillectomy using sevoflurane based-anesthesia

BACKGROUND

Postoperative emergency agitation (EA) is a common problem often observed in children undergoing general anesthesia. The purpose of this study was to evaluate whether a bolus of intraoperative low-dose ketamine followed by dexmedetomidine i.v. could reduce the incidence of EA in children undergoing adenotonsillectomy following sevoflurane-based anesthesia.

METHODS

A total of 92 children undergoing adenotonsillectomy, aged 3-7 years, were randomly allocated to receive either low-doseketamine 0.15 mg/kg followed by dexmedetomidine 0.3 μg/kg i.v. (KETODEX, n=45) or volume-matched normal saline (Control, n=47), about 10 min before the end of surgery. Anesthesia was induced and maintained with sevoflurane. Postoperative pain and EA were assessed with objective pain score (OPS) and the Pediatric Anesthesia Emergence Delirium scale (PAED), respectively. EA was defined as a PAED≥10 points. Recovery profile and postoperative complications were recorded.

RESULT

The incidence and severity of EA was lower in KETODEX group than controls (11% vs. 47%) and (2% vs. 13%), respectively (P<0.05). The frequency of fentanyl rescue was lower in KETODEX group than in controls (13.3 vs. 38.3%, P<0.05). Heart rate during extubation was significantly higher in the control group compared with children who received KETODEX (P<0.05). The incidence of postoperative pain was significantly less in the KETODEX group (15.5% vs. 63.8%, P<0.05). Times to interaction and extubation were significantly longer in the KETODEX group (P<0.05).

CONCLUSION

KETODEX reduces the incidence and severity of EA in children undergoing adenotonsillectomy following sevoflurane-based anesthesia and provided smooth extubation.

Comparison between remifentanil and dexmedetomidine for sedation during modified awake fiberoptic intubation

Cricothyroid membrane injections and the application of a coarse fiberoptic bronchoscope (FOB) below the vocal cords for topical anesthesia have a number of limitations for certain patients. Thus, the aim of the present observational study was to assess the effect of a novel modified topical anesthesia method using the effective sedation drugs, remifentanil (Rem) or dexmedetomidine (Dex), during awake fiberoptic orotracheal intubation (AFOI). In total, 90 adult patients, who had been classified as American Society of Anesthesiologists I-II, were included in the study. The patients had anticipated difficult airways and were to undergo orotracheal intubation for elective surgery. The patients were enrolled in the double-blinded randomized pilot study and received Rem or Dex for sedation during the modified AFOI procedure. The two groups received 2% lidocaine for topical anesthesia via an epidural catheter, which was threaded through the suction channel of the FOB. The main clinical outcomes were evaluated by graded scores representing the conditions for intubation and post-intubation. Additional parameters analyzed included airway obstruction, hemodynamic changes, time required for intubation, amnesia level and subjective satisfaction. All 90 patients were successfully intubated using the modified AFOI technique. The comfort scores and airway events during intubation did not significantly differ between the two groups. However, the Rem group experienced less coughing, and less time was required for tracheal intubation when compared with the Dex group. No statistically significant differences were observed in the changes to the mean arterial pressure and heart rate at any time point between the two groups. Therefore, the current study demonstrated that the modified AFOI method is feasible and effective for difficult airway management, and that Dex and Rem exhibit similar efficacy as adjuvant therapies.

A comparison of dexmedetomidine plus ketamine combination with dexmedetomidine alone for awake fiberoptic nasotracheal intubation: A randomized controlled study

Background and Aims:

We designed a study to compare the effectiveness of dexmedetomidine plus ketamine combination with dexmedetomidine alone in search of an ideal sedation regime, which would achieve better intubating conditions, hemodynamic stability, and sedation for awake fiberoptic nasotracheal intubation.

Materials and Methods:

A total of 60 adult patients of age group 18-60 years with American Society of Anesthesiologists I and II posted for elective surgery under general anesthesia were randomly divided into two groups of 30 each in this prospective randomized controlled double-blinded study. Groups I and II patients received a bolus dose of dexmedetomidine at 1 mcg/kg over 10 min followed by a continuous infusion of dexmedetomidine at 0.5 mcg/kg/h. Upon completion of the dexmedetomidine bolus, Group I patients received 15 mg of ketamine and an infusion of ketamine at 20 mg/h followed by awake fiberoptic nasotracheal intubation, while Group II patients upon completion of dexmedetomidine bolus received plain normal saline instead of ketamine. Hemodynamic variables like heart rate (HR) and mean arterial pressure (MAP), oxygen saturation, electrocardiogram changes, sedation score (modified Observer assessment of alertness/sedation score), intubation score (vocal cord movement and coughing), grimace score, time taken for intubation, amount of lignocaine used were noted during the course of study. Patient satisfaction score and level of recall were assessed during the postoperative visit the next day.

Results:

Group I patients maintained a stable HR and MAP (<10% fall when compared with the baseline value). Sedation score (3.47 vs. 3.93) and patient satisfaction score were better in Group I patients. There was no significant difference in intubation scores, grimace scores, oxygen saturation and level of recall when compared between the two groups (P > 0.05).

Conclusion:

The use of dexmedetomidine plus ketamine combination in awake fiberoptic nasotracheal intubation provided better hemodynamic stability and sedation than dexmedetomidine alone.

