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Biomedical subjects

J H Waters

Publications and source records attributed to J H Waters.

14 recordsLinked to original sources
PubMed1998

Considerations in placement of right internal jugular cannulas.

This case report describes a patient who had paroxysmal ventricular bigeminy of an unrecognized etiology. After 24 hours of observation, it was noted that the patient's head position correlated with the bigeminy. A single-lumen infusion catheter, which had been placed through an internal jugular cannula, was transduced and demonstrated a ventricular pressure waveform. This catheter was removed and the ectopy resolved. The factors associated with this arrhythmia are discussed.

Aged↗
PubMed1997

Patient and surgeon satisfaction with extremity blockade for surgery in remote locations.

In a practice that may be unique to military health care, extremity nerve blocks are established by anesthesiologists before transporting the patient to a remote clinic for surgery without further monitoring by anesthesia personnel. The safety and acceptance of this practice was assessed through a prospective survey of the surgeons and their patients. Six hundred seventy-seven blocks were performed in a 1-yr period with no adverse events related to this practice. Completed surveys were received from 406 (60%) of the surgeons and 232 (34%) of the patients. Of the blocks performed, 638 (94%) were brachial plexus blocks, with axillary blocks accounting for 87% of the brachial plexus blocks. Of the responding patients, 78% stated that they would be willing to undergo a repeat block. The surgeons were satisfied with the operating conditions in 96% of the cases. This study supports the safety and efficacy of this practice.

Adolescent↗
PubMed1996

Preoperative glycopyrrolate: oral, intramuscular, or intravenous administration.

STUDY OBJECTIVE: To evaluate the effects of oral, intramuscular (i.m.) and intravenous (i.v. glycopyrrolate on oral and gastric secretions, and to assess how these routes of administration change intubating conditions. DESIGN: Randomized, double-blinded study. SETTING: University hospital operating room. PATIENTS: 37 ASA status I and II general anesthesia patients. INTERVENTIONS: Patients were randomized to receive glycopyrrolate or placebo just before surgery by three routes: oral, i.m., and i.v.. Glycopyrrolate was received once by one route and placebo by the other two routes. A placebo group received three placebos and no glycopyrrolate. MEASUREMENTS AND MAIN RESULTS: Mouth conditions and intubating conditions were qualitatively assessed by the patient and the intubating anesthesiologist. No difference between groups was noted. Oral and gastric volumes were measured and showed significantly less gastric volume for the i.v. group as compared with the other groups. Oral secretions were reduced in both the i.v. and i.m. groups when compared with placebo or glycopyrrolate administered orally. CONCLUSIONS: Preoperative glycopyrrolate is significantly more effective at reducing oral and gastric secretions if administered intravenously immediately before induction.

Adjuvants, Anesthesia↗
PubMed1996

Conus medullaris injury following both tetracaine and lidocaine spinal anesthesia.

Multiple reports of cauda equina syndrome and transient radicular nerve root irritation have suggested that lidocaine spinal anesthesia may be responsible. In this case report, a patient with a preexisting diabetic neuropathy received a partial block following a tetracaine spinal, which was followed by a lidocaine spinal. Following block resolution, a new conus medullaris syndrome was diagnosed. Because of the close proximity of the cauda equina and the conus medullaris, differentiation between these syndromes can be difficult. The preexisting diabetic neuropathy may have predisposed this patient to neurologic injury. The choice of a different local anesthetic drug with less neurotoxic potential such as bupivacaine may have prevented this injury.

Anesthesia, Spinal↗
PubMed1996

Plasma potassium response after tromethamine (THAM) or sodium bicarbonate in the acidotic rabbit.

The purpose of this study was to evaluate the plasma potassium (K+) response after administration of tromethamine (THAM) or sodium bicarbonate (NaHCO3) in an acidotic rabbit model. Eighteen healthy, adult female New Zealand White rabbits were subjected to severe hypoxia until a base deficit of -10 mEq/L resulted. Rabbits were then randomized to receive THAM solution, NaHCO3, or no drug (control). The drug was administered over 2 min in quantities calculated to correct a base deficit of 10 or greater. Plasma K+ and sodium (Na+) were measured for 45 min after drug administration. No difference in K+ response was noted after THAM, NaHCO3, or no drug. In contrast, THAM resulted in significantly lower Na+ concentrations when compared to the NaHCO3 or the control group (P < 0.05). In this rabbit model, alkalinization after THAM administration results in K+ changes similar to those after NaHCO3. THAM should be considered when treating acidosis in patients where hypernatremia is a concern.

