J. R. Kambam

Extracorporeal membrane oxygenation in children after repair of congenital cardiac lesions

BACKGROUND The purpose of this study was to review our experience in the early application of extracorporeal membrane oxygenation (ECMO) in patients requiring mechanical assistance after cardiac surgical procedures. METHODS The hospital records of all children requiring ECMO after cardiac operation were retrospectively reviewed, and an analysis of variables affecting survival was performed. RESULTS Fifty pediatric patients between May 1997 and October 2000 required ECMO for cardiopulmonary support after cardiac operation. Patients ranged in age from 1 day to 11 years (median age, 40 days). Forty-eight patients underwent repair of congenital cardiac lesions and 2 were included after receiving a heart transplant. Twenty-two children could not be weaned from cardiopulmonary bypass and were placed on ECMO in the operating room for circulatory support. Of the 28 children who required ECMO in the intensive care unit, 10 had ECMO instituted after cardiopulmonary arrest (mean cardiopulmonary resuscitation time 42 minutes; range, 5 to 110 minutes). In infants with single-ventricle physiology, survival to discharge was 61% (11 of 18 patients) as compared with 43% (14 of 32 patients) in those with biventricular physiology. Thirty of the 50 patients (60%) were successfully weaned from ECMO, of which 25 (83%) were discharged home. Overall survival to discharge in the entire cohort was 50%. Extracorporeal membrane oxygenation support greater than 72 hours was a grave prognostic indicator. Overall survival in this group was 36% (9 of 25 patients) compared with 56% (14 of 25 patients) in those with ECMO support less than 72 hours (p < 0.05). Univariate analysis revealed the presence of renal failure, extended periods of circulatory support, and a prolonged period of cardiopulmonary resuscitation as risk factors for mortality. The presence of shunt-dependent flow, operative procedure, and institution of ECMO in the intensive care unit did not alter survival. CONCLUSIONS Extracorporeal membrane oxygenation provides effective support for postoperative cardiac and pulmonary failure refractory to medical management. Early institution of ECMO may decrease the incidence of cardiac arrest and end-organ damage, thus increasing survival in these critically ill patients.

Immunoreactive substance P is decreased in saliva of patients with chronic back pain syndromes

Substance P, a neuropeptide associated with pain perception, is widely distributed in the central nervous system and is decreased in the cerebrospinal fluid of chronic pain patients as compared with that of healthy human volunteers. In this study, we have demonstrated the presence of immunoreactive substance P in saliva and further, that both saliva and plasma levels of immunoreactive substance P are lower in patients with chronic low back pain than in healthy human volunteers. To our knowledge, this is the first time that substance P has been identified in human saliva. These findings, together with the noninvasive nature of saliva collection, suggest that substance P in saliva may be useful as an alternative neurochemical correlate of chronic low back pain when collection of cerebrospinal fluid and plasma samples for substance P analysis is unacceptable or inappropriate.

Pre-treatment with somatostatin in the anaesthetic management of a patient with carcinoid syndrome

Carcinoid syndrome produces flushing, bronchoconstriction and gastrointestinal hypermotility secondary to serotonin, histamine, bradykinin and prostaglandin release. A variety of drugs, foods and anaesthetic agents may provoke this syndrome. Under anaesthesia, the flushing produced may be associated with acute hypotension and cardiovascular collapse; this phenomenon is called a carcinoid crisis. Recently, somatostatin analogue has been used successfully to treat intraoperative carcinoid crisis. In this report, we present a 66-year-old lady with carcinoid syndrome who was pre-treated with 50 μg somatostatin analogue IV and IM prior to surgical manipulation. The anaesthetic course was relatively uneventful and the patient did well postoperatively.RésuméLe syndrome carcinoïde produit du “flushing,” bronchoconstriction et hypermotilité gastro-intestinale secondaire à la libération de sérotonine, histamine, bradykinine et de prostaglandin. Une variété de médicaments, produits alimentaires et agents anesthésiques peut provoquer ce syndrome. Sous anesthésie, le “flushing” peut être associé à une hypotension aiguë et un collapsus cardiovasculaire; ce phénomène est connu comme étant la crise carcinoïde. Récemment un analogue de la somastotatine a été utilisé avec succès pour traiter cette crise carcinoïde en période peropératoire. On présente ici le cas ďune femme de 66 ans atteinte ďun syndrome carcinoïde et qui fut pré-traitée avec 50 mg ďun analogue à la somastotatine par voie intraveineuse et intramusculaire avant la manipulation chirurgicale. La conduite anesthésique et les suites postopératoires furent sans complication.

