Rapid bedside rejuvenation of red blood cell with an autologous cell salvage device.

BACKGROUND AND OBJECTIVES: During storage, red blood cells (RBCs) undergo physicochemical changes which affect the quality, function, and in vivo survival of transfused packed RBCs (pRBC). Changes include decreased 2,3-diphosphoglycerate (2,3-DPG) levels, decreased ATP, changes in mechanical properties and oxidative injury. RBC rejuvenation is a method used to increase levels of 2,3-DPG and ATP in pRBCs. This process requires incubating the pRBCs with a rejuvenation solution and subsequent washing. Standard blood bank protocols using the COBE 2991 Cell Processor require several hours of preparation. The objective of this study was to verify if a bedside protocol for rejuvenating pRBC and washing with the Sorin Xtra autologous cell salvage system could be used. MATERIALS AND METHODS: Outdated pRBC units were obtained and rejuvenated in a model operating suite using a dry air incubator for 1 h at 37°C. Six units of pRBCs were pre-diluted with saline (1000 ml) and six units were not pre-diluted with saline. All units were washed with normal saline (1000 ml) using an apheresis-design cell salvage device in manual mode and wash volume set to 3000 ml. Samples were collected and analyzed for standard RBC quality parameters at baseline and post-wash. RESULTS: Total pRBC wash efficiency was 94% ± 12% at a final hematocrit of 67.7 ± 5.9% while maintaining post-wash hemolysis 0.24 ± 0.12 %. Pre-dilution prior to washing did not confer statistically significant differences in final RBC quality parameters with the notable exceptions of calculated hemolysis and supernatant potassium levels (P < 0.05). The washing process can be completed within 10 min. The post-wash RBC parameters are appropriate for immediate transfusion to patients.

The value of occlusive balloons in the management of abnormal placentation: A retrospective study.

Abnormal placentation is a potential cause of maternal morbidity and mortality from massive postpartum bleeding. The objective of this study was to investigate the efficacy of occlusive balloons when used as an adjunct to surgery in reducing blood loss and transfusion requirements. A retrospective study of 42 patients was performed involving consecutive cases of abnormal placentation who delivered with either conventional surgery with preoperatively placed occlusive balloons or conventional surgery alone. No differences were noted between the control group and the group of patients who had occlusive balloons with regard to estimated blood loss (P = 0.767), packed red blood cells transfused (P = 0.799), amount of crystalloids infused (P = 0.435), total procedure duration (P = 0.076), and length of ICU stay (P = 0.315) or total hospital stay (P = 0.254). Prophylactic intravascular balloon catheters did not benefit women with abnormal placentation when compared with conventional surgery alone.

Hypothermia attenuates NO production in anesthetized rats with endotoxemia.

Sepsis is often associated with upregulation of nitric oxide production and fever, and it is common to control an excessive febrile response with antipyretic therapy and external cooling. Our aim was to evaluate the effect of hypothermia on NO production in a model of septic shock. Rats were anesthetized, ventilated, and instrumented for hemodynamic monitoring and divided into four groups. Normothermic controls (NC) received saline intravenously and were maintained at 37 °C. Hypothermic controls (HC) received saline but were allowed to become hypothermic. Normothermic endotoxic (NE) received Escherichia Coli lipopolysaccharides (LPS) intravenously to induce endotoxic shock and was maintained at 37 °C. Hypothermic endotoxic (HE) received LPS intravenously and was allowed to become hypothermic. Exhaled NO (NOe) was measured from mixed expired gas at time zero and every 30 min, for 5 h. After injection of LPS, NOe increased substantially in the NE group (700 ± 24 ppb), but increased only to 25 ± 2 ppb in the HE group. NOe increased to 90 ± 3 ppb in the NC group, and to 17.6 ± 3.1 ppb in the HC group after 5 h (P < 0.05), whilst blood pressure remained stable. In the HE group, blood pressure fell immediately after injection of the LPS, but thereafter remained stable despite the rise in NOe. In the NE group, the blood pressure fell gradually, and the animals became hypotensive. During the natural course of endotoxemia in anesthetized rats, allowing severe hypothermia to ensue by not actively managing temperature and hemodynamics resulted in significantly reduced expired NO concentrations, lung injury, and prolonged survival. The clinical benefits of such a finding currently remain unclear and merit further investigation.

