Halothane-morphine compared with high-dose sufentanil for anesthesia and postoperative analgesia in neonatal cardiac surgery

Effects of intravenous immunoglobulin on muscle weakness and calcium-channel autoantibodies in the Lambert-Eaton myasthenic syndrome

Intravenous immunoglobulin improves many antibody-mediated autoimmune disorders, but its mode of action is unknown. We investigated its effects on muscle strength and on the serum titer of the calcium-channel autoantibodies that are likely to be pathogenic in the Lambert-Eaton myasthenic syndrome (LEMS). In a randomized, double-blind, placebo-controlled crossover trial, serial indices of limb, respiratory, and bulbar muscle strength and the serum titer of calcium-channel antibodies in nine patients were compared over an 8-week period, using the area-under-the-curve approach, following infusion on two consecutive days of immunoglobulin at 1 g/kg body weight/day (total dose 2.0 g/kg body weight) or placebo (equivalent volume of 0.3% albumin). Calcium-channel antibodies were measured by radioimmunoassay using 125I-omega-conotoxin MVIIC. Direct anti-idiotypic actions of immunoglobulin were tested in this assay. Immunoglobulin infusion was followed by significant improvements in the three strength measures (p = 0.017 to 0.038) associated with a significant decline in serum calcium-channel antibody titers (p = 0.028). Improvement peaked at 2 to 4 weeks and was declining by 8 weeks. Mean serum titers were unchanged at 1 week, however, and direct anti-idiotypic neutralization by immunoglobulin was not demonstrable in vitro. We conclude that immunoglobulin causes a short-term improvement in muscle strength in LEMS that probably results from the induced reduction in calcium-channel autoantibodies. The reduction is not due to a direct neutralizing action of the immunoglobulin, but a delayed anti-idiotypic action cannot be excluded. Improvement following intravenous immunoglobulin in other autoantibody-mediated disorders may similarly be associated with decline in levels of pathogenic autoantibodies.

Complications of intravenous immune globulin treatment in neurologic disease

Intravenous immune globulin (IVIg) is advocated as a safe treatment for immune-mediated neurologic disease. We reviewed the medical records of 88 patients who were given IVIg for a neurologic illness. Major complications in four patients (4.5%) included congestive heart failure in a patient with polymyositis, hypotension after a recent myocardial infarction, deep venous thrombosis in a bed-bound patient, and acute renal failure with diabetic nephropathy. Other adverse effects included vasomotor symptoms 26, headache 23, rash 5, leukopenia 4, fever 3, neutropenia 1, proteinuria (1.9 g/day) 1, viral syndrome 1, dyspnea 1, and pruritus 1. Fifty-two patients (59%) had some adverse effect of IVIg infusion, most commonly vasomotor symptoms, headaches, fever, or shortness of breath in 40 (45%), which improved with reduced infusion rate or symptomatic medications. Five (6%) had asymptomatic laboratory abnormalities and seven (8%) had other minor adverse effects. Adverse effects led to discontinuation of therapy in 16% and permanent termination of therapy in 10% of patients. There was no mortality or long-term morbidity. Although adverse effects were frequent, serious complications were rare except in patients with heart disease, renal insufficiency, and bed-bound state.

Large-dose intrathecal morphine for coronary artery bypass grafting

Aggressive control of pain during the immediate postoperative period after cardiac surgery, associated with decreased blood catecholamine levels, may decrease morbidity and mortality. This study investigated the use of large-dose intrathecal morphine for cardiac surgery and its effect on postoperative analgesic requirements and blood catecholamine levels. Patients were randomized to receive either 4.0 mg of intrathecal morphine (Group MS) or intrathecal saline placebo (Group NS). Perioperative care was standardized and included postoperative patient-controlled analgesia. Arterial blood samples were obtained perioperatively to ascertain catecholamine levels. Patients in Group MS required significantly less postoperative intravenous morphine than patients in Group NS. Although perioperative norepinephrine and epinephrine levels in Group MS patients tended to be lower than Group NS patients, the differences were not statistically significant. In conclusion, large-dose intrathecal morphine initiates reliable postoperative analgesia but does not reliably attenuate the stress response during and after cardiac surgery.

An investigation of the effects of heparin, low molecular weight heparin, protamine, and fentanyl on the balance of pro- and anti-inflammatory cytokines in in-vitro monocyte cultures

We report a study conducted to determine if drugs given peri-operatively during cardiac surgery could themselves modulate the balance of pro- and anti-inflammatory cytokines. We determined the cytokine response of 10 separate in vitro monocyte cultures to the administration of drugs at concentrations used during cardiac 'surgery:fentanyl (25 ng.ml-1), heparin 2.5 i.u.ml-1, heparin with an equal concentration of protamine, and enoxaparin 2.5 i.u.ml-1. Fentanyl, heparin and low molecular weight heparin (enoxaparin) led to increased tumour necrosis factor alpha but this did not reach statistical significance. Tumour necrosis factor soluble receptor 1 and 2 was not elevated. Interleukin-1 beta was increased by heparin (p < 0.05), whereas interleukin-1 receptor antagonist was increased by fentanyl (p < 0.05). Protamine blocked the heparin-induced increase in tumour necrosis factor alpha and interleukin-1 beta. These data raise the possibility that endogenous and exogenously administered opioids may be partly contributing to the interleukin-1 receptor antagonist response seen during major surgery.

