24-hour Recovery Research Articles

Positively charged porphyrins: a new series of photosensitizers for sterilization of RBCs.

Photodynamic treatment could be a way to inactivate pathogens in RBCs. The objective of this study was to characterize the virucidal activity and RBC-damaging activity of a series of cationic porphyrins. Using the most efficacious photosensitizer, various in-vitro human RBC quality variables and in-vivo RBC survival in Rhesus monkeys were evaluated. RBCs, spiked with 5 log of extracellular VSV, were treated with porphyrins (25 micro mol/L) and red light (100 W/m2) and essayed for virucidal activity. In-vitro RBC quality variables were assessed during 5 weeks of storage in various ASs. In-vivo survival was investigated with autologous RBCs in Rhesus monkeys. Tri-P(4) was by far the best sensitizer of a series tested, giving the least hemolysis under conditions that resulted in 5 log-kill of extracellular VSV. Under our experimental conditions, the percentage hemolysis in treated cells was 5.1 +/- 1.1 percent after 5 weeks of storage in SAG-M compared to 1.9 +/- 1.1 percent in the untreated control. Storage in AS-3 resulted hemolysis of 2.3 +/- 1.9 percent. With the exception of IgG binding and potassium leakage, RBC quality variables remained unchanged after photodynamic treatment. Addition of reduced glutathione (GSH) during treatment reduced IgG binding. The 24-hour recovery and T50 of treated RBCs in Rhesus monkeys were satisfactory. Porphyrin Tri-P(4) may be a suitable photosensitizer for sterilization of RBCs. However, further exploration to optimize the method is necessary to reach clinically acceptable goals.

COX-2 and iNOS in opioid-induced delayed cardioprotection in the intact rat

Cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) have been previously implicated in the late phase of cardioprotection associated with opioid-induced and ischemic preconditioning (IPC) in conscious rabbits and COX-2 in isolated rat hearts pretreated with an exogenous δ opioid agonist. However, it is not know if both iNOS and COX-2 mediate the late phase of cardioprotection induced by opioids in the intact blood-perfused rat. Therefore, we investigated the role of COX-2 and iNOS in the delayed phase of protection mediated by δ opioid receptor activation. Rats were pretreated 24 hours prior to an occlusion/reperfusion protocol with the selective non-peptide δ opioid agonists, BW373U86 (BW) and SNC-121 (SNC). NS-398, a selective COX-2 inhibitor was administered after the 24-hour recovery period just prior to index ischemia. The selective iNOS inhibitors, S-methylthiourea (SMT) and aminoguanidine (AG), were administered in conjunction with opioid pretreatment or were also given 24 hours after opioid administration just prior to index ischemia. COX-2 inhibition by NS-398 given 24 hours after opioid administration attenuated the protective effects of both BW and SNC (46 ± 6 vs. 13 ± 3 and 51 ± 5 vs. 29 ± 2, p < 0.001, respectively). Similarly, inhibition of iNOS following 24 hours of treatment with opioids also attenuated the protective effects of BW and SNC. However, the delayed protective effects of the opioids were not attenuated by pretreatment with the iNOS inhibitors 24 hours prior to the infarct protocol. These results suggest that both COX-2 and iNOS are mediators of delayed protection induced by non-peptide δ opioid agonists. It appears that the trigger effect is not dependent on the activity of iNOS or COX-2 but the late phase of cardioprotection is dependent on the upregulation of these enzymes.

Flow-Cytometric Determination of Survival Time and 24-Hour Recovery of Transfused Red Blood Cells

