The advantages of hemodilution anesthesia for major liver resection in children

Antifibrinolytic agents for reducing blood loss in scoliosis surgery in children

BACKGROUND

This is an updated version of the original Cochrane review first published in 2008. Scoliosis surgery is often associated with substantial blood loss and potentially detrimental effects in children. Antifibrinolytic agents are often used to reduce perioperative blood loss. Clinical trials have evaluated their efficacy in children undergoing surgical correction of scoliosis, but no systematic review has been published. This review was first published in 2008 and was updated in 2016.

OBJECTIVES

To assess the efficacy and safety of aprotinin, tranexamic acid and aminocaproic acid in reducing blood loss and transfusion requirements in children undergoing surgery for correction of idiopathic or secondary scoliosis.

SEARCH METHODS

We ran the search for the previous review in June 2007. For this updated version, we searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 7), MEDLINE (1946 to August week 1 2015), Embase (1947 to 2015 week 38), Latin American Caribbean Health Sciences Literature (LILACS) (1982 to 14 August 2015), Database of Abstracts of Reviews of Effects (DARE; 2015, Issue 2) and reference lists of reviews and retrieved articles for randomized controlled trials in any language. We also checked the clinical trial registry at http://www.clinicaltrials.gov on 8 October 2015.

SELECTION CRITERIA

We included blinded and unblinded randomized controlled trials (RCTs) that evaluated the effects of antifibrinolytics on perioperative blood loss in children 18 years of age or younger and undergoing scoliosis surgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data. The primary outcome was total blood loss (intraoperative and postoperative combined). Secondary efficacy outcomes were the number of participants receiving blood transfusion (both autologous and allogeneic) or receiving allogeneic blood transfusion alone, and the total amount of blood transfused. Safety outcomes included the number of deaths, the number of participants reporting any adverse event or a serious adverse event, withdrawals due to adverse events and the number of participants experiencing a specific adverse event (i.e. renal insufficiency, hypersensitivity or thrombosis). We assessed methodological risk of bias for each included study and employed the GRADE approach to assess the overall quality of the evidence.

MAIN RESULTS

We included three new studies (201 participants) in this updated review, for a total of nine studies (455 participants). All but one study employed placebo as the control group intervention. For the primary outcome, antifibrinolytic drugs decreased the amount of perioperative blood loss by 427 mL (95% confidence interval (CI) 251 to 603 mL), for a reduction of over 20% versus placebo. We rated the quality of evidence for our primary outcome as low on the basis of unclear risk of bias for several domains in most studies and the small total number of participants.For secondary outcomes, fewer participants receiving antifibrinolytic drugs received transfusion (allogeneic or autologous) versus those receiving placebo (risk ratio (RR) 0.65, 95% CI 0.50 to 0.85, number needed to treat to prevent one additional harmful outcome (NNTp) 5; very low-quality evidence). Only two studies specifically evaluated the number of participants transfused with only allogeneic blood (risk difference (RD) -0.15, 95% CI -0.26 to -0.03, NNTp 7; very low-quality evidence). Antifibrinolytic drugs decreased the volume of blood transfused by 327 mL (95% CI -186 to -469 mL; low-quality evidence).No study reported deaths in active or control groups. Data were insufficient to allow performance of meta-analysis for any safety outcome. No studies adequately described their methods in assessing safety. The only adverse event of note occurred in one study, when three participants in the placebo group developed postoperative deep vein thrombosis.

AUTHORS' CONCLUSIONS

Since the last published version of this review (2008), we have found three new studies. Additional evidence shows that antifibrinolytics reduce the requirement for both autologous and allogeneic blood transfusion. Limited evidence of low to very low quality supports the use of antifibrinolytic drugs for reducing blood loss and decreasing the risk, and volume, of transfusion in children undergoing scoliosis surgery. Evidence is insufficient to support the use of a particular agent, although tranexamic acid may be preferred, given its widespread availability. The optimal dose regimen for any of these three agents has not been established. Although adverse events appear to occur infrequently, evidence is insufficient to confirm the safety of these agents, particularly for rare but potentially catastrophic events. No long-term safety data are available.