Acidosis↗
PubMed1995

A re-evaluation of the ability of thiopental to identify cerebrospinal fluid in epidural catheter aspirate.

STUDY OBJECTIVE: Sodium thiopental has been used to determine whether fluid aspirated from an epidural catheter is previously injected local anesthetic or cerebrospinal fluid (CSF). The purpose of this study was to test the efficacy of this test in distinguishing opioids from CSF. DESIGN: in vitro study. SETTING: Laboratory of a university hospital. MEASUREMENTS AND MAIN RESULTS: Three in vitro studies were performed. The first study tested for precipitation when thiopental was mixed with several commonly used epidural medications. Then, thiopental was mixed in combinations of opioids with local anesthetics to see if the opioid might prevent the precipitation of the local anesthetics. Finally, lidocaine was serially diluted and precipitation with thiopental was assessed. It was found that certain concentrations of opioids as well as normal saline do not precipitate with thiopental. In addition, the ratio of opioids to local anesthetic of 10:1 prevented precipitation when thiopental was added. Local anesthetics combined with cerebrospinal fluid in a 1:10 ratio produced a precipitate on mixing with thiopental. CONCLUSIONS: Use of thiopental to differentiate opioids from cerebrospinal fluid is unreliable. In addition, in some simulated situations, opioids may mask the presence of local anesthetic.

Anesthesia, Epidural↗
PubMed1995

Role of minor electrolytes when applied to Stewart's acid-base approach in an acidotic rabbit model.

Current clinical practice regarding acid-base balance is derived from the traditional Henderson-Hasselbalch equation. An alternate theory, developed by Stewart, relates hydrogen ion concentration ([H+]) changes to three independent variables: the strong ion difference, weak acids, and PCO2. The insight into acid-base balance gained by this approach has potentially important clinical applications. To test the theory in vivo, electrolyte and blood gas values were measured in rabbits subjected to a period of hypoxia sufficient to produce a severe metabolic acidosis, followed by a period of reoxygenation. These variables were used to calculate [H+] by Stewart's original formula, which was then compared to the measured value. A high correlation was found between measured and calculated values for a pH range of 7.3-7.6; however, progressive deterioration in correlation was observed outside this range. Perhaps the presence of an unidentified anion, thought to be phosphate, causes a breakdown in the accuracy of Stewart's formula at pH extremes. The addition of phosphate values to the calculation, along with calcium and magnesium, restored the agreement throughout the physiologic range. To make the formula clinically applicable, modification to incorporate phosphate levels is required to achieve the necessary accuracy in biologic solutions at more acidemic pH ranges.

Acidosis↗
PubMed1993

Glucose in epidural catheter aspirate.

Frequently fluid may be aspirated from epidural catheters during epidural anesthesia/analgesia. This fluid may be either cerebrospinal fluid or local anesthetic. Several methods for differentiation of the two fluids have been recommended. In this study, the reliability of the "glucose test" was analyzed. Epidural catheters were inserted into 43 healthy, nondiabetic parturients and then gently aspirated. Aspirate was tested for glucose using glucose oxidase paper. Positive aspirates were assessed for the presence of prealbumin, which is a protein marker for cerebrospinal fluid. Of the patients undergoing cesarean section, 17 of 27 patients yielded a glucose-positive aspirate, and of the patients undergoing labor analgesia, 6 of 16 patients were found to be positive for glucose. None of these patients developed total spinal anesthesia or postdural puncture headache. Visually, none of the aspirates were significantly blood-tinged, blood being a possible source of glucose. When the glucose-positive aspirates were subjected to immunoelectrophoresis, 6 of 7 aspirates revealed a prealbumin band. In conclusion, the glucose test for cerebrospinal fluid may be misleading. The source of this glucose may be normal cerebrospinal fluid drainage into the epidural space.

Analgesia, Epidural↗
PubMed1987

Anaesthesia for combined heart and lung transplantation.

In December 1983, Harefield Hospital started a programme for combined heart and lung transplantation. Fifty-two transplants have been successfully performed, with 36 survivors (April 1986). Patient selection and anaesthetic management of both donor and recipient are discussed. Two case histories are presented which illustrate the principles of anaesthetic management and postoperative care.

Adolescent↗