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Biomedical subjects

J F Hardy

Publications and source records attributed to J F Hardy.

At least 55 records · Page 3Linked to original sources
PubMed1993

A simple classification of the risk in cardiac surgery: the first decade.

Since 1980, the operative risk in all our cardiac surgical patients has been assessed before surgery. In light of reports of changes in cardiac surgical populations, we reexamined our practice and risk classification. The purpose of this study was to compare the surgery performed, the characteristics of the patients operated upon and the hospital mortality in our institution in two epochs ten years apart. In 1989-90, the 2029 consecutive cardiac surgical patients who had the same operations as the 500 patients of a 1980 study in our institution were prospectively stratified using our risk classification based on the number of risk factors (RFs) present: normal-risk patient = no RF, increased risk = 1 RF, high risk > or = 2 RFs. These two cohorts of patients were compared. From 1980 to 1990, the proportion of high-risk patients tripled whereas the proportion of normal-risk patients diminished by one third and the proportion of increased risk remained unchanged. The incidence of the following RFs increased: poor left ventricular function, advanced age, emergency surgery, reoperation and other systemic disorders. In coronary artery surgery patients, the incidence of unstable angina/recent myocardial infarction and of obesity also increased. In noncoronary artery surgery patients, the incidence of heart failure increased while obesity remained unchanged. The difference in hospital mortality among the three risk classes was significant within both study periods. The mortality in each risk class and total mortality did not change between 1980 and 1990.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1993

Inotropic support of the heart that fails to successfully wean from cardiopulmonary bypass: the Montreal Heart Institute experience.

The selection of an appropriate therapeutic regimen, especially in patients with preexisting cardiac dysfunction prior to surgery, is a crucial element for successful separation from cardiopulmonary bypass (CPB). At the present time there are no definitive studies to determine which treatment modality, or combination of treatments, is optimal in this patient population. A brief review of the literature is presented to answer the following questions: (1) Should inotropic support be administered in anticipation of failure to wean from CPB? and (2) Which inotrope or combination of drugs is best? There is no evidence at present that the prophylactic administration of inotropes to assist separation from CPB may result in damaging effects to the myocardium in humans. Inasmuch as tachycardia is avoided and coronary perfusion pressure is maintained within the normal range, prophylactic inotropes may be of benefit to patients with preexisting myocardial dysfunction during weaning from CPB by allowing a smoother separation and a shorter time on CPB. While no specific drug has been proven superior, the use of phosphodiesterase inhibitors as part of the regimen to provide inotropic support in these patients may exert a beneficial effect on myocardial ischemia and reperfusion injury. Prophylactic support of the circulation during separation from CPB, especially with phosphodiesterase inhibitors, may be indicated in this specific patient population as part of the strategy to ensure maximal preservation of myocardial function.

Adrenergic beta-Agonists↗
PubMed1992

Successful non-surgical extraction of a knotted pulmonary artery catheter trapped in the right ventricle.

A patient is presented in whom a pulmonary artery catheter (PAC) formed a knot which was fixed in the region of the tricuspid valve chordea. The PAC was successfully and nonsurgically freed from its attachment and removed. A guide wire was introduced by the distal port of the PAC and under fluoroscopy the PAC was manipulated free and then extracted easily.

Catheterization, Swan-Ganz↗
PubMed1992

Natural and synthetic antifibrinolytics in cardiac surgery.