Circulating blood volumes: a review of measurement techniques and a meta-analysis in children

The accurate determination of circulating blood volume (CBV) in children has many clinical applications. The purposes of this article were to review currently available CBV measurement techniques and perform a meta-analysis using values from many small-scale studies that calculated CBV values for normal healthy children. A literature review demonstrated numerous methods by which to determine CBV. However, these methods necessitate repetitive blood sampling, require the introduction of foreign substances into the bloodstream, or address the uncertainty of substance distribution and clearance. Many small-scale studies have calculated CBV values for normal healthy children, and we performed a meta-analysis using these values. Age groups were defined, and within each group, means +/- 1 and 2 standard deviations were compared. A pooled estimate of mean blood volume and a 95% confidence interval was calculated after Q-statistics calculations indicated that the groups were homogeneous. Mean values showed agreement with typically accepted normal values. A large-scale study should be repeated when a gold standard for CBV measurements is developed.

[Perioperative management of Jehovah's Witness patients. Special consideration of religiously motivated refusal of allogeneic blood transfusion]

The religious organization of Jehovah's Witnesses numbers more than 7 million members worldwide, including 165,000 members in Germany. Although Jehovah's Witnesses strictly refuse the transfusion of allogeneic red blood cells, platelets and plasma, Jehovah's Witness patients may nevertheless benefit from modern therapeutic concepts including major surgical procedures without facing an excessive risk of death. The present review describes the perioperative management of surgical Jehovah's Witness patients aiming to prevent fatal anemia and coagulopathy. The cornerstones of this concept are 1) education of the patient about blood conservation techniques generally accepted by Jehovah's Witnesses, 2) preoperative optimization of the cardiopulmonary status and correction of preoperative anemia and coagulopathy, 3) perioperative collection of autologous blood, 4) minimization of perioperative blood loss and 5) utilization of the organism's natural anemia tolerance and its acute accentuation in the case of life-threatening anemia.

Antifibrinolytic agents for reducing blood loss in scoliosis surgery in children

BACKGROUND

Scoliosis surgery is often associated with substantial blood loss and potential detrimental effects in children. Antifibrinolytic agents are often used to reduce perioperative blood loss. Clinical trials have evaluated their effect in children undergoing surgical correction of scoliosis but no systematic review has been published. We performed a systematic review on the efficacy and safety of antifibrinolytic drugs in children undergoing scoliosis surgery.

OBJECTIVES

To assess the efficacy and safety of aprotinin, tranexamic acid and aminocaproic acid in reducing blood loss and transfusion requirements in children undergoing scoliosis surgery.

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library 2007, Issue 3), OVID MEDLINE (1950 to September 3rd 2007), LILACS (1992 to June 20th 2007) and EMBASE (1980 to July 23rd 2007). We also searched conference proceedings from 2003 to 2007 and the clinicaltrials.gov registry. No language restriction was applied.

SELECTION CRITERIA

We included blinded or unblinded randomized controlled trials that evaluated the effect of antifibrinolytics on perioperative blood loss in children that were 18 years of age or younger and undergoing scoliosis surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently performed the data extraction. Primary outcomes were mortality and number of patients transfused. Secondary outcomes were number of patients transfused with allogeneic blood, amount of total blood transfused, total blood loss and adverse events. To assess heterogeneity we used the I(2) test and for the quantitative analysis we used a fixed-effect model.

MAIN RESULTS

Six studies fulfilled the inclusion criteria. The total number of participants was 254, of whom 127 were allocated to placebo and 127 to antifibrinolytic drugs. Aprotinin, tranexamic acid and aminocaproic acid were evaluated in two studies each. All studies had placebo as the control group intervention. There were no deaths or any serious adverse events in any study, in either the active or the control group. The risk of being transfused was similar in patients receiving antifibrinolytic drugs or placebo. Antifibrinolytics drugs decreased the amount of blood transfused by 327 ml (95% CI -469.04 to -185.78) and the amount of blood loss by 427 ml (95% CI -602.51 to -250.56). There was no indication of publication bias, however, we cannot rule it out due to the small number of studies included.

