Prone equals prone? – impact of different techniques of body positioning on functional residual capacity and ventilation distribution in anaesthetised,paralysed preschool children

Introduction: In children undergoing anesthesia or sedation, optimizing functional residual capacity (FRC) is of special importance, because they have smaller elastic retraction forces compared with adults and a lower relaxation volume that makes them more prone to airway collapse. Moreover, children are particularly vulnerable to hypoxaemia because of their higher oxygen demand per kilo body weight. Although the prone position is effectively used to improve oxygenation, its impact on FRC is controversial. Thus, additional confounding factors such as changes in ventilation distribution or differences in positioning techniques might be of importance. In fact, positioning techniques such as flat versus augmented prone position could exert different degrees of pressure on the abdominal contents and thus differences in the cephalic displacement of the diaphragm. The aim of this study was to determine the impact of two different prone positioning techniques on FRC and ventilation distribution in anesthetized, paralyzed preschool‐aged children. We hypothesized that augmented prone positioning improves FRC and ventilation distribution compared with the supine or flat prone position. Methods: Following local Ethics Committee approval, 30 preschool children without cardiopulmonary disease undergoing elective surgery were studied. FRC and lung clearance index (LCI), a measure of ventilation distribution, were calculated using a sulfur‐hexafluoride gas (SF₆) multibreath washout technique. After intubation, the measurements were taken in the supine position and in random order in the flat prone and augmented prone position (gel pads supporting the pelvis and the upper thorax to ensure free movement of the abdomen). The position of the arms was kept constant and the head was turned to the side for all assessments. Measurements were taken 5 min after each positioning. Results: Mean (range) age was 48.5 (24–80) months, weight = 17.2 (10.5–26.9) kg. FRC (mean ± SD) was 22.9 ± 6.2 ml·kg^‐1 in the supine position and 23.3 ± 5.6 ml·kg^‐1 in the flat prone position while LCI was 8.1 ± 2.3 vs 7.9 ± 2.3 in these two positions, respectively. In contrast, FRC increased to 27.6 ± 6.5 ml·kg^‐1 (P < 0.001) in the augmented prone position while at the same time the LCI decreased to 6.7 ± 0.9 (P < 0.001). Conclusions: FRC and ventilation distribution were similar in the supine and flat prone positions, while these parameters improved significantly in the augmented prone position suggesting that the technique of prone positioning could have a major impact on respiratory function in anaesthetized, mechanically ventilated preschool children. Acknowledgement: The study was funded by the Department of Anaesthesia, University of Basel, Switzerland.     

Clonidine does not improve quality of ropivacaine axillary brachial plexus block in children

Background: The addition of clonidine to peripheral nerve blocks is controversial in children. Objective: The aim of our study was to evaluate the effect of clonidine added to ropivacaine in pediatric axillary brachial plexus block (ABPB). Methods: Children aged 1–6 years, scheduled to undergo forearm or hand surgery, were recruited into this prospective, double‐blind controlled trial. Patients were randomly allocated to receive an ABPB either with ropivacaine 0.2% 0.4 ml·kg^?1 plus saline in 1 ml (RS) or ropivacaine 0.2% 0.4 ml·kg^?1 plus clonidine 1 μg·kg^?1 in 1 ml (RC). Primary endpoints were quality of postoperative analgesia as assessed by pain scores and total 24‐h postoperative analgesia requirements. Secondary outcomes were time to first analgesia request and duration of motor blockade. Results: Sixty patients were recruited (n = 30 per group) into the study. Pain scores were comparable throughout the first 24 h between the two groups. Ten children in the (RS) and six in (RC) groups required supplementary analgesia during the first 24 h (P = 0.24). Children who required further analgesia did so after 288 ± 94 min in the (RS) and 437 ± 204 min in the (RC) group (P = 0.06). There was no difference in the duration of motor block [186 ± 71 and 154 ± 56 min, P = 0.12 for (RS) and (RC), respectively]. Conclusion: Ropivacaine (0.2% 0.4 ml·kg^?1) for ABPB provides sufficient postoperative analgesia in children scheduled for forearm or hand surgery. The addition of clonidine to ABPB does not improve overall postoperative analgesia but may increase the time to first analgesia request.     

