An open cremaster muscle preparation for the study of blood vessels by in vivo microscopy.

Background — Postoperative atrial fibrillation (AF) is a common complication of cardiac surgery and has been associated with increased incidence of other complications and increased hospital length of stay (LOS). Prevention of AF is a reasonable clinical goal, and, consequently, many randomized trials have evaluated the effectiveness of pharmacological and nonpharmacological interventions for prevention of AF. To better understand the role of various prophylactic therapies against postoperative AF, a systematic review of evidence from randomized trials was performed. Methods and Results — Fifty-two randomized trials (controlled by placebo or routine treatment) of β-blockers, sotalol, amiodarone, or pacing were identified by systematic literature search. The 3 drug treatments each prevented AF with the following odds ratios (ORs): β-blockers, 0.39 (95% CI, 0.28 to 0.52); sotalol, 0.35 (95% CI, 0.26 to 0.49); and amiodarone, 0.48 (95% CI, 0.37 to 0.61). Pacing was also effective; for biatrial pacing, the OR was 0.46 (95% CI, 0.30 to 0.71). The influence of pharmacological interventions on LOS was as follows: −0.66 day (95% CI, 2.04 to 0.72) for β-blockers; −0.40 day (95% CI, 0.87 to 0.08) for sotalol; and −0.91 day (95% CI, 1.59 to −0.23) for amiodarone. The influence for biatrial pacing was −1.54 day (95% CI, −2.85 to −0.24). The incidence of stroke was 1.2% in all the treatment groups combined and 1.4% in controls (OR, 0.90; 95% CI, 0.46 to 1.74). Conclusions — β-Blockers, sotalol, and amiodarone all reduce risk of postoperative AF with no marked difference between them. There is evidence that use of these drugs will reduce LOS. Biatrial pacing is a promising new treatment opportunity. There was no evidence that reducing postoperative AF reduces stroke; however, data on stroke are incomplete.

Interventions on Prevention of Postoperative Atrial Fibrillation in Patients Undergoing Heart Surgery A Meta-Analysis

Uptake of local anesthetics injected into the subarachnoid space determines which neuronal functions are affected during spinal anesthesia. Elimination of local anesthetics from the subarachnoid space determines the duration of these effects. Distribution of local anesthetics within cerebrospinal fluid (CSF) determines the extent of altered neuronal function. Uptake and elimination have been reviewed previously (1). The present review deals with distribution, the determinant of the level of spinal anesthesia. Studies of drug distribution usually rest upon measurements of concentrations of the drug as a function of time after administration. Technical and ethical considerations make it impossible to take multiple samples of CSF at different levels of the subarachnoid space in patients. Reliance must, therefore, be placed upon estimates of distribution of local anesthetics in CSF not by measuring drug concentrations in CSF but, instead, by measuring the extent of neurologic responses to local anesthetics in CSF. The neurologic response that will be relied upon in this review, for estimation of local anesthetic distribution in CSF, is the spinal segmental level of anesthesia. Anesthesia is defined (for the present purposes only) as loss of pinprick sensation. This definition of anesthesia is employed because it is the definition most widely used by clinicians in determining the level to which local anesthetic solutions have spread. Differences between the levels of anesthesia as thus defined and levels of analgesia, somatic motor paralysis, sympathetic denervation, and other forms of neuronal impairment are not dwelt upon. These other forms of

Distribution of local anesthetic solutions within the subarachnoid space.

Background— Postoperative atrial fibrillation (AF) is a common complication of cardiac surgery and has been associated with increased incidence of other complications and increased hospital length of stay (LOS). Prevention of AF is a reasonable clinical goal, and, consequently, many randomized trials have evaluated the effectiveness of pharmacological and nonpharmacological interventions for prevention of AF. To better understand the role of various prophylactic therapies against postoperative AF, a systematic review of evidence from randomized trials was performed. Methods and Results— Fifty-two randomized trials (controlled by placebo or routine treatment) of β-blockers, sotalol, amiodarone, or pacing were identified by systematic literature search. The 3 drug treatments each prevented AF with the following odds ratios (ORs): β-blockers, 0.39 (95% CI, 0.28 to 0.52); sotalol, 0.35 (95% CI, 0.26 to 0.49); and amiodarone, 0.48 (95% CI, 0.37 to 0.61). Pacing was also effective; for biatrial pacing, the OR w...

Interventions for preventing post‐operative atrial fibrillation in patients undergoing heart surgery

Atrial fibrillation after coronary artery bypass grafting. Is it a disorder of the elderly

Clinical pharmacology of the new beta-adrenergic blocking drugs. Part 10. Beta-adrenoceptor blockade and coronary artery surgery

SUMMARY Static total and lung compliance measurements were made in five healthy term-pregnant women immediately before and after vaginal delivery using a super-syringe and oesophageal balloon. Chest wall compliance was calculated from the formula of Comroe and associates (1962). The influence of supine recumbent v. lithotomy position was also evaluated and compared to five non-pregnant women. Following parturition, total and chest wall compliances increased significantly while lung compliance changes were variable and of smaller magnitude. In most patients, recumbent total and chest wall compliances were higher than lithotomy position values. The difference was greatest in the antepartum group and smallest in the control group. The mass factor of the enlarged uterus elevating the diaphragm appears to be the main cause for the antepartum decreases in total and chest wall compliance.

Static compliance before and after vaginal delivery

Cerebrospinal fluid pressures during labor.

Changes in cerebrospinal fluid pressure, venous pressure, and arterial pressure induced by different concentrations of halothane were measured in ten elderly patients prior to the beginning of surgery. Cerebrospinal fluid and venous pressures were recorded by a water manometer and arterial pressure with a sphygmomanometer. Tidal volume, pH, and pCO2 were determined intermittently in order to prevent changes in respiratory physiology. The patients were intubated with a cuffed endotracheal tube and given 1/2 to 2 vol. per cent halothane, for periods of 15 minutes or longer, using a non-rebreathing system and a Fluotec vaporizer.

/pdf/cerebrospinal-fluid-pressures-during-halothane-anaesthesia-168kftj7rc.pdf

Cerebrospinal fluid pressures during halothane anaesthesia.

The hormonal responses to anaesthesia and cardiac surgery were studied in patients undergoing valve or coronary bypass surgery. Marked increases in antidiuretic hormone levels as a result of surgical stress were seen, and were of approximately equal magnitude in both groups. Although both groups also showed marked increases in plasma cortisol levels in response to operations, this response appeared to be relatively blunted in valve surgery patients, especially at the end of operation and in the intensive care unit. This blunted cortisol response may be a manifestation of exhaustion of adrenocortical reserves in valvular surgical patients whose sympathoadrenal system has already been chronically stimulated by a low output state. The important role of the neuroendocrine system in maintaining homeostasis postoperatively has long been recognized; this relative cortisol deficiency may be aetiologically related to poor postoperative recovery in critically ill valvular surgery patients.

https://link.springer.com/content/pdf/10.1007%2FBF03007799.pdf

Louis R. Orkin

Papers

Clinical pharmacology of the new beta-adrenergic blocking drugs. Part 10. Beta-adrenoceptor blockade and coronary artery surgery

Static compliance before and after vaginal delivery

Cerebrospinal fluid pressures during labor.

Cerebrospinal fluid pressures during halothane anaesthesia.

Cortisol and antidiuretic hormone responses to stress in cardiac surgical patients