Introduction: We tested the feasibility of the determination of 24-hour recovery and survival time of transfused red blood cells (RBCs) by flow cytometry to evaluate a new RBC preparation in a clinical application study. Patients and Methods: Eleven patients received 22 inline filtered RBC concentrates from apheresis (mean storage time of transfused RBCs 25.6 ± 12 days). Recovery and survival were calculated based on flow-cytometric determination of autologous and transfused RBCs by measuring antigens differing between donor and recipient. Human polyclonal erythrocyte antibodies (IgG) were used as primary and FITC-conjugated rabbit antihuman IgG antibody (F(ab’)₂) fragments as secondary antibodies. Results: The mean (± SD), 24-hour recovery determined, using anti-c, anti-C, anti-D, anti-Jk^a and anti-Fy^a as primary antibodies, was 78 ± 12%, the mean RBC survival time was 70.1 ± 26.5 days. Discussion: Flow cytometry using blood group antigen differences between donor and recipient appears to be suitable for the determination of RBC 24-hour recovery and survival time. This method requires no pretransfusional labeling of the RBCs, thus avoiding any bias by manipulation of the transfused RBCs. However, this method is applicable only to allogeneous transfusion.

Use of an inspiratory impedance valve improves neurologically intact survival in a porcine model of ventricular fibrillation.

This study evaluated the potential for an inspiratory impedance threshold valve (ITV) to improve 24-hour survival and neurological function in a pig model of cardiac arrest. Using a randomized, prospective, and blinded design, we compared the effects of a sham versus active ITV on 24-hour survival and neurological function. After 6 minutes of ventricular fibrillation (VF), followed by 6 minutes of cardiopulmonary resuscitation (CPR) with either a sham or an active valve, anesthetized pigs received 3 sequential 200-J shocks. If VF persisted, they received epinephrine (0.045 mg/kg), 90 seconds of CPR, and 3 more 200-J shocks. A total of 11 of 20 pigs (55%) in the sham versus 17 of 20 (85%) in the active valve group survived for 24 hours (P<0.05). Neurological scores were significantly higher with the active valve; the cerebral performance score (1=normal, 5=brain death) was 2.2+/-0.2 with the sham ITV versus 1.4+/-0.2 with the active valve (P<0.05). A total of 1 of 11 in the sham versus 12 of 17 in the active valve group had completely normal neurological function (P<0.05). Peak end-tidal CO2 (PETCO2) values were significantly higher with the active valve (20.4+/-1.0) than the sham (16.8+/-1.5) (P<0.05). PETCO2 >18 mm Hg correlated with increased survival (P<0.05). Use of a functional ITV during standard CPR significantly improved 24-hour survival rates and neurological recovery. PETCO2 and systolic blood pressure were also significantly higher in the active valve group. These data support further evaluation of ITV during standard CPR.

First In Vitro and In Vivo Experiences with Stay·Safe Balance, A pH-Neutral Solution in a Dual-Chambered Bag

In addition to low pH and high osmolarity, glucose degradation products (GDPs) are considered to play a major role in the bioincompatibility of peritoneal dialysis fluids (PDFs). The formation of GDPs can be reduced by separating the glucose component of the solution (kept at very low pH) from the lactate component of the solution (kept at alkaline pH) during sterilization and storage. This development has been achieved by the use of a dual-chambered bag. Immediately before infusion, the seam between the two chambers is opened, and the contents are mixed. The result is a fluid with a more physiologic pH in the range 6.8 - 7.4. Concentrations of 3-deoxyglucosone (3-DG), methylglyoxal (MG), acetaldehyde (AA), and formaldehyde (FA) in Stay-Safe Balance (Fresenius Medical Care, Bad Homburg, Germany) were remarkably reduced when compared to conventional PD solution [conventional PDF (1.5% glucose): 172 micromol/L, 6 microLmol/L, 152 micromol/L, and 7 micromol/L respectively; Stay-Safe Balance (1.5% glucose): 42 micromolL, < 1 micromol/L, < 2 micromol/L, and < 3 micromol/L respectively; conventional PDF (4.25% glucose): 324 micromol/L, 10 micromol/L, 182 micromol/L, and 13 micromol/L respectively; Stay-Safe Balance (4.25% glucose): 60 micromol/L, < 1 micromol/L, < 2 micromol/L, and < 3 micromol/L respectively). Human peritoneal mesothelial cells (HPMCs) were exposed to a control solution, a conventional PDF [CAPD 2, 1.5% glucose (Fresenius Medical Care, Bad Homburg, Germany)], and Stay-Safe Balance, either in a co-incubation model (24-hour PDF exposure) or in a pre-incubation model (30-min PDF exposure), followed by 24-hour recovery in culture medium. Interleukin-1beta (IL-1beta)-stimulated (1 ng/mL) IL-6 secretion from HPMCs was assessed by ELISA. Exposure of HPMCs to conventional PDF resulted in a significant reduction in IL-6 release, which was fully restored following exposure to Stay-Safe Balance. In addition to the short-term investigations, long-term in vitro studies were also carried out. All fluids had near-neutral pH and were changed every second day. After 1, 3, 5, 7, 10, and 13 days of exposure, cell viability was assessed. Whereas exposure to conventional PDF resulted in a significant reduction in HPMC viability after just 3 - 5 days, no significant toxicity of filter-sterilized or dual-chambered fluid was observed for up to 13 days. An observational study with 9 patients suggested that the efficacy of Stay-Safe Balance is equivalent to that of conventional solution. However, even short-term treatment (8+/-1 weeks) with this more biocompatible solution seems to improve mesothelial cell mass as indicated by a rise in cancer antigen 125 (CA125) from a baseline of 47+/-37 U/min to 172+/-90 U/min. Our data indicate that Stay-Safe Balance may help to better preserve peritoneal membrane cell function. An ongoing European multicenter study is expected to confirm these results.

