Oxygen Reverses Deficits of Cognitive Function and Memory and Increased Heart Rate Induced by Acute Severe Isovolemic Anemia

Background: Erythrocytes are transfused to improve oxygen delivery and prevent or treat inadequate oxygenation of tissues. Acute isovolemic anemia subtly slows human data processing and degrades memory, increases heart rate, and decreases self-assessed energy level. Erythrocyte transfusion is efficacious in reversing these effects of acute anemia. We tested the hypothesis that increasing arterial oxygen pressure (Pao2) to 350 mmHg or greater would supply sufficient oxygen to be equivalent to augmenting hemoglobin concentration by 2-3 g/dl and thus reverse the effects of acute anemia.

Methods: Thirty-one healthy volunteers, aged 28 +/- 4 yr (mean +/- SD), were tested with verbal memory and standard, computerized neuropsychologic tests before and twice after acute isovolemic reduction of their hemoglobin concentration to 5.7 +/- 0.3 g/dl. Two sets of tests were performed in randomized order at the lower hemoglobin concentration: with the volunteer breathing room air or oxygen. The subject and those administering the tests and recording the results were unaware which gas was administered. As an additional control for duration of the experiment, 10 of these volunteers also completed the same tests on a separate day, without alteration of hemoglobin concentration, at times of the day similar to those on the experimental day. Heart rate, mean arterial blood pressure, and self-assessed sense of energy were recorded at the time of each test.

Results: Reaction time for digit-symbol substitution test increased, delayed memory was degraded, mean arterial pressure and energy level decreased, and heart rate increased at a hemoglobin concentration of 5.7 g/dl (all P < 0.05). Increasing Pao2 to 406 +/- 47 mmHg reversed the digit-symbol substitution test result and the delayed memory changes to values not different from those at the baseline hemoglobin concentration of 12.7 +/- 1.0 g/dl, and decreased heart rate (P < 0.05). However, mean arterial pressure and energy level changes were not altered with increased Pao2 during acute anemia.     

Acute Isovolemic Anemia Does Not Impair Peripheral or Central Nerve Conduction

Background: Previous studies have found subtle slowing of responses in tests of addition and digit-symbol substitution during acute severe isovolemic anemia to a hemoglobin concentration of 5 g/dl in healthy unmedicated humans. In this study, the authors tested the hypothesis that such changes relate to the slowing of afferent neural traffic.

Methods: The median nerve was stimulated at the wrist in seven healthy unmedicated volunteers before and after induction of acute isovolemic anemia to a nadir hemoglobin concentration of 5.1 +/- 0.3 g/dl (mean +/- SD). Times for neural impulses to travel from the stimulus site to the brachial plexus, cervical spinal cord, and cerebral cortex were measured using somatosensory evoked potentials. Tests were repeated during acute anemia with the subject breathing oxygen. As a control for time and intrasubject variation, the testing was repeated on a separate day when anemia was not produced at times equivalent to those on the experimental day.

Results: Induced acute severe isovolemic anemia decreased nerve conduction latencies from the wrist to the contralateral cerebral cortex (i.e., to the N20 peak) by 2.3 +/- 1.6% compared with values at a mean hemoglobin concentration of 12.7 g/dl (P < 0.01). These decreased latencies were due solely to an increased peripheral conduction velocity, from the wrist to the brachial plexus (P < 0.05), and were not altered when subjects breathed oxygen (P > 0.05). Conduction velocity from the brachial plexus or cervical spinal cord to the cerebral cortex did not change with acute anemia (P > 0.05). Latencies did not differ on the control day among the times of testing (all P > 0.05), nor did they differ at baseline between the control and experimental days (all P > 0.05).     

