Central Venous Blood Pressure Research Articles

Determinants of arterial and central venous blood pressure variation in ventilated critically ill children

Ventilation-induced arterial pressure variation predicts volume responsiveness in adults. Several factors are known to influence the interpretability of these variations. We analysed ventilation-induced variations in critically ill children with reference to ventilatory and circulatory parameters. We prospectively included 20 paediatric patients. Variation of systolic pressure (SPV), pulse pressure (PPV) and central venous pressure (CVP) were assessed during pressure-controlled ventilation with inspiratory pressures (P(insp)) of 20 and 28 cmH(2)O. Blood gases were analysed and echocardiography was performed. SPV, PPV and CVP variation significantly increased with elevated P(insp) (p < 0.001, p = 0.008 and p = 0.003). Baseline CVP and shortening fraction were significant negative predictors of PPV and SPV. This preliminary study identified P(insp) as a determinant of SPV, PPV and CVP variation in children. Further independent determinants of SPV and PPV were baseline CVP and ventricular performance, both of which must be considered when interpreting pressure variations.

Effect of passive pneumoperitoneum on oesophageal pressure, cardiovascular parameters and blood gas analysis in horses

Standing surgical procedures are being employed to an ever-greater extent in horses. Pneumoperitoneum during abdominal surgery might adversely affect the work of breathing. To determine whether development of pneumoperitoneum during abdominal surgery adversely influences the work of breathing. Eight healthy mature horses were equipped with carotid artery and thoracic vena cava catheters and an intraluminal manometry system. The following measurements were obtained before and at +5, +10, +15 and +30 min following establishment of pneumoperitoneum by paralumbar puncture using an 8 gauge needle: vital signs, oesophageal pressure, gastric pressure, arterial and central venous blood pressures, and arterial and mixed venous blood gas analyses. Significant changes in oesophageal pressure, central venous pressure and results of arterial and mixed venous blood gas analysis were not detected. Arterial diastolic and mean pressures and rectal temperature increased slightly (P ≤ 0.05). Passive pneumoperitoneum did not adversely affect breathing mechanics or haemodynamic variables under experimental conditions. Changes in arterial pressure could have occurred as a response to the passive pneumoperitoneum or be related to handling stress. Subtle variations in rectal temperature were not clinically relevant and likely resulted from stress associated with restraint. It is unlikely that mature horses will develop signs of respiratory difficulty as a result of the development of passive pneumoperitoneum during standing laparoscopy.

Respiratory and cardiovascular effects of doxapram and theophylline for the treatment of asphyxia in neonatal calves

Respiratory stimulants are widely used in asphyxic neonatal calves despite a lack of data about their effectiveness and indications of possible side effects. The effect of doxapram and theophylline on respiratory, cardiovascular, and acid-base variables was investigated in 10 healthy neonatal calves (Bos Taurus). A venous, a peripheral arterial, and a pulmonary arterial catheter were placed, and central venous, pulmonary, and systemic blood pressures and cardiac output were measured using thermodilution technique. Doxapram, but not theophylline, led to an immediate increase in respiratory rate (P ≤ 0.01). The arterial pCO 2 decreased to 27.1 ± 4.7 mm Hg within 30 sec after doxapram administration and to 46.3 ± 5.8 mm Hg within 120 min after theophylline administration (P < 0.0001). The systolic pulmonary pressure increased from 70 ± 8 mm Hg (mean ± SD) to 93 ± 19 mm Hg within 30 sec after doxapram, but decreased after theophylline. The pulmonary vascular resistance also increased after doxapram and decreased after theophylline (P < 0.01). Doxapram had a more pronounced and faster effect on respiratory rate and elimination of CO 2 than theophylline. Doxapram, but not theophylline, is indicated for treatment of postnatal asphyxia in calves, but there are potential cardiovascular side effects.

Effects of airway pressure release ventilation on blood pressure and urine output in children.

