The effects of cardiopulmonary bypass on postoperative oxygen metabolism

The relationships between oxygen delivery (DO₂), oxygen consumption (VO₂), and the extraction rate (ER=VO₂/DO₂x100) in patients undergoing cardiopulmonary bypass (CPB) may differ from the normal physiologic state due to the oxygen debt acquired during CPB. Blood gas analysis and hemodynamic parameters were repeatedly measured for the determination of DO₂ and VO₂ in 40 patients undergoing CPB, every 8h during the first 48h postoperatively. As a control, 20 patients who had suffered acute myocardial infarction (AMI) were also studied using the same protocol. In the CPB group, a regression analysis showed that VO₂ was significantly dependent on DO₂, even within the physiologic range of DO₂ (>500 ml/min per m²); VO₂=121.4+0.0844×DO₂ (r=0.254,P=0.023). Conversely, in the AMI group, no such supply-dependent consumption was observed within the same range of DO₂. At an ER of 30%, which is the optimal value in general, the DO₂ of the CPB group was 575 ml/min per m² and that of the AMI group was 493 ml/min per m². All these results suggest that patients undergoing CPB need a much higher oxygen supply to recover from the oxygen debt acquired during open heart surgery.     

Correlation between central venous oxygen saturation and oxygen delivery changes following fluid therapy

Background: The rationale for using central venous oxygen saturation (ScvO₂) in various clinical scenarios is that it reflects the balance between oxygen delivery (DO₂) and demands. In this study, we evaluated the correlation between ScvO₂ and DO₂ changes (ΔDo₂, ΔScvO₂) in patients receiving fluid therapy following coronary surgery. We also correlated the changes of mean arterial pressure (ΔMAP) and central venous pressure (ΔCVP), with ΔDO₂. Methods: Sixty consecutive sedated and mechanically ventilated adult patients, with cardiac index ≤2.3 L/min/m² and a pulmonary artery occlusion pressure ≤12 mmHg following coronary surgery, were included. Concomitant hemodynamic parameters, arterial and venous blood gases were measured before (T0) and after (T1) administration of a 500 ml bolus of an isotonic crystalloid solution over 30 min. The correlations between ΔDO₂ and ΔScvO₂, ΔMAP or ΔCVP were evaluated by linear regression analysis and Pearson test. Results: Cardiac index (1.9±0.2 vs 2.3±0.5 ml/min/m²), MAP (83±11 vs 94±13mmHg) and CVP (5.7±3 vs 7.1±3 mmHg) were significantly higher at T1 compared with T0. The correlation of ΔDO₂ with ΔScvO₂ was positive, significant (r=0.41; P=0.004) and superior to its correlation with ΔMAP (r=0.30; P=0.01) or ΔCVP (r=0.03; P=0.78). Conclusion: A significant correlation between ScvO₂ and DO₂ changes was found in patients receiving fluid therapy following coronary surgery. ScvO₂ could be used as an indicator to track DO₂ and to guide volume loading.     

Nitric oxide inhalation increases oxygen delivery after cardiovascular surgery in adult patients whether or not they have pulmonary hypertension

Purpose The purpose of this study was to quantify the increase in oxygen delivery (DO₂) produced by nitric oxide (NO) inhalation, and to clarify whether NO inhalation might be effective in adult patients after cardiovascular surgery whether or not they have pulmonary hypertension (PH). Methods The study was done on 26 adult patients after cardiovascular surgery. The indications for NO inhalation were postoperative hypoxic respiratory failure (POHRF) with or without PH. NO was administered via a premixing system or via a side-stream system. The dose was adjusted to between 1 and 10 (5.7±2.0) (mean±SD) ppm. Data were obtained just before and within 120 min after the initiation of NO inhalation. We initially analyzed the data from all the patients together and then compared data from two groups made up from just 22 of the 26 patients: 14 patients without PH whose PaO₂/FiO₂ before NO inhalation was less than 200 mmHg (simple POHRF group), and 8 patients who had both POHRF and PH (systolic pulmonary arterial pressure higher than 40 mmHg) (POHRF with PH group). Results In the original group of 26 patients, significant improvements were observed in PaO₂, PaO₂/FiO₂, CI, SPAP, CaO₂, DO₂I, and SvO₂ during NO inhalation. The increase in DO₂I was 68 ml·min⁻¹·m⁻² (+19.5%). PaO₂, PaO₂/FiO₂, CaO₂, DO₂I, and SvO₂ increased significantly in both groups. The increase in DO₂I was 60 ml·min⁻¹·m⁻² (+18.9%) in the simple POPHRF group and 79ml·min⁻¹·m⁻² (+18.0%) in the POHRF with PH group. Conclusion NO inhalation increases DO₂ by approximately 20% in adult patients after cardiovascular surgery, irrespective of whether or not they have pulmonary hypertension.     