AUTHORS' CONCLUSIONS

The effect of antifibrinolytic drugs on mortality could not be assessed. Antifibrinolytic drugs reduced blood loss and the amount of blood transfused in children undergoing scoliosis surgery; however, their effect on the number of children requiring blood transfusion remains unclear. Aprotinin, tranexamic acid and aminocaproic acid seem to be similarly effective.

[Tolerance to perioperative anemia. Mechanisms, influencing factors and limits]

Die zu erwartende Kostensteigerung im Transfusionswesen (steigender Fremdblutbedarf bei gleichzeitig rückläufiger Spendebereitschaft, Behandlungspflicht transfusionsassoziierter Folgeerkrankungen) erhöht den sozioökonomischen Stellenwert der Entwicklung institutionsspezifischer Transfusionsprogramme. Ein wesentlicher Bestandteil hierbei ist – neben einer schonenden Operationstechnik und der konsequenten perioperativen Anwendung fremdblutsparender Maßnahmen – die Ausschöpfung der natürlicherweise vorhandenen „Anämietoleranz“ des menschlichen Organismus (Toleranz größerer Blutverluste durch Verlust von „verdünntem“ Blut, Hinauszögern des Transfusionsbeginns bis nach chirurgischer Blutstillung, Gewinnung von autologem Blut). In der vorliegenden Übersicht werden die Mechanismen, Einflussgrößen und Grenzen dieser natürlichen Anämietoleranz für den Gesamtorganismus und für einzelne Organsysteme zusammengefasst und die sich daraus ergebende Indikation zur Erythrozytentransfusion abgeleitet. Unter kontrollierten Bedingungen (Narkose, strikte Aufrechterhaltung von Normovolämie, komplette Muskelrelaxierung, Hyperoxämie, Hypothermie) werden von kardiopulmonal gesunden Individuen kurzzeitig auch extreme Grade der Verdünnungsanämie [Hämoglobin- (Hb-)Wert <3 g/dl (<1,86 mmol/l)] ohne Transfusion toleriert. In der klinischen Routine bleibt diese Situation – nicht zuletzt in Ermangelung eines adäquaten Monitorings – jedoch auf spezielle Sonderfälle beschränkt (z. B. unerwartete große Blutverluste bei Zeugen Jehovahs, unerwarteter Engpass bei der Bereitstellung von Fremdblut). Die derzeit geltenden Empfehlungen verschiedener Expertenkommissionen decken sich dahingehend, dass perioperativ (1) bis zu einer Hb-Konzentration von 10 g/dl (6,21 mmol/l) auch bei alten Patienten und Patienten mit kardiopulmonalen Begleiterkrankungen eine Transfusion von Erythrozyten in der Regel nicht notwendig ist und (2) eine Transfusion bei jungen, gesunden Patienten ohne kardiopulmonale Vorerkrankungen (einschließlich Schwangeren und Kindern) erst ab einer Hb-Konzentration von <6 g/dl (<3,72 mmol/l) notwendig wird. Auch beatmete Intensivpatienten mit Polytrauma und Sepsis scheinen nicht von einer Transfusion auf Hb-Konzentration >9 g/dl (>5,59 mmol/l) zu profitieren. Bei massiven Blutverlusten und diffuser Blutungsneigung scheint ein Hb von 10 g/dl (6,21 mmol/l) zur Stabilisierung der Blutgerinnung beizutragen.