Increased intrathoracic pressures during airway pressure release ventilation (APRV) may compromise systemic venous return resulting in decreased cardiac output and renal perfusion. We sought to study the short-term effect of APRV on blood pressure (BP) and urine output (UO) in children with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). Retrospective cohort study. All patients with ALI/ARDS who were admitted to our Pediatric Intensive Care Unit (PICU) between 1/00 and 06/04, and who were ventilated with APRV (for at least 12 hr) for worsening oxygenation while on conventional ventilation (CV). Medical records were reviewed for patients' demographics, Pediatric Risk of Mortality (PRISM III) score, admitting diagnosis, ventilator settings, gas exchange data, heart rate (HR), central venous pressure (CVP), blood pressure (BP), UO, and use of other therapies [sedatives, pressors, inotropes, and intravenous fluid (IVF)]. Eleven patients met our inclusion and exclusion criteria with a mean age of 6.2 +/- 4.8 years (range: 1-15 years), a weight of 35.5 +/- 29.5 kg (range: 12-90 kg), and a PRISM score of 18.4 +/- 9.6 (range: 2-36). Within 10 hrs of APRV, patients' mean airway pressure (Paw) increased from 16.1 +/- 6.6 to 21.1 +/- 5.5 cm of H(2)O (P = 0.04). Despite a higher Paw there were no differences in HR, CVP, BP, UO, IVF and use of other therapies while on CV or APRV (P > 0.10). In children with ALI/ARDS, despite a higher Paw, APRV does not affect BP or UO.

Treatment of a patient with shock complicating severe falciparum malaria: a case report

IntroductionMalaria is a potentially life-threatening disease, especially when complicated by a septic shock. When patients present in such a critical condition, the currently available literature allows a dilemma to develop as to which the correct treatment strategy is concerning fluid resuscitation.Case presentationA 55-year-old Caucasian man was admitted to the intensive care unit with the clinical picture of severe malaria, brought by a Plasmodium falciparum infection. On admission, the patient was confused, had high fever up to 40°C, and his blood analysis revealed a severe thrombocytopenia, a parasitemia of 25.5%, and biochemical features indicative of severe malaria. The patient received quinine and underwent two automated red cell exchanges by use of a centrifuge-driven cell separator. Two days after admission, the patient developed a septic shock. He received an "early-goal" treatment, according to the surviving sepsis campaign guidelines, which propose fluid resuscitation. The existing recommendations concerning the treatment of severe malaria that favour a restrictive fluid administration were disregarded. Fluid therapy was guided by regular measurements of the central venous pressure, blood pressure and monitoring of the hemodynamic status. The patient survived the shock and the subsequent multiorgan failure, which required mechanical ventilation and dialysis. After 12 days in the intensive care unit and an additional three weeks of hospitalization, the patient was discharged to rehabilitation.ConclusionThe authors believe that in patients with severe malaria complicated by septic shock, the treatment of sepsis and septic shock should be the one of first priority.

Treatment of a patient with shock complicating severe falciparum malaria: a case report.

Malaria is a potentially life-threatening disease, especially when complicated by a septic shock. When patients present in such a critical condition, the currently available literature allows a dilemma to develop as to which the correct treatment strategy is concerning fluid resuscitation. A 55-year-old Caucasian man was admitted to the intensive care unit with the clinical picture of severe malaria, brought by a Plasmodium falciparum infection. On admission, the patient was confused, had high fever up to 40 degrees C, and his blood analysis revealed a severe thrombocytopenia, a parasitemia of 25.5%, and biochemical features indicative of severe malaria. The patient received quinine and underwent two automated red cell exchanges by use of a centrifuge-driven cell separator. Two days after admission, the patient developed a septic shock. He received an "early-goal" treatment, according to the surviving sepsis campaign guidelines, which propose fluid resuscitation. The existing recommendations concerning the treatment of severe malaria that favour a restrictive fluid administration were disregarded. Fluid therapy was guided by regular measurements of the central venous pressure, blood pressure and monitoring of the hemodynamic status. The patient survived the shock and the subsequent multiorgan failure, which required mechanical ventilation and dialysis. After 12 days in the intensive care unit and an additional three weeks of hospitalization, the patient was discharged to rehabilitation. The authors believe that in patients with severe malaria complicated by septic shock, the treatment of sepsis and septic shock should be the one of first priority.

