Transient abdominal wall deformity in an infant Blaming the caudal?

Locoregional anesthesia is an important aspect of perioperative analgesia. It decreases requirements for anesthetic agents and opioids, decreases the surgical stress response, and provides postoperative analgesia. Nonetheless, pediatric patients, especially infants, demonstrate specificities towards regional anesthesia techniques, as an increased sensitivity to local anesthetics (LA) and a higher ease of LA spread especially when using blocks that rely on the volume of LA and its spread as those used for abdominal wall analgesia or caudal. Thus, we present a case of transient abdominal wall deformity following caudal anesthesia in an infant.     

国内大型综合医院和儿童医院小儿术后镇痛调查

目的了解当今国内小儿术后镇痛工作在儿童手术量较大的大型综合医院和儿童医院的应用情况,为小儿术后镇痛在国内推广应用提供参考。方法对全国预计小儿麻醉年手术量超过1000例的40家医院的麻醉科进行了问卷调查。31家医院完成调查,剔除年小儿手术量低于1000例的4家,纳入27家医院进行分析。调查的内容包括医院镇痛管理相关政策和制度,小儿术后镇痛开展情况,如开展镇痛的年龄段、常用术后镇痛方式和药物、静脉镇痛泵配方、小儿术后镇痛存在的问题等。结果纳入分析的医院中88．9％开展了小儿术后镇痛工作,开展1岁～3岁幼儿术后镇痛的占81．5％,1个月-12个月婴儿术后镇痛的占55．6％,新生儿术后镇痛仅有25．9％。超过80％的医院建立了小儿术后镇痛相关培训,并有个性化镇痛方案和疗效评估,但只有59．3％的医院安排有专门的小儿术后镇痛人员,22．2％设置了术后镇痛服务小组。所有开展小儿术后镇痛的医院均使用静脉患者自控镇痛（patient controlled analgesia,PCA）,只有25．9％医院开展硬膜外PCA方式镇痛。局麻药被广泛用于小儿术后镇痛,包括罗哌卡因、利多卡因和布比卡因,阿片类药物以舒芬太尼、芬太尼和曲马多为主,经常使用非甾体类抗炎药（non-steroid anti-inflammatory drugs,NSAIDs）的医院仅占29．6％,只有11．1％的医院经常使用对乙酰氨基酚。结论小儿术后镇痛工作在我国儿童手术较多的大型综合性医院和儿童医院已经普遍开展,但婴儿和新生儿的术后镇痛工作有待加强。有必要普及术后切口局麻药浸润,更多开展外周神经阻滞;普及副作用少又经济实用的对乙酰氨基酚类药物的使用,增加NSAIDs的用量,加强阿片类药物治疗安全的监控。     

Opioids as local anesthetic adjuvants for peripheral nerve block

Although the perineural application of opioids with local anesthetics has been of interest to anesthesiologists for years, neither the theoretical mechanism of action nor the effectiveness of this technique have been established. Opioid receptors are evident in the dorsal root ganglia (DRG), and central and peripheral endings of sensory afferents. Inflammation dramatically increases the production and axonal transport of these receptors. Local opioid injection in inflamed tissue is antinociceptive. Nevertheless, there is no evidence of opioid receptors in axonal membranes of afferent nerves in the portions of the axon where regional anesthesia is typically induced. Peripheral opioid injection produces modest analgesia in surgical patients when injected intraarticularly, and prolonged analgesia when injected locally into inflamed dental tissues, but has no effect in the absence of inflammation. Animal studies of perineural opioid application, in typical clinical concentrations, have shown no effect on sensory nerve action potentials. In the setting of acute, postoperative pain, the weight of evidence is against a significant clinical benefit from the addition of morphine, fentanyl, or sufentanil to local anesthetics for peripheral nerve block. Positive studies have often used injection sites close to the neuraxis or have not included systemic control groups. In a limited number of studies, perineural buprenorphine has produced prolonged analgesia. Basic opioid receptor research may ultimately provide a mechanism for perineural opioid activity. Alternatively we may determine that including opioids with local anesthetics for regional anesthesia is illogical and ineffective.     