Oral sweet solution reduces pain-related behaviour in preterm infants

To evaluate the effectiveness of oral sucrose in the prevention of pain-induced crying in preterm infants, a sample of 28 healthy neonates (15M, 13F; gestational age at procedure less than 37 weeks) who were having routine blood drawn by arm venipuncture was studied. Infants were randomly allocated to receive by mouth, using a syringe, 2 ml of one of three solutions: spring water (group W) and sucrose 12 and 24% w/v (groups S12 and S24, respectively), all in water vehicle. After 2 min, while awake, arm venipuncture was performed and duration of crying was measured. The time spent crying was reduced in the group treated with the sweetest solution (S24, n = 8, mean = 19.1 s). No difference was observed between the S12 group (n = 8, mean = 63.1 s) and W group (n = 12, mean = 72.9 s). Physiological measurements were recorded at different time points to evaluate excessive basal and procedural distress.

Plasma exchange combined with azathioprine in multiple sclerosis using serial gadolinium-enhanced MRI to monitor disease activity: a randomized single-masked cross-over pilot study

We enrolled 11 patients with secondary progressive MS in a randomized single-masked cross-over study of plasma exchange (PE) in combination with azathioprine 2 mg/kg. PE was performed once a week for 4 weeks and thereafter every second week for 20 weeks (14 treatments). Eight patients completed the whole trial, and three patients discontinued the trial, two during the run-in period of azathioprine treatment and one at the introduction of PE. The primary efficacy variables were the number of gadolinium-enhancing lesions and the occurrence of new enhancing lesions on serial MRI performed every 3 weeks during the PE and the control period. Secondary efficacy variables were the total MS lesion load on T2-weighted MRI, multimodal evoked potentials, and clinical neurologic ratings. No significant differences were found regarding the number of enhancing lesions or occurrence of new enhancing lesions in the two periods. Although the total MS lesion load on MRI was significantly lower (p < 0.02) and central motor conduction times decreased significantly (p < 0.05) during PE, this small study did not provide sufficient evidence for a significant beneficial effect of PE or encourage a subsequent large randomized parallel group study.

Evidence for morphine downregulating immunocytes during cardiopulmonary bypass in a porcine model

Cardiopulmonary bypass is associated with both cellular immunosuppression and an inflammatory response. Previous studies have demonstrated that morphine, a naturally occurring substance, can downregulate granulocyte, monocyte and endothelial activity. It can even prevent the activation caused by exposing these cells to plasma obtained from patients undergoing cardiopulmonary bypass. The present study demonstrates that preadministering a high dose of morphine (3.3 mg/kg) to pigs prior to cardiopulmonary bypass also diminishes the activation levels of these cells. In animals not given morphine, monocyte activation levels were 45% compared to 14% exposed to the opiate. Granulocytes also exhibited the same statistically significant (P < 0.05) drop in cellular activation. Activation is determined by computer-assisted microscopic image analysis whereby cellular shape is indicative of the cells activity. Additionally, in animals pretreated with morphine, a twofold increase in the number of cells was obtained, indicating that the endothelium also was downregulated.

Pathophysiology, Diagnosis, and Management of Pulmonary Hypertension in Infants and Children

Pulmonary hypertension (PH) may occur as a primary process or as a complication of several diseases. In the pediatric population, PH secondary to congenital heart disease, chronic hypoxemia, or acute respiratory failure is more common than primary PH. Regardless of etiology, PH may lead to significant morbidity or mortality as a consequence of right-to-left shunting across cardiovascular channels or right heart failure. In this review, PH is defined in terms of the determinants of pulmonary blood flow: pulmonary artery pressure, downstream pressure, and pulmonary vascular resistance. Research addressing both normal developmental changes in pulmonary vascular resistance and abnormal pulmonary vascular reactivity is then reviewed, followed by a discussion of the etiologies of PH in children. Some of the more common clinical presentations of PH are presented focussing on the differences seen between patients with and without intracardiac communications. Assessment of the severity of PH using both noninvasive (electrocardiogram, echocardiogram, magnetic resonance imaging) and invasive (cardiac catheterization, lung biopsy) techniques is then discussed. Treatment of PH is presented, focussing on restoration of adequate pulmonary blood flow through use of both conventional and newer vasodilator therapies. The review concludes by noting the limits to our understanding of the pathogenesis and therapy of PH.

Effects of fentanyl administration on general and cerebral haemodynamics in sick newborn infants

Despite the wide use of fentanyl for analgesia in newborns, concerns have been raised about potential haemodynamic side-effects. Since sick newborns may lose their cerebral blood flow autoregulation, a drug-induced haemodynamic instability could lead to brain injury. We assessed the effects of a 15-min infusion of fentanyl (3 micrograms/kg) on the general and cerebral haemodynamics in 15 newborns (median gestational age 29 weeks, 25th-75th percentile, range 28-31 weeks; birthweight 1170 g, range 955-1790 g). The heart rate and mean arterial blood pressure were continuously recorded. Mean cerebral blood flow velocity and pulsatility index were measured using pulsed Doppler ultrasound before, during and up to 60 min after the onset fentanyl administration. No significant modification of general or cerebral haemodynamics was observed. In conclusion, the infusion of 3 micrograms/kg of fentanyl did not lead to any deleterious effect on the general or cerebral haemodynamics in sick normovolaemic newborns.

Premature Infant Pain Profile: development and initial validation

OBJECTIVE

Inadequate assessment of pain in premature infants is a persistent clinical problem. The objective of this research was to develop and validate a measure for assessing pain in premature infants that could be used by both clinicians and researchers.

