PULMONARY GAS EXCHANGE DURING DELIBERATE HYPOTENSION

Respiratory physiological deadspace may increase from 35 percent of the tidal volume in the normal anaesthetized, normotensiveand supine patient to as much as 80 per cent in the hypotensivepatient in the head-up tilt. Increased mean airway pressure,hypotension, sudden head-up tilt or maintenance of tilt, alltend to increase the respiratory deadspace. Arterial and end-tidalPco² differences parallel the deadspace changes. The averagePco² difference in the supine normotensive patient was 9 mmHg, but during maintained head-up body tilt during hypotension,this difference increased to as much as 25 mm Hg. These dataemphasize the need for careful control of respiration, withhigher than normal tidal volumes and oxygen concentrations duringdeliberate hypotension. They are equally applicable to otherhypotensive states including shock     

Osteoplastic flap for obliteration of the frontal sinus: Five years’ experience

The objective of this retrospective study was to evaluate the osteoplastic flap (OPF) for the obliteration of the frontal sinus in this current era of endoscopic management of frontal sinus disease. A review of consecutive OPF procedures (n = 43) performed by the senior author (J.A.D.) from 1992 to 1997 was carried out. Data were gathered regarding chief symptom, medical history, previous sinus surgery, endoscopic findings in the office and at surgery, CT scan findings, and follow-up results (mean 19.4 months). Previous endoscopic management of frontal sinus disease had failed in 24% of patients; 97% had eventual resolution of frontal sinusitis with OPF. After OPF, 63% also had improvement or resolution of disease in other paranasal sinuses. Statistically significant, positive correlations (P < 0.05) were noted between the resolution of frontal sinusitis and improved or resolved pain, as well as the resolution of frontal sinusitis and improved or resolved infections in other paranasal sinuses. In 1998 OPF remains the standard for treating frontal sinus disease refractory to other methods. OPF can decrease the pain associated with frontal sinus infections and has a positive impact on inflammatory disease in other paranasal sinuses. (Otolaryngol Head Neck Surg 1999;121:731-5.)     

How to Implant a Leadless Pacemaker With a Tine‐Based Fixation

Two major studies have shown that leadless pacemakers are safe and effective for patients requiring right ventricular rate responsive pacing therapy. This positive result recently led to FDA approval of one of the available leadless pacing devices. While this new technology is promising, it requires a different skill set for safe implantation. In this article, we review in detail the different steps required for implantation of tine‐based leadless pacemakers while providing tips and tricks to minimize complications.     

Toll-like receptor 2 as a major gene for asthma in children of European farmers

BACKGROUND: The finding that the prevalence of asthma and allergies is less frequent in children raised on animal farms has led to the conjecture that exposure to microbial products modifies immune responses. The toll-like receptors (TLRs) represent an evolutionarily conserved family of innate immunity receptors with microbial molecules as ligands. OBJECTIVES: We reasoned that polymorphisms in genes encoding TLRs might modulate the protective effects observed in farming populations. METHODS: Farmers' and nonfarmers' children living in rural areas in Austria and Germany and who were enrolled in the cross-sectional ALEX study were genotyped for single nucleotide polymorphisms in the TLR2 and TLR4 genes. The frequencies of asthma, allergic rhinitis, and atopic sensitization were compared between the genotypes in relation to exposure to farming and endotoxin. RESULTS: Among farmers' children, those carrying a T allele in TLR2/-16934 compared with children with genotype AA were significantly less likely to have a diagnosis of asthma (3% vs 13%, P = .012), current asthma symptoms (3% vs 16%, P = .004), atopic sensitization (14% vs 27%, P = .023), and current hay fever symptoms (3% vs 14%, P = .01). The association between TLR2/-16934 and asthma among children of farmers was independent of atopy. No such association was found among children from the same rural communities but not living on farms. CONCLUSION: Our results suggest that genetic variation in TLR2 is a major determinant of the susceptibility to asthma and allergies in children of farmers.     

Liver abscess: What determines the prognosis?

Records of all patients with liver abscess who presented to a teaching hospital between 1979 and 1986 were reviewed in order to determine prognostic factors and optimal treatment. Of 32 patients, the diagnosis was made ante-mortem in 30, and 24 patients survived. Patients who died tended to be older and more likely to exhibit confusion and other features of systemic toxicity at presentation. Fine needle aspiration, guided by computerized tomography, provided the correct diagnosis in 18 of 19 patients. Of 24 patients with isolated abscesses (1 or 2) 22 survived, whereas six of eight patients with multiple (more than 2) abscesses died ( P < 0.001). Aspirates from patients who survived appeared to grow anaerobes more commonly (NS), whereas those from non-survivors more often grew multiple organisms which usually included Gram-negative bacilli ( P < 0.01). All patients received broad spectrum antibiotics and a drainage procedure was carried out in 26. Of 19 patients treated by percutaneous drainage, 12 recovered, one required hepatic resection before recovering, and six died (four with multiple abscesses). Of nine patients (all with 1–2 abscesses) treated by open drainage, all eventually recovered, but three needed additional procedures. Six of eight non-survivors compared with four of 24 survivors had predisposing biliary sepsis ( P < 0.01). It is concluded that isolated liver abscesses are relatively benign, commonly grow anaerobes, and are usually resolved with antibiotics and drainage (closed or open), whereas multiple abscesses occur in sicker, older patients who are usually jaundiced with uncontrolled biliary sepsis. The prognosis in patients with multiple liver abscesses is poor irrespective of treatment.