Showing papers on "Hypoventilation published in 1997"

Central apnea and acute cardiac ischemia in a sheep model of epileptic sudden death

Abstract: The etiology of sudden death in patients with epilepsy remains unclear. Previous studies in a well-established sheep model of status epilepticus showed that more than one-third of the unsedated animals died within 5 minutes of seizure onset due to hypoventilation. The relative contributions of airway obstruction and central hypoventilation could not be determined because airway flow and respiratory effort were not monitored. In this study, status epilepticus was induced in unsedated sheep with tracheostomies monitored by electrocardiography, electroencephalography, arterial line, serial blood gases, and airway flowmeter. All 8 animals demonstrated central apnea and hypoventilation, which resulted in the death of 1 and contributed to the death of another. A third animal died of acute heart failure within 2 minutes of seizure onset, accompanied by a large septal myocardial hemorrhage, contraction bands, and signs of global cardiac ischemia. More subtle contraction bands, subendocardial hemorrhage, and signs of acute myocardial ischemia were seen in other animals as well, none of which died of cardiac causes. Malignant arrhythmia was not seen in any of the sheep. Central hypoventilation and apnea accompany generalized status epilepticus and may be an important cause of sudden death in epileptics. Acute cardiac failure may also be a cause of epileptic sudden death.

Impact of sleep in respiratory failure

Abstract: Sleep has a physiological influence on respiration, which can have major adverse effects on gas exchange in patients with respiratory insufficiency. These effects relate largely to a reduction in various stimulant inputs to the brainstem respiratory centre. Conditions that may be associated with sleep-related respiratory insufficiency range from pulmonary disorders (such as chronic obstructive pulmonary disease (COPD)), to central respiratory insufficiency (such as central alveolar hypoventilation), neurological and neuromuscular disorders (such as polio and muscular dystrophy), and thoracic cage disorders (such as kyphoscoliosis). All these conditions have in common the finding of hypoxaemia and hypercapnia, which become more pronounced during sleep. The relative hypoventilation, which is common to each condition, is due to varying combinations of an inadequate respiratory drive and an increase in the work of breathing. Management of respiratory insufficiency during sleep should be directed first at optimizing the underlying disorder, then at correcting hypoxaemia with controlled low-flow supplemental oxygen. Pharmacological therapy may be effective in some instances, but the choice of agent varies with the underlying disorder. Assisted ventilation is an important part of the management of advanced cases, and the recent development of intermittent positive pressure ventilation by nasal mask (NIPPV) has been an important advance in this area. Use of NIPPV during the night is associated with beneficial effects during the day, particularly improved awake gas exchange and respiratory muscle strength, in addition to less dyspnoea and improved quality of life. Electrophrenic pacing of the diaphragm is helpful in highly selected cases, particularly patients with central respiratory insufficiency and high quadriplegia, but is frequently complicated by the development of obstructive sleep apnoea.

Daytime mechanical ventilation in chronic respiratory insufficiency

Abstract: Chronic respiratory insufficiency (CRI) is associated with nocturnal hypoventilation. Treatment with noninvasive mechanical ventilation (NIMV) performed overnight relieves symptoms of hypoventilation and improves daytime blood gases in CRI. In order to test whether the efficacy of NIMV depends on it being applied during sleep, we conducted a prospective case-controlled study comparing daytime mechanical ventilation (dMV) in awake patients with nocturnal mechanical ventilation (nMV) given in equal quantities. We enrolled 34 clinically stable patients (age 56.1+/-12.1 yrs, 20 females, 14 males) with CRI due to restrictive lung and chest wall disorders and neuromuscular disease. Using a prospective case-control design, matched subjects were allocated alternately to dMV and nMV. After 1 month of NIMV there was considerable symptomatic improvement in both dMV and nMV patients. There were no significant differences between groups in the improvement in daytime arterial carbon dioxide tension (Pa,CO2) (dMV from 7.5+/-0.6 to 5.7+/-0.6 kPa; nMV from 7.2+/-0.5 to 5.8+/-0.5 kPa, p<0.0001) and during the unassisted spontaneous night-time ventilation in terms of transcutaneous Pa,CO2 (dMV from 8.4+/-1.2 to 6.6+/-0.7 kPa; nMV from 8.2+/-1.2 to 6.8+/-0.5 kPa, p<0.0001). We conclude that in many respects, when compared to nocturnal mechanical ventilation, daytime mechanical ventilation in awake patients is equally effective at reversing chronic respiratory insufficiency. Since long-term safety issues were not addressed in this study, we recommend that nocturnal mechanical ventilation should remain the modality of choice for noninvasive mechanical ventilation.

