Controlled hypotension in children: a critical review of available agents

Evaluation for Blood Concentration and Efficacy/Safety of Continuous Administration of Thiamylal in Children

BACKGROUND

Thiamylal exerts excellent sedative effects. However, it is not routinely used because of its serious adverse effects. This study aimed to clarify the target blood concentration range and infusion rate of thiamylal in children by measuring its blood concentration and evaluating its relationship with efficacy and adverse effects.

METHODS

This study was approved by the Ethics Committee of Japanese Red Cross Kumamoto Hospital. The authors included 10 children aged between 1 and 7 years who had received continuous intravenous (IV) infusion of thiamylal for the management of refractory status epilepticus, excluding those who met the exclusion criteria. After a 2 mg/kg bolus injection of thiamylal, continuous IV infusion was initiated at a rate of 2-3 mg/kg/h. Thiamylal concentration in the blood was measured using high-performance liquid chromatography. The State Behavioral Scale and the frequency of bolus injections were used to evaluate efficacy. Blood pressure and heart rate were measured to evaluate adverse effects. Statistical analyses of the time to awakening and the factors affecting it were also conducted.

RESULTS

The State Behavioral Scale score during thiamylal administration was -2 or lower in all cases, suggesting that the depth of sedation was sufficient. The frequency of bolus injections decreased in a blood concentration-dependent manner, suggesting that the frequency tended to decrease, especially at thiamylal blood concentrations of 20 mcg/mL or higher. An increase of the infusion rate to 3 mg/kg/h was recommended, because the blood concentration may not reach 20 mcg/mL at an infusion rate of 2 mg/kg/h. There was also a case in which a rapid increase in blood concentration accompanied by a decrease in blood pressure and heart rate was observed when the infusion rate was increased to 4 mg/kg/h. Furthermore, the time to awakening after the end of administration correlated with the highest blood concentration during administration; therefore, delayed awakening was noted when using a high dose of thiamylal.

CONCLUSIONS

The target blood concentration of thiamylal in children should be 20-30 mcg/mL, and the infusion rate should be based on 3 mg/kg/h.

Anesthesia and Perioperative Management for Surgical Correction of Neuromuscular Scoliosis in Children: A Narrative Review

Scoliosis is the most frequent spinal deformity in children. It is defined as a spine deviation of more than 10° in the frontal plane. Neuromuscular scoliosis is associated with a heterogeneous spectrum of muscular or neurological symptoms. Anesthesia and surgery for neuromuscular scoliosis have a higher risk of perioperative complications than for idiopathic scoliosis. However, patients and their relatives report improved quality of life after the surgery. The challenges for the anesthetic team result from the specifics of the anesthesia, the scoliosis surgery itself, or factors associated with neuromuscular disorders. This article includes details of preanesthetic evaluation, intraoperative management, and postoperative care in the intensive care unit from an anesthetic view. In summary, adequate care for patients who have neuromuscular scoliosis requires interdisciplinary cooperation. This comprehensive review covers information about the perioperative management of neuromuscular scoliosis for all healthcare providers who take care of these patients during the perioperative period, with an emphasis on anesthesia management.

Use of dexmedetomidine for controlled hypotension in middle ear surgery: A systematic review and meta-analysis

BACKGROUND

Microsurgical operations such as middle ear surgery rely heavily on visibility of the surgical field. Anesthetic techniques such as controlled hypotension have been developed to improve surgical field visibility by attempting to decrease bleeding. Many agents have been utilized to achieve controlled hypotension intraoperatively. Dexmedetomidine is a relatively newer agent which works on alpha-2 receptors to decrease sympathetic tone. This paper sought to determine the efficacy of dexmedetomidine for optimizing surgical field visibility in MES.

METHODS

A comprehensive search strategy was used in PubMed, SCOPUS, CINAHL, and CENTRAL through August 9, 2022 for this systematic review and meta-analysis.

INCLUSION CRITERIA

adult patients undergoing middle ear surgery with dexmedetomidine used for controlled hypotension to improve surgical field visibility. Risk of bias was assessed via Cochrane RoB 2. Meta-analysis of mean difference for surgical field scores and risk ratios for positive surgical field scores were used to compare dexmedetomidine with placebo or other agents.

RESULTS

Fourteen studies were included in this review. Statistically significant mean difference was found to favor dexmedetomidine over placebo for Fromme-Boezaart surgical field scores. Statistically significant results were also demonstrated favoring dexmedetomidine over other agents in risk ratio for receiving positive surgical field scores, as well as surgeon and patient satisfaction scores.

CONCLUSIONS

Controlled hypotension is an invaluable tool for surgical field visibility. Improved surgical field visibility was observed with dexmedetomidine compared with placebo and various other agents. Risk of sub-optimal bleeding scores was significantly lower with dexmedetomidine. Dexmedetomidine is effective at improving surgical field visibility in middle ear surgery.

Intranasal dexmedetomidine sedation for paediatric MRI by radiology personnel: A retrospective observational study

BACKGROUND

MRI often requires sedation or anaesthesia to ensure good image quality in paediatric patients. Access to paediatric anaesthesia services is, however, a limiting factor for effective paediatric MRI service, and alternative sedation methods are, therefore, warranted.

OBJECTIVE

To investigate the efficacy and safety of an intranasal dexmedetomidine sedation program for paediatric MRI, without immediate presence of anaesthesia personnel.

DESIGN

Single institution retrospective observational study.

SETTING

Tertiary care paediatric hospital.

PATIENTS

Children 0 to 12 years, ASA risk class 1 or 2 with heart rate within age-appropriate limit.

INTERVENTION

Radiology personnel administered an initial dose of intranasal dexmedetomidine of 4 μg kg -1 followed by a second dose of 2 μg kg -1 to the patients if needed. Recordings of image quality, critical events, heart rate, pulse oximetry saturation and noninvasive blood pressure before and after dexmedetomidine administration were made.

MAIN OUTCOME MEASURES

Changes in haemodynamic and respiratory data before vs. after intranasal dexmedetomidine were analysed for changes, and the incidence of critical events was evaluated as well as rate of successful MRI scans.

RESULTS

One thousand and ninety-one MRIs under intranasal dexmedetomidine sedation were included (mean age 34 months, 95% confidence interval (CI), 33 to 36, 599 male individuals). A success rate of 93% (95% CI, 91 to 94%) was found. No major critical events were recorded, total incidence of minor issues was 0.2% (95% CI, 0 to 0.7%). Five children had a heart rate under a preset minimal limit after dexmedetomidine (0.4%; 95% CI, 0.1 to 0.9%). Significant decreases in heart rate and mean arterial pressure, within acceptable limits not requiring intervention, was seen after dexmedetomidine administration.

CONCLUSION

Intranasal dexmedetomidine sedation without immediate presence of anaesthesia personnel appears to be well tolerated and associated with minimal interference on MRI image quality.

