Current practice for the chemical immobilisation of non-domestic feline species: An online survey study

BACKGROUND

Safe chemical immobilisation of wild felids is essential for both conservational management and clinical purposes. However, little is known about drug protocols and current practice.

METHODS

This study was designed as an online survey based on a questionnaire. Descriptive/correlation statistics and analysis of proportions were used for data analysis.

RESULTS

The preferred immobilisation technique was the use of darts (37% of the respondents), while the most popular drug combination was a mixture of benzodiazepines, alpha-2 adrenoreceptor agonists and dissociative anaesthetics (27%). The inclusion of ketamine in the drug mixture was associated with a quicker anaesthetic onset, as estimated by the participants (p < 0.001). Common complications were prolonged recovery (46%), bradycardia (35%), hypoventilation (32%), hypothermia (26%) and arousal (26%). Commonly encountered problems were inappropriate equipment (39%), lack of suitable drugs (27%) and inadequate knowledge of species-specific pharmacology (29%) and physiology (24%).

LIMITATIONS

Incomplete adherence to the Checklist for Reporting Results of Internet E-Surveys is acknowledged.

CONCLUSIONS

Drug protocols including both alpha-2 adrenoreceptor agonists and dissociative anaesthetics are preferred in wild felids, and the inclusion of ketamine may be useful to achieve a quick onset. Equipment/drug availability and species-specific knowledge are potential areas of improvement to improve wild felid anaesthesia.

Pharmacokinetics of Ketamine Transfer Into Human Milk

PURPOSE/BACKGROUND

Ketamine is an N -methyl- d -aspartate-antagonistic dissociative anesthetic infused intermittently for off-label management of treatment-resistant depression, acute suicidality, and postpartum depression. Despite the prevalence of postpartum depression nearing upward of 15% of deliveries, almost no research has been done to evaluate its safety during lactation.

METHODS

In this study, human milk samples were released from the InfantRisk Center's Human Milk Biorepository of 4 participants treated with intermittent ketamine infusions (49-378 mg) to determine the levels of the drug and its active norketamine metabolite using liquid chromatography-mass spectrometry.

RESULTS

The absolute infant dose of ketamine from human milk was 0.003 to 0.017 mg/kg per day, and norketamine was 0.005 to 0.018 mg/kg per day. The relative infant dose (RID) for ketamine ranged from 0.34% to 0.57%. The RID for norketamine ranged from 0.29% to 0.95%. There were no reported infant adverse effects.

CONCLUSION

The findings of this study suggest that the transfer of ketamine, as well as its active metabolite, norketamine, into human milk is minimal, as estimated by RIDs less than 1% in all participants. These relative doses are well below standardly accepted safety thresholds.

Ketamine-dexmedetomidine combination for sedation in pediatric major surgery in a low-income country

Anorectal malformations are one of the most frequent congenital malformations treated by pediatric surgeons. In low-income countries, the surgical and anesthetic management of children in need of these procedures can be challenging. Limited oxygen supply, lack of equipment, especially pediatric, and intensive care units make the use of regional anesthesia appealing. We present a series of four cases of anorectal malformations corrections in Guinea Bissau, in children up to 13 months of age, under regional anesthesia and sedation with ketodex, a mixture of ketamine and dexmedetomidine (in a proportion of 1 mg to 1 μg). No child developed respiratory depression requiring airway intervention or supplemental oxygen, or had hemodynamic instability.

A Systematic Review of Recreational Nitrous Oxide Use: Implications for Policy, Service Delivery and Individuals

BACKGROUND

Nitrous oxide (N₂O) is a dissociative anaesthetic that is sometimes used recreationally. The prevalence of N₂O use is difficult to quantify but appears to be increasing. Research on N₂O harms and application of harm reduction strategies are limited. The aim of this mixed method systematic review was to collate and synthesise the disparate body of research on recreational nitrous oxide use to inform harm reduction approaches tailored for young people.

METHODS

To identify publications reporting the recreational use of N₂O, a search of public health, psychology and social science databases was conducted. Databases included PubMed, CIHNAL, PsycINFO, Scopus and Web of Science. Grey literature and Google advanced search were also used. Due to limited published literature on the recreational use of N₂O, no limit was placed on publication date or study type. A thematic synthesis extracted descriptive and analytical themes from the selected studies. Quality appraisal was conducted using the CASP Tool for Qualitative studies and the Joanna Briggs Institute case report assessment tool.

RESULTS

The search retrieved 407 reports. Thirty-four were included in the final analysis, including sixteen case reports. The included studies were primarily concerned with raising awareness of the apparently increasing use and subsequently increasing harms of recreational N₂O use. There was limited reference to policy or legislative responses in any published studies, no suggestions for harm reduction strategies or application of service level responses. In general, individuals lack awareness of N₂O-related harms.

CONCLUSION

The review found three key areas that deserve further consideration including: (1) policy, (2) service delivery, and (3) harm associated with N₂O use. We recommend a top-down (policy) and bottom-up (services delivery/services users) approach to harm reduction for N₂O use which also includes further consultation and research with both groups. Future research could explore young people's experience of N₂O use including benefits and problems to inform contextually relevant harm reduction strategies.

Massive Iatrogenic Pediatric Ketamine Overdose With Serial Levels and Minimal Morbidity

ABSTRACT

Ketamine is a dissociative anesthetic commonly used for procedural sedation owing to its perceived favorable safety profile. Despite its frequent use, overdoses of ketamine are rarely reported, and no cases with serum levels of ketamine or its metabolite have previously been reported. We report a case of an iatrogenic pediatric ketamine 20 mg/kg intramuscular overdose with serial ketamine and norketamine levels that resulted in minimal toxicity.

