Monitored Anesthesia Care With a Combination of Ketamine and Dexmedetomidine During Cardiac Catheterization

Determination of optimal combined doses of oral midazolam and intranasal dexmedetomidine for use in pediatric magnetic resonance imaging

Background

Sedation is often required for infant and preschool children to obtain clear magnetic resonance imaging (MRI). This study was designed to determine the 95% effective dose (ED95) of oral midazolam (MID) and intranasal dexmedetomidine (DEX) in combination for sedation in pediatric MRI.

Methods

We have used a biased coin design up-and-down sequential methodology. Initially, 144 patients were split into two groups. A total of 72 patients were randomly assigned to determine the ED95 of DEX in combination with a fixed dose of 0.5 mg/kg MID, and 72 were given various doses of MID combined with a fixed dose of DEX at 1 µg/kg to determine the ED95 of MID. ED95 was calculated using isotonic regression. At last, the plan was to include 225 cases to test the sedation success rate of DEX combined with MID ED95 dose. Adverse events were recorded.

Results

The ED95 of DEX was 0.89 µg/kg (95% confidence interval (CI) 0.68 to 0.95) combined with a fixed dose of MID at 0.5 mg/kg. The ED95 of MID was 0.47 mg/kg (95% CI 0.30 to 0.50) combined with a fixed intranasal dose of 1 µg/kg DEX. Using 1 µg/kg DEX combined with 0.5 mg/kg MID, the sedation success rate was 95.1% in a verification group of 225 children.

Conclusions

This study reports relatively low ED95 doses of intranasal DEX and oral MID when DEX is determined with a fixed dose of MID and MID determined with a fixed dose of DEX. The combination provides efficient and safe sedation for young children for MRI scanning. Further validation is required.

Trial registration number

ChiCTR2300068611.

Association of ketamine use during procedural sedation with oxygen desaturation and healthcare utilisation: a multicentre retrospective hospital registry study

BACKGROUND

We investigated the effects of ketamine on desaturation and the risk of nursing home discharge in patients undergoing procedural sedation by anaesthetists.

METHODS

We included adult patients who underwent procedures under monitored anaesthetic care between 2005 and 2021 at two academic healthcare networks in the USA. The primary outcome was intraprocedural oxygen desaturation, defined as oxygen saturation <90% for ≥2 consecutive minutes. The co-primary outcome was a nursing home discharge.

RESULTS

Among 234,170 included patients undergoing procedural sedation, intraprocedural desaturation occurred in 5.6% of patients who received ketamine vs 5.2% of patients who did not receive ketamine (adjusted odds ratio [ORadj] 1.22, 95% confidence interval [CI] 1.15-1.29, P<0.001; adjusted absolute risk difference [ARDadj] 1%, 95% CI 0.7-1.3%, P<0.001). The effect was magnified by age >65 yr, smoking, or preprocedural ICU admission (P-for-interaction <0.001, ORadj 1.35, 95% CI 1.25-1.45, P<0.001; ARDadj 2%, 95% CI 1.56-2.49%, P<0.001), procedural risk factors (upper endoscopy of longer than 2 h; P-for-interaction <0.001, ORadj 2.91, 95% CI 1.85-4.58, P<0.001; ARDadj 16.2%, 95% CI 9.8-22.5%, P<0.001), and high ketamine dose (P-for-trend <0.001, ORadj 1.61, 95% CI, 1.43-1.81 for ketamine >0.5 mg kg-1). Concomitant opioid administration mitigated the risk (P-for-interaction <0.001). Ketamine was associated with higher odds of nursing home discharge (ORadj 1.11, 95% CI 1.02-1.21, P=0.012; ARDadj 0.25%, 95% CI 0.05-0.46%, P=0.014).

CONCLUSIONS

Ketamine use for procedural sedation was associated with an increased risk of oxygen desaturation and discharge to a nursing home. The effect was dose-dependent and magnified in subgroups of vulnerable patients.

Combination of high-flow nasal oxygen and ketamine/dexmedetomidine sedation for diagnostic catheterization in a child with pulmonary arterial hypertension: a case report

Pulmonary hypertension is associated with significant risk of perioperative life-threatening events. We present a case of a 12-year-old child with severe pulmonary arterial hypertension who successfully underwent diagnostic cardiac catheterization under ketamine and dexmedetomidine sedation with the support of high-flow nasal oxygen. Ketamine and dexmedetomidine are reported to have minimal effect on pulmonary vasculature in children with pulmonary hypertension and can be safely used in this population along with its lack of respiratory depression. Positive pressure generated by high-flow nasal oxygen improves upper airway patency, prevents micro-atelectasis, and is shown to improve the effectiveness of ventilation and oxygenation in patients under sedation breathing spontaneously. The presented strategy may contribute to enhancing the safety and effectiveness of procedural sedation for children with life-threatening pulmonary hypertension.

Asystole in 2 Pediatric Patients During Dexmedetomidine Infusion

INTRODUCTION

Bradycardia is a known side effect of dexmedetomidine. Reports of sinus pauses or asystole, however, are rare. We present 2 cases of pediatric patients who developed asystole on a dexmedetomidine infusion.

SUMMARY OF CASES

An 8-week-old male with RSV bronchiolitis and acute hypoxemic respiratory failure was started on dexmedetomidine for sedation at 0.2 mcg/kg/h with a maximum dose of 0.7mcg/kg/h. On Hospital day (HD) 4, on dexmedetomidine at 0.7 mcg/kg/h, he developed intermittent episodes of bradycardia with heart rates in the 60 s. Echocardiogram on HD 6 showed normal function. On HD 7, he began having periods of asystole lasting up to 6 seconds. Dexmedetomidine was discontinued, with the resolution of episodes of asystole after 6 hours. A 27-month-old male with a congenital left diaphragmatic hernia and pulmonary hypertension who had been weaned off sildenafil 6 months earlier underwent re-repair of left diaphragmatic hernia. Postoperatively he remained intubated and paralyzed. Dexmedetomidine was started at 0.3 mcg/kg/h for sedation, with a maximum dose of 1.2 mcg/kg/h. An echocardiogram on HD 3 showed good function with mild to moderate pulmonary hypertension. That evening, with dexmedetomidine at 1.1 mcg/kg/h, he developed a 15 second period of asystole requiring CPR. Dexmedetomidine was discontinued, and he was started on a midazolam infusion with no further episodes.

DISCUSSION

Both cases occurred in patients without cardiac conduction defects or on negative chronotropic or sympatholytic medications that have been associated with dexmedetomidine-induced asystole. We hypothesize that both episodes of asystole were due to increased patient-related vagal tone exacerbated by dexmedetomidine.