A randomized controlled trial of the effect of preoperative dexmedetomidine on the half maximal effective concentration of propofol for successful i-gel insertion without muscle relaxants

BACKGROUND

Dexmedetomidine is a useful anesthetic adjuvant for general anesthesia. We determined whether preoperative dexmedetomidine administration could reduce the half maximal effective concentration (EC50) of propofol for successful i-gel insertion without muscle relaxants.

METHODS

Thirty-seven patients were randomly allocated to one of two groups. In the dexmedetomidine group (n = 19), dexmedetomidine (1 µg/kg) was loaded for 10 min preoperatively. In the control group (n = 20), the same volume of 0.9% normal saline was administered in the same manner. The EC50 of propofol for successful i-gel insertion was determined using Dixon's up-and-down method. The EC50 of propofol was calculated as the midpoint concentration after at least six crossover points had been obtained. For successful i-gel insertion, all of the following four factors were required—(1) no major movement of the body within 1 min of insertion, (2) no significant resistance to mouth opening, (3) cough ≤2, and (4) visible square wave capnogram without air leakage at a peak airway pressure of <10 cmH2O. Mean blood pressure (MBP) and heart rate (HR) were monitored during the peri-insertion period of i-gel.

RESULTS

The EC50 of propofol for successful i-gel insertion was 3.18 μg/mL in the dexmedetomidine group and 6.75 μg/mL in the control group (p < 0.001). The incidence of hypotension (MBP <80% of the baseline) during the peri-insertion period of i-gel was higher in the control group (p = 0.001), whereas the incidence of bradycardia (HR <80% of the baseline) was higher in the dexmedetomidine group (p = 0.001).

CONCLUSIONS

Preoperative dexmedetomidine reduced the EC50 of propofol for successful i-gel insertion without muscle relaxants.

The comparison of monitored anesthesia care with dexmedetomidine and spinal anesthesia during varicose vein surgery

Purpose

The purpose of this study was to investigate the effectiveness and safety of monitored anesthesia care (MAC) using dexmedetomidine for its sedative and analgesic effect during varicose vein surgery.

Methods

Forty-two patients, who underwent varicose vein surgery, were divided into the MAC group (n = 20) or the spinal anesthesia group (n = 22) for randomized clinical trial. In the MAC group, dexmedetomidine was administered by a loading dose of 1 µg/kg for 10 minutes, followed by a maintenance infusion of 0.2-1.0 µg/kg/hr. Ketamine was used for intermittent injection. In the spinal anesthesia group, midazolam was used for sedation. Intraoperative vital signs, the number of adverse events, and the satisfaction of patients and surgeons concerning the anesthetic condition were compared between the two groups.

Results

Systolic blood pressure was intraoperatively significantly different over time between the two groups. The groups had statistical differences in the change in heart rate with regard to time. In the postanesthetic care unit, patients and surgeons in the MAC group had a lower satisfaction score, compared to patients and surgeons in the spinal anesthesia group. However, in the recovery period, patients had a positive perception concerning MAC anesthesia. In addition, without significant adverse events, the MAC group had a shorter time to possible ambulation, which indicated an early recovery.

Conclusion

We believe that MAC using dexmedetomidine in combination with ketamine may be an alternative anesthetic technique for varicose vein surgery with regard to a patient's preference and medical condition.

Anesthesia for tracheostomy for huge maxillofacial tumor

Providing sedation for patients with compromised upper airway is challenging. A 19-year-old female patient with huge maxillofacial tumor invading the whole pharynx scheduled for elective tracheostomy under local anesthesia due to compromised airway. The patient had gastrostomy tube for feeding. Venous cannulation was totally refused by the patient after repeated trials for exhausted sclerosed veins. Pre-operative mixture of dexmedetomidine with ketamine was administered through the gastrostomy tube with eutectic mixture of local anesthetics cream application over the planned tracheostomy site. The patient was sedated with eye opening to command. Local infiltration followed by tracheostomy was performed without patient complaints or recall of operative events.

Dexmedetomidine

Objective. To provide a general descriptive account and review of the literature regarding the use of dexmedetomidine for sedation during fiberoptic bronchscopic (FOB) intubation. Data Source. A computerized bibliographic search of the literature regarding dexmedetomidine for FOB intubation. Main Results. Several anecdotal reports describe the use of dexmedetomidine to provide sedation during FOB intubation. Additionally, 7 prospective trials were identified. These prospective trials demonstrate the efficacy of dexmedetomidine in providing sedation during FOB intubation of the airway. In a placebo-controlled trial with midazolam used as the rescue medication, dexmedetomidine decreased the need for rescue midazolam and the combination of the 2 agents was better than midazolam alone. When compared with propofol, there were fewer airway and respiratory issues as well as improved patient comfort with dexmedetomidine. Although dexmedetomidine was found to be better than fentanyl, there was a higher incidence of adverse hemodynamic effects. Although dexmedetomidine was inferior to remifentanil, the study used a lower loading dose of dexmedetomidine than other studies (0.4 vs 1.0 µg/kg). Despite its efficacy, adverse hemodynamic effects were noted. In many cases, the incidence was higher with dexmedetomidine than the comparator agent. In all reported cases, these were corrected with the administration of atropine, a vasoactive medication (phenylephrine or ephedrine), and/or fluid. Conclusions. The present literature clearly reports the advantage of using dexmedetomidine to decrease the risk of adverse respiratory effects, including airway obstruction. However, there remain unanswered questions about dexmedetomidine for sedation during FOB intubation of the airway including dosing regimens for both the bolus and infusion, techniques to limit the potential for adverse hemodynamic effects, and whether it should be the sole agent or used in combination with another agent.