Anterior mediastinal masses - A multidisciplinary pathway for safe diagnostic procedures

OBJECTIVE

The objective of this study was to report our multidisciplinary diagnostic approach for patients with anterior mediastinal masses (AMM).

METHODS

A retrospective review of patients with AMM at a tertiary pediatric surgical oncology centre (January 2011-December 2016) was performed. We analyzed data on clinical presentation, mode of tissue diagnosis, anesthetic techniques, and complications.

RESULTS

Of the 44 patients admitted with AMM (median age 11 years, 27 males and 17 females), 22 had respiratory symptoms. Imaging revealed tracheobronchial compression in 26 children. Twenty patients had a lymph node biopsy. Ten patients had image-guided core biopsy of the mediastinal mass, and 2 had mediastinoscopic biopsy of a paratracheal lymph node. One patient with likely recurrence of a relapsed metastatic ethmoid carcinoma did not have a biopsy. The diagnosis was made from alternative tissues, such as pleural fluid in 4 and peripheral blood in 7 patients. Twenty-five anesthetics were assessed, as 14 patients required no or only local anesthesia, and 5 had unavailable anesthetic notes. Eighteen of 25 patients were anesthetized maintaining spontaneous breathing, mostly by means of ketamine sedation. There were no major anesthetic complications.

CONCLUSION

Safe tissue diagnosis of anterior mediastinal masses can be obtained by a personalized multidisciplinary approach. Use of alternative tissues, local anesthesia, and ketamine sedation help minimize the need for general anesthesia, muscle paralysis, and controlled ventilation.

LEVEL OF EVIDENCE

IV (Case Series with no Comparison Group).

Anaesthesia in a Disaster Zone: A Report on the Experience of an Australian Medical Team in Banda Aceh following the ‘Boxing Day Tsunami’

We report on the experience of a 23-member Australian medical team in Banda Aceh, Indonesia, following the 2004 Boxing Day tsunami. Arriving 13 days after the tsunami that devastated the city, killed 100,000 of its inhabitants and injured thousands more, we carried out 130 surgical procedures in austere conditions over a 12-day period. Most surgery was peripheral, principally for plastic surgical or orthopaedic procedures to lower limb injuries. Intravenous ketamine anaesthesia was the technique of choice, with good surgical conditions and few significant side-effects.

Oral Ketamine or Midazolam or Low Dose Combination for Premedication in Children

This randomized controlled trial was designed to evaluate whether the combination of low dose oral midazolam (0.25 mg/kg) and low dose oral ketamine (3 mg/kg) provides better premedication than oral midazolam (0.5 mg/kg) or oral ketamine (6 mg/kg). Seventy-eight children of ASA physical status I or II scheduled for elective ophthalmic surgery were randomly divided into three groups and given premedication in the holding area 30 minutes before surgery. Two subjects from each group vomited the medication and were excluded, leaving 72 subjects for further analysis.

The onset of sedation was earlier in the combination group than the other two groups. At 10 minutes after premedication 12.5% in the combination group had an acceptable sedation score compared with none in the other two groups. After 20 minutes 54% in the combination group had an acceptable sedation score, 21% in the midazolam group and 16% in the ketamine group (P<0.05). There were no significant differences in the parental separation score, response to induction and emergence score. The mean time for best parental separation score was significantly less in the combination group (19±8 min) than either the midazolam (28±7) or ketamine (29±7 min) groups (P<0.05). Recovery was earlier in the combination group, as the time required to reach a modified Aldrete score of 10 was significantly less in the combination group (22±5 min) than in the oral midazolam (36±11 min) or ketamine (38±8 min) groups. The incidence of excessive salivation was significantly higher in the ketamine alone group (P<0.05). In conclusion, the combination of oral ketamine (3 mg/kg) and midazolam (0.25 mg/kg) has minimal side effects and gives a faster onset and more rapid recovery than ketamine 6 mg/kg or midazolam 0.5 mg/kg for premedication in children.

Do Anesthetic Techniques Influence the Threshold for Glomerular Capillary Hemorrhage Induced in Rats by Contrast-Enhanced Diagnostic Ultrasound?

OBJECTIVES

Glomerular capillary hemorrhage can be induced by ultrasonic cavitation during contrast-enhanced diagnostic ultrasound (US) exposure, an important nonthermal US bioeffect. Recent studies of pulmonary US exposure have shown that thresholds for another nonthermal bioeffect of US, pulmonary capillary hemorrhage, is strongly influenced by whether xylazine is included in the specific anesthetic technique. The objective of this study was to determine the influence of xylazine on contrast-enhanced diagnostic US-induced glomerular capillary hemorrhage.

METHODS

In this study, anesthesia with ketamine only was compared to ketamine plus xylazine for induction of glomerular capillary hemorrhage in rats by 1.6-MHz intermittent diagnostic US with a microsphere contrast agent (similar to Definity; Lantheus Medical Imaging, Inc, North Billerica, MA). Glomerular capillary hemorrhage was measured as a percentage of glomeruli with hemorrhage found in histologic sections for groups of rats scanned at different peak rarefactional pressure amplitudes.

RESULTS

There was a significant difference between the magnitude of the glomerular capillary hemorrhage between the anesthetics at 2.3 MPa, with 45.6% hemorrhage for ketamine only, increasing to 63.2% hemorrhage for ketamine plus xylazine (P < .001). However, the thresholds for the two anesthetic methods were virtually identical at 1.0 MPa, based on linear regression of the exposure response data.