Protective ventilation to reduce inflammatory injury from one lung ventilation in a piglet model

Objectives: To test the hypothesis that protective ventilation strategy (PVS) as defined by the use of low stretch ventilation (tidal volume of 5 ml·kg^?1 and employing 5 cm of positive end expiratory pressure (PEEP) during one lung ventilation (OLV) in piglets would result in reduced injury compared to a control group of piglets who received the conventional ventilation (tidal volume of 10 ml·kg^?1 and no PEEP). Background: PVS has been found to be beneficial in adults to minimize injury from OLV. We designed the current study to test the beneficial effects of PVS in a piglet model of OLV. Methods: Ten piglets each were assigned to either ‘Control’ group (tidal volume of 10 ml·kg^?1 and no PEEP) or ‘PVS’ group (tidal volume of 5 ml·kg^?1 during the OLV phase and PEEP of 5 cm of H₂O throughout the study). Experiment consisted of 30 min of baseline ventilation, 3 h of OLV, and again 30 min of bilateral ventilation. Respiratory parameters and proinflammatory markers were measured as outcome. Results: There was no difference in PaO₂ between groups. PaCO₂ (P < 0.01) and ventilatory rate (P < 0.01) were higher at 1.5 h OLV and at the end point in the PVS group. Peak inflating pressure (PIP) and pulmonary resistance were higher (P < 0.05) in the control group at 1.5 h OLV. tumor necrosis factor‐alpha (P < 0.04) and IL‐8 were less (P < 0.001) in the plasma from the PVS group, while IL‐6 and IL‐8 were less (P < 0.04) in the lung tissue from ventilated lungs in the PVS group. Conclusions: Based on this model, PVS decreases inflammatory injury both systemically and in the lung tissue with no adverse effect on oxygenation, ventilation, or lung function.     

Levobupivacaine–tramadol combination for caudal block in children: a randomized,double‐blinded,prospective study1

Background: The aim of this prospective study was to compare the postoperative analgesic efficacy and duration of analgesia after caudal levobupivacaine 0.125% or caudal tramadol 1.5 mg·kg⁻¹ and mixture of both in children undergoing day‐case surgery. Methods: Sixty‐three American Society of Anesthesiologists (ASA) I or II children between 1 and 7 years old scheduled for inguinal hernia repair under sevoflurane anesthesia were randomized to receive caudal levobupivacaine 0.125% (group L), caudal tramadol 1.5 mg·kg⁻¹ (group T) or mixture of both (group LT) (total volume of caudal solution was 1 ml·kg⁻¹). Duration of analgesia and requirement for additional analgesics were noted. Postoperative pain was evaluated using the Children’s and Infants’ Postoperative Pain Scale (CHIPPS) every 15 min for the first hour, and after 2, 3, 4, 6, 12, and 24 h. Analgesia was supplemented whenever pain score was ≥4. Results: No patient experienced significant intraoperative hemodynamic response to surgical incision. Duration of analgesia was significantly longer in group LT than in group L and group T (545 ± 160 min vs 322 ± 183 min and 248 ± 188 min, respectively) (P < 0.01). There were no significant differences between the group L and group T for duration of analgesia (P > 0.05). There were no significant differences among the groups in the number of patients requiring analgesia after operation (P = 0.7). No signs of motor block were observed after the first postoperative hour in any of the patients. Conclusion: Addition of tramadol increased the duration of analgesia produced by caudal levobupivacaine in children.     

Efficacy of bupivacaine‐neostigmine and bupivacaine‐tramadol in caudal block in pediatric inguinal herniorrhaphy

Background: Limited duration of analgesia is among the limitations of single caudal injection with local anesthetics. Therefore, the purpose of this study was to evaluate the effectiveness and safety of bupivacaine in combination with either neostigmine or tramadol for caudal block in children undergoing inguinal herniorrhaphy. Methods: In a double‐blinded randomized trial, sixty children undergoing inguinal herniorrhaphy were enrolled to receive a caudal block with either 0.25% bupivacaine (1 ml·kg^?1) with neostigmine (2 μg·kg^?1) (group BN) or tramadol (1 mg·kg^?1) (group BT). Hemodynamic variables, pain and sedation scores, additional analgesic requirements, and side effects were compared between two groups. Results: Duration of analgesia was longer in group BT (17.30 ± 8.24 h) compared with group BN (13.98 ± 10.03 h) (P = 0.03). Total consumption of rescue analgesic was significantly lower in group BT compared with group BN (P = 0.04). There were no significant differences in heart rate, mean arterial pressure, and oxygen saturation between groups. Adverse effects excluding the vomiting were not observed in any patients. Conclusion: In conclusion, tramadol (1 mg·kg^?1) compared with neostigmine (2 μg·kg^?1) might provide both prolonged duration of analgesia and extended time to first analgesic in caudal block.     

Unilateral groin surgery in children: will the addition of an ultrasound‐guided ilioinguinal nerve block enhance the duration of analgesia of a single‐shot caudal block?