A randomised study of intranasal dexmedetomidine and oral ketamine for premedication in children

We studied the effects of intranasal dexmedetomidine combined with oral ketamine for premedication in children. One hundred and sixty children aged between 2 and 6 years were randomly allocated to one of four groups: 1 μg.kg(-1) intranasal dexmedetomidine with 3 mg.kg(-1) oral ketamine (Group 1); 1 μg.kg(-1) intranasal dexmedetomidine with 5 mg.kg(-1) oral ketamine (Group 2); 2 μg.kg(-1) intranasal dexmedetomidine with 3 mg.kg(-1) oral ketamine (Group 3); and 2 μg.kg(-1) intranasal dexmedetomidine with 5 mg.kg(-1) oral ketamine (Group 4). Sedation levels 10, 20 and 30 min after premedication were evaluated using a 5-point sedation scale. A 4-point emotional state score was used to evaluate patients when they were separated from their parents and their response to intravenous cannulation or facemask application. Approximately 90% of patients readily accepted premedication and onset times of acceptable sedation were similar in all four groups. Patients in Group 4 were significantly more sedated than those in Group 1 after 30 min (p = 0.036). A significantly higher proportion of patients in Group 3 (84%) and Group 4 (87%) accepted intravenous cannulation compared with those in Group 1 (40%) and Group 2 (54%) (p = 0.001). We conclude that the administration of 2 μg.kg(-1) intranasal dexmedetomidine and 3 mg.kg(-1) oral ketamine was the optimal combination, with children being easily separated from their parent, accepting intravenous cannulation and without causing excessive side-effects or postoperative complications.

Conscious sedation for awake fibreoptic intubation: a review of the literature

PURPOSE

Awake fibreoptic intubation (AFOI) is the gold standard of management of the predicted difficult airway. Sedation is frequently used to make the process more tolerable to patients. It is not always easy to strike a balance between patient comfort and good intubating conditions on the one hand and maintaining ventilation and a patent airway on the other. In the last 30 years, many drugs and drug combinations have been described, but there is very little in the literature to help guide the practitioner to choose between them. The objective of this article is to discuss the evidence supporting the use of the agents described with regard to their efficacy, recommended doses and techniques, and limitations to their use for AFOI.

SOURCE

Publication databases were searched for articles published from 1996 to 2012 relating to sedation for AFOI.

PRINCIPLE FINDINGS

Benzodiazepines, propofol, opioids, alpha2-adrenoceptor agonists, and ketamine are the main classes of drugs that have been described to facilitate AFOI. Drugs that are most suitable have a combination of both anxiolytic and analgesic properties. The ideal choice of drug may vary depending on the patient and the indication for AFOI.

CONCLUSION

There is good evidence to support the use of two drugs in particular, remifentanil and dexmedetomidine. Each has certain unique characteristics that make them an attractive choice for an AFOI.

Nasotracheal fiberoptic intubation: patient comfort, intubating conditions and hemodynamic stability during conscious sedation with different doses of dexmedetomidine

The study aims to evaluate the efficacy of two doses of dexmedetomidine for sedation during awake fiberoptic intubation (AFOI). The study was designed in a prospective, randomized, double-blinded manner and carried out in an academic medical university. Forty young co-operative patients aged 15–45 years of either sex belonging to ASA class I-II, planned for elective maxillo-facial surgery formed the study group. All patients received midazolam 0.05 mg/kg, glycopyrrolate 0.2 mg, ondansetron 4 mg, and ranitidine 50 mg IV 15 min before as premedication, oxygen by nasal cannula, and topical local anesthetics to the airway. Patients were randomly assigned to one of the groups; dexmedetomedine 1 μg/kg IV (Group L), or dexmedetomidine 1.5 μg/kg IV (Group H). Observer’s Assessment of Alertness/Sedation (OAA/S) was assessed. Primary outcome measurements were: HR, MAP, SpO₂ and EtCO₂ and secondary outcome measurements were: intubation scores by vocal cord movement, coughing and limb movement, fiberoptic intubation comfort score, nasotracheal intubation score and airway obstruction score. On the first post-operative day, recall, level of discomfort during fiberoptic intubation, adverse events and satisfaction score were also assessed. There were no significant hemodynamic differences between the two groups. OAA/S was significantly better with dexmedetomidine 1.5 μg/kg (p < 0.05) and patients were significantly calmer, more cooperative and satisfied during awake fiberoptic intubation with dexmedetomidine 1.5 μg/kg with fewer transient adverse effects. Dexmedetomidine 1.5 μg/kg proved to be more effective for sedation for awake fiberoptic intubation.