Intravenous Chloroprocaine Attenuates Hemodynamic Changes Associated with Direct Laryngoscopy and Tracheal Intubation

We compared the effects of an IV administration of chloroprocaine and lidocaine on circulatory responses associated with endotracheal intubation. Thirty patients were randomly allocated to receive normal saline (placebo), lidocaine (1.5 mg/kg), or preservative-free chloroprocaine (4.5 mg/kg) 45 s before endotracheal intubation. Blood pressures and heart rate and rhythm were recorded before laryngoscopy and at 0.5, 1, 1.5, 2, 3, and 5 min after intubation. Blood samples were analyzed for catecholamine and chloroprocaine concentrations. Chloroprocaine reduced increases in blood pressure in response to intubation when compared with patients receiving normal saline and lidocaine. Systolic blood pressures at 0.5 and 1 min after intubation were significantly lower in the chloroprocaine group when compared with both the control and lidocaine groups (P < 0.05). Diastolic and mean blood pressures were significantly lower in the chloroprocaine group at all time points until 5 min after intubation (P < 0.05). Chloroprocaine and, to a lesser degree, lidocaine, produced marked attenuation of intubation-induced increases in plasma concentration of epinephrine and norepinephrine. Plasma concentrations of norepinephrine were significantly smaller in the chloroprocaine group at 0.5, 1, and 1.5 min, and plasma concentrations of epinephrine were significantly smaller at 0.5 after intubation when compared with control and lidocaine groups (P < 0.05). Measurable concentrations of chloroprocaine were recorded in plasma samples for 2 min after its administration. No adverse chloroprocaine effects (i.e., circulatory disturbances, venous irritation) were detected. The IV administration of chloroprocaine effectively blunted cardiovascular response produced by laryngoscopy and endotracheal intubation, and this effect was more pronounced when compared with IV lidocaine. Implications The IV administration of chloroprocaine effectively blunted cardiovascular response produced by laryngoscopy and endotracheal intubation, and this effect was more pronounced when compared with IV lidocaine.

In vitro effects of fluoride and bromide on pseudocholinesterase and acetylcholinesterase activities

The in vitroeffects of two metabolites ofinhalational anaesthetics, fluoride and bromide, on pseudocholinesterase (PCHE) and acetylcholinesterase (ACHE) activities in the blood samples of seven healthy patients were studied. The PCHE and ACHE activities were determined by kinetic spectrophotometric methods. Fluoride at the levels achieved with clinical concentrations of enjlurane and sevoflurane (25–75 μM · L−1) inhibited PCHE activity by 28–65 per cent (P < 0.01) and ACHE activity by less than five per cent (P > 0.05). Bromide at the levels achieved with clinical concentrations ofinhalational anaesthetics had no significant effect on either PCHE or ACHE activity. We recommend caution when succinylcholine and/or ester type local anaesthetics are used in the immediate postoperative period following enflurane or sevoflurane anaesthesia. We also recommend that blood drawing for PCHE activity be delayed at least until 24 hr following enflurane or sevoflurane anaesthesia.RésuméLes effets in vitrode deux métabolites anesthésiques d’inhalation, le fluorure el le bromure sur les activités de la pseudocho-linesterase (PCHE) el l’acetylcholinesterase (ACHE) out été étudié sur les échantillons sanguins de sept patients en bonne sante. Les activités de la PCHE et l’ACHE out été déterminées par spectrophotométrie. Les niveaitx de fluorure atteints avec des concentrations d’enjlurane et de sevoflurane à des concen-trations utilisees en clinique (25–75 μM · L−1) out inhibé l’activite de la PCHE de 28–65 pour cent (P < 0.0l) et l’activité de l’ACHE de moins de cinq pour cent (P > 0.05). Les niveaux de bromure atteints aux concentrations anesthesiques utilisees en clinique n’ont eu aucun effet significatif sur les activites de la PCHE ou de l’ACHE. On recommande la précaution lors de l’utilisation de la succinylcholine etlou les anesthésiques locaux dans la période post-opératoire immédiate après l’anesthésique à l’enflurane ou le sevoflurane. On recommande aussi que la prise d’échantillon sanguin pour l’activite de la PCHE soit retardée d’au moins 24 heures après l’anesthésie à l’enflurane ou la sevoflurane.