Circulatory limits to oxygen supply during an acute temperature increase in the Chinook salmon (Oncorhynchus tshawytscha)

This study was undertaken to provide a comprehensive set of data relevant to disclosing the physiological effects and possible oxygen transport limitations in the Chinook salmon (Oncorhynchus tshawytscha) during an acute temperature change. Fish were instrumented with a blood flow probe around the ventral aorta and catheters in the dorsal aorta and sinus venosus. Water temperature was progressively increased from 13 degrees C in steps of 4 degrees C up to 25 degrees C. Cardiac output increased from 29 to 56 ml.min(-1).kg(-1) between 13 and 25 degrees C through an increase in heart rate (58 to 105 beats/min). Systemic vascular resistance was reduced, causing a stable dorsal aortic blood pressure, yet central venous blood pressure increased significantly at 25 degrees C. Oxygen consumption rate increased from 3.4 to 8.7 mg.min(-1).kg(-1) during the temperature increase, although there were signs of anaerobic respiration at 25 degrees C in the form of increased blood lactate and decreased pH. Arterial oxygen partial pressure was maintained during the heat stress, although venous oxygen partial pressure (Pv(O(2))) and venous oxygen content were significantly reduced. Cardiac arrhythmias were prominent in three of the largest fish (>4 kg) at 25 degrees C. Given the switch to anaerobic metabolism and the observation of cardiac arrhythmias at 25 degrees C, we propose that the cascade of venous oxygen depletion results in a threshold value for Pv(O(2)) of around 1 kPa. At this point, the oxygen supply to systemic and cardiac tissues is compromised, such that the oxygen-deprived and acidotic myocardium becomes arrhythmic, and blood perfusion through the gills and to the tissues becomes compromised.

Enforced exercise, but not acute temperature elevation, decreases venous capacitance in the stenothermal Antarctic fish Pagothenia borchgrevinki

The venous haemodynamic response to enforced exercise and acute temperature increase was examined in the Antarctic fish Pagothenia borchgrevinki (borch) to enable comparisons with the existing literature for temperate species, and investigate if the unusual cardiovascular response to temperature changes previously observed in the borch can be linked to an inability to regulate the venous vasculature. Routine central venous blood pressure (P (cv)) was 0.08 kPa and the mean circulatory filling pressure (P (mcf); an index of venous capacitance) was 0.14 kPa. Acute warming from 0 to 2.5 and 5 degrees C increased heart rate (f (H)), while dorsal aortic blood pressure (P (da)) decreased. P (mcf) did not change, while P (cv) decreased significantly at 5 degrees C. This contrasts with the venoconstriction previously observed in rainbow trout in response to increased temperature. Exercise resulted in small increases in P (mcf) and P (cv), a response that was abolished by alpha-adrenoceptor blockade. This study demonstrates that the heart of P. borchgrevinki normally operates at positive filling pressures (i.e. P (cv)) and that venous capacitance can be actively regulated by an alpha-adrenergic mechanism. The lack of decrease in venous capacitance during warming may suggest that a small increase in venous tone is offset by a passive temperature-mediated increase in compliance.

Pericardial effusions after heart surgery. Incidence and clinical sequelae

The frequency and clinical outcome of pericardial effusions was investigated in 104 patients following open-heart surgery. A pre- and post-operative echocardiogram was made in all cases. Pericardial effusions were present in 26%, significantly more occurring after bypass surgery (37%) than after valve replacement (15%). In 4 out of 5 cases the effusion had no haemodynamic effect and in no instance was a repeat thoracotomy necessary. A significantly higher incidence of reduced exercise tolerance, increased heart rate, atrial fibrillation and a radiologically demonstrable increase in heart size of more than 10 mm, were indicative of the presence of pericardial effusions. In contrast, central venous pressure and blood pressure were no higher than in patients without pericardial effusion. Complication-free pericardial effusions thus occur frequently after cardiac surgery. A reliable diagnosis is only possible by means of echocardiography. It remains to be shown whether the long-term clinical progress is affected.

