Safety and efficacy of a new device for inducing ejaculation in men with spinal cord injuries.

STUDY DESIGN: Prospective case series. OBJECTIVES: Male infertility is a common sequela of spinal cord injury (SCI). Fatherhood is a goal in this group of young patients; however, most are anejaculatory. Penile vibratory stimulation is recommended as the first line of treatment for this condition. Our study evaluated the safety and efficacy of a new device designed to induce ejaculation in these patients. SETTING: The Miami Project to Cure Paralysis, Miami, FL, USA. METHODS: The Viberect-X3 (Reflexonic, Frederick, MD, USA) was applied to 30 consecutive anejaculatory men with SCI whose level of injury was T10 and rostral. RESULTS: The ejaculatory success was 77% (23/30). No adverse events occurred, and there were no malfunctions of the device. CONCLUSION: In this first report on the efficacy of the Viberect-X3 for treatment of anejaculation in men with SCI, we conclude that the device is safe and effective for inducing ejaculation in men with SCI. Recommendation of the Viberect-X3 versus other devices intended for this purpose should not be made until randomized controlled trials are performed.

The influence of intravenous anaesthetics on enflurane-induced central nervous system seizure activity.

This study assesses the effects of agents commonly used in anaesthesia on enflurane-induced seizure threshold and on established seizure activity, during steady state enflurane anaesthesia. EEG seizure activity was monitored in cats from chronic cortical and subcortical recording sites. Diazepam, thiopentone, methohexitone and ketamine all enhanced established EEG seizure challenge. This latter effect was most evident under conditions of lowered PaCO2. The effects of these intravenous agents on established enflurane seizure patterns exceeded in duration the expected EEG effect of the agent when used alone. The limited number of experiments, however, precluded statistical verification of our findings. The similarities between centrencephalic minor motor seizures and enflurane seizure pattern in terms of EEG and convulsive expression, including drug response, are noted.

Use of a Doppler ultrasound stethoscope for intercostal nerve block.

Two cases with rib injuries are reported where intercostal nerve block without rib palpation was safely and successfully performed on six separate occasions using a Doppler blood-flow detector ultrasound stethoscope. A third case studied by a radiologist using a pulsed Doppler flowmeter, determined the source of the Doppler signals as originating from the intercostal artery. The significance of these findings is discussed.

Surgery in Jehovah's Witnesses.

This is a retrospective study of the outcome of surgical procedures in patients who were Jehovah's Witnesses. Over a 75-month period, 58 Jehovah's Witness patients had 78 surgical procedures at the Vancouver General Hospital. Three patients had preexisting anaemia of less than 100 g.L-1 haemoglobin. Postoperative haemoglobin concentration decreased below 50 g.L-1 in three patients. One patient had a postoperative haemoglobin of 34 g.L-1 (haematocrit 10.1 per cent) and survived. One patient died from uncontrollable postoperative haemorrhage. Perioperative morbidity was not uncommon, including significant hypotension (eight cases), cardiac arrhythmias (six), myocardial ischaemia (three), excessive bleeding (four), postoperative nausea or syncope (four), and wound or urinary tract infection (four).

The cardiovascular effects of ketamine in hypotensive states.

Ketamine was found to raise the systemic arterial blood pressure but not necessarily the perfusion in hypovolaemic states. However, in hypotensive states of short duration from endotoxin treatment, it improved the haemodynamics with increase in both the perfusion and the systemic pressure. The implications of these observations for clinical situations were discussed.

Central nervous system effects of bupivacaine.

The central nervous system and concurrent cardiovascular effects of bupivacaine infusion were studied in cats. It was possible to block cortical E.E.G. desynchronization resulting from a sensory stimulus with bupivacaine. The earliest subcortical change that occurred was rhythmic activity in the amygdala and later in the hippocampus. Occasionally, this activity appeared simultaneously in both these sites. Diazepam pretreatment raised the seizure threshold of bupivacaine. Diazepam was also effective in terminating established seizure activity resulting from bupivacaine. All animals pretreated with diazepam (Valium) or diazepam solvent developed cardiac dysrhythmias durind bupivacaine infusion. The possible clinical significance of the interaction of bupivacaine and diazepam solvent is considered.

Anaesthetic implications of calcium channel blockers.

