Baroreflex sensitivity during noxious stimulation in vasovagal reactors to blood donation

Incidence and risk predictors analysis of adverse donor reactions in whole blood donation

OBJECTIVE

Adverse donor reactions in normal healthy blood donors is not unusual. However, these unpleasant effects have a negative impact on donor retention. Adverse event due to blood donation is multifactorial in origin. Therefore, the objective of this study was to determine the frequency and type of adverse donor reactions during or after blood donation. More importantly, this study also aimed at analyzing important risk predictors of adverse donor reaction.

MATERIAL AND METHODS

This was a retrospective study conducted from May 2017 to April 2019 in the department of Transfusion Medicine at a tertiary care center in eastern India. Data were stored in Microsoft excel 2016 by using a standardized format as per ISBT criteria and analyzed with software "R, version 3.5.3" to find out the various independent precipitating factor.

RESULTS

Overall, 107 donors (0.98%) experienced adverse events with 10,814 whole blood donations. The first time, females, younger age donors (18-30 years), and donors with a mean arterial blood pressure of less than 90mm of Hg were the most important independent risk factors predicting the possibility of adverse donor reaction. Donors' weight, hemoglobin, and the type of donation had not affected the frequency of adverse events.

CONCLUSION

Analysis of adverse donor reactions helps in selecting the blood donors who are at risk of donor reactions. Our study highlights the importance of proper predonation screening especially in terms of assessment of mean blood pressure, along with identification of first time and female blood donors in order to reduce untoward donor reaction.

Chronic pain-related changes in cardiovascular regulation and impact on comorbid hypertension in a general population: the Tromsø study

Heart rate variability (HRV) and baroreflex sensitivity (BRS) are indexes reflecting the ability to maintain cardiovascular homeostasis amidst changing conditions. Evidence primarily from small studies suggests that both HRV and BRS may be reduced in individuals with chronic pain (CP), with potential implications for cardiovascular risk. We compared HRV and BRS between individuals with CP (broadly defined) and pain-free controls in a large unselected population sample. Participants were 1143 individuals reporting clinically meaningful CP and 5640 pain-free controls who completed a 106-second cold pressor test (CPT). Participants self-reported hypertension status. Resting HRV and BRS were derived from continuous beat-to-beat blood pressure recordings obtained before and after the CPT. Hierarchical regressions for the pre-CPT period indicated that beyond effects of age, sex, and body mass index, the CP group displayed significantly lower HRV in both the time domain (SDNN and rMSSD) and frequency domain (high-frequency HRV power), as well as lower BRS. Results were somewhat weaker for the post-CPT period. Mediation analyses indicated that for 6 of 7 HRV and BRS measures tested, there were significant indirect (mediated) effects of CP status on the presence of comorbid hypertension via reduced HRV or BRS. Results confirm in the largest and broadest sample tested to date that the presence of CP is linked to impaired cardiovascular regulation and for the first time provide support for the hypothesis that links between CP and comorbid hypertension reported in previous population studies may be due in part to CP-related decrements in cardiovascular regulation.

Adverse Reactions in Allogeneic Blood Donors: A Tertiary Care Experience from a Developing Country

OBJECTIVES

Fragmented blood transfusion services along with an unmotivated blood donation culture often leads to blood shortage. Donor retention is crucial to meet the increasing blood demand, and adverse donor reactions have a negative impact on donor return. The aim of this study was to estimate adverse donor reactions and identify any demographic association.  .

METHODS

We conducted a prospective study between January 2011 and December 2013. A total of 41,759 healthy donors were enrolled. Professionally trained donor attendants drew blood and all donors were observed during and following donation for possible adverse events for 20 minutes. Blood donors were asked to report if they suffered from any delayed adverse consequences.  .

RESULTS

Out of 41,759 blood donors, 537 (1.3%) experienced adverse reactions. The incidence was one in every 78 donations. The mean age of donors who experienced adverse events was 26.0±6.8 years, and all were male. Out of 537 donors, 429 (80%) developed vasovagal reaction (VVR), 133 (25%) had nausea, 63 (12%) fainted, 35 (6%) developed hyperventilation, 9 (2%) had delayed syncope, and 9 (2%) developed hematoma. Arterial prick, nerve injury, cardiac arrest, and seizures were not observed. Donors aged less than < 30 years and weighing < 70 kg were significantly associated with VVR, hyperventilation, and nausea (p < 0.005). Undergraduates and Urdu speaking donors also had a significant association with fainting and nausea, respectively (p < 0.05).  .

CONCLUSION

The prevalence of adverse events was low at our tertiary center. A VVR was the predominant adverse reaction and was associated with age and weight. Our study highlights the importance of these parameters in the donation process. A well-trained and experienced phlebotomist and pre-evaluation counseling of blood donors could further minimize the adverse reactions.