Effects of gastric distension on the cardiovascular system in rainbow trout (Oncorhynchus mykiss)

When animals feed, blood flow to the gastrointestinal tract increases to ensure an adequate oxygen supply to the gastrointestinal tissue and an effective absorption of nutrients. In mammals, this increase depends on the chemical properties of the food, as well as, to some extent, on the mechanical distension of the stomach wall. By using an inflatable nitrile balloon positioned in the stomach, we investigated the cardiovascular responses to mechanical stretch of the stomach wall in rainbow trout (Oncorhynchus mykiss). Distension with a volume equivalent to a meal of 2% of the body mass increased dorsal aortic blood pressure by up to 29%, and central venous blood pressure increased transiently nearly fivefold. The increase in arterial pressure was mediated by an increased vascular resistance of both the systemic and the intestinal circulation. Cardiac output, heart rate, and stroke volume (SV) did not change, and only transient changes in gut blood flow were observed. The increase in arterial pressure was abolished by the alpha-adrenergic antagonist prazosin, indicating an active adrenergic vasoconstriction, whereas the venous pressor response could be the consequence of a passive increase in intraperitoneal pressure. Our results show that mechanical distension of the stomach causes an instantaneous increase in general vascular resistance, which may facilitate a redistribution of blood to the gastrointestinal tract when chemical stimuli from a meal induce vasodilation in the gut circulation. The normal postprandial increase in gut blood flow in teleosts is, therefore, most likely partly dependent on mechanical stimuli, as well as on chemical stimuli.

The Immediate and Sustained Effects of Volume Challenge on Regional Blood Flows in Pigs

The postoperative assessment of volume status is not straightforward because of concomitant changes in intravascular volume and vascular tone. Hypovolemia and blood flow redistribution may compromise the perfusion of the intraabdominal organs. We investigated the effects of a volume challenge in different intra- and extraabdominal vascular beds. Twelve pigs were studied 6 h after major intraabdominal surgery under general anesthesia when clinically normovolemic. Volume challenges consisted of 200 mL rapidly infused 6% hydroxyethyl starch. Systemic (continuous thermodilution) and regional (ultrasound Doppler) flows in carotid, renal, celiac trunk, hepatic, and superior mesenteric arteries and the portal vein were continuously measured. The acute and sustained effects of the challenge were compared with baseline. Volume challenge produced a sustained increase of 22% +/- 15% in cardiac output (P < 0.001). Blood flow increased by 10% +/- 9% in the renal artery, by 22% +/- 15% in the carotid artery, by 26% +/- 15% in the superior mesenteric artery, and by 31% +/- 20% in the portal vein (all P < 0.001). Blood flow increases in the celiac trunk (8% +/- 13%) and the hepatic artery (7% +/- 19%) were not significant. Increases in regional blood flow occurred early and were sustained. Mean arterial and central venous blood pressures increased early and decreased later (all P < 0.05). A volume challenge in clinically euvolemic postoperative animals was associated with a sustained increase in blood flow to all vascular beds, although the increase in the celiac trunk and the hepatic artery was very modest and did not reach statistical significance. Whether improved postoperative organ perfusion is accompanied by a lower complication rate should be evaluated in further studies.

Volume Replacement Therapy during Major Orthopedic Surgery Using Voluven® (Hydroxyethyl Starch 130/0.4) or Hetastarch