Clinical uses of calcium channel blockers are expanding. In addition to the established uses in patients with arrhythmias, angina pectoris or hypertension, newer and to some extent investigational uses indicate widespread application. For instance, their use has been reported in hypertrophic cardiomyopathy and cold cardioplegia, as well as in pulmonary hypertension, antiplatelet therapy, asthma, achalasia and oesophageal spasm, increased intraocular pressure and in cerebral vasospasm. Their use in obstetrical practice has been proposed. Thus, the presentation of a patient who is treated with calcium channel blockers and who requires anaesthesia will become more common. Calcium channel blockers may, under certain circumstances, potentiate haemodynamic and MAC depressive effects of inhalation agents. There is also evidence that the effects of neuromuscular blocking agents may be potentiated. The anaesthetist should be aware that the potential for interactions exists with digoxin, propranolol, quinidine, theophylline or dantrolene. Of interest and some significance are the anaesthetic implications of pathophysiological alterations that can be induced by calcium channel blockers, by affecting lower oesophageal tone, intracranial hypertension, bronchomotor tone (asthma), muscular dystrophy, neuromuscular function, hypoxic pulmonary vasoconstriction, malignant hyperthermia, inhibition of platelet aggregation and hyperkalemia. Despite these significant potential anaesthetic implications and because, at this time, in some instances withdrawal has clearly demonstrated increase in the signs of myocardial ischaemia, it would not seem necessary to recommend preoperative discontinuation of calcium channel blocker medication in patients presenting for anaesthesia. It is, however, appropriate that there is a high index of awareness of potential problems, unless there is some modification in inhalation anaesthetic concentrations and neuromuscular blocker dosage. Monitoring of cardiovascular and neuromuscular functions is essential. Calcium channel blockers would appear to be currently the drugs of choice for angina pectoris, arrhythmias or hypertension in patients with associated chronic obstructive pulmonary disease.

Complications of and improvements to breathing circuit monitors for anesthesia ventilators.

Despite significant improvements in the safety of anesthetic equipment in recent years, disconnection in the patient breathing circuit remains one of the most common types of preventable anesthetic mishaps. Many currently available breathing-circuit monitors cannot reliably detect several hazardous conditions in the breathing circuit. An improved breathing circuit monitor has been developed that reliably detects realistic simulations of many hazardous conditions. The software algorithm in this monitor stores the normal pressure waveform in the patient circuit, evaluates the ongoing waveform in terms of sets of absolute and relative criteria, and warns the operator when such criteria are not satisfied. A comprehensive technical and clinical evaluation is underway.

Prediction of the need for postoperative mechanical ventilation in myasthenia gravis: thymectomy compared to other surgical procedures.

In a recent report Leventhal, Orkin, and Hirsh described a scoring system felt to be of value in predicting the need for postoperative mechanical ventilation in patients with myasthenia gravis undergoing thymectomy. Leventhal, et al. identified four risk factors felt to have predictive value, namely: (1) duration of myasthenia gravis greater than or equal to 6 years, (2) chronic respiratory disease, (3) dose of pyridostigmine greater than or equal to 750 mg per day, and (4) vital capacity less than or equal to 2.9 litres. Forty-six patients with myasthenia gravis who received 68 general anaesthetics were studied retrospectively. They represented the past 10 years' anaesthetic experience with myasthenia gravis at the Vancouver General Hospital. The patients were divided into two groups: (1) those who underwent thymectomy, and (2) those who underwent procedures other than thymectomy. Using the risk factors of Leventhal, et al., a predictive score was assessed for each patient; the time of postoperative tracheal extubation was also noted for each patient. From this study it was concluded that the scoring system proposed by Leventhal, et al. may have been of some value in predicting whether or not a particular patient undergoing thymectomy was likely to need ventilation postoperatively. In 41 myasthenics who had procedures other than thymectomy, however, this scoring system was found to be of no value.

A comparative evaluation of cimetidine and sodium citrate to decrease gastric acidity: effectiveness at the time of induction of anaesthesia.