Two different doses of caudal neostigmine co-administered with levobupivacaine produces analgesia in children

Background: This study was aimed to evaluate the analgesic efficacy, duration of analgesia, and side effects of two different doses of caudal neostigmine used with levobupivacaine in children. Methods: Sixty boys, between 5 months and 5 years, undergoing genito‐urinary surgery were allocated randomly to one of three groups (n = 20 each). Group I patients received caudal 0.25% levobupivacaine (1 ml·kg^?1) alone. Groups II and III patients received neostigmine (2 and 4 μg·kg^?1 respectively) together with levobupivacaine used in the same dose as Group I. Pain scores were assessed using Children’s and Infant’s Postoperative Pain Scale (CHIPPS) at 15th (t₁) min after arrival to postanesthetic care unit, and 1st (t₂), 2nd (t₃), 3rd (t₄), 4th (t₅), 8th (t₆), 16th (t₇), and 24th (t₈) hour postoperatively. Duration of analgesia, amount of additional analgesic (paracetamol), score of motor blockade and complications were recorded for 24 h postoperatively, and compared between groups. Results: CHIPPS scores were higher during t₂, t₃, t₆, t₇ and t₈ periods, duration of analgesia was shorter, and total analgesic consumption was higher in Group I compare to neostigmine groups (P < 0.05). Duration of postoperative analgesia and total analgesic consumption were similar in Groups II and III (P > 0.05). Adverse effects were not different between three groups. Conclusions: Caudal neostigmine in doses of 2 and 4 μg·kg^?1 with levobupivacaine extends the duration of analgesia without increasing the incidence of adverse effects, and 2 μg·kg^?1 seems to be the optimal dose, as higher dose has no further advantages.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.     

Validation of the Center for Medicare and Medicaid Services algorithm for eligibility for dialysis

The Center for Medicaid and Medicare Services (CMS) has recently revised their end-stage renal disease (ESRD) Medical Evidence Report, Medicare Entitlement, and Patient Registration CMS 2728 Form. The modified algorithm calls for the use of formulae to estimate glomerular filtration rate (GFR). The new criterion is defined as estimated GFR of less than 20 ml/min per 1.73 m². GFR is either estimated by Schwartz formula (C_SCH) in children or Modification of Diet in Renal Disease formula (C_MDRD) in adults. The purpose of this communication is to test the validity of the new CMS GFR algorithm in detecting children who need renal replacement therapy. We evaluated two cohorts of children. Group I included single-center data from 626 ¹²⁵I-iothalamate clearance studies (C_IO) that were compared with the simultaneous estimation of GFR by C_SCH. Group II included data on 659 children from the patient incidence registry obtained from the ESRD Network of Texas between February 1996 and October 2003. In group I there were 76 children (76 C_IO) with C_SCH less than 20 ml/min per 1.73 m² of whom 50 (67%) had C_IO less than 15 ml/min per 1.73 m². Of children with C_IO less than 15 ml/min per 1.73 m², 62% had a C_SCH less than 20 ml/min per 1.73 m². The ability of C_SCH greater than 20 ml/min per 1.73m² to predict C_IO greater than 15 ml/min per 1.73 m² (negative predictive value) is 0.95. The number of children who were started on dialysis in Texas within the study period was 659 (group II). The mean C_SCH±SD was 10.8±7.7 ml/min per 1.73 m². Of the patients who were initiated on dialysis, 94% had C_SCH less than 20 ml/min per 1.73 m². The results were sustained when race, gender, age range, and type of diagnosis were considered. The new CMS algorithm provides a good negative predictive estimate of GFR less than 15 ml/min per 1.73 m². Disclaimer The analyses upon which this publication is based were performed under contract number 500–03-NW14 entitled End-Stage Renal Disease Networks Organization for the State Texas, sponsored by the Centers for Medicare and Medicaid Services, Department of Health and Human Services. The content of this publication does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government. The authors assume full responsibility for the accuracy and completeness of the ideas presented. This article is a direct result of the Health Care Quality Improvement Program initiated by the Centers for Medicare and Medicaid Services, which has encouraged identification of quality improvement projects derived from analysis of patterns of care, and therefore required no special funding on the part of this contractor. Ideas and contributions to the author concerning experience in engaging with issues presented are welcomed.     