CONCLUSIONS

Thresholds for contrast-enhanced diagnostic US-induced injury of the microvasculature appear to be minimally affected by anesthetic methods.

[Comparison of three different anesthesia procedures in calves with respect to possible pain-associated reactions]

The objective of this study was to compare the effects of three anaesthetic protocols with respect to possible pain-associated reactions: injection (INJE) with xylazine (0.2 mg/kg), ketamine (5 mg/kg) and local anaesthesia (procain 2%); a combination of injection and inhalation (KOMB) with xylazine (0.2 mg/kg), ketamine (2 mg/kg), and isoflurane (1.5-3.0 vol%); and inhalation with isoflurane (control group [o]) surgery. During the trial, the anaesthetic level was controlled, and signs of response to surgical stimulation or spontaneous movements, changes in heart rate, mean arterial pressure, plasma L-lactate and cortisol levels were recorded. The dosage of 5 mg ketamine/kg body mass was rarely sufficient to obtain surgical tolerance in group INJE. In order to attain surgical tolerance, it was necessary to administer an average of 8.4 mg ketamine/kg body mass. All animals of the INJEc/o groups started to show signs of spontaneous movements or response to surgical stimulation between five and twelve minutes after the last administration of ketamine. Signs of response to surgical stimulation at the time of skin incision were significantly most frequent (37%) in the INHAc group, while agitation or response to surgical stimulation at least once during the entire time of anaesthesia was significantly (p <0.01) most frequent in the INJEc group (100%). Changes in heart rate and mean blood pressure were not found to be related to surgical stress situations.Ten minutes after the incision, the highest increases in plasma cortisol levels above basal levels of the previous day were determined in the groups INJEc and INJEo (53.5 and 57.7 nmol/l, respectively). However, a significant increase of plasma cortisol levels between the previous day and ten minutes after incision was only found between INHAc and INHAo (30.1 versus 7.5 nmol/l, p < 0.01) but not in the other pairs of groups (INJEc/o and KOMBdc/o). Within the three experimental groups the increase of plasma cortisol levels between the previous day and ten minutes after incision was only significant between INJEc and KOMBc (53.5 versus 28.3 nmol/l, p < 0.01). Among the protocols tested in this study, the combination anaesthesia (KOMB) was associated with the least amount of pain-associated reactions by the calves. Therefore, this protocol should be used preferred to the other two protocols in order to minimise stress and pain for the animals as much as posssible.

[Evaluation of perioperative analgesia by nociceptive flexor reflex in pigs under ketamine-azaperone-general anaesthesia]

The objective of the investigation was to evaluate quantitatively the analgesic efficacy of the Ketamine-Azaperone-general anesthesia during surgical procedures on pigs by nociceptive flexor reflexes (NFR). The study was performed in 30 four to five month old male pigs which were castrated. The NFR was evoked every minute over the N. ulnaris by multiple electrical stimulation consisting of five single stimuli (2 Hz). The reflex response was derived electromyographically (EMG) by surface electrodes placed over the M. deltoideus. The root-mean-square amplitude within the time interval of 80-240 ms after the last stimulus was calculated as measure for the reflex size. The threshold was fixed at 40 microV. Beside electrical NFR recording the surgical tolerance was determined by the traditional interdigital reflex and the defense reaction to defined surgical test stimuli which were incisisions in the scrotal skin, in the tunica vaginalis and in the testis, pulling off the spermatic cord, clamping and cutting off the spermatic cord and final wound disinfection. All surgical pain stimuli were performed simultaneously with the electrical stimuli. After induction of anesthesia the NFR amplitude declined from 3500 microV below the threshold of 40 microV. At 98% of the surgical stimuli without defense reaction were below the reflex threshold. At 93% with defense reactions demonstrated reflex amplitudes above the threshold. When the interdigital reflex was suppressed, 89% of the NFR values fell below the threshold of 40 microV. These findings demonstrate a good correlation of NFR-amplitudes with reactions to traditional controls of analgesia.

Anaesthesia for endoscopic retrograde cholangiopancreatography

Endoscopic Retrograde Cholangiopancreatography is used for both diagnostic and therapeutic purposes. It is relatively more complex than routine endoscopies and requires adequate patient sedation. Furthermore the patients often have co-morbidities. This article provides an overview of various anaesthetic drugs and the type of anaesthesiological support.

Reliability of distortion-product otoacoustic emissions in the common marmoset (Callithrix jacchus)

This study examines the test-retest reliability of distortion-product otoacoustic emissions (DPOAEs) in ketamine-anesthetized common marmosets (Callithrix jacchus). DPOAE gain functions were measured at 16 f(2)-frequencies between 3 and 24 kHz. Test-retest reliability was assessed at the following time intervals: (1) Interleaved, in which two gain functions were obtained at each frequency before advancing to the next frequency, (2) Immediate, wherein one gain function was collected at all f(2)-frequencies and the retest was immediately performed without removing the probe tip, (3) Short-term, in which the retest followed a 10-min period with the probe removed, and (4) Long-term, wherein the retest was performed at least one week after the initial test. Reliability was assessed using four correlation coefficients used in the literature. Test-retest reliability was best in the interleaved interval and worst in the short-term interval. In general, reliability was best when primary-tone levels were high. Correlation coefficients decreased at frequencies above 12-kHz in the short-term and long-term intervals, but the decrease was more substantial in females than in males in the long-term interval. At frequencies below 12 kHz, same-day measurements (2, 3) were less repeatable, regardless of whether the probe was removed, which may be due to time under anesthesia. These results have implications for DPOAE studies where repeated measures are required and when treatment or group differences are small.