Evaluation of an automated system for the collection of packed RBCs, platelets, and plasma.

This study evaluated the quality of WBC-reduced platelets, RBCs, and plasma collected on a new system (Trima, Gambro BCT) designed to automate the collection of all blood components. The study also evaluated donor safety and suitability of these components for transfusion. In Phase I, the quality of the components collected on the new system was evaluated by standard in vitro and in vivo testing methods. Results were compared to those from control components collected by currently approved standard methods. In Phase II, additional collections were performed to evaluate the acceptability of the new system and the safety of platelets collected. In vivo 24-hour RBC recovery was 76.8 +/- 3.1 percent for the test RBC units and 77.1 +/- 4.4 percent recovery for whole-blood (control) RBCs. The differences between test and control platelet results in the in vivo and in vitro assays were not clinically significant. Plasma clotting factors and fibrinogen levels met international standards. The system was well accepted by donors, and no major adverse donor reactions were reported for the 68 procedures performed. No problems were reported with transfusing the blood components collected. Blood components collected with the Trima are equivalent to currently available components, and they meet the applicable regulatory standards. This system provides consistent, standardized components with predictable yields. It provides the option of fully automating the collection of all blood components.

Guidelines for less than 24-hour aftercare recovery units

“Managing Your OR” focuses on various aspects of aesthetic surgery in the ambulatory surgical setting.

The Effects of NCAA Division 1 Intercollegiate Competitive Tennis Match Play on Recovery of Physical Performance in Women

The effects of 2 days of Big Ten National Collegiate Athletic Association Division 1 tennis match play were studied in 7 women. The unique design of this study was the first to use an actual collegiate match-play situation incorporating all of the actual stresses involved in the multidimensional game of tennis. Physical strength, power, and several physiological measures were evaluated in an attempt to identify specific variables created by the demands of actual play that may not recover from fatigue. The test battery included determination of peak ball velocity in the serve, peak torque of both internal and external shoulder rotation, maximal grip strength, vertical jumps on the force plate, and salivary cortisol concentrations. Prior to the study, baseline measures for the test battery were established with reliabilities of intraclass correlation coefficients of R ≥ 0.95. Each performance variable sufficiently recovered after 24 hours; no significant differences were observed between baseline and the test session 24 hours postmatch. Significant (p <0.05) correlations were observed between force variables of the dominant playing arm and the performance variable of serve velocity (r = 0.75–0.82). It appears that a 24-hour recovery period will allow a majority of a tennis player's neuromuscular performance characteristics to recover from successive days of collegiate match-play competition; however, mental and physical perceptions of fatigue may still exist.

