Transesophageal color flow Doppler imaging for aortic insufficiency in patients having cardiac operations.

Transesophageal color flow Doppler findings were studied in 30 patients with aortic insufficiency who had cardiac operations. Measurements were expressed as ratios of corresponding left ventricular outflow tract dimensions. Regurgitant jet proximal width ratio was significantly related to jet area ratio (r = 0.92) and correlated poorly with the degree of jet penetration into the left ventricular cavity (r = 0.32). The vectors of the regurgitant jets were variable. Nine patients had undergone aortography. Regurgitant jet proximal width and area ratios were significantly related to angiographic grade (r = 0.88 and 0.87, respectively) in these patients. We concluded that the esophagus offers a satisfactory transducer orientation for color flow Doppler assessment of aortic insufficiency.

Effect of nerve block on response of forearm blood flow to local temperature.

To determine the role of neurotransmitter in the response of forearm blood flow (ABF) to local (forearm) skin temperature (Tsk) we measured ABF of six subjects at Tsk from 25 to 40 degrees C before (control) and after brachial plexus block (BPB). Control experiments were conducted in an ambient temperature of 27-29 degrees C, adjusted to minimize the subject's overall thermal sensation. Tsk was regulated by blowing a controlled-temperature airstream through a plastic bag enclosing the arm. We first lowered Tsk to 25 degrees C and after 20 min began to measure ABF with Whitney strain gauges. We then raised Tsk by 2.5 degrees C steps to 40 degrees C and measured ABF every 30 s for at least 10 min at each level of Tsk. Mean ABF rose from 1.1 ml X 100 ml-1 X min-1 at Tsk of 25 degrees C to 2.1 ml X 100 ml-1 X min-1 at 32.5 degrees C to 13.7 ml X 100 ml-1 X min-1 at 40 degrees C in control experiments and from 2.8 to 4.4 to 14.8 ml X 100 ml-1 X min-1 after BPB. The effect of Tsk on ABF was highly significant (P less than 0.0001) but the effect of BPB was not (P approximately equal to 0.2). At thermoneutrality, the effect of Tsk on ABF is largely independent of neural activity, since this effect is unaffected by nerve block.

Measurement of central somatosensory conduction time in patients undergoing cardiopulmonary bypass: an index of neurologic function.

It is feasible to monitor somatosensory evoked potentials and central somatosensory conduction times during open heart surgery and cardiopulmonary bypass with moderate or profound hypothermia. Central conduction times are reproducible, have acceptably low interpatient and intrapatient variability, and are not significantly affected by fentanyl-induced anesthesia. There is a predictable logarithmic relationship between central conduction times and temperature with the central conduction time increasing by 6.6 percent for a 1 degree C decrease in temperature. These data indicate that somatosensory conduction times may be a useful index of central nervous system integrity during open heart surgery that utilizes cardiopulmonary bypass and hypothermia.

RN to BS in nursing: historical review leads to articulation agreement.

Historically, registered nurses who have graduated from associate degree or diploma programs and who wish to obtain a baccalaureate degree in nursing have been required to pass challenge examinations to obtain credit for their previous nursing knowledge. A review of this university's policy regarding challenge examinations convinced faculty to establish a transition course and to actively pursue articulation agreements with local community colleges. Through these agreements, RN students would be granted 29 credits and bypass the junior year. This article is written to encourage others to review their policies to facilitate educational mobility for the RN/BS student.

A comparison between the effects of fentanyl, droperidol with fentanyl, and halothane anaesthesia on intra-ocular pressure in adults.

The effects of fentanyl 3.0 micrograms/kg (group 1), droperidol 0.1 mg/kg with fentanyl 3.0 micrograms/kg (group 2), and halothane 0.5% inspired concentration (group 3) on intra-ocular pressure were compared. In each group, a decrease in intra-ocular pressure was produced which was significantly lower than resting values (p greater than 0.01) and was independent of changes in arterial blood pressure. The recovery time in group 1 patients was significantly less than that of patients in group 3.

Central and spinal somatosensory conduction times during hypothermic cardiopulmonary bypass and some observations on the effects of fentanyl and isoflurane anesthesia.

Somatosensory evoked potentials (SEPs) following median nerve stimulation were recorded over Erb's point (N10), neck (N13) and scalp (N20) of 17 neurologically normal patients during hypothermic cardiopulmonary bypass. Anesthesia was induced with fentanyl and 100% oxygen, and supplemented with isoflurane as necessary. All 3 SEPs were recorded at esophageal temperatures (Te) of down to 19.5 degrees C. The central conduction time (CCT, defined as N20-N13 interpeak interval) increased exponentially with decreasing temperature (CCTTe = 1.066(37)-Te X CCT37; r = -0.96). The spinal conduction time (SCT, defined as N13-N10 interpeak interval) also increased exponentially but less steeply than the CCT (SCTTe = 1.047(37)-Te X SCT37; r = -0.89), and the N10 peak latency increased exponentially and least steeply (N10Te = 1.033(37)-Te. N10(37); r = -0.87). Anesthetic doses of fentanyl (75 micrograms/kg) did not affect the SEPs. Isoflurane (inspired concentration, 0.25-2.0%) produced dose-dependent increases in CCT of up to 13% and decreased N20 amplitude. All patients had normal CTs after rewarming and none suffered postoperative neurological deficits. Differences in slopes of the latency-temperature functions indicate that cooling produces more conduction slowing in central than in peripheral segments of the pathway and can be accounted for by estimates of the effects of cooling on synaptic delay and axonal conduction between wrist and cortex. The consistency of SEPs between patients both during stable hypothermia and when temperature was changing suggests their potential as a sensitive monitor of cerebral status during hypothermic cardiopulmonary bypass.

