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Biomedical subjects

H K King

Publications and source records attributed to H K King.

At least 19 recordsLinked to original sources
PubMed1999

Isobaric spinal anesthesia for paraplegic patients.

It has long been understood that patients with spinal cord injury (SCI) above T6-7 may develop autonomic hyperreflexia (AH) and pose an anesthetic challenge. To date, there is no consensus regarding anesthesia management of these patients among anesthesiologists. Many anesthetic techniques have been proposed and used with varying success, but none of them is uniformly successful. Topical anesthetics may not block the stretch receptors and AH might still be initiated. A deep anesthesia with potent volatile agents is often necessary to prevent or treat AH. Thus, the incidence of hypotension is no different than that associated with neuraxial anesthesia. Failures with potent vasodilators such as sodium nitroprusside also have been reported. Currently, the block of the afferent pathways by neuraxial anesthesia is considered to be the most effective means of preventing AH. However, because the level of neuraxial anesthesia is difficult to detect in SCI patients, excessive high level block and subsequent severe hypotension may occur. When an isobaric solution is used, due to the lack of baricity/patient position interaction, migration of the local anesthetic is usually insignificant, so the level of anesthesia is easier to control and predict. In the past fifteen years (1982-1997), we have used isobaric spinal anesthesia (ISA) in thirteen patients with SCI for various surgical procedures. Although four of these patients had previous history of AH, there was not a single incidence of AH during the perioperative period. Our favorable experiences lead us to believe that ISA is a useful anesthetic technique for SCI patients undergoing surgery.

Adult↗
PubMed1999

Spinal anesthesia for cesarean section: isobaric versus hyperbaric solution.

BACKGROUND: The present study was undertaken to compare the outcomes of hyperbaric versus isobaric spinal anesthesia in Cesarean delivery. METHODS: The anesthetic solution was administered in sitting position as this posture is commonly used in this clinical setting. Except for the baricity of the anesthetic solution, identical technique was employed for every parturient in the study. Following administration of anesthetic solution the parturient immediately resumed horizontal supine position. The solutions used were 2.0 mL of 0.5% tetracaine in 5% dextrose (hyperbaric) for Group H (n = 30) and in cerebrospinal fluid (isobaric) for Group I (n = 30). RESULTS: Both hyperbaric and isobaric tetracaine given in sitting position provided adequate analgesic levels. However, hyperbaric tetracaine solution produced a slightly higher median peak level of wilder range, and caused a higher incidence of hemodynamic changes and subjective sensation of "feeling sick" than isobaric tetracaine. Additionally, the duration of surgical anesthesia was shorter and the sacral block was longer for hyperbaric tetracaine solution than for isobaric tetracaine solution at same dose and concentration. Only one mother in Group H needed supplemental inhalation anesthesia for a subsequent hysterectomy due to uncontrollable bleeding. There were no complications, including postpuncture headache in either group. CONCLUSIONS: Our results indicated that numerous variables must be taken into consideration in predicting the outcome of a spinal anesthesia. Alternation in the technique and individual patient factor may individually or collectively produce different results.

Adolescent↗
PubMed1999

Asystole during inadvertent high spinal anesthesia in a high risk patient without morbidity.

Sudden cardiac arrest following high spinal anesthesia (SA) in young and healthy patients with poor outcome has been reported. Extreme bradycardia, hypotension and/or asystole during SA has recently received worldwide attention. We report a high risk patient who developed cardiac arrest associated with two other episodes of extreme bradycardia, hypotension and verbal unresponsiveness during SA without adverse outcome.

Adult↗
PubMed1997

A new device: Tube Securer. An endotracheal tube holder with integrated bite-block.

Endotracheal intubation is the most commonly employed technique in airway management. Having an endotracheal tube (ETT) in place, however, does not guarantee a patent airway. Tube obstruction due to kinking, blood clots/secretion, dislodgment, or patient's biting can occur. These complications are life-threatening or even fatal. Employing a Guedel oral airway (OA) to act as a bite-block is a current common practice. However, with an OA in place does not necessarily prevent patient biting on the ETT. The author therefore proposed that this practice should have room for improvement and has made effort to design a new device for the purpose. The new dual function endotracheal tube holder with integrated bite-block as described can firmly secure the ETT in place and effectively prevent patient's biting on the tube. Therefore, it helps prevent the most serious complication of endotracheal intubation and subsequently improves patient safety.