Nocturnal respiratory failure as an indication of noninvasive ventilation in the patient with neuromuscular disease.

Abstract: Patients with neuromuscular disease may suffer from nocturnal respiratory failure despite normal daytime respiratory function. The physiological reduction in muscle tone during sleep may be life-threatening in a patient with impaired muscle strength. Nocturnal respiratory failure may occur in patients with the postpolio syndrome, amyotrophic lateral sclerosis, myasthenia gravis, myotonic dystrophy, and muscular dystrophy. Diagnosis of obstructive, central and mixed apneas, hypopneas, and hypoventilation is best made using polysomnography. Therapeutic options include noninvasive ventilation such as continuous positive airway pressure, bilevel positive airway pressure, intermittent positive pressure ventilation and, rarely, tracheostomy, oxygen, or protriptyline. Evaluation by a sleep specialist should be initiated in any neuromuscular patient with nocturnal symptoms such as air hunger, intermittent snoring or breathing, orthopnea, cyanosis, restlessness, and insomnia. Daytime symptoms may include morning drowsiness, headaches and excessive daytime sleepiness. Polycythemia, hypertension, and signs of heart failure may also be seen. Effective treatment is available, and may improve the quality of life, and possibly increase survival.

Anaesthetic management of a patient with Leigh's syndrome.

Abstract: Leigh’s syndrome, a progressive neurodegenerative disorder of infancy and childhood, is clinically charactenzed mainly by developmental delay, nervous system dysfunction and respiratory abnormalities such as aspiration, wheezing, breathing difficulties, gasping, hypoventilation and apnoea. Acute exacerbation and respiratory failure may follow surgery, general anaesthesia or intercurrent illnesses. Hyperlactataemia is variably present. Histopathological findings include necrosis, vascular proliferation, astrocytosis and demyelination of several brain areas. We present a 30-month-old patient with Leigh’s syndrome anaesthetized for extracorporeal shockwave lithotripsy, and describe the anaesthetic considerations. Leigh’s syndrome was diagnosed at five months of age based on failure to thrive, lethargy, hypotonicity, choreo-athetosis and lactic acidaemia, with basal ganglia hypodense areas demonstrated by brain computerized tomographic scan. Muscle pyruvate dehydrogenase complex and NADH-coenzyme Q oxidoreductase activity were 25% and 13% of control. No preoperative respiratory symptoms or signs were present. Preoperative fasting lasted two hours and gastric aspiration was negative. Anaesthesia was induced with ketamine and midazolam im, and N2O in oxygen, and maintained with propofol and N2O. No volatile anaesthetics were used. Intravenous fluids given were 1/2 normal saline and glucose 5% administered. Besides laryngospasm dunng anaesthetic induction, relieved by sublingual succinylcholine injection, the perianaesthetic course was uneventful. The lungs were mechanically ventilated and lithotripsy was performed. No adverse sequelae have occurred, and the patient was discharged one day later. Perioperative management of patients with Leigh’s syndrome requires cautious attention to the metabolic, neurological and respiratory aspects of the disease, and appropriate selection of anaesthetic drugs.