TRIAL REGISTRATION

clinicaltrials.org NCT05163704, retrospectively registered.

Value in Scoliosis Surgery: Coordinated Surgical and Anesthetic Techniques Avoid Blood Transfusion without Fibrinolytic Medications or Red Blood Cell Salvage

STUDY DESIGN

Retrospective chart review.

OBJECTIVE

The aim of this study was to document the impact of coordinated surgical and anesthetic techniques on estimated blood loss (EBL) and subsequent need for transfusion.

SUMMARY OF BACKGROUND DATA

Scoliosis surgery is typically associated with large quantities of blood loss, and consequently blood transfusion may be necessary. Many strategies have been employed to minimize blood loss, including blood collection with reinfusion ("cell-saver") and the use of antifibrinolytic drugs. We reviewed our experience with methods to minimize blood loss to show that transfusion should be a rare event.

METHODS

One hundred and thirty consecutive cases of spine fusion for adolescent idiopathic scoliosis utilizing pedicle screw fixation were reviewed from March 2013 to October 2019. The senior author was the primary surgeon for all cases. Data were collected from the electronic medical record, including age, sex, weight, number of instrumented levels, EBL, total fluids administered during surgery, pre- and postoperative hemoglobin, and procedure duration.

RESULTS

The average EBL was 232 ± 152 mL (range 37-740 mL). The average preoperative hemoglobin was 13.4 ± 1.2 g/dL and the average postoperative hemoglobin (last measured before discharge) was 9.0 ± 1.2 g/dL. One patient received a transfusion of 270 mL homologous blood. Blood salvage and reinfusion ("cell-saver") was not used. No patient was managed with antifibrinolytic drugs.

CONCLUSION

Minimizing blood loss using a combination of surgical and anesthesia techniques can effectively eliminate the need for blood transfusion. The elimination of costly adjuncts increases the value of a complex orthopedic procedure.Level of Evidence: 5.

Evaluation of cerebral oxygen saturation during hypotensive anesthesia in functional endoscopic sinus surgery

Background and Aims

Controlled hypotensive anesthesia in endoscopic sinus surgery would provide a clean surgical field. Cerebral oxygen saturation (ScO₂) is important in endoscopic sinus surgery patients and it may be low during controlled hypotension. The aim of the present study was to assess ScO₂ in these patients.

Material and Methods

In this observational study, 41 patients who underwent endoscopic sinus surgery with hypotensive anesthesia were enrolled for the study and all of the patients received the same anesthetic medication, nitroglycerin for controlled hypotension. Variables were measured prior to surgery, after induction of anesthesia, 5 min, and every 30 min after controlled hypotension. Near-infrared spectroscopy was used for ScO₂ evaluation. Mean arterial blood pressure (MAP) was maintained at 55-60 mmHg in the surgical duration. We used t-test, Wilcoxon, and repeated measures analysis of variance (ANOVA). We examined the cross-correlation functions of the time series data between end-tidal carbon dioxide (ETCO₂)/MAP and ScO₂.

Results

The mean of intraoperative ScO₂ was not significantly different from the baseline evaluation (P > 0.05). ETCO₂ was cross correlated with current ScO₂ [r: 0.618, confidence interval (CI) 95%: 0.46-0.78]. We found moderate cross correlation between the MAP and current ScO₂ (r: 0.728, CI 95%: 0.56-0.88). About 92% of the patients recovered within 30 min. Recovery time was associated with intraoperative MAP (P: 0.004, r: 0.438), intraoperative ETCO₂ (P: 0.003, r: 0.450), and ScO₂ (P: 0.026, r: 0.348).

Conclusions

Based on our findings, the assessment of ScO₂ and maintained MAP >55 mmHg may provide safe conditions for endoscopic sinus surgery.

Pediatric endonasal dacryocystorhinostomy: A multicenter series of 116 cases

We report our experience with pediatric endonasal dacryocystorhinostomy (DCR). Multicenter, retrospective, noncomparative study. Cases of pediatric endonasal DCR during 2006-2011 were included from six oculoplastic units. Patients over the age of 16 years were excluded. The outcomes of pediatric endonasal DCR are presented. Indication for surgery, demographics, previous interventions, intraoperative or postoperative complications, follow-up duration, and success rate (defined as significant improvement of epiphora) were evaluated. In total, 116 endonasal DCRs were performed for 103 patients. The mean follow-up period was 8 months (range 3 months to 4 years), with 1 patient lost to follow-up. There were 48 males (mean age 5 years and 9 months) and 50 females (range of 4 months to 16 years), with a total of 98 cases of congenital nasolacrimal duct obstruction (CNLDO) (84.5%) and 18 cases of acquired nasolacrimal duct obstruction (ANLDO) (15.5%). Previous interventions included probing 75.9% (88/116), massaging 43.1% (50/116), and intubation 39.7% (46/116). There were no intraoperative complications. There was one case of postoperative pyogenic granuloma. There were no cases of postoperative infection and postoperative hemorrhage. Ninety percent of procedures were considered successful. Complete symptom resolution was observed in 78% (90/116), significant improvement in 12% (14/116), partial improvement in 2% (2/116), and no improvement in 8% (9/116). In our series, we demonstrated that endonasal DCR is a safe operation and has an overall success rate of 90% for pediatric NLDO.

The efficacy of Labetalol versus Nitroglycerin for induction of controlled hypotension during sinus endoscopic surgery. A prospective, double-blind and randomized study

OBJECTIVE

To assess the efficacy of labetalol versus nitroglycerin for induction of controlled hypotension during sinus endoscopic surgery.

DESIGN

A prospective, double-blind and randomized study.

SETTING

Carried out in operating room in university hospital.

PATIENTS

60 patients of both sexes, American Society of Anesthesiologists (ASA) physical status I and II, age range from 20 to 60years; scheduled for elective sinus endoscopic surgery under general anesthesia (GA).

INTERVENTIONS

Patients were divided into two groups (30 each). NTG group received nitroglycerin infusion at a dose of 2-5μg/kg/min, LAB group received labetalol infusion at a dose of 0.5-2mg/min.

MEASUREMENTS

Surgical condition was assessed by surgeon using average category scale (ACS) of 0-5, a value of 2-3 being ideal. In both groups mean arterial blood pressure (MAP) was gradually reduced till the ideal ACS for assessment of surgical condition, the target of ACS was 2-3 or lower.

RESULTS

Both studied drugs achieved desired hypotension and improved visualization of surgical field by decreasing bleeding in the surgical site, but ideal surgical conditions were created at mild hypotension (MAP 70-75) in LAB group while same conditions were created at MAP of 65-69mmHg in NTG group. Mean heart rate (HR) was significantly higher in NTG group as compared to LAB group. Blood loss decreased significantly in LAB group.

CONCLUSION

Both labetalol and NTG are effective and safe drugs for induction of controlled hypotension during sinus endoscopic surgery. While, labetalol was better as it offered optimum operative condition with mild decrease in blood pressure, decreased surgical bleeding and less tachycardia during the surgery.