Comparative Study of Intranasal Dexmedetomidine Versus Intranasal Ketamine as Premedicant in Children

Background: Pre-operative anxiety in children not only makes induction difficult but it is also associated with an increase in the requirement of analgesics, the incidence of post-operative nausea and vomiting (PONV), emergence delirium (ED), and postoperative maladaptive behavioral changes. It can be reduced effectively by pharmacological interventions. In a quest to find the ideal premedicant and non-invasive way of its administration, we decided to compare intranasal (IN) dexmedetomidine with IN ketamine as a premedicant in pediatric patients.

Aims and objectives: To compare sedation score, mask acceptance score (MAS) during induction, the incidence of ED, and other adverse events in both groups.

Material and methods: Some 60 children, between 1 and 8 years of age of either sex undergoing surgical procedures were included in this study and randomly divided into two groups (Group D and Group K). Thirty minutes prior to induction of anesthesia, patients of Group D received dexmedetomidine 1 mcg kg^-1 in 1 mL of 0.9% saline intranasally and patients of Group K received ketamine 5 mg kg^-1 in 1 mL of 0.9% saline intranasally through calibrated dropper (0.5 mL in each nostril) in a recumbent position. Incidences of sneezing or coughing after IN administration of study drugs were recorded. The subsequent sedation scores were assessed using MOASS at 15 min, then at 30 min following premedication at the time of parental separation. After shifting patients to operation theater inhalation induction was done. MAS at induction and any adverse effects were recorded.

Results: Children in Group K were found to be significantly more sedated at 30 min after administration of premedication and mask acceptance was also better (p value < 0.0001 with a confidence interval, CI=95%). But the incidence of ED and PONV was high.

Conclusion: Intranasal dexmedetomidine (1 mcg kg^-1) is clinically less effective as a premedicant in terms of sedation and mask acceptance in older children as compared to ketamine (5 mg kg^-1), but associated with fewer incidence of ED and PONV. We recommend the usage of IN dexmedetomidine in a higher dose (1.5-2 mcg kg^-1), through nebulization/atomizer for the desired level of sedation and mask acceptance.

The Effectiveness of Three Regimens of Sedation for Children Undergoing Magnetic Resonance Imaging: A Clinical Study

Background

Magnetic resonance imaging (MRI) under sedation requires faster recovery for early discharge and feeding resumption in children with neuropsychiatric disorders. The use of dexmedetomidine alone results in delayed recovery. Propofol, when used alone, can cause hypotension and respiratory depression. A new regimen for sedation was evaluated by exploiting the properties of these drugs, to allow faster recovery with minimal adverse events.

Materials and Methods

One hundred and fifty children aged 2-12 years requiring MRI were randomly allocated to these three groups. Group P (n = 50) received propofol bolus at 2 mg.kg-1 over 10 min followed by infusion at 100 μg.kg-1.min-1. Group D (n = 50) received dexmedetomidine bolus of 2 μg.kg-1 over 10 min followed by infusion at 1 μg.kg-1.h-1. Group PD (n = 50) received propofol bolus at 2 mg.kg-1 over 10 min followed by dexmedetomidine infusion at 1 μg.kg-1.h-1. Recovery characteristics were noted.

Results

Recovery following sedation in Group PD (15 ± 7.0 min) and Group P (17.35 ± 7.4 min) were comparable and significantly (P = 0.03) lesser than Group D (27.58 ± 8.09 min). Emergence delirium scores were significantly less in Group PD (5 ± 1.08) and Group D (5.6 ± 2.4), unlike scores in Group P (9 ± 2.43). About 79.5% (39/49) of children in Group P, 88.2% (45/51) of children in Group D, and 86% (43/50) of children in Group PD completed MRI without any movement. Seven (14.58%) in Group P, 2 (4%) in Group D, and 5 (10.20%) in Group PD required rescue sedation.

Conclusion

The regimen with propofol bolus and dexmedetomidine infusion provided adequate sedation and better recovery characteristics in children aged 2-12 years without systemic complications, as compared to the use of either agent alone.

Gastrointestinal endoscopy in children and adults: How do they differ?

Gastrointestinal endoscopy has grown dramatically over the past century, and with subsequent improvements in technology and anaesthesia, it has become a safe and useful tool for evaluation of GI pathology in children. There are substantial differences between paediatric and adult endoscopy beyond size, including: age-related patho-physiology and the different spectrum of diseases in children. Literature on endoscopic procedures in children is sparse but significant. The present review aims at describing the current knowledges on paediatric endoscopy practice and highlights the main areas of differences between paediatric and adult practice.

Intranasal drugs for analgesia and sedation in children admitted to pediatric emergency department: a narrative review

Acute pain is one of the most common symptoms in children admitted to the Pediatric Emergency Department (PED) and its management represents a real clinical challenge for pediatricians. Different painful procedures can be very stressful for young children and their perception of pain can be enhanced by emotional factors, such as anxiety, distress, or anger. Adequate procedural sedation reduces anxiety and emotional trauma for the patient, but it reduces also stress for operators and the time for procedures. We have reviewed the literature on this topic and the drugs covered in these papers were: midazolam, fentanyl, ketamine, and dexmedetomidine. There are several routes of administering for these drugs to provide analgesia and anxiolysis to children: oral, parenteral, or intranasal (IN). Intravenous (IV) sedation, since it involves the use of needles, can be stressful; instead, IN route is a non-invasive procedure and generally well tolerated by children and it has become increasingly widespread. Some medications can be administered by a mucosal atomizer device (MAD) or by drops. The benefits of the atomized release include less drug loss in the oropharynx, higher cerebrospinal fluid levels, better patient acceptability, and better sedative effects. IN midazolam has a sedative, anxiolytic and amnesic effect, but without analgesic properties. Fentanyl and ketamine are mainly used for pain control. Dexmedetomidine has anxiolytic and analgesic properties. In conclusion, IN analgo-sedation is a simple, rapid and painless option to treat pain and anxiety in the PED requiring brief training on the administration process and experience in sedation.

Effect of dexmedetomidine on pulmonary artery pressure in children with congenital heart disease and pulmonary hypertension

Background:

This study was undertaken to determine the effects of dexmedetomidine on pulmonary artery pressure (PAP) in children with congenital heart disease (CHD) and pulmonary hypertension (PH) undergoing cardiac catheterization with and without a planned intervention during monitored anesthetic care using midazolam and ketamine.