Reversal of Intractable Acute Severe Asthma by First-Trimester Termination of Pregnancy

Abstract: A 19-year-old woman was admitted with acute severe asthma in her eleventh week of pregnancy. Despite vigorous therapy, severe hypoventilation and hypoxemia persisted with mechanical ventilation. Termination of pregnancy resulted in dramatic improvement in airflow. Her course was complicated by pneumonia, barotrauma, and atelectasis accompanying her moribund state. Although she immediately improved following abortion (within 2 hr, peak airway pressure fell from > 70 to 38 cmH2O, without change in plateau pressure), superimposed morbidities improved more slowly, and the patient made a complete recovery. The mechanism accounting for this observation is unknown but the rapid improvement following abortion suggests that increased bronchomotor tone predominated inflammatory changes in causing flow limitation.

Nasal ventilation in pregnancy: treatment of nocturnal hypoventilation in a patient with kyphoscoliosis

Abstract: The management of a young woman with congenital kyphoscoliosis, who developed symptomatic nocturnal hypoventilation during the third trimester of pregnancy, is described. Nasal intermittent positive pressure ventilation (NIPPV) was safely and effectively used to correct nocturnal hypoxaemia and hypercapnia from the 30th-36th week of gestation, when a healthy boy was delivered by Caesarean section. Following delivery, the mother no longer required NIPPV and returned to her prepregnancy level of activity.

Chronic Intermittent in utero Exposure to Morphine: Effects on Respiratory Control in the Neonatal Guinea Pig

Abstract: This study was done to determine if chronic intermittent in utero exposure to morphine (MOR) during the last half of gestation results in hypoventilation and decreased ventilatory sensitivity to CO2 in the neonate. Pregnant guinea pigs were randomly assigned to once-daily treatment with saline and 1.5, 5.0, or 15.0 mg/kg MOR. Neonates were studied for 3 weeks. Prenatal exposure to 5.0 and 15.0 mg/kg MOR significantly increased neonatal minute ventilation and central inspiratory drive on day 7 while breathing room air or 5% CO2. The increase in minute ventilation was part of a withdrawal syndrome that included increased locomotor activity, but was not due to an increase in metabolic rate or sensitivity to CO2. We conclude that neonatal guinea pigs exposed once daily to MOR during the last half of gestation hyperventilate during the 1st week after birth. These changes are neither permanent nor followed by hypoventilation or depressed sensitivity to CO2.

Hypercarbia During Tracheostomy in the Head-Injured Patient: Compariscon of Percutaneous Endoscopic, Percutaneous Doppler and Standard Tracheostomy

Abstract: Purpose: Bronchoscopy during percutaneous tracheostomy may cause a significant increase in pCO2 due to hypoventilation. The clinical relevance of this hypercarbia is unclear. We examined the effects of procedure-induced hypercarbia on cerebral perfusion during percutaneous endoscopic (PET), percutaneous doppler (PDT), and standard surgical tracheostomy (ST). Methods: Three patients with indwelling radial artery catheters and intracranial pressure monitors underwent PET, PDT, or ST in the Intensive Care Unit. Intermittent arterial blood gases were obtained throughout each procedure. Simultaneous measurements of mean arterial pressure (MAP), intracranial pressure (ICP), and cerebral perfusion pressure (CPP=MAP-ICP) were recorded. Results: All tracheostomies were successfully performed with no technical complications. No episodes of hypoxia occurred during the procedures. Conclusions: Bronchoscopy during percutaneous endoscopic tracheostomy leads to hypoventilation, hypercarbia, and respiratory acidosis. In the head-injured patient, this hypercarbia does result in a marked increase in ICP and a related decrease in CPP to ischemic ranges. Tracheostomy (either standard surgical or percutaneous using the doppler ultrasound to position the endotracheal tube) can be safely performed in the head injured patient without adversely affecting cerebral perfusion. The potential for hypoventilation should be considered when choosing the method of tracheostomy in the head-injured patient where hypercarbia may be detrimental to cerebral hemodynamics. CORRESPONDENCE Patrick M. Reilly, M.D. Division of Trauma and Surgical Critical Care Department of Surgery University of Pennsylvania School of Medicine 3440 Market Street First Floor Philadelphia, PA 19104 (215) 662-7320 (215) 349-5917 FAX E-mail: reillyp@mail.med.upenn.edu

[The post-poliomyelitis syndrome--a real complication. A poliomyelitis material from the Haukeland hospital].