[Tolerance to perioperative anemia. Mechanisms, influencing factors and limits]

Die zu erwartende Kostensteigerung im Transfusionswesen erhöht den sozioökonomischen Stellenwert der Entwicklung institutionsspezifischer Transfusionsprogramme. Ein wesentlicher Bestandteil hierbei ist – neben einer schonenden Operationstechnik und der konsequenten perioperativen Anwendung fremdblutsparender Maßnahmen – die Ausschöpfung der natürlichen „Anämietoleranz“ des menschlichen Organismus. Im vorliegenden Beitrag werden die Mechanismen, Einflussgrößen und Grenzen dieser Anämietoleranz für den Gesamtorganismus und für einzelne Organsysteme zusammengefasst und die sich daraus ergebende Indikation zur Erythrozytentransfusion abgeleitet. Die derzeit geltenden Empfehlungen decken sich dahingehend, dass bis zu einer Hämoglobinkonzentration von 10 g/dl (6,21 mmol/l) auch bei alten Patienten oder kardiopulmonalen Begleiterkrankungen eine perioperative Transfusion in der Regel nicht notwendig ist und bei jungen, gesunden Patienten ohne kardiopulmonale Vorerkrankungen (einschließlich Schwangeren und Kindern) erst ab <6 g/dl (<3,72 mmol/l) notwendig wird. Auch beatmete Intensivpatienten mit Polytrauma und Sepsis scheinen nicht von einer Transfusion auf eine Hämoglobinkonzentration >9 g/dl (>5,59 mmol/l) zu profitieren. Bei massiven Blutverlusten und diffuser Blutungsneigung scheint ein Wert von 10 g/dl (6,21 mmol/l) zur Stabilisierung der Blutgerinnung beizutragen.

Blood Conservation in Pediatric Anesthesia

This review focuses on perioperative blood conservation techniques and the role of transfusion triggers and algorithms, preoperative autologous donation, acute normovolemic hemodilution, intraoperative blood salvage, deliberate hypotension, and preoperative recombinant human erythropoietin in avoiding allogeneic blood transfusion in pediatric patients.

Erythropoietin therapy and acute preoperative normovolaemic haemodilution in infants undergoing craniosynostosis surgery

BACKGROUND

A retrospective study was performed to evaluate whether pretreatment with erythropoietin and iron combined with acute preoperative normovolaemic haemodilution (APNH) could decrease homologous blood transfusion in craniosynostosis (CS) surgery. A treated group was compared with a historical group of infants who underwent surgery with no pretreatment.

METHODS

The charts of 25 healthy infants who underwent CS surgery were reviewed. Nine of them underwent surgery with no treatment beforehand. Sixteen infants were given erythropoietin at a dosage of 300 U.kg -1 two times per week and iron (elemental iron 10 mg.kg-1.day-1) for 3 weeks before surgery. On the day of surgery APNH was performed after induction of general anaesthesia; a precalculated amount of autologous blood was withdrawn and replaced by hydroxyethyl starch 6%.

RESULTS

Eleven of the 16 infants of the study group received only autologous blood. Five of 16 received homologous blood transfusion vs seven of nine infants in the control group.

CONCLUSIONS

APNH combined with erythropoietin was effective in reducing homologous blood requirements during CS surgery. Further studies are necessary on a larger scale to assess the role of this technique in avoiding homologous blood transfusion and to evaluate how infants can benefit from this combined approach.

Blood support for pediatric surgery

Increasingly complicated surgeries are being performed on neonatal and pediatric patients. Provision of a safe and adequate blood supply is essential for the success of many of these surgeries. Depending on the clinical situation, autologous and/or allogeneic blood may be used. However, in all cases, every attempt should be made to minimize the number of donor exposures to reduce the risk of transfusion transmitted infections. Transfusion of neonatal and pediatric patients requires additional considerations too, such as the risk of graft vs host disease, cytomegalovirus infection, the effects of various preservative anticoagulant solutions, electrolyte levels during blood storage, and wheather or not leukoreduced components are indicated.

Perioperative autologous blood donation in children

Autologous blood donation in children has become a standard of care. Children have to live with the life-time complications associated with allogeneic blood including the transmission of known and unknown pathogens, and the impact of alloimmunization on future blood transfusions, organ transplants and pregnancies. Donor reaction, allogeneic exposure and utilization rates in pediatric preoperative autologous donation (PAD) programs are as good if not better than reported in adult literature. Children are very resilient when undergoing extreme isovolemic hemodilution (IHD). PAD, IHD and intraoperative blood recovery appear to be useful components of a pediatric blood conservation program. Prospective, randomized studies addressing the specific needs of children are required to properly define their perioperative role.