The purpose of this study was to test the equivalence of efficacy and compare the safety of the 6% hydroxyethyl starches (HES) Voluven (HES 130/0.4; Fresenius Kabi, Bad Homburg, Germany) and hetastarch (HES 670/0.75 in saline) for intravascular volume replacement therapy during major orthopedic surgery. In a prospective, controlled, randomized, double-blind, multicenter trial of patients undergoing major orthopedic surgery, 49 patients were treated with HES 130/0.4 and 51 patients were treated with hetastarch. Infusion of colloids was guided by central venous and arterial blood pressures. The primary efficacy endpoint was the volume of colloid solution infused; the primary safety endpoints were calculated total erythrocyte loss, the nadir factor VIII activity, and the nadir von Willebrand factor concentration within 2 h of completion of surgery. The total volume of colloid solution required for intraoperative volume replacement did not differ between HES 130/0.4 and hetastarch (1,613+/-778 [SD] ml for HES 130/0.4 and 1,584+/-958 ml for hetastarch). The nadir factor VIII activity within 2 h of the end of surgery was lower for hetastarch than for HES 130/0.4 (P=0.0499); for those who received greater than 1,000 ml colloid, the nadir factor VIII activity and von Willebrand factor concentration within 2 h of end of surgery were lower for hetastarch than for HES 130/0.4 (P=0.0487 and P=0.008, respectively). Voluven (HES 130/0.4) and hetastarch are equally efficacious plasma volume substitutes; however, HES 130/0.4 has a lesser effect on coagulation.

Cardiovascular changes under normoxic and hypoxic conditions in the air-breathing teleostSynbranchus marmoratus: importance of the venous system

Synbranchus marmoratus is a facultative air-breathing fish, which uses its buccal cavity as well as its gills for air-breathing. S. marmoratus shows a very pronounced tachycardia when it surfaces to air-breathe. An elevation of heart rate decreases cardiac filling time and therefore may cause a decline in stroke volume (V(S)), but this can be compensated for by an increase in venous tone to maintain stroke volume. Thus, the study on S. marmoratus was undertaken to investigate how stroke volume and venous function are affected during air-breathing. To this end we measured cardiac output (Q), heart rate (f(H)), central venous blood pressure (P(CV)), mean circulatory filling pressure (MCFP), and dorsal aortic blood pressures (P(DA)) in S. marmoratus. Measurements were performed in aerated water (P(O2)>130 mmHg), when the fish alternated between gill ventilation and prolonged periods of apnoeas, as well as during hypoxia (P(O2)<or=50 mmHg), when the fish changed from gill ventilation to air-breathing. Q increased significantly during gill ventilation compared to apnoea in aerated water through a significant increase in both f(H) and V(S). P(CV) and MCFP also increased significantly. During hypoxia, when the animals surface to ventilate air, we found a marked rise in f(H), P(CV), MCFP, Q and V(S), whereas P(DA) decreased significantly. Simultaneous increases in P(CV) and MCFP in aerated, as well as in hypoxic water, suggests that the venous system plays an important regulatory role for cardiac filling and V(S) in this species. In addition, we investigated adrenergic regulation of the venous system through bolus infusions of adrenergic agonists (adrenaline, phenylephrine and isoproterenol; 2 microg kg(-1)). Adrenaline and phenylephrine caused a marked rise in P(CV) and MCFP, whereas isoproterenol led to a marked decrease in P(CV), and tended to decrease MCFP. Thus, it is evident that stimulation of both alpha- and beta-adrenoreceptors affects venous tone in S. marmoratus.

Adrenergic control of venous capacitance during moderate hypoxia in the rainbow trout (Oncorhynchus mykiss): role of neural and circulating catecholamines

Central venous blood pressure (P(ven)) increases in response to hypoxia in rainbow trout (Oncorhynchus mykiss), but details on the control mechanisms of the venous vasculature during hypoxia have not been studied in fish. Basic cardiovascular variables including P(ven), dorsal aortic blood pressure, cardiac output, and heart rate were monitored in vivo during normoxia and moderate hypoxia (P(W)O(2) = approximately 9 kPa), where P(W)O(2) is water oxygen partial pressure. Venous capacitance curves for normoxia and hypoxia were constructed at 80-100, 90-110, and 100-120% of total blood volume by transiently (8 s) occluding the ventral aorta and measure P(ven) during circulatory arrest to estimate the mean circulatory filling pressure (MCFP). This allowed for estimates of hypoxia-induced changes in unstressed blood volume (USBV) and venous compliance. MCFP increased due to a decreased USBV at all blood volumes during hypoxia. These venous responses were blocked by alpha-adrenoceptor blockade with prazosin (1 mg/kg body mass). MCFP still increased during hypoxia after pretreatment with the adrenergic nerve-blocking agent bretylium (10 mg/kg body mass), but the decrease in USBV only persisted at 80-100% blood volume, whereas vascular capacitance decreased significantly at 90-110% blood volume. In all treatments, hypoxia typically reduced heart rate while cardiac output was maintained through a compensatory increase in stroke volume. Despite the markedly reduced response in venous capacitance after adrenergic blockade, P(ven) always increased in response to hypoxia. This study reveals that venous capacitance in rainbow trout is actively modulated in response to hypoxia by an alpha-adrenergic mechanism with both humoral and neural components.