DESIGN

The Premature Infant Pain Profile (PIPP) was developed and validated using a prospective and retrospective design. Indicators of pain were identified from clinical experts and the literature. Indicators were retrospectively tested using four existing data sets.

PATIENTS AND SETTINGS

Infants of varying gestational ages undergoing different painful procedures from three different settings were utilized to develop and validate the measure.

METHODS AND RESULTS

The largest data set (n = 124) was used to develop the PIPP. The development process included determining the factor structure of the data, developing indicators and indicator scales and establishing internal consistency. The remaining three data sets were utilized to establish beginning construct validity.

CONCLUSIONS

The PIPP is a newly developed pain assessment measure for premature infants with beginning content and construct validity. The practicality and feasibility for using the PIPP in clinical practice will be determined in prospective research in the clinical setting.

Depression of cardiac function after deep hypothermic circulatory arrest in deeply anesthetized neonatal lambs

Cardiac dysfunction is common after neonatal cardiac operations. Previous in vivo studies in neonatal animal models however, have failed to demonstrate decreased left ventricular function after ischemia and reperfusion. Cardiac dysfunction may have been masked in these studies by increased endogenous catecholamine levels associated with the use of light halothane anesthesia. Currently, neonatal cardiac operations are often performed with deep opiate anesthesia, which suppresses catecholamine surges and may affect functional recovery. We therefore examined the recovery of left ventricular function after ischemia and reperfusion in neonatal lambs anesthetized with high-dose fentanyl citrate (450 micrograms/kg administered intravenously). Seven intact neonatal lambs with open-chest preparation were instrumented with left atrial and left ventricular pressure transducers, left ventricular dimension crystals, and a flow transducer. The lambs were cooled (< 18 degrees C) on cardiopulmonary bypass (22 +/- 6 minutes), exposed to deep hypothermic circulatory arrest (46 +/- 1 minutes), and rewarmed on cardiopulmonary bypass (30 +/- 10 minutes). Catecholamine levels and indexes of left ventricular function were determined before (baseline) and 30, 60, 120, 180, and 240 minutes after termination of cardiopulmonary bypass. Levels of epinephrine, norepinephrine, and dopamine were unchanged from baseline values. Left ventricular contractility (slope of end-systolic pressure-volume relationship) was depressed from baseline value (31.7 +/- 9.3 mm Hg/ml) at 30 minutes (15.7 +/- 6.4 mm Hg/ml) and 240 minutes (22.7 +/- 6.4 mm Hg/ml) but unchanged between 60 and 180 minutes. Left ventricular relaxation (time constant of isovolumic relaxation) was prolonged from baseline value (19.0 +/- 3.0 msec) at 30 minutes (31.4 +/- 10.0 msec) and 240 minutes (22.1 +/- 2.8 msec) but unchanged between 60 and 180 minutes. Afterload (left ventricular end-systolic meridional wall stress) was decreased at 30, 60, and 240 minutes. Indexes of global cardiac function (cardiac output, stroke volume), preload (end-diastolic volume), and left ventricular compliance (elastic constant of end-diastolic pressure-volume relationship) were unchanged from baseline values. In deeply anesthetized neonatal lambs exposed to ischemia and reperfusion, left ventricular contractility, relaxation, and afterload are markedly but transiently depressed early after reperfusion and mildly depressed late after reperfusion.

Lumbar epidural morphine infusions for children undergoing cardiac surgery

OBJECTIVE

To determine whether outcomes and costs in children undergoing cardiac surgery are affected by the method of postoperative pain management.

DESIGN

Retrospective, case control.

SETTING

Tertiary care children's hospital in a university setting.

PARTICIPANTS

Two groups of children undergoing cardiac surgery for palliation or repair of congenital heart disease oer a 21-month period between January 1993 and September 1994.

INTERVENTIONS

Lumbar epidural morphine infusions (LEM) in one group, and IV opioid (IVO) medication in the other for postoperative pain control.

MEASUREMENTS AND MAIN RESULTS

Hospital courses of 27 LEM patients and 27 IVO patients were analyzed. In LEM patients, epidural catheters were placed following anesthetic induction, but before anticoagulation. A bolus of 50 micrograms/kg of preservative-free morphine sulfate was administered through the catheter, followed by a continuous infusion at 3 to 4 micrograms/kg/h for 22 to 102 (median, 46) hours postoperatively. The IVO patients received 50 micrograms/kg, IV, of fentanyl before incision followed by a continuous infusion at 0.3 microgram/kg/min. The fentanyl infusion rate was decreased to 0.1 microgram/kg/min postoperatively and maintained for 24 hours. Although the LEM group was demographically similar to the IVO group, times to tracheal extubation, transfer from the intensive care unit, and resumption of regular diet were significantly shorter in LEM patients. LEM and IVO patients received similar amounts of fentanyl during surgery (10.4 +/- 19.3 micrograms/kg/h v 13.7 +/- 8.1 micrograms/kg/h, p = 0.4). However, during postoperative recovery, LEM patients who were extubated late received significantly less supplemental opioid medication than IVO patients extubated late during the first 5 postoperative days. No complications related to dural puncture, bleeding into the epidural space, or respiratory depression were encountered. Pruritus and nausea/vomiting were the most commonly reported morbidities in both groups. Fifty-six percent (15/27) of LEM patients and 41% of IVO patients reported pruritus (p = 0.4). There was no significant difference in the incidence of nausea and vomiting between the groups (34% v 30%, respectively).