Characterization of cardiac time intervals in healthy bonnet macaques (Macaca radiata) by using an electronic stethoscope

Nonhuman primates are used frequently in cardiovascular research. Cardiac time intervals derived by phonocardiography have long been used to assess left ventricular function. Electronic stethoscopes are simple low-cost systems that display heart sound signals. We assessed the use of an electronic stethoscope to measure cardiac time intervals in 48 healthy bonnet macaques (age, 8±5 y) based on recorded heart sounds. Technically adequate recordings were obtained from all animals and required 1.5±1.3 min. The following cardiac time intervals were determined by simultaneously recording acoustic and single-lead electrocardiographic data: electromechanical activation time (QS1), electromechanical systole (QS2), the time interval between the first and second heart sounds (S1S2), and the time interval between the second and first sounds (S2S1). QS2 was correlated with heart rate, mean arterial pressure, diastolic blood pressure, and left ventricular ejection time determined by using echocardiography. S1S2 correlated with heart rate, mean arterial pressure, diastolic blood pressure, left ventricular ejection time, and age. S2S1 correlated with heart rate, mean arterial pressure, diastolic blood pressure, systolic blood pressure, and left ventricular ejection time. QS1 did not correlate with any anthropometric or echocardiographic parameter. The relation S1S2/S2S1 correlated with systolic blood pressure. On multivariate analyses, heart rate was the only independent predictor of QS2, S1S2, and S2S1. In conclusion, determination of cardiac time intervals is feasible and reproducible by using an electrical stethoscope in nonhuman primates. Heart rate is a major determinant of QS2, S1S2, and S2S1 but not QS1; regression equations for reference values for cardiac time intervals in bonnet macaques are provided.

Glutamate transporter type 3 knockout mice have a decreased isoflurane requirement to induce loss of righting reflex

Excitatory amino acid transporters (EAAT) uptake extracellular glutamate, the major excitatory neurotransmitter in the brain. EAAT type 3 (EAAT3), the main neuronal EAAT, is expressed widely in the CNS. We have shown that the volatile anesthetic isoflurane increases EAAT3 activity and trafficking to the plasma membrane. Thus, we hypothesize that EAAT3 mediates isoflurane-induced anesthesia. To test this hypothesis, the potency of isoflurane to induce immobility and hypnosis, two major components of general anesthesia, was compared in the CD-1 wild-type mice and EAAT knockout mice that had a CD-1 strain gene background. Hypnosis was assessed by loss of righting reflex in this study. The expression of EAAT1 and EAAT2, two widely expressed EAATs in the CNS, in the cerebral cortex and spinal cord was not different between the EAAT3 knockout mice and wild-type mice. The concentration required for isoflurane to cause immobility to painful stimuli, a response involving primarily reflex loops in the spinal cord, was not changed by EAAT3 knockout. However, the EAAT3 knockout mice were more sensitive to isoflurane-induced hypnotic effects, which may be mediated by hypothalamic sleep neural circuits. Interestingly, the EAAT3 knockout mice did not have an altered sensitivity to the hypnotic effects caused by ketamine, an i.v. anesthetic that is a glutamate receptor antagonist and does not affect EAAT3 activity. These results suggest that EAAT3 modulates the sensitivity of neural circuits to isoflurane. These results, along with our previous findings which suggests that isoflurane increases EAAT3 activity, indicate that EAAT3 may regulate isoflurane-induced behavioral changes, including anesthesia.

Anticholinergics and ketamine sedation in children: a secondary analysis of atropine versus glycopyrrolate

OBJECTIVES

Adjunctive anticholinergics are commonly administered during emergency department (ED) ketamine sedation in children under the presumption that drying oral secretions should decrease the likelihood of airway and respiratory adverse events. Pharmacologic considerations suggest that glycopyrrolate might exhibit a superior adverse effect profile to atropine. The authors contrasted the adverse events noted with use of each of these anticholinergics in a large multicenter observational database of ketamine sedations.

METHODS

This was a secondary analysis of an observational database of 8,282 ED ketamine sedations assembled from 32 prior series. The authors compared the relative incidence of six adverse events (airway and respiratory adverse events, laryngospasm, apnea, emesis, recovery agitation, and clinically important recovery agitation) between children who received coadministered atropine, glycopyrrolate, or no anticholinergic. Multivariable analysis using the specific anticholinergic as a covariate was performed, while controlling for other known predictors.

RESULTS

Atropine was associated with less vomiting (5.3%) than either glycopyrrolate (10.7%) or no anticholinergic (11.4%) in both unadjusted and multivariable analyses. Glycopyrrolate was associated with significantly more airway and respiratory adverse events (6.4%) than either atropine (3.3%) or no anticholinergic (3.0%) and similarly more clinically important recovery agitation (2.1% vs. 1.2 and 1.3%). There were, however, no differences noted in odds of laryngospasm and apnea.

CONCLUSIONS

This secondary analysis unexpectedly found that the coadministered anticholinergic atropine exhibited a superior adverse event profile to glycopyrrolate during ketamine sedation. Any such advantage requires confirmation in a separate trial; however, our data cast doubt on the traditional premise that glycopyrrolate might be superior. Further, neither anticholinergic showed efficacy in decreasing airway and respiratory adverse events.

[Anesthetic management during cardiac bypass in fetal lambs]

OBJECTIVE

To summarize the anesthetic management in fetal lamb cardiac bypass.