Comparison of 3 different anesthetic techniques on 24-hour recovery after otologic surgical procedures

Intravenous propofol anesthesia is better than inhalational anesthesia for otologic surgery, but cost and intraoperative movement make this technique prohibitive. This study compares a propofol sandwich anesthetic with a total propofol or inhalational anesthetic for otologic surgery to determine which produces the best perioperative conditions and least expense. One hundred twenty patients undergoing ear surgery were randomly chosen to receive an anesthetic with either isoflurane (INHAL), total propofol (TPROP), or propofol used in conjunction with isoflurane (PSAND). Postoperative wakeup and the incidence and severity of nausea, vomiting, and pain were compared among groups. Antiemetic administration and discharge times from recovery and the hospital were also compared. The groups were similar, but anesthesia times were longer in the INHAL group. Emergence from anesthesia after PSAND or TPROP was more rapid than after INHAL. Recovery during the next 24 hours was associated with less nausea and vomiting with PSAND than with INHAL. The cost of the PSAND anesthetic was similar to that of INHAL, and both were less than TPROP. PSAND anesthesia may be similar to TPROP and better than INHAL for otologic procedures. PSAND was less expensive than TPROP and produced a similar recovery profile and antiemetic effect in the 24-hour period after surgery. (Otolaryngol Head Neck Surg 1999;120:406-11.)

Evaluation of in vivo and in vitro Quality of Apheresis‐Collected RBC Stored for 42 Days

New technological developments make it possible to collect red blood cells (RBCs) by apheresis, which allows for better product consistency and has the potential for improved RBC quality. The purpose of these studies was to evaluate the quality and consistency of units of RBCs collected by apheresis using the MCS+(R) machine (Haemonetics Corp., Braintree, Mass., USA). Two studies were performed. In study 1 (n = 10), using containers and CP2D/AS-3 solutions from Medsep Corp. (Covina, Calif. USA), one-unit apheresis RBCs were compared to manually collected RBCs in a random crossover design. In study 2 (n = 12), 6 subjects had one unit collected, while the remaining 6 subjects had two units of RBCs collected with comparison to previously manually collected RBCs from the same donors. Haemonetics containers and solutions were used in study 2. Low RBC volume variability was found for the apheresis collections with a standard deviation of only 6 ml difference between actual and target volumes. Combining the data from the two studies (n = 21 pairs), at 42 days of storage, the apheresis units showed slightly lower hemolysis (0.44+/-0.26 vs. 0.61+/-0.50%), lower supernatant potassium levels (50+/-3 vs. 53+/-3 mEq/l), and improved tolerance to osmotic shock (47+/-3 vs. 49+/-3%) as compared to manual units (p < 0.05). There was no statistically significant difference in RBC ATP (3.0+/-0.6 vs. 2.9+/-0.5 micromol/g Hb) or in 24-hour percent recoveries (81+/-6 for apheresis vs. 81+/-4% for apheresis red cells). Apheresis RBC quality was not affected by the manufacturer (Haemonetics vs. Medsep) of solutions and containers. RBC units collected by apheresis demonstrated low variability in volume of RBC mass collected, and showed similar RBC properties as compared to manually collected RBCs after processing and after 42 days of storage.

Evaluation of in vivo and in vitro Quality of Apheresis-Collected RBC Stored for 42 Days

Background and Objectives: New technological developments make it possible to collect red blood cells (RBCs) by apheresis, which allows for better product consistency and has the potential for improved RBC quality. The purpose of these studies was to evaluate the quality and consistency of units of RBCs collected by apheresis using the MCS+® machine (Haemonetics Corp., Braintree, Mass., USA). Materials and Methods: Two studies were performed. In study 1 (n = 10), using containers and CP2D/AS-3 solutions from Medsep Corp. (Covina, Calif. USA), one-unit apheresis RBCs were compared to manually collected RBCs in a random crossover design. In study 2 (n = 12), 6 subjects had one unit collected, while the remaining 6 subjects had two units of RBCs collected with comparison to previously manually collected RBCs from the same donors. Haemonetics containers and solutions were used in study 2. Results: Low RBC volume variability was found for the apheresis collections with a standard deviation of only 6 ml difference between actual and target volumes. Combining the data from the two studies (n = 21 pairs), at 42 days of storage, the apheresis units showed slightly lower hemolysis (0.44±0.26 vs. 0.61±0.50%), lower supernatant potassium levels (50±3 vs. 53±3 mEq/l), and improved tolerance to osmotic shock (47±3 vs. 49±3%) as compared to manual units (p < 0.05). There was no statistically significant difference in RBC ATP (3.0±0.6 vs. 2.9±0.5 μmol/g Hb) or in 24-hour percent recoveries (81±6 for apheresis vs. 81±4% for apheresis red cells). Apheresis RBC quality was not affected by the manufacturer (Haemonetics vs. Medsep) of solutions and containers. Conclusions: RBC units collected by apheresis demonstrated low variability in volume of RBC mass collected, and showed similar RBC properties as compared to manually collected RBCs after processing and after 42 days of storage.

