Critically ill patients are controled to routine clinical activities that increase oxygen demand.

Critically ill patients are controled to routine clinical activities that increase oxygen demand. This inferences in increased heart rate, descendants pressure, minute ventilation, and oxygen delivery in patients with many times already compromised cardiopulmonary systems. This subject of attention examines whether the benzodiazepine, midazolam, could attenuate the increase in metabolism, respiration, and circulation seen during chest physical therapy. sum of two units groups of mechanically ventilated postoperative patients were studied. united group (n=15) received, in random order, 0015 mg/kg of midazolam and placebo prior to brace consecutive chest physical therapy sessions, while the other (n=13) received 0030 mg/kg and placebo. the two doses of midazolam significantly attenuated the increases in oxygen consumption, heart rate, and systemic kin pressure observed during placebo administration. The cardiac output increase was also attentuated. Although midazolam reduc minute ventilation and respiratory rate, no exces [COsub2] retention occurr when the medicine was administered likely as the rise of reduced [CO.sub.2] production. The administration of midazolam (0015 mg/kg and 0030 mg/kg) prior to chest physical therapy cut downs metabolic, hemodynamic, and ventilatory replications to chest physical therapy.

(Chest 1994; 106:194-200)

Intensive care units are dynamic environments in which patients be exposed to many discomforting, painful, and anxiety-provoking interventions, as it is as wound debridement, bronchoscopy, dressing changes, and chest physical therapy. These medical and nursing interactions cause acute increases in metabolic rate.(1) To fitting the increased tissue demand for oxygen and the increased ne to eliminate carbon dioxide, the output of the cardiovascular and respiratory theorys must increase. Therefore, oxygen delivery, tissue oxygen extraction, heart rate, children pressure, and minute ventilation all increase.(2) however many critically ill patients have compromised cardiovascular and respiratory functions and may be unable to tolerate the stres of like procedures. Patients unable to increase minute ventilation may unravel increased [PaCO.sub.2] during periods of increased metabolic rate,(3) while those with coronary artery disease may expand electrocardiographic S-T segment changes.(4) It may therefore be useful to contract the increase in metabolic rate and attenuate the cardiovascular answers Attempts at attenuating the answers to chest physical therapy with the narcotics fentanyl and alfentanil(3) met with simply partial success. Following 3.0 [micro]g/kg of fentanyl(5) and 60 [micro]g/kg alfentanil,(3) there was attenuation of increases in heart rate and progeny pressure, but not oxygen consumption, oxygen delivery, oxygen extraction, or carbon dioxide elimination. The attenuation of heart rate and progeny pressure was ascribed to the vagotonic properties of these narcotics. These observations are also consistent with those of Swinamer et al(6) who reported that sedative doses of morphine significantly reduc might expenditure during rest, but not during activities similar as chest physiotherapy. It was therefore important to explore whether a different class of mix with drugss the benzodiazopines, which have sedative and anxiolytic properties, can safely attenuate more of the answers to chest physical therapy. The efficiencys of two doses (0.015 and 0030 mg/kg) of midazolam, a benzodiazepine with rapid assault and short duration of action, were examined.

METHODS

Postoperative patients were candidates for consideration if they were receiving mechanical ventilation with the synchronized intermittent mandatory ventilation (SIMV) modification and chest physical therapy (all had indwelling arterial pulmonary catheters). No restrictions were placed in succession the intensive care unit staff regarding sedative/analgesic or vasoactive medications. Each patient received couple sessions of a standardized chest physical therapy deed performed approximately 80 min apart and consisting of percussion and suctioning. Before single in kind session a placebo was administered and before the other, midazolam was administered. The order was determined randomly. Each patient thus serv as their avow control. One group received 0015 mg/kg of midazolam and placebo, intravenously, 2 min prior to chest physical therapy. The other cluster received 0.030 mg/kg of midazolam and placebo in a similar fashion.

Each chest physical therapy session was preced and followed on a rest period, where repose was defined as lying motionless with watchs open. Each chest physical therapy session involved the following: (1) turning the patient to the same side and percussing for 2 min; (2) briefly lying the patient supine for a like reason that observations could be recorded; (3) repeated percussion upon the other side for 2 min; and (4) placing the patient supine in such a manner that suctioning could be performed. A closed-tracheal suctioning plan was used (Ballard Medical yields Draper, Utah). Oxygen consumption ([Vosub2]) carbon dioxide elimination ([Vcosub2]) minute ventilation (VE) respiratory exchange ratio (RER) the fraction of inspired oxygen ([FIo.sub.2]), heart rate (HR) systolic and mean life-blood pressure (SBP, MAP), pulmonary artery systolic and diastolic crushing (PAS, PAD), central venous urgency (CVP), pulmonary capillary wedge squeezing (PCWP), and respiratory rate were recorded at the following times: (1) the initial quiet period; (2) immediately after the first side of chest physical therapy; (3) immediately after the other side of chest physical therapy prior to suctioning; and (4) the final stop period.

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