METHODS

Five ewes at 120-140 days of gestation were anesthetized intramuscularly with katamine hydrochloride, intubated and ventilated with a respirator. Anesthesia was maintained with fentanyl and vecuronium. Lactated Ringer's solution and magnesium sulfate were infused to maintain the mean blood pressure (MAP) over 70 mmHg and uterine relaxation. The fetal lambs received anesthesia with fentanyl and vecuronium intramuscularly via the uterine wall. Fetal cardiac bypass was established with pulmonary artery and right atrium cannulation, lasting for 30 min. The hemodynamic and blood gas data of the ewes and fetal lambs were recorded before bypass, at 30 min during bypass, and at 1 and 2 h after cessation of bypass. The pulse index of the umbilical artery (PIua) and the ewe's uterine artery (PIeu) were monitored simultaneously.

RESULTS

The MAP and heart rate (HR) of the fetus remained normal during the anesthesia. PIua increased significantly after cessation of bypass (P<0.05). Although the fetal oxygen tension in the axillary artery remained normal, the fetal lambs showed hypercarbia and acidosis after cessation of bypass (P<0.05). The maternal MAP and HR remained normal. The PIeu decreased significantly during bypass (P<0.05) and recovered the normal level after cessation of bypass. The arterial blood gas of the ewes was normal during the experiment.

CONCLUSION

Maintaining high hemodynamics in the ewes, application of uterine relaxation and intensive care during anesthesia are crucial in anesthetic management of cardiac bypass in fetal lambs.

Synthesis and structural assignment of two major metabolites of the LTA4H inhibitor DG-051

The same two major CYP mediated metabolites of DG-051 were produced in the presence of rat, dog, monkey and human liver microsomes. Their respective structures were hypothesized based on mass spectrometry data correlated with the parent structure and confirmed by comparison with authentic synthetic samples. The number of regioisomers synthesized as candidates for metabolite M1 was narrowed down using a metabolic study of a selectively deuterated DG-051 analogue.

Assessment of recovery, dreaming, hemodynamics, and satisfaction in postcardiac surgery patients receiving supplementary propofol sedation with S(+)-ketamine

BACKGROUND

S(+)-ketamine is an analgesic and sedative drug with dissociative attributes. When it is used without sedatives, nightmares have been described. The aim of this study was to assess the effects of postoperative analgosedation with propofol and S(+)-ketamine when compared to standard propofol analgosedation in terms of recovery, dreaming, hemodynamics, and patient satisfaction.

METHODS

Forty-eight patients were sedated with propofol (1-3 mg/kg/h) after coronary artery bypass grafting and allocated randomly on admission to the intensive care unit to receive either S(+)ketamine (2 mg mg/kg/h; group A) or 0.9% saline as a placebo (group B) in a double-blind fashion. If necessary, boli of 3.75 mg piritramide (an opioid) were given in both groups.

RESULTS

Patients receiving S(+)-ketamine had significantly higher satisfaction for pain management (Visual Analog Scale [VAS] = group A: median 10 [range 9-10]; group B: median 9 [range 6-10]) despite their lower piritramide consumption. Patients receiving S(+)ketamine showed significantly faster eye opening (82+/-51 vs 156+/-110 min) but dreamed significantly more often (at 2 h, 67% in group A vs 29% in group B; at 24 h, 43% in group A vs 10% in group B), whereas no significant differences were detected in the incidence of nightmares at 2 h, 14% in group A vs 10% in group B; at 24 h, 5% in group A vs 5% in group B.

CONCLUSIONS

Patients receiving S(+)-ketamine showed higher satisfaction for pain management and dreamed more often, but they did not have more nightmares.

[Effect of orexin-A on recovery from ketamine anesthesia in aged rats]

OBJECTIVE

To observe the effect of orexin-A on the recovery and cognitive function of aged rats after ketamine anesthesia.

METHODS

Fifty-five aged rats were divided randomly into control group, model control group, 1 nmol/L Orexin-A group, and 4 nmol/L Orexin-A group. In the latter 3 groups, the rats received an intraperitoneal injection of ketamine at 100 mg/kg, and normal saline was injected in the control group. Ten minutes after the injections, the rats received intraventricular injections of artificial cerebrospinal fluid (control and model control group) or of 10 microl 1 or 4 nmol/L Orexin-A as indicated. The behavioral changes of the rats were assessed by the duration of loss of righting reflex (LORR). Electroencephalogram (EEG) recordings were used to evaluate the changes in rat brain activity by comparison of the percent of sigma wave in EEG before and after the intraventricular injections. Morris water maze was used to test the learning and spatial localization abilities of the rats.

RESULTS

Ketamine resulted in obvious impairment of learning and memory abilities of the aged rats. Orexin-A at 4 nmol/L induced significant decrease in the duration of LORR and marked reduction of sigma activities in anesthetic rats (P<0.05), and obviously improved the learning and spatial localization abilities of the rats after anesthesia (P<0.05).

CONCLUSION

Orexin-A can promote the recovery and improve the cognitive function of aged rats after ketamine anesthesia.

Randomised, cross-over comparison of sevoflurane and ketamine-midazolam anaesthesia in children undergoing extracorporeal shock-wave lithotripsy

INTRODUCTION

The aim of this study was to assess the haemodynamic responses, adverse events and recovery characteristics associated with sevoflurane and ketamine-midazolam anaesthesia for paediatric extracorporeal shock-wave lithotripsy.

