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Biomedical subjects

R R Bartkowski

Publications and source records attributed to R R Bartkowski.

23 records · Page 2Linked to original sources
PubMed1983

Pancuronium, unlike other nondepolarizing relaxants, retains potency at hypothermia.

The authors studied the pharmacodynamics of four nondepolarising relaxants, d-tubocurarine (dTC), pancuronium, metocurine, and gallamine, at 25 degrees C, 31 degrees C, and 37 degrees C. The rat phrenic nerve-hemidiaphragm preparation with vascular perfusion was used for these investigations. For each drug at each temperature, a dose-response curve for twitch depression was constructed. ED50 values were calculated using probit-log dose regression. dTC, metocurine, and gallamine each demonstrated a near twofold increase in ED50 at 25 degrees C compared with 37 degrees C. No such relationship was apparent with pancuronium. In addition, the slopes of the dose-response curves were analyzed for effects due to temperature or drug. Slopes were not influenced by temperature; however, the slopes for metocurine and dTC were lower than those for pancuronium and gallamine. The authors conclude that in the rat, pancuronium retains potency at hypothermia, whereas the other relaxants decrease potency. In addition, metocurine and dTC exhibit less steep dose-response curves under these experimental conditions.

Animals↗
PubMed1983

Recovery of neuromuscular function in the perfused rat diaphragm after succinylcholine and pancuronium blockade.

The recovery of the rat diaphragm from neuromuscular blockade was studied in order to separate the contributions of drug binding and tissue washout. The in vitro rat diaphragm preparation was perfused with a cholinesterase-free solution via the phrenic vein and stimulated electrically via the phrenic nerve. Muscle paralysis was induced by infusion of a depolarizing blocker succinylcholine or by the nondepolarizing blocker pancuronium. The time for recovery from 25-75% recovery averaged 1.0 +/- 0.1 min for pancuronium and 0.8 +/- 0.1 min for succinylcholine at the fast (1.9 ml/min) perfusion rate. This was prolonged to 2.0 +/- 0.3 min for pancuronium and 1.4 +/- 0.1 min for succinylcholine at the slower (0.76 ml/min) rate. More sensitive paired tests of recovery utilizing recovery time and rate demonstrated no drug difference in three comparisons and a 44% longer recovery time for pancuronium only at the lower perfusion rate. In general, recovery times were similar for both drugs. The rapid recovery from pancuronium blockade in this mammalian system as perfusion rate was increased suggests that recovery from this drug is not impaired by drug binding but is strongly dependent on organ perfusion.

Animals↗
PubMed1982

Low-dose fentanyl blunts circulatory responses to tracheal intubation.

The effect of fentanyl, 8 micrograms/kg, used as an adjunct to thiopental for induction of anesthesia, on the circulatory response to tracheal intubation was investigated in 36 patients undergoing major vascular surgery. Patients were randomly assigned to receive either thiopental, 6 mg/kg, alone (N = 18), or thiopental, 3 mg/kg, along with fentanyl, 8 micrograms/kg (N = 18), for induction of anesthesia. The electrocardiogram, arterial pressure, pulmonary capillary wedge pressure, cardiac output, and central venous pressure were measured during induction of anesthesia, laryngoscopy, and intubation. Mean arterial blood pressure increased more following intubation in patients given thiopental than in patients given fentanyl-thiopental, reaching a peak value of 144 +/- 4 torr in patients receiving thiopental only, compared with 108 +/- 6 torr in those receiving fentanyl and thiopental (p less than 0.0001). Increases in systolic blood pressure, diastolic blood pressure, and pulmonary capillary wedge pressure with intubation were also significantly greater following administration of thiopental than following fentanyl-thiopental. Doses of fentanyl that are low enough to cause little postoperative respiratory depression significantly blunt postintubation hypertension when used as an adjunct to thiopental.

Anesthesia↗
PubMedDate not supplied

A comparison of desflurane and isoflurane in prolonged surgery.

STUDY OBJECTIVE: To compare desflurane with isoflurane in several anesthetic situations. DESIGN: Intubating conditions, hemodynamic response to intubation, maintenance hemodynamics, and speed of recovery from desflurane and isoflurane anesthesia were evaluated. In addition, interaction with a muscle relaxant at low and high concentrations of the anesthetics were compared. SETTING: Thomas Jefferson University Hospital. PATIENTS: Thirty-two patients who received general anesthesia for lengthy, mostly orthopedic procedures. INTERVENTIONS: Immediately after induction with thiopental sodium, desflurane or isoflurane in nitrous oxide-oxygen was administered via face mask. Anesthesia was deepened until end-tidal concentration reached 1.7 minimum alveolar concentration (MAC). The trachea was intubated without the aid of a muscle relaxant. Heart rate (HR) and blood pressure (BP) were recorded before and at 1, 2, 4, 5, and 10 minutes after intubation. Noninvasive cardiac output (CO) and systemic vascular resistance (SVR) were determined while the patient was awake, immediately before intubation, and at 5 and 10 minutes after intubation. Following intubation, the concentration of desflurane or isoflurane was lowered until the end-tidal concentration reached 0.65 MAC (low-MAC group), 1.25 MAC (high-MAC group), or 0 MAC (control group). Pancuronium bromide in 0.005 mg/kg doses was administered incrementally until T1 (first twitch of train-of-four) was depressed more than 90%. ED50 and ED95 for pancuronium with balanced anesthesia and for desflurane or isoflurane in low and high MACs, as well as speed of recovery, were determined. The time to responsiveness and awakening also was determined. MEASUREMENTS AND MAIN RESULTS: There was no significant difference between desflurane and isoflurane in intubating conditions or in BP or HR response to tracheal intubation. Both anesthetics increased HR significantly during induction. BP rose with desflurane at the preintubation point; other points showed no difference. A hyperdynamic response of increased HR and BP above 20% of baseline values was seen more frequently with desflurane (n = 7) than with isoflurane (n = 1). CO was elevated at all times after induction for low and high concentrations of both drugs, while SVR decreased over the same time with no significant difference between drugs. ED50 and ED95 for pancuronium were similar under desflurane and isoflurane at both low and high MAC, but they were significantly lower than under balanced anesthesia. Awakening times were similar for desflurane and isoflurane. CONCLUSIONS: Desflurane is similar to isoflurane in providing anesthesia for intubation and maintenance. Desflurane tends to increase HR and occasionally causes a hyperdynamic response during rapid deepening of anesthesia. It is very similar to isoflurane in its interaction with pancuronium.

Adult↗