Alcohol pretreatment alters the metabolic pattern and accelerates cocaine metabolism in pigs

We investigated whether alcohol pretreatment would affect the disposition and metabolic pattern of intravenously (i.v.) administered cocaine in pigs. Six pigs (Group A) received alcohol (1 g/kg/day) and six pigs (control; Group D) received an equal volume of isocaloric dextrose 44% in water for 10 days via an intragastric tube. On day 11, arterial samples were taken for five hours following an intravenous administration of cocaine hydrochloride (4 mg/kg). Plasma concentrations of cocaine and its major metabolites were analyzed by HPLC method. Significant decrease in plasma half-life (10 +/- 1.2 vs. 18.7 +/- 1.4 min), and significant increases in apparent volume of distribution (73 +/- 6 vs. 51 +/- 31) and clearance (5.37 +/- 0.6 vs. 1.82 +/- 0.1 l/min) were seen in alcohol pretreated pigs as compared with control pigs (P < 0.05). Significant increases in plasma concentrations of benzoylecgonine (P < 0.05), and insignificant differences in ecgonine methyl ester and norcocaine levels were seen between the two groups. Neither ecgonine nor cocaethylene was detected in the blood samples. Our data show that alcohol administration for ten days accelerated the elimination of i.v. administered cocaine and altered its metabolic pattern in pigs.

Tobacco Smoking by Pregnant Women Disturbances in Metabolism of Branched Chain Amino Acids and Fetal Growtha

Pregnancy alone lowered the plasma AA concentrations of ileu, leu, and val when compared to their concentrations in nonpregnant nonsmokers. Plasma concentrations of val, ileu, and leu were significantly higher in pregnant smokers than in pregnant nonsmokers. Therefore, the utilization of BCAA was more reduced in pregnant smokers than that which could be predicted from plasma AA concentrations of nonpregnant nonsmokers.

Rapid determination of chloroprocaine and its major metabolite, 2-chloroaminobenzoic acid, in plasma by high-performance liquid chromatography

A sensitive and specific high-performance liquid chromatographic method for determination of the 2-chloroprocaine, local anesthetic of ester type, and its major metabolite 2-chloroaminobenzoic acid, has been developed and validated. A single-step extraction procedure is employed followed by high-performance liquid chromatographic separation using reversed-phase column and analysis using variable length UV detection. Lidocaine was used as internal standard for 2-chloroprocaine measurement and p-aminobenzoic acid was used as internal standard for 2-chloroaminobenzoic acid analysis. The analysis of spiked plasma demonstrated good accuracy and precision of the method with limit of detection 0.1 microgram/ml for 2-chloroprocaine and 0.5 microgram/ml for 2-chloroaminobenzoic acid. The method has been used for pharmacokinetic studies in laboratory animals.

Substance P level is increased in the cholesterol induced anaphylactoid reaction in the pig

The role of substance P (SP) in cholesterol-induced anaphylactoid reaction was investigated in 13 Landrace pigs. Pigs were anesthetized with sodium thiopental and ventilation was controlled with 70% nitrous oxide in oxygen. A Swan-Ganz catheter and a carotid arterial line were placed to monitor the hemodynamic data. Group 1 pigs (control group,n=5) each received 20 ml of intravenous (IV) colloid infusion solution (Haemaccel) and group 2 pigs (cholesterol group,n=8) each received an IV injection of pure cholesterol emulsion (12 mg/kg) in 20 ml of Haemaccel. Blood samples for SP and histamine (H) levels were taken just before and for 10 min following the placebo, Haemaccel, and cholesterol injections. Urine samples were also collected just before and at 60 min following the injections for methyl histamine (MH) levels. Group 2 pigs (cholesterol) developed an anaphylactoid reaction as indicated by marked and significant hemodynamic changes. None of the group 1 (placebo) pigs developed an anaphylactoid reaction. Significant increases in blood SP and H levels (P<0.05), and urine MH levels (P<0.05) were seen in cholesterol-treated pigs (group 2), whereas no significant changes were seen in control pigs (group 1). Our results suggest that SP is involved in the cholesterol-induced anaphylactoid reaction in pigs.

Pseudocholinesterase Activity in Human Cerebrospinal Fluid

Pseudocholinesterase (PCHE) activity and dibucaine numbers (DN) in the cerebrospinal fluid (CSF) and plasma of 10 ASA physical status 1 and 2 patients were measured using a kinetic method. CSF had a mean PCHE activity of 0.018 ± 0.013 unit/ml with a DN of 59 ± 4. Whereas, PCHE activity and DN in the plasma were 0.960 ± 0.12 units/ml and 84 ± 3, respectively.We also measured PCHE activity and DN in the CSF and plasma of 4 patients in whom there was a recent history of intraventricular bleeding. These patients had a CSF PCHE activity of 0.340 ± 0.07 units/ml (DN = 78 ± 3) and a plasma PCHE activity of 0.950 ± 0.10 units/ml (DN = 82 ± 2).Our data show that there is a low activity of PCHE in CSF, 1/20–1/100th that of plasma. Our data also show that PCHE activity increased to 1/4 to 1/2 that of plasma in CSF of patients with bleeding into CSF.