Blood ordering from the operating room: turnaround time as a quality indicator

BACKGROUND: Quality indicators in transfusion medicine are necessary for patient safety and customer satisfaction. The turnaround time (TAT) of issuing red blood cells (RBCs) has emerged as a quality indicator but is not an established benchmark. We examined the TAT for issuing RBCs from the blood bank to the operating rooms (ORs) at Vanderbilt University Medical Center (VUMC) and Stanford University Medical Center (SUMC). STUDY DESIGN AND METHODS: TAT was defined from time of request to when RBCs exited the blood bank. Cases eligible for analysis had completed type‐and‐screen results with requests for four or fewer RBC units. Patients with a positive antibody screen had serologically crossmatched units prepared and reserved for intraoperative use. We also e‐mailed surveys to academic institutions to establish the current state of TAT monitoring and to anesthesiologists at VUMC to gauge the TAT expectations of the OR. RESULTS: The mean TATs at the two institutions were comparable (VUMC, 10 ± 3.8 min; SUMC, 14 ± 7.2 min) for orders of RBCs. The most common reasons for delayed TAT were overlapping orders, medical technologists occupied by phone calls, and oversaturation of pneumatic tube stations. Only 3 of 24 surveyed institutions actively monitored RBC TAT. Surveyed anesthesiologists (n = 7) reported an expectation for RBC TAT of 5 to 15 minutes for urgent cases. Established internal TAT policies were 15 and 20 minutes at VUMC and SUMC, respectively, for crossmatched RBC requests for patients with complete diagnostic testing. CONCLUSION: Many of the surveyed institutions do not monitor stat RBC issue TAT as a quality indicator. This study serves as a starting point for establishing a benchmark for TAT for issuing RBCs from the blood bank to ORs.     

How we treat: transfusion medicine support of obstetric services

BACKGROUND: Obstetric services depend on the transfusion service (TS) to provide diagnostic testing and blood component therapy for clinical care pathways. STUDY DESIGN AND METHODS: We describe three quality improvement (QI) initiatives implemented to improve TS support of obstetric services. RESULTS: We implemented a pathway for patients requiring an ABO/Rh order for every admission to obstetric services, along with reconciliation of the daily hospital birth manifest and TS umbilical cord log to identify every woman eligible for RhIG. After assessment over 6 months, 21 (1%) of 2041 women lacked an admission ABO/Rh; all subsequently had ABO/Rh determinations. Umbilical cords were missing for eight (0.4%) mothers; four were D? and received RhIG. We developed algorithms for diagnostic blood ordering for patients deemed at “low,”“moderate,” or “high” risk of blood transfusion. A 27% reduction in total diagnostic test volumes and 24% reduction in charges was documented after compared to before implementation. We analyzed the impact of our massive transfusion protocol (MTP) on blood inventory management for 31 (0.25%) women undergoing 12,945 deliveries, representing 11% of 286 MTPs for all clinical services over a 32‐month interval. O? uncrossmatched red blood cells (RBCs) represented 103 (24%) of 421 RBC units issued. Wastage rates of RBCs, plasma, and platelets ordered and issued in the MTPs were 0.7, 16, and 3%, respectively. CONCLUSION: QI initiatives for RhIG prophylaxis, diagnostic blood test ordering, and MTP improve TS support of obstetric services.     

Informational Needs of Head and Neck Cancer Patients

The patient journey with head and neck cancer (HNC) is particularly challenging given the physical and functional impact of the cancer and treatment. The ability to perform activities of daily living can be severely compromised and have a profound impact on psychosocial well-being. These complex and long-lasting effects can affect patient quality of life for months to years and the literature shows that information for HNC patients is often insufficient. This observational cross-sectional study utilized survey methodology to investigate the informational needs of HNC patients and the preferred modalities for delivery. This was done to inform the development of resources for HNC patients. Four hundred fifty surveys were analyzed. The median age was 61 years and 58% of the cohort was born in Canada. Most were Caucasian (72%), Chinese being the next largest ethnicity (12%). A third had less than high school education and most had cancer of the oral cavity (28%) and were in long-term follow-up (41%). Comparison of the percentage of items to which a patient responded “very important” across the six domains shows variation of importance by domain (overall mixed effects regression model p < 0.0001). Additionally, each domain was compared to the medical domain and all had significantly lower mean scores (all p < 0.0001) with the medical domain scoring highest (mean score 64.6). The top preferred education modalities were teaching with a healthcare professional and pamphlets. This study highlights the type of information that HNC patients want and the format they wish to receive it in. The design provides a comprehensive way to consult with patients toward building education that responds to their specific needs.     

Experiences of patients with laryngectomies as they reintegrate into their community

Background  

The purpose of this qualitative study is to describe the patient’s experiences as they reintegrate into the community following laryngectomy surgery and identify their perceived support and barriers within this transition.