Materials and Methods:

Children (<18 years) with known CHD and PH who were scheduled for cardiac catheterization and interventional procedures were included in the study. The procedures were performed under monitored anesthesia. After obtaining baseline PAPs, an intravenous (IV) infusion of dexmedetomidine (1 μg/kg) was given for over 10 min. During infusion, heart rate (HR), blood pressure (BP), respiratory rate (RR), and peripheral arterial oxygen saturation (SPO₂) were recorded every 2 min until completion of dexmedetomidine infusion, 15 min later, and when the procedure was completed. In addition, pulmonary artery systolic and diastolic pressures, and mean pulmonary artery pressure (MPAP) were recorded and the pulmonary artery systolic pressure (PASP)/systolic blood pressure (BP) ratio was calculated.

Results:

All children tolerated the procedure without adverse events. The HR decreased significantly over time during dexmedetomidine infusion. The changes in systemic systolic BP and PAPs were not significantly different from the baseline value at all points of measurement as was the ratio between the systolic pulmonary artery and systolic systemic BPs.

Conclusions:

Administration of dexmedetomidine in a dose of 1 μg/kg over 10 min did not significantly alter the PAP in children with CHD and PH. There was a decrease in the HR that was not clinically significant. The children tolerated dexmedetomidine without adverse events.

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.

Analysis of 17 948 pediatric patients undergoing procedural sedation with a combination of intranasal dexmedetomidine and ketamine

BACKGROUND

Intranasal procedural sedation using dexmedetomidine is well described in the literature. The combination of intranasal dexmedetomidine and ketamine is a novel approach for which there are little data on the rate of successful sedation or adverse events.

OBJECTIVES

The aim of this study is to evaluate the rate of successful sedation and adverse events of intranasal procedural sedation using a combination of dexmedetomidine and ketamine for diagnostic examination in children.

METHODS

This was a retrospective study and data were collected after ethics approval. A total of 17 948 pediatric patients (7718 females, 10 230 males) in a tertiary hospital in China were evaluated. Patients received a combination of 2 μg kg^-1 of dexmedetomidine and 1 mg kg^-1 of ketamine intranasally for procedural sedation. The level of sedation and recovery was assessed by the Modified Observer Assessment of Alertness/Sedation scale and the Modified Aldrete Score.

RESULTS

The rate of intranasal sedation success was 93% (16691/17948), intranasal sedation rescue was 1.8% (322/17948), and intranasal sedation failure was 5.2% (935/17948). Sedation success was defined as successful completed the diagnostic examination and obtained adequate diagnostic-quality images and reports. Intranasal sedation success, rescue and failure were respectively defined as sedation success with intranasal a single dose, additional bolus dose and the need for intravenous (IV) medications/inhalation agents. Median sedation time was 62 min (interquartile range: 55-70 min), median time for onset of sedation was 15 min (interquartile range: 15-20 min), and median sedation recovery time was 45 min (interquartile range: 38-53 min). Incidence of adverse events was low (0.58%; 105/17948), with major and minor adverse event being reported in 0.02% (4/17948) and 0.56% (101/17948) patients, respectively. Postoperative nausea and vomiting was the most common (0.3%; 53/17948) minor adverse event.

CONCLUSION

Procedural sedation using a combination of intranasal dexmedetomidine and ketamine is associated with acceptable effectiveness and low rates of adverse events.

Pediatric premedication: a double-blind randomized trial of dexmedetomidine or ketamine alone versus a combination of dexmedetomidine and ketamine

Background

Preoperative anxiety is common in pediatric patients. When dexmedetomidine is used alone for sedation as premedication, children tend to awaken when separated from their parents, and body movements occur during invasive procedures. We tested the hypothesis that the combination of dexmedetomidine and ketamine may be a useful premedication to alleviate preoperative anxiety and improve cooperation during intravenous cannulation in pediatric patients, while producing minimal adverse events.

Methods

A total of 135 children, aged 2–5 years and American Society of Anesthesiologists status I–II, scheduled for eye surgery were randomly allocated to receive intranasal dexmedetomidine 2.5 μg/kg (group D), oral ketamine 3 mg/kg and intranasal dexmedetomidine 2 μg/kg (group DK), or oral ketamine 6 mg/kg (group K) 30 min before surgery. Sedation state was evaluated every 10 min after premedication and emotional state was assessed during separation from their parents and peripheral intravenous cannulation. Adverse events were recorded for 24 h postoperatively. The primary endpoint was the rate of successful intravenous cannulation.

Results

The rate of successful venous cannulation was 47% with dexmedetomidine alone, 68% with ketamine alone, and 80% with combined premedication (P = 0.006). The rate of satisfactory separation from parents was not different among groups. The incidence of adverse events was higher in group K compared with the other two groups (postoperative vomiting, P = 0.0041; respiratory-related complications during the perioperative period, P = 0.0032; and postoperative psychological/psychiatric adverse events, P = 0.0152).

Conclusion

The combination of intranasal dexmedetomidine 2 μg/kg and oral ketamine 3 mg/kg produces satisfactory separation from parents and more successful venous cannulation, allowing children to smoothly accept induction of general anesthesia.

Trial registration

Chinese Clinical Trial Register (Unique identifier: ChiCTR-TRC-14004475, Date of registration: 2 April 2014).

Safety and efficacy of ketamine-dexmedetomidine versus ketamine-propofol combinations for sedation in patients after coronary artery bypass graft surgery

Background and Aims:

Prolonged mechanical ventilation after cardiac surgery is associated with serious complications that increase morbidity and mortality. The present study was designed to compare ketamine-propofol (KP) and ketamine-dexmedetomidine (KD) combinations for sedation and analgesia in patients after coronary artery bypass graft (CABG) surgery as regards hemodynamics, total fentanyl dose, time of weaning from mechanical ventilation, time of extubation, and any adverse outcome.

Materials and Methods:

Seventy post-CABG patients were sedated using ketamine 1 mg/kg IV then 0.25 mg/kg/h infusion combined with either dexmedetomidine or propofol to maintain Ramsay sedation score ≥4 during assisted ventilation. Group KP received ketamine + propofol 1 mg/kg bolus followed by 25–50 μg/kg/min. Group KD received ketamine + dexmedetomidine 1.0 μg/kg over 20 min and then 0.2–0.7 μg/kg/h. Total dose of fentanyl in the first 24 h, time of weaning, time of extubation, mean arterial blood pressure, heart rate, and Intensive Care Unit (ICU) stay time were recorded.