Cardiac manifestations of subarachnoid hemorrhage.

INTRODUCTION: Cardiac manifestations of intracranial subarachnoid hemorrhage patients include mild electrocardiogram variability, reversible left ventricular dysfunction (Takotsubo), non-ST elevation myocardial infarction, ST-elevation myocardial infarction and cardiac arrest, but their clinical relevance is unclear. The aim of the present study was to categorize the relative frequency of different cardiac abnormalities in patients with subarachnoid hemorrhage and determine the influence of each abnormality on outcome.  METHODS: A retrospective review of 617 consecutive patients who presented with non-traumatic aneurysmal subarachnoid hemorrhage at our institution was performed. A cohort of 87 (14.1%) patients who required concomitantly cardiological evaluation was selected for subgroup univariate and multi-variable analysis of radiographic, clinical and cardiac data.  RESULTS: Cardiac complications included myocardial infarction arrhythmia and congestive heart failure in 47%, 63% and 31% of the patients respectively. The overall mortality of our cohort (23%) was similar to that of national inpatient databases. In our cohort a high World Federation of Neurosurgical Surgeons grading scale and a troponin level >1.0 mcg/L were associated with a 33 times and 10 times higher risk of death respectively. CONCLUSIONS: Among patients suffering from cardiac events at the time of aneurysmal subarachnoid hemorrhage, those with myocardial infarction and in particular those with a troponin level greater than 1.0 mcg/L had a 10 times increased risk of death. 

Nitric oxide plays a minimal role in hypoxic pulmonary vasoconstriction in isolated rat lungs.

The goal of this study was to elucidate the importance of nitric oxide production during hypoxic pulmonary vasoconstriction (HPV). One group of Sprague Dawley rats received an ip injection of saline (controls), while a second group received an ip injection of Escherichia coli lipopolysacharides (LPS-treated) to render them septic. Three hours later, the animals were anesthetized and prepared for the isolated lung experiment. The lungs were ventilated and perfused with diluted autologous blood (Hct 23%) at constant flow rate while monitoring pulmonary arterial pressure (Pa). Nitric oxide production from the lungs was monitored by measuring its concentration in the mixed exhaled gas (NOe) offline. NOe in the isolated lungs was 2 ppb in controls and 90 ppb in the LPS treated lungs. Hypoxia caused Pa to rise from 10 to 17 mmHg in control lungs, and from 10 to 27 mmHg in the LPS treated lungs. NO production was then manipulated to determine if it affects HPV. NOe was increased by adding L-arginine to the blood, and was blocked by adding nitro-L-arginine (LNA). L-Arginine had minimal effect on NOe in control lungs, but increased NOe in LPS treated lungs, and yet HPV was similar in the 2 groups. Despite inhibition of NO synthesis with nitro-L-arginine (LNA), HPV was potentiated equally in control and in LPS treated lungs (Pa rose by 23 mmHg). Thus NO production did not affect the difference in HPV between control and LPS treated lungs. The results suggest that NO does not plays a primary role in HPV.

Evolution of segmental anesthesia for Laparo-Endoscopic Single Site (LESS) cholecystectomy.

AIM: Transumbilical Laparo-Endoscopic Single Site (LESS) surgery promises improved cosmesis, quick recovery, reduced postoperative pain and shorter length of hospital stay. Since only a simple umbilical incision is used, LESS surgery can be completed with segmental epidural anesthesia. This study describes the evolution of our technique of LESS cholecystectomy from a combination of spinal and epidural anesthesia to thoracic epidural alone and presents our experience with its safety, the observed morbidity, and the reported patient satisfaction. METHODS: In August 2009, a prospective evaluation of LESS cholecystectomy with regional anesthesia was undertaken. We recruited patients with chronic cholecystitis or symptomatic cholelithasis. Blood loss, operative time, complications, and length of hospital stay were measured. Preoperatively and 14 days postoperatively, outcome and symptom resolution were scored. RESULTS: Fifteen consecutive patients underwent LESS cholecystectomy; first with combined spinal-epidural (CSE), and then with thoracic epidural anesthesia alone. Immediate postoperative pain and discomfort were well tolerated. VAS scores upon admission to PACU were 0.4 (1.7±2.2). At postoperative day 14, the patients scored high values for "Satisfaction", 10 (10±1.0) and "Cosmesis", 10 (9.3±1.5). CONCLUSION: LESS cholecystectomy with epidural anesthesia can be undertaken safely. Patient satisfaction and cosmesis are particularly prominent amongst our patients. Our experience supports further utilization of epidural anesthesia for selected patients undergoing LESS cholecystectomy.