Analysis of adverse events and predisposing factors in voluntary and replacement whole blood donors: A study from north India

BACKGROUND

Lack of awareness and community motivation, compounded with fragmented blood transfusion services in our country, Often leads to shortage of blood. Donor recruitment and retention are essential for ensuring adequate blood supply. However, adverse events (AEs) in donors have a negative impact on donor return.

AIMS AND OBJECTIVES

The present study was aimed to assess the frequency of AEs in whole blood donors and analyze the predisposing factors for AEs.

MATERIAL AND METHODS

The study was conducted on allogeneic whole blood donors over a period of 14 months, i.e., from January 2002 to February 2003. A total of 37,896 donors were monitored for any AEs: 22587 (59.6%) were voluntary donors (VD) and 15,309 (40.4%) were replacement donors (RD).

RESULTS

Overall reaction rate was 2.5% with vasovagal reactions constituting 63.5% and hematomas 35.0% of all reactions. Vasovagal reactions showed a significant association with young age, lower weight, first time donation status, female gender, and nature of blood donation camps. Amongst male donors, RDs had more reactions (P=0.03) than VDs. Majority of donors (85%) with vasovagal reactions admitted to some fear or anxiety prior to donation. Hematoma formation occurred significantly more when less trained staff performed phlebotomy.

CONCLUSION

Donor safety is an essential prerequisite to increase voluntary blood donation. AE analysis helps in identifying the blood donors at risk of donor reactions and adopting appropriate donor motivational strategies, pre-donation counseling, and care during and after donation.

Simple standing test predicts and water ingestion prevents vasovagal reaction in the high-risk blood donors

BACKGROUND

One of the serious complications of blood donation is vasovagal reaction (VVR) with syncope. This study was performed to determine if the measurement of hemodynamic responses to standing before blood collection (BC) was useful to identify the high-risk donors for VVR and also examined the effect of 300 mL of water ingestion in the prevention of VVR.

STUDY DESIGN AND METHODS

Blood pressure and heart rate (HR) during 5 minutes of standing were examined before and after BC in 93 donors. Because HR increase of 6 of 7 donors who developed syncopal VVR during standing after BC was 15 beats per minute (bpm) or greater, those with HR increase of 15 bpm or greater were determined as high-risk donors (n = 31). In another group (n = 117), 45 donors were identified as high risk based on the HR response before BC (15 bpm). The effect of 300 mL of water ingestion 15 minutes before BC on hemodynamic responses to standing and the rate of VVR after BC were analyzed.

RESULTS

Water ingestion given to the high-risk donors of the second group reduced HR increase with standing before BC (-6.6 ± 13.6 bpm, p < 0.02 vs. HR increase before water ingestion) and significantly suppressed VVR rate (2 of 45 donors with high risk, 4.4%,p < 0.04 vs. the first group; 6 of 31 high-risk donors, 19.4%).

CONCLUSION

HR response to standing before BC may detect the high-risk donors for VVR. For the high-risk donors, 300 mL of water ingestion may be a simple and effective way of prevention against syncopal VVR.

Monitoring analgesia

Analgesia (pain relief) amnesia (loss of memory) and immobilisation are the three major components of anaesthesia. The perception of pain, and therefore, the need for analgesia, is individual, and the monitoring of analgesia is indirect and, in essence, of the moment. Under general anaesthesia, analgesia is continually influenced by external stimuli and the administration of analgesic drugs, and cannot be really separated from anaesthesia: the interaction between analgesia and anaesthesia is inescapable. Autonomic reactions, such as tachycardia, hypertension, sweating and lacrimation, although non-specific, are always regarded as signs of nociception or inadequate analgesia. Autonomic monitoring techniques, such as the analysis of heart rate variability, laser Doppler flowmetry, phlethysmographically derived indices and the pupillary light reflex, may help to quantitate reactions of the autonomic nervous system. For the past few years, automated electroencephalographic analysis has been of great interest in monitoring anaesthesia and could be useful in adapting the peroperative administration of opioids. A range of information collected from the electroencephalogram, haemodynamic readings and pulse plethysmography might be necessary for monitoring the level of nociception during anaesthesia. Information theory, multimodal monitoring, and signal processing and integration are the basis of future monitoring.