Global tissue oxygenation during normovolaemic haemodilution in young children

Sixteen patients (1–8 years) scheduled for major general surgery were chosen for the study. They were divided into two groups according to the replacement solution used for haemodilution (HD); whether 6% middle molecular weight hydroxyethyl starch (HES) or 6% dextran 60 (DEX). After induction of general anaesthesia and pulmonary artery catheterization, a precalculated amount of autologous blood was withdrawn while the patient's autologous blood was simultaneously replaced by either HES or DEX. Autologous blood was retransfused at a minimum haematocrit (Hct.) of 17% or at the end of surgery. The following parameters were measured and/or calculated before and after HD, every 20 min intraoperatively and hourly for 6 h postoperatively: heart rate (HR), mean arterial pressure (MAP), Cardiac index (CI), Hct., arterial and mixed venous oxygen content (CaO₂, CvO₂) and arterio-venous difference of oxygen content (avDO₂), oxygen delivery index (DO₂I), oxygen consumption index (VO₂I). The cardiovascular system remained stable. There was no significant difference as regards SvO₂, despite a significant decrease in CaO₂ to 10.8 and 10.0 ml·dl^?1 (median values) due to reduction of haemoglobin concentration in the HES and DEX groups respectively. In spite of the low hct. values during surgery DO₂I remained in normal range (median value 602 and 710 ml·min^?1·m^?2) in HEX and DEX group respectively. There was no significant change in VO₂I after haemodilution (median value 212 and 243 ml.min^?1·m^?2) in either group. No statistically significant difference was noticed between either groups regarding: CaO₂, CvO₂, DO₂I, VO₂I, and no side effects of the colloids were observed. Isovolaemic haemodilution (Hct. approx;17%) is well tolerated by young children undergoing major elective surgery; global tissue oxygenation was preserved throughout the procedure and both solutions used for haemodilution were equally effective.     

Epidural administered buprenorphine in the perioperative period

Purpose

To study the effect of epidural buprenorphine on minimum alveolar concentration (MAC) of volatile anaesthetics, duration of analgesia and respiratory function in the perioperative period.

Methods

One hundred and twenty patients, ASA I–II undergoing gynaecological surgery were randomly divided into three studies. The forty patients in each study were randomly divided into four groups depending on the dosage; Group I (control), Group II (80 μg · kg^?1 morphine), Group III (4 μg · kg^?1 buprenorphine), Group IV (8 μg · kg^?1 buprenorphine). The MAC of halothane was measured following epidural administration of the agents in each group. The duration of analgesia was assessed by the first request for pentazocine. Postoperative analgesic effects were assessed by the total dosage of pentazocine required for the 48 hr after surgery. Respiratory rate (RR), minute volume (MV), and PaCO₂ were measured during surgery and the postoperative period. The MAC of halothane was reduced in Group IV (P < 0.01). The duration of analgesia was 10.0 ± 5.1 hr (Mean ± SE) in Group 1, 37.7 ± 4.7 hr in Group II, 27.1 ± 7.1 hr in Group III, and 44.4 ± 4.1 hr in Group IV. Total dosage of pentazocine was lower in Group IV (P < 0.05) than in the other groups. The decrease of RR, MV and the increase of PaCO₂ were observed within 60 min in Group III and IV dose dependently.

Conclusion

Epidural buprenorphine administered in a dose of 4 or 8 μg · kg^?1 provides postoperative analgesia that is no less effective than that of morphine.     

Retrospective analysis of anesthetic interventions for obese patients undergoing elective cesarean delivery