Background: Inguinal hernia repair, hydrocelectomy, and orchidopexy are commonly performed surgical procedures in children. Postoperative pain control is usually provided with a single‐shot caudal block. Blockade of the ilioinguinal nerve may lead to additional analgesia. The aim of this double‐blind, randomized controlled trial was to evaluate the efficacy of an adjuvant blockade of the ilioinguinal nerve using ultrasound (US) guidance at the end of the procedure with local anesthetic vs normal saline and to explore the potential for prolongation of analgesia with decreased need for postoperative pain medication. Methods: Fifty children ages 1–6 years scheduled for unilateral inguinal hernia repair, hydrocelectomy, orchidopexy, or orchiectomy were prospectively randomized into one of two groups: Group S that received an US‐guided ilioinguinal nerve block with 0.1 ml·kg^?1 of preservative‐free normal saline and Group B that received an US‐guided nerve block with 0.1 ml·kg^?1 of 0.25% bupivacaine with 1 : 200 000 epinephrine at the conclusion of the surgery. After induction of anesthesia but prior to surgical incision, all patients received caudal anesthesia with 0.7 ml·kg^?1 of 0.125% bupivacaine with 1 : 200 000 epinephrine. Patients were observed by a blinded observer for (i) pain scores using the Children and Infants Postoperative Pain Scale, (ii) need for rescue medication in the PACU, (iii) need for oral pain medications given by the parents at home. Results: Forty‐eight patients, consisting of 46 males and two females, with a mean age of 3.98 (sd ± 1.88) were enrolled in the study. Two patients were excluded from the study because of study protocol violation and/or alteration in surgical procedure. The average pain scores reported for the entire duration spent in the recovery room for the caudal and caudal/ilioinguinal block groups were 1.92 (sd ± 1.59) and 1.18 (sd ± 1.31), respectively. The average pain score difference was 0.72 (sd ± 0.58) and was statistically significant (P < 0.05). In addition, when examined by procedure type, it was found that the difference in the average pain scores between the caudal and caudal/ilioinguinal block groups was statistically significant for the inguinal hernia repair patients (P < 0.05) but not for the other groin surgery patients (P = 0.13). For all groin surgery patients, six of the 23 patients in the caudal group and eight of the 25 patients in the caudal/ilioinguinal block group required pain rescue medications throughout their entire hospital stay or at home (P = 0.76). Overall, the caudal group received an average of 0.54 (sd ± 1.14) pain rescue medication doses, while the caudal/ilioinguinal block group received an average of 0.77 (sd ± 1.70) pain rescue medication doses; this was, however, not statistically significant (P = 0.58). Conclusions: The addition of an US‐guided ilioinguinal nerve block to a single‐shot caudal block decreases the severity of pain experienced by pediatric groin surgery patients. The decrease in pain scores were particularly pronounced in inguinal hernia repair patients.     

Isovolaemic hemodilution with gelatin and hydroxyethylstarch 130/0.42: effects on hemostasis in piglets

Objectives: Artificial colloids, frequently used to prevent hemorrhagic shock in children, impair blood coagulation. To determine the impact of acute isovolaemic hemodilution with artificial colloids on clot formation, we conducted an experimental study in a pediatric animal model. Methods: Fifteen piglets underwent hemorrhage by withdrawing 40 ml·kg^?1 of blood volume in steps of 10 ml·kg^?1 each within 1 hour. After each withdrawal, the blood loss was randomly compensated by administering 4% gelatin (GEL) or hydroxylethyl starch 130/0.42 (HES) in a ratio of 1 : 1, or isotonic crystalloid solution (ICS) in a ratio of 1 : 4 for isovolaemic hemodilution. Quality of clot formation and platelet function was measured using Thrombelastometry (ROTEM^®) and Multiple electrode impedance aggregometry (Multiplate^®) after 10, 20, and 40 ml·kg^?1 blood replacement. Results: Moderate hemodilution (10–20 ml·kg^?1 blood replacement) caused no significant differences among groups (e.g. INTEM^®‐MCF after 20 ml·kg^?1 blood replacement (ICS vs GEL vs HES, P > 0.05). Profound hemodilution with 40 ml·kg^?1 blood replacement showed a significant difference between ICS and both colloids (P < 0.05), but no significant differences between GEL and HES. Conclusions: Impairment of clot formation by moderate isovolaemic hemodilution did not significantly differ between ICS, GEL, and HES. Profound hemodilution of more than 50% of the estimated blood volume with GEL and HES caused significant impairment of clot formation in comparison to ICS and has to be considered when using high amounts of these synthetic colloids.     

