Clinical Signs of Anesthesia

Cullen, David J.; Eger, Edmond I.; Stevens, Wendell C.; Smith, N. Ty; Cromwell, Thomas H.; Cullen, Bruce F.; Gregory, George; Bahlman, Steven H.; Dolan, William M.; Stoelting, Robert K.; Fourcade, Henry E.

doi:10.1097/00000542-197201000-00005

Cited by 73 publications

(26 citation statements)

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“…For example, firm skin pressure, visible light, manipulation of the limbs, sound, and low-frequency electrical stimulation (1 Hz or below) all fail to dilate the pupil during general anesthesia with volatile anesthetics at concentrations exceeding 60% of a standard dose (i.e., 1 minimum alveolar concentration) (13,14,17,21). Similarly, observation of the pupil during surgery affirms that painful stimuli are required to dilate the pupil except during emergence, profound hypotension, and/or light anesthesia (7,(13)(14)(15)(16).…”

Section: Discussionmentioning

confidence: 93%

Latency of pupillary reflex dilation during general anesthesia

Larson¹,

Berry²,

May³

et al. 2004

Journal of Applied Physiology

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of pupillary reflex dilation during general anesthesia. J Appl Physiol 97: 725-730, 2004; 10.1152/ japplphysiol.00098.2004.-Areas of insensibility produced by neuraxial anesthesia or peripheral nerve blocks can be detected during general anesthesia by failure of noxious stimulation to trigger pupillary reflex dilation. We examined the latency of pupillary reflex dilation and the effect of fentanyl on the latency of reflex dilation during anesthesia in nine volunteers. We hypothesized that the reflex was generated by slowly conducting C nociceptive fibers and would be significantly delayed if a distal dermatome (L 4) was stimulated compared with a proximal dermatome (C5). We also hypothesized that fentanyl would prolong the latency and alter the shape of the reflex. After induction of general anesthesia, pupillary reflex dilation was measured with an infrared pupillometer every 5 min after stimulations of the L 4 and C5 dermatomes. Fentanyl (3 g/kg) was then given intravenously. Pupillary reflex dilation latencies were calculated by examining each individual measurement. After 3 h, naloxone (400 g) was given intravenously; anesthesia was then discontinued. Pupillary reflex dilation had a long latency and consisted of distinct early and late phases. No differences were found between latencies of reflex dilation after simulation of L 4 and C5 dermatomes either before or after fentanyl administration. Fentanyl at high concentrations essentially eliminated pupillary reflex dilation; but over the 180-min observation period, first early and then late dilation returned. Fentanyl produced a small increase in the latency of the initial early dilation. We conclude that pupillary reflex dilation during anesthesia is not initiated by slowly conducting C fibers and that fentanyl depresses the reflex in a stereotypical manner. nociception; windup; pupil; opioids; sensory block PUPILLARY REFLEX DILATION (PRD) is a midbrain reflex that has been used clinically to define the extent of local anesthetic blockade during general anesthesia. Although the reflex peaks 1 min after the stimulus starts, a more prompt assessment of sensory blockade should be possible by examining the early portion of the reflex. Thus knowledge of the latency of PRD, and the factors that influence latency, is critical for a timely and reliable detection of the reflex, especially when the reflex magnitude has been attenuated by anesthetic adjuvants including opioids (14,19).Studies in anesthetized animals have shown that the reflex latency is ϳ350 ms (2, 23). The feline reflex proceeds from the nociceptor primarily via C-fiber transmission (8) to the spinal cord and then to the midbrain where norepinephrine-containing neurons are activated. These neurons then inhibit the pupilloconstrictor neurons, resulting in a passive dilation of the pupil (11).Although the reflex in anesthetized humans is thought to be similarly expressed (13, 28), preliminary evidence has shown that the latency of PRD in anesthetized humans is remarkably long and proceeds in two distin...

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Section: Discussionmentioning

confidence: 93%

Latency of pupillary reflex dilation during general anesthesia

Larson¹,

Berry²,

May³

et al. 2004

Journal of Applied Physiology

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“…Guedel described the use of the pupil as a guide to depth in ether anaesthesia, but these responses vary with individual anaesthetic agents (for example halothane tends to constrict the pupil whereas nitrous oxide and ether dilate the pupil), and with premedication (for example atropine produces pupillary dilation and opioids produce pupillary constriction). However, some generalizations can still be made; deep anaesthesia almost always produces an absence of eye movement, and reduces or abolishes the light response (Cullen et al, 1972). However, the response may not necessarily be due to the higher centres of the brain perceiving pain, since it has been noted that 'brain dead' organ donor patients can show haemodynamic changes in response to surgery (Wetzel et al, 1985), yet by definition there can be no conscious perception of pain.…”

Section: Autonomic Parametersmentioning

confidence: 99%

The assessment of depth of anaesthesia in animals and man

Whelan¹,

Flecknell²

1992

Lab Anim

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SummaryThe assessment of the depth of anaesthesia in man has received much attention in recent years, following a number of reports of people being aware during surgery. A range of different measures have been suggested for determining the adequacy of anaesthesia in man, but such a critical assessment is rarely applied to laboratory animals. This article describes the methods used to assess anaesthetic depth in both man and animals, and compares the relative states of knowledge about anaesthetic depth in animals and man.

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“…Thus, anesthetists solve the matter via measuring some other available factors such as blood pressure, heart rate and so on. In [12], Cullen showed that there is a plausible correlation between blood pressure and anesthetic dose. In other words, gaining a sufficient depth of anesthesia is feasible through controlling the blood pressure related factors such as the MAP (Mean Arterial Pressure which is measured in Fig.…”

Section: Lemma 23mentioning

confidence: 99%

Fuzzy semi-numbers and a distance on them with a case study in medicine

2018

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In this paper, we present the novel concept of fuzzy semi-numbers. Then, a method for assigning distance between every pair of fuzzy semi-numbers is given. Moreover, it is shown that this distance is a metric on the set of all trapezoidal fuzzy semi-numbers with the same height and is a pseudo-metric on the set of all fuzzy semi-numbers. Also, by utilizing this distance, we propose an approximation of a fuzzy semi-number with given height and apply this approximation method in a medical case study.

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Clinical Signs of Anesthesia

Cited by 73 publications

References 0 publications

Latency of pupillary reflex dilation during general anesthesia

Latency of pupillary reflex dilation during general anesthesia

The assessment of depth of anaesthesia in animals and man

Fuzzy semi-numbers and a distance on them with a case study in medicine

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