Study ObjectiveTo examine the relationship between body mass index (BMI), perioperative times, and anesthetic interventions in patients undergoing elective cesarean delivery.DesignRetrospective chart review.SettingUniversity-affiliated hospital.MeasurementsAll patients were ranked according to BMI (kg/m²) at the time of delivery. The BMI groups were designated a priori: ≤ 29.9 kg/m² (Group C); 30-34.9 kg/m² (Group I); 35-39.9 kg/m² (Group II), and ≥ 40 kg/m² (Group III). One hundred patients (25 pts per group) underwent elective cesarean delivery. Data collected included anesthetic technique, perioperative times, anesthesia-related costs, and neonatal outcomes.Main ResultsA higher percentage of Group III patients (60%) received combined spinal-epidural (CSE) anesthesia than did Group C or Group I (18% and 16%, respectively; P < 0.05). The total intraoperative period was significantly longer in Group III (101 min) compared with Groups C, I, and II (81 min, 90 min, and 92 min, respectively; P < 0.05). Total intraoperative time increased significantly with BMI (R = 0.394 kg/m²; P < 0.001). The highest anesthesia-related costs during the study were generated by patients with BMI ≥ 40 kg/m².ConclusionOur single-center experience showed that choice of anesthetic technique (CSE vs. spinal anesthesia) varies according to obesity class. Longer intraoperative periods must be considered in deciding upon the mode of anesthesia for patients with BMI ≥ 40 kg/m² who undergo elective cesarean delivery.     

Effect of dexmedetomidine on the characteristics of bupivacaine in a caudal block in pediatrics

Background: Dexmedetomidine (DEX) is a highly selective α₂‐adrenoceptor agonist that has been used increasingly in children. However, the effect of caudal DEX has not been evaluated before in children. This prospective randomized double‐blinded study was designed to evaluate the analgesic efficacy of caudal DEX with bupivacaine in providing pain relief over a 24‐h period. Methods: Sixty children (ASA status I) aged 1–6 years undergoing unilateral inguinal hernia repair/orchidopexy were allocated randomly to two groups (n=30 each). Group B received a caudal injection of bupivacaine 2.5 mg/ml, 1 ml/kg; Group BD received the same dose of bupivacaine mixed with DEX 1 μg/kg during sevoflurane anesthesia. Processed electroencephalogram (bispectral index score), heart rate, blood pressure, pulse oximetry and end‐tidal sevoflurane were recorded every 5 min. The characteristics of emergence, objective pain score, sedation score and quality of sleep were recorded post‐operatively. Duration of analgesia and requirement for additional analgesics were noted. Results: The end‐tidal sevoflurane concentration and the incidence of agitation were significantly lower in the BD group (P<0.05). The duration of analgesia was significantly longer (P<0.001) and the total consumption of rescue analgesic was significantly lower in Group BD compared with Group B (P<0.01). There was no statistically significant difference in hemodynamics between both groups. However, group BD had better quality of sleep and a prolonged duration of sedation (P<0.05). Conclusion: Caudal DEX seems to be a promising adjunct to provide excellent analgesia without side effects over a 24‐h period. It has the advantage of keeping the patients calm for a prolonged time. Implications statement: Caudally administered DEX (1 μg/kg), combined with bupivacaine, was associated with an extended duration of post‐operative pain relief.     

Hämodynamische Reaktionen nach präoperativer hypervolämischer Hämodilution mit hyperton-hyperonkotischen Kolloiden bei Koronarbypassoperationen