Effects of olprinone on hepatosplanchnic circulation and mitochondrial oxidation in a porcine model of endotoxemia

Purpose This study was performed in order to assess the effects of olprinone, a phosphodiesterase III inhibitor, on hepatic oxygen delivery (DO₂H), oxygen consumption (VO₂H), and mitochondrial oxidation in the liver of a porcine endotoxemia model. Methods Fourteen pigs received continuous infusion of endotoxin via the portal vein for 240 min. From t = 150 to t = 240 min, animals were randomly divided into two groups to receive saline (control [CONT]; n = 7), or olprinone (OLP; n = 7) via the central vein. Results In the OLP group, prior to olprinone treatment at 150 min, endotoxin induced significant decreases in the cardiac index (CI; from 120 ± 31 to 65 ± 13 ml·kg⁻¹·min⁻¹; P < 0.01) and DO₂H (from 3.58 ± 0.81 to 1.55 ± 0.49 ml·kg⁻¹·min⁻¹; P < 0.01), while VO₂H was maintained. After administration of olprinone (from t = 150 to t = 240 min), CI was unchanged, while DO₂H increased from 1.55 ± 0.49 to 1.93 ± 0.38 ml·kg⁻¹·min⁻¹ (P < 0.01) and VO₂H increased from 0.42 ± 0.28 to 0.69 ± 0.38 ml·kg⁻¹·min⁻¹ (P < 0.01). At t = 240 min, the oxidation level of cytochrome aa3 was significantly higher in the OLP group than in the CONT group (OLP, 66.2 ± 19.3% vs CONT, 26.4 ± 17.3%; P < 0.01). Conclusion Our data for this porcine endotoxemia model suggest that olprinone may have beneficial therapeutic effects in restoring not only systemic and hepatic circulation but also mitochondrial oxidation in the liver.     

Hemostatic consequences of a non-fresh or reconstituted whole blood small volume cardiopulmonary bypass prime in neonates and infants

Objectives: Despite aggressive measures to miniaturize the cardiopulmonary bypass (CPB) circuit in neonates and infants, the CPB prime volume is often at least as large as the patients’ blood volume. We conducted an observational study to characterize the hemostatic consequences of a CPB prime consisting of either non‐fresh or reconstituted whole blood. Methods: Hematocrit, fibrinogen, platelet count, plasminogen, anti‐thrombin III (AT‐III), and factors (F) II, V, VII, IX, and X of 30 neonates and infants undergoing cardiac surgery with CPB utilizing either a non‐fresh or reconstituted whole blood prime were prospectively evaluated at eight time points. Following protamine administration, microvascular bleeding was treated by protocol. Results: The hemostatic composition of the CPB prime was the same following the use of either non‐fresh or reconstituted whole blood. The CPB prime platelet count (mean ± sd ) was 5.87 ± 2.84 × 10³ μl^?1 when compared to a preoperative platelet count of 298 ± 142 × 10³ μl^?1 (P < 0.0001). Twenty patients received 17.3 ± 9.2 ml·kg^?1 (0.86 ± 0.46 units·kg^?1) of platelets with significant improvement in platelet count. Nine patients received 16.7 ± 13.4 ml·kg^?1 (0.84 ± 0.67 units·kg^?1) of cryoprecipitate with significant improvements in FVIII and fibrinogen. Conclusions: Non‐fresh or reconstituted whole blood as a component of a small volume CPB prime in neonates and infants induces clinically significant dilutional thrombocytopenia in conjunction with less significant reductions in fibrinogen, FII, FV, FVII, FVIII, FIX, FX, plasminogen, and AT‐III.     

Reduction of blood loss using aprotonin during spinal surgery in children for non-idiopathic scoliosis.

Background Aprotinin, a serine protease inhibitor, reduces surgical blood loss by mechanisms including antifibrinolysis and preservation of platelet function. Its effectiveness has been reported in adult patients undergoing cardiac, major orthopaedic surgery (1) and liver surgery, as well as in paediatric cardiac surgery. Spinal surgery in children with scoliotic deformities involves major blood loss. This may often be more than one circulatory blood volume and therefore results in exposure to blood products and the accompanying risks and problems. Patients with Duchenne muscular dystrophy or other neuromuscular conditions presenting for correction of a spinal deformity pose a particular problem because of their propensity to bleed during surgery. Aprotinin was introduced into the RMCH for the purpose of reducing blood loss in this group of patients in 1999. Administration of aprotinin carries the risk of the formation of aprotinin specific antibodies and anaphylaxis. Re‐exposure carries a greater risk. The aim of this study was to investigate the effect of aprotinin on blood loss during corrective spinal surgery in the neuromuscular patients. Methods We have performed a retrospective review of 33 ASA III cases operated on in period June 1998–September 2000. All notes were studied and data recorded on the intraoperative blood loss and the length of surgical procedure. Aprotinin was used only in children where it was felt that they would be unlikely to be re‐exposed because of their initial presenting diagnosis. Our regimen for aprotinin administration was: test dose 5 ml (50 000 KIU) over 20 min, loading dose 2 ml·kg^?1 (20 000 KIU·kg^?1) infused over 30 min, then maintenance at 0.5 ml·kg^?1·hr^?1 (5 000 KIU·kg^?1·h^?1). Results In the group that had not received aprotinin were 15 patients aged 7–17 years (mean age 13 ± 2 years), measured blood loss was 2849 ± 1802 ml, length of surgery 343 ± 78 min. In the aprotinin group we had 18 patients aged 7–15 years (mean age 12 ± 2 years) with recorded mean blood loss of 1380 ± 1000 ml and duration of procedure 389 ± 142 min. The blood loss in the group that had received aprotinin was significantly reduced (P < 0.01). Discussion Our two groups of patients were similar regarding the age of patients, pathology and clinical presentation. We believe that the use of aprotinin resulted in significant reduction of blood loss and requirements for blood products.     

