Laparoscopy. Gasless vs. CO2 pneumoperitoneum.

OBJECTIVE: To compare gasless laparoscopy with conventional laparoscopy using CO2 pneumoperitoneum. STUDY DESIGN: Women undergoing bilateral laparoscopic tubal coagulation (LTC) were randomly assigned to one of two laparoscopy procedures: (1) a gasless laparoscopy system consisting of an intraabdominal fan retractor and electrically powered mechanical arm, and (2) standard CO2 pneumoperitoneum laparoscopy. The two laparoscopic procedures were compared on the basis of intraoperative visualization, operation duration, procedural difficulty, ventilatory parameters, hemodynamic stability, and postoperative pain and nausea. RESULTS: Significant disadvantages for the surgeon (increased technical difficulty, poorer visualization, longer operative times) and patient (greater postoperative pain and nausea) were seen with the gasless system. Because of these findings, the study was prematurely terminated after only 18 patients had participated. Intraoperative ventilatory and hemodynamic parameters were more stable in the gasless laparoscopy groups; however, the differences were not clinically significant in this population of healthy patients. CONCLUSION: The markedly increased technical difficulty and absence of clear clinical benefits for the healthy patient led to the conclusion that laparoscopy with CO2 pneumoperitoneum is preferable for routine LTC and most laparoscopic procedures in the pelvis. Gasless laparoscopy may be of benefit for the fragile patient with a compromised cardiovascular system who may suffer complications from hypercarbenemia.

Dissociation of the Jak kinase pathway from G-CSF receptor signaling in neutrophils.

Activation of the granulocyte colony-stimulating factor receptor (G-CSFR) induces rapid tyrosine phosphorylation of multiple intracellular substrates in proliferating cells and nonproliferating, terminally differentiated neutrophils. The kinases that couple ligand binding to tyrosine phosphorylation of cellular substrates by the G-CSFR with activation of specific functional programs are largely unknown. In this study, we examined early signaling events in proliferating and terminally differentiated cells following G-CSF stimulation to determine whether identical signaling cascades are activated. In murine Ba/F3 cells transfected with the human G-CSFR and NFS-60 cells constitutively expressing the murine G-CSFR, G-CSF induced tyrosine phosphorylation and activation of Jak1, Jak2, and Tyk2. Tyrosine phosphorylation of Stat3 and, to a lesser extent, Stat1 was also detected following G-CSF stimulation. Using a mitogenically incompetent human G-CSFR mutant in which Pro639 and Pro641 were substituted by alanine, the box 1 PDP motif was found to be required for activation of Jak kinases, tyrosine phosphorylation of the G-CSFR, and recruitment of Stat proteins. Notably, no activation of Jak1, Jak2, Tyk2, Stat1, or Stat3 was observed in neutrophils following G-CSF stimulation. In addition, there was no detectable activation in neutrophils of the recently cloned Jak3 kinase, which has been reported to be expressed at high levels as myeloid cells undergo terminal neutrophilic maturation. These results indicate a lack of involvement of Jak kinases in signaling by the G-CSFR in neutrophils, and suggest utilization of alternative signal transduction pathways distinct from those in proliferating cells. Activation of the Jak-Stat pathway correlates with proliferative signaling by the G-CSFR and requires the membrane-proximal box 1 PXP motif, which is conserved in members of the cytokine receptor superfamily.

Impaired ventilatory capacity after recovery from Guillain-Barré syndrome.

A 48-year-old woman who failed to disclose significant past medical history presented for laparoscopic-assisted vaginal hysterectomy with general anesthesia. After the uneventful induction of anesthesia, her trachea could not be intubated due to an extremely anterior larynx, and she was allowed to awaken. However, she developed upper airway obstruction and displayed marked muscle weakness with inadequate tidal volumes and marginal oxygen saturation. A history of prior Guillain-Barré syndrome was disclosed by the attending gynecologist. The patient's recovery was complicated by the development of postobstructive pulmonary edema and by respiratory insufficiency requiring the use of mask continuous positive airway pressure (CPAP). Despite vigorous diuresis, her respiratory status and muscle weakness did not significantly improve until she received a trial of aminophylline by infusion, after which she was able to be weaned from mask CPAP support. The patient was discharged home and returned 8 weeks later for surgery. She underwent awake fiberoptic intubation, after which general anesthesia was induced and maintained without complication. An aminophylline infusion was used in the perioperative period until the patient was successfully awakened and her trachea extubated. The frequency of residual muscle weakness after apparent full recovery from Guillain-Barré syndrome is discussed, along with the rationale for the use of aminophylline in this patient's clinical management.

A comparison of morphine, meperidine, and oxymorphone as utilized in patient-controlled analgesia following cesarean delivery.

Seventy-five patients (n = 75) undergoing elective cesarean delivery during epidural anesthesia were randomly assigned to receive one of three opioid analgesics via patient-controlled analgesia (PCA) when they first complained of pain in the recovery room. Following administration of an analgesic loading dose, patients were allowed to self-administer morphine 1.8 mg, meperidine 18 mg, or oxymorphone 0.3 mg iv every 8 min as required. Data collected during the 24-h observation period included visual analog scale (VAS) pain scores at rest and during movement, VAS patient satisfaction scores, total drug administered, the ratio of attempts/injections, and the incidence of nausea/vomiting, sedation, and pruritus. After adjusting for narcotic potency, no differences in 24-h dose requirements were noted between treatment groups (NS). All patients achieved an excellent level of analgesia at rest (NS); however, onset was most rapid with oxymorphone (P less than 0.05). The percentage of patients reporting severe pain during movement was highest in the meperidine group (P less than 0.05). Oxymorphone was associated with the highest incidence of nausea and vomiting (P less than 0.05), whereas increased sedation and pruritus were noted with morphine. Patient satisfaction with drug effect demonstrated significant negative correlations with resting pain scores and degree of sedation. Whereas morphine is a more commonly utilized PCA analgesic, the excellent analgesia, low incidence of sedation, and high patient satisfaction provided by meperidine and oxymorphone suggested useful alternatives.