Ketodex, a combination of dexmedetomidine and ketamine for upper gastrointestinal endoscopy in children: a preliminary report

A combination of dexmedetomidine and ketamine for upper gastrointestinal endoscopies (UGIE) was studied in 46 children aged 2-12 years over a 6-month period. Dexmedetomidine 1 μg/kg and ketamine 2 mg/kg were given as a bolus over 5 min. Heart rate (HR), mean arterial pressure (MAP), oxygen saturation (SpO2), and sedation scores were noted before induction as baseline and then every 5 min until recovery. The duration and ease of the procedure, time to recovery, and adverse effects, if any, were also recorded. UGIE could be performed with ease in 41 of the 46 cases. The HR, MAP, and SpO2 did not change significantly from the baseline. No airway intervention was required in any patient. There was no laryngospasm or shivering in any of the children, and one, four, and 11 children had hiccup, vomiting, and increased salivation, respectively. The Pediatric Anesthesia Emergence Delirium score was <4 in all except for two cases. The results of this case series show that this drug combination not only promises to be clinically effective but also safe for UGIE in children. Further randomized controlled trials with standard sedation protocols will be required to draw definite conclusions.

Dexmedetomidine versus remifentanil sedation during awake fiberoptic nasotracheal intubation: a double-blinded randomized controlled trial

BACKGROUND

Awake fiberoptic nasotracheal intubation is usually performed in patients with an anticipated difficult airway. This study compares dexmedetomidine and remifentanil for conscious sedation during fiberoptic intubation.

METHODS

Forty patients undergoing elective awake fiberoptic nasotracheal intubation were allocated randomly to receive either dexmedetomidine (n = 20) or remifentanil (n = 20). Primary outcome measures were endoscopy, intubation, and post-intubation conditions as scored by the attending anesthesiologist. Other parameters included the time taken to achieve the desired level of sedation, endoscopy time, intubation time, and hemodynamic changes during the procedure. An interview was conducted 24 h after surgery to evaluate patients' recall of and satisfaction with the procedure.

RESULTS

The median [interquartile range] endoscopy score (graded 0-5) in the dexmedetomidine group (2 [1-2]) was significantly better than in patients who received remifentanil (3 [2-3]; p < 0.01). Recall of intubation was significantly lower in the dexmedetomidine group (p = 0.027). Dexmedetomidine provided better patient satisfaction than remifentanil (2 [1-2] and 2 [2-3], respectively; p = 0.022). Patients in the dexmedetomidine group had fewer heart rate responses during endoscopy and intubation as compared to the remifentanil group (p < 0.001 and p = 0.004, respectively). Peripheral oxygen saturation was less in the remifentanil group during endoscopy (p = 0.003). There were no significant differences in intubation and post-intubation conditions.

CONCLUSIONS

Both dexmedetomidine and remifentanil were effective as sedatives in patients undergoing awake fiberoptic nasotracheal intubation. Compared with remifentanil, dexmedetomidine offered better endoscopy scores, lower recall of intubation, and greater patient satisfaction, with minor hemodynamic side effects.

Does dexmedetomidine affect intraoperative blood loss and clotting tests in pediatric adenotonsillectomy patients?

BACKGROUND

We hypothesize that dexmedetomidine (DEX), a selective α(2) adrenergic receptor agonist, may affect the intraoperative blood loss and clotting tests such as prothrombin time, activated partial thromboplastin time, and international normalized ratio in children undergoing adenotonsillectomy (ADT).

METHODS

Sixty patients scheduled for elective ADT under general anesthesia. The patients were randomly assigned to receive either DEX 0.5 μg/kg (group D) or placebo bolus (group C) with a total volume of 10 mL, 10 min before the induction of anesthesia. Mean arterial pressure (MAP), heart rate, blood loss, preoperatively and immediately after awakening clotting tests, agitation, sedation, visual analog scale, and analgesic requirement, were assessed and recorded.

RESULTS

The postoperative hemoglobin was significantly lower than the preoperative value in both groups (P < 0.05). The postoperative agitation scale and analgesic requirement and visual analog scale at the 15th min were significantly lower in group D than those in group C (P < 0.05). Total blood loss and postoperative sedation score in group D was significantly higher than that in group C (P < 0.05). The postoperative prothrombin time, activated partial thromboplastin time, international normalized ratio tests between the groups, additionally pre-postoperative MAP, heart rate, and clotting tests were similar in each group.

CONCLUSIONS

The premedication with DEX 0.5 μg/kg decreased postoperative agitation, pain, and analgesic requirement without significant change in the clotting tests and MAP but increased bleeding slightly during ADT.

Maternal and preterm fetal sheep responses to dexmedetomidine

BACKGROUND

The α(2) adrenergic receptor agonist dexmedetomidine has some unique pharmacologic properties that could benefit pregnant patients (and their fetuses) when they require sedation, analgesia, and/or anesthesia during pregnancy. The purpose of the present study was to delineate maternal and fetal responses to an intravenous infusion of dexmedetomidine.

METHODS

This study was conducted on surgically-recovered preterm sheep instrumented for physiologic recording and blood sampling. Maternal and fetal cardiovascular and blood gas parameters and fetal cerebral oxygenation levels were recorded before, during, and after 3h of dexmedetomidine infusion to the ewe at a rate of 1 μg/kg/h.

RESULTS

Drug infusion produced overt sedation but no apparent respiratory depression as evidenced by stable maternal arterial blood gases; fetal blood gases were also stable. The one blood parameter to change was serum glucose, By the end of the 3-h infusion, glucose increased from 49±10 to 104±33mg/dL in the ewe and from 22±3 to 48±16mg/dL in the fetus; it declined post-drug exposure but remained elevated compared to the starting levels (maternal, 63±12mg/dL, P=0.0497; and fetal, 24±4mg/dL, P=0.012). With respect to cardiovascular status, dexmedetomidine produced a decrease in maternal blood pressure and heart rate with fluctuations in uterine blood flow but had no discernable effect on fetal heart rate or mean arterial pressure. Likewise, maternal drug infusion had no effect on fetal cerebral oxygenation, as measured by in utero near-infrared spectroscopy.