Abstract: Over a four-year period, all in-patients at our department with the diagnosis of polio-sequelae were clinically examined for development of new neuromuscular deficit. 19 out of 125 patients (15%) had developed a postpolio syndrome. All 19 had acquired additional functional deficit and 17 new, localized pareses. Five patients had developed polio-related hypoventilation. The mean time from acute poliomyelitis to debut of the post-polio syndrome was 39 years. The post-polio syndrome occurred in patients with severe pareses in the acute stage, but was not related to age, sex or specific epidemic. Most of the 106 other patients had similar subjective complaints but did not have any clinical signs indicating new neuromuscular deficit. 67 of these patients had tendinitis and/or myalgia and 83 had chronic pain. Whereas many patients have progressive symptoms many years after poliomyelitis, only a minority develop the post-polio syndrome.

[Increased physical activity due to intermittent self-ventilation in chronic respiratory insufficiency].

Abstract: BACKGROUND Nocturnal mechanical ventilation (NMV) can reduce symptoms of hypoventilation and improve gas exchange in patients with chronic respiratory failure but there is no data concerning the impact of nocturnal mechanical ventilation on daily activity. We prospectively measured daily activity as judged by total steps per day. PATIENTS AND METHODS Thirty stable patients (17 men, mean age 55.2 years, pCO2: 62.3 +/- 9.0 mmHg) with chronic respiratory failure. DIAGNOSIS Kyphoscoliosis (n = 11), COLD (n = 7), neuromuscular diseases (n = 6), post-tbc sequelae (n = 6). Applying a pedometer over a 7 day period before and 3 months after initiating nocturnal mechanical ventilation the steps per day were counted. We also obtained arterial blood gases and applied the St. George's Respiratory Questionnaire (scoring range from 0 = complete health to 100 = worst possible). RESULTS AND CONCLUSIONS The daily activity in patients with hypercapnic respiratory failure as judged by the total amount of steps per day increased by 120% after 3 months of nocturnal mechanical ventilation (from 1606.9 +/- 1341.3 to 3535 +/- 1813.8 steps per day, p < 0.0001). This was associated with a significant improvement in daytime blood gases and quality of life (QoL) as judged by questionnaire (total score: from 61.3 +/- 14.9 to 48.3 +/- 18.7, p = 0.0006). However no correlation between steps per day and QoL was found.

Postnatal development of breathing control

Abstract: Respiratory movements already occur in the fetus together with low amplitude high frequency EEG. During birth external stimuli drive respiration, supported by the development of hypercapnia, hypoxia and acidosis. The thresholds of the chemosensitive systems adapt during the first hours and days of life (CO2 sensitivity) or weeks (hypoxic sensitivity). In 180 healthy infants between 5 days and 18 months of age we performed respiratory CO2-responses during NREM-sleep and studied the immediate response to inhalation of 60% oxygen (Dejours test) as well as in 8 children with congenital central alveolar hypoventilation syndrome (CCHS) and 15 infants who experienced an apparently life-threatening event (ALTE). Infants older than 2 weeks had a mean PCO2 of 40-42 mmHg, the slope of the CO2-response showed no age trend and was found in the range of adults with a 22-38% increase in ventilation per Torr increased PCO2. Preterm infants had a significant lower CO2-response (16 vs. 33%) until they reached their estimated normal birth date. In the ALTE group the CO2-response was suppressed to 17%. Children with CCHS did not respond to CO2 by increasing their ventilation, even after years. The response to hyperoxia as a measure of peripheral chemoreceptor activity decreased from a 31% initial inhibition of ventilation at 1 month to 20% at one year. Our results indicate that temporary or lasting reduction or lack of the respiratory CO2 sensitivity may cause apneic events or hypoventilation. Different slopes of CO2- and hyperoxic responses in very young infants compared to older ones favour the occurrence of oscillations in the control of breathing such as periodic breathing during sleep.