Statistics:

Sample size of 35 patients was calculated for 90% power, α = 0.05, β = 0.1, and anticipated effect size = 0.40 using sample size software (G*Power version 3.00.10, Germany). Analytic statistics was performed on IBM compatible computer using SPSS version 11.5 (IBM, New York, United States) software package under Windows XP operating system. All results presented in the form of mean ± standard deviation. Data compared using unpaired Student's t-test, P < 0.05 was considered as statistically significant.

Results:

Group KD showed a significant decrease in mean time of weaning and extubation in group KD in comparison with group KP (374.05 ± 20.25 min vs. 445.23 ± 21.7 min, respectively, P < 0.001) (432.4 ± 19.4 min and 504 ± 28.7 min, respectively, P < 0.0001). Fentanyl consumption showed a significant decrease in group KD in comparison with group KP (41.94 ± 20.43 μg and 152.8 ± 51.2 μg, respectively, with P < 0.0001). There were insignificant difference between both groups as regards hemodynamic stability and length of ICU stay.

Conclusion:

Using KD combination for sedation, post-CABG surgery provided short duration of mechanical ventilation with less fentanyl dose requirement in comparison with KP with insignificant difference in both groups as regards hemodynamic stability and length of the ICU stay.

Utility and Clinical Profile of Dexmedetomidine in Pediatric Cardiac Catheterization Procedures: A Matched Controlled Analysis

Background. Dexmedetomidine is increasingly used in children undergoing cardiac catheterization procedures. We compared the percentage of surgical time with hemodynamic instability and the incidence of postoperative agitation between pediatric cardiac catheterization patients who received dexmedetomidine infusion and those who did not and the incidence of postoperative agitation. Materials and methods. We matched 653 pediatric patients scheduled for cardiac catheterization. Two separate multivariable linear mixed models were used to assess the association between dexmedetomidine use and intraoperative blood pressure and heart rate instability. A multivariate logistic regression was used for relationship between dexmedetomidine and postoperative agitation. Results. No difference between the study groups was found in the duration of MAP ( P = .867) or heart rate (HR) instabilities ( P = .224). The relationship between dexmedetomidine use and the duration of negative hemodynamic effects does not depend on any of the considered CHD types (all P > .001) or intervention ( P = .453 for MAP and P = .023 for HR). No difference in postoperative agitation was found between the study groups ( P = .590). Conclusion. Our study demonstrated no benefit in using dexmedetomidine infusion compared with other general anesthesia techniques to maintain hemodynamic stability or decrease agitation in pediatric patients undergoing cardiac catheterization procedures.

Diagnostic Cardiac Catheterization in the Pediatric Population

Although the utility of diagnostic cardiac catheterization in the clinical setting has diminished over the last years, due to the emergence of noninvasive imaging modalities, such as echocardiography, magnetic resonance imaging and computed tomography, catheterization for diagnostic reasons still constitutes a valuable tool in certain parts in the workup of pediatric heart disease. As a result, awareness of the main aspects of diagnostic catheterization is of great importance for the clinical cardiologist. In this article, the main variables measured and the main actions performed during diagnostic cardiac catheterization in children are discussed.

Comparison of an Intraoperative Infusion of Dexmedetomidine, Fentanyl, and Remifentanil on Perioperative Hemodynamics, Sedation Quality, and Postoperative Pain Control

We aimed to compare fentanyl, remifentanil and dexmedetomidine with respect to hemodynamic stability, postoperative pain control and achievement of sedation at the postanesthetic care unit (PACU). In this randomized double-blind study, 90 consecutive total laparoscopic hysterectomy patients scheduled for elective surgery were randomly assigned to receive fentanyl (1.0 μg/kg) over 1 minute followed by a 0.4 μg/kg/hr infusion (FK group, n = 30), or remifentanil (1.0 μg/kg) over 1 minute followed by a 0.08 μg/kg/min infusion (RK group, n = 30), or dexmedetomidine (1 μg/kg) over 10 minutes followed by a 0.5 μg/kg/hr infusion (DK group, n = 30) initiating at the end of main procedures of the operation to the time in the PACU. A single dose of intravenous ketorolac (30 mg) was given to all patients at the end of surgery. We respectively evaluated the pain VAS scores, the modified OAA/S scores, the BIS, the vital signs and the perioperative side effects to compare the efficacy of fentanyl, remifentanil and dexmedetomidine. Compared with other groups, the modified OAA/S scores were significantly lower in DK group at 0, 5 and 10 minutes after arrival at the PACU (P < 0.05), whereas the pain VAS and BIS were not significantly different from other groups. The blood pressure and heart rate in the DK group were significantly lower than those of other groups at the PACU (P < 0.05). DK group, at sedative doses, had the better postoperative hemodynamic stability than RK group or FK group and demonstrated a similar effect of pain control as RK group and FK group with patient awareness during sedation in the PACU. (World Health Organization registry, KCT0001524).

Cardiac Arrest in a Heart Transplant Patient Receiving Dexmedetomidine During Cardiac Catheterization

Dexmedetomidine is an α-2 agonist with a sedative and cardiopulmonary profile that makes it an attractive anesthetic in pediatric cardiac patients. Cardiac transplant patients may suffer from acute cellular rejection of the cardiac conduction system and, therefore, are at an increased risk of the electrophysiological effect of dexmedetomidine. We present such a patient who had a cardiac arrest while receiving dexmedetomidine during cardiac catheterization. Because acute cellular rejection of the cardiac conduction system is difficult to diagnose, dexmedetomidine should be used with caution in pediatric heart transplant patients.

Options and Considerations for Procedural Sedation in Pediatric Imaging

As pediatric imaging capabilities have increased in scope, so have the complexities of providing procedural sedation in this environment. While efforts by many organizations have dramatically increased the safety of pediatric procedural sedation in general, radiology sedation creates several special challenges for the sedation provider. These challenges require implementation of additional safeguards to promote safety during sedation while maintaining effective and efficient care. Multiple agent options are available, and decisions regarding which agent(s) to use should be determined by both patient needs (i.e., developmental capacities, underlying health status, and previous experiences) and procedural needs (i.e., duration, need for immobility, and invasiveness). Increasingly, combinations of agents to either achieve the conditions required or mitigate/counterbalance adverse effects of single agents are being utilized with success. To continue to provide effective imaging sedation, it is incumbent on sedation providers to maintain familiarity with continuing evolutions within radiology environments, as well as comfort and competence with multiple sedation agents/regimens. This review discusses the challenges associated with radiology sedation and outlines various available agent options and combinations, with the intent of facilitating appropriate matching of agent(s) with patient and procedural needs.