Acute isovolemic hemodilution during major hepatic resection--an initial report: does it safely reduce the blood transfusion requirement?

Surgical resection remains the mainstay of treatment for patients with hepatic tumors, despite the associated morbidity including the need for blood transfusion. Acute isovolemic hemodilution (AIH) has been shown to decrease the transfusion requirement for cardiac, urologic, and orthopedic procedures. However, the reported experience with AIH during hepatic resections is limited. Seven patients underwent major hepatic resection from July 1992 to June 1994 with standard AIH. Their clinical parameters were compared with those of nine matched control patients during the same time period. AIH and control patients had similar preoperative laboratory values (hematocrit, bilirubin, and coagulation studies), extent of liver resection, and pathologic diagnoses. Mean tumor diameters were larger in the AIH group (9.3 cm vs. 5.8 cm). Most important, patients managed with AIH required homologous blood transfusions significantly less often than the control group (14% vs. 67%; P=0.05). Furthermore, if they did receive transfusions, AIH patients needed fewer units of red cells (0.1+/-0.1 units vs. 1.7+/-0.6 units). There was no morbidity associated with AIH. AIH can be safely performed in patients undergoing major hepatic resection for malignancy. AIH appears to reduce the number of patients requiring homologous blood transfusion as well as the number of units transfused per patient. This technique warrants further study in a larger prospective, randomized trial.

Effects of hemodilution during controlled hypotension of hepatic, renal, and pancreatic function in humans

STUDY OBJECTIVE

To evaluate the effects of hemodilution during controlled hypotension on, the hepatic renal, and pancreatic function in the clinical setting.

DESIGN

Randomized, prospective study.

SETTING

Inpatient surgery at Rosai Hospital.

PATIENTS

20 ASN status I and II patients scheduled for total hip arthroplasty.

INTERVENTIONS

Hemodilution was carried out after induction of anesthesia, in which drawn blood was replaced with dextran solution to achieve final hematocrit (Hct) of 31% Group A = mild hemodilution group, N = 10) or 23% (Group B = moderate hemodilution group, N = 10). In both groups, controlled hypotension was induced with prostaglandin in (PGE1) to maintain mean arterial blood pressure at 55 mm Hg for 80 minutes.

MEASUREMENTS AND MAIN RESULTS

Measurements included arterial ketone body ratio AKBR, aceto-acetate/3-hydroxybutyrate) for hepatic cellular function, pancreatic phospholipase A2 (P-PLA2) for pancreatic cellular function, and urine N-acetyl-beta-D-glucosaminidase (NAG index) for cellular function of the renal tubule. These indices were measured before hemodilution, after hemodilution, 80 minutes after starting hypotension, 60 minutes after recovery of normotension, and on the first postoperative day. Neither AKBR nor P-PLA2 showed a significant change throughout the time course of the study in either group. Urine-NAG index showed a significant increase in moderate hemodilution group at 60 minutes after recovery of normotension (+ 136%) and on the first postoperative lay (+ 149%) compared with prehemodilution value, whereas it showed no significant change in the mild hemodilution group. Blood urea nitrogen and serum creatinine measured postoperatively were within normal range.

CONCLUSIONS

PGE1 induced hypotension combined with moderate hemodilution using dextran, such as 23% of Net value maintains hepatic and pancreatic function but causes damage to the renal tubular cells.