[Noninvasive ventilation of a 4-year-old boy with severe central late onset hypoventilation syndrome].

Abstract: BACKGROUND In the literature we found only five reports about noninvasive ventilation in cases with central hypoventilation syndrome. PATIENT AND METHOD We report about a 4-year-old boy with severe late onset hypoventilation syndrome. During an interval of 3 months with nasal mask ventilation during sleep he showed an excellent cognitive and statomotoric development. After this time, he needed a noninvasive ventilation with a negative pressure system. RESULTS AND DISCUSSION In our opinion, noninvasive nasal mask ventilation is a modern method in the treatment of patients with central hypoventilation syndrome. Tracheotomy is only necessary during the first year of life.

[Follow-up of intermittent self-ventilation (ISB). Mortality and causes].

Abstract: BACKGROUND: Intermittent positive pressure ventilation (IPPV) has an impact on morbidity and survival in patients with chronic respiratory failure. We analyse the causes of death in relation to the disease, the age, the effectiveness of and the compliance with IPPV. PATIENTS: The course of 108 patients, who were on IPPV for a mean of 24 (SD +/- 21) months, is analysed. RESULTS: Twenty-seven patients die (7/7 AIS, 2/17 muscular dystrophy, 8/45 kyphoskoliosis and TB sequelae, 2/7 other neurological diseases, 6/16 COPD bronchiectasis, 1/1 fibrosis of the lang). The cause of death is in 21 hypoventilation or respiratory infection due to progressive disease (9 patients), air leakage after occlusion of tracheostoma (2 patients), bronchitis (6 patients), discontinuation of IPPV (3 patients). Two patients develop pulmonary failure (atypical mycobacteriosis and asbestosis, pulmonary embolism). Non-pulmonary causes of death are present in 2 (rupture of aortic aneurysm, pleural carcinosis). CONCLUSIONS: A safe interface for IPPV is needed for longer survival. An efficient system of home-care has to be developed.

Sedation and anaesthesia outside the OR.

Abstract: The sedation of paediatric patients is associated with serious risks such as hypoventilation, apnoea, airway obstruction, and cardiopulmonary impairment; these risks should be avoided or accurately and rapidly diagnosed and appropriately treated. Appropriate management may include ventilation by mask and cardiopulmonary resuscitation, which require special training and skills.

Primary alveolar hypoventilation in adulthood

Abstract: BACKGROUND Central alveolar hypoventilation in an adult is characterized by dysfunction of the respiratory center in the brainstem and is very rare, seen mostly secondary to neurological lesions of the brainstem. CASE DESCRIPTION We report a 48-year-old man with primary alveolar hypoventilation associated with marked cardiac arrhythmias and hemodynamic changes. Arterial blood gas analysis revealed daytime hypoxemia and hypercapnia not explained by normal pulmonary results. All night polysomnography showed sleep fragmentation following repetitive central apneas and hypoventilation with marked hypoxemia and the lowest saturation in REM sleep. Severe nocturnal hypoxemia was accompanied by marked hypercapnia. Premature ventricular complexes occurred associated with nocturnal hypoxemia in NREM sleep while sinus arrest of up to 11.3 s were only seen associated with hypoxemia in REM sleep. Pulmonary arterial pressures were normal when the patient was awake with marked increases in pulmonary arterial pressures associated with hypoventilation and changes in arterial oxygen saturation with the patient was asleep. CONCLUSION Nasal positive pressure ventilation was effectively able to treat central apneas and hypoventilation, nocturnal hypoxemia and cardiac arrhythmias were no longer observed. Also, daytime arterial blood gases were normal with nocturnal nasal mechanical ventilation.