Deliberate hypotension with propofol under anaesthesia for functional endoscopic sinus surgery (FESS)

BACKGROUND

Functional endoscopic sinus surgery (FESS) is a minimally invasive technique that is used to treat chronic sinusitis. Small bleeding areas can reduce operative visibility and result in destruction of surrounding structures. Deliberate hypotension (lowering the mean arterial blood pressure to between 50 and 65 mm Hg in normotensive patients) using a range of pharmacological agents during general anaesthesia reduces blood loss in many operations. This review was originally published in 2013 and updated in February 2016.

OBJECTIVES

We aimed to compare the use of propofol versus other techniques for achieving deliberate intraoperative hypotension during FESS procedures with regard to blood loss and operative conditions.

SEARCH METHODS

We searched the following databases in the updated review: the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 2), MEDLINE (1950 to February 2016), Embase (1980 to February 2016), LILACS (1982 to February 2016), and ISI Web of Science (1946 to February 2016). We also searched the reference lists of relevant articles and conference proceedings and contacted the authors of included trials.

SELECTION CRITERIA

We sought all randomized controlled trials comparing propofol with other techniques for deliberate hypotension during FESS with regard to blood loss and operative conditions in both adults and children. Our primary outcome was total blood loss (TBL). Other outcomes included surgical field quality, operation time, mortality within 24 hours, complications, and failure to reach target blood pressure.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Two review authors independently extracted details of trial methodology and outcome data from the reports of all trials considered eligible for inclusion. We made all analyses on an intention-to-treat basis where possible. When I2 was less than 40% and the P value from the Chi2 test was higher than 0.10, we pooled data using the fixed-effect model. Otherwise, we pooled data using the random-effects model.

MAIN RESULTS

We found no new studies. This updated review therefore includes four studies with 278 participants. Most analyses were based on data from few participants and low-quality evidence, so our results should be interpreted with caution. Deliberate hypotension with propofol did not decrease TBL (millilitres) when compared with inhalation anaesthetics in either children (1 study; 70 participants; very low-quality evidence), or adults (1 study; 88 participants; moderate-quality evidence). Propofol improved the quality of the surgical field by less than one category on a scale from 0 (no bleeding) to 5 (severe bleeding) (mean difference -0.64, 95% CI -0.91 to -0.37; 4 studies; 277 participants; low-quality evidence), but no difference in operation time was reported (3 studies; 214 participants; low-quality evidence). Failure to lower blood pressure to target was less common in the propofol group (risk ratio of failure with propofol 0.24, 95% CI 0.09 to 0.66; 1 study; 88 participants; moderate-quality evidence).

AUTHORS' CONCLUSIONS

Using propofol to achieve deliberate hypotension probably improves the surgical field, but the effect is small. Deliberate hypotension with propofol did not decrease TBL and the operation time. However, due to the very low quality of the evidence, this conclusion is not definitive. Randomized controlled trials with good-quality methodology and large sample size are required to investigate the effectiveness of deliberate hypotension with propofol for FESS.

Nitroglycerine, esmolol and dexmedetomidine for induced hypotension during functional endoscopic sinus surgery: A comparative evaluation

Background and Aim:

Induced hypotension limits intra-operative blood loss to provide better visibility of the surgical field and diminishes the incidence of major complications during functional endoscopic sinus surgery (FESS). We aimed at comparing nitroglycerine, esmolol and dexmedetomidine for inducing controlled hypotension in patients undergoing FESS.

Material and Methods:

One hundred and fifty American Society of Anesthesiologists physical status I or II adult patients undergoing FESS under general anesthesia were randomly allocated to three groups of 50 patients each. Group E received esmolol in a loading and maintenance dose of 1 mg/kg over 1 min and 0.5-1.0 mg/kg/h, respectively. Group D received a loading dose of dexmedetomidine 1 μg/kg over 10 min followed by an infusion 0.5-1.0 μg/kg/h, and group N received nitroglycerine infusion at a dose of 0.5-2 μg/kg/min so as to maintain mean arterial pressure (MAP) between 60 and 70 mmHg in all the groups. The visibility of the surgical field was assessed by surgeon using Fromme and Boezaart scoring system. Hemodynamic variables, total intra-operative fentanyl consumption, emergence time and time to first analgesic request were recorded. Any side-effects were noted. The postoperative sedation was assessed using Ramsay Sedation Score.

Result:

The desired MAP (60-70 mmHg) could be achieved in all the three study groups albeit with titration of study drugs during intra-operative period. No significant intergroup difference was observed in Fromme's score during the intra-operative period. The mean total dose of fentanyl (μg/kg) used was found to be significantly lower in group D compared to groups E and N (1.2 ± 0.75 vs. 3.6 ± 1.3 and 2.9 ± 1.1 respectively). The mean heart rate was significantly lower in group D compared to groups E and N at all times of measurement (P < 0.05). The MAP was found to be significantly lower in group D compared to groups E and N after infusion of study drugs, after induction, just after intubation and 5 min after intubation (P < 0.05). The Ramsay Sedation Scores were significantly higher in group D (score 3 in 46%) when compared to group E (score 2 in 50%) and group N (score 2 in 54%) (P < 0.001). The emergence time was significantly lower in group E and group N compared to group D. Time to first analgesic request was significantly longer in group D.

Conclusion:

Dexmedetomidine and esmolol provided better hemodynamic stability and operative field visibility compared to nitroglycerin during FESS. Dexmedetomidine provides an additional benefit of reducing the analgesic requirements and providing postoperative sedation.

A hemodynamic model to guide blood pressure control during deliberate hypotension with sodium nitroprusside in children

Sodium nitroprusside (SNP) has been widely used to control blood pressure in infants and children. The goals of this analysis were to develop models that describe the hemodynamic response to SNP dosing in pediatric patients; examine sources of variation in dose-response, defining age, and size dependencies; and determine vulnerable populations or patient subtypes that may elicit dosing modifications. A multi-center, randomized, double-blinded, parallel-group, dose-ranging, effect-controlled study, followed by an open-label dose titration of an intravenous infusion of SNP was undertaken in 203 pediatric subjects, who required deliberate hypotension or controlled normotension during anesthesia. A total of 3464 MAP measurements collected from 202 patients during the study's blinded phase, including baseline measurements up to 6 min prior to the blinded were available for analysis. A population K-PD model was developed with a one-compartment model assumed for SNP. Size differences in CL and V of the effect compartment were described using theory-based allometry. An inhibitory sigmoidal E_max model was used to describe the effect of SNP. A power function of age was used to describe age-related differences in baseline MAP. A mixture model of two groups with low and high EC50 was used to explain variability in MAP response. Change in MAP was characterized by a linear disease progression slope during the blinded phase. In the final population model, CL and V increased with weight, and baseline MAP increased with age. The effect compartment half-life of SNP was 13.4 min. The infusion rate producing 50% of E_max (ER50) at steady state for high EC50, was 0.34 μg/kg/min and for low EC50 0.103 μg/kg/min. The K-PD model well-describes initial dosing of SNP under controlled circumstances; model-based dosing guidance agrees with current practice. An initial titration strategy supported via algorithm-based feedback should improve maintenance of target MAP.