Systemic haemodynamics and oxygenation during haemodilution in children

Transfusion of homologous blood should be avoided when possible, and one technique that diminishes perioperative requirement for donor blood is haemodilution. In children its effects on systemic haemodynamics and systemic oxygenation have not been reported. Six children aged 4-12 yr were anaesthetised for major surgery and blood was withdrawn to reduce packed cell volume to 25%. Cardiac index increased from 3.1 (SD 0.5) L min-1 m-2 at baseline to 4.4 (0.5) L min-1 m-2 at the end of surgery, when packed cell volume was 16 (1)%; this change, compensating for the decline in oxygen carrying capacity, was associated with a fall in systemic vascular resistance and a rise in stroke volume. Oxygen extraction from haemoglobin rose from 0.22 (0.05) to 0.33 (0.06). Perioperative blood loss was 40% of circulating blood volume; however, owing to reinfusion of autologous blood (and use of a cell saver in three patients), the haemoglobin one day after operation was only 19% lower than preoperatively (9.9 [1.5] vs 12.5 [2.5] g/dL). In this study, children seemed at least as able as adults to compensate for the effects of haemodilution, which allowed major surgery without transfusion of homologous blood.

Autologous blood transfusion in the pediatric patient

The use of autologous blood has been encouraged by blood banks and transfusion services for the past 10 years, mainly because of public concern over the safety of blood. The virtues include reduced likelihood of reactions to transfused blood and reduction or elimination of the risk of alloimmunization and transfusion transmitted diseases such as hepatitis C and the human immunodeficiency virus. The pediatric patient population has been largely excluded from published series on autologous blood usage. In this article, the literature on the use of autologous blood in pediatric patients is reviewed, and some considerations for collecting autologous blood from smaller patients are addressed, including the volume of blood to collect from smaller patients. Based on the experience reported in the literature, patients as young as 6 years of age may be candidates for autologous blood donation before a scheduled surgical procedure. Other methods to provide autologous blood for pediatric patients are discussed, including intraoperative hemodilution and intraoperative and postoperative blood salvage. By considering all the potential options available to pediatric patients, the likelihood of requiring transfusion of allogeneic blood can be reduced, along with the associated risks.

Predeposited autologous blood transfusion for surgery in infants and children

Homologous blood transfusions have associated infectious and immunological risks. Since 1989 the authors have conducted predeposited autologous blood transfusions (PABT) for infants and children in whom transfusions were expected to be required during an elective operation. Autologous blood was deposited in 13 patients ranging in age from 9 months to 10 years (median, 21 months) with weight from 7.3 kg to 33.6 kg (median, 10.5 kg). They included eight patients with Hirschsprung's disease, three patients with benign tumors, and two others. The volume of predeposition was calculated to maintain the patients' hematocrit at 30% after collection. Blood was deposited once or twice, 1 to 2 weeks before the operation. The actual volume of predeposited blood was 19.1 +/- 2.4 mL/kg in infants with Hirschsprung's disease, 21.8 +/- 10.0 mL/kg in children with Hirschsprung's disease, and 12.6 +/- 2.2 mL/kg in children with other diseases. Nine patients were operated on using only PABT, 2 patients required homologous blood transfusions in addition to PABT, and 2 patients did not require any blood transfusions. No complications occurred as a result of PABT except preoperative anemia. PABT is a safe and effective means of procuring blood for intraoperative transfusions in infants and children undergoing major elective general pediatric surgical procedures.

Intraoperative hemodilution and autologous platelet rich plasma collection: two techniques for collecting fresh autologous blood

Intraoperative hemodilution (IH) and autologous platelet rich plasma (APRP) collection are two techniques used to obtain autologous blood in the operating room. They have been used to reduce allogeneic blood exposure in patients undergoing both cardiac and non-cardiac surgery. Both components have the advantage of providing fresh blood not subject to the storage lesion. Whole blood (IH) or platelet rich plasma is removed from the patient as anesthesia is induced and replaced with acellular fluid. The blood is transfused back after bypass or major bleeding has ceased. Although used commonly, the data supporting the use of either technique are controversial. Methodologic problems which have confounded studies evaluating their utility include: poorly defined transfusion criteria, concommitant use of other blood conservation techniques (i.e. cell salvage, pharmacologic agents, hypothermia, controlled hypotension) and changing transfusion practices with greater tolerance of normovolemic anemia. Randomized controlled studies with well defined up to date transfusion criteria are needed to identify patients likely to benefit from these techniques.