Venous responses during exercise in rainbow trout, Oncorhynchus mykiss: α-adrenergic control and the antihypotensive function of the renin–angiotensin system

The role of the α-adrenergic system in the control of cardiac preload (central venous blood pressure; P ven) and venous capacitance during exercise was investigated in rainbow trout ( Oncorhynchus mykiss). In addition, the antihypotensive effect of the renin–angiotesin system (RAS) was investigated during exercise after α-adrenoceptor blockade. Fish were subjected to a 20-min exercise challenge at 0.66 body lengths s −1 (BL s −1) while P ven, dorsal aortic blood pressure ( P da) and relative cardiac output ( Q) was recorded continuously. Heart rate ( f H), cardiac stroke volume (SV) and total systemic resistance ( R sys) were derived from these variables. The mean circulatory filling pressure (MCFP) was measured at rest and at the end of the exercise challenge, to investigate potential exercise-mediated changes in venous capacitance. The protocol was repeated after α-adrenoceptor blockade with prazosin (1 mg kg −1 M b) and again after additional blockade of angiotensin converting enzyme (ACE) with enalapril (1 mg kg −1 M b). In untreated fish, exercise was associated with a rapid (within approx. 1–2 min) and sustained increase in Q and P ven associated with a significant increase in MCFP (0.17 ± 0.02 kPa at rest to 0.27 ± 0.02 kPa at the end of exercise). Prazosin treatment did not block the exercise-mediated increase in MCFP (0.25 ± 0.04 kPa to 0.33 ± 0.04 kPa at the end of exercise), but delayed the other cardiovascular responses to swimming such that Q and P ven did not increase significantly until around 10–13 min of exercise, suggesting that an endogenous humoral control mechanism had been activated. Subsequent enalapril treatment revealed that these delayed responses were in fact due to activation of the RAS, because resting P da and R sys were decreased further and essentially all cardiovascular changes during exercise were abolished. This study shows that the α-adrenergic system normally plays an important role in the control of venous function during exercise in rainbow trout. It is also the first study to suggest that the RAS may be an important modulator of venous pressure and capacitance in fish.

This Month in Anesthesiology

This Month in Anesthesiology

Avaliação das pressões venosa e arterial em cães submetidos a diferentes tipos de hipotensão

Estabeleceram-se a pressão venosa periférica (PVP), a pressão venosa central (PVC), a pressão arterial invasiva (PAI) e a pressão arterial não invasiva (PANI) em cães após diferentes eventos de hipotensão. Foram utilizados 15 cães adultos, distribuídos aleatoriamente em três grupos (G) com cinco animais cada, submetidos aos seguintes eventos hipotensores: GI - cloridrato de xilazina a 2%, GII - choque hipovolêmico agudo e GIII - veneno da serpente Bothrops moojeni. Os animais, avaliados durante 30 minutos após o início do evento hipotensor, foram tratados com cloridrato de ioimbina (GI), amido hidroxietílico a 6% (GII) e cetoprofeno (GIII) e reavaliados por mais 30 minutos. Somente os animais do GII apresentaram redução da PVP após o evento hipotensor e aumento, 25 minutos após tratamento. Os cães dos grupos II e III mostraram redução da PVC após o evento hipotensor, e somente os animais do GII exibiram discreto aumento cinco minutos imediatamente após o tratamento. Houve diminuição da PAI e PANI nos dos grupos II e III após o evento hipotensor, com recuperação gradativa imediata, após o tratamento, somente da PAI.