The blood/gas solubilities of sevoflurane, isoflurane, halothane, and serum constituent concentrations in neonates and adults

To determine the effect of prematurity on the solubility of volatile anesthetics in blood, the authors measured the blood/gas partition coefficients of sevoflurane, isoflurane, and halothane and the serum concentrations of albumin, globulin, cholesterol, and triglycerides in umbilical venous blood from ten preterm and eight full-term neonates and in venous blood from eight fasting adult volunteers. The authors found that the blood/gas partition coefficient of sevoflurane did not differ significantly among the three age groups. The partition coefficients of isoflurane and halothane in preterm neonates did not differ significantly from those in full-term neonates. However, the partition coefficients of both anesthetics in neonates were significantly less than those in adults. The blood/gas partition coefficients of the three volatile anesthetics in preterm neonates did not change significantly with gestational age. The blood/gas partition coefficients of sevoflurane, isoflurane and halothane for all three age groups combined correlated only with the serum concentration of cholesterol. The authors conclude that the blood/gas partition coefficients of isoflurane, halothane, and sevoflurane in preterm neonates are similar to those in full term neonates and that gestational age does not significantly affect the blood/gas solubility.     

Anästhesie und Analgesie bei Suchtpatienten

Addicts have an exaggerated organic and psychological comorbidity and in cases of major operations or polytrauma they are classified as high-risk patients. Additional perioperative problems are a higher analgetics requirement, craving, physical and/or psychological withdrawal symptoms, hyperalgesia and tolerance. However, the clinical expression depends on the substance abused. For a better understanding of the necessary perioperative measures, it is helpful to classify the substances into central nervous system depressors (e.g. heroin, alcohol, sedatives, hypnotics), stimulants (e.g. cocaine, amphetamines, designer drugs) and other psychotropic substances (e.g. cannabis, hallucinogens, inhalants). The perioperative therapy should not be a therapy for the addiction, as this is senseless. On the contrary, the characteristics of this chronic disease must be accepted. Anesthesia and analgesia must be generously stress protective and sufficiently analgesically effective. Equally important perioperative treatment principles are stabilization of physical dependence by substitution with methadone (for heroin addicts) or benzodiazepines/clonidine (for alcohol, sedatives and hypnotics addiction), avoidance of stress and craving, thorough intraoperative and postoperative stress relief by using regional techniques or systematically higher than normal dosages of anesthetics and opioids, strict avoidance of inadequate dosage of analgetics, postoperative optimization of regional or systemic analgesia by non-opioids and coanalgetics and consideration of the complex physical and psychological characteristics and comorbidities. Even in cases of abstinence (clean) an inadequate dosage must be avoided as this, and not an adequate pain therapy sometimes even with strong opioids, can potentially activate addiction. A protracted abstinence syndrome after withdrawal of opioids can lead to increased response to administered opioids (e.g. analgesia, side-effects).     

Drug choices for intravenous and spinal analgesia

Opioids remain at the center of most postoperative pain control therapies. The choice between full agonist opioids should be determined by the time for a given dose to produce its maximum effect (i.e., latency to peak effect), and the duration of action. There is little to choose between different opioids administered by patient-controlled analgesia. Parenterally-administered NSAIDs (e.g., ketorolac) contribute significantly to analgesia and reduce opioid requirements. Morphine may be the opioid of choice for epidural administration. The combination of epidural opioids and local anesthetics provides synergistic analgesia and appears to provide superior analgesia with activity. Several nonopioid receptor agonists are under investigation as neuraxial analgesics.     

Repair of duodenal atresia under spinal anesthesia in a low-birth-weight preterm neonate: case report

Duodenal atresia is a well-recognized cause of neonatal bowel obstruction. General anesthesia with tracheal intubation is the traditional anesthetic technique for surgical correction of this condition. Metabolic abnormalities and fluid deficits coupled with residual anesthetics are known to increase the risk of postoperative apnea, prolonging the operating room time and delaying extubation. Spinal anesthesia (SA) is an accepted alternative to general anesthesia in formerly preterm infants. In the current literature, there are reports of successful use of SA for simple infraumbilical surgery and, occasionally, for upper abdominal surgery, but there is no information on the use of SA in neonates for duodenal atresia repair. We present a case of duodenal atresia in a preterm infant at a gestational age of 30 weeks with coexisting bronchopulmonary dysplasia successfully repaired under SA. Further studies that compare the adverse effects with the potential advantages of SA are warranted before future recommendations are made for neonates who are undergoing upper abdominal surgery.     