A prospective, open-label trial of clevidipine for controlled hypotension during posterior spinal fusion

OBJECTIVES

Controlled hypotension is one means to limit or avoid the need for allogeneic blood products. Clevidipine is a short-acting, intravenous calcium channel antagonist with a half-life of 1 to 3 minutes due to rapid metabolism by non-specific blood and tissue esterases. To date, there are no prospective evaluations with clevidipine in the pediatric population. We prospectively evaluated the dosing requirements, efficacy, and safety of clevidipine for ontrolled hypotension during spinal surgery for neuromuscular scoliosis in the pediatric population.

METHODS

Patients undergoing posterior spinal fusion for neuromuscular scoliosis were eligible for inclusion. The study was an open label, observational study. Maintenance anesthesia included desflurane titrated to maintain a bispectral index at 40 to 60 and a remifentanil infusion. Motor and somatosensory evoked potentials were monitored intraoperatively. When the mean arterial pressure (MAP) was ≥ 65 mmHg despite remifentanil at 0.3 mcg/kg/min, clevidipine was added to maintain the MAP at 55 to 65 mmHg. Clevidipine was initiated at 0.25 to 1 mcg/kg/min and titrated up in increments of 0.25 to 1 mcg/kg/min every 3 to 5 minutes to achieve the desired MAP.

RESULTS

The study cohort included 45 patients. Fifteen patients (33.3%) did not require a clevidipine infusion to maintain the desired MAP range, leaving 30 patients including 13 males and 17 females for analysis. These patients ranged in age from 7.9 to 17.4 years (mean ± SD: 13.7 ± 2.2 years) and in weight from 18.9 to 78.1 kg (mean ± SD: 43.4 ± 14.2 kg). Intraoperatively, the clevidipine infusion was stopped in 6 patients as the surgeon expressed concerns regarding spinal cord perfusion and requested a higher MAP than the study protocol allowed. The data until that point were included for analysis. The target MAP was initially achieved at a mean time of 8.9 minutes. Sixteen of the 30 patients (53.3%) achieved the target MAP within 5 minutes. Heart rate (HR) increased from a baseline of 83 ± 16 to 86 ± 15 beats per minute (mean ± SD) (p=0.04) with the administration of clevidipine. No patient had a HR increase ≥ 20 beats per minute or required the administration of a β-adrenergic antagonist. The duration of the clevidipine administration varied from 8 to 527 minutes (mean ± SD: 160 ± 123 minutes). The maintenance infusion rate of clevidipine varied from 0.25 to 5.0 mcg/kg/min (mean ± SD: 1.4 ± 1.1 mcg/kg/min). Clevidipine was paused a total of 43 times in the 30 cases. In 18 of the 30 patients (60%), the clevidipine infusion was temporarily paused more than once due to a MAP < 55 mmHg. A fluid bolus was administered to only 1 patient to treat the low MAP. No patient required the administration of a vasoactive agent for hypotension. When the clevidipine infusion was discontinued as controlled hypotension was no longer required, the MAP returned to baseline or ≥ 65 mmHg within 10 minutes in 12 of the 30 patients (40%).

CONCLUSIONS

Clevidipine can be used to provide controlled hypotension during posterior spinal fusion. The response of the MAP, both the onset and duration of action, were rapid. Although titration of the infusion with occasional pauses of administration may be needed, excessive hypotension was not noted.

Predictors of arterial blood pressure control during deliberate hypotension with sodium nitroprusside in children

BACKGROUND

Sodium nitroprusside (SNP) is used to decrease arterial blood pressure (BP) during certain surgical procedures. There are limited data regarding efficacy of BP control with SNP. There are no data on patient and clinician factors that affect BP control. We evaluated the dose-response relationship of SNP in infants and children undergoing major surgery and performed a quantitative assessment of BP control.

METHODS

One hundred fifty-three subjects at 7 sites received a blinded infusion followed by open-label SNP during operative procedures requiring controlled hypotension. SNP was administered by continuous infusion and titrated to maintain BP control (mean arterial BP [MAP] within ±10% of clinician-defined target). BP was recorded using an arterial catheter. Statistical process control methodology was used to quantify BP control. A multivariable model assessed the effects of patient and procedural factors.

RESULTS

BP was controlled an average 45.4% (SD 23.9%; 95% CI, 41.5%-49.18%) of the time. Larger changes in infusion rate were associated with worse BP control (7.99% less control for 1 μg·kg·min increase in average titration size, P = 0.0009). A larger difference between a patient's baseline and target MAP predicted worse BP control (0.93% worse control per 1-mm Hg increase in MAP difference, P = 0.0013). Both effects persisted in multivariable models.

CONCLUSIONS

SNP was effective in reducing BP. However, BP was within the target range less than half of the time. No clinician or patient factors were predictive of BP control, although 2 inverse relationships were identified. These relationships require additional study and may be best coupled with exposure-response modeling to propose improved dosing strategies when using SNP for controlled hypotension in the pediatric population.

Clevidipine resistance in a patient taking aripiprazole and methylphenidate

Various factors may be responsible for blood pressure alterations during perioperative care. When these physiologic alterations require treatment, several therapeutic options are available. Clevidipine is an ultrashort-acting, intravenous L-type calcium channel antagonist of the dihydropyridine class. Anecdotal experience has demonstrated its efficacy in various clinical scenarios in the pediatric population. We report apparent resistance to the vasodilatory effects of clevidipine in a 13-year-old girl who presented for anesthetic care during posterior spinal fusion for neuromuscular scoliosis whose chronic medication regimen included aripiprazole and methylphenidate for the treatment of depression and attention-deficit/hyperactivity disorder. We discuss the potential interaction of aripiprazole and methylphenidate with the calcium channel antagonists and cellular mechanisms responsible for the resistance to the vasodilatory effects of clevidipine.

Ventricular pacing for induced hypotension in a toddler

Cerebral aneurysm clipping may require periods of hypotension to facilitate dissection and clip application. We describe the use of rapid ventricular pacing to facilitate establishment of controlled hypotension for an 18-month-old child during clipping for giant basilar artery aneurysm. This technique is an alternative to pharmacologic means of inducing hypotension for neurosurgical procedures and has not been previously described in children.