The effect of moderate hypovolemia on cardiopulmonary function in dogs

AbstractObjective: To collate canine cardiopulmonary measurements from previously published and unpublished studies in instrumented, unsedated, normovolemic and moderately hypovolemic dogs.Design: Collation of data obtained from original investigations in our research laboratory.Setting: Research laboratory, School of Veterinary Medicine.Subjects: Sixty‐eight dogs.Interventions: Subjects were percutaneously instrumented with an arterial catheter and a thermodilution cardiac output catheter. A femoral artery catheter was percutaneously placed for blood removal.Measurements and main results: Body weight, arterial and mixed‐venous pH and blood gases, arterial, pulmonary arterial, pulmonary artery occlusion, and central venous blood pressure, cardiac output, and core body temperature were measured. Body surface area, bicarbonate concentration, standard base excess, cardiac index (CI), stroke volume, systemic and pulmonary vascular resistance, left and right ventricular work and stroke work indices, left and right rate‐pressure product, alveolar PO2, alveolar–arterial PO2 gradient, arterial and mixed‐venous and pulmonary capillary oxygen content, oxygen delivery, oxygen consumption, oxygen extraction, venous admixture, arterial and venous blood carbon dioxide content, arterial–venous carbon dioxide gradient, carbon dioxide production were calculated.In 68 dogs, hypovolemia sufficient to decrease mean arterial blood pressure (ABPm) to an average of 62 mmHg, was associated with the following changes: arterial partial pressure of carbon dioxide (PaCO2) decreased from 40.0 to 32.9 mmHg; arterial base deficit (BDa) increased from −2.2 to −6.3 mEq/L; lactate increased from 0.85 to 10.7 mm/L, and arterial pH (pHa) did not change. Arterial partial pressure of oxygen (PaO2) increased from 100.5 to 108.3 mmHg while mixed‐venous PO2 (PmvO2) decreased from 49.1 to 34.1 mmHg. Arterial and mixed‐venous oxygen content (CaO2 and CmvO2) decreased from 17.5 to 16.5 and 13.8 to 9.6 mL/dL, respectively. The alveolar–arterial PO2 gradient (A‐a PO2) increased from 5.5 to 8.9 mmHg while venous admixture decreased from 2.9% to 1.4%. The ABPm decreased from 100 to 62 mmHg; pulmonary arterial pressure (PAPm) decreased from 13.6 to 6.4 mmHg; and pulmonary arterial occlusion pressure (PAOP) decreased from 4.9 to 0.1 mmHg. CI decreased from 4.31 to 2.02 L/min/m2. Systemic and pulmonary vascular resistance (SVRI and PVRI) increased from 1962 to 2753 and 189 to 269 dyn s/cm5, respectively. Oxygen delivery (DO2) decreased from 787 to 340 mL/min/m2 while oxygen consumption (VO2) decreased from 172 to 141 mL/min/m2. Oxygen extraction increased from 20.9% to 42.3%.Conclusions: Moderate hypovolemia caused CI and oxygen delivery to decrease to 47% and 42% of baseline. Oxygen extraction, however, doubled and, therefore, oxygen consumption decreased only to 82% of baseline.

Transfusion requirements during cadaveric and living donor pediatric liver transplantation

