The effects of fentanyl on arterial pressure and heart rate increases during laryngoscopy and intubation were studied in 45 normotensive, surgical patients, who were randomly allocated to three groups receiving 2 or 6 micrograms/kg of fentanyl or saline in a double-blind fashion before anaesthetic induction with thiopental. Fentanyl supplementation with 2 micrograms/kg significantly attenuated the arterial pressure and heart rate increases during laryngoscopy and intubation, and fentanyl, 6 micrograms/kg, completely abolished these responses. Moreover, fentanyl given during the induction decreased the amount of fentanyl needed during the operation. Respiratory depression was not observed during recovery.

Attenuation of the circulatory response to laryngoscopy and intubation by fentanyl.

Synopsis: Pentazocine2, the N-allyl derivative of the narcotic analgesic phenazocine, is a strong analgesic with weak narcotic antagonist activity. It is advocated for the relief of moderate to severe pain. Pentazocine has a low abuse potential and is not controlled by narcotic regulations. Therapeutic trials comparing pentazocine with other strong analgesics have shown it to possess a strong analgesic effect when given intramuscularly and a lesser analgesic effect when administered orally at a dose of 50 mg. There is evidence that a greater analgesic effect can be obtained with an oral dose of 100 mg. Pentazocine produces side-effects similar to those associated with the morphine-like analgesics, and as with these analgesics the effects are exaggerated in ambulatory patients. Unlike the narcotic antagonist nalorphine, pentazocine produces only occasional subjective psychotomimetic effects at usual therapeutic doses.

Pentazocine: A Review of Its Pharmacological Properties, Therapeutic Efficacy and Dependence Liability

Sedation and analgesia is used primarily in the intensive care unit (ICU) to limit the stress response to critical illness, provide anxiolysis, improve ventilatory support, and facilitate adequate ICU care. However, in the neurotrauma ICU there are many other reasons for the use of these agents. The primary aim is to prevent secondary cerebral damage by maintaining adequate cerebral perfusion pressures. This is accomplished in several different ways. Controlling intracranial pressure (ICP) and maintaining an adequate mean arterial pressure (MAP) is at the cornerstone of this management. Lowering the metabolic demands of the brain is also an important consideration as a treatment strategy. Analgesic and sedative agents are utilized to prevent undesirable increases in ICP and to lower cerebral metabolic demands. Concerns surrounding the use of these agents include time to awakening after discontinuation, effect on the cerebrovasculature, and the effect on patient outcome. There are many different pharmacological agents available, each with their distinct advantages and disadvantages. The purpose of this review is to evaluate the pharmacokinetic and pharmacological effects of each of these agents when used in neurotrauma patients.

Use of sedative and analgesic agents in neurotrauma patients: Effects on cerebral physiology

Cardiovascular effects of high dose opioid together with low dose inhalant were compared with inhalant alone to determine whether opioid/inhalant techniques were less depressant on the cardiovascular system. The effects of positive pressure ventilation and increasing heart rate to a more physiological level were also studied. Cardiovascular measurements recorded during administration of enflurane at 1.3 minimum alveolar concentration (MAC; 2.89 +/- 0.02%) to spontaneously breathing dogs (time 1) and during controlled ventilation [arterial carbon dioxide tension at 40 +/- 3 mmHg (time 2)] were similar. At time 2, mixed venous oxygen tension and arterial and mixed venous carbon dioxide tensions were significantly decreased, while arterial and mixed venous pH were significantly increased compared to measurements at time 1. After administration of fentanyl to achieve plasma fentanyl concentration of 71.7 +/- 14.4 ng/mL and reduction of enflurane concentration to yield 1.3 MAC multiple (0.99 +/- 0.01%), heart rate significantly decreased, while mean arterial pressure, central venous pressure, stroke index, and systemic vascular resistance index increased compared to measurements taken at times 1 and 2. Pulmonary arterial occlusion pressure was significantly increased compared to measurements taken at time 2. After administration of atropine until heart rate was 93 +/- 5 beats/min (plasma fentanyl concentration 64.5 +/- 13.5 ng/mL) heart rate, mean arterial pressure, cardiac index, oxygen delivery index, and venous admixture increased significantly compared to values obtained at all other times.(ABSTRACT TRUNCATED AT 250 WORDS)

The cardiovascular sparing effect of fentanyl and atropine, administered to enflurane anesthetized dogs.

To investigate cardiovascular effects in 32 ventilated neonates, given either pancuronium or pethidine, computer based data were analysed for five minutes preceding and for 20 minutes after administration of the drugs. Heart rate and direct mean arterial pressure remained unchanged but arterial pressure variability decreased with each drug.

https://adc.bmj.com/content/archdischild/62/11/1179.full.pdf

Effect of pancuronium and pethidine on heart rate and blood pressure in ventilated infants.

SUMMARY The cardiovascular responses to five sequential intravenous injections of pentazocine (5×0.6 mg/kg), fentanyl (5×0.001 mg/kg) and pethidine (5×1.0 mg/kg) were assessed in conscious and anaesthetized subjects. In conscious volunteers pentazocine raised the systolic pressure by 30 per cent. Pentazocine and pethidine raised the diastolic pressure by 10 per cent and the heart rate by 15 per cent; with pethidine the increases were not sustained but tended to fluctuate. Fentanyl did not affect the pressure or heart rate. In anaesthetized patients, all three analgesics caused a 20–25 per cent fall in blood pressure and heart rate, fluctuations in pressures occurring in the pentazocine and pethidine group. No changes of e.c.g. pattern were observed. Pentazocine, pethidine and fentanyl thus exert different haemodynamic effects in conscious and anaesthetized subjects.

S. Takki

Papers

A comparison of the circulatory effects in man of the analgesics fentanyl, pentazocine and pethidine

A comparison of the circulatory effects in man of the analgesics fentanyl, pentazocine and pethidine