Deliberate hypotensive anesthesia with the rapidly acting, vascular-selective, L-type calcium channel antagonist-clevidipine: a case report

Deliberate hypotension is an important technique for use in select anesthetics for procedures such as orthognathic surgery, specifically LeFort I maxillary osteotomy. We present a case report of an anesthetic involving deliberate hypotension for a 17-year-old female patient who presented for a LeFort I osteotomy, bilateral sagittal split of the mandible, and a genioplasty in order to correct a skeletal class III malocclusion. After reaching a steady-state general anesthetic, deliberate hypotension was induced solely with a bolus and subsequent continuous infusion of the ultrashort acting calcium channel blocker, clevidipine. The preoperative, intraoperative, and postoperative course and anesthetic management are discussed.

Controlled hypotension with desflurane combined with esmolol or dexmedetomidine during tympanoplasty in adults: A double-blind, randomized, controlled trial

BACKGROUND

Controlled hypotension is a technique that is used to limit intraoperative blood loss to provide the best possible surgical field during surgery.

OBJECTIVE

The aim of this double-blind, randomized, controlled study was to compare the effects of desflurane combined with esmolol or dexmedetomidine on the amount of blood in the surgical field, recovery time, and tolerability in adult patients undergoing tympanoplasty.

METHODS

Turkish patients aged 18 to 60 years, classified as American Society of Anesthesiologists physical status I or II, who were scheduled for tympanoplasty were randomly divided into 2 groups: the esmolol group or the dexmedetomidine group. After the anesthesia induction in the esmolol group, a loading dose of esmolol was infused intravenously over 1 minute at 1 mg/kg, followed by a maintenance rate of 0.4 to 0.8 mg/ kg/h. In the dexmedetomidine group, a loading dose of dexmedetomidine was infused intravenously over 10 minutes at a rate of 1 μg/kg, followed by a maintenance rate of 0.4 to 0.8 μg/kg/h. The infusion rates were then titrated to maintain mean arterial pressure (MAP) of 65 to 75 mm Hg. General anesthesia was maintained with desflurane 4% to 6%. Heart rate (HR) and MAP were recorded during anesthesia. The following 6-point scale was used to assess the amount of bleeding in the operative field: 0 = no bleeding, a virtually bloodless field; 1 = bleeding that was so mild that it was not a surgical nuisance; 2 = moderate bleeding that was a nuisance but did not interfere with accurate dissection; 3 = moderate bleeding that moderately compromised surgical dissection; 4 = bleeding that was heavy but controllable and that significantly interfered with surgical dissection; and 5 = massive bleeding that was uncontrollable and made dissection impossible. Scores ≤2 were considered to be optimal surgical conditions. The sedation score was determined at 15, 30, and 60 minutes after tracheal extubation using the following scale: 1 = anxious, agitated, or restless; 2 = cooperative, oriented, and tranquil; 3 = responsive to commands; 4 = asleep, but with brisk response to light, glabellar tap, or loud auditory stimulus; 5 = asleep, sluggish response to glabellar tap or auditory stimulus; and 6 = asleep, no response. Time to extubation and to total recovery from anesthesia (Aldrete score ≥9 on a scale of 0-10), adverse effects (eg, intraoperative hypotension [blood pressure <65 mm Hg], bradycardia [HR <50 beats/min]), intraoperative fentanyl consumption, and postoperative nausea and vomiting were recorded. Arterial blood gas analysis and kidney and liver function tests were conducted. All patients were evaluated by the same attending surgeon and anesthesiologist, both of whom were blinded to the administered study drugs.

RESULTS

Fifty-two consecutive white patients undergoing tympanoplasty were identified. Two patients had to be excluded because of hypertension and 2 refused to participate. Forty-eight patients were equally randomized to either the esmolol group (n = 24 [16 women, 8 men]; mean [SD] age, 38.4 [10.5] years) or the dexmedetomi-dine group (n = 24 [17 women, 7 men]; mean age, 35.5 [14.7] years). Sedation scores were not collected for 1 patient in the esmolol group; therefore, analysis was conducted for 23 patients. The median (range) of the scores for the amount of blood in the surgical field in the esmolol and dexmedetomidine groups was 1 (0-3) and 1 (0-2), respectively (P = NS). Mean intraoperative fentanyl consumption in the esmolol group was significantly higher than in the dexmedetomidine group (50.0 [3.0] vs 25.0 [2.5] μg/min; P = 0.002). In the esmolol group, the mean times to extubation and to recovery from anesthesia were significantly shorter than those of the dexmedetomidine group (7.0 [1.4] vs 9.1 [1.9] minutes, respectively; 5.9 [2.1] vs 7.9 [2.3] minutes; both, P = 0.001). The mean sedation scores were significantly lower in the esmolol group (n = 23, because of intent-to-treat analysis) compared with the dexmedetomidine group at 15 minutes (2.5 [0.6] vs 3.6 [0.5]; P = 0.001) and 30 minutes (2.6 [0.6] vs 3.3 [0.6]; P = 0.001) postoperatively. No significant differences were found between the study groups in regard to blood urea nitrogen or creatinine concentration, aspartate aminotransferase or alanine aminotransferase activities, pH, partial pressure of carbon dioxide, or bicarbonate, before or after the operation.

CONCLUSIONS

Both esmolol and dexmedetomidine, combined with desflurane, provided an effective and well-tolerated method of achieving controlled hypotension to limit the amount of blood in the surgical field in these adult patients undergoing tympanoplasty. Esmolol was associated with significantly shorter extubation and recovery times and significantly less postoperative sedation compared with dexmedetomidine.

Heart rate variability dynamics during controlled hypotension with nicardipine, remifentanil and dexmedetomidine

BACKGROUND

This study was done to investigate how nicardipine, remifentanil and dexmedetomidine affect the balance of the autonomic nervous system in patients receiving controlled hypotension under general anaesthesia by evaluating heart rate variability indices.

METHODS

Sixty-two patients were randomly allocated to either the nicardipine-sevoflurane (Group N, n = 21), remifentanil-sevoflurane (Group R, n = 21) or dexmedetomidine-sevoflurane (Group D, n = 20) group for controlled hypotension during orthognathic surgery. Electrocardiogram data acquisition was done after vital sign stabilization following anaesthesia induction (T1) and 30 min after controlled hypotension was induced (T2).

RESULTS

Total power and low frequency (LF) power was significantly decreased at T2 compared with T1 in all groups, while a decrease in high frequency (HF) power was only observed in Group N (P < 0.001). LF/HF ratios of Group R and D were significantly suppressed at T2 compared with T1 (P = 0.001 and P < 0.001, respectively), but was increased Group N (P = 0.009). The LF/HF ratio of Group N was significantly higher than Group R and D at T2 (P < 0.001 in both), with Group D showing a significantly lower LF/HF ratio compared with Group R (P < 0.001).

CONCLUSIONS

Remifentanil and dexmedetomidine did not have sympathetic nervous system-stimulating effects during controlled hypotension, while remifentanil seemed to be superior in preserving the overall balance in autonomic nervous system activity. Nicardipine was found to stimulate the sympathetic nervous system, which may be problematic in patients vulnerable to disturbances in the autonomic nervous system.