Measuring circulating blood volume in newborn infants using pulse dye densitometry and indocyanine green

Background: Circulating blood volume (BV) is an important, but often unconsidered, variable in newborn infants undergoing intensive care. The data on validation and repeatability of BV measurement are limited. Aim: To validate and test the repeatability of measuring BV in newborn infants using indocyanine green (ICG) and pulse dye densitometry (PDD). Methods: Validation– Paired measurements of BV were made using the fetal hemoglobin (HbF) dilution and the PDD method. Repeatability– The BV was measured twice at an interval of 30–40 min in a second group of infants. Results: Validation– Data from three of 13 infants studied were excluded because of probe dislodgement or ICG injection error. The median (range) birth weight of the 10 infants whose data were analyzed was 1032 g (740–2384 g) and seven (70%) were receiving either mechanical ventilation or nasal CPAP. The median BV measured by HbF dilution was 66.2 ml·kg^?1 (43.7–81.0 ml·kg^?1) and by the PDD method was 68.9 ml·kg^?1 (49.3–101.0 ml·kg^?1). The mean difference was 5.92 ml·kg^?1 (sd 17.33 ml·kg^?1). Repeatability– Twelve infants were studied and three excluded because of probe dislodgement/motion artifact or ICG injection error. The median weight of the nine infants whose data were analyzed was 1208 g (795–2600 g). The median (range) BV1 and BV2 were 70.5 ml·kg^?1 (53.1–160 ml·kg^?1) and 87.5 ml·kg^?1 (38.0–248.0 ml·kg^?1), respectively. Mean difference of the two BV estimates (BV1–BV2) was ?24.6 ml·kg^?1 (sd 33.3 ml·kg^?1) and coefficient of repeatability was 66.5 ml·kg^?1. Conclusion: Pulse dye densitometry can be used to measure BV in the newborn infant at the cotside but the repeatability measurements suggest that its use is limited.     

Alterations of acid-base balance, electrolyte concentrations, and osmolality caused by nonionic hyperosmolar contrast medium during pediatric cardiac catheterization

Objective: This prospective clinical observational study was conducted to investigate the effects of contrast medium on acid–base balance, electrolyte concentrations, and osmolality in children. Background:  For pediatric cardiac catheterization, high doses of nonionic hyperosmolar contrast medium are widely used. Methods: Forty pediatric patients (age 0–16 years) undergoing cardiac angiography with more than 3 ml·kg^?1 of nonionic hyperosmolar contrast medium (Iomeprol) were enrolled, and the total amount of the contrast agent given was documented. Before and after contrast medium administration, a blood sample was collected to analyze electrolytes, acid–base parameters, osmolality, hemoglobin, and hematocrit. Results: After cardiac catheterization, pH, hemoglobin, hematocrit, bicarbonate, base excess, sodium, chloride, calcium, anion gap and strong ion difference decreased, whereas osmolality increased significantly (base excess ?1.8 ± 1.8 vs ?3.4 ± 2.3, sodium 138 ± 2.9 vs 132 ± 4.1 mm , osmolality 284 ± 5.7 vs 294 ± 7.6 mosmol·kg^?1, P < 0.01). Seventy‐eight percent of the children developed hyponatremia (sodium <135 mm ). No changes were seen in pCO₂, lactate, and potassium levels. Conclusions: Regarding the differential diagnosis of metabolic disturbances after pediatric cardiac catheterization, low‐anion gap metabolic acidosis and hyponatremia should be considered as a possible side effect of the administered contrast medium.     