Human autonomic responses to blood donation

In order to characterize autonomic responses to acute volume loss, supine ECG, blood pressure (BP) and uncalibrated breathing signal (UBS) recordings were taken before and after blood donation in 48 healthy volunteers. Time and frequency domain parameters of RR interval (RRI), BP and UBS variability were determined. Baroreflex gain was calculated by the technique of the spontaneous sequences and cross-spectral analysis. The systolic (SAP), diastolic (DAP) and mean BP (MAP) increased after the blood withdrawal. The central frequency of breathing and mean heart rate did not change. RRI variability increased in low frequency band (LF), tended to decrease in high frequency band (HF). Systolic BP variability increased in both frequency bands, but was statistically significant only in the high frequency band. Diastolic BP power increased in both frequencies. From the different baroreflex gain estimates, up sequence BRS and HF alpha index decreased significantly. The phase angle between RRI and systolic blood pressure powers in LF band did not change (-58 +/- 24 degrees and -54 +/- 26 degrees ). In the high frequency range, the phase became more negative (-1 +/- 29 degrees and -17 +/- 32 degrees, p = 0.001). The withdrawal of 350-400 ml blood in 5 min resulted in sympathetic activation, which was reflected in increased systolic, diastolic and mean BP. The increased BP oscillation was a sensitive marker of the minor volume depletion. This was coupled by increased RRI oscillation via baroreflex mechanisms in the LF band. Changes in the RRI and BP oscillations in the HF band showed no similar coupling. That points to the fact that RRI oscillations in this band should not be explained entirely by baroreflex mechanisms. Vagal withdrawal was reflected in decreased root mean square of successive differences (RMSSD), decreased HF RRI power and decreased up sequence BRS.

The role of disgust in faintness elicited by blood and injection stimuli

To examine the role of disgust in blood-injection fear and faintness, 79 individuals high and low in disgust and distressed either more by blood or injections were exposed to both a blood slide and a needle slide. Self-reported faintness and systolic and diastolic blood pressure were measured. High disgust individuals reported more faintness to both slides, but those who were more distressed by blood reported more faintness to the blood slide and those who were more distressed by needles reported more fear to the needle slide. Both systolic and diastolic blood pressure assessments manifested a diphasic response. The diphasic response pattern was most evident among the high disgust subjects, who were more distressed by blood than injections. Results are discussed in terms of the relevance of disgust in the etiology of fear and faintness in blood-injury phobia.

Predicting future blood donor returns: past behavior, intentions, and observer effects

A prospective design was used to explore the efficacy of 6 factors (e.g., intentions) to predict the number of future blood donations in an initial sample of 630 blood donors. Differential predictions are made for the roles of past behavior and intentions with respect to occasional (4 or fewer previous blood donations) and regular (5 or more previous blood donations) blood donors. Intentions were predictive for occasional donors, and past behavior was predictive for regular donors. Furthermore, for regular donors only, an inverted U-shaped curve explained the relationship between past behavior and future behavior. Finally, it is reported that observing others fainting produces a reduction in the number of future donations for occasional donors. The theoretical and practical implications of these findings are discussed.

Pathophysiologic basis for vasodepressor syncope

The current knowledge regarding the pathophysiologic basis of the vasodepressor response was reviewed. The balance of evidence indicates that the mechanoreceptor hypothesis seems unlikely to be the sole afferent alteration that leads to the vasodepressor response. Alternative afferent mechanisms should include neurohumoral mediated sympathoinhibition triggered by opioid mechanisms as well as impaired endothelial and NO responses to orthostatic stress in susceptible individuals. It is possible that impaired cardiovagal and sympathetic outflow control of arterial baroreceptors is enhanced by the aforementioned mechanisms. The role of central sympathoinhibition and vagal excitation triggered directly from pathways within the temporal lobe or triggered by alterations in regional cerebral blood flow should be considered as potential alternative mechanisms. Efferent autonomic outflow during vasodepressor syncope include sympathetic neural outflow withdrawal in addition to activation of parasympathetic outflow to the heart and abdominal viscera. Further human research is needed to understand the underlying mechanisms that result in the described neural and vascular responses.

Donor reactions and injuries from whole blood donation

In this review of common and uncommon donor reactions and injuries, donation-associated deaths were found to be extremely rare and generally thought to be coincidental; the rate of coincidental deaths was less than what would be expected based on life insurance tables. Vasovagal reactions, hematomas/bruises, and history of irritation or allergic reaction to adhesive tape or skin preparations are observed daily in a busy blood collection center. Syncopal vasovagal reactions sometimes resemble shock, but unlike shock, they reverse themselves and do not cause death. Through good management, a blood donor organization can minimize the incidence of syncope. Accidental arterial venipuncture is very uncommon (1 in 100,000), and donors with arterial punctures do well if pressure is applied for an extended period of time. Rarely, a pseudoaneurysm results, and this requires surgery. AV fistulas and compartment syndromes can also occur, but these are extremely rare; most experienced blood center physicians have never observed a case. Neurologic needle injuries occur approximately once in every 6,300 donations. Although neurologic needle injury complaints are usually received within 10 days of blood donation, 10% of the injured donors may complain weeks to months later. Most donors with needle injuries recover within a month and many within a day or two, but approximately 30% will have a recovery period of greater than 1 month and an occasional case may exceed 6 months. Donors with neurologic needle injuries generally have a full recovery, even when the recovery period may be extended. Thrombophlebitis has a low incidence (1 in 50,000 to 1 in 100,000), and infection at the phlebotomy site is rare. Both are easily treated and have little impact on the donor's health.