Equipment Design↗
PubMed1996

Structure activity relationships of a series of buspirone analogs at alpha-1 adrenoceptors: further evidence that rat aorta alpha-1 adrenoceptors are of the alpha-1D-subtype.

The activity of a series of busprione analogs at recombinant and rat thoracic aorta alpha-1 adrenoceptors was investigated. Compound affinity for recombinant alpha-1A, alpha-1B and alpha-1D adrenoceptors from human and animal sources was determined by radioligand binding assays using membranes prepared from rat-1 fibroblasts expressing recombinant receptors with ( +/- )-[125l]iodo-4-hydroxyphenyl)-ethyl-aminomethyl-tetralone as the radioligand. Compound affinity and functional activity at rat aortic alpha-1 adrenoceptors were determined using endothelium denuded rings contracted with phenylephrine. BMY 7378 ¿8-(2-[4-(2-methoxyphenyl)-1-piperazinyl]-ehtyl)-8-azaspiro [4,5]decane-7,9-dione dihydrochloride¿ and MDL 73005EF ¿8-[2-(1,4-benzodioxan-2-ylmethylamino) ethyl]-8-azaspiro[4,5]decane-7,9-dione hydrochloride¿ were found to have significant selectivity for the alpha-1D-subtype and were high affinity antagonists of the alpha-1 adrenoceptors in the rat aorta. Leverage plot analysis of affinities of the buspirone analogs and a series of structurally diverse alpha-1 antagonists for recombinant alpha-1 adrenoceptors and rat aorta alpha-1 adrenoceptors demonstrate that the alpha-1 adrenoceptors in the rat aorta are predominantly of the alpha-1D subtype.

Animals↗
PubMed1996

Airway managements of patients with maxillofacial trauma.

Airway management in patients with maxillofacial trauma (MFT) is usually complicated. This is not only because the trauma directly involves the airway itself, but also the commonly associated injuries and conditions, such as cervical fracture and full stomach, often limit the options in management. The disruption of normal anatomy makes laryngoscopy, endotracheal intubation and even placement of a pharyngeal airway not only technically difficult, but sometimes even hazardous. Additionally, these patients are often in acute respiratory distress. They are often irritable and uncooperative due to underlying hypoxemia, alcohol or drug intoxication. Airway management of MFT victims is certainly challenging, if not difficult. As the clinical condition varies greatly, each patient represents a unique challenge and therefore, no single or uniform method can be adopted. This article will focus on the techniques and instrumentations currently applicable for handling the problems.

Airway Obstruction↗
PubMed1995

BMY 7378 is a selective antagonist of the D subtype of alpha 1-adrenoceptors.

BMY 7378 (8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-8- azaspiro[4.5]decane-7,9-dione dihydrochloride), a 5-HT1A receptor partial agonist, also binds to alpha 1-adrenoceptors. Competition assays were performed using (+/-)-beta-([125I]iodo-4-hydroxyphenyl)-ethyl-aminomethyl-tetralone ([125I]HEAT), and membranes prepared from Rat-1 fibroblasts expressing hamster alpha 1b-, bovine alpha 1c-, or rat alpha 1d-adrenoceptor, or their respective human homologues. Results indicate that BMY 7378 is selective for the alpha 1D-adrenoceptor subtype (pKi: hamster alpha 1b-adrenoceptor 6.2 +/- 0.03, human alpha 1b-adrenoceptor 7.2 +/- 0.05; bovine alpha 1c-adrenoceptor 6.1 +/- 0.02, human alpha 1c-adrenoceptor 6.6 +/- 0.20; rat alpha 1d-adrenoceptor 8.2 +/- 0.06, human alpha 1d-adrenoceptor 9.4 +/- 0.05) and has high affinity (pA2, 8.9 +/- 0.1) for rat aorta alpha 1-adrenoceptor.

Adrenergic alpha-1 Receptor Antagonists↗