Ketamine as an adjunct to fentanyl improves postoperative analgesia and hastens discharge in children following tonsillectomy - a prospective, double-blinded, randomized study

Objective: To evaluate the effect of ketamine, as an adjunct to fentanyl, on postoperative analgesia and duration of Postoperative Care Unit (PACU) stay, in children undergoing tonsillectomy. Background: Ketamine, as an N‐methyl‐d ‐aspartate antagonist, has been recognized to have an opioid sparing effect. In addition, it does not depress respiration or affect airway tone. Hence, addition of ketamine could be potentially beneficial in children undergoing tonsillectomy, due to the high incidence of sleep apnea in these patients. Methods: In a double blinded, randomized trial, 60 ASA status I and II children between 2 and 7 years of age, scheduled to undergo elective tonsillectomy were recruited. They were randomly assigned to one of four groups to receive fentanyl 1 mcg·kg^?1 (F1 group), fentanyl 2 mcg·kg^?1 (F2 group), ketamine 0.5 mg·kg^?1 (K group), or fentanyl 1 mcg·kg^?1 plus ketamine 0.5 mg·kg^?1 (FK group) pre‐incision. Postoperative pain was scored on arrival to the PACU and at 30, 60, and 90 min thereafter. Any incidence of nausea/vomiting and time to discharge from the PACU were also recorded. Results: Important predictors found for postoperative pain on arrival to the recovery room are the group (P = 0.02) and duration of surgery (P = 0.02). Least square means and standard errors of pain scores on PACU arrival were 4.87±0.69, 3.04±0.68, 2.10±0.68 and 2.03±0.69 for F1, F2, K and FK groups, respectively. On group‐wise comparison adjusted for surgical time, significant difference was detected between F1 and K (P = 0.02), and F1 and FK (P = 0.0048) groups. Marginal significance was detected in duration of PACU stay among groups (P = 0.08); F2 and FK group had a shorter PACU stay than F1 (P = 0.05 and 0.04 respectively). No significant difference was detected in the need for supplemental analgesia. Conclusion: We conclude that the administration of ketamine 0.5 mg·kg^?1 with 1 mcg·kg^?1 fentanyl in children undergoing tonsillectomy may improve postoperative pain control without delaying home discharge.     

Analgesia for adenotonsillectomy in children: a comparison of morphine, ketamine and tramadol

Background : Establishment of good analgesia is of major concern in the postoperative period following adenotonsillectomy. The aim of this study was to compare the effects of ketamine, morphine and tramadol on postoperative pain after adenotonsillectomy in children. Methods : Sixty children (age 5–12 years) scheduled for adenotonsillectomy were randomized into four groups to receive intravenously (i.v.) either 0.5 mg·kg^?1 ketamine hydrochloride (K), 0.1 mg·kg^?1 morphine hydrochloride (M), 1.5 mg·kg^?1 tramadol hydrochloride (T) or normal saline (S) in a volume of 4 ml during induction. After tracheal intubation 10 μg·kg^?1·min^?1 ketamine hydrochloride in group K and 0.6 ml·kg^?1·h^?1 saline i.v. in groups M, K and S were infused peroperatively. Postoperative analgesic requirements and side‐effects were recorded. Pain was assessed by the Numeric Rating Scale (NRS) and the Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) scores. Results : Heart rate increased significantly peroperatively only in group K. NRS at first and fifth minute in group M and at first minute in group T and K and CHEOPS score at first, fifth, 15th and 60th min in group M were found to be significantly lower than in the control group. The time to first analgesic requirement was significantly longer in group M compared with ketamine and the control group. Six children in group M, nine in group T, 11 in group K and 15 in group S needed additional analgesics. Conclusions : Morphine hydrochloride 0.1 mg·kg^?1 i.v. administered during induction of anaesthesia provides efficient pain relief in children undergoing adenotonsillectomy.     

The effect of volume of local anesthetic on the anatomic spread of caudal block in children aged 1-7 years

Objectives: To examine the anatomic spread of caudal local anesthetic solution in children aged 1–7 years. Aim: To determine whether incremental increases in the volume of caudal injections of 0.5, 0.75, and 1.0 ml·kg^?1 result in reliable (>90%) and potentially clinically significant increases in the number of vertebral segments reached. Background: Caudal block is one of the most frequently performed pediatric regional analgesic techniques. Traditional formulae suggest that changes in the volume of caudal injectate in the range 0.5–1.0 ml·kg^?1 would have clinically useful effects. Methods: In a single blind design, 45 children aged 1–7 years undergoing caudal block received one of the three predetermined volumes (0.5, 0.75, and 1 ml·kg^?1) of local anesthetic solution containing radio‐opaque contrast under controlled conditions. Following X‐ray examination, the anatomic spread of the block was reported by a radiologist blinded to the volume of solution received. Results: There were 15 children in each group, and they were similar in terms of age, height, and weight. Spread was observed between the 5th lumbar (L5) and 12th thoracic (T12) vertebral levels. A volume of 1 ml·kg^?1 results in a small but significantly greater spread of solution than 0.5 ml·kg^?1 (P < 0.05), but there was no difference between 0.5 and 0.75 ml or between 0.75 and 1.0 ml. No volume reliably reached a level higher than the second lumbar vertebra (L2). Conclusions: Incrementally increasing the volume of injectate between 0.5 and 1.0 results in a modest increase in the spread of the caudal solution. It is unlikely that volumes of <1 ml will reliably reach a vertebral level that is higher than L2.     