CONCLUSIONS

Given the present methodologic limitations, the authors found improved outcomes only in LEM patients extubated late compared with IVO patients. Randomized, prospective studies to evaluate this conclusion and to determine the comparative efficacy and safety of LEM infusions are in progress.

Liver function disturbances in Guillain-Barré syndrome: a prospective longitudinal study in 100 patients. Dutch Guillain-Barré Study Group

In 100 consecutive patients with Guillain-Barré syndrome, we assessed liver function on admission and at fixed intervals after either intravenous immunoglobulin (IgIV) or plasma-exchange (PE) treatment. On admission, 38% showed a plasma alanine aminotransferase elevation, gamma glutamyl transferase elevation, or both or more than 1.5 times the upper limit of normal. Ten of these patients had serologic evidence of recent cytomegalovirus infection. The remaining 28 patients were negative for other known causes of liver damage, including infection with Epstein-Barr virus or hepatitis A, B, and C; alcohol abuse; hepatotoxic drugs; recent surgery; and concurrent liver disease. In a hospital control group of 100 consecutive patients with subarachnoid hemorrhage, only 5 had unexplained liver function disturbances on admission (p < 0.0001). In the IgIV-treated group, the percentage of patients with elevated liver function tests increased from 35% before to 69% shortly after treatment at 2 weeks postadmission (p < 0.005). In the PE-treated group, this percentage decreased somewhat from 41% to 36% (not significant). There was also a significant rise in median plasma activity of the various liver enzymes in the IgIV group. At 1 month, however, significant difference had disappeared. At 3 and 6 months, the percentage of patients with liver function disturbances reached a significantly lower level in both treatment groups compared with the time of admission. We concluded that many patients with Guillain-Barré syndrome had mild liver function disturbances without obvious cause. In addition, IgIV treatment was associated with mild transient liver function disturbances through an unknown mechanism.

Continuous caudal anaesthesia with chloroprocaine as an adjunct to general anaesthesia in neonates

PURPOSE

The authors prospectively evaluated the use of a continuous caudal epidural infusion of chloroprocaine as an adjunct to general anaesthesia during intra-abdominal surgery in neonates.

CLINICAL FEATURES

The technique was used in 25 neonates ranging in age from 1 to 28 days and in weight from 2.2 to 4.9 kg. Following anaesthetic induction and tracheal intubation, an initial bolus dose of chloroprocaine 3% (1 or 1.5 ml.kg-1) was followed by a continuous infusion of 1 or 1.5 ml.kg-1.hr-1 administered through a caudal epidural catheter. No parenteral opioids were administered. The duration of the surgical procedures varied from one hour five minutes to three hours 15 min. The first three neonates received a bolus dose of 1.0 ml.kg-1 followed by an infusion of 1.0 ml.kg-1.hr-1 chloroprocaine 3%. These three neonates required an additional bolus dose followed by an increase in the infusion to 1.5 ml.kg-1.hr-1 to provide surgical anaesthesia. Adequate intraoperative anaesthesia was achieved in all 25 neonates with an infusion of 1.5 ml.kg-1.hr-1 of chloroprocaine 3%. This was evidenced by a lack of haemodynamic response to surgical manipulation. No neonate required more than 0.2% isoflurane or 70% nitrous oxide in oxygen. No episodes of haemodynamic instability (decreased blood pressure/bradycardia) related to the caudal epidural anaesthesia were noted. Twenty-three of 25 of the neonates' tracheas were extubated immediately (within 10 minutes) following the surgical procedure.

CONCLUSIONS

Caudal anaesthesia with a continuous infusion of chloroprocaine can be used as an adjunct to general anaesthesia during abdominal surgery in neonates. Our initial experience suggests that the combined technique may eliminate the need for parenteral opioids and limit the intraoperative requirements for inhalational anaesthetic agents.

Pilot trial of immunoglobulin versus plasma exchange in patients with Guillain-Barré syndrome

We compared intravenous immunoglobulin (IVIG) and plasma exchange (PLEX) in the treatment of 50 patients with Guillain-Barré syndrome (GBS). Standard outcome measures did not differ for the two groups. Sixty-one percent of the PLEX-treated group and 69% of the IVIG-treated group improved by one disability grade at 1 month. The complication rate was higher in the PLEX-treated group. We conclude that the efficacy of IVIG in the treatment of GBS is comparable with that of PLEX and that it can be used safely, although we had a small number of patients. We did not observe a higher relapse rate with IVIG. The usefulness of combination therapy is unknown at this time.

Catecholamine and cortisol responses to lower extremity revascularization: correlation with outcome variables. Perioperative Ischemia Randomized Anesthesia Trial Study Group

OBJECTIVE

To determine whether catecholamine and cortisol secretory responses to surgery contribute to postoperative complications.

DESIGN

Prospective, randomized, case series.

SETTING

A university hospital operating suite and surgical intensive care unit.

PATIENTS

Sixty patients undergoing lower extremity vascular surgery.

INTERVENTIONS

Patients were randomized to receive either epidural anesthesia/epidural opiate analgesia (regional anesthesia) or general anesthesia/intravenous patient-controlled analgesia (general anesthesia).