Dexmedetomidine-ketamine combination and caudal block for superficial lower abdominal and genital surgery in children

BACKGROUND

The use of dexmedetomidine-ketamine combination to perform different diagnostic and surgical pediatric procedures has increased. The optimal ketamine dose to combine with dexmedetomidine has not been determined. The goal of this study was to determine the ED50 and ED95 of ketamine, which in combination with, dexmedetomidine (1 μg · kg(-1)) provides an adequate anesthetic effect to perform a caudal block and then the ensuing superficial lower abdominal or genital surgery.

MATERIAL AND METHODS

Twenty-five patients, aged 1-8 years, scheduled for superficial lower abdominal or genital surgery, were studied. All patients received an intravenous dose of dexmedetomidine 1 μg · kg(-1) and a random dose of ketamine from 1 mg · kg(-1) to 2 mg · kg(-1). After ketamine administration, a caudal block was performed and then surgery was initiated. Hemodynamics, respiratory variables, sedation level, and postoperative complications were recorded. The ED50 and ED95 of ketamine were calculated using logistic regression analysis.

RESULTS

The ED50 and ED95 of ketamine to perform a caudal block were 1.53 (1.29-1.76) mg · kg(-1) and 2.25 (1.63-2.88) mg · kg(-1), respectively. The ED50 and ED95 of ketamine to perform a caudal block and to complete the entire procedure were 1.76 (1.57-1.95) mg · kg(-1), and 2.21 (1.77-2.64) mg · kg(-1), respectively. Three patients presented mild, self-limited, intraoperative bradycardia.

CONCLUSIONS

These results suggest that adding ketamine 2 mg · kg(-1) to dexmedetomidine 1 μg · kg(-1) should produce an effective anesthetic level to perform a caudal block and the ensuing superficial lower abdominal or genital surgery in children.

A comparative study on monitored anesthesia care

Aim:

The aim of this study is to compare the effectiveness, hemodynamic changes and duration of sedation and analgesia between combinations of fortwin-phenergan-midazolam (FPM) and ketamine - midazolam (KM) along with local anesthesia for the surgeries done under the umbrella of monitored anesthesia care.

Materials and Methods:

A total of 50 patients undergoing surgeries as tympanoplasty, septoplasty, lip repair, dacrocystectomy and cataract under local anesthesia, randomly received either intravenous (IV) fortwin 0.3 mg/kg over 1 min followed by IV midazolam 0.04 mg/kg plus IV phenergan 12.5 mg (Group FPM) or IV ketamine 0.3 mg/kg over 1 min plus IV midazolam 0.04 mg/kg (Group KM). Sedation was titrated to Ramsay sedation score (RSS) of 3. Patients’ mean arterial pressure (MAP), heart rate (HR), saturation peripheral pulse, duration of sedation and need for intraoperative rescue sedation/analgesic were recorded and compared. Satisfaction of patients (using a 1-7 point Likert verbal rating scale) and readiness for discharge towards (time to Aldrete score of 10) were also determined.

Result:

Group KM had significant rise in HR (20-25%) and MAP (25-30%) from 30 min after the bolus dose given until the end of the surgery in contrast to Group FPM. The target sedation level (RSS ≥ 3) was higher in Group FPM (n = 23 [92%]) as compared with Group KM (n = 12 [48%]). Time until need for rescue sedation was 66.96 ± 17.19 min in FPM and 32.80 ± 8.90 min in KM group. The patient satisfaction (Likert scale) is more with the FPM group (6.12 ± 0.83 vs. 4.40 ± 1.20).

Conclusion:

We found that the combination of FPM is superior to the KM combination as per the hemodynamic changes, duration of analgesia, patients’ satisfaction and efficacy of the drugs are concerned.

Dexmedetomidine premedication in relevance to ketamine anesthesia: A prospective study

Background:

Ketamine-induced hemodynamic pressor response and psychomimetic effects should be attenuated by appropriate premedication. The present study was designed to evaluate the clinical efficacy and safety of dexmedetomidine premedication for balancing the ketamine-induced hemodynamic pressor response and psychomimetic effects.

Materials and Methods:

A total of 80 normotensive adult consented patients of ASA grade I and II of both genders, aged 21 to 55 years, who met the inclusion criteria for elective surgery under ketamine anesthesia were randomized for this prospective blind study and divided into two treatment groups of 40 patients each. Group I patients received premedication of midazolam and Group II patients received premedication of dexmedetomidine. Anesthetic and surgical techniques were standardized. Both groups were assessed for changes in heart rate and systolic blood pressure intraoperatively and psychomimetic effects with behavioral changes postoperatively.

Results:

Preoperatively, all patients were awake. Intraoperatively, the heart rate was 116.6±4.2 in group I versus 76.8±5.8 in group II (P value 0.0004) and systolic blood pressure was 153.07±16.05 in group I versus 139.17±19.9 in group II (P value 0.001). Post-anesthetic psychomimetic responses were not statistically significant between groups.

Conclusion:

The dexmedetomidine premedication effectively attenuated the ketamine induced hemodynamic pressor response and post-anesthetic delirium effects.

Dexmedetomidine, ketamine, and midazolam for oral rehabilitation: a case report

Intravenous sedation is frequently provided by anesthesiologists for phobic patients undergoing elective dental treatment in outpatient settings. Propofol is one of the most commonly used anesthetic agents that can result in apnea and respiratory depression, thereby posing potential difficulties with perioperative airway management. Dexmedetomidine has been utilized successfully in intravenous sedation for a wide variety of procedures and holds potential as an alternative to propofol in outpatient dental settings. However, as a single agent, it may not provide adequate depth of sedation and analgesia for oral rehabilitation. In this case report we demonstrate an effective alternative intravenous deep-sedation technique for an adult phobic patient undergoing oral rehabilitation utilizing 3 agents in combination: dexmedetomidine, ketamine, and midazolam. This combination of agents may be especially useful for those patients with a history of substance abuse, where administration of opioids may be undesirable or contraindicated.

Sedation for paediatric transcatheter atrial septal defect closure: comparison of two sedation protocols

AIM

This study aimed to compare the effects of dexmedetomidine-propofol and ketamine-propofol sedation on haemodynamic stability, immobility, and recovery time in children who underwent transcatheter closure of atrial septal defects.

METHODS

In all, 46 children scheduled for transcatheter closure of atrial septal defects (n = 46) were included. The dexmedetomidine-propofol group (n = 23) received dexmedetomidine (1 μg/kg) and propofol (1 mg/kg) for induction, followed by dexmedetomidine (0.5 μg/kg/hour) and propofol (100 μg/kg/minute) for maintenance. The ketamine-propofol group (n = 23) received ketamine (1 mg/kg) and propofol (1 mg/kg) for induction, followed by ketamine (1 mg/kg) and propofol (100 μg/kg/minute) for maintenance.