A Comparison of the Effects of Esmolol and Dexmedetomidine on the Clinical Course and Cost for Controlled Hypotensive Anaesthesia

OBJECTIVE

To compare the effects of esmolol (β-blocker) and dexmedetomidine (α-2-agonist) on patients' clinical course and cost of application of controlled hypotension during middle-ear surgery.

METHODS

Fifty ASA I-II patients scheduled for tympanomastoidectomy were enrolled in the study and were randomized into two groups. Bispectral Index (BIS) and neuromuscular monitoring (TOF GUARD-SX) were applied to all patients. In group E (n=25), 0.5 mg kg(-1) min(-1) esmolol was infused over 1 min before induction and titrated over a range of 10-200 μg kg(-1) min(-1); in group D (n=25), 0.5 μg kg(-1) dexmedetomidine was infused over 10 minutes before induction, and then titrated over a range of 0.2-0.7 μg kg(-1) hr(-1) to maintain mean arterial pressure (MAP) between 55 and 65 mmHg and BIS 40-50 after induction. In both groups, 0.25 μg kg(-1) min(-1) remifentanil infusion was used for anaesthesia maintenance. Maintaining end-tidal CO2 (EtCO2) at 35-40, using 1 MAC sevoflurane in 50% O2-air mixture, mechanical ventilation was started. The effects of both agents on hemodynamic conditions [(heart rate (HR), mean arterial pressure (MAP)], neuromuscular blockage [onset of action (OA), duration of clinical action (DCA), recovery index (RI)], amount of bleeding, surgeon satisfaction, and total dexmedetomidine and esmolol doses used during the intervention were recorded and costs were compared between the groups.

RESULTS

No significant difference was present in hemodynamic conditions, bleeding scores or surgeon satisfaction between groups. Although OA was similar in both groups, DCA and RI were significantly higher in group D. Cost was significantly higher with esmolol than dexmedetomidine.

CONCLUSION

We conclude that although both agents are feasible in inducing hypotensive anaesthesia, while neuromuscular block time prolonged by using dexmedetomidine, higher costs were observed with esmolol.

Induced hypotension for functional endoscopic sinus surgery: A comparative study of dexmedetomidine versus esmolol

OBJECTIVE

A comparative study to evaluate the efficacy of dexmedetomidine as a hypotensive agent in comparison to esmolol in Functional Endoscopic Sinus Surgery (FESS).

METHODS

Forty patients ASA I or II scheduled for FESS were equally randomly assigned to receive either dexmedetomidine 1 μg/Kg over 10 min before induction of anesthesia followed by 0.4-0.8 μg/Kg/h infusion during maintenance (DEX group), or esmolol, loading dose 1mg/kg was infused over one min followed by 0.4-0.8 mg/kg/h infusion during maintenance (E group) to maintain mean arterial blood pressure (MAP) between (55-65 mmHg). General anesthesia was maintained with sevoflurane 2%-4%. The surgical field was assessed using Average Category Scale and average blood loss was calculated. Hemodynamic variables (MAP and HR); arterial blood gas analysis; plasma cortisol level; intraoperative fentanyl consumption; Emergence time and total recovery from anesthesia (Aldrete score ≥9) were recorded. Sedation score was determined at 15, 30, 60 min after tracheal extubation and time to first analgesic request was recorded.

RESULT

Both DEX group and E group reached the desired MAP (55-65 mmHg) with no intergroup differences in MAP or HR. The for the quality of the surgical filed in the range of MAP (55-65 mmHg) were <=2 with no significant differences between group scores during hypotensive period. Mean intraoperative fentanyl consumption was significantly lower in DEX group than E group. Cortisol level showed no significant changes between or within groups. No significant changes were observed in arterial blood gases. Emergence time and time to achieve Aldrete score ≥9 were significantly lower in E group compared with DEX group. The sedation score were significantly lower in E group compared with DEX group at 15 and 30 minutes postoperatively. Time to first analgesic request was significantly longer in DEX group.

CONCLUSION

Both dexmedetomidine or esmolol with sevoflurane are safe agents for controlled hypotension and are effective in providing ideal surgical field during FESS. Compared with esmolol, dexmedetomidine offers the advantage of inherent analgesic, sedative and anesthetic sparing effect.

Deliberate hypotension with propofol under anaesthesia for functional endoscopic sinus surgery (FESS)

BACKGROUND

Functional endoscopic sinus surgery (FESS) is a minimally invasive technique that is used to treat chronic sinusitis. Small bleeding areas can reduce operative visibility and result in destruction of surrounding structures. Deliberate hypotension (lowering the mean arterial blood pressure to between 50 and 65 mm Hg in normotensive patients) using a range of pharmacological agents during general anaesthesia reduces blood loss in many operations.

OBJECTIVES

We aimed to compare the use of the intravenous anaesthetic agent propofol versus other techniques for deliberate hypotension during FESS with regard to blood loss and operative conditions.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 1), MEDLINE (1950 to April 2012), EMBASE (1980 to April 2012), LILACS (1982 to April 2012) and ISI Web of Science (1946 to April 2012). We also searched the reference lists of relevant articles and conference proceedings and contacted the authors of included trials.

SELECTION CRITERIA

We sought all randomized controlled trials (RCTs) conducted to compare propofol with other techniques. Our primary outcome was total blood loss (TBL). Other outcomes included surgical field quality, operation time, mortality within 24 hour, complications and failure to reach target blood pressure.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted details of trial methodology and outcome data from reports of all trials considered eligible for inclusion. All analyses were made on an intention-to-treat basis where possible. When I(2) was < 40% and the P value from the Chi(2) test was > 0.10, we pooled data by using the fixed-effect model. Otherwise we pooled data by using the random-effects model.

MAIN RESULTS

We included four studies with 278 participants in the review. Deliberate hypotension with propofol did not decrease TBL (millilitres) when compared with inhalation anaesthetics in either children or adults. Propofol improved the quality of the surgical field by less than one category on a scale from 0 (no bleeding) to 5 (severe bleeding) (mean difference (MD) 0.64 better with propofol, 95% confidence interval (CI) 0.37 to 0.91 better), but no difference in operation time was reported. Failure to lower blood pressure to target was less common in the propofol group (relative risk of failure with propofol (RR) 0.24, 95% CI 0.09 to 0.66).

AUTHORS' CONCLUSIONS

Using propofol to achieve deliberate hypotension may improve the surgical field, but the effect is small. Deliberate hypotension with propofol did not decrease TBL and operation time. RCTs with good quality methodology and large sample size are required to investigate the effectiveness of deliberate hypotension with propofol for FESS.

Controlled hypotension and blood loss during frontoorbital advancement

OBJECT

Controlled hypotension is routinely used during open repair of craniosynostosis to decrease blood loss, although this benefit is unproven. In this study the authors analyzed the longitudinal relationships between intraoperative mean arterial pressure (MAP) and calculated blood loss (CBL) during frontoorbital advancement (FOA) for craniosynostosis.