MEASUREMENTS AND MAIN RESULTS

Anesthesia was managed according to a prospectively designed protocol. Hemodynamic parameters and plasma catecholamine concentrations were determined at specific intraoperative and postoperative time points. Intraoperative and postoperative urine samples were collected and analyzed for free cortisol concentrations. Outcomes evaluated were cardiac (nonfatal myocardial infarction and cardiac death) and surgical (graft occlusion). Mean arterial pressure during emergence from anesthesia and in the early postoperative period correlated positively with plasma norepinephrine concentration (p < .01). In addition, plasma catecholamine concentrations were higher in patients with postoperative hypertension. Plasma norepinephrine concentrations at the time of emergence from anesthesia and postoperatively were also higher in patients requiring repeat surgery for graft revision, thrombectomy, or amputation (p < .05). Multivariate analysis indicated that the norepinephrine concentration at the time of emergence, but not type of anesthesia, correlated with reoperation for graft occlusion, suggesting that the previously reported beneficial effect of regional anesthesia may be due to modulation of the stress response. Myocardial infarction or cardiac death occurred in three patients. These patients had markedly increased catecholamine concentrations.

CONCLUSIONS

The catecholamine response to lower extremity vascular surgery contributes to the development of postoperative hypertension and may also be important in the development of thrombotic complications.

Direct cardiac electrophysiologic effects of sufentanil and vecuronium in isolated guinea-pig hearts

Sufentanil and vecuronium are commonly used simultaneously in anaesthesia. Bradycardia and asystole have been described immediately after the administration of these two compounds. Therefore, the purpose of the present study was to evaluate the direct cardiac effects of sufentanil and vecuronium in all parts of the cardiac pacemaker and conduction system. The electrophysiological effects of sufentanil and vecuronium were studied in isolated spontaneously beating guinea-pig hearts perfused by the method of Langendorff. At a concentration of 0.1 mumol/l sufentanil a significant reduction of the spontaneous sinus rate, prolongation of atrioventricular, intraventricular and His' bundle conduction could be observed. The highest concentration of 10 mumol/l of sufentanil led to an overall slowing of conduction velocity and to an profound showing of spontaneous sinus rate. AV nodal as well as atrial and ventricular refractoriness were markedly prolonged at this high concentration of sufentanil. In contrast, during perfusion with vecuronium at a concentration of 0.1 mumol/l up to 10 mumol/l no significant effects on cardiac conduction and pacemaker activity could be observed. In conclusion, the electrophysiological effects of sufentanil are comparable to that of unspecific calcium antagonists. Therefore, especially in patients with a preexisting damage of the cardiac conduction system, the indirect effect of the combination of sufentanil and vecuronium which is predominantly responsible for bradycardia and asystole may be worsened by the direct effects of sufentanil.

Sedation and Analgesia for Children in the Pediatric Intensive Care Unit

Several situations arise in the Pediatric Intensive Care Unit (PICU) patient which may require the pharmacologic control of pain and anxiety. The author discusses the various pharmacologic agents available for sedation and analgesia including the inhalational anesthetic agents, nitrous oxide, benzodiasepines, opioids, ketamine, propofol, and the barbiturates. While intravenous administration is generally chosen for the PICU patient, certain situations may arise which preclude this route. The available information concerning alternative routes of delivery for the various agents including subcutaneous and transmucosal administration is presented. The role of various regional anesthetic techniques to control pain in the PICU patient are reviewed.

Special needs of preterm infants in the management of pain and discomfort

Most infants born preterm are admitted to hospital neonatal intensive care units, where they undergo repeated multiple diagnostic and therapeutic procedures that result in pain and discomfort. Although there is convincing evidence to support the preterm infant's neurologic capacity for pain, management of pain often is not optimal. Accurate and reliable assessment of the preterm infant's pain is an important prerequisite for effective pain management. Pain assessment is a challenge for health professionals because the preterm infant's responses are less vigorous, more variable, and less consistent than are the responses of term neonates and older infants. Few reliable and valid assessment measures exist for this age group. There also is uncertainty in implementing pain-relieving intervention because of inadequate information on their safety and effectiveness and preconceived attitudes and beliefs of health professionals. The special needs of preterm infants related to the assessment and management of pain are discussed.

[Pain in hospitalized children]

Pain is present in many hospitalized children and this requires from every physician a constant attention to its recognition, evaluation and treatment. The semeiology of pain differs whether it is acute or chronic. Acute pain can be recognized from its various behavioural, motor and neurovegetative manifestations. Pain evaluation must be adapted according to age: autoevaluation procedures for children older than 5 years, behavioural scales for children younger than 5 years. One must know that there is an appropriate and efficient treatment for each stage of pain intensity. For a better recognition and management of pain in hospitalized children, the organization of teams specialized in the evaluation and treatment of pain in children is to be encouraged.

Hemodynamic characteristics of neonates following first stage palliation for hypoplastic left heart syndrome

BACKGROUND

It is widely held that the postoperative course of patients with hypoplastic left heart syndrome (HLHS) after stage 1 palliation is characterized by hemodynamic instability, which in part may be due to excessive pulmonary blood flow. Hence, avoidance of alkalosis and the use of minimally oxygen-enriched inspiratory gas are thought by many to be important, although there is little pertinent published data. This study was undertaken to characterize the postoperative course and to determine whether the FIO2 and blood pH are related to indices of hemodynamic stability in these infants.