ZusammenfassungFragestellung Die Möglichkeiten der Restriktion leicht diffusibler kristalloider Lösungen bei gleichzeitig erreichbarer hämodynamischer Stabilisierung lassen den Einsatz hypertoner Kolloide als Volumenersatzmittel bei herzchirurgischen Patienten geeignet erscheinen. Ziel der vorliegenden Untersuchung war es, erstmalig die hämodynamischen Effekte verschiedener hyperton-hyperonkotischer Kolloide bei koronarchirurgischen Patienten zu überprüfen.Methodik Es erhielten 43 Patienten mit normaler linksventrikulärer Ejektionsfraktion, die sich elektiv einer Koronarbypassoperation unterziehen mussten, nach Narkoseeinleitung, jedoch vor Operationsbeginn randomisiert folgende "Studienlösungen": 1.) 750 ml/m² KOF Natriumchloridlösung (0,9%iges NaCl; n=10, Kontrollgruppe, NACL); 2.) 250 ml/m² KOF Hydroxyethylstärke (10%ige HES, 200/0,5) und 400 ml/m² KOF 0,9%iges NaCl (n=9, HES); 3.) 250 ml/m² KOF 10%iges Dextran 40 und 300 ml/m² KOF 0,9%iges NaCl (n=8, DEX); 4.) 150 ml/m² KOF hypertones NaCl (7,2%ig), darin 10%ige HES, 200/0,5 (n=8, HYPER-HES) oder 5.) 150 ml/m² KOF hypertones NaCl (7,2%ig), darin 10%iges Dextran60 (n=8, HYPER-DEX). Hämodynamische Messungen erfolgten unmittelbar vor und 15 min nach Infusion der Studienlösungen sowie bis 60 min nach Beendigung der extrakorporalen Zirkulation (EKZ) in 10-minütigen Abständen. Flüssigkeitsbilanzen wurden intraoperativ, postoperativ bis 24 h nach Operationsende und für den Zeitraum während EKZ berechnet.Ergebnisse Nach Hämodilution kam es gegenüber dem Ausgangswert in allen Gruppen zu vergleichbaren Erhöhungen der rechts- bzw. linksventrikulären Füllungsdrücke. In der NACL-Gruppe zeigten sich leichte, in den 4 Gruppen mit kolloidaler Hämodilution hingegen deutliche Anstiege der Herz (CI)- und Schlagvolumenindices (SVI) sowie des Sauerstoffangebotes (DO₂) in der Präbypassphase. Diese Veränderungen erreichten in den Gruppen HYPER-HES und HYPER-DEX (CI: +38%, +54%; SVI: +42%, +40%; DO₂: +34%; +41%) statistische Signifikanz. Herzfrequenz und mittlerer arterieller Blutdruck zeigten keine wesentlichen Veränderungen nach Hämodilution. Der intraoperative Kristalloidbedarf war in den Gruppen HES und DEX deutlich, in den Gruppen HYPER-HES und HYPER-DEX (1.013±341 ml/m² KOF; 1.096±234 ml/m² KOF) signifikant gegenüber der Kontrollgruppe (NACL, 1.629±426 ml/m² KOF) erniedrigt. Die Serum-Natrium-Konzentration erreichte in den Gruppen HYPER-HES und HYPER-DEX maximal 150±3 mmol/l bzw. 149±4 mmol/l (Ausgangswerte: 141±3 mmol/l bzw. 141±1 mmol/l)Schlussfolgerungen Der präoperative Volumenersatz mit hyperonkotischen Kolloiden führt gegenüber einer präoperativen Volumensubstitution mit physiologischer Natriumchloridlösung zu verbesserten hämodynamischen Bedingungen während der Präbypassphase und zu einer Reduktion des intraoperativen Kristalloidbedarfs bei koronarchirurgischen Patienten mit normaler Ventrikelfunktion. Der volumensparende Effekt kann durch die Zubereitung hyperonkotischer Kolloide in hypertoner Natriumchloridlösung gesteigert werden, während die Auswahl des Kolloids (HES oder Dextran) von untergeordneter Bedeutung zu sein scheint.     

Improved postoperative analgesia with preoperative piroxicam

Purpose

Piroxicam like other Non-Steroidal Anti-Inflammatory drugs can be used to provide postoperative analgesia. With a half-life of 50 hr given preoperatively its’ analgesic effect should continue postoperatively. This study compared the effects of 20 mg piroxicam given at different times in the perioperative period on postoperative analgesic requirement.

Method

Following ethical committee approval and written informed consent, 60 ASA I and II patients presenting for inpatient gynaecological laparoscopic surgery were given either 20 mg piroxicam or a placebo po two hours preoperatively, immediately before induction of anaesthesia or one hour postoperatively in a randomised double bind manner.

Results

Postoperative Visual Analogue Pain Scores were lower on admission to the recovery ward in patients given piroxicam preoperatively (Group 1), than in the other two treatment groups (groups 2 and 3). Pain scores were 2.72 vs 4.25 vs 6.67 respectively (P < 0.001). Pain scores did not differ at any other times. Time to first analgesic request was greater in the group 1 than in the other two treatment groups; 141 (61) min vs 115 (147) in Group 2 and 30 (36) min in Group 3. Nine patients in Group 1 requested further analgesia compared with 15 in Group 2 and 16 in Group 3. There were no piroxicam-induced side-effects.

Conclusion

Piroxicam given two hours preoperatively reduced pain scores, time to first analgesia and postoperative analgesic requirements compared with administration prior to induction or one hour postoperatively.     