CONCLUSIONS

Using a clinically-relevant dosing regimen, intravenous infusion of dexmedetomidine produced significant maternal sedation without altering fetal physiologic status. Results from this initial acute assessment support the conduct of further studies to determine if dexmedetomidine has clinical utility for sedation and pain control during pregnancy.

Dexmedetomidine versus Remifentanil for Sedation during Awake Fiberoptic Intubation

This study compared remifentanil and dexmedetomidine as awake fiberoptic intubation (AFOI) anesthetics. Thirty-four adult ASA I-III patients were enrolled in a double-blinded randomized pilot study to receive remifentanil (REM) or dexmedetomidine (DEX) for sedation during AFOI (nasal and oral). Thirty patients completed the study and received 2 mg midazolam IV and topical anesthesia. The REM group received a loading dose of 0.75 mcg/kg followed by an infusion of 0.075 mcg/kg/min. The DEX group received a loading dose of 0.4 mcg/kg followed by an infusion of 0.7 mcg/kg/hr. Time to sedation, number of intubation attempts, Ramsay sedation scale (RSS) score, bispectral index (BIS), and memory recall were recorded. All thirty patients were successfully intubated by AFOI (22 oral intubations/8 nasal). First attempt success rate with AFOI was higher in the REM group than the DEX group, 72% and 38% (P = 0.02), respectively. The DEX group took longer to attain RSS of ≥3 and to achieve BIS <80, as compared to the REM group. Postloading dose verbal recall was poorer in the DEX group. Dexmedetomidine seems a useful adjunct for patients undergoing AFOI but is dependent on dosage and time. Further studies in the use of dexmedetomidine for AFOI are warranted.

Apoptotic neurodegeneration and spatial memory are not affected by sedative and anaesthetics doses of ketamine/medetomidine combinations in adult mice

BACKGROUND

Ketamine is increasingly popular in clinical practice and its combination with α(2)-agonists can provide good anaesthetic stability. Little is known about the effects of this combination in the brain. Therefore, we investigated the effects of different concentrations of ketamine combined with medetomidine on cognition and its potential apoptotic neurodegenerative effect in adult mice.

METHODS

Seventy-eight C57BL/6 adult mice were divided into six different groups (saline solution, 1 mg kg(-1) medetomidine, 25 mg kg(-1) ketamine+1 mg kg(-1) medetomidine, 75 mg kg(-1) ketamine+1 mg kg(-1) medetomidine, 25 mg kg(-1) ketamine, and 75 mg kg(-1) ketamine). Eight animals per group were tested in the T-maze, vertical pole, and open-field test. Five animals per group were used for histopathological [haematoxylin and eosin (HE) staining] and immunohistochemical analyses [caspase-3 activation and expression of neurotrophin brain-derived neurotrophic factor (BDNF)]. Cells showing clear HE staining and positive immunoreactions for caspase-3 and BDNF in the retrosplenial cortex, visual cortex, pyramidal cell layer of the cornu Ammonis 1 and cornu Ammonis 3 areas of the hippocampus, and in the granular layer of the dentate gyrus were counted.

RESULTS

There were no differences between groups regarding the number of dead cells and cells showing positive immunoreactions in the different areas of the brain studied. Similarly, no differences were detected in the number of trials to complete the T-maze task. Nevertheless, α(2)-agonist decreased hyperlocomotion caused by ketamine in the open field.

CONCLUSIONS

Neither apoptotic neurodegeneration nor alterations in spatial memory were observed with different concentrations of ketamine combined with medetomidine in adult mice.

Sudden Tracheal Collapse during EGD and Subsequent Anesthetic Management with Dexmedetomidine-Ketamine in a Patient with Achalasia and Tracheomalacia

We present a patient who experienced airway obstruction during an elective esophagogastroduodenoscopy (EGD) under anesthesia secondary to previously undiagnosed tracheomalacia. Physiology of airway obstruction with forced breathing maneuvers is discussed along with the potential advantages of dexmedetomidine-ketamine sedation for management of patients with achalasia undergoing outpatient endoscopic procedures.

Subcutaneous dissociative conscious sedation (sDCS) an alternative method for airway regional blocks: a new approach

BACKGROUND

Predicted difficult airway is a definite indication for awake intubation and spontaneous ventilation. Airway regional blocks which are commonly used to facilitate awake intubation are sometimes impossible or forbidden. On the other hand deep sedation could be life threatening in the case of compromised airway.The aim of this study is evaluating "Subcutaneous Dissociative Conscious Sedation" (sDCS) as an alternative method to airway regional blocks for awake intubation.

METHODS

In this prospective, non-randomized study, 30 patients with predicted difficult airway (laryngeal tumors), who were scheduled for direct laryngoscopic biopsy (DLB), underwent "Subcutaneous Dissociative Conscious Sedation" (sDCS) exerted by intravenous fentanyl 3-4ug/kg and subcutaneous ketamine 0.6-0.7 mg/kg. The tongue and pharynx were anesthetized with lidocaine spray (4%). 10 minutes after a subcutaneous injection of ketamine direct laryngoscopy was performed. Extra doses of fentanyl 50-100 ug were administered if the patient wasn't cooperative enough for laryngoscopy.Patients were evaluated for hemodynamic stability (heart rate and blood pressure), oxygen saturation (Spo2), patient cooperation (obedient to open the mouth for laryngoscopy and the number of tries for laryngoscopy), patient comfort (remaining moveless), hallucination, nystagmus and salivation (need for aspiration before laryngoscopy).

