Thomas M. Fuhrman

Patterns of prescribing and administering drugs for agitation and pain in patients in a surgical intensive care unit

ObjectivesTo describe the variety of medications prescribed along with the doses administered and routes of administration, and to delineate the clarity of orders written and the accuracy of transcription of drugs used for sedation, anxiety, pain, and neuromuscular blockade in a surgical intensive care unit (ICU). DesignA prospective, observational study of drug-related information collected from forms used by physicians and nurses. SettingThree adult surgical ICUs at an academic medical center. Patients were admitted to a surgical service and co-managed by the surgical ICU team and primary surgical service. PatientsConsecutive patients admitted to all of these units from September 1992 to January 1993. InterventionsNone. Measurements and Main ResultsInformation on prescribing and administering sedatives, analgesics, and neuromuscular blocking drugs was obtained from data collected on 221 patients. A total of 202 (91%) patients received, on average, 1.9 ± 1.4 study drugs (range 0 to 9) in a wide variety of combinations. There were 2,103 total doses administered from 448 drug orders. Ninety percent of study drug orders were written for administration on an “as-needed” basis; in 42% of these orders, the indication for use was not specified. On average, only 27% of the maximal allowable daily dose was administered; this number ranged from 15% for hydromorphone to 77% for chlordiazepoxide. Morphine sulfate, the most commonly prescribed drug, was ordered primarily for intravenous administration in 84% of patients. Morphine sulfate was prescribed using 19 different doses (written as a range of doses) and 13 different dosing intervals. Transcription discrepancies were observed in 17% of orders. In 2.7% of doses, the actual dose that was administered could not be determined. ConclusionsA wide variety of sedatives and analgesics are frequently used in surgical ICU patients. These agents are often ordered on an “as-needed” basis using a range of doses, sometimes without adequate directions about the indication for their use. Daily doses received are significantly less than their maximum allowable daily doses. Orders for these medications are sometimes transcribed and charted incorrectly. In contrast, neuromuscular blocking agents are not commonly prescribed. Future studies are needed to improve order writing of these agents, and to determine the criteria used by physicians and nurses in the selection and administration of these agents, the outcomes of therapy, and the most cost-effective regimen. (Crit Care Med 1994; 22:974–980)

Evaluation of collateral circulation of the hand.

In 1929, Edgar V. Allen described a noninvasive evaluation of the patency of the arterial supply to the hand of patients with thromboangitis obliterans (Am J Med Sci 1929;178:237). In the early 1950s, Allens test was modified (Wright I. Vascular diseases in clinical practice. Chicago: Year Book Medical Publishers, 1952) for use as a test of collateral circulation prior to arterial cannulation. This test involves the examiner occluding the patients ulnar and radial arteries while the patient makes a fist, causing the hand to blanch. The patient is then asked to extend the fingers. After the hand is open, the examiner releases the ulnar artery while continuing to maintain pressure on the radial artery. Adequate collateral circulation is felt to be indicated by return of normal color to the hand. The patient is instructed not to hyperextend the fingers when opening the hand. Hyperextension may cause a decrease in perfusion to the arch, possibly resulting in a false interpretation of the Allen test (Anesthesiology 1972;37:356). The modified Allens test can be performed quickly and easily, but it is susceptible to error. (With Allens original test, both hands were tested simultaneously. The patient clenched both fists tightly for 1 minute while the examiner compressed one artery of each hand. This method helps diagnose complete occlusion, just as Allen intended. The test was later modified, however, to evaluate the adequacy of collateral circulation. To perform the modified Allens test, the examiner compresses both arteries while the patients fists are clenched. The patient then opens the hand, and the adequacy of circulation is evaluated when the examiner releases one of the arteries.) This study was designed to combine the modified Allens test with the sensitivity of oximetry and plethysmography to provide a quantifiable and reproducible evaluation of the palmar collateral circulation with or without the subjects cooperation. Superficial palmar arches of 90 normal volunteers (aged 22–45 years) were evaluated with the modified Allens test. These results were compared with the flow patterns demonstrated by plethysmography and pulse oximetry. All of the modified Allens tests were normal, with the palmar blush occurring in an average of 2.3 seconds (range, 2–5 s). Results were recorded independently by two observers, with agreement in all cases. Four of the 90 (4.4%) palmar arches were found to have abnormal circulatory patterns. Plethysmography clearly demonstrated the dominant arterial supply to the hand and, in appropriate cases, indicated the existence of an incomplete arch. The four abnormal circulatory patterns (two incomplete palmar arches and two other aberrant arterial communications) were clearly shown by plethysmography. Pulse oximetry was found to be too sensitive. Significant changes in flow did not result in a decrease in saturation. Only the incomplete superficial palmar arches resulted in a change in saturation. The two abnormal arterial communications were not detected by pulse oximetry. Pulse oximetry also could not show dominant flow patterns. Our findings indicate that plethysmography can be used to demonstrate palmar collateral circulation, but that pulse oximetry cannot.

