Biomedical subjects

S G Saisch

Publications and source records attributed to S G Saisch.

4 recordsLinked to original sources

PubMed1996

Patients with acute hyperventilation presenting to an inner-city emergency department.

We studied 23 consecutive patients with acute hyperventilation presenting to an inner-city emergency department, diagnosed on clinical grounds by the attending physician and confirmed by arterial blood gas values in 5 patients. An organic basis for the presenting complaints was excluded and chest radiograph, serum biochemistry, blood cell count, and thyroid function test results were normal. The male to female ratio was 12:11. Presenting complaints were dyspnea (61%), paresthesia (35%), chest pain or tightness (43%), muscle spasm (9%), dizziness (13%), palpitations (13%), and panic (30%). Similar previous episodes were reported in 74%. Misattribution of the presenting complaints to a cardiac or other life-threatening disorder was reported in 20 patients (87%) and was the main reason for their presentation to the hospital. Although no patients presented with clinical features of asthma, 7 (30%) were known asthmatics receiving treatment and another 10 (44%) had a history and investigation results suggestive of asthma. Only 2 had a history of anxiety or depression, but 17 (78%) patients exceeded the threshold for anxiety or panic on Clinical Interview Schedule (CIS-R) interview (score > or = 12). Marihuana or alcohol abuse were involved in 17% with a history of past abuse in 26%. When assessed 2 months after the attack, 13 (57%) had resting or stressor-induced hyperventilation with a significant (p < 0.05) association with asthma but not with a positive CIS-R score. These results illustrate the multifactorial basis of acute hyperventilation, the importance of misattribution, and the danger of using the term "hyperventilation syndrome" in the emergency department.

Acute Disease↗

PubMed1994

An introduction to capnography.

The aim of this article is to present an overview of the practical aspects of capnography and to define its uses and limitations. Modern rapid-response infrared CO2 analyzers are able to follow changes in CO2 concentrations within a single breath and have, therefore, gained wide clinical acceptance for respiratory monitoring and for studying aspects of respiratory control. Their use for the estimation of mean arterial CO2 tensions is limited, however, to individuals with normal lungs during resting metabolic states. They also require careful calibration taking barometric and water vapor pressure into account. Commonly encountered technical problems in capnography are condensation of water vapor and mucus plugging in the sampling tubes as well as poor recordings as a result of faulty connections and electrical interference. These can be minimized through selection and careful setting up of the most appropriate equipment for prevailing conditions. Despite some marked limitations, capnography can be a valuable tool in the assessment of ventilatory state and some aspects of respiratory control.

Carbon Dioxide↗

PubMed1994

Hyperventilation and chronic fatigue syndrome.

We studied the link between chronic fatigue syndrome (CFS) and hyperventilation in 31 consecutive attenders at a chronic fatigue clinic (19 females, 12 males) who fulfilled criteria for CFS based on both Oxford and Joint CDC/NIH criteria. All experienced profound fatigue and fatigability associated with minimal exertion, in 66% developing after an infective episode. Alternative causes of fatigue were excluded. Hyperventilation was studied during a 43-min protocol in which end-tidal PCO2 (PETCO2) was measured non-invasively by capnograph or mass spectrometer via a fine catheter taped in a nostril at rest, during and after exercise (10-50 W) and for 10 min during recovery from voluntary overbreathing to approximately 2.7 kPa (20 mmHg). PETCO2 < 4 kPa (30 mmHg) at rest, during or after exercise, or at 5 min after the end of voluntary overbreathing, suggested either hyperventilation or a tendency to hyperventilate. Most patients were able voluntarily to overbreathe, but not all were able to exercise. Twenty-two patients (71%) had no evidence of hyperventilation during any aspect of the test. Only four patients had unequivocal hyperventilation, in one associated with asthma and in three with panic. Only one patient with severe functional disability and agoraphobia had hyperventilation with no other obvious cause. A further five patients had borderline hyperventilation, in which PETCO2 was < 4 kPa (30 mmHg) for no more than 2 min, when we would have expected it to be normal. There was no association between level of functional impairment and degree of hyperventilation. There is only a weak association between hyperventilation and chronic fatigue syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Relation of hypocapnic symptoms to rate of fall of end-tidal PCO2 in normal subjects.

Hyperventilation is of little clinical relevance unless it causes symptoms. These are often non-specific. Their threshold for onset and relation to steady level of arterial (or its equivalent, end-tidal PCO2; PETCO2) are uncertain, and it has been suggested that they may relate better to the rate of fall of PCO2 than to the absolute level. We investigated this in nine normal subjects, who breathed to and fro through a pneumotachograph into an open circuit in which the concentration of CO2 could be varied. Tidal volume, respiratory frequency and ventilation was measured on-line by a Compaq computer, and PETCO2 at the mouth was measured by capnograph. Subjects overbreathed at a fixed rate and depth until symptoms consisting of dizziness, paraesthesiae and light headedness occurred. Then, without their knowledge and while they continued to overbreathe, inspired CO2 was increased to restore PETCO2 to normal and abolish symptoms, and was then withdrawn again over either approximately 0.1, 2.5 or 5 min until symptoms were again reported. The PETCO2 at this point was noted. The three protocols were performed in each subject in a random order and the same symptoms were reported each time. When averaged across all subjects, symptoms occurred at mean PETCO2 values of 20.3, 19.2 and 18.6 mmHg (2.71, 2.56 and 2.48 kPa), respectively. These were not significantly different, and it can be concluded that there was no influence of rate of fall of PCO2 on threshold for symptoms. Chest pain only occurred in one subject and may have a different mechanism.

Adult↗