Schmerztherapie nach wirbelsäulenchirurgischen Eingriffen

A dorsal approach during spinal surgery offers the possibility to distribute drugs directly to the nerve root or epidurally. This can be done via a single intraoperative dose or by placing an epidural catheter. A safe and effective analgesia can thereby be achieved. As placement is done under visual control, no major complications are to be expected. In nerve root compressions, additional local application of steroids and preoperative gabapentin seems sensible. No advantage of preemptive administration of other analgesics can be determined. Another problem, especially of ventral fusions, is the commonly needed autologous pelvic bone grafts. Here the local application of local anesthetics or opioids makes sense. In transthoracic approaches epidural analgesia is recommended by thoracic surgeons, but this is difficult to perform especially in children with deformities. Furthermore it is generally important not to compromise neuralgic controls by analgesic measures.     

Clonidine in preterm-infant caudal anesthesia may be responsible for postoperative apnea

OBJECTIVE: Regional anesthesia without adjunctive general anesthesia or sedation has been recommended for preterm infants to decrease the risk of postoperative apnea. Single-dose caudal local anesthetic has a limited duration, which may be insufficient for long surgery. Addition of clonidine to local anesthetics has been shown to prolong the duration of surgical analgesia. However, respiratory depression related to clonidine may occur in adults. Respiratory depression has not been reported after caudal administration of clonidine in preterm infants. Here we report a case of early postoperative apnea in a waking preterm infant after caudal anesthesia performed with lidocaine, bupivacaine, and clonidine. CASE REPORT: A male infant, 39 postconceptual weeks old, was administered a single-injection caudal anesthesia without sedation with 5 mg/kg lidocaine plus 2.5 mg/kg bupivacaine and 1.25 microg/kg clonidine for bilateral inguinal hernia repair, and had early postoperative apneic events. Except for gestational age, the patient showed no apparent risk factors for postoperative apnea. The infant was monitored 24 hours in a neonatal intensive care unit, and no other apnea was recorded. CONCLUSIONS: Our report suggests that clonidine may be responsible for postoperative apnea in a preterm neonate. Further studies are required to determine the useful safe dose of clonidine for single-injection caudal anesthesia in those infants.     

A randomized multicenter study of remifentanil compared with halothane in neonates and infants undergoing pyloromyotomy. II. Perioperative breathing patterns in neonates and infants with pyloric stenosis.

Although former preterm birth infants are at risk for postoperative apnea after surgery, it is unclear whether the same is true of full-term birth infants. We evaluated the incidence of apnea in 60 full-term neonates and infants undergoing pyloromyotomy both before and after anesthesia. All subjects were randomized to a remifentanil- or halothane-based anesthetic. Apnea was defined by the presence of prolonged apnea (>15 s) or frequent brief apnea, as observed on the pneumocardiogram. Apnea occurred before surgery in 27% of subjects and after surgery in 16% of subjects, with no significant difference between subjects randomized to remifentanil or halothane anesthesia. This apnea was primarily central in origin, occurred throughout the recording epochs, and was associated with severe desaturation in some instances. Of the subjects with normal preoperative pneumocardiograms, new onset postoperative apnea occurred in 3 (23%) of 13 subjects who received halothane-based anesthetics versus 0 (0%) of 22 subjects who received remifentanil-based anesthetics (P = 0.04). Thus, postoperative apnea can follow anesthesia in otherwise healthy full-term infants after pyloromyotomy and is occasionally severe with desaturation. New-onset postoperative apnea was not seen with a remifentanil-based anesthetic. IMPLICATIONS: Abnormal breathing patterns can follow anesthesia in infants after surgical repair of pyloric stenosis. Occasionally, these patterns can be associated with desaturation. New-onset postoperative apnea was not seen with a remifentanil-based anesthetic.     