Patients coming for elective surgery were randomly assigned to one of three treatment groups: control, cimetidine 300 mg orally two hours pre-operatively, or sodium citrate 0.3 M solution 30 ml orally, given as the patient was leaving the ward for the operating room. Each group consisted of 15 patients. This study reconfirms the average 26 per cent risk of significant aspiration in patients, coming for elective surgery, who have not received an agent intended to decrease gastric acidity or to decrease volume of gastric content. Sodium citrate is effective most of the time (87 per cent) in decreasing gastric acidity but is associated with a large mean volume (40.8 ml) of aspirate. From the results of this study cimetidine appears to be the preferable agent to use because it is completely effective in decreasing gastric acidity but does not increase the mean volume (17.0 ml) of the aspirate. Cimetidine appears to be an excellent agent to use as a preventative measure against aspiration during the induction of anaesthesia. Sodium citrate is a reasonable alternative if there is a contraindication to the use of cimetidine. However, these agents should be regarded only as adjuncts in the prevention of aspiration of gastric contents at the time of induction of anaesthesia.

Protection of the brain from hypoxia: a review.

A functional classification of hypoxia of the brain has been presented and some of its significant aspects have been discussed. Mechanisms of protection from hypoxia of the brain were reviewed under the headings of prevention, hyperventilation, hypothermia and protection by barbiturates. In prevention of hypoxia of the brain, avoidance of factors producing a fall in cerebral perfusing pressure was emphasized. Hyperventilation is not advised unless one can readily measure regional cerebral blood flow. In the operating room, normocarbia or slight hypocarbia is recommended. Animal studies indicate a protective role of barbiturates in ischaemic hypoxia of the brain. However, it should be emphasized that, at present, hypothermia is the only established means of protection against hypoxia of the brain in man, when it is induced prior to the hypoxic insult. The evidence for protection by barbiturates has been found only in experimental animals. If one can extrapolate the results of studies in animals to man, then potential benefits would be expected in clinical stroke, cardiac arrest, in operations on the carotid artery and in head injury.

Intermittent mandatory ventilation and controlled mechanical ventrilation without positive end-expiratory pressure following cardio-pulmonary bypass.

In a group of 18 male patients undergoing coronary artery bypass grafting with cardiopulmonary bypass, the overall incidence of post-operative atelectasis was 60%. Nearly three-quarters occurred during anaesthesia. After operation there was no difference whether CMV or IMV without PEEP was provided overnight. Atelectasis already present did not improve and further atelectasis occurred. A role for IMV is not excluded, since it facilitates the use of PEEP. Many factors operate and interact to provoke atelectasis during anaesthesia, which increases post-operative morbidity. Many of these factors are prevertible or reversible if their physiological basis is understood. Optimal post-operative ventilation should be tailored to the needs of the individual patient and demands close co-operation between anaesthetist and surgeon.

Modification by preoperative beta-blockade of the renin response to infrarenal aortic cross-clamping.

The activity of the renin-angiotensin system was measured before, during, and after infrarenal aortic cross-clamping in 13 patients. Five of the patients studied were taking propranolol preoperatively and formed a subgroup. Intraoperative blood loss, volume of crystalloid and colloid infused, haemodynamic parameters and urine output were similar for the two groups. In eight patients who were not taking propranolol mean plasma renin activity was 2.24 ng . ml-1 . hr-1 prior to induction, 3.78 ng . ml-1 . hr-1 during surgery prior to cross-clamping and 4.42 ng X ml-1 X hr-1 15 minutes after the aorta was cross-clamped (increases not statistically significant). Mean plasma renin activity measured ten minutes prior to release of the cross-clamp (5.02 ng X ml-1 . hr-1), 15 minutes after clamp release (5.47 ng X ml-1 X hr-1), and 30 minutes after reaching the recovery room (5.84 ng X ml-1 X hr-1) were significantly greater than preinduction levels. Four patients developed postoperative hypertension (mean blood pressure greater than 120 mmHg); there was not a correlation between the elevated plasma renin activity observed postoperatively and the occurrence of postoperative hypertension. The five patients taking propranolol had a markedly attenuated renin activity response during and after surgery; the mean plasma renin activity was less than 1.5 ng X ml-1 X hr-1 at all sampling times. Two of these five patients did develop postoperative hypertension. It is concluded that surgery involving infrarenal aortic cross-clamping is associated with increased plasma renin activity with peak levels occurring postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Hospital admissions from the Surgical Day Care Centre of Vancouver General Hospital 1977-1987.