Time course of gastrointestinal tract permeability to chromium 51-labeled ethylenediaminetetraacetate in healthy dogs

Abstract Objectives To establish values for gastrointestinal tract permeation by chromium 51-labeled ethylenediaminetetraacetate (51Cr-labeled EDTA) in healthy adult dogs, and to evaluate the time course for 51Cr-labeled EDTA absorption over a 24-hour period after its administration, in an effort to define a shorter, more practical collection method. Animals 6 healthy adult mixed-breed dogs. Procedure After an 18-hour nonfeeding period, each dog was given a solution containing 50 μCi of 51Cr-labeled EDTA in deionized water (10 ml/kg of body weight) by stomach tube. Complete urine collection was done at 2, 4, 6, and 24 hours after 51Cr-labeled EDTA administration. Five-milliliter samples of urine were counted for 15 minutes in a gamma counter, and radioactivity in urine was expressed as a percentage of the orally administered dose. Results Median (range) 24-hour urinary recovery of 51Cr-labeled EDTA after 24 hours was 15.1 (12.7 to 20.3)%. Urine collected at 2, 4, and 6 hours contained 1.0 (0.2 to 3.5)%, 6.5 (2.2 to 8.7)%, and 10.0 (8.1 to 11.7)% of the administered 51Cr-labeled EDTA, respectively. Urine passed during the first 6 hours contained, on average, 67 (54 to 77)% of the total 24-hour urine recovery. Conclusions 6-hour urinary recovery of 51Cr-EDTA provides a potential alternative to 24-hour recovery. This shorter collection period may more specifically reflect small intestinal permeability. (Am J Vet Res 1998; 59:1113-1115)

Effect of vacuolar proton ATPase on pHi, Ca2+, and apoptosis in neonatal cardiomyocytes during metabolic inhibition/recovery.

Recently, we found that vacuolar proton ATPase (VPATPase) operates in cardiomyocytes as a complementary proton-extruding mechanism. Its activity was increased by preconditioning with resultant attenuation of intracellular acidification during ischemia. In this study, we examined whether VPATPase-mediated proton efflux during metabolic inhibition/recovery may spare Na+ overload via Na+-H+ exchange, attenuate Na+-Ca2+ exchange, and decrease apoptosis. Neonatal rat cardiomyocytes were subjected to 2- to 3-hour metabolic inhibition with cyanide and 2-deoxyglucose and 24-hour recovery. The effect of VPATPase inhibition by 50 nmol/L bafilomycin A1 on apoptosis, pHi, and [Ca2+]i was studied by flow cytometry with propidium iodide, seminaphthorhodafluor (SNARF)-1-AM, and indo-1-AM staining, respectively. VPATPase inhibition increased the amount of apoptosis measured after 24 hours of recovery and abrogated the protective effect of inhibition of Na+-H+ exchange by (5-N-ethyl-N-isopropyl)amiloride (EIPA). Dual blockade of VPATPase and Na+-H+ exchange was additive in effect with EIPA on pHi during metabolic inhibition/recovery and recovery from the acid challenge with sodium propionate. VPATPase blockade increased the rate of accumulation of intracellular Ca2+ at the beginning of metabolic inhibition and abrogated the delaying effect of EIPA on intracellular Ca2+ accumulation. These results indicate that VPATPase plays an important accessory role in cardiomyocyte protection by reducing acidosis and Na+-H+ exchange-induced Ca2+ overload.