In an effort to reduce morbidity associated with transfusion of blood products, the use of antifibrinolytics to decrease bleeding and transfusions after cardiopulmonary bypass (CPB) is receiving widespread attention. The predominant haemostatic defect induced by CPB and, therefore, the mechanisms by which natural (aprotinin) or synthetic antifibrinolytics (sigma-amino-caproic acid, tranexamic acid) exert their effects have been difficult to define. Nonetheless, all three substances appear to be effective in the treatment or in the prevention of excessive bleeding associated with cardiac surgery. However, the administration of these drugs should not attempt to replace meticulous surgical and anaesthetic care. In particular, the importance of an appropriate transfusion practice cannot be overemphasized. The efficient use of these, sometimes expensive, drugs must take into account not only the initial cost, but also the short- and long-term economic consequences for the health care provider of using, or not using, a given medication. Unfortunately, the comprehensive data on which authoritative conclusions may be reached are not yet available. Pending availability of these data, the present use of antifibrinolytics at the Montreal Heart Institute is the following: (1) patients undergoing elective primary myocardial revascularization or valve surgery do not receive prophylactic antifibrinolytics; (2) patients undergoing repeat myocardial revascularization, repeat valve surgery, or primary or repeat combined procedures, receive prophylactic sigma-aminocaproic acid; (3) sigma-aminocaproic acid may be used to treat excessive chest drainage in the postoperative period; (4) the prophylactic and the therapeutic uses of low doses of aprotinin are currently under investigation.

Aminocaproic Acid↗
PubMed1991

The stratification of cardiac surgical procedures according to use of blood products: a retrospective analysis of 1480 cases.

The use of blood products in 1480 consecutive cases of adult cardiac surgical procedures over a period of 15 mth was studied retrospectively using the database of the Department of Anaesthesia of the Institut de Cardiologie de Montréal. Use of blood products was compared in patients having (1) coronary artery bypass grafting, (2) valvular surgery, (3) or a combination of 1 and 2. First operations were compared with reoperations. Overall, the use of homologous blood products was greatest in patients of Group 3, intermediate in patients of Group 2, and smallest in patients of Group 1. Reoperations were associated with an increase in intraoperative transfusion of packed red blood cells, but postoperative chest drainage was similar to first operations. When all blood products (packed red blood cells, fresh frozen plasma and platelets) were taken into consideration, patients undergoing primary CABG or valve surgery were the least exposed to homologous blood donors (five and six units transfused respectively). Repeat CABG was associated with an intermediate exposure to homologous blood products (eight units). Finally, primary and repeat combined procedures, and repeat valve surgery were associated with the greatest exposure to foreign blood products (10, 13 and 10 units respectively). The data presented in this study provide a rational basis for stratification of procedures according to the expected use of blood products, particularly in view of future studies which may be planned to examine the efficiency of blood conservation strategies.

Aged↗
PubMed1990

Rapid induction sequence with vecuronium: should we intubate after 60 or 90 seconds?

The purpose of the study was to determine intubating conditions after administration of either succinylcholine or vecuronium in a rapid induction sequence. Patients received either succinylcholine 1.5 mg.kg-1 (Groups I and II) after d-tubocurarine 0.05 mg.kg-1 four minutes earlier, or vecuronium (Groups III and IV) in an initial dose of 0.01 mg.kg-1 followed four minutes later by 0.1 mg.kg-1. In Groups I and III an apnoeic delay of one minute was allowed before intubation whereas in Groups II and IV the delay was 90 sec. There was no significant difference in intubating conditions between Groups I and IV. Intubating conditions in Group III (vecuronium-delay of one minute) were statistically worse than in any of the three other groups. A delay of 90 sec after succinylcholine improved intubating conditions in male patients. Considering that intubating conditions obtained after 90 sec in patients given a priming sequence with vecuronium (Group IV) were not different from those obtained 60 sec after succinylcholine (Group I), the authors conclude that vecuronium is an acceptable alternative for rapid tracheal intubation. In the doses used in this study, intubating conditions 60 sec after vecuronium were unacceptable for rapid induction of anaesthesia.

Adult↗
PubMed1990

Occurrence of gastroesophageal reflux on induction of anaesthesia does not correlate with the volume of gastric contents.