The effects of caudal or intravenous clonidine on postoperative analgesia produced by caudal levobupivacaine in children

Background: Clonidine is used increasingly in pediatric anesthesia practice to prolong the duration of action of caudal block with a local anesthetic agent. Which route of administration of clonidine is the most beneficial remains unknown. We compared the effects of caudal and intravenous clonidine on postoperative analgesia produced by caudal levobupivacaine. Methods: Sixty ASA I and II children, aged 2–8 undergoing inguinal hernia repair or orchidopexy surgery received standardized premedication with midazolam and general anesthesia. The children were randomized in a double‐blind fashion to three groups. Group L (n = 20) patients received 0.75 ml·kg^?1 of caudal 0.25% levobupivacaine and i.v. 5 ml saline, Group L‐Ccau (n = 20) patients received 0.75 ml·kg^?1 of caudal 0.25% levobupivacaine + 2 μg·kg^?1 clonidine and i.v. 5 ml saline, Group L‐Civ (n = 20) patients received 0.75 ml·kg^?1 of caudal 0.25% levobupivacaine and i.v. 2 μg·kg^?1 clonidine in 5 ml of saline. Mean arterial blood pressure, heart rate, peripheral oxygen saturation, and end‐tidal carbon dioxide values were recorded. Postoperative pain [Children and Infants Postoperative Pain Scale (CHIPPS) score], sedation (Ramsay Sedation Scale) and motor blockade (Modified Bromage Scale) were assessed at predetermined time points during the first 24 h after surgery. Results: Caudal clonidine significantly delayed the time to first rescue analgesic and fewer patients required rescue analgesia in the 24 h after surgery. No motor block was observed in any of the three groups on awakening or during the study period. In Group L‐Ccau, the CHIPPS score was lower than in Group L at all times through 240 min (P < 0.05), while the pain scores were lower in Group L‐Civ only at extubation and at 240 min (P < 0.05). Conclusions: Caudal clonidine prolongs the duration of analgesia produced by caudal levobupivacaine without causing significant side effects and this is because of a spinal mode of action.     

Patient-controlled epidural analgesia in labour: varying bolus dose and lockout interval

This double-blind prospective study was designed to determine the best dose variables for patient-controlled epidural analgesia (PCEA) and to compare bolus-only PCEA with continuous infusion epidural analgesia (CIEA) during the first stage of labour. Five groups of parturients self-administered 0.125% bupivacaine with 1:400,000 epinephrine and fentanyl 2.5 μg·ml^?1 using PCA pumps programmed as follows: Group A, 2 ml bolus/10 min lockout interval (LI); Group B, 3 ml bolus/15 min LI; Group C, 4 ml bolus/20 min LI; Group D, 6 ml bolus/30 min LI; Group E, 8 ml·hr^?1 continuous infusion. Hourly assessments included: VAS scores for pain and satisfaction, sensory and motor block, bupivacaine and fentanyl consumption. Blood samples were collected at birth for maternal and fetal fentanyl concentrations. Data from 68 patients showed no differences among groups in pain relief or maternal satisfaction. Most patients received excellent analgesia and those requiring extra epidural supplements were evenly distributed across groups. There was higher consumption of bupivacaine and fentanyl in Group E than in any of the other four groups: bupivacaine mg·hr^?1, mean (SD), 9.4 (2.7) in Group E vs 5.2 (1.7) in Groups A-D inclusive (P<0.0001); fentanyl μg·hr^?1, 19.6 (4.6) in Group E vs 12.6 (7.5) in Groups A-D inclusive (P<0.05). Motor block was minimal, whereas sensory levels were higher at the 3- and 4-hour assessments in Groups D and E than in all other groups (P<0.05). Plasma fentanyl concentrations were <0.5 ng·ml^?1 in all samples and no sequelae from fentanyl were observed, apart from mild pruritus. Bolus-only PCEA is a safe and effective alternative to CIEA during the first stage of labour irrespective of the initial dose variables selected.     

前锯肌平面阻滞与胸椎旁神经阻滞用于胸腔镜手术患者术后镇痛效果的比较

目的比较前锯肌平面阻滞与胸椎旁神经阻滞用于胸腔镜手术患者术后的镇痛效果。方法选择择期行胸腔镜手术患者60例,男38例,女22例,年龄18～65岁,BMI 18～25kg/m2,ASAⅠ或Ⅱ级,采用随机数字表法分为前锯肌平面阻滞组(S组)和胸椎旁阻滞组(T组),每组30例。两组患者均采用支气管插管静脉全身麻醉,术后采用PCIA。S组于麻醉诱导前行超声引导下前锯肌平面阻滞,T组则行超声引导下胸椎旁阻滞,两组均使用0.4%罗哌卡因30ml,阻滞完成后30min使用针刺法测定并记录感觉阻滞平面;记录阻滞操作时间、起效时间、持续时间;记录术后2、4、8、12、24、48h的静息和咳嗽VAS评分;记录首次按压镇痛泵时间、术后48h内镇痛泵有效按压次数、舒芬太尼使用总量和哌替啶补救性镇痛例数;记录阻滞相关并发症、镇痛不良反应发生情况。结果与T组比较,S组阻滞操作时间明显缩短,阻滞持续时间明显延长(P0.01);S组术后12h静息时和咳嗽时VAS评分明显降低(P0.01),S组PCIA首次按压时间明显延长,S组PCIA 48h内按压次数、舒芬太尼使用量明显减少(P0.01),两组气胸、恶心呕吐发生率差异无统计学意义。结论超声引导下前锯肌平面阻滞或胸椎旁阻滞均可为胸腔镜手术患者提供良好术后镇痛,但前锯肌平面阻滞较胸椎旁阻滞作用更持久、操作时间更短、并发症更少,且能有效减少患者术后对阿片类药物的需求量。     