RESULTS

Direct laryngoscopy was performed successfully in all patients. One patient needed extra fentanyl and then laryngoscopy was performed successfully on the second try. All patients were cooperative enough during laryngoscopy. Hemodynamic changes more than 20% occurred in just one patient. Oxygen desaturation (spo2< 90%) didn't occur in any patient.

CONCLUSIONS

Subcutaneous Dissociative Conscious Sedation (sDCS) as a new approach to airway is an acceptable and safe method for awake intubation and it can be suggested as a noninvasive substitute of low complication rate for regional airway blocks.

REGISTRATION ID IN IRCT

IRCT201012075333N1.

Dexmedetomidine sedation for awake fiberoptic intubation of patients with difficult airways due to severe odontogenic cervicofacial infections

PURPOSE

Odontogenic infections present challenging airway scenarios to surgeons and anesthesiologists. Among specialists, there is controversy over airway management for those patients with airways made difficult by trismus and swelling with anatomic impingement and derangement. Awake fiberoptic intubation has achieved favor in the oral and maxillofacial surgery and anesthesiology communities for management of such difficult airways, but patient comfort and anxiety management with traditional agents may prove hazardous because of potential suppression of protective mechanisms and respiratory depression.

PATIENTS AND METHODS

Three cases are presented showing the utility and safety of the use of dexmedetomidine sedation for presurgical airway instrumentation and insertion in patients with challenging airways because of severe cervicofacial odontogenic infections.

RESULTS

Dexmedetomidine administration provided safe and effective sedation and anxiolysis for awake fiberoptic airway instrumentation and airway insertion in patients presenting with severe cervicofacial infections with difficult airways because of anatomic obstruction.

CONCLUSIONS

Dexmedetomidine sedation is advocated for use in awake fiberoptic intubation of patients with cervicofacial infections and difficult airways because of its ability to provide sedation, analgesia, reversible anterograde amnesia, and anxiolysis without impairment of protective reflexes, respiratory depression, or hemodynamic compromise. One of the most significant challenges facing oral and maxillofacial surgeons is the difficult airway. Anatomically compromised airways present unique clinically daunting situations to both surgeon and anesthesiologist, who are both charged with the provision of safe, effective preoperative, intraoperative, and postoperative airway management. Among these conditions, odontogenic infections and patients with head and neck trauma, temporomandibular disorders, orofacial tumors, and severe craniofacial anomalies present for surgical treatment by the oral and maxillofacial surgeon.

Dexmedetomidine and ketamine for sedation during spinal anesthesia in children

STUDY OBJECTIVE

To evaluate the combination of dexmedetomidine and ketamine for sedation during lumbar puncture and sedation for spinal anesthesia in children.

DESIGN

Retrospective analysis of quality assurance data sheets and anesthetic records.

SETTING

Developing countries with the humanitarian group, Kids First.

PATIENTS

12 infants and children, ranging in age from two to 9 years.

INTERVENTIONS

A bolus dose of ketamine (two mg/kg) and dexmedetomidine (one μg/kg) was given over three minutes followed by a continuous infusion of dexmedetomidine (two μg/kg/hr for the first 30 min, followed by one μg/kg/hr for the duration of the case). Supplemental analgesia/sedation was provided by ketamine (0.5 mg/kg) as needed.

MEASUREMENTS

The need for supplemental ketamine, the ability to complete the procedure, and heart rate (HR), blood pressure, end-tidal carbon dioxide (ETCO(2)), and oxygen saturation values were recorded.

MAIN RESULTS

Effective sedation for lumbar puncture and performance of spinal anesthesia were achieved in all patients. One patient required a supplemental dose of ketamine (0.5 mg/kg). Following the bolus dose of ketamine and dexmedetomidine, HR increased by 11 ± 4 bpm. The greatest HR increase was 20 bpm. No patient had a HR increase ≥ 20% from baseline. The HR decrease was ≤ 30 bpm in 10 of the 12 patients, and the greatest HR decrease was 58 bpm. Systolic blood pressure (SBP) increased from baseline by 10 ± 3 mmHg after administration of the bolus dose of ketamine and dexmedetomidine. During the subsequent dexmedetomidine infusion, SBP decreased by 11 ± 9 mmHg. No patient's respiratory rate decreased to less than 10 breaths/min or increased above 24 breaths/min during the procedural sedation. The highest ETCO(2) was 45 ± 2 mmHg (P < 0.0001). Oxygen saturation remained ≥ 95% during the procedure in all patients.

CONCLUSION

A combination of ketamine and dexmedetomidine provides effective sedation during spinal anesthesia in infants and children, with limited effects on cardiovascular and ventilatory function.