METHODS AND RESULTS

The postoperative course of 25 consecutive infants undergoing first stage palliation for HLHS were retrospectively reviewed and the following data were obtained: arterial pressure, arterial blood gas measurements, the inotropic agents used, and multiple respiratory parameters. There was one operative death, and 2 patients died within 2 days, but 22 were extubated (mean, 5.2 +/- 4.1 days after surgery). Hospital mortality was 24%. Mean pH was > or = 7.51 for the first 9 hours after surgery and was > or = 7.45 for the entire period. The mean FIO2 was > or = 50% for the first 18 hours. The PaO2 was appropriate (37 +/- 6 mm Hg at 1 hour after surgery, increasing to 45 +/- 5 mm Hg by hour 73). Only modest inotropic support was needed to maintain appropriate blood pressure.

CONCLUSIONS

These data suggest that neither alkalosis nor relatively high inspired oxygen necessarily cause hemodynamic instability in these patients. To what extent these results are generalizable is unclear, but they suggest that there is nothing inherent with HLHS that mandates postoperative hemodynamic instability or unacceptable mortality.

Issues of assessment of pain and discomfort in neonates

Pain assessment in neonates often presents problems. The problem of inadequate or inaccurate assessment is complicated by issues related to the nature, consistency, and variability of the infant's physiologic and behavioral responses; the reliability, validity, specificity, sensitivity, and practicality of existing neonatal pain measures or measurement approaches; ethical questions about pain research in infants; and uncertainty about the responsibilities of health care professionals in managing pain in clinical settings. Despite these many issues, neonates need to be comfortable and as free of pain as possible to grow and develop normally. Valid and reliable assessment of pain is the major prerequisite for attaining this goal. Issues embodied in neonatal pain responses, measurement, ethical, and clinical considerations are explored. Suggestions for resolving some of these problems are presented.

Effect of propofol infusion on the endocrine response to cardiac surgery

The effect of propofol infusion on the stress response was studied in patients undergoing coronary artery bypass graft (CABG). Ten patients received propofol infusion during cardiopulmonary bypass (CPB) and ten controls received diazepam. Blood levels of cortisol, adrenaline and noradrenaline were sampled. There was a significant reduction in all three hormones (P < 0.05) in the study group. In addition, the amount of sodium nitroprusside used during CPB was significantly reduced (P < 0.05).

Effects of morphine, pentobarbital and amphetamine on formalin-induced behaviours in infant rats: sedation versus specific suppression of pain

The behavioural response of infant rats to intraplantar injection of formalin consists of specific directed behaviours (limb flexion, shaking and licking the injected paw) and non-specific behaviours that are also induced by non-nociceptive stimulation (squirming, hind limb kicks and whole body jerks), with specific indicators becoming more frequent as pups mature. The present study examined the effects of systemic morphine, pentobarbital and D-amphetamine on formalin-induced behaviours and behavioural state in rat pups from 1 to 20 days of age. Morphine (1 mg/kg) almost completely suppressed both specific and non-specific indicators of pain, and produced mild sedation relative to handled control pups. Pentobarbital (10 mg/kg) produced a similar degree of sedation and suppression of non-specific measures as morphine, but only had weak effects on specific measures in pups less than 1 week old, and no effects thereafter. Suppression of both specific and non-specific pain measures after amphetamine (2 mg/kg) emerged during the 2nd week of life and was not associated with sedation. Thus, morphine produced behavioural analgesia in infant rats in a model of injury-induced inflammatory pain from the 1st postnatal day, when their neurological maturity is similar to a 25-week human fetus, and 1 week before antinociception is observed in thermal and pressure tests. The effects of morphine were qualitatively different from a sedative dose of pentobarbital. The data support the contention that opioids have specific analgesic effects in premature human neonates and underline the need for pain measures that discriminate between sedation and analgesia.

A revised measure of acute pain in infants

Acute pain in infants is not assessed or managed optimally. The objectives of the study were (a) to adapt a behavioral pain assessment measure (Children's Hospital of Eastern Ontario Pain Scale, CHEOPS) for use with infants, and (b) to establish the reliability and validity of the measure in a study of infants undergoing immunization. Ninety-six healthy 4- to 6-month-old infants were randomized to receive either the local anesthetic cream Eutectic Mixture of Local Anesthetics (EMLA) (N = 49), or a placebo (N = 47) prior to immunization. The infant's behavioral response was videotaped immediately before and following the immunization. Postprocedural pain scores were assessed from the videotape and were significantly lower in infants who received EMLA (P = 0.01). Pain scores were also significantly correlated with visual analogue scale (VAS) scores assessed during vaccination. Five independent raters also independently rated ten infants to determine interrater reliability. Agreement between raters' scores was high (intraclass correlation coefficient, 0.95). Results from this study suggest that this measure has beginning construct and concurrent validity and interrater reliability when used in a research study. Further testing of the measure in the clinical setting is required.

Choice of anesthesia and intraoperative monitoring for lower extremity revascularization

The prevalence of significant coronary artery disease re-enforces the importance of careful preoperative and intraoperative management in patients undergoing lower extremity revascularization. This article presents a practical approach toward the evaluation of anesthetic risk and the proper use of anesthetic agents and monitoring devices to minimize morbidity. The role of general and regional anesthetic agents is discussed, and complications of both techniques are presented.