Total energy expenditure in patients with small-cell lung cancer: Results of a validated study using the bicarbonate-urea method

The bicarbonate-urea method for measuring CO2 production was applied to eight free-living patients (mean age, 68 ± 10 years; mean weight, 69 ± 10 kg; mean height, 1.65 ± 0.10 m) with unresectable small-cell lung cancer for a period of 1 day (n = 5) or 2 days (n = 3). The basal metabolic rate (BMR) was measured in all subjects. The technique was first validated against whole-body indirect calorimetry over an additional 24-hour period in five of these subjects. The bicarbonate-urea method predicted net CO2 production to be 102.1 ± 3.4% of that measured by whole-body indirect calorimetry, and energy expenditure, 101.5% ± 3.8% of the measured calorimeter value (8.1 ± 1.6 MJ/d). The 24-hour recovery of label in CO2 excreted by the body was 95.6% ± 0.5%. In free-living conditions, the bicarbonate-urea method predicted energy expenditure to be 9.0 ± 2.6 MJ/d. BMR was elevated by a mean of 6% (P < .05) compared with the Schofield standards. The physical activity level ([PAL] the ratio of total energy expenditure [TEE] to BMR) was variable (1.15 to 1.87), but the mean value was only 1.36 ± 0.22, considerably less than that of moderately active healthy subjects with estimated PAL values of 1.55 (P < .05) to 1.65 (P < .01) and the mean results obtained by doubly labeled water (previous studies) in healthy age- and sex-matched subjects. This is the first time a tracer method for measuring CO2 production and energy expenditure has been validated against whole-body 24-hour indirect calorimetry in patients with lung cancer or a systemic inflammatory reaction. The agreement between the two methods is similar to that observed in normal subjects. This is also the first time a tracer method has been used to measure energy expenditure in free-living patients with lung cancer. The results suggest that TEE and the energy requirements necessary to maintain energy balance were not increased despite basal hypermetabolism, because of the associated decrease in physical activity.

Carotid artery and jugular vein ligation with and without hypoxia

A continuing concern about the use of extracorporeal membrane oxygenation (ECMO) is the cannulation of the common carotid artery or the internal jugular vein. The authors investigated the changes that might occur in the brain with neck vessel ligation in the normal and the hypoxic rat. Two groups of 60 rats each were studied. The first group was divided into three subgroups of 20 animals each. Subgroup 1 (HH) was hypoxic both 24 hours before and 24 hours after operation. Subgroup 2 (HN) (the ECMO model) was hypoxic before operation and recovered for 24 hours in room air. Subgroup 3 (NN) underwent the entire procedure in room air. For each oxygen environment, four different operations were performed: carotid artery ligation, jugular vein ligation, carotid artery and jugular vein ligation, and dissection of the vessels without ligation (sham). Thus each subgroup was further divided into four sub-subgroups based on the operation performed. Rats were again anesthetized after a 24-hour recovery period and killed using low, blunt cervical dislocation. In the first group of 60 rats, the skull was opened and the brain was carefully removed from the cranial vault and placed in a fixative. The brains were placed in a small magnetic resonance imaging (MRI) head coil in groups of five and scans were obtained to provide T 1 and T 2 images that correlated with histological sections. MRI scans were reviewed in random, blinded fashion by an imager unaware of how these animals had been treated. The brains were then sectioned coronally at six corresponding levels: frontal, mid and posterior cerebrum, midbrain, pons, and medulla. Histological examination was performed in blinded fashion. The number of lesions (usually ischemic as noted by a decrease in the number of neurons) was totaled for each area of the brain. There were no differences that were consistent or statistically significant in the MR images of brains removed from the head, although it would appear that rats with jugular vein and carotid artery ligation were relatively protected. In the HN group jugular vein ligation was worst, and adding carotid artery ligation was best. In the histological studies the NN group had significantly more lesions than the HH group ( P < .01). The second group of 60 rats was divided and treated as the first group in all respects except that MRI was conducted immediately after death on intact heads, and no histological studies were performed. This was done to control for lesions that might have been produced by removal of the brains from the skulls. In this group all findings were right sided. One animal in the HN group showed midcerebral white matter edema after jugular and carotid ligation. Focal anterior cerebral edema was seen in another animal (HH) after isolated carotid ligation. An occipital infarct was found in one animal (HH) after both carotid and jugular ligation. The authors conclude that neck vessel ligation in the hypoxic or normoxic rat causes only occasional and sporadic brain injury much as is seen clinically in newborn ECMO patients.