Anesthetic considerations and surgical caveats for awake airway surgery

The evolution of novel techniques for the treatment of laryngeal pathology has led to a significant expansion of the role of diagnostic assessment and the range of laryngeal procedures performed. These procedures typically benefit from an anesthetic approach that diverges from a standard general endotracheal or laryngeal mask airway-based inhalational anesthetic. The shared airway, need for intraoperative assessment of vocal cord function, risk of airway fire, and desire for rapid emergence and discharge are all important factors. In this article the authors undertake a collaborative anesthesia-surgical discussion of anesthetic management for airway procedures that are optimally performed with a spontaneously breathing, cooperative patient. An overview of pharmacologic approaches to airway anesthesia and cooperative sedation, followed by a discussion on the surgical requirements and anesthetic goals of commonly performed procedures, are presented.

Management of a tumor in the distal trachea while maintaining spontaneous ventilation

A 50-year-old man with carcinoma of the trachea presented for debulking. Due to the distal location of the tumor, a tracheostomy was not feasible. We were asked to provide general anesthesia but to maintain spontaneous ventilation. Sedation was provided with dexmedetomidine 0.7 μg/kg per hour. Following induction with ketamine 2 mg/kg, the trachea was sprayed with 5 ml of 4% lidocaine and, with assistance from the surgeon, a Cook™ Airway Exchange catheter was placed with the distal end just beyond the tumor. We then connected the proximal end to a manual jet ventilator to provide oxygen supplementation and, if necessary, positive-pressure ventilation. Subsequently, the surgeons were able to completely debulk the tumor and examine the airway down to the carina. Spontaneous ventilation was maintained throughout the case, with additional boluses of ketamine as necessary. The patient woke up after the procedure and had no delirium, nightmares, or recall. Dexmedetomidine worked synergistically with ketamine by preventing hypertension, hypersecretion, and postoperative delirium that is often seen when using ketamine alone. The successful use of ketamine and dexmedetomidine in this case demonstrates that this method may be applicable to other clinical situations where deep sedation and maintenance of spontaneous ventilation is required.

Update on dexmedetomidine: use in nonintubated patients requiring sedation for surgical procedures

Dexmedetomidine was introduced two decades ago as a sedative and supplement to sedation in the intensive care unit for patients whose trachea was intubated. However, since that time dexmedetomidine has been commonly used as a sedative and hypnotic for patients undergoing procedures without the need for tracheal intubation. This review focuses on the application of dexmedetomidine as a sedative and/or total anesthetic in patients undergoing procedures without the need for tracheal intubation. Dexmedetomidine was used for sedation in monitored anesthesia care (MAC), airway procedures including fiberoptic bronchoscopy, dental procedures, ophthalmological procedures, head and neck procedures, neurosurgery, and vascular surgery. Additionally, dexmedetomidine was used for the sedation of pediatric patients undergoing different type of procedures such as cardiac catheterization and magnetic resonance imaging. Dexmedetomidine loading dose ranged from 0.5 to 5 μg kg⁻¹, and infusion dose ranged from 0.2 to 10 μg kg⁻¹ h⁻¹. Dexmedetomidine was administered in conjunction with local anesthesia and/or other sedatives. Ketamine was administered with dexmedetomidine and opposed its bradycardiac effects. Dexmedetomidine may by useful in patients needing sedation without tracheal intubation. The literature suggests potential use of dexmedetomidine solely or as an adjunctive agent to other sedation agents. Dexmedetomidine was especially useful when spontaneous breathing was essential such as in procedures on the airway, or when sudden awakening from sedation was required such as for cooperative clinical examination during craniotomies.

The effectiveness of dexmedetomidine infusion for sedating oral cancer patients undergoing awake fibreoptic nasal intubation

BACKGROUND AND OBJECTIVE

Dexmedetomidine is characterized with effects of sedation, analgesia, amnesia and lack of respiratory depression. Hence, it should be suitable for awake fibreoptic intubation (AFOI).

METHODS

We enrolled 30 oral cancer patients with limited mouth openings who were undergoing AFOI for elective surgery. Patients were randomly allocated into two groups; the Dex group (n = 16) that received dexmedetomidine (1.0 microg kg(-1)) infusion and the Control group (n = 14) that received fentanyl (1.0 microg kg(-1)) infusion. Main outcomes were evaluated by grading scores presenting conditions for nasal intubation and postintubation. Other analysed parameters included airway obstruction, haemodynamic changes, consumption time for intubation, amnesia level and satisfaction.

RESULTS

Intubation score (1-5) representing condition for nasal intubation was significantly better in the Dex group [2(1-3)] than in the Control group [3(2-5)] (P = 0.001). Postintubation score (1-3) representing tolerance to intubation also showed more favourable results in the Dex group [1(1-3)] than in the Control group [2(2-3)] (P = 0.002). The Dex group showed significantly reduced haemodynamic response to intubation than the Control group. Incidence requiring temporary haemodynamic support was higher in the Dex group but not of significance. Both levels of amnesia and satisfaction score were significant in the Dex group. Other analysed parameters such as consumption time for intubation, airway obstruction score and postoperative adverse events did not differ significantly.

CONCLUSION

Combination of dexmedetomidine loading with topical anaesthesia provides significant benefit for AFOI in intubation condition, patient tolerance, haemodynamic response, amnesia and satisfaction. Dexmedetomidine is effective for AFOI in anticipated difficult airway with only minor and temporary haemodynamic adverse effects.