Subarachnoid bupivacaine decreases spinal cord blood flow in dogs

Eigtheen mongrel dogs were randomized into two equal groups. Cervical, thoracic and lumbosacral spinal cord and spinal dural blood flows were measured using the radioactive microsphere technique. Blood flow determinations were made prior to, and 20 and 40 minutes following lumbar subarachnoid injection of: (1) 0.4 per cent bupivacaine (20 mg), or (2)0.4 per cent bupivacaine (20 mg) with 1/25,000 epinephrine (200 μg). In dogs given subarachnoid bupivacaine or bupivacaine with epinephrine, the maximum decrease in mean arterial blood pressure (33 per cent) occurred at 40 minutes post-injection. Cardiac index decreased in dogs given subarachnoid bupivacaine (197 ± 11 ml·kg^-1·min^-1 controlvs. 141 ± 19 ml·kg^-1 min^-1 at 40 minutes), while it increased in dogs given bupivacaine with epinephrine (201 ± 11ml·kg^-1·min^-1 - control vs. 252 ± 15 ml · kg^-1 · min^-1 at 40 minutes). Dogs receiving subarachnoid bupivacaine demonstrated a significant decrease in spinal cord blood flow to all regions. Dogs receiving subarachnoid bupivacaine with epinephrine demonstrated a significant decrease in thoracic and lumbosacral spinal cord blood flow; however, cervical cord blood flow remained unchanged. Thoracic and lumbosacral dural blood flows were significantly decreased in both groups following subarachnoid injection. Subarachnoid bupivacaine 0.4 per cent (20 mg) and 0.4 per cent with epinephrine 1/25,000 (200 μg) decrease spinal cord and spinal dural blood flow in dogs.     

Reduced-dose rocuronium for day-case tonsillectomy in children where volatile anaesthetics are not used: operating room time saving

Objectives: Mivacurium, rocuronium, and vecuronium are neuromuscular blocking agents (NMB) commonly used in pediatric day‐case anesthesia. Mivacurium is the most appropriate NMB for short surgical procedures where NMB drugs were required but is not available in all countries. Aim: We evaluated the operating room time minimization after reduced‐dose rocuronium (0.45 mg·kg^?1) during elective day‐case tonsillectomy in children. Methods/Materials: One hundred and five children (6–9 years, ASA I/II status) scheduled for day‐case tonsillectomy were included in prospective, double blind clinical study. Children were randomly divided in three equal groups. All children were premedicated (midazolam 0.25 mg·kg^?1 orally, EMLA). Anesthesia was induced (2.5 mg·kg^?1) and maintained (0.1 mg·kg^?1·min^?2) by propofol and alfentanil (0.0015 mg·kg^?1·min^?1) and supplemented by inhalation mixture of 50% of O2/Air. Neuromuscular block was achieved by vecuronium (0.1 mg·kg^?1) (V) or rocuronium in standard (0.6 mg·kg^?1) (R) or reduced dose (0.45 mg·kg^?1) (LD). Neuromuscular transmission was monitored by acceleromyography. Time analysis of NMB drugs action was performed. Results: Time difference from the end of tonsillectomy to T90 neuromuscular block recovery was significantly shorter in LD Group (7.3 ± 0.41 min), (V = 15.9 ± 1.06, R = 16.0 ± 1.7 min) (P = 0.0011). The onset time of neuromuscular block was prolonged in LD Group (LD=3.1 ± 0.4, R = 1.3 ± 0.4, V = 2.2 ± 0.2 min) (P = 0.0039) without changing the intubating conditions. The maximum operation room time saving per each tonsillectomy was 37% in LD Group (Group V 21%, Group R 17%) (P = 0.0001). Low incidence of postoperative nausea and vomiting (PONV) 3–6% (0.4577) and good visual analog scale (VAS) score (≤2) (0.5969) were found in all study groups 12 h after surgery. Conclusions: Reduced‐dose rocuronium in addition with propofol and alfentanil in children where volatile anesthetics are not used effectively saves the operating room time during short elective surgical procedures, avoids delays in patient recovery, allows high level of acceptable intubating conditions, and improves the optimal surgical work. Low incidences of PONV as VAS score may achieved successfully.     