Patients selection for awake neurosurgery.

BACKGROUND: Based upon the surgical location and indication, including redundant regions, eloquent areas, deep brain stimulation, and epilepsy foci, some patients will benefit from an awake craniotomy, which allows completion of neurocognitive testing during the intra-operative period. This paper suggests patient selection criteria through a new decision algorithm. METHODS: We completed a retrospective chart review at Tampa General Hospital after IRB approval; data were obtained concerning total number of craniotomies, indications, and problems experienced for selection of awake vs. general anesthetic techniques. RESULTS: A total of 397 craniotomies were performed during the two years 2005 and 2006: among those 79 patients received an awake craniotomy (20%). We have utilized a sedation sequence which includes dexmedetomidine, propofol and LMA placement. A skull block is then performed to anesthetize pin placement, and desflurane and remifentanil are used for maintenance until the dural incision. At this time the inhalation agent is stopped and the LMA is removed while breathing spontaneously: the patient remains sedated on dexmedetomidine and remifentanil for the duration of the operation and can communicate effectively if closely coached. Analysis of all patient data led us to a decision tree to guide the surgeon and anesthesiologist in selecting the awake patients. DISCUSSION: We describe the sequence of steps and anesthetic agents which has proved successful for our group. Finally, the use of the proposed decision algorithm simplifies preoperative anesthetic selection and prevents erroneous assignment of inappropriate patients to an awake technique.

Malignant hyperthermia involving the administration of desflurane.

PURPOSE: This report describes an episode of malignant hyperthermia (MH) in a ten year old boy receiving desflurane anaesthesia. CLINICAL FEATURES: Following induction of general endotracheal anaesthesia with thiopentone and succinylcholine, desflurane was administered for maintenance of anaesthesia. Ten minutes after commencing desflurane administration, heart rate and PETCO2 increased to 165 bpm and 50 mmHg, respectively. Initially, the tachycardia was attributed to a sympathetic response secondary to desflurane. Desflurane was discontinued and isoflurane was started. Minute ventilation was increased to decrease PETCO2. Over the next five minutes, temperature increased to 38.4 degrees C as the PETCO2 increased to above 60 mmHg. Venous and arterial blood gases were drawn which showed acidosis and hypercapnia. Temperature and PETCO2 continued to increase, reaching peak values of 41 degrees C and 77 mmHg, respectively. Efforts to cool the patient were made. A total of 220 mg dantrolene sodium was administered iv. Following dantrolene, the temperature increase and acidosis subsided. Heart rate and PETCO2 decreased to 130 bpm and 36 mmHg, respectively. The surgical procedure was expeditiously performed. Postoperatively, in the Paediatric Intensive Care Unit, a dantrolene infusion of 20 mg.hr-1 was administered for 12 hr. The trachea was extubated the following morning. Several days later, the patient underwent another surgical procedure without complications using MH-safe anaesthetics. CONCLUSION: Onset of tachycardia in a patient receiving desflurane may initially be attributed to desflurane-induced sympathetic hyperactivity. This poses a clinical challenge in the diagnosis of MH during desflurane anaesthesia.

Left bronchial intubation by a single-lumen tube in adults: effects of bevel and curvature.

This study was designed to determine whether left bronchial intubation could be accomplished by reversal of the direction of the bevel or by changing the direction of curvature of a normal tracheal tube. The 60 study patients were divided into three groups. In group 1, the patients were intubated in the usual manner, with bevel to the left and the tube concave anteriorly. In group 2, the normal tracheal tube was rotated 90 degrees counterclockwise during insertion. In group 3, the bevel of the tracheal tube was altered to face the right, with the tube still concave anteriorly. In group 1, all 20 tracheal tubes entered the right primary bronchus. In group 2, 14 tracheal tubes (70%) entered the left primary bronchus. In group 3, 18 tubes entered the right primary bronchus and 2 entered the left. The position of the bevel did not influence the positioning of the tracheal tube in the right or left bronchus. In summary, 90 degrees counterclockwise rotation from the usual position and altering the concavity of the tube to face the left significantly increased the likelihood of intubation of the left primary bronchus.