RESULTS

In all, 11 patients in the dexmedetomidine group (47.8%) and one patient (4.3%) in the ketamine group demonstrated a decrease ≥20% from the baseline in mean arterial pressure (p = 0.01). Heart rates decreased ≥20% from the baseline value in 10 patients (43.4%) in the dexmedetomidine group and three patients (13%) in the ketamine group (p = 0.047). Heart rate values were observed to be lower in the dexmedetomidine group throughout the procedure after the first 10 minutes. The number of patients requiring additional propofol was higher in the dexmedetomidine group (p = 0.01). The recovery times were similar in the two groups--15.86 ± 6.50 minutes in the dexmedetomidine group and 19.65 ± 8.19 minutes in the ketamine group; p = 0.09.

CONCLUSION

The ketamine-propofol combination was less likely to induce haemodynamic instability, with no significant change in recovery times, compared with the dexmedetomidine-propofol combination. The ketamine-propofol combination provided good conditions for the intervention.

Dexmedetomidine and ketamine sedation for muscle biopsies in patients with Duchenne muscular dystrophy

BACKGROUND

Duchenne muscular dystrophy (DMD) possesses many potential challenges for anesthetic care. Invasive and noninvasive procedures with corresponding sedation or general anesthesia are frequent and necessary for affected patients. There remains a need for a better agent or agents for procedural sedation in patients with comorbid diseases. This study prospectively evaluated a combination of ketamine with two different doses of dexmedetomidine for sedation during muscle biopsy in patients with DMD.

METHODS

Dexmedetomidine 1.0 or 0.5 μg·kg(-1) was administered as a loading dose over 3 min followed by a continuous infusion of 1.0 or 0.5 μg·kg·h(-1). Ketamine (1 mg·kg(-1)) was administered along with the dexmedetomidine loading dose. As the procedure commenced, additional doses of ketamine (0.5 mg·kg(-1)) were administered as needed. Sedation scores, hemodynamic data, operative times, and recovery times were recorded.

RESULTS

The study cohort included a total of 53 bicep, deltoid, or anterior tibialis muscle biopsies in 19 boys including 24 in the dexmedetomidine 1.0 μg·kg(-1) group and 29 in the dexmedetomidine 0.5 μg·kg(-1) group. Mean age and weight were 9.7 ± 1.4 years and 33.3 ± 7.7 kg in the dexmedetomidine 1.0 μg·kg(-1) group and 8.8 ± 1.8 years and 30.2 ± 10.8 kg in the dexmedetomidine 0.5 μg·kg(-1) group. No significant changes in blood pressure were noted. A decrease in heart rate (HR) occurred after the loading dose of dexmedetomidine in both groups. The HR was significantly lower in the dexmedetomidine 1.0 μg·kg(-1) group compared with the dexmedetomidine 0.5 μg·kg(-1) group. Total recovery time to discharge was significantly shorter in the dexmedetomidine 0.5 μg·kg(-1) group than the dexmedetomidine 1.0 μg·kg(-1) group (146 ± 65 vs 174 ± 58 min; P = 0.03), although the total ketamine dose was significantly greater in the dexmedetomidine 0.5 μg·kg(-1) group (3.7 ± 1.0 vs 2.0 ± 0.5 mg·kg(-1); P < 0.01). There were no episodes of apnea or hypoventilation; however, a jaw thrust was needed in one patient in the dexmedetomidine 1.0 μg·kg(-1) group.

CONCLUSION

The combination of dexmedetomidine and ketamine is safe and effective for moderately painful procedures with limited respiratory and cardiovascular effects in a high-risk patient population. Dexmedetomidine 0.5 μg·kg(-1) as a loading dose with ketamine followed by a continuous infusion of dexmedetomidine at 0.5 μg·kg(-1) ·h(-1) achieved an adequate sedation level with shorter total recovery times in the perioperative unit compared with a higher dose regimen of dexmedetomidine (1.0 μg·kg(-1) loading dose followed by an infusion at 1.0 μg·kg(-1) ·h(-1)).

Dexmedetomidine: a review of applications for cardiac surgery during perioperative period

Cardiac surgery is associated with a high incidence of cardiovascular and other complications during the perioperative period that translate into increased mortality and prolonged hospital stays. Safe comprehensive perioperative management is required to eliminate these adverse events. Dexmedetomidine is a selective α2-adrenoreceptor agonist that has been described as an ideal medication in the perioperative period of cardiac surgery. The major clinical effects of dexmedetomidine in this perioperative period can be summarized as attenuating the hemodynamic response, cardioprotective effects, antiarrhythmic effects, sedation in the ICU setting, treatment of delirium, and procedural sedation. Although there are some side effects of dexmedetomidine, it is emerging as an effective therapeutic agent in the management of a wide range of clinical conditions with an efficacious, safe profile. The present review serves as an overview update in the diverse applications of dexmedetomidine for cardiac surgery during the perioperative period.

Dexmedetomidine: a review of applications for cardiac surgery during perioperative period

Cardiac surgery is associated with a high incidence of cardiovascular and other complications during the perioperative period that translate into increased mortality and prolonged hospital stays. Safe comprehensive perioperative management is required to eliminate these adverse events. Dexmedetomidine is a selective α2-adrenoreceptor agonist that has been described as an ideal medication in the perioperative period of cardiac surgery. The major clinical effects of dexmedetomidine in this perioperative period can be summarized as attenuating the hemodynamic response, cardioprotective effects, antiarrhythmic effects, sedation in the ICU setting, treatment of delirium, and procedural sedation. Although there are some side effects of dexmedetomidine, it is emerging as an effective therapeutic agent in the management of a wide range of clinical conditions with an efficacious, safe profile. The present review serves as an overview update in the diverse applications of dexmedetomidine for cardiac surgery during the perioperative period.

Case series: Dexmedetomidine and ketamine for anesthesia in patients with uncorrected congenital cyanotic heart disease presenting for non-cardiac surgery

The number of patients with uncorrected congenital cyanotic heart disease is less but at times some may present for non-cardiac surgery with a high anesthetic risk. Some of these may even be adults with compromised cardiopulmonary physiology posing greater challenges to the anesthesiologist. The authors have used a combination of dexmedetomidine and ketamine for anesthesia for non cardiac surgery in five patients with cyanotic heart disease and right to left shunt (3-Eisenmenger's syndrome, 2-Tetralogy of Fallot). The sympathoinhibitory effects of dexmedetomidine were balanced with the cardiostimulatory effects of ketamine, thereby maintaining good cardiovascular stability. The analgesia was good and there was no postoperative agitation. This drug combination was effective and safe for patients with cyanotic heart disease for non cardiac surgeries.