METHODS

Twenty children aged 2-11 years, who were undergoing two consecutive lithotripsy sessions at an interval of 4 weeks were enrolled and randomised to receive either inhalation or dissociative anaesthesia at their first session. The alternative anaesthesia protocol was used at their second session. Inhalation anaesthesia was induced with 8% sevoflurane and 70% N(2)O in oxygen; 10 microg/kg atropine and 2 microg/kg fentanyl were then administered. Anaesthesia was maintained with 2%-3% end-tidal sevoflurane and 70% N(2)O in oxygen via a laryngeal mask airway. Dissociative anaesthesia was induced intravenously with 10 mug/kg atropine, 0.05 mg/kg midazolam, 1.5 mg/kg ketamine and maintained with 0.5-1.0 mg/kg ketamine. Haemodynamic parameters were recorded before and after induction, after the start of the procedure, and every 10 minutes thereafter. Postoperatively, the times to responding to command, sitting, ambulating, achieving an Aldrete score > or = 9, and achieving a post-anaesthetic discharge score > or = 9 were recorded.

RESULTS

Systolic and diastolic arterial pressures at all measurements throughout the procedure were higher with ketamine-midazolam than with sevoflurane (P<0.05). Heart rates were comparable between groups, except after induction and after start of the procedure in which they were higher with ketamine-midazolam (P<0.05). All recovery endpoints were achieved earlier with sevoflurane than with ketamine-midazolam (P<0.05). Nausea-vomiting incidences were similar in both groups.

CONCLUSION

Sevoflurane and ketamine-midazolam both provided effective anaesthesia for paediatric lithotripsy. The recovery and discharge times were shorter after anaesthesia with sevoflurane compared with ketamine-midazolam in children undergoing lithotripsy.

Ketamine for emergency anaesthesia at very high altitude (4243 m above sea-level)

A 22-year-old woman presenting with postpartum haemorrhagic shock at 4243 m altitude required anaesthesia to identify and treat the source of bleeding. Slow intravenous administration of ketamine (0.5 mg x kg(-1)) resulted in deep anaesthesia and apnoea requiring hand ventilation for 5 min. Haemodynamic stability was maintained throughout the procedure. Haemostasis was achieved following uterine packing and suture of a second-degree vaginal tear and small cervical tear. Confusion and visual hallucinations occurred upon awakening but recovery was otherwise uneventful. Ketamine can be used for emergency anaesthesia in a wilderness environment over 4000 m but it is probable that the benefits outweigh the risks only where life or limb are acutely threatened. Careful titration of the administered dose is strongly advised, particularly in patients where hypovolaemia and/or hypoxaemia are present. The availability of airway management equipment and the skills to use them may significantly reduce the risks associated with anaesthetic administration at very high altitude.

Effects of Fentanyl and S(+)-ketamine on Cerebral Hemodynamics, Gastrointestinal Motility, and Need of Vasopressors in Patients With Intracranial Pathologies

In neurosurgical patients, opioids are administered to prevent secondary cerebral damage. Complications often related to the administration of opioids are a decrease in blood pressure affording the use of vasopressors and intestinal atonia. One alternative approach to opioids is the application of S(+)-ketamine. However, owing to a suspected elevation of intracranial pressure (ICP), the administration of S(+)-ketamine has questioned for a long time. The aim of the present study was to evaluate ICP, gastrointestinal motility, and catecholamine consumption in neurosurgical patients undergoing 2 different protocols of anesthesia using fentanyl or S(+)-ketamine. Twenty-four patients sustaining traumatic brain injury or aneurysmal subarachnoid hemorrhage received methohexitone plus either fentanyl or S(+)-ketamine to establish a comparable level of sedation. To reach an adequate cerebral perfusion pressure (CPP), the norepinephrine dosage was adapted successively. Enteral nutrition and gastrointestinal stimulation were started directly after admission on the critical care unit. ICP, CPP, and norepinephrine dosage were recorded over 5 days and also the time intervals to full enteral nutrition and first defecation. There was no difference regarding ICP, CPP, and the time period until full enteral nutrition or first defecation between both groups. Patients who underwent analgesia with S(+)-ketamine showed a trend to a lower demand of norepinephrine compared with the fentanyl group. Our results indicate that S(+)-ketamine does not increase ICP and that its use in neurosurgical patients should not be discouraged on the basis of ICP-related concerns.

Isoflurane is an effective alternative to ketamine/xylazine/acepromazine as an anesthetic agent for the mouse electroretinogram

The electroretinogram (ERG) is an essential measure of retinal function for studying mouse models of retinal disease. Ketamine, in combination with xylazine and/or acepromazine, is the most commonly used anesthetic agent. Although it works well in most situations, some fragile mouse strains have high mortality rates with this ketamine cocktail. We compared isoflurane with the ketamine cocktail in a longitudinal study of light-adapted and dark-adapted ERGs in C57BL/6J mice. Waveforms were averaged, oscillatory potentials (OPs) were extracted by digital filtration, and key ERG parameters were analyzed. The ERG waveforms were qualitatively similar with both anesthetics, and the male and female ERG parameters did not show significant differences. For light-adapted ERGs, b-wave amplitude and implicit time, and wavelet index were decreased under isoflurane anesthesia, whereas for dark-adapted ERGs, a- and b-wave implicit times were decreased and wavelet index was increased. The dark-adapted b-wave amplitude showed a significant inverse correlation with animal weight and age. Rod phototransduction gain and the Naka-Rushton n and R (max) parameters were the same for both anesthetics, and only the Naka-Rushton log k parameter was significantly elevated for isoflurane anesthesia. We propose that isoflurane is a satisfactory alternative to the ketamine cocktail for anesthesia in the mouse ERG. Precise quantitative comparisons, however, should only employ study designs using isoflurane versus isoflurane, or ketamine versus ketamine. Moreover, in light of the effects of both isoflurane and the ketamine cocktail on blood glucose levels, it would be prudent to control the fasting state of the animals in quantitative ERG studies.