Pneumothorax during laparoscopic Nissen fundoplication.

We present a case of 100% pneumothorax in a 41-yr-old man with a history of gastritis and gastroesophageal reflux scheduled for Nissen fundoplication. The patient was anaesthetized, and insufflation of the abdominal cavity with carbon dioxide was performed uneventfully. There was an increase in the peak inspiratory pressure and wheezing was noted with a decrease in the arterial oxygen saturation to 91%. An obstructive pattern was noted on the end tidal carbon dioxide monitor. The patient also had decreased breath sounds in the left lung field. The endotracheal tube was withdrawn 1.5 cm with equal breath sounds noted in both lung fields, but the wheezing persisted. At the end of the case the trocars were removed and the abdomen was deflated. The arterial oxygen saturation increased to 94% while breathing F1O2 of 1.0. A chest roentgenogram showed a 100% left pneumothorax. A left chest tube was placed with immediate improvement of the arterial oxygen saturation to 100%. We recommend monitoring of arterial oxygen saturation, peak inspiratory pressures, and excursion of the chest for early diagnosis and prompt treatment of pneumothorax during laparoscopic procedures.

Acute effects of intravascular absorption of 32% dextran 70 on blood coagulation, electrolytes and arterial blood gas.

Thirty-two percent dextran 70 is used to help visualize the uterine cavity during hysteroscopy and is also used intraperitoneally to prevent adhesions. We measured serum electrolytes, serum osmolarity, hematocrit, arterial blood gas and coagulation profile in 11 patients receiving dextran 70 while undergoing hysteroscopy. Dextran 70 had no significant effect on prothrombin time, partial thromboplastin time, thrombin time, fibrinogen level or serum osmolarity. There was a significant decrease in hematocrit, serum sodium and oxygen tension of arterial blood (PaO2). The decrease in sodium and hematocrit suggested hemodilution. This study demonstrated that 32% dextran 70 had a minimal effect on the majority of laboratory parameters measured.

Neural network-based detection of esophageal intubation.

To improve the accuracy of early detection of inadvertent esophageal intubation, we designed, trained, and tested a neural network-based computer system to detect the mechanical differences between lung and esophagogastric ventilation. Ten 25 to 30-kg anesthetized swine were sequentially ventilated with tidal volumes of 9, 12, and 15 mL/kg, using tubes placed in the trachea and in the esophagus, while flow and pressure waveforms were collected for 9-10 breaths. Gas remaining in the stomach was aspirated after each period of gastric ventilation. A computer program identified each mechanical inspiration, extracted the first 37 flow and pressure data points from each record, and normalized them to an equal amplitude. A back-propagation single-hidden-layer neural network was trained to identify the origin of flow and pressure waveforms as tracheal or esophageal. Ten different training and testing groups were assembled. In each group, data from nine subjects were used for training and data from the remaining subjects were used for testing. A total of 291 esophageal and 300 tracheal flow and pressure waveforms were analyzed by the network. The network identified esophageal intubation correctly during the first five breaths of all esophageal recordings. In one subject, the network identified the eighth esophageal breath as tracheal and could not identify three breaths. All tracheal intubations were identified correctly. Flow and pressure "signatures" of pulmonary and gastric ventilation are easily learned by a neural network. Therefore, neural-network recognition of esophageal intubation from flow and pressure signals is possible, and the development of an on-line detector for tracheal tube misplacement seems feasible.

False negative transesophageal echocardiography in a patient with severe mitral regurgitation.

We present a patient with severe mitral regurgitation, diagnosed by cardiac catheterization and physical examination but not seen on transesophageal echocardiography (TEE) after general anesthesia. Subsequently, transthoracic echocardiography was performed with the regurgitant jet visualized. This case illustrates one of the limitations of TEE secondary to the use of a biplane probe. The availability and routine use of an omniplane probe may prevent this limitation. A complement of physical examination, imaging, and diagnostic tools, as well as thorough understanding of the limitations of each technique, is essential.