The irradiation of blood and blood components to prevent graft-versus-host disease: technical issues and guidelines.

In recent years, there have been several advances in blood irradiation practice. These include a better definition of the most appropriate dose level that should be used when irradiating blood components. Commercial innovation has provided the tools for a quality assurance program to assess the dose that is delivered throughout the canister in a free-standing irradiator, and, through the use of radiation-sensitive indicator labels, to confirm that the irradiation process has taken place. With the apparent increased use of linear-accelerators to irradiate blood components, appropriate quality assurance measures need to be developed. The maximum storage period for irradiated red cells should be shorter than for nonirradiated red cells if the treatment is performed early during the storage period because irradiation reduces the in vivo 24-hour red cell recovery parameter. The storage period for irradiated platelets does not need to be modified. Some questions are being raised regarding whether fresh-frozen plasma should be irradiated to inactivate a small number of immunocompetent progenitor cells that may be present. Table 4 summarizes the practices that should be followed in connection with the technical issues that have been addressed in this article. These guidelines follow the recommendations issued in July 1993 by the FDA in the United States. This article and Tables 1 and 2 contain additional guidelines.

Functional and structural alterations with 24-hour myocardial hibernation and recovery after reperfusion. A pig model of myocardial hibernation.

Short-term myocardial hibernation of 3 hours resulting from a moderate resting coronary flow reduction has been reproduced in pigs. This study was designed to determine whether any structural changes accompany short-term hibernation caused by a moderate flow reduction maintained for 24 hours and whether any such structural alterations are reversible after reperfusion. A severe left anterior descending coronary artery (LAD) stenosis was created with a reduction of resting flow to approximately 60% of baseline and maintained for 24 hours. Regional coronary flow was measured by a flowmeter; wall thickening was determined by echocardiography, and local metabolic changes were measured. Of 17 pigs, 11 completed the study protocol of 24 hours. The LAD flow was reduced from 0.91 +/- 0.11 to 0.52 +/- 0.13 mL.min-1.g-1, a 43% mean decrease, at 15 minutes after the LAD stenosis and was maintained at 0.56 +/- 0.11 mL.min-1.g-1 at 24 hours. The reduction of regional coronary flow initially produced acute myocardial ischemia, as evidenced by reduced regional wall thickening (from 37.2 +/- 6.9% at baseline to 11.5 +/- 6.8%), regional lactate production (-0.34 +/- 0.28 mumol.g-1.min-1), and a decrease in regional coronary venous pH (from 7.41 +/- 0.035 at baseline to 7.30 +/- 0.030). At 24 hours, the reductions in coronary flow and wall thickening were maintained relatively constant and the rate-pressure product was relatively unchanged, but lactate production ceased and regional H+ concentration normalized, with a tendency toward a further reduction in regional oxygen consumption, from 3.10 +/- 0.90 mL.min-1.100 g-1 at 15 minutes after stenosis to 2.52 +/- 0.95 mL.min-1.100 g-1 at 24 hours (P = .06), indicating metabolic adaptation of the hypoperfused regions. Of 11 pigs, 6 were free of myocardial infarction; 3 had patchy necrosis involving 4%, 5%, and 6% of the area at risk; and 2 other pigs had a few scattered myocytes with necrosis, detected only by light and electron microscopy. Ultrastructural changes consisted of a partial loss of myofibrils and an increase in mitochondria and glycogen deposition. Regional wall thickening recovered 1 week after reperfusion in most pigs, and the ultrastructural changes reverted to normal. In this pig model, moderately ischemic myocardium undergoes metabolic and structural adaptations but preserves the capacity to recover both functionally and ultrastructurally after reperfusion.