Perioperative Schmerztherapie bei opioidgewöhnten Patienten

In this review article the special anesthesiological problems of opioid tolerance and surgical interventions will be presented. These affect patients with a long-term opioid therapy of chronic pain, addicts with long-term substitution therapy and addicts with current or previous heroin addiction (“clean”). For all patient groups a guarantee of continuous and adequate analgesia (avoidance of fear and increasing patient compliance), exploiting suitable regional anesthesia or regional analgesia procedures when possible, and prevention of a physical opioid withdrawal syndrome have utmost priority. The necessary optimization of perioperative pain therapy only succeeds when based on a thorough preoperative examination of the clinical history which subtly inquires into the drug taking habits with respect to opioids and associated medications. Systemic and/or regional analgesia procedures are possible. Regional procedures are more effective for analgesia. Systemic analgesia procedures do not basically differ from those routinely used for patients without opioid tolerance. However, higher doses of opioids are necessary as well as individual titration according to needs. Special conditions apply to patients previously addicted to opioids (clean) when they are to be operated on. Non-opioids are sufficiently effective for low level pain and opiates can be avoided. Opioid therapy with inclusion of a non-opioid is necessary following major operations or for severe postoperative pain, even as i.v. patient-controlled analgesia (i.v. PCA) if needed. For these patients a relapse to addiction can be provoked by insufficient administration of analgesics, not by pain management including opioids.     

Paracetamol im Kindesalter Aktueller Wissensstand und Hinweise für einen rationalen Einsatz zur postoperativen Analgesie

The administration of paracetamol (in the US known as acetaminophen) to children and infants for postoperative pain after minor surgery is a well established and safe treatment option, if appropriately used. However, if paracetamol is dosed according to traditional recommendations (about 20 mg/kg body weight) frequently a sufficient analgetic effect cannot be achieved immediately after painful interventions. Recently, a higher initial dose (40 mg/kg body weight) was suggested for effective postoperative pain control, which seems especially important for children after ambulatory anesthesia, but may also be associated with certain risks to the patient. Current recommendations also involve appropriate timing and route of administration of paracetamol to be most effective under different clinical circumstances. In contrast, the risk for liver toxicity appears to be very low, if the daily paracetamol dose does not exceed 90 mg/kg body weight in otherwise healthy children, and if specific risk factors of the individual patient are always considered. This review discusses the recent publications on pharmacokinetics and -dynamics, the clinical use and dosing, as well as the risks and benefits of paracetamol for the treatment of postoperative pain in children and infants. Based on this information, specific dosing regimes for the postoperative period are suggested for neonates and infants, as well as for children in different age groups.     

Intravenous clonidine infusion in infants after cardiovascular surgery

BACKGROUND: The aim of this study was to investigate the hemodynamic profile and heart rhythm in infants who were given intravenous clonidine infusion after prolonged analgesia/sedation following cardiac surgery. METHODS: This is a single center retrospective review. A total of 542 cardiovascular surgical procedures in infants aged 0-24 months with congenital heart disease were performed between 01/2003 and 12/2005 at the Deutsches Herzzentrum in Berlin. The majority received no long-term analgesia/sedation, but 50 (9%) of these infants received clonidine (dosed at 0.18-3.6 microg.kg(-1).h(-1)) for sedation and to reduce withdrawal symptoms such as CNS hyperactivation, hypertension, tachycardia, and fever. The hospital records of these infants were studied. RESULTS: Fifty infants (median age 5.0 months, median body weight 5.3 kg, 32 males/18 females) received prolonged analgesia/sedation to ensure hemodynamic stability. Clonidine infusion started on day 5 (median) after surgery. During clonidine treatment we found an age-related normalized profile of hemodynamic parameters with a reduction of heart rate and mean arterial pressure from the upper norm to the mean within 24 h (P < 0.001). In no case did clonidine cause low blood pressure resulting in additional therapy to reach the target blood pressure. There were no adverse effects on cardiac rhythm, especially no onset of atrioventricular block. Midazolam, fentanyl, and other opioids could be ended on day 4 of clonidine treatment. CONCLUSIONS: Although off-label, it is feasible to use clonidine infusions in infants in the PICU setting after cardiac surgery without hemodynamic problems arising.     