In an attempt to explain the discrepancy between the high number of patients said to be at risk of aspiration pneumonitis and the low reported incidence of this anaesthetic complication, 100 ASA physical status I-II elective surgical patients were studied. The volume of fluid present in the stomach at the time of induction of anaesthesia was correlated with gastroesophageal reflux (GER) detected by visual inspection of the pharynx and by continuous measurement of upper oesophageal pH. Mean gastric volume was 30 +/- 28 ml (range 0-210 ml). Gastric fluid volume greater than or equal to 0.4 ml.kg-1 at pH less than or equal to 2.5 was present in 46 patients. No GER was detected during induction of anaesthesia in our sample of 100 patients. Furthermore, patient age, duration of preoperative fasting, body mass index, cigarette smoking, alcohol consumption, preoperative anxiety, and a history of preoperative GER were not correlated with significant modifications of gastric volume or pH. We conclude that the low incidence of aspiration pneumonitis in elective surgical patients may be explained in part by the very low risk of GER, despite gastric fluid volumes of more than 0.4 ml.kg-1 in a high proportion of this patient population.

Adult↗
PubMed1990

Pyloromyotomy of Ramstedt: experience of a nonspecialized centre.

In a general hospital over a period of 6 years 57 infants with congenital hypertrophic stenosis underwent a Ramstedt pylorotomy. In most cases a surgical resident-in-training performed the operation under the direct supervision of a general surgeon. There were no complications of anesthesia, no deaths and no substantial morbidity. The majority of infants left the hospital within 48 hours. The results in this series compared favourably with those reported from more specialized centres.

Clinical Protocols↗
PubMed1989

Decreasing the toxic potential of intravenous regional anaesthesia.

In an attempt to reduce the dose of local anaesthetic agent during intravenous regional anaesthesia (IVRA) of the upper limb, we have used a forearm tourniquet in 12 adult volunteers. The volume of the forearm venous system was predetermined angiographically. We performed IVRA with three solutions of lidocaine (0.25, 0.375, 0.5 per cent) administered in a volume equal to the forearm venous system. Angiographic results indicate that: a forearm tourniquet provides adequate vascular isolation; the volume of the forearm venous system can be correlated with body weight; the progression of the fluid in the venous system follows a pattern that is similar for all patients with the small veins of the distal forearm and proximal hand being filled last. With this technique, lidocaine 0.5 per cent resulted in a dose of 1.5 mg.kg-1 and provided excellent analgesia. Lower concentrations were unsatisfactory. We conclude that the use of a forearm tourniquet allows reduction of the local anaesthetic dose to a non-toxic level and thus increases the safety of IVRA.

Adult↗
PubMed1987

[Intestinal distention during elective abdominal surgery: should nitrous oxide be banished?].

High concentrations (70-80 per cent) of nitrous oxide (N2O) have been shown to cause distension of gas-containing distensible structures such as the intestines and are, for this reason, avoided by some during elective abdominal operations on the GI tract. We undertook this study to determine if N2O was responsible of a measurable change in intestinal diameter or of clinical difficulty in closing the abdomen in patients undergoing elective intestinal surgery of intermediate duration. Twenty patients scheduled for elective abdominal surgery were studied. Premedication and induction were identical in all patients. Maintenance of anesthesia in Group I was with enflurane in air/oxygen, and fentanyl. Patients in Group II received enflurane in N2O/oxygen, and fentanyl. FIO2 was 0.4 in both groups and monitored neuromuscular blockade with pancuronium was kept optimal throughout the operation. The surgeon was blinded as to the random distribution of patients to either group. Girth measurements at the level of the umbilicus were recorded before induction and after surgery. The circumferences of the terminal ileum and of the transverse colon were measured at the beginning and at the end of surgery. The surgeon was asked to rate the difficulty in closing the abdomen as 0 = none, 1 = slight, 2 = moderate, 3 = severe, 4 = impossible. Data were analysed using Student's paired t test, unpaired t test and Fisher's exact test. P less than 0.05 was considered statistically significant. There was no significant difference between groups in age, sex distribution, weight and duration of surgery (approximately 90 minutes in both groups).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