The Science Journal of the American Association for Respiratory Care

2001 OPEN FORUM Abstracts


Kenneth Miller,RRT,MEd;Dr. Jay Kaufman; Dr. Keith Kreitz; Paul Miller, RRT; Chris Moore, Rpharm.Lehigh Valley Hospital. Allentown, PA 18105

Introduction:The utilization of paralytic drugs has become an essential pharmacological interventionduring inverse ratio pressure control ventilation1. The setting ofa long inspiratory time to elevate the mean airway pressure is often met withdeterioration in clinical parameters in the responsive ventilated patient. Historically,ventilators have locked out the patient from breathing spontaneously duringthe fixed mandatory inspiratory phase which leads to poor patient-ventilatorinterfacing, reduction in delivered tidal volume, reduced ventilation and oxygendesaturation2. The administration of pharmacological paralysis isusually necessary to re-establish patient-ventilator synchrony. The Drager Evitaventilator with Autoflow allows the patient to access flow and interact withthe ventilator throughout the inspiratory phase of mandatory ventilation, eliminatingthe need to administer paralytics. We present a case study that demonstratesthis view.

Case Summary:A fifty-three year old male was admitted with acute pancreatitis. After surgicalintervention he was successfully placed on conventional volume ventilation.Later, in the clinical course, he developed sepsis induced ARDS. P/F ratio droppedbelow 100 and chest x-ray demonstrated bilateral pulmonary infiltrates. Pressurecontrol ventilation was instituted with an inspiratory time of two seconds.Pharmacological paralysis was initiated to maintain patient ventilator synchronyand adequate levels of gas exchange.Cisatracurium was administered for a totalof eighteen consecutive days prior to initiation of ventilatory support withthe Evita. During the clinical course, the dosage needed to be increased ona daily basis to maintain the desired clinical endpoints. On the eighteenthday the patient required a rate of 13mcg/kg/minute or 2500mg of paralytic perday to achieve and maintain the desired clinical endpoints. During clinicalstabilization several attempts were made to remove Cisatracurium to assess neuromuscularfunction and patient responsiveness. Each attempt failed secondary to patient-ventilatordysynchrony associated with tachypnea, tachycardia, and oxygen desaturation.After the third failed challenge, the patient was placed on the Evita ventilatorin the PCV+ mode with the identical ventilatory parameters. Improved ventilator-patientinterfacing allowed discontinuation of the paralytic drug. Throughout the remainingclinical course of mandatory ventilation no re-administration of a paralyticwas necessary despite increasing the inspiratory time. Spontaneous interactionswere noted during the inspiratory phase of ventilation with no reduction inthe mean airway pressure. Weaning of the patient is currently progressing viapressure support.

Conclusion: Patientswith respiratory failure requiring inverse ratio pressure control ventilationneed drug free periods during the infusion of paralytic medications to evaluatethe neurological status and to reduce the risk of prolonged paralysis when theparalytic is discontinued. Clinical assessment during paralytic administrationis critical in evaluating patient responsiveness and neuromuscular function.A long inspiratory time is necessary to maintain an adequate mean airway pressureto insure adequate oxygenation in these patients. Conventional ventilators requirepatient-ventilator synchrony to maintain adequate mean airway pressure; makingthe discontinuation of paralytics problematic. Our case demonstrates that useof Autoflow in the PCV+ mode allows patient-ventilator while maintaining meanairway pressure without the utilization of pharmacological paralysis.

1. Luce J. AcuteLung Injury and the Acute Respiratory Distress Syndrome. Critical Care Med.1998;26:369-375.

2. Lachman B. OpenUp the Lung and Keep the Lung Open. Intensive Care Med. 1992; 18:319-322.