The Norwood operation and subsequent Fontan operation in infants with complex congenital heart disease

From April 1987 to September 1993, 60 infants underwent a Norwood operation for complex congenital heart disease including hypoplastic left heart syndrome (n = 41), ventricular septal defect and subaortic stenosis with aortic arch interruption/severe coarctation (n = 7), complex single right ventricle with subaortic stenosis (n = 8), critical aortic stenosis with endocardial fibroelastosis (n = 2), and malaligned primum atrial septal defect with coarctation (n = 2). Age at operation ranged from 1 day to 3.9 months (mean 9 days, median 3.5 days). The operative mortality (< 30 days) was 33% (20 patients). Late mortality was 17% (10 patients). Nine of the 20 (45%) operative deaths occurred during the first 2 days after the operation as a result of sudden hemodynamic instability. All four infants with premature closure of the foramen ovale had pulmonary lymphangiectasia and died of pulmonary failure. Seven operative deaths have occurred in 36 patients since 1990 (19%); in the past 2 years, no operative deaths have occurred in 22 patients. Overall, there are 30 long-term survivors (50%). Twenty-one of these 30 infants have undergone a two-stage repair with a modified Fontan operation at 7.3 to 27.6 months of age (mean 18.1 months) with no mortality. Six patients have entered a three-stage repair strategy by undergoing a hemi-Fontan procedure at 6.8 to 23.0 months (mean 8.8 months) with no mortality, and two of these patients have now had their modified Fontan operation at 23.0 to 46.7 months of age with no mortality (four are still awaiting surgery). Two patients have undergone a two-ventricle repair with a Rastelli procedure, with no mortality at 7.4 and 14.1 months of age. Early in our experience, infants undergoing the Norwood operation had a high early mortality most often related to sudden hemodynamic instability. After we instituted a protocol that adds carbon dioxide to the inspired gas during postoperative mechanical ventilation, the postoperative course became more stable and there have been no operative deaths. In summary, the operative mortality for the Norwood operation continues to improve. A subsequent Fontan operation can be performed with excellent clinical results.

General stress response to conventional and laparoscopic cholecystectomy

OBJECTIVE

In many retrospective and prospective observational studies, laparoscopic cholecystectomy (LC) compares favorably with conventional cholecystectomy (CC), with respect to length of hospital stay, postoperative pain, and pulmonary function, indicating a diminished operative trauma. Comparison of laboratory findings (stress hormones, blood glucose, interleukins) are a possibility to objectify stress and tissue trauma of laparoscopic and conventional cholecystectomy.

SUMMARY BACKGROUND DATA

Major body injury, surgical or accidental, evokes reproducible hormonal and immunologic responses. The magnitude of many of these changes essentially is proportional to the extent of the injury.

METHODS

In a prospective study, biochemical stress parameters were measured in the blood of patients undergoing elective cholecystectomy because of symptomatic cholecystolithiasis. Patients with acute cholecystitis, pancreatitis, choledocholithiasis, or malignant disease were excluded. Values from 40 patients after LC and from 18 patients after CC were compared. Both groups had similar patient characteristics, baseline values, and perioperative care, except for deeper anesthesia during CC.

RESULTS

On postoperative day 1, epinephrine (p = 0,05), norepinephrine (p = 0.02), and glucose (p = 0.02) responses were higher after CC. Two days postoperatively, norepinephrine remained higher after CC (p < 0.01). Interleukin-1 beta responses were higher during (p < 0.01) and 6 hours after CC (p = 0.03). Interleukin-6 responses were higher 6 hours (p = 0.03), 1 day (p = 0.02), and 2 days (p < 0.01) after CC.

CONCLUSIONS

The results show significant lower values of intraoperatively and postoperatively measured epinephrine, norepinephrine, interleukin-1 beta, and interleukin-6 in patients with laparoscopic cholecystectomy, indicating a minor stress response and tissue trauma in this group of patients. The results correspond to the favorable results of most other trials evaluating clinical aspects of laparoscopic cholecystectomy.

Hepatitis C infection, cryoglobulinemia, and vasculitic neuropathy. Treatment with interferon alfa: case report and literature review

A patient with mononeuropathy multiplex, hepatitis C viral infection, and mixed cryoglobulinemia had axonal degeneration by EMG and vasculitis of the epineurial vessels on sural nerve biopsy. There was no evidence of viral particles in the nerve by immunofluorescence. Treatment with interferon alfa improved the patient's symptoms and cleared the hepatitis C viral RNA and cryoglobulins from the serum.

Facilitated tucking: a nonpharmacologic comfort measure for pain in preterm neonates

OBJECTIVE

To identify the effectiveness of "facilitated tucking," a nonpharmacologic nursing intervention, as a comfort measure in modulating preterm neonates' physiologic and behavioral responses to minor pain.

DESIGN

Prospective, repeated measure, random sequencing, and experimental.

SETTING

Level III neonatal intensive-care unit of a tertiary care university pediatric hospital.

PARTICIPANTS

Thirty preterm neonates, 25-35 weeks gestation.

INTERVENTIONS

Heart rate, oxygen saturation, and sleep state were recorded 12 minutes before, during, and 15 minutes after two heelsticks, one with and one without facilitated tucking.

HYPOTHESIS

Premature neonates will have less variation in heart rate and hemoglobin oxygen saturation, shorter crying and sleep disruption times, and less fluctuation in sleep states in response to the painful stimulus of a heelstick with facilitated tucking than without.

RESULTS

Neonates demonstrated a lower mean heart rate 6-10 minutes post-stick (p < 0.04), shorter mean crying time (p < 0.001), shorter mean sleep disruption time (p < 0.001), and fewer sleep-state changes (p = 0.003) after heelstick with facilitated tucking than without.