METHODS

The authors reviewed the records of infants with craniosynostosis who had undergone primary FOA between 1997 and 2009. Anesthesia records provided preoperative and serial intraoperative MAP. Interval measures of CBL had been determined during the course of the operation. The longitudinal relationships between MAP(mean), MAP(change), and CBL(change) were assessed over the same time interval and compared between adjacent time intervals to determine the directionality of associations.

RESULTS

Ninety infants (44 males and 46 females) underwent FOA at a mean age and weight of 10.7 ± 12.9 months and 9.0 ± 7.0 kg, respectively. The average intraoperative MAP was 56.1 ± 4.8 mm Hg, 22.6 ± 12.1% lower than preoperative baseline. A negative correlation was found between CBL(change) and MAP(mean) over the same interval (r = -0.31, p < 0.05), and an inverse relationship was noted between CBL(change) of the previous interval and MAP(change) of the next interval (r = -0.07, p < 0.05). Finally, there was no significant association between MAP(change) of the previous interval and CBL(change) of the next interval.

CONCLUSIONS

Calculated blood loss demonstrated a negative correlation with MAP during FOA. Directionality testing indicated that MAP did not affect intraoperative blood loss; instead, blood loss drove changes in MAP. Overall, these findings challenge the benefit of controlled hypotension during open craniofacial repair.

Blood transfusion risks and alternative strategies in pediatric patients

Although the safety of the blood supply has been greatly improved, there still remain both infectious and noninfectious risks to the patient. The incidence of noninfectious transfusion reactions is greater than that of infectious complications. Furthermore, the mortality associated with noninfectious risks is significantly higher. In fact, noninfectious risks account for 87-100% of fatal complications of transfusions. It is concerning to note that the majority of pediatric reports relate to human error such as overtransfusion and lack of knowledge of special requirements in the neonatal age group. The second most frequent category is acute transfusion reactions, majority of which are allergic in nature. It is estimated that the incidence of adverse outcome is 18:100,000 red blood cells issued for children aged less than 18 years and 37:100,000 for infants. The comparable adult incidence is 13:100,000. In order to decrease the risks associated with transfusion of blood products, various blood-conservation strategies can be utilized. Modalities such as acute normovolemic hemodilution, hypervolemic hemodilution, deliberate hypotension, antifibrinolytics, intraoperative blood salvage, and autologous blood donation are discussed and the pediatric literature is reviewed. A discussion of transfusion triggers, and algorithms as well as current research into alternatives to blood transfusions concludes this review.

Pharmacokinetics And Pharmacodynamics Of Fenoldopam Mesylate For Blood Pressure Control In Pediatric Patients

BACKGROUND

Fenoldopam mesylate, a selective dopamine1-receptor agonist, is used by intravenous infusion to treat hypertension in adults. Fenoldopam is not approved by the FDA for use in children; reports describing its use in pediatrics are limited. In a multi-institutional, placebo controlled, double-blind, multi-dose trial we determined the pharmacokinetic (PK) and pharmacodynamic (PD) characteristics and side-effect profile of fenoldopam in children.

METHODS

Seventy seven (77) children from 3 weeks to 12 years of age scheduled for surgery in which deliberate hypotension would be induced were enrolled. Patients were randomly assigned to one of five, blinded treatment groups (placebo or fenoldopam 0.05, 0.2, 0.8, or 3.2 mcg/kg/min iv) for a 30-minute interval after stabilization of anesthesia and placement of vascular catheters. Following the 30-minute blinded interval, investigators adjusted the fenoldopam dose to achieve a target mean arterial pressure in the open-label period until deliberate hypotension was no longer indicated (e.g., muscle-layer closure). Mean arterial pressure and heart rate were continuously monitored and were the primary endpoints.

RESULTS

Seventy-six children completed the trial. Fenoldopam at doses of 0.8 and 3.2 mcg/kg/min significantly reduced blood pressure (p < 0.05) during the blinded interval, and doses of 1.0-1.2 mcg/kg/min resulted in continued control of blood pressure during the open-label interval. Doses greater than 1.2 mcg/kg/min during the open-label period resulted in increasing heart rate without additional reduction in blood pressure. Fenoldopam was well-tolerated; side effects occurred in a minority of patients. The PK/PD relationship of fenoldopam in children was determined.

CONCLUSION

Fenoldopam is a rapid-acting, effective agent for intravenous control of blood pressure in children. The effective dose range is significantly higher in children undergoing anesthesia and surgery (0.8-1.2 mcg/kg/min) than as labeled for adults (0.05-0.3 mcg/kg/min). The PK and side-effect profiles for children and adults are similar.

Renal effects of fenoldopam in critically ill pediatric patients: A retrospective review

OBJECTIVE

Published data describe the use of fenoldopam in adults for treatment of oliguria/anuria and for renal perfusion and protection, but pediatric data are scant. We assessed the effects of fenoldopam on urine output and potential deleterious changes in hemodynamics or serum creatinine in children.

DESIGN

Retrospective analysis.

SETTING

Academic institution.

PATIENTS

: All patients <or=18 yrs old at our institution who received >or=24 hrs of fenoldopam therapy. Exclusion criteria included mechanical circulatory support, initiation of fenoldopam in the operating room, and age >18 yrs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Demographics, renal function, fenoldopam dosing, concomitant inotropes, and inotrope score data were collected and analyzed. Thirteen patients (age 0.3-18.7 yrs, median 5.5 yrs) received a mean infusion dose of 0.07 +/- 0.08 microg/kg/min (range 0.01-0.26 microg/kg/min) over the first 24 hrs of therapy. Eight patients received fenoldopam to augment urine output, and five patients received fenoldopam to increase renal perfusion. Nine (69%) patients received dopamine concurrently. Mean inotrope score at the beginning of therapy was 11.3 +/- 7.6 and did not change during therapy. Mean urine output increased from 1.82 +/- 1.5 mL/kg/hr to 2.74 +/- 1.4 mL/kg/hr (p = .009) in the first 24 hrs of fenoldopam therapy. No change in serum creatinine occurred (p not significant). Blood urea nitrogen was significantly different from baseline (41.7 +/- 18.7 vs. 49.0 +/- 19.8 mg/dL, p = .02). Patients with lower baseline urine output had a greater increase in urine output with fenoldopam. One patient experienced clinically significant hypotension while receiving fenoldopam, which was thought to be due to a concurrent nitroprusside infusion.

CONCLUSIONS

Fenoldopam increases urine output in select critically ill pediatric patients without requiring escalation of inotropic support. There were no adverse hemodynamic effects or alterations in serum creatinine. Further prospective pediatric studies to define the role of fenoldopam in children are warranted.