Pain relief during dressing changes of major adult burns: ideal analgesic combination with ketamine

Pain management during burn dressing changes is a critical part of treatment in acute burn injuries. Although several treatment options have been suggested, it is still a challenge in a clinical setting. This study is aimed at finding out an ideal analgesic, sedative and/or anxiolytic combination that would minimise the unwanted effects of ketamine. A total of 24 patients, with burns up to 20-50% of total body surface area (TBSA), were included in the study and randomly divided into three groups. In group I, 2 mg kg(-1) ketamine was administered. In group II, 1 mg kg(-1) tramadol was administered and 30 min later, 1 microg kg(-1) dexmedetomidine and 2 mg kg(-1) ketamine was administered. In group III, 1 mg kg(-1) tramadol was applied and 30 min later, 0.05 mg kg(-1) midazolam and 2 mg kg(-1) ketamine was administered. The evaluation was performed with cardiopulmonary monitoring, sedation and visual analogue pain scores and overall patient satisfaction. Any adverse effects of ketamine were recorded. The results showed that group II had better outcomes with respect to pain management during dressing changes. As a conclusion, the use of the combination of ketamine, tramadol and dexmedetomidine was found to be a good treatment option for the prevention of the procedural pain suffered by adult patients during dressing changes.

Dexmedetomidine for awake fiberoptic intubation in a parturient with spinal muscular atrophy type III for cesarean delivery

Spinal muscular atrophy in pregnancy is rare and poses multiple problems for the anesthesiologist. The effects of dexmedetomidine on a parturient with spinal muscular atrophy have not previously been reported. There are also no in vivo data on placental transfer of dexmedetomidine and its effects on a human neonate. We report the hemodynamic, respiratory and sedative effects of dexmedetomidine on a parturient and neonate when used for awake fiberoptic intubation before cesarean section. A 35-year-old, gravida 4 para 0 aborta 3, 41-kg parturient at 35 weeks of gestation with spinal muscular atrophy presented for cesarean section. Dexmedetomidine was administered intravenously, total dose 1.84 microg/kg over 38 minutes, followed by fiberoptic endotracheal intubation. Dexmedetomidine was then discontinued and general anesthesia was induced. The baby was delivered 68 minutes after the dexmedetomidine infusion was discontinued at which time blood samples were obtained for measurement of dexmedetomidine. During administration of dexmedetomidine, maternal heart rate, blood pressure and oxygen saturation remained stable. Apgar scores at 1 and 5 min were 6 and 8. The fetal concentration of dexmedetomidine (540 pg/mL) indicates significant placental transfer, but significant adverse neonatal effects were not observed. Dexmedetomidine alone provided adequate sedation for awake intubation without respiratory compromise in this patient.

Dexmedetomidine and ketamine for fiberoptic intubation in a child with severe mandibular hypoplasia

A 6-year-old girl with Treacher Collins syndrome presented for implantation of a hearing device. The patient was developmentally delayed and had severe micrognathia. After induction of anesthesia with dexmedetomidine and ketamine, the patient tolerated the introduction of a flexible fiberoptic bronchoscope without any change in respiration, and intubation was achieved easily.

Clinical efficacy of dexmedetomidine alone is less than propofol for conscious sedation during ERCP

BACKGROUND

Propofol is an accepted method of sedation for an ERCP and generally achieves deep sedation rather than conscious sedation, and dexmedetomidine has sedative properties of equivalent efficacy.

OBJECTIVE

To examine the hypothesis that dexmedetomidine is as effective as propofol combined with fentanyl for providing conscious sedation during an ERCP.

DESIGN AND SETTING

Randomized, blind, double-dummy clinical trial.

PATIENTS

Twenty-six adults, American Society of Anesthesiologists status I to III, underwent an ERCP.

INTERVENTIONS

Patients were randomized to receive either propofol (n = 14) (target plasma concentration range 2-4 microg/mL) combined with fentanyl 1 microg/kg, or dexmedetomidine (n = 12) 1 microg/kg for 10 minutes, followed by 0.2 to 0.5 microg/kg/min. Additional sedatives were used if adequate sedation was not achieved at the maximum dose allowed.

MAIN OUTCOMES MEASUREMENTS

The sedation level was assessed by the Richmond alertness-sedation scale and the demand for additional sedatives. Furthermore, heart rate, blood pressure, oxygen saturation, and respiratory rate were continuously assessed.

RESULTS

The relative risk (RR) was 2.71 (95% CI, 1.31-5.61) and the number of patients that needed to be treated (NNT) was 1.85 (95% CI, 1.19-4.21) to observe one additional patient with drowsiness 15 minutes after sedation in the dexmedetomidine group. Also, the RR was 9.42 (95% CI, 1.41-62.80), and the NNT was 1.42 (95% CI, 1.0-2.29) to require additional analgesic. However, there was also a greater reduction in blood pressure, a lower heart rate, and greater sedation after the procedure.

CONCLUSIONS

Dexmedetomidine alone was not as effective as propofol combined with fentanyl for providing conscious sedation during an ERCP. Furthermore, dexmedetomidine was associated with greater hemodynamic instability and a prolonged recovery.

Dexmedetomidine as sole sedative for awake intubation in management of the critical airway

We report a series of successful awake fiberoptic intubations in patients with critical (unstable, difficult) airways using the alpha(2)-agonist, dexmedetomidine. Dexmedetomidine has several desirable pharmacologic properties, including sedation, anxiolysis, hypnosis, analgesia, amnesia, antisialagogue effects, and a unique respiratory-sparing effect. Dexmedetomidine appears to be a useful agent for sedation during awake fiberoptic intubation in difficult airway patients.