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M P Sands

Publications and source records attributed to M P Sands.

23 records · Page 2Linked to original sources
PubMedDate not supplied

The importance of appropriate concentrations of inspired carbon dioxide on induced hypothermia under halothane-ether azeotrope anesthesia.

Thirty adult mongrel dogs were divided into 3 equal groups and studied to define the optimal PCO2 level with azeotrope (halothane-diethyl ether) anesthesia under surface hypothermia (Groups I, II and III = F1CO2 0%, 5% and 10%, respectively). All animals were cooled to 18-20 degrees C and were subjected to 30 (Group I) or 60 minutes (Groups II and III) of total circulatory arrest. Group I animals had frequent arrhythmic episodes during cooling and postoperative motor disturbances occurred in 80% despite only 30 minutes of circulatory arrest. By contrast Group II animals were less arrhythmic during cooling; were easily resuscitated following 60 minutes of arrest and only 30% developed moderate reversible motor disturbances postoperatively. Hemodynamics were similar between Groups II and III during cooling but resuscitation using an F1CO2 of 10% (Group III) was extremely difficult and required massive cardiotonic support throughout rewarming. Furthermore, two dogs in Group III died within the first two postoperative days. However, none of the 8 survivors displayed neurological abnormalities. On balance, a ventilatory regimen utilizing 5% CO2 during surface-induced hypothermia under azeotrope anesthesia resulted in optimum intraoperative management and a satisfactory postoperative course and although some CNS disturbance (high-stepping gait) was noted, all animals recovered completely.

Acid-Base Equilibrium↗
PubMedDate not supplied

Prolongation of the safe interval of hypothermic circulatory arrest: 90 minutes.

Twenty-nine adult mongrel dogs were subjected to profound hypothermia and 90 minutes of total circulatory arrest. Pure surface (Group I) hypothermia and combined surface/perfusion techniques with bubble (Group II) and membrane (Group III) oxygenator systems were employed. Circulation was arrested at average esophageal temperatures of 18.4 degrees, 11.9 degrees and 8.5 degrees C in Groups I, II and III, respectively. Three animals in Group I failed to resuscitate. All survivors in the pure surface series developed postoperative gait (hypermetria) disturbances. One intraoperative death occurred in Group II and four of eight dogs arrested at esophageal temperatures above 10 degrees C but less than 15 degrees C developed motor disturbances during a three week neurologic evaluation period. Animals arrested below 10 degrees C (esophageal) did not display postoperative neurological abnormalities. Three dogs in Group III died from a hemorrhagic diathesis of uncertain etiology. None of the survivors (5) that were cooled and arrested below esophageal temperatures of 10 degrees C developed motor or sensory disturbances. We conclude that in the canine model the central nervous system can be protected for 90 minutes of total circulatory arrest at esophageal temperatures less than 10 degrees C.

Animals↗