Oxygen consumption and cardiovascular function in children during profound intraoperative normovolemic hemodilution

The clinically acceptable limit of acute normovolemic, normothermic hemodilution, a standard procedure in scoliosis surgery, is not yet well defined. Eight ASA class I patients undergoing idiopathic scoliosis correction were administered a standard anesthetic with 100% oxygen and controlled ventilation. Hemodilution was accomplished by exchanging whole blood for 5% albumin in 0.9% saline. Blood gases, acid-base status, and circulatory variables were recorded prior to and after hemodilution, and every 30 min throughout surgery. The impact of hemodilution was judged by mixed venous oxygen saturation which was maintained at > or = 60%, while intravascular volume was maintained with the 5% albumin solution. Reinfusion of the autologous blood was completed by the end of surgery. In the eight controlled cases in which normovolemic hemodilution was studied, hemoglobin levels decreased from 10.0 +/- 1.6 g/dL to 3.0 +/- 0.8 g/dL. Mixed venous oxygen saturation decreased from 90.8% +/- 5.4% to 72.3% +/- 7.8%. Oxygen extraction ratio increased from 17.3% +/- 6.2% to 44.4% +/- 5.9%. Oxygen delivery decreased from 532.1 +/- 138.1 mL.min-1.m-2 to 260.2 +/- 57.1 mL.min-1.m-2, while global oxygen consumption did not decrease and plasma lactate did not appreciably increase. Central venous pressure increased and peripheral resistance decreased during hemodilution. Cardiac index increased, heart rate remained essentially constant, and left ventricular stroke work index did not decrease significantly. No patients suffered clinically adverse outcomes. Global oxygen transport and myocardial work can be maintained at extreme normovolemic anemia. Our evidence suggests that stages of normovolemic hemodilution more severe than previously reported may be clinically acceptable for young, healthy patients during normocarbic anesthesia.

Difficulties in demonstrating efficacy of blood substitutes

Currently, the fear of infectious disease transmission by allogenic blood transfusions has spurred interest in developing a blood substitute FDA approval requires that a sponsor demonstrate that the substitute is effective. The challenge in designing efficacy studies in man is proving that the substitute offers significant advantages over conventional therapies for acute blood loss. This task is complicated by the oxygen reserve and the response to hemodilution following treatment of acute blood loss in man. Paradoxically, the technique that relies on these protective physiologies-isovolemic perioperative hemodilution-many offer the best experimental model to establish efficacy of a blood substitute in man.

Transfusion and surgery

In this survey of transfusion in surgery, we have attempted to provide the surgeon with an understanding of the problems associated with homologous transfusion and a practical knowledge of treatment strategies and alternatives designed to reduce homologous blood exposure. Such a review cannot be encyclopedic. Our hope is that it will serve the reader as a stimulus to examine his or her transfusion practices and as a guide for future self-learning.

Primary hepatic tumours in children: a 26-year review

Twenty-one children were admitted to a single paediatric institution between 1964-1990 with histologically proven primary liver tumours. The diagnosis was hepatoblastoma (HBL) in 15 patients, hepatocellular carcinoma (HCA) in 2, rhabdomyosarcoma (RMS) in 2, non-Hodgkin's lymphoma (NHL) in 1, and haemangioendothelioma (HE) in 1. The common presenting clinical features were anaemia, abdominal mass, and abdominal pain. Serum alpha-foetoprotein was useful in establishing a diagnosis in HBL and in monitoring disease activity. Computed tomographic (CT) scan, ultrasound, and angiography were useful preoperative investigations for assessing site and resectability of tumour. There were no survivors in patients with malignant hepatic tumours (n = 10) who had surgery alone prior to 1981. Of 7 patients with HBL diagnosed after 1981 who had adequate surgical resection and chemotherapy, 5(72%) are currently alive and disease free between 15 months and 8 years from diagnosis. We conclude that adequate surgical resection and adjuvant chemotherapy can improve disease free survival for children with HBL. Optimal treatment has yet to be devised for other malignant hepatic tumours.