Intranasal midazolam Vs ketamine as premedication in paediatric surgical procedure for child separation and induction

In children pre-anaesthetic medications are frequently administered as pharmacological adjunctions to help alleviate the stress and fear of surgery as well as to ease child parental separation and promote a smooth induction. Oral, rectal, intravenous and intramuscular route has been used; however each route has its disadvantage. Pre-anaesthetic medication administered intranasal for avoidance of painful injection have made it a convenient way to pre-medication. To evaluate the efficacy of intranasal administered Midazolam 0.2 mg/kg and Ketamine 5 mg/kg respectively. Total 50 patients of ASA I and II of age group 1- 7 years, mean age 3.88 +/- 1.26 and 4.56 +/- 1.21 were included in group I and group II respectively, and Scheduled for elective surgery. Mean time of separation was 17.12 +/- 1.21 in-group I and 15.68+11.62 in group II with P value < 0.001 and 0.322, shows significant difference during time of separation from parents and no significant difference for i.v. line insertion in both groups.

Effect of intraocular surgery and ketamine on aqueous and serum cytokines

PURPOSE

To determine the effect of intraocular surgery and anesthesia on aqueous and serum cytokines.

METHODS

Patients undergoing routine cataract surgery under general and local (peribulbar) anesthesia were randomized to those given general anesthetic with and without the use of ketamine and those having local anesthesia. Aqueous and serum levels of cytokines were collected at commencement of surgery and were determined by an immunoassay using multi-analyte biochip array technology at 18 h post-operatively.

RESULTS

At 18 h postoperative, all patients (37) showed significant and many fold increases in their aqueous levels of interleukin (IL)-1alpha, IL-1beta, IL-4, IL-6, IL-8, vascular endothelial growth factor (VEGF), tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, epidermal growth factor (EGF), and monocyte chemotactic protein (MCP)-1. There was little to no increase in IL-2 and IL-10. Significant increases in some cytokines (EGF, IL-6, and IFN-gamma) in the serum were also found (p=0.038). There were no significant differences in aqueous cytokine levels following the use of ketamine or between those patients who had general and local anesthesia (0.11<p<0.97).

CONCLUSIONS

There is an aqueous and serum cytokine response following intraocular surgery whether local (peribulbar) or general anesthesia is used. Of the aqueous cytokines measured, three different patterns of responses emerged at 18 h post-cataract surgery; those that were highly increased (IL-8, IL-6, IFN-gamma, and TNF-alpha), medium increase (IL-1beta, VEGF, IL-4, and MCP-1), and those with little to no change (EGF, IL-1alpha, IL-2, and IL-10).

Premedication of the pediatric patient – anesthesia for the uncooperative child

PURPOSE OF REVIEW

Inadequate handling of an uncooperative child preoperatively results in postoperative behavior problems. Premedication enables a calm induction and helps to decrease postoperative problems. Several premedicants will be covered in this review.

RECENT FINDINGS

Questions raised about the effects of oral midazolam use in children for premedication are now finding answers. New agents (dexmedetomidine and atypical antipsychotic agents) can be alternatives in premedication, especially in severely uncooperative children. The current literature highlights the missing information about the rather older premedicants.

SUMMARY

The benefits and disadvantages of new and older drugs should be weighed against each other, and decisions should be made according to the requirements of surgery, ward conditions and the severity of psychologic, developmental or mental disease. Further studies for the evaluation of the anxiolytic, sedative and antipsychotic drugs are still required.

Patterns of ketamine use among young injection drug users

Ketamine is a dissociative anesthetic that has emerged as an increasingly popular choice among young drug users. Recent research indicates the presence of hidden populations of young people who inject ketamine in New York and other U.S. cities. Applying an ethno-epidemiological approach, the authors recruited 40 young injection drug users (IDUs) (< 25 years old) in New York City to explore health risks associated with ketamine use. This analysis looks at the varying patterns and frequencies of ketamine injection by examining personal, social, and cultural aspects of these young people's lives. We learned that drug-using histories, experiential dimensions, sociocultural characteristics, and associations with other young people help account for the different patterns of injecting ketamine within the sample. In particular, these findings indicate that young people who were more frequent ketamine injectors had the following characteristics: initiated injection drug use with ketamine; enjoyed the effects of ketamine, were stably housed; lived in the vicinity of New York City; and associated with others who also injected ketamine.

Interactions between cardiac, respiratory and EEG-delta oscillations in rats during anaesthesia

