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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_605_Библиотеки_им_академика_М_И_Перельмана.pdf
Preconditions of Successful (Gastrointestinal) Surgery
Figure 4.11 The world’s first operation in general anesthesia in 1846: “Gentlemen,
this is no humbug.” Painting by Warren and Lucia Prosperi and displayed in “The
Ether Dome” of Massachusetts General Hospital, Boston, MA, United States.
71
Figure 4.12 (A) Schimmelbusch mask for ether anesthesia: sponges were compressed between the two grids which were sprinkled with ether. When it was positioned over nose and mouth, the patient was forced to inhale the agent (r
Deutsches Medizinhistorisches Museum Ingolstadt, Michael Kowalski); (B) a more
advanced face-modeled mask for inhalative anesthetics. From MITI.
attendance and said the famous words “Gentlemen, this is no humbug.”
Very soon, alter native anesthetic agents came into use: chloroform, N
O,
2
and others, which had to be inhalated, i.e., applied via the upper airways
during respiration.
Dedicated devices were developed and produced for the delivery of
“inhalative” anesthetics (
Fig. 4.12).
The apparatuses were continuously refined, but anesthesia remained a
side-aspect of surgery. Nonetheless, remarkable innovative approaches
were elaborated. Local anesthesia was the next step ahead.
72
Biomedical Engineering in Gastrointestinal Surgery
Figure 4.13 The three anchor points of modern anesthesia. From MITI.
By injecting and infiltrating drugs that produce a neural blockade by
interrupting impulse transmission in peripheral nerves, spinal roots, or
nerve endings, sensation is eliminated distal to the site of application.
Local anesthesia was a big step forward to make surgery safer, faster, and
less expensive. Today, local anesthesia is often combined with parenteral
drugs for sedation and analgesia
[4].
With the advent of World War II, the task of providing anesthesia was
taken over by a new medical subspecialty: anesthesia. Anesthetists became
the experts to deliver optimal conditions for the surgeons to carry
through the intervention.
In addition to inhalational anesthesia, intravenous anesthetics completed the options to guarantee the three main goals. Relief of pain or
prevention of pain, muscle relaxation, and unconsciousness were no longer effected by one single agent but divided (
Fig. 4.13). Relaxation, how-
ever, required active ventilation support.
Relaxation is the complete paralysis of all skeletal muscles of the body.
Normal tonic contraction is completely eliminated in order to prevent
movements of the patient during the operation and to facilitate surgery
(e.g., by a better exposure or additional space during laparoscopy).
However, this also means that the patient is completely unable to breath.
Controlled artificial ventilation is mandatory. For this purpose, an endotracheal tube has to be passed through the mouth or the nose and the
vocal apparatus into the upper airways (trachea) (
Fig. 4.14). As soon as
the tip of the tube is in its correct position, a balloon cuff is inflated to
Preconditions of Successful (Gastrointestinal) Surgery
Figure 4.14 (A) Endotracheal tube; (B) intubation: the endotracheal tube is inserted
into the trachea using a laryngoscope. All from MITI.
73
secure it in place and to seal the trachea to prevent gas leakage. In addition, aspiration of saliva or gastric juice is prevented.
Once it is correctly positioned and secured, it is connected to the
mechanical ventilator. The mechanical ventilator is a part of the
anesthetic machine.
These are highly sophisticated technical systems including numerous
specialized components. In addition to the ventilator, the vaporizer is
integrated for volatile anesthetics enabling exact dosage control. The
machine is connected to piped hospital gases like oxygen, nitrous oxide,
and CO
, but reserve gas cylinders are additionally provided. The third
2
element is a comprehensive monitoring system both for the ventilation
procedure as well as vital parameters.
Waste gas is not blown into the atmosphere but eliminated by a waste
gas scavenging system.
The most commonly used intraoperative ventilation modes are
volume-controlled, pressure-controlled, dual-controlled, and assisted
ventilation
[5].
Modern anesthesia carts allow anesthetists easy access to all anesthesia
tools in one movable location (
Fig. 4.15). Today, comprehensive monitor-
ing is also provided. They integrate many functions that were once exclusive to intensive care units (
Fig. 4.16).
Today, the tasks of anesthetists are not confined to the OR any longer.
They have to monitor the patient as well in the postoperative course until
the patient is sufficiently recovered to be brought back to the ward.
Intensive care units are mostly led by anesthetists. In conclusion, the range
of highly specialized anesthesia biomedical technology is too broad to be
described within the frame of this overview.
74
Biomedical Engineering in Gastrointestinal Surgery
Figure 4.15 Current state-of-the-art anesthesia unit: an anesthetic machine delivering artificial ventilation and integrated monitoring of a broad range of vital parameters. From MITI.
Figure 4.16 (A, B) Anesthesia workplace with vaporizer (A), vital signs monitoring,
ventilation control, and touchscreen for medication and event reporting (B). All from
MITI.
4.2.1 Sedation
Sedation is a method different from general or local anesthesia which is
aimed at calming the patient temporarily by means of a sedative i.v. drug.