Resuscitation strategies from bupivacaine-induced cardiac arrest

Objectives: Local anesthetic (LA) intoxication with cardiovascular arrest is a potential fatal complication of regional anesthesia. Lipid resuscitation has been recommended for the treatment of LA‐induced cardiac arrest. Aim of the study was to compare four different rescue regimens using epinephrine and/or lipid emulsion and vasopressin to treat cardiac arrest caused by bupivacaine intoxication. Methods: Twenty‐eight piglets were randomized into four groups (4 × 7), anesthetized with sevoflurane, intubated, and ventilated. Bupivacaine was infused with a syringe driver via central venous catheter at a rate of 1 mg·kg^?1·min^?1 until circulatory arrest. Bupivacaine infusion and sevoflurane were then stopped, chest compression was started, and the pigs were ventilated with 100% oxygen. After 1 min, epinephrine 10 μg·kg^?1 (group 1), Intralipid^® 20% 4 ml·kg^?1 (group 2), epinephrine 10 μg·kg^?1 + Intralipid^® 4 ml·kg^?1 (group 3) or 2 IU vasopressin + Intralipid^® 4 ml·kg^?1 (group 4) were administered. Secondary epinephrine doses were given after 5 min if required. Results: Survival was 71%, 29%, 86%, and 57% in groups 1, 2, 3, and 4. Return of spontaneous circulation was regained only by initial administration of epinephrine alone or in combination with Intralipid^®. Piglets receiving the combination therapy survived without further epinephrine support. In contrast, in groups 2 and 4, return of spontaneous circulation was only achieved after secondary epinephrine rescue. Conclusions: In cardiac arrest caused by bupivacaine intoxication, first‐line rescue with epinephrine and epinephrine + Intralipid^® was more effective with regard to survival than Intralipid^® alone and vasopressin + Intralipid^® in this pig model.     

Before-after study of a restricted fluid infusion strategy for management of donor hepatectomy for living-donor liver transplantation

Purpose  Intraoperative fluid infusion strategy remains controversial. Many animal model studies have shown that restricted fluid infusion reduces blood loss, though reports on this topic in humans are rare. The purpose of this study was to determine the effects on volume of blood loss of a restricted fluid infusion strategy for hepatectomy in donors for livingdonor liver transplantation. Methods  A before-after study design was used with prospective consecutive data collection. A total of 22 patients who underwent living-donor hepatectomy were enrolled. Eleven patients who were managed before the implementation of restricted-volume fluid administration comprised the standard-volume group, and 11 who were evaluated after the implementation of the restricted-volume infusion strategy comprised the restricted-volume group. In the standard-volume group, the donors were given 10 ml·kg⁻¹·h⁻¹ of lactated Ringer’s solution and additional plasma expander corresponding to blood loss. In the restricted-volume group, the donors received 5 ml·kg⁻¹·h⁻¹ of lactated Ringer’s solution until the resection of the hepatic graft, followed by 15 ml·kg⁻¹·h⁻¹ of lactated Ringer’s solution after the completion of resection until the end of the operation. Results  Intraoperative blood loss was less in the restricted-volume group (445 ± 193 ml) than in the standard-volume group (1331 ± 602 ml; P < 0.01). Intraoperative fluid infusion was also less in the restricted-volume group (4130 ± 563 ml) than in the standard-volume group (5634 ± 1260 ml; P < 0.01). There were no differences in length of hospital stay or side effects between the two groups. Conclusion  Our restricted-volume strategy reduced blood loss and had no adverse effects during living-donor hepatectomy.     

Radiological and clinical distribution of thoracic paravertebral blockade in infants and children

The radiological distribution of thoracic paravertebral blockade was studied by chest radiographs with radio-opaque dye injection in 18 paediatric patients. Two distinct patterns of distribution were found: longitudinal and cloudlike. Linear regression analysis found a strong correlation between the relative injected volume of radio-opaque dye and the number of covered segments for the longitudinal group (r= 0.92; number of segments = 3.19 + 14.49 × ml·kg^?1) whereas a moderate correlation was found for the cloudlike group (r= 0.47; number of segments = 3.27 + 3.21 × ml·kg^?1). An injected volume of 0.25 (SD 0.12) ml·kg^?1 of radio-opaque dye was found to cover 5.7 (SD 1.6) segments. In no case could spread to the extradural space be found. The clinical distribution of the blocks was examined in a small number of patients and was found to extend from dematome Th 3/4 to Th 12. An initial bolus dose of 0.5 ml·kg^?1 of the local anaesthetic solution is advocated in order to cover reliably at least five segments which would be sufficient in most clinical situations.