We hypothesized that, associated with the state of anaesthesia, characteristic changes exist in both cardio-respiratory and cerebral oscillator parameters and couplings, perhaps varying with depth of anaesthesia. Electrocardiograms (ECGs), respiration and electroencephalograms (EEGs) were recorded from two groups of 10 rats during the entire course of anaesthesia following the administration of a single bolus of ketamine-xylazine (KX group) or pentobarbital (PB group). The phase dynamics approach was then used to extract the instantaneous frequencies of heart beat, respiration and slow delta-waves (within 0.5-3.5 Hz). The amplitudes of delta- and theta-waves were analysed by use of a time-frequency representation of the EEG signal within 0.5-7.5 Hz obtained by wavelet transformation, using the Morlet mother wavelet. For the KX group, where slow delta-waves constituted the dominant spectral component, the Hilbert transform was applied to obtain the instantaneous delta-frequency. The theta-activity was spread over too wide a spectral range for its phase to be meaningfully defined. For both agents, we observed two distinct phases of anaesthesia, with a marked increase in theta-wave activity occurring on passage from a deeper phase of anaesthesia to a shallower one. In other respects, the effects of the two anaesthetics were very different. For KX anaesthesia, the two phases were separated by a marked change in all three instantaneous frequencies: stable, deep, anaesthesia with small frequency variability was followed by a sharp transition to shallow anaesthesia with large frequency variability, lasting until the animal awoke. The transition occurred 16-76 min after injection of the anaesthetic, with simultaneous reduction in the delta-wave amplitude. For PB anaesthesia, the two epochs were separated by the return of a positive response to the pinch test at 53-94 min, following which it took a further period of 45-70 min for the animal to awaken. delta-Waves were not apparent at any stage of PB anaesthesia. We applied non-linear dynamics and information theory to seek evidence of causal relationships between the cardiac, respiratory and slow delta-oscillations. We demonstrate that, for both groups, respiration drives the cardiac oscillator during deep anaesthesia. During shallow KX anaesthesia the direction either reverses, or the cardio-respiratory interaction becomes insignificant; in the deep phase, there is a unidirectional deterministic interaction of respiration with slow delta-oscillations. For PB anaesthesia, the cardio-respiratory interaction weakens during the second phase but, otherwise, there is no observable change in the interactions. We conclude that non-linear dynamics and information theory can be used to identify different stages of anaesthesia and the effects of different anaesthetics.

Control of shivering during regional anaesthesia: prophylactic ketamine and granisetron

BACKGROUND

The aim of the present study was to compare placebo, ketamine, granisetron and a combination of ketamine and granisetron in the prevention of shivering caused by regional anaesthesia.

METHODS

In this prospective, randomized, double-blind study, 160 ASA I and II patients undergoing urological surgery were included. Subarachnoid anaesthesia was performed in all patients with bupivacaine 15 mg. The patients were randomly allocated to receive saline (group P, n= 40), ketamine 0.5 mg (group K, n= 40), granisetron 3 mg (group G, n= 40) or ketamine 0.25 mg + granisetron 1.5 mg (group KG, n= 40). Shivering was graded as 0 = no shivering, 1 = piloerection or peripheral vasoconstriction but no visible shivering, 2 = muscular activity in only one muscle group, 3 = muscular activity in more than one muscle group but not generalized, and 4 = shivering involving the whole body. If 15 min after spinal anaesthesia and concomitant administration of a prophylactic dose of one of the study drugs, the patients shivered according to at least grade 3, the prophylaxis was regarded as ineffective and intravenous (i.v.) pethidine 25 mg was administered.

RESULTS

After 15 min, the number of patients with observed shivering was 22 in group P, 6 in group G, 7 in group GK and 0 in group K. The difference between group K and all the other groups was statistically significant (P < 0.0001). The number of patients with a shivering score of 3 was statistically significantly higher in group P compared with the other groups.

CONCLUSION

The prophylactic use of 0.5 mg/kg i.v. ketamine was effective in preventing shivering developed during regional anaesthesia.

The effects of ketamine and rocuronium on the A-Line auditory evoked potential index, Bispectral Index, and spectral entropy monitor during steady state propofol and remifentanil anesthesia

BACKGROUND

The authors studied the effects of ketamine and rocuronium on the Bispectral Index, A-Line auditory evoked potential index, state entropy, and response entropy during a calculated steady state anesthesia with propofol and remifentanil.

METHODS

After ethics committee approval, 42 patients were allocated to four groups. Baseline measurements were performed after implementing a calculated steady state anesthesia with propofol and remifentanil. The control group received no additional medication. The ketamine group received a bolus and continuous infusion of ketamine. The rocuronium group received a bolus of rocuronium. The rocuronium-ketamine group received both. All data were stored during 15 min after baseline. After inspection of the raw data, the authors conducted an explorative statistical analysis.

RESULTS

No significant changes were found in the control group for any of the monitors. Mean values decreased in the rocuronium group for the A-Line auditory evoked potential index, Bispectral Index, and response entropy, but not for state entropy. In the ketamine group, the A-Line auditory evoked potential index and Bispectral Index did not change significantly, but state and response entropy increased. In the rocuronium-ketamine group, the A-Line auditory evoked potential index and Bispectral Index did not decrease as found in the rocuronium group. Response and state entropy increased significantly.

CONCLUSIONS

The response of all monitors after ketamine administration is not affected by simultaneous administration of rocuronium. Interpretation of all studied indices must be done cautiously while taking into account the clinical setting during measurement.

Earthquake injuries and the use of ketamine for surgical procedures: the Kashmir experience

The October 8, 2005 earthquake in Northern Pakistan had widespread destructive effects throughout the northern subcontinent. Large numbers of people were killed or severely injured and many medical services destroyed. This report describes the experience of the only standing surgical hospital in the Kashmir region of Bagh District. More than 1,500 people were triaged in 72 hours, many critically injured; 78.4% of patients had upper or lower limb injuries; 50.3% of patients had fractures, mainly closed; 37% of patients required extensive wound debridements. A total of 149 patients received emergency surgery using ketamine anaesthesia with benzodiazepine premedication. This was found to be safe, effective and with a low incidence of major adverse effects. We recommend that ketamine anaesthesia be encouraged in disaster area surgery, particularly in under-resourced regional centres.