Time to consider the role of rationalisation in health psychology.

OBJECTIVE: The objective of this study was to determine the interaction between psychological factors, belief systems, and engagement around public health initiatives. STUDY DESIGN: We conducted a longitudinal observational study, utilising convenience sampling to examine illness-related perception in the immediate and medium-term stages of the first wave of the SARS-CoV-2 pandemic in the UK. METHODS: Weekly questionnaires assessed our primary measure, illness-related perception, using The Health Anxiety Inventory. Other psychological measures included apathy, loneliness, depersonalisation, state anxiety, trait anxiety as well as personality traits. Multiple regressions were performed to determine which psychological factors predicted the variance of health anxiety every week using the enter method. RESULTS: A combination of psychological variables that varied over time and were modulated by external events predicted the evolution of illness-related perception and associated aversion to perceived threat. CONCLUSION: Our findings highlight how in the face of a public health crisis, psychological factors play a determining role in the synthesis of beliefs as well as guiding human behaviour.

Right hemisphere dominance directly predicts both baseline V1 cortical excitability and the degree of top-down modulation exerted over low-level brain structures.

Right hemisphere dominance for visuo-spatial attention is characteristically observed in most right-handed individuals. This dominance has been attributed to both an anatomically larger right fronto-parietal network and the existence of asymmetric parietal interhemispheric connections. Previously it has been demonstrated that interhemispheric conflict, which induces left hemisphere inhibition, results in the modulation of both (i) the excitability of the early visual cortex (V1) and (ii) the brainstem-mediated vestibular-ocular reflex (VOR) via top-down control mechanisms. However to date, it remains unknown whether the degree of an individual's right hemisphere dominance for visuospatial function can influence, (i) the baseline excitability of the visual cortex and (ii) the extent to which the right hemisphere can exert top-down modulation. We directly tested this by correlating line bisection error (or pseudoneglect), taken as a measure of right hemisphere dominance, with both (i) visual cortical excitability measured using phosphene perception elicited via single-pulse occipital trans-cranial magnetic stimulation (TMS) and (ii) the degree of trans-cranial direct current stimulation (tDCS)-mediated VOR suppression, following left hemisphere inhibition. We found that those individuals with greater right hemisphere dominance had a less excitable early visual cortex at baseline and demonstrated a greater degree of vestibular nystagmus suppression following left hemisphere cathodal tDCS. To conclude, our results provide the first demonstration that individual differences in right hemisphere dominance can directly predict both the baseline excitability of low-level brain structures and the degree of top-down modulation exerted over them.

Critique of the Dornier HM3 lithotripter as a clinical algesimeter.

The power and nociceptive intensity of shock waves generated by the Dornier HM3 extracorporeal shock wave lithotripter (ESWL) are voltage dependent and suited to algesimetry in a controllable voltage range of 8-30 kV. Fidelity of the HM3 as an algesimeter was tested by: (1) In vitro measurements of shock pressure at voltages between 14 and 30 kV were recorded by a force transducer at the point of clinical focus. (2) Unanaesthetized volunteer (n = 5) assessment and VAS pain scores of shocks in the range of 10-24 kV, yielding highly significant correlations between blinded randomized shock voltage (r = 0.88), and VAS scores (r = 0.84). (3) Voltage-tolerance curves generated from 33 ASA class 1 or 2 patients undergoing ESWL treatment under epidural analgesia with 0.125% bupivacaine, fortified with a bolus epidural dose of 100 micrograms fentanyl if pain arose during treatment. Voltage tolerance was increased by 50% after an epidural bolus of 100 micrograms fentanyl (P less than 0.001). The respiratory consequences of epidural fentanyl were assessed by changes of respiratory rate and rhythm recorded from capnographic tracings of expired carbon dioxide. This study indicates that the Dornier HM3 system provides a valuable opportunity to conduct precise, quantitative measurements of induced deep truncal pain, as well as the effectiveness and respiratory cost of analgesic interventions directly applicable to the safe management of acute pain.

Influence of Dornier HM3 system on respiration during extracorporeal shock-wave lithotripsy.

Patients undergoing extracorporeal shock-wave lithotripsy (ESWL) for renal stones in the Dornier HM3 apparatus are immersed to the clavicles in water and anchored by abdominal and leg restraining straps. The respiratory effects of this system and sedation with midazolam were studied in 70 awake patients anesthetized with epidural blockade. On immersion, surface abdominal pressure and respiratory frequency (f) increased. Tidal volume (VT) and arterial saturation (SaO2) decreased. After intravenous midazolam 0.045 mg/kg body weight, VT decreased further to 35% below pre-immersion values and stone excursions measured by fluoroscopy diminished by more than 50%; reduction of VT and stone excursions were linearly correlated (R = 0.45). SaO2 declined sharply to 6.1% (range -1.5-13.8%) below pre-immersion values, whereas end-tidal CO2 (PETCO2) increased more slowly and f remained above the pre-immersion rate. In three patients, SaO2 decreased to below 85% but was rapidly restored to 98-100% by oxygen administration. The respiratory effects of sedative drugs are exaggerated by the Dornier HM3 system, and continuous monitoring of gas exchange and appropriate oxygen administration are recommended in patients receiving regional anesthesia and sedation.