低位直肠癌经括约肌间切除术后吻合口瘘对患者近远期肛门功能影响的临床分析

背景与目的：经括约肌间切除术(ISR)作为超低位直肠癌的极限保肛手术,已被证实可获得良好的肿瘤学根治效果。因其能最大程度地保留患者肛门,避免永久性肠造口,已逐渐成为了低位直肠癌保肛手术的重要选择之一。然而,ISR手术由于切除了部分或全部内括约肌,不可避免地会导致术后肛门控便功能的下降。吻合口瘘是ISR手术后最常见的并发症之一,可能对患者术后肛门功能产生不良影响。目前关于吻合口瘘对ISR术后患者的肛门功能的具体影响尚未有深入的研究。因此,本研究探讨吻合口瘘对ISR术后患者短期及长期肛门功能的影响。方法：回顾性收集中国人民解放军火箭军特色医学中心肛肠外科于2011年6月—2022年1月行ISR及预防性末端回肠造口术的236例患者临床及随访资料,比较发生与未发生吻合口瘘患者的一般临床资料、回肠造口还纳后6个月和2年Wexner失禁评分(WIS)与低位前切除综合征(LARS)评分以及肛门直肠测压各参数的差异。结果：236例患者中有41例(17.4%)发生吻合口瘘,23例(9.7%)最终未还纳回肠造口。与未发生吻合口瘘患者的一般临床资料比较结果显示,发生吻合口瘘患者BMI较高(27 kg/m     

Clonidine-mepivacaine mixture vs plain mepivacaine in paediatric surgery

In a double-blind study, 42 children, aged 1–10, undergoing general subumbilical surgery, were randomly allocated to two groups; they received, via caudal extradural, 1% mepivacaine 7 mg·kg^?1 and normal saline 1 ml (Group 1) and a mixture of 1% mepivacaine 7 mg·kg^?1 plus clonidine 2 μg·kg^?1 and normal saline up to 1 ml (Group 2) respectively. No significant difference was noticed in age, weight, duration of surgery and onset time of anaesthesia, blood pressure, heart rate and oxygen saturation. Mean duration of analgesia (evaluated with ‘Broadman objective pain scale') was 143 min for Group 1 and 218 min for Group 2 (P < 0.05); the time of sedation (evaluated with a sedation score) was statistically longer in Group 2 (172 min vs 89 min in Group 1). This longer sedation is due both to the longer analgesia and partially to a side effect of clonidine. In conclusion the addition of 2 μg·kg^?1 of clonidine to mepivacaine prolongs the duration of caudal analgesia in children.     

Epidural analgesia for labour and delivery: fentanyl or sufentanil?

Purpose

The highly lipid soluble opioids, fentanyl and sufentanil, are used in combination with local anaesthetics with/ without epinephrine to provide epidural analgesia during labour and delivery. Our aim was to determine whether either opioid was superior when used with low dose local anaesthetic.

Methods

In a double-blind study patients were randomized to two epidural infusion groups: Group I (n = 50) fentanyl 2 μg · ml^?1 with bupivacaine 0.015% and epinephrine 2 μg · ml^?1, Group II (n = 50) sufentanil 1 μg · ml^?1 with bupivacaine 0.015% and epinephrine 2 μg · ml^?1. Following a 20 ml bolus of the study solution an infusion was started at 10 ml · h^?1. To achieve analgesia patients could receive two boluses of 5 ml of the study solution and if analgesia was still inadequate, a further 5 ml bupivacaine 0.25% was used. Pain and overall satisfaction were assessed with a 10-point visual scale. Plasma samples obtained from the mother at the time the infusion was discontinued and from the umbilical cord vein at delivery were assayed to determine opioid concentration.