Resection, including transplantation, for hepatoblastoma and hepatocellular carcinoma: impact on survival

Long-term survival in children with primary hepatic malignancies can not be expected without complete tumor resection. In the last ten years we have treated 21 children with hepatocellular carcinoma (HCC) and 21 children with hepatoblastoma (HEP), with tumor extirpation our surgical goal. Operative treatment included partial hepatectomy ([PH] 20), either primary (10) or delayed (following chemotherapy) (10), total hepatectomy and orthotopic liver transplantation ([OLT] 13), or upper abdominal exenteration and multiple organ transplantation (2). Two patients had both PH and subsequent total hepatectomy and OLT. Overall survival was 48% (20/42), with 9 patients dying of progressive disease prior to removal of their tumor. HEP patient survival was 67% (14/21), including 2 of 6 who underwent primary PH, 7 of 8 who had delayed PH, and 5 of 6 who underwent OLT. Survival for the children with HCC was 29% (6/21), including 1 of 4 after primary PH, 1 of 2 following delayed PH, 3 of 7 following OLT, and 1 of 2 after exenteration and multiple organ transplantation. Preoperative chemotherapy facilitated removal of 10 initially unresectable tumors (8 HEP, 2 HCC) at a second-look procedure. Total hepatectomy and OLT markedly improved survival in patients with disease unresectable by standard methods. Partial hepatectomy, either primary or delayed, should be attempted in all children with hepatic malignancies. Total hepatectomy and OLT appears to be a viable adjunct in the treatment of childhood malignancies, and should be used for otherwise unresectable tumors as part of a carefully planned protocol.

Autologous hemodonation in the corrective surgery of craniostenosis

Homologous transfusions are mandatory in most surgical procedures for correcting craniofacial malformations in infancy. A program of preoperative and intraoperative auto-hemodonation was developed and carried out in eleven infants. Although homologous transfusion could have been avoided in only 7 patients, we think that further experiences and minor corrections of our program may improve these results.

Pediatric hepatic surgery

Tumors of the liver are uncommon in children. It is imperative that surgeons caring for these patients have a knowledge of the likely diagnosis, proper radiographic evaluation, and appropriate selection and extent of surgical therapy. Of the benign lesions, infantile hemangioendothelioma often is best treated nonoperatively, whereas mesenchymal hamartoma and teratoma should be resected. All malignant lesions must be completely excised to cure the patient, but some may be converted from unresectable tumors to resectable ones by preoperative chemotherapy. Major hepatic resection is one of the most formidable procedures in the surgery of children. Careful preparation, attention to technical detail, and precise postoperative management of the critically ill child are prerequisites for success. For a recent review of the extrahepatic biliary tract problems of infants and children, the reader is referred to the article by Stolar and Altman in Surgical Clinics of North America, Volume 65, October 1985.

Extensive tumor resection under deep hypothermia and circulatory arrest

The risk of fatal hemorrhage may limit the completeness of resection in hepatic malignancies and in vascular extensions of Wilms' tumors. We have used Ein's technique of deep hypothermia (average 17 degrees C) with cardiac arrest (average 39 minutes) and exsanguination in performing five hepatic and two intravenous Wilms' tumor resections. The initial hepatic resection takes less than 15 minutes to perform in a bloodless field and the specimen is immediately examined by frozen section for determination of adequacy of margin. Additional resection is easily performed. Of four trisegmentectomies and one left lobectomy, two required additional resections. Mattress sutures were used to control hemorrhage during recirculation. One patient died from bleeding and cardiac decompensation and another from recurrence of tumor. The Wilms' tumors extended from the iliac vein into the right atrium in one child and from the right renal vein to the right atrium with extensions into the hepatic and lumbar veins in another. After nephrectomy, the atria and inferior vena cava were opened and the tumor extracted under direct vision. Both patients are well.