Thus, he/she tolerates unpleasant diagnostic or therapeutic interventions
more easily. Conscious sedation is commonly used in diagnostic and therapeutic flexible endoscopy. The most popular agent today is Propofol.
Preconditions of Successful (Gastrointestinal) Surgery
75
Sedation is ideally suited for outpatients, but aftercare in a recovery room
is mandatory. The patient can be discharged with stable cardiorespiratory
parameters and as soon as previous brain function has returned.
In most countries, administration of a sedative drug (8 sedation) is
not the exclusive domain of the anesthetist but can also be done by, e.g.,
a gastroenterologist or a surgeon
[6].
4.3 DEDICATED WORKPLACE: THE OPERATING ROOM
4.3.1 The Surgical Workplace
Originally, the places in a hospital where operations were performed were
common rooms without special features. The patient laid on a simple
table without any additional functionality (
operating theaters came into use. They resembled lecture halls with
the operating table in the center. Students and visitors could attend the
interventions celebrated by the surgeon in chief (
At the end of the 19th century, the first modern designs of operating
rooms were implemented, which regarded the aspects of antisepsis, ergonomy, and the growing requirements of technical support. A trend
toward specialized workplaces could be recognized. Supply of water and
electrical current became mandatory (
Easy-to-clean surfaces (tiles, glass, etc.), metal chairs and tables were
preferred. As soon as electrical power became available, the illumination
of the surgical site could be significantly improved. Gradually, the
Fig. 4.17A). Later on, so-called
Fig. 4.17B).
Fig. 4.18).
Figure 4.17 (A) Typical chamber of a hospital where surgeries could be performed.
(B) Advanced scenario of an “operating theater” at the beginning of scientific
surgery. From reprints from our library.
76
Biomedical Engineering in Gastrointestinal Surgery
Figure 4.18 A dedicated workplace for ear, nose, and throat surgery around 1900.
From a contemporary catalog.
operating room attained its position of being the most expensive, most
dangerous, and most productive segment of the hospital.
The OR of today is a complex technical environment designed to
offer any support to the surgeon to fulfill his task.
It should be designed to be as effective as possible to achieve a high
throughput of cases in regular business hours, since maximal capacity utilization is essential in this most expensive facility of the hospital. Besides
an optimized process organization, the architecture and the design of the
surgical suite has a strong influence upon workflow efficiency. Formerly,
all pre- and postoperative activities took place in the operating theater.
Today, it is clear that a special distribution helps to optimize efficiency
since the functions of key personnel from the nursing, anesthesia, and
OR teams can be better synchronized.
The patient makes his/her w a y from the entrance , where he/she switches
from the bed/stretcher onto the OR table, to the induction room. This is the
realm of the anesthetists. The patient is prepared for the surgery, including i.v.
lines, intubation, etc. Then, he/she is brought into the OR, where surgery is
performed. After the operation, the patient is brought to the recovery r oom
until he/she is fit enough to go back to the surgical floor. The workflow is
smoothened if all units are located closely together (
Fig. 4.19).
A similar workflow is described in an instructive paper of the “OR of
the Future” of Massachusetts General Hospital, Boston, MA, United
States
[7] (Fig. 4.20).
Preconditions of Successful (Gastrointestinal) Surgery
77
Figure 4.19 OR architecture: ground plan and patient flow: (1) OR entrance; (2) induction room; (3) operating room; (4) early recovery room; (5) exit. From MITI.
4.3.2 Core Elements of the Surgical Site
Even the most different, highly specialized OR rooms have at least three
core elements in common:
• OR table,
• surgical lights,
• anesthesia equipment.
78
Biomedical Engineering in Gastrointestinal Surgery
Figure 4.20 Ground plan and patient and equipment flow of the “OR of the Future”
of Massachusetts General Hospital. The numbers in the central schematic drawing
are illustrated by the surrounding images: (1) Entrance. From Stahl JE, Sandberg WS,
Daily B, Wiklund R, Egan MT, Goldman JM, et al. Reorganizing patient care and workflow in the operating room: a cost-effectiveness study. Surgery 2006;139:71728.
Preconditions of Successful (Gastrointestinal) Surgery
Figure 4.21 (A, B) Specially designed OR tables of the beginning of the 20th century.
From a contemporary catalog.
79
Anesthesia equipment was already described in Section 4.2: Anesthesia.
OR tables are the tables on which the patient is positioned dur ing the
surgery. They have a central role, since they must guarantee an optimal
approach to the individual anatomical site, prevent positioning-induced
complications, and offer as much ergonomy to the surgical team as possible. More than 120 years ago, increasingly multifunctional, purpose-built
tables were produced (
Fig. 4.21).
Modern operating tables have to meet numerous requirements.
The height has to be adjustable, even during the interventional
procedure. Furthermore, the table top must offer the possibility of tilting
to provide optimal access to more lateral anatomical sites. Trendelenburg
and Antitrendelenburg