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Biomedical subjects

J J Pandit

Publications and source records attributed to J J Pandit.

At least 37 records · Page 2Linked to original sources
PubMed2002

The variable effect of low-dose volatile anaesthetics on the acute ventilatory response to hypoxia in humans: a quantitative review.

The purpose of this study was to review published studies (identified by a Medline-assisted search) on the effect of < or = 0.2 minimal alveolar concentration (MAC) halothane, isoflurane, enflurane and sevoflurane on the acute hypoxic ventilatory response in healthy subjects. Each article was examined for the anaesthetic agent, speed of hypoxic stimulus, background carbon dioxide and subject stimulation (audiovisual or painful). Analysis of variance was used to assess the significance of the influence of each of these factors on the standardised hypoxic response (the acute hypoxic ventilatory response in l.min(-1) in the presence of anaesthetic, expressed as a fraction of the response without anaesthetic). There were 37 separate studies within 21 published articles. The main factor influencing standardised hypoxic response was anaesthetic agent (p < 0.002). A second influential factor was subject stimulation (p < 0.014), but the interaction term of agent and stimulation was also significant (p < 0.039), suggesting that the influence of stimulation varied with the agent used. Speed of hypoxia and background carbon dioxide had no influence. In contrast to previous authors' assertions that study conditions have a major impact on the acute ventilatory response to hypoxia, this review suggests that the main determinant is simply the anaesthetic agent used. The review also highlights important gaps in the research literature, which may direct future research in this field. In particular, it would seem important to investigate the influence of arousal when different anaesthetic agents are used.

Analysis of Variance↗
PubMed2002

Bispectral index-guided management of anaesthesia in permanent vegetative state.

A patient in a permanent vegetative state required general anaesthesia for dental surgery. Because of the uncertainties involved in the appropriate monitoring and assessment of the conscious level of patients in a permanent vegetative state, it was decided to use the bispectral index to help guide the anaesthetic depth during surgery. We found that the bispectral index profile during anaesthesia and surgery was similar to that of a normal subject. The findings raise the possibility that patients in permanent vegetative states might sense noxious stimuli at a cortical level.

Anesthesia, Dental↗
PubMed2000

A comparison of superficial versus combined (superficial and deep) cervical plexus block for carotid endarterectomy: a prospective, randomized study.

Carotid endarterectomy may be performed by using cervical plexus blockade with local anesthetic supplementation by the surgeon during surgery. Most practitioners use either a superficial cervical plexus block or a combined (superficial and deep) block, but it is unclear which offers the best operative conditions or greatest patient satisfaction. We compared the two techniques in patients undergoing carotid endarterectomy. Forty patients undergoing carotid endarterectomy were randomized to receive either a superficial or a combined cervical plexus block. Bupivacaine 0.375% to a total dose of 1.4 mg/kg was used. The main outcome measure was the amount of supplemental lidocaine 1% used by the surgeon. Subsidiary outcome measures were postoperative pain score, sedative and analgesic requirements before and during surgery, and postoperative analgesic requirements. Median supplemental lidocaine requirements were 100 mg (range 30-180 mg) in the superficial block group and 115 mg (range 30-250 mg) in the combined block group. These differences were not statistically significant (Mann-Whitney U-test). There was no significant difference in the number of patients needing postoperative analgesia between the groups (11 of 20 in the deep block group versus 8 of 20 in the superficial block group) in the 24 h after surgery. The median time to first analgesia in the superficial block group was 150 min, more than in the combined block group (median time 45 min) but this difference, although large, was not statistically significant (Mann-Whitney U-test). We found no significant differences between the anesthetic techniques studied. All patients reported satisfaction with the techniques.

Acetaminophen↗
PubMed1999

Effects of subanaesthetic sevoflurane on ventilation. 1: Response to acute and sustained hypercapnia in humans.

We have determined the influence of 0.1 minimum alveolar concentration (MAC) of sevoflurane on ventilation, the acute ventilatory response to a step change in end-tidal carbon dioxide and the ventilatory response to sustained hypercapnia in 10 healthy adult volunteers. Subjects undertook a preliminary 10-min period of breathing air without sevoflurane to determine their normal ventilation and natural end-tidal PCO2. This 10-min period was repeated while breathing 0.1 MAC of sevoflurane. Subjects then undertook two procedures: end-tidal PO2 was maintained at 13.3 kPa and end-tidal PCO2 at 1.3 kPa above the subject's normal value for 30 min of data collection, first with and then without 0.1 MAC of sevoflurane. A dynamic end-tidal forcing system was used to generate these gas profiles. Sevoflurane did not significantly change ventilation: 10.1 (SEM 1.0) litre min-1 without sevoflurane, 9.6 (0.9) litre min-1 with sevoflurane. The response to acute hypercapnia was also unchanged: mean carbon dioxide response slopes were 20.2 (2.7) litre min-1 kPa-1 without sevoflurane and 18.8 (2.7) litre min-1 kPa-1 with sevoflurane. Sustained hypercapnia caused a significant gradual increase in ventilation and tidal volume over time and significant gradual reduction in inspiratory and expiratory times. Sevoflurane did not affect these trends during sustained hypercapnia. These results suggest that 0.1 MAC of sevoflurane does not significantly affect the acute ventilatory response to hypercapnia and does not modify the progressive changes in ventilation and pattern of breathing that occur with sustained hypercapnia.

Acute Disease↗
PubMed1999

Effects of subanaesthetic sevoflurane on ventilation. 2: Response to acute and sustained hypoxia in humans.

We have determined the influence of 0.1 minimum alveolar concentration (MAC) of sevoflurane on the acute ventilatory response to hypoxia (AHVR), hypoxic ventilatory decline (HVD) and the magnitude of the rapid decline in ventilation on relief of sustained hypoxia (the off-response) in eight healthy adult volunteers. The following design was used with and without 0.1 MAC of sevoflurane: end-tidal PO2 was maintained at 13.3 kPa for 5 min, at 7.9 kPa for 20 min and at 13.3 kPa for 5 min. End-tidal PCO2 was held constant throughout at 1.3 kPa above the subject's normal value. A dynamic end-tidal forcing system was used to generate these gas changes. Sevoflurane reduced AHVR from 14.5 (SEM 1.2) to 11.6 (1.6) litre min-1, and the off-response at cessation of hypoxia from 7.1 (1.1) to 6.3 (1.4) litre min-1. The magnitude of HVD was slightly increased by sevoflurane from 8.2 (1.1) to 10.6 (2.8) litre min-1. None of these changes was significant (ANOVA). These results suggest that 0.1 MAC of sevoflurane had very little effect on the AHVR, and that it did not markedly alter the processes underlying HVD during sustained hypoxia.

Acute Disease↗