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.

Dexmedetomidine for patients undergoing diagnostic cardiac procedures: a noninferiority study

When anesthetizing children with congenital heart disease for diagnostic cardiac catheterization, anesthesiologists and cardiologists seek to use anesthetic regimens that yield minimal hemodynamic changes and allow for spontaneous ventilations. Recently, dexmedetomidine has been used as an anesthesia adjunct because of its sedative and analgesic properties and minimal ventilatory depressive effects. We tested the hypothesis that the combination of sevoflurane and dexmedetomidine is non-inferior to sevoflurane alone as it refers to hemodynamic measurements during diagnostic cardiac catheterization in children with a transplanted heart, one ventricle (Fontan procedure), or normal cardiac physiology. Patients were anesthetized with inhalation of sevoflurane in nitrous oxide/oxygen and, after baseline hemodynamic measurements, successive boluses of dexmedetomidine followed by continuous infusion were administered. In this study, non-inferiority was shown when differences at steady-state (dexmedetomidine + sevoflurane) compared to baseline (sevoflurane alone) and its associated 95% confidence interval fell completely within the range of plus or minus 20%. Forty-one (26 normal physiology, 9 cardiac transplantation, and 6 Fontan) patients were enrolled. Non-inferiority of sevoflurane + dexmedetomidine compared with sevoflurane alone was shown for heart rate, but not for arterial blood pressure in patients with normal and cardiac transplant physiology. In patients with normal cardiac physiology, non-inferiority was demonstrated for bispectral index. Therefore, while the lack of depressive respiratory effects and non-inferiority for heart rate are desirable, the lack of non-inferiority of dexmedetomidine + sevoflurane combination for arterial blood pressure do not justify the routine use of this combination compared with sevoflurane alone for children with congenital heart disease undergoing cardiac catheterization.

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.

Preliminary experience with a combination of dexmedetomidine and propofol infusions for diagnostic cardiac catheterization in children

No specific regimen has been universally accepted as ideal for procedural sedation during cardiac catheterization in infants and children. In this paper, we retrospectively describe our preliminary experience with a continuous infusion of dexmedetomidine and propofol for sedation during cardiac catheterization in children with congenital heart disease. The short-half life of these two drugs creates a potential for easier titration, quicker recovery and less prolonged sedation-related adverse effects. This combination was not only able to limit the dose of either drugs, but was also very stable from cardio-respiratory standpoint. There were no adverse effects noted in our two patients. This initial experience showed that the combination of propofol and dexmedetomidine as a continuous infusion may be a suitable alternative for sedation in spontaneously breathing children undergoing cardiac catheterization.

Dexmedetomidine-ketamine sedation during upper gastrointestinal endoscopy and biopsy in a patient with Duchenne muscular dystrophy and egg allergy

Sedation during invasive procedures provides appropriate humanitarian care as well as facilitating the completion of procedure. Although generally safe and effective, adverse effects may occur especially in patients with co-morbid diseases. In many cases, given its rapid onset and offset, propofol is chosen to provide sedation during various invasive procedures. We present a nine-year-old, 45 kg child with Duchenne muscular dystrophy (DMD) who presented for esophagogastroduodenoscopy (EGD). Given the egg allergy, which was a relative contraindication to the use of propofol, and the potential risk of malignant hyperthermia due to DMD, a combination of dexmedetomidine and ketamine was used for procedural sedation. Dexmedetomidine was administered as a loading dose of 1 μg/kg along with a single bolus dose of ketamine (1 mg/kg). This was followed by a dexmedetomidine infusion at 0.5 μg/kg/hour. The patient tolerated the procedure well and was discharged to home. Previous reports regarding the use of dexmedetomidine and ketamine for procedural sedation are reviewed and the potential efficacy of this combination is discussed.

Dexmedetomidine and ketamine: an effective alternative for procedural sedation?

OBJECTIVES

Although generally effective for sedation during noninvasive procedures, dexmedetomidine as the sole agent has not been uniformly successful for invasive procedures. To overcome some of the pitfalls with dexmedetomidine as the sole agent, there are an increasing number of reports regarding its combination with ketamine. This article provides a descriptive account of the reports from the literature regarding the use of a combination of dexmedetomidine and ketamine for procedural sedation.

DATA SOURCE

A computerized bibliographic search of the literature regarding dexmedetomidine and ketamine for procedural sedation.

MEASUREMENTS AND MAIN RESULTS

The literature contains four reports with cohorts of more than ten patients with a total of 122 patients. Two of these studies were prospective randomized trials. Additionally, there are eight single case reports or small case series (six patients or less) with an additional 21 pediatric patients. When used together, dexmedetomidine may prevent the tachycardia, hypertension, salivation, and emergence phenomena from ketamine, whereas ketamine may prevent the bradycardia and hypotension, which has been reported with dexmedetomidine. An additional benefit is that the addition of ketamine to initiate the sedation process speeds the onset of sedation, thereby eliminating the slow onset time when dexmedetomidine is the sole agent. Although various regimens have been reported in the literature, the most effective regimen appears to be the use of a bolus dose of both agents, dexmedetomidine (1 µg/kg) and ketamine (1-2 mg/kg), to initiate sedation. This can then be followed by a dexmedetomidine infusion (1-2 µg/kg/hr) with supplemental bolus doses of ketamine (0.5-1 mg/kg) as needed.

CONCLUSIONS

The available literature except for one trial is favorable regarding the utility of a combination of ketamine and dexmedetomidine for procedural sedation. Future studies with direct comparisons to other regimens appear warranted for both invasive and noninvasive procedures.

Is the addition of dexmedetomidine to a ketamine-propofol combination in pediatric cardiac catheterization sedation useful?