Intestinal Permeability, Gastric Intramucosal pH, and Systemic Endotoxemia in Patients Undergoing Cardiopulmonary Bypass

To examine the relationship between gastric intramucosal pH, intestinal permeability, endotoxemia, and oxygen delivery in patients undergoing cardiopulmonary bypass (CPB). Prospective, observational study. Tertiary care center. Fifty patients undergoing elective cardiac surgery and 10 patients awaiting elective cardiac surgery. Patients received chromium 51-labeled ethylenediaminetetraacetic acid (51Cr-EDTA) as a marker of intestinal permeability; insertion of a nasogastric tonometer to measure intramucosal pH (pHi); insertion of a pulmonary artery catheter to measure systemic oxygen delivery and consumption variables; arterial blood sampling for plasma endotoxin by the Limulus amebocyte lysate assay; and blood and urine sampling for measurement of 51Cr-EDTA. Systemic oxygen delivery, duration of gastric mucosal acidosis, absorption of 51Cr-EDTA, appearance of systemic endotoxemia, renal dysfunction, and duration of hospital stay. Median (range) 24-hour urinary recovery of 51Cr-EDTA in patients was 10.6% (2.1% to 40.2%) while that in controls was 1.2% (0.7% to 2.0%, P<.001). Intestinal permeability increased during CPB. The median (range) for the lowest pHi after bypass was 6.98 (6.74 to 7.17). The pHi did not decline until CPB was discontinued and the heart took over the load of the circulation. Endotoxin was detectable (>0.2 endotoxin unit per milliliter) in the plasma of 21 patients (42%) during the study, most of whom were endotoxemic by the end of CPB. There was no evident relationship between the degree of gut permeability, endotoxemia, gut ischemia, or systemic oxygen dynamics. Cardiopulmonary bypass is associated with increases in gut permeability, which precede gut mucosal ischemia. In cardiac surgical patients, a low pHi is not necessarily indicative of an adverse clinical outcome. Endotoxemia as measured by the Limulus amebocyte lysate assay is common. The increased intestinal absorption of 51Cr-EDTA and gastric mucosal acidosis occur as independent phenomena and are not related in severity or time of onset.

Studies in red blood cell preservation 10. 51Cr recovery of red cells after liquid storage in a glycerol-containing additive solution.

The purpose of the present study was to compare the 24-hour recovery of red blood cells stored for 9 weeks in a hypoosmolar additive solution containing 150 mM glycerol to cells stored in Adsol. Seven units of packed red cells were split into 2 aliquots. To one sample, 100 ml of the experimental additive solution (EAS 25) was added, and to the other, 50 ml of Adsol. At the end of the storage period the cells were labeled with 51Cr. A double chromium technique was used to make it possible to perform comparative autologous studies in the same donor. The 24-hour 51Cr recovery value for EAS 25 was 73.0 +/- (SD) 4.2% and for Adsol 60.9 +/- 7.1. At 9 weeks the adenosine triphosphate levels were not significantly better compared to Adsol but the other in vitro measurements were better. New approaches to the study of red cell preservation are suggested.

Studies in Red Blood Cell Preservation 10.(51)Cr Recovery of Red Cells after Liquid Storage in a Glycerol-Containing Additive Solution

The purpose of the present study was to compare the 24-hour recovery of red blood cells stored for 9 weeks in a hypoosmolar additive solution containing 150 mM glycerol to cells stored in Adsol®. Seven units of packed red cells were split into 2 aliquots. To one sample, 100 ml of the experimental additive solution (EAS 25) was added, and to the other, 50 ml of Adsol. At the end of the storage period the cells were labeled with 5lCr. A double chromium technique was used to make it possible to perform comparative autologous studies in the same donor. The 24-hour 51 Cr recovery value for EAS 25 was 73.0±(SD) 4.2% and for Adsol 60.9±7.1. At 9 weeks the adenosine triphosphate levels were not significantly better compared to Adsol but the other in vitro measurements were better. New approaches to the study of red cell preservation are suggested.