Anaesthetic implications for transthoracic endoscopic sympathectomy.

Transthoracic endoscopic sympathectomy is now considered the treatment of choice for patients with upper limb hyperhidrosis requiring sympathetic ablation. This procedure requires the use of an endobronchial double lumen tube and subsequent one-lung anaesthesia, a technique that is associated with a number of potential problems. Full patient monitoring is thus required and includes pulse, ECG, non-invasive blood pressure measurement, pulse oximetry, end-tidal carbon dioxide concentration and peak inspiratory airway pressure. We reviewed our anaesthetic technique and peri-operative complications in 26 patients, to assess patient safety. In our study hypoxaemia occurred commonly but was transient in all bar one case where re-expansion of the lung was required. Hypotension occurred at two stages of the procedure, but active intervention was not required, and two patients required underwater drainage of the pleural cavity for treatment of pneumothorax. With skilled anaesthetic personnel and adequate monitoring this procedure may be carried out safely.

Control of perioperative hypertension during coronary artery surgery. A randomised double-blind study comparing isosorbide dinitrate and nitroglycerin.

A reduction in the causes of myocardial ischaemia remains of prime importance during coronary artery surgery. Hypertension with the ensuing increase in myocardial oxygen demand is a major factor in the aetiology of perioperative myocardial ischaemia. Nitroglycerin (NTG) has long been used beneficially to reduce myocardial oxygen demand by its effects on the systemic and peripheral vascular resistances. An alternative nitrate, isosorbide dinitrate (ISDN) is now available as an intravenous preparation, and may offer technical advantages, both due to its stability in solution and also its longer in vivo half-life. We designed and carried out a multi-centre study to compare and evaluate the efficacy of ISDN and NTG in the management of perioperative hypertension in 85 patients undergoing elective coronary artery surgery. A total of 288 events in which the systolic blood pressure (SBP) exceeded a predetermined trigger value were observed. ISDN was successful in treating hypertension in 63% of the events, whereas NTG had an 83% success. The SBP was significantly lowered after treatment with either ISDN, 155 mmHg to 138 mmHg, or NTG, 160 mmHg to 130 mmHg. The mean successful dose rate for ISDN was 6.5 micrograms kg-1 min-1, whereas for NTG this was 3.8 micrograms kg-1 min-1. In the ISDN group less events took place possibly due to the longer duration of this drug. In many previous studies NTG has been found to be effective in controlling hypertension; ISDN offers and alternative approach in reducing hypertension.

Onset of altered interventricular septal motion during cardiac surgery. Assessment by continuous intraoperative transesophageal echocardiography.

Abnormal motion of the interventricular septum is frequently observed after uncomplicated cardiac surgery. We sought to elucidate the mechanism underlying this phenomenon by using continuous echocardiographic imaging of the heart from a constant transesophageal location in 21 patients undergoing their first cardiac operation. Quantitative global and regional functional analyses were performed in each patient at baseline (stage 1), after median sternotomy (stage 2), after sternal retraction (stage 3), after pericardiotomy (stage 4), after completion of cardiopulmonary bypass (stage 5), and after chest closure (stage 6). During the first four surgical stages, mean left ventricular fractional shortening varied little among regions with a fixed reference system (maximum range, 31.6-39.2%; p = NS) but changed dramatically after the discontinuation of cardiopulmonary bypass (stage 5). The apparent medial hypokinesis that was observed (4.9 +/- 4.7% [SD]) was accompanied by lateral hyperkinesis (65.2 +/- 4.1%, p less than 0.0001). These regional differences were completely eliminated with a floating reference system (33.6 +/- 2.7% for medial, and 34.8 +/- 1.7% for lateral; p = NS), suggesting cardiac translation. Quantitative curvature analysis supported this conclusion, with preservation of baseline regional curvature seen throughout the procedure. The mean length of individual translational vectors (reflecting systolic movement of the endocardial centroid) remained minimal (less than or equal to 1.0 mm) through stage 4 but increased more than fourfold at stage 5, continuing in a medial direction after chest closure (5.2 +/- 3.0 mm and 271 +/- 6 degrees from anterior). Thus, abnormal postoperative septal motion is not caused by removal of restraining forces of the pericardium or anterior mediastinum but rather appears to be directly related to events occurring during cardiopulmonary bypass.

Autologous predonation, haemodilution and intraoperative blood salvage in elective abdominal aortic aneurysm repair.

The feasibility of predonated autologous blood transfusion and intraoperative blood salvage in elective abdominal aortic aneurysm repair was studied. Twenty consecutive patients were evaluated, of whom five were excluded according to protocol criteria. Patients each donated 1 unit blood 14 and 7 days before operation. A third unit was withdrawn in the anaesthetic room and replaced with Hartmann's solution, producing a haemodiluted state. Intraoperative losses were minimized using the Haemonetics Cell Saver III Plus autotransfusion system. Predonated blood from two patients passed its expiry date owing to repeated operation postponements, leaving 13 patients for study. The mean(s.d.) intraoperative blood loss was 700(300) ml with a mean(s.d.) intraoperative salvage of 420(300) ml. Two patients were transfused intraoperative salvage of 420(300) ml. Two patients were transfused according to clinical need. Thus nine patients safely avoided homologous transfusion. With autologous predonation, haemodilution and intraoperative blood salvage, elective aortic aneurysm repair can be performed safely with minimal need for homologous blood.