Philippe T. Gilchrist

The effects of blood-draw and injection stimuli on the vasovagal response

Vasovagal reactions (VVR) are common, complicating and deterring people from various medical procedures. A recent perspective (R. R. Diehl, ) suggests that VVR developed from the adaptive process of hemorrhagic fainting, perhaps as a means of preparing for anticipated blood loss. The primary goal of this study was to compare vasovagal symptoms during intravenous-injection and blood-draw videos. Sixty-two young adults watched the videos. Vasovagal symptoms were assessed with self-report, blood pressure, and heart rate variability. As predicted, participants reported more vasovagal symptoms and anxiety following the blood-draw video. Sympathetic nervous system activity (low- to high-frequency ratio) decreased during both videos but significantly more during the blood-draw video, although this could be reversed by the Applied Tension technique. Results are discussed in terms of the relevance of specific stimuli and emotions in VVR.

Relation between perceived blood loss and vasovagal symptoms in blood donors

Introduction/ResultsThis study examined whether a belief of significant blood loss may be associated with vasovagal symptoms, irrespective of actual blood loss. Individual differences in vasovagal symptoms among blood donors who had an equivalent amount of blood withdrawn were significantly associated with their rating of perceived blood loss.ConclusionThe anticipation or belief of blood loss, and perhaps more remotely associated ideas, may trigger processes similar to those induced by actual hemorrhage though further research is required to address other possibilities such as the inflation of ratings by vasovagal symptoms.

The vasovagal response during confrontation with blood-injury-injection stimuli: The role of perceived control ☆

The vasovagal response (VVR) is a common medical problem, complicating and deterring people from various procedures. It is an unusual stress response given the widespread decreases in physiological activity. Nevertheless, VVR involves processes similar to those observed during episodes of strong emotions and pain. We hypothesized that heightened perceived control would reduce symptoms of VVR. Eighty-two young adults were randomly assigned to perceived control or no perceived control conditions during exposure to a stimulus video of a mitral valve surgery, known to trigger VVR in non-medical personnel. Perceived control was manipulated by allowing some participants to specify a break time, though all received equivalent breaks. Outcomes included subjective symptoms of VVR, anxiety, blood pressure, heart rate, and other measures derived from impedance cardiography. Compared to participants with perceived control, participants with no perceived control reported significantly more vasovagal symptoms and anxiety, and experienced lower stroke volume, cardiac output, and diastolic blood pressure. Participants who were more fearful of blood were more likely to benefit from perceived control in several measures. Perceived control appears to reduce vasovagal symptoms. Results are discussed in terms of cognition and emotion in VVR.

Sense of impending doom: Inhibitory activity in waiting blood donors who subsequently experience vasovagal symptoms

This study examined autonomic and hemodynamic processes associated with the development of naturally occurring vasovagal responses. Data from a study assessing the physiological correlates of an intervention to reduce vasovagal responses in blood donors were examined (Ditto et al., 2009). Ninety-eight participants were assigned randomly to groups that either practiced applied tension or not. Dependent variables included ratings of vasovagal symptoms, heart rate, blood pressure, and other parameters derived from ambulatory impedance cardiography. Participants who subsequently experienced vasovagal symptoms had a lower ratio between low and high frequency components (LF/HF HRV) of heart rate variability (HRV) before blood donation, suggesting lower sympathetic nervous system activity. They also showed sharper decreases in total peripheral resistance and lower respiration rates. The results suggest that vasovagal reactions that begin during anticipation of a medical procedure may be characterized by an inhibitory process from the outset and do not support the belief that reactions follow a diphasic pattern.

The effects of leg crossing and applied tension on blood donor return.

Repeated isometric muscle tension (applied tension) during blood donation reduces vasovagal symptoms in many donors. Experiencing vasovagal symptoms has been found to reduce blood donor return. However, does practicing applied tension improve blood donor return? Follow‐up results from a randomized controlled trial are presented.

The paradox of moral cleansing: When physical cleansing leads to increased contamination concerns

BACKGROUND AND OBJECTIVES Moral threats, including threats to moral self-worth, have been associated with contamination concerns. Paradoxically, although self-cleansing provides temporary relief, it can worsen feelings of contamination. Self-affirmation might be an effective strategy, especially following obsessive type cognitions (e.g., responsibility beliefs) when moral threats are reactivated. METHODS In Experiment 1, participants recalled an immoral deed and then self-cleansed (using a hand-wipe), completed a control task, or self-affirmed. Contamination concerns were subsequently measured by a washing task. In Experiment 2, the same procedure was used but obsessive-type cognitions were activated by asking participants a series of questions about obsessive beliefs. RESULTS As expected, relative to the control condition, both self-affirmation and self-cleansing resulted in less subsequent repeated washing behaviour in Experiment 1. In Experiment 2, when the immoral recall was followed by activation of obsessive-type cognitions, self-cleansing led to more guilt and repeated washing than self-affirmation and control. Rather than alleviating feelings of contamination, physical self-cleansing led to more contamination concerns and guilt when in the context of activated obsessive-type cognitions, possibly because it paradoxically makes (moral) cleanliness goals salient. LIMITATIONS Future research needs to test clinical populations, for whom contamination concerns are all the more central. CONCLUSIONS This research provides further evidence of the influence of moral threat in contamination concerns, and the limits of moral cleansing. Self-affirmation resulted in less contamination concerns under both a neutral condition and activated obsessive type cognitions.

Respiratory and hemodynamic contributions to emotion-related pre-syncopal vasovagal symptoms

Vasovagal reactions are conventionally understood as resulting from systemic changes in cardiovascular activity; however, there exists a complementary perspective focused on specific changes in cerebral vasoconstriction associated with hyperventilation-induced hypocapnia. The present study investigated the role of cardiovascular and respiratory activity in self-reported pre-syncopal vasovagal reactions to a surgery video in a sample of 49 healthy women. Participants who indicated more previous real-life episodes of dizziness reported experiencing significantly more symptoms in the laboratory consistent with a vasovagal response. They also showed lower total peripheral resistance and higher pre-ejection period in general, suggesting lower sympathetic nervous system activity. Significant decreases in end-tidal carbon dioxide (PETCO2) occurred during the surgery video among susceptible participants, without significant increases in respiration rate. Further, participants who experienced reductions from the neutral video in PETCO2, systolic blood pressure, or both, reported vasovagal symptoms during the surgery video. The results suggest that patterns of respiration associated with decreases in PETCO2 may contribute to vasovagal symptoms reported in non-clinical groups as well as those with blood-injection-injury phobia and are associated with susceptibility to dizziness.