Results

Pain scores were greater for Group I than for Group II patients throughout the first and second stages of labour (P = 0.002). More patients in Group I (42%) requested a dose of bupivacaine 0.25% than in Group II (6%) (P < 0.0001) and the total dose of bupivacaine given to Group I patients was greater than that of Group II, 26.0 ± 22.0 mg vs. 13.4 ± 12.6 mg, P = 0.005. There were no differences with respect to first or second stage duration, incidence of side effects, infusion duration, outcome of labour or neonatal Apgar scores. There was no opioid accumulation in either maternal or foetal blood.

Conclusion

Epidural opioid infusion with very low dose bupivacaine (0.015%) achieved an overall high level of patient satisfaction in both groups without serious maternal or neonatal side effects. At the fentanyl-to-sufentanil ratio used here patients receiving sufentanil had lower pain scores and substantially fewer patients required bupivacaine rescue.     

Ultrasound guided single injection caudal epidural anesthesia of isobaric bupivacaine with/without dexamethasone for geriatric patients undergoing total hip replacement surgery

BackgroundDexamethasone has anti-inflammatory properties that can affect postoperative analgesia when added to caudal bupivacaine.MethodsSeventy-two geriatric patients scheduled for elective total hip replacement under ultrasound guided caudal anesthesia were randomized blindly into two groups: Group BD received caudal isobaric bupivacaine 0.25% (20 ml) and dexamethasone 8 mg (2 ml) and Group BS received caudal isobaric bupivacaine 0.25% (20 ml) and normal saline (2 ml). Postoperative analgesia was assessed by recording time to first rescue analgesia and the analgesic doses (paracetamol and meperidine hydrochloride) required during the first 24 h postoperatively as a primary outcome. Secondary outcomes were the time taken to the onset of sensory analgesia at T10, time to the onset of complete motor block, VAS pain score at rest and on movement at 1, 2, 4, 6, 8, 12 and 24 h, and postoperative adverse events.ResultsGroup BD had a significantly longer time to first rescue analgesia [402 (63) vs 213 (53)] min and significantly lower doses of paracetamol [3389 (728) vs 2833 (697)] mg meperidine hydrochloride [78 (30) vs 142 (28)] mg than Group BS. VAS scores were significantly lower in Group BD than Group BS both at rest and on movement respectively at 4, 6, 8, 12 and 24 h.ConclusionAdding dexamethasone with isobaric bupivacaine caudal anesthesia prolongs the duration of postoperative analgesia and decreased postoperative analgesic requirement in geriatric patients undergoing total hip replacement surgery in comparison isobaric bupivacaine alone.     

Postoperative patientcontrolled epidural analgesia with opioid bupivacaine mixtures

Purpose

To determine the efficacy and safety of patient-controlled epidural analgesia of morphine or fentanyl in combination with bupivacaine for postoperative pain relief.

Methods p]Forty ASA 1–11 patients scheduled for major abdominal surgery were studied. After insertion of a lumbar epidural catheter, patients were given a non-opioid general anaesthetic. After surgery patients complaining of pain, received a loading dose of 2 mg morphine (Group I) or 50 μg fentanyl (Group II). For continuing pain, 1 mg morphine in 4 ml bupivacaine 0.125% (0.25 mg·ml^?1 morphine and 1 mg·ml^?1 bupivacaine, Group I) or 20 μg fentanyl in 4 ml bupivacaine 0.125% (5 μg·ml^?1 fentanyl and 1 mg·ml^?1 bupivacaine Group II) were administered. Blood pressure, heart rate, respiratory rate and SpO₂ were monitored. Assessments of pain (VAS), nausea-vomiting, motor block, pruritus and sedation were recorded for 24 hr.

Results

No difference in pain or sedation was observed between groups, The 24 hr postoperative opioid consumption was 15.50 ± 7.53 mg morphine and 555.10 ± 183.85μg fentanyl. Total bupivacaine 0.125% consumption was 58.00 ± 30.14 ml in Group I and 101.05 ± 36.77 ml in Group II. One patient in Group II complained of motor weakness in one leg. The incidence of nausea (Group I 45%, Group II 10%P < 0.05) and pruritus (Group I 30%, Group II 5%P < 0.05) was less in patients receiving fentanyl. Conclusion: Both methods were effective in the prevention of pain but, because of fewer side effects, fentanyl may be preferable to morphine.