Surgical techniques that have been used during liver transplantation (LT) together with patient's coagulation profile and institutional practices are reported to have an effect on transfusion requirements. The aim of this study is to evaluate the transfusion requirement in both cadaveric (CDLT, n = 22) and living donor (LDLT, n = 24) pediatric LT performed in our institution. Balanced general anesthesia was used for all patients. Transfusion requirements were met to maintain a hemoglobin concentration of 8-10 g/dL, platelet level >50 x 10(3)/mL, prothrombin time <20 s and hemodynamic course with observing heart rate, arterial and central venous blood pressures and hourly urine output. Blood loss was replaced by using whole blood. Both groups' perioperative total blood and fresh-frozen plasma (FFP) volumes transfused, fluid requirements and hemodynamic courses, standard coagulation profile and metabolic variables determined in time periods of operations, patients' preoperative characteristics, operative features and postoperative events were compared. The mean transfusion requirements were 37.1 +/- 33.4 and 74.8 +/- 90.8 mL/kg of whole blood (p = 0.059) and 34.5 +/- 24.9 and 51.5 +/- 59.7 mL/kg of FFP for CDLT and LDLT, respectively (p = 0.519). The mean ages and mean body weights of the CDLT patients were higher than LDLT patients (9.7 +/- 5.3 vs. 6.6 +/- 4.4 yr, p = 0.015 and 32.4 +/- 17.7 vs. 21.0 +/- 14.8 kg, p = 0.032, respectively) while the mean operation time (493 +/- 135 vs. 323 +/- 93 min, p = 0.0001) and PELD score (13.1 +/- 11.2 vs. 20.1 +/- 11.8, p = 0.036) were higher for LDLT. In the entire population, multiple regression analysis showed that age, body weight and operation time have a significant combined effect on blood consumption (r2= 0.29, p = 0.003) meanwhile operation time was found to be an effective single variable (p = 0.002). None of the single or combined variables was found to have a significant effect on FFP consumption (r2= 0.17, p = 0.63) and crystalloid use (r2= 0.19, p = 0.11). Hemodynamic courses of both groups were similar. The incidences of metabolic acidosis and hypothermia during the anhepatic periods were higher in the CDLT group (p < 0.05). However, transfusion requirement in the ICU were higher in LDLT group [6.9 +/- 2.2 (n = 6) vs. 18.6 +/- 19 (n = 11) mL/kg, p < 0.05] after LT. As a result of this study in a pediatric patient population, no statistical significance was found in whole blood transfusion and FFP requirements between CDLT and LDLT. Duration of the operation was the primary factor effecting transfusion volume showing the importance of continued small volume losses during uncomplicated LT in this small sized patient population. Transfusion need for pediatric LT should be individualized for each patient based on the intraoperative conditions including surgical and patient features.

Effect of semi-invasive cardiovascular monitoring on the perioperative outcome of kidney or lung xenotransplantation in cynomolgus monkeys

Summary >Background: Cynomolgus monkeys (Macaca fascicularis) are one of the predominant primate models in experimental transplantation. Particularly in xenotransplantation experiments, they can be subjected to profound cardiovascular instability by surgical trauma, volume shifts and inflammatory mediator release. Meticulous perioperative management including deliberate intraoperative monitoring is therefore required. Methods: 26 porcine kidneys (group A) and 3 single lung lobes (group B), obtained from unmodified pigs or from pigs transgenic for human complement regulators, were transplanted into 29 cynomolgus monkeys. In group A 1 (n = 11) the monkeys were monitored intraoperatively by ECG, non-invasive arterial, and central venous blood pressure (standard cardiovascular monitoring, SCVM). In group A 2 (n = 15) measurements of cardiac output (CO), intrathoracic blood volume and extravascular lung water (extended cardiovascular monitoring, XCVM) were added to the intraoperative monitoring regime. XCVM plus continuous pulse contour CO was used in the 3 monkeys undergoing porcine single lung xenotransplantation. Results: In group A 2 significantly more animals had initial graft function if compared to group A 1 . 40% of the monkeys of group A 2 but 73% of group A 1 died within the first postoperative week. Group A 2 displayed a trend towards greater overall survival rates, but this difference did not reach statistical significance (p = 0,07). In group B stable lung xenograft reperfusion was achieved in all 3 recipients despite recurrent phases of severe cardiovascular instability. Two lung recipients could be weaned from the ventilator, and 1 monkey survived more than 24 hours postoperatively. Conclusions: The application of XCVM in small primates undergoing kidney xenotransplantation led to significantly better early postoperative results and longer survival times. In single lung xenotransplantation XCVM plus continuous pulse contour CO showed to be indispensable for the therapeutic management of the profound cardiovascular instabilities observed. Our data indicate that comprehensive anaesthesiologic monitoring can contribute substantially to the advancement of experimental organ transplantation in small monkeys.