CONCLUSION

Facilitated tucking is an effective comfort measure in attenuating premature neonates' psychologic and behavioral responses to minor pain.

Factors influencing early and late outcome of the arterial switch operation for transposition of the great arteries

Between January 1983 and January 1992, 470 patients underwent an arterial switch operation at our institution. An intact (or virtually intact) ventricular septum was present in 278 of 470 (59%); a ventricular septal defect was closed in the remaining 192. Survivals at 1 month and 1, 5, and 8 years among the 470 patients were 93%, 92%, 91%, and 91%, respectively. The hazard function for death (at any time) had a rapidly declining single phase that approached zero by one year after the operation. Risk factors for death included coronary artery patterns with a retropulmonary course of the left coronary artery (two types) and a pattern in which the right coronary artery and left anterior descending arose from the anterior sinus with a posterior course of the circumflex coronary. The only procedural risk factor identified was augmentation of the aortic arch; longer duration of circulatory arrest was also a risk factor for death. Earlier date of operation was a risk factor for death, but only in the case of the senior surgeon. Reinterventions were performed to relieve right ventricular and/or pulmonary artery stenoses alone in 28 patients. The hazard function for reintervention for pulmonary artery or valve stenosis revealed an early phase that peaked at 9 months after the operation and a constant phase for the duration of follow-up. Incremental risk factors for the early phase included multiple ventricular septal defects, the rapid two-stage arterial switch, and a coronary pattern with a single ostium supplying the right coronary and left anterior descending, with a retropulmonary course of the circumflex. The need for reintervention has decreased with time. The arterial switch operation can currently be performed early in life with a low mortality risk (< 5%) and a low incidence of reintervention (< 10%) for supravalvular pulmonary stenosis. The analyses indicate that both the mortality and reintervention risks are lower in patients with less complex anatomy.

Pain management and sedation in the pediatric intensive care unit

Several situations arise in the PICU patient that require the administration of drugs for sedation and analgesia. A "cookbook" approach is impossible because of the diversity of patient and clinical scenarios. When amnesia is required, these authors prefer a continuous infusion of a benzodiazepine such as midazolam or lorazepam. Although the majority of clinical experience has been with midazolam, lorazepam either by bolus dose or continuous infusion offers a cost-effective alternative. When analgesia is required, the addition of a continuous infusion of narcotic or the use of a PCA device in the older patient should prove effective. Although fentanyl is frequently chosen, morphine is an effective and cost-effective alternative for patients with stable cardiovascular function. The synthetic narcotics are recommended for neonates, especially following cardiac surgical procedures and those at risk for pulmonary vasospasm. Narcotics may also be used for the treatment of agitation in those situations that do not necessarily require analgesia. Our clinical experience suggests that narcotics may be more effective for sedation than benzodiazepines in children less than 1 year of age. When the above agents fail to be effective or are associated with cardiovascular depression, alternatives may include ketamine or pentobarbital. Ketamine may be useful for the unstable patient or those with a bronchospastic component to their disease process. We have found pentobarbital to be effective when the combination of benzodiazepines and narcotics fails to provide the desired level of sedation. Aside from these techniques, regional anesthesia may offer a more effective means of controlling pain in the PICU patient. These techniques may be effective when parenteral narcotics are inadequate or lead to undesired effects. Although most commonly used for postoperative analgesia, their use in patients with pain from other causes (e.g., multiple trauma) may be indicated, especially when parenteral narcotics may interfere with respiratory function or the ongoing assessment of the patient's mental status.

A comparison of the antinociceptive effects of opioid agonists in neonatal and adult rats in phasic and tonic nociceptive tests

Changes in the attitudes about neonatal pain and pain management have recently resulted in increases in the administration of opioids to neonates. Little is known, however, about the relative potencies of the various opioid agonists employed, especially in comparison to adult responses. The first objective in the present study was to compare the antinociceptive potency of four clinically relevant opioids in neonatal and adult rats. The second objective was to compare and contrast these agents in two different types of nociceptive tests: tonic (formalin-induced inflammation) and phasic (tail flick and hot plate). Our results indicate that the opioid agonists morphine, meperidine, and fentanyl, and the mixed agonist buprenorphine were all effective antinociceptive agents in both neonates and adults in each of the three tests employed, and that the relative potencies of these agents appeared to be similar in neonates and adults. In general, the pups were more sensitive to the antinociceptive agents when tested in the phasic nociceptive tests, and the drugs were more potent in the tonic test than either of the phasic tests.

Cardiac arrest and hypertrophic cardiomyopathy. Role of the implantable defibrillator

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Rocking and pacifiers: two comforting interventions for heelstick pain

The effects of behavioral interventions in reducing the stress of infant pain are not well documented. Two comfort interventions, rocking and pacifiers, were compared with routine care administered to 60 newborn infants randomly assigned to the three conditions following a neonatal screening heelstick. Heart rate, state of arousal, and crying were recorded continuously. Both pacifiers and rocking reduced crying, but pacifiers predominantly produced sleep states and rocking predominantly produced alert states. Pacifiers reduced heart rate levels significantly more than did rocking. Thus, newborns clearly benefit from both comforting methods. Several mechanisms are proposed to account for these findings.

Respiratory complications due to inadequate analgesia following thoracotomy in a neonate

We present a case in which a 2-day-old infant suffered respiratory complications shortly following premature termination of a postoperative extradural infusion. Restoration of analgesia led to a marked clinical improvement.