Pain management after major orthopaedic surgery: current strategies and new concepts

Several recently developed analgesic techniques effectively control pain after major orthopaedic surgery. Neuraxial analgesia provided by epidural and spinal administration of local anesthetics and opioids provides the highest level of pain control; however, such therapy is highly invasive and labor intensive. Neuraxial analgesia is contraindicated in patients receiving low-molecular-weight heparin. Continuous plexus and peripheral neural blockades offer excellent analgesia without the side effects associated with neuraxial and parenteral opioids. Intravenous patient-controlled analgesia allows patients to titrate analgesics in amounts proportional to perceived pain stimulus and provide improved analgesic uniformity. Oral sustained-release opioids offer superior pain control and greater convenience than short-duration agents provide. Opioid dose requirements may be reduced by coadministration of COX-2-type nonsteroidal analgesics.     

Preemptive analgesia in foot and ankle surgery

Central neuroplasticity, or changes in CNS processing due to surgical nociception. can amplify postoperative pain. As a result, a hyperalgesic state called wind-up can occur, having debilitating effects on postoperative patients. Preemptive analgesia works to prevent this process and results in a more positive surgical experience. Inhibition of afferent pain pathways by use of local anesthetic blocks, altered perception of pain with opioid use, and inhibition of pain pathways by NMDA receptor antagonists are examples of preemptive analgesia. Using a combination of preemptive modalities and addressing patients' perceptions can aid in interrupting pathologic pain cycles. Positive and modest results have been obtained from animal and human preemptive trials, yet basic pathophysiology demonstrates the validity and importance of preemptive analgesia. Future studies are needed to test effective blockade of afferent input while controlling perception, hyperalgesia, and NMDA receptor activity. The Agency for Health Care Policy and Research now recommends a multifaceted approach to postoperative pain. The goal in pain management is to inhibit destructive pain pathways, maintain intraoperative analgesia, and prevent central sensitization. Preliminary results of multimodal preemptive analgesia trials continue to be promising.     

全身麻醉药在脊髓内的作用机制

脊髓是全身麻醉药抑制伤害性刺激体动反应和抗伤害效应的重要作用部位,含有不同配体门控离子受体等多个可能介导麻醉效应的靶点.不同药物在脊髓内经各自特异靶点通过多种分子机制发挥作用.现就全身麻醉药制动和镇痛效应在脊髓内的作用位点和分子机制作一综述.     

Airway structure, function and development in health and disease

Until they are fully mature, the airways are highly susceptible to damage. Factors that may contribute to vulnerability of immature airways and the occurrence of bronchopulmonary dysplasia (BPD) in preterm neonates include decreased contractility of smooth muscles of the airway, which leads to generation of lower forces, and immaturity of airway cartilage, leading to increased compressibility of developing airways. Mechanical ventilation has little effect on adult airways, but affects the dimensions and mechanical properties of preterm and newborn airways. Techniques for clinical evaluation of airway function include: (i). measurements of airway function during tidal breathing (airway resistance and reactivity are significantly elevated in infants with BPD); (ii). forced expiratory flow measurements [small-airway obstruction in infants with BPD is indicated by markedly reduced maximal volume measurements (Vmax)]; (iii). radiography procedures (plain radiographs, fluoroscopy, computed tomography and virtual bronchoscopy); and (iv). endoscopy procedures (rigid or flexible bronchoscopy, with or without measurement of oesophageal pressure). Imaging has demonstrated an excessively decreased airway cross-sectional area during exhalation in infants with BPD and acquired tracheomegaly in very preterm infants who had received mechanical ventilatory support. To further advance our understanding of how the airways develop, and to design less damaging protocols for mechanical ventilation in preterm neonates, basic laboratory studies of airway ultrastructure need to be performed and the results correlated with clinical pulmonary function studies.     

Pain, opioid tolerance and sensitisation to nociception in the neonate

Pain is commonplace in newborn infants. Opioid analgesics have become increasingly used to reduce different types of pain in neonates, including pain from surgery, medical procedures and chronic conditions. Adverse effects of opioids include respiratory depression, hypotension and tolerance. These adverse effects can be minimised by utilising specific administration techniques and constant monitoring. Recent studies have demonstrated that untreated pain can have long-term effects on infant pain behaviours months beyond the events, thus, opioid analgesics may have a beneficial role that extends beyond the immediate painful event(s).