131I-metaiodobenzylguanidine (mIBG) for bronchial oat cell cancer and melanoma detection?

The neuroendocrine features of bronchial oat cell carcinoma and melanoma indicate the possibility of positive imaging by means of radiolabelled metaiodobenzylguanidine. However, only four out of seven patients with bronchial oat cell carcinoma and three out of seven with melanoma were correctly diagnosed. Only false negative and no false positive results were obtained. The findings demonstrate a limited diagnostic value of the tracer in the tumor types examined.

Relationship between posttetanic count and response to carinal stimulation during vecuronium-induced neuromuscular blockade.

The correlation between degree of peripheral neuromuscular blockade and response to carinal stimulation was evaluated in two groups of 25 patients: one group was anaesthetized with thiopental, N2O and halothane, and the other group received thiopental, N2O and fentanyl. The degree of peripheral blockade was evaluated using train-of-four (TOF) and posttetanic twitch (PTC) stimulation of the ulnar nerve. The degree of diaphragmatic paralysis was evaluated indirectly by stimulating the carina and observing the corresponding muscular response, which was graded as severe, mild or absent. During halothane anaesthesia a PTC of 0 always indicated that no response to carinal stimulation could be elicited. On the appearance of the first response to posttetanic twitch stimulation (PTC = 1), 2% of the patients showed a mild response to carinal stimulation. At the first response to TOF stimulation, 48% of the patients reacted with a mild response. During thiopental, N2O, fentanyl anaesthesia one of 25 patients showed a mild response to carinal stimulation at a PTC of 0. When PTC was 1, 20% of the patients reacted mildly to the stimulation. At the first response to TOF stimulation, 92% showed a response to carinal stimulation; 24% of these responses were severe, necessitating intervention. It is concluded that the TOF response elicited peripherally is a late sign of neuromuscular recovery of the diaphragm, and that the method of counting posttetanic twitches is superior to the TOF response in evaluating early recovery of this muscle. Further, to ensure total diaphragmatic paralysis, the neuromuscular blockade of the peripheral muscles should be so intense that no response to posttetanic twitch stimulation (PTC = 0) can be elicited.

Relationship of post-tetanic count and train-of-four response during intense neuromuscular blockade caused by atracurium.

Atracurium-induced intense neuromuscular blockade was evaluated in 60 randomly selected patients using the post-tetanic count (PTC) and train-of-four (TOF) methods. Thirty patients were anaesthetized with thiopentone, nitrous oxide and halothane, and 30 patients received thiopentone, nitrous oxide and fentanyl. In all patients, the response to post-tetanic single twitch stimulation appeared before the response to TOF stimulation, and a close correlation was found between the number of post-tetanic twitches (PTC) and the time interval between the PTC and the first detectable TOF response. A PTC of zero indicated that the time to first response to TOF stimulation was always more than 8 min. A PTC of 1 meant that the TOF response would appear in, on average, 9 min (95% confidence limits: 4-14 min). Halothane significantly prolonged the time from injection of atracurium to the first response to post-tetanic single twitch stimulation. It is concluded that the relationship between PTC and the time to first response to TOF nerve stimulation makes the PTC method a valuable supplement to TOF nerve stimulation for neuromuscular monitoring during clinical anaesthesia involving atracurium.

A new medium improves sampling for determination of platelet factor 4 in human plasma.

The determination of alpha-granule specific platelet proteins in human plasma is a valuable indicator of in-vivo release and platelet activation provided that an artificial in-vitro release during sampling can be avoided. A new sampling medium (M) has been compared with the commercially available ones for the sampling and the subsequent determination of platelet factor 4 and beta-thromboglobulin. M allows blood withdrawal at room temperature (22 degrees C) (3.49 +/- 0.7 ng/ml) without any difference to 4 degrees C (3.47 ng/ml) up to a 30 minutes sedimentation period. However, after 40 minutes there is a significant (p less than 0.01) increase, amounting at 22 degrees C (13.30 ng/ml) and at 4 degrees C 6.68 ng/ml. The addition of prostacyclin (PGI2) in-vitro as well as blood withdrawal from volunteers infused with PGI2 at a rate of 5 ng/kg/min did not alter the values of M-preserved samples, whereas in the commercially available ones, PGI2 caused a decrease. A comparison of radioimmunoassay and enzyme immunoassay exhibited no significant difference in the absolute values. Beta-thromboglobulin was assayed as control. The findings indicate M being optimal for the sampling of platelet factor 4, but not for other alpha-granule release products. Thus, there is again evidence, that the alpha-granule products are not released to an equal extent upon a certain stimulus. Furthermore, it seems likely, that various substances inhibit their liberation from the platelet to a differing extent.

Accidental cross-connexion of oxygen and nitrous oxide in an anaesthetic machine.

Oxygen and nitrous oxide pipes were cross-connected during the servicing of an anaesthetic machine. This resulted in the delivery of 100% nitrous oxide instead of 100% oxygen at the end of the operation. The patient fully recovered and was discharged on the 13th day.