Controlled hypotension: a guide to drug choice

For half a century, controlled hypotension has been used to reduce bleeding and the need for blood transfusions, and provide a satisfactory bloodless surgical field. It has been indicated in oromaxillofacial surgery (mandibular osteotomy, facial repair), endoscopic sinus or middle ear microsurgery, spinal surgery and other neurosurgery (aneurysm), major orthopaedic surgery (hip or knee replacement, spinal), prostatectomy, cardiovascular surgery and liver transplant surgery. Controlled hypotension is defined as a reduction of the systolic blood pressure to 80-90 mm Hg, a reduction of mean arterial pressure (MAP) to 50-65 mm Hg or a 30% reduction of baseline MAP. Pharmacological agents used for controlled hypotension include those agents that can be used successfully alone and those that are used adjunctively to limit dosage requirements and, therefore, the adverse effects of the other agents. Agents used successfully alone include inhalation anaesthetics, sodium nitroprusside, nitroglycerin, trimethaphan camsilate, alprostadil (prostaglandin E1), adenosine, remifentanil, and agents used in spinal anaesthesia. Agents that can be used alone or in combination include calcium channel antagonists (e.g. nicardipine), beta-adrenoceptor antagonists (beta-blockers) [e.g. propranolol, esmolol] and fenoldopam. Agents that are mainly used adjunctively include ACE inhibitors and clonidine. New agents and techniques have been recently evaluated for their ability to induce effective hypotension without impairing the perfusion of vital organs. This development has been aided by new knowledge on the physiology of peripheral microcirculatory regulation. Apart from the adverse effects of major hypotension on the perfusion of vital organs, potent hypotensive agents have their own adverse effects depending on their concentration, which can be reduced by adjuvant treatment. Care with use limits the major risks of these agents in controlled hypotension; risks that are generally less important than those of transfusion or alternatives to transfusion. New hypotensive drugs, such as fenoldopam, adenosine and alprostadil, are currently being evaluated; however, they have disadvantages and a high treatment cost that limits their development in this indication. New techniques of controlled hypotension subscribe to the use of the natural hypotensive effect of the anaesthetic drug with regard to the definition of the ideal hypotensive agent. It must be easy to administer, have a short onset time, an effect that disappears quickly when administration is discontinued, a rapid elimination without toxic metabolites, negligible effects on vital organs, and a predictable and dose-dependent effect. Inhalation agents (isoflurane, sevoflurane) provide the benefit of being hypnotic and hypotensive agents at clinical concentrations, and are used alone or in combination with adjuvant agents to limit tachycardia and rebound hypertension, for example, inhibitors of the autonomic nervous system (clonidine, beta-blockers) or ACE inhibitors. When they are used alone, inhalation anaesthetics require high concentrations for a significant reduction in bleeding that can lead to hepatic or renal injury. The greatest efficacy and ease-of-use to toxicity ratio is for techniques of anaesthesia that associate analgesia and hypotension at clinical concentrations without the need for potent hypotensive agents. The first and oldest technique is epidural anaesthesia, but depending on the surgery, it is not always appropriate. The most recent satisfactory technique is a combination treatment of remifentanil with either propofol or an inhalation agent (isoflurane, desflurane or sevoflurane) at clinical concentrations. In light of the current literature, and because of their safety and ease of use, these two techniques are preferred.

Use of fenoldopam to increase urine output in a patient with renal insufficiency secondary to septic shock: A case report

OBJECTIVE

We describe the use of fenoldopam to increase urine output in a pediatric patient with sepsis, heart failure, oliguria, and volume overload.

DESIGN

Case report.

SETTING

A tertiary pediatric intensive care unit.

PATIENT

A 17-year-old male who was being treated for acute lymphoblastic leukemia and was admitted from outside the hospital to the pediatric intensive care unit, in septic shock, after a course of chemotherapy.

INTERVENTIONS

A continuous fenoldopam infusion of 0.03 microg/kg/min was added to a regimen of multiple inotropic and vasopressor agents and a furosemide continuous infusion.

MEASUREMENTS AND MAIN RESULTS

Urine output increased 586% 12 hrs after starting the fenoldopam infusion and 775% from baseline 24 hrs after starting the infusion. Diuretics were decreased while maintaining adequate urine output. No hypotension was noted.

CONCLUSIONS

Fenoldopam increased urine output in a pediatric patient who was in septic shock and oliguria. The mechanism for this effect is unclear, and further trials are necessary to determine the role of fenoldopam in this patient population.

Dexmedetomidine-Ketamine and Propofol-Ketamine Combinations for Anesthesia in Spontaneously Breathing Pediatric Patients Undergoing Cardiac Catheterization

OBJECTIVE

The purpose of this study was to compare the effects of dexmedetomidine-ketamine and propofol-ketamine combinations on hemodynamics, sedation level, and the recovery period in pediatric patients undergoing cardiac catheterization.

DESIGN

Prospective, randomized trial.

SETTING

University hospital.

PARTICIPANTS

Children (n = 44) undergoing cardiac catheterization.

INTERVENTIONS

The dexmedetomidine plus ketamine group (group 1, n = 22) received an infusion over 10 minutes of 1 microg/kg of dexmedetomidine and ketamine, 1 mg/kg, as a bolus, for induction. The patients then received an infusion of 0.7 microg/kg/h of dexmedetomidine and 1 mg/kg/h of ketamine for maintenance. The propofol plus ketamine group (group 2, n = 22) received 1 mg/kg of propofol and 1 mg/kg of ketamine for induction. The patients received 100 microg/kg/min of propofol and 1 mg/kg/h of ketamine by infusion for maintenance. Additional doses of ketamine, 1 mg/kg, were administered when a patient showed discomfort in both groups.

MEASUREMENTS AND MAIN RESULTS

Hemodynamic data, respiratory rate, bispectral index, and sedation scores were recorded after induction and every 15 minutes thereafter. The time to reach a Steward recovery score of 6 was recorded. The heart rate in group 1 was significantly lower (average 10-20 beats/min) than group 2 after induction and throughout the procedure. Ketamine consumption in group 1 was significantly more than in group 2 (2.03 mg/kg/h v 1.25 mg/kg/h) for maintenance (p < 0.01). The recovery time was also longer in group 1 than in group 2 (49.54 v 23.16 minutes, respectively; p < 0.01).

CONCLUSIONS

The dexmedetomidine-ketamine combination was not superior to a propofol-ketamine combination because of insufficient sedation and analgesia and a longer recovery time.

Perioperative management of ventricular assist devices in children and adolescents

Ventricular assist devices are an integral part of therapy for patients with end-stage heart failure. Devices can either bridge to recovery or to transplantation. Options for ventricular assist devices include those that are centrifugal, pulsatile, and new rotary/axial devices. Care of the patient on a ventricular assist device is multifaceted, involving pharmacologic or mechanical support of the right ventricle, management of systemic vascular resistance, and manipulation of the hematologic system to avoid bleeding or thrombosis. In addition, care of these patients involves support of all end organs and avoidance of infectious complications. Care of these patients is complex, requiring a highly integrated team for optimal outcome.