Pediatric patients undergoing cardiac catheterization usually need deep sedation. In this study, 60 children were randomly allocated to receive sedation with either a ketamine-propofol combination (KP group, n = 30) or a ketamine-propofol-dexmedetomidine combination (KPD group, n = 30). Both groups received 1 mg/kg of ketamine and 1 mg/kg of propofol for induction of sedation, and the KPD group received an additional 1 μg/kg of dexmedetomidine infusion during 5 min for induction of sedation and a maintenance infusion of 0.5 μg/kg/h. In both groups, 0.2 mg/kg of propofol was administered as a bolus to maintain a Ramsey sedation score (RSS) greater than 4 throughout the procedure. None of the patients in either group required intubation. In the KP group, one patient required mask ventilation. The chin-lift maneuver needed to be performed for eight patients in the KP group and one patient in the KPD group (p < 0.05). Adding dexmedetomidine to the ketamine-propofol combination decreased movement during the procedures. The heart rate in the KPD group was significantly lower after induction of sedation and throughout the procedure (p < 0.05). No significant differences in systolic blood pressure, diastolic blood pressure, or respiration rates were found between the two groups (p > 0.05). The mean recovery time was longer in the KP group (5.86 vs 3.13 min; p < 0.05). Adding dexmedetomidine to a ketamine-propofol combination led to a reduced need for airway intervention and to decreased movement during local anesthetic infiltration and throughout the procedure. The recovery time was shorter and hemodynamic stability good in the KPD group.

Perioperative care for the older outpatient undergoing ambulatory surgery

As the number of ambulatory surgery procedures continues to grow in an aging global society, the implementation of evidence-based perioperative care programs for the elderly will assume increased importance. Given the recent advances in anesthesia, surgery, and monitoring technology, the ambulatory setting offers potential advantages for elderly patients undergoing elective surgery. In this review article we summarize the physiologic and pharmacologic effects of aging and their influence on anesthetic drugs, the important considerations in the preoperative evaluation of elderly outpatients with coexisting diseases, the advantages and disadvantages of different anesthetic techniques on a procedural-specific basis, and offer recommendations regarding the management of common postoperative side effects (including delirium and cognitive dysfunction, fatigue, dizziness, pain, and gastrointestinal dysfunction) after ambulatory surgery. We conclude with a discussion of future challenges related to the growth of ambulatory surgery practice in this segment of our surgical population. When information specifically for the elderly population was not available in the peer-reviewed literature, we drew from relevant information in other ambulatory surgery populations.

Dexmedetomidine-Ketamine Sedation in a Child With a Mediastinal Mass

Sedation during invasive procedures provides appropriate humanitarian care as well as facilitates the completion of procedures. Although generally safe and effective, adverse effects may occur especially in patients with comorbid diseases. One particularly challenging situation is the child with an anterior mediastinal mass who requires sedation during performance of a biopsy to obtain a tissue diagnosis. When there is evidence of airway compromise, it is generally accepted that the maintenance of spontaneous ventilation is necessary as complete airway obstruction may occur, if positive pressure ventilation is chosen. We present the use of a dexmedetomidine–ketamine combination for procedural sedation in a three-year-old child who presented with a large mediastinal mass and respiratory compromise. Previous reports regarding the use of dexmedetomidine and ketamine for procedural sedation are reviewed and the potential efficacy of this combination is discussed.

A high dose of dexmedetomidine using the BIS monitor™ for diagnostic and interventional cardiac catheterization in a toddler with congenital heart disease

Dexmedetomidine (DEX) for sedation in diagnostic and interventional cardiac catheterization (DICC) has been reported to require other drugs or rescue drugs because of its insufficient sedative effect when used alone. We administered DEX and adjusted its dose according to the bispectral index (BIS) monitor™ for DICC in a toddler; consequently, a high dose of DEX had to be administered. The patient was a 1-year and 4-month-old boy who was scheduled to undergo DICC after intracardiac repair. We used DEX alone as the sedative because this was expected to avoid oxygen supply and mechanical ventilation and to produce a safe situation for procedures around the neck. DEX was administered at the dose of 1-15 μg/kg/h according to BIS monitor™; administration of cardiovascular drugs or oxygen supply or assist ventilation, except chin lift, were not needed. The maximum predicted plasma concentration (pCp) of DEX and mean pCp were calculated as 6.1 and 4.1 ng/mL, respectively. A high dose of DEX may be required for DICC sedation, as for MRI sedation, in many cases. Although further studies should be conducted to reveal the merits and demerits of DEX in cardiac catheterization, a high dose of DEX may be useful in some cases.

Dexmedetomidine: applications for the pediatric patient with congenital heart disease

This study aimed to provide a general description of the cardiovascular and hemodynamic effects of dexmedetomidine and an evidence-based review of the literature regarding its use in infants and children with congenital heart disease (CHD). A computerized bibliographic search of the literature on dexmedetomidine use in infants and children with CHD was performed. The cardiovascular effects of dexmedetomidine have been well studied in animal and adult human models. Adverse cardiovascular effects include occasional episodes of bradycardia, with rare reports of sinus pause or cardiac arrest. Both hypotension and hypertension also have been reported. The latter is related to peripheral α(2B) agonism leading to vasoconstriction. No adverse effects on the pulmonary vasculature have been noted even in patients with preexisting pulmonary hypertension. Although there are no direct effects on myocardial function, decreased cardiac output may result from changes in heart rate or increases in afterload. Although not currently Food and Drug Administration (FDA)-approved for the pediatric population, findings have shown dexmedetomidine to be effective in various clinical scenarios of patients with CHD including sedation during mechanical ventilation, prevention of procedure-related anxiety, prevention of emergence delirium and shivering after anesthesia, and treatment of withdrawal. Although dexmedetomidine may have limited utility for painful or invasive procedures, preliminary data suggest that the addition of ketamine to the regimen may offer benefits. When used during the perioperative period, additional benefits include blunting of the sympathetic stress response with a reduction of endogenous catecholamine release, a decrease in intraoperative anesthetic requirements, and a limitation of postoperative opioid requirements.

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.

Comparison of an Intraoperative Infusion of Dexmedetomidine or Remifentanil on Perioperative Haemodynamics, Hypnosis and Sedation, and Postoperative Pain Control

This prospective, randomized, double-blind study compared the effects of dexmedetomidine and remifentanil on haemodynamic stability, sedation and postoperative pain control in the postanaesthetic care unit (PACU). Fifty consecutive patients scheduled for total laparoscopic hysterectomy were randomly assigned to receive infusions of either dexmedetomidine (1 μg/kg) i.v. over 10 min followed by 0.2-0.7 μg/kg per h continuous i.v. infusion or remifentanil (0.8-1.2 μg/kg) i.v. over 1 min followed by 0.05-0.1 μg/kg i.v. per min, starting at the end of surgery to the time in the PACU. Modified observer's assessment of alertness scores were significantly lower in the dexmedetomidine group than in the remifentanil group at 0, 5 and 10 min after arrival in the PACU. Blood pressure and heart rate in the dexmedetomidine group were significantly lower than that recorded in the remifentanil group in the PACU. Dexmedetomidine, at the doses used in this study, had a significant advantage over remifentanil in terms of postoperative haemodynamic stability.