The admissions to Vancouver General Hospital from its Surgical Day Care Centre were reviewed for the period 1977 to 1987. The overall mean rate of admission for the period was 0.28 per cent, for surgically-related admissions 0.22 per cent and for anaesthesia-related admissions 0.07 per cent. The principal reasons for surgery-related admissions were postoperative bleeding, complications, the need for further surgery, the requirement for prolonged postoperative care, and pain. Urology had a particularly high percentage of admissions compared with its workload, because of the diagnostic nature of much of the work. Anaesthesia-related admissions included "syncope," lack of an accompanying adult, aspiration pneumonitis and coincident acute disease. Twelve of the 14 patients admitted with syncope had surgery in the afternoon and had received less than ideal amounts of intravenous fluid. Seven of the 12 ASA physical status II patients admitted had an admission diagnosis related to the coincident disease.

Detection of interruptions in the breathing gas of ventilated anaesthetized patients.

Interruption of the breathing gas to a ventilated anaesthetized patient due to accidental disconnection or anaesthesia system malfunction may have serious consequences if not detected quickly. A series of tests which covers the range of foreseeable mechanical problems was developed and used to test the performance of three breathing gas interruption monitors, two commercially available and one developed at Vancouver General Hospital. The tests were designed to evaluate the performance of monitors as installed on anaesthesia systems under a variety of failure conditions, including endotracheal tube disconnection with and without occlusion of the opening, kinks in the inspiratory and fresh gas hoses, disconnection of the fresh gas hose, leaks in the breathing circuit, excessive high or low pressure in the scavenging circuit, continuing high breathing circuit pressure, and kinks in the circuit pressure sensing hose. Ability to detect both significant changes in ventilation variables and faults existing at initiation of ventilation were also tested over a representative range of ventilator and patient variables using circle, coaxial and paediatric circuits. Only complete endotracheal tube disconnections with no obstruction of the opening were reliably detected by all three monitors. A commercial monitor with a single fixed-threshold alarm level also detected fresh gas interruptions in circle and adult coaxial circuits, but failed to alarm in response to any other fault condition. A monitor with selectable pressure thresholds and high, low, and continuing pressure limits detected just under half of the fault conditions. A microprocessor-based monitor developed at Vancouver General Hospital detected and correctly identified roughly 80 per cent of the faults. The series of tests forms the basis for a Canadian Standards Association Preliminary Standard (Z168.10) and will allow hospitals to test the performance of breathing gas interruption monitors in use in their institutions. Comments on the test series are solicited.

Magnesium and the anaesthetist.

Magnesium plays an important role as a cofactor in many of the body's critical functions and reactions. A deficiency or excess of extracellular magnesium can produce significant signs and symptoms. Hypomagnesaemia is a common finding in hospitalised patients, especially those in critical care areas. Anaesthetising hypomagnesaemic patients may exacerbate pre-existing cardiovascular disease and increase the risk of perioperative dysrhythmias. A low serum magnesium level usually suggests a total body deficiency of magnesium. Treatment of magnesium deficiency is by parenteral magnesium and should be instituted prior to surgery. Hypermagnesaemia is often iatrogenic and is more likely in patients with renal dysfunction who are receiving oral or parenteral magnesium. The specific antidote is intravenous calcium. Anaesthetised patients with high serum magnesium levels are at risk from hypotension, potentiation of non-depolarising neuromuscular blockers, postoperative respiratory failure and cardiac arrest.

A survey of obstetric anaesthesia practice in British Columbia.

Hospitals and anaesthetists in British Columbia were surveyed by means of questionnaires to assess patterns of obstetric anaesthesia practice, qualifications and numbers of obstetric anaesthesia personnel, hospital obstetric facilities and facilities and protocols for neonatal resuscitation. It was apparent that a large proportion of the obstetric anaesthesia service in this province was being provided by physicians who were not trained, nor certified, as anaesthesia specialists. Preanaesthetic assessment in the obstetric units differed in attitude and practice from the standards expected in the general operating rooms. There was also in community hospitals a significant incidence of failure to follow certain accepted safe practices (in obstetric patients), such as preinduction hydration and oxygenation, cricoid pressure during intubation and prevention of aortocaval compression. However, administration of general anaesthesia without endotracheal intubation, was rare in this survey. Post-anaesthetic recovery facilities in obstetric units were conspicuously deficient, even in the larger hospitals. The majority of community hospitals lacked written protocols for neonatal resuscitation; and the number of institutions reporting that the neonatal heart rates and temperatures were not routinely monitored is of concern. It is recommended that minimum standards for training in obstetric anaesthesia should be clearly defined; and provision should be made for revision and upgrading of knowledge and skills for physicians practicing anaesthesia in smaller community hospitals.