Comparison of the efficacy of esmolol and alfentanil to attenuate the hemodynamic responses to emergence and extubation

STUDY OBJECTIVE To define the ability of esmolol and alfentanil to control the hemodynamic changes associated with extubation and emergence. DESIGN Randomized, double-blind, placebo-controlled study. SETTING General surgery operating rooms at a university hospital. PATIENTS Forty-two ASA physical status I and II patients without history of cardiac or pulmonary disease undergoing surgery not involving the cranium or thorax. INTERVENTIONS Patients were given either a bolus dose of normal saline followed by an infusion of normal saline, a bolus dose of alfentanil 5 micrograms/kg followed by an infusion of normal saline, or a bolus dose of esmolol 500 micrograms/kg followed by an infusion of esmolol 300 micrograms/kg/min. MEASUREMENTS AND MAIN RESULTS Emergency and extubation resulted in significant increases in heart rate (HR) and blood pressure (BP) in the placebo group. Alfentanil controlled the responses to emergence but prolonged the time to extubation (p < 0.05). Esmolol significantly controlled the responses to emergence and extubation (p < 0.05). CONCLUSIONS Emergence and extubation after inhalation general anesthesia result in significant increases in BP and HR in healthy patients. An esmolol bolus dose and subsequent infusion significantly attenuated these responses. A small bolus dose of alfentanil minimized the responses to emergence but prolonged the time to extubation and was no longer protective at that point.

Comparison of digital blood pressure, plethysmography, and the modified Allen's test as means of evaluating the collateral circulation to the hand

The collateral circulation to the hand was evaluated on 70 hands of healthy volunteers. Comparisons were made between the results of the modified Allens test alone and the Allens test combined with either plethysmography or digital blood pressure. The modified Allens test requires patient cooperation and the results can be subjective. Plethysmography does not require patient cooperation and produces a signal that varies directly with flow; however, this is not a quantifiable signal. Digital blood pressure (measured by the 2300 Finapres noninvasive blood pressure monitor, Ohmeda, Englewood, CO, USA) also requires no patient cooperation. The values produced are of clinical value and reproducible. Both the plethysmograph and digital blood pressure monitors were able to demonstrate the dominant arterial vessel of the hand. The digital blood pressure monitor produces an objective recordable numerical value, an accepted clinical parameter, and it does not require patient cooperation. The use of a digital blood pressure monitor may prove to be an acceptable alternative to the traditional Allens test.

Technology evaluation report: Obtaining pulse oximeter signals when the usual probe cannot be used

We studied the function of four different monitoring probes used with the Satlite™ pulse oximeter (Datex, Helsinki). The aim was to evaluate ease of use and compare the function of the probes and their attachment methods in different locations (finger, toe, ear, thumb web, instep, wrist, and ankle).Two similar pulse wave oximeters were used in the study. To select the best signal we determined the absolute height of the Plethysmographic waveform for each probe. Probes were compared on awake normal adult volunteers (N=13), in anesthetized adult patients (N=12), and in neonates weighting 500–1000 g (N=8). In all the adult trials, the clip-on finger probe was used as a reference, and probes taped or clipped onto the finger provided adequate signals in comparison. Taped-on probes gave also satisfactory results on the toe. It was difficult to get a quality signal from the ear or from the thumb web, however. In the neonates, taped-on probes were most satisfactory.

Elective tracheostomy for a patient with a history of difficult intubation

The anesthetic challenge of managing a difficult airway is demanding under the best of conditions. An emergency operation compounds the difficulty. Seldom do we have the opportunity to truly plan for a possible emergency. This report presents a solution to the problem of knowing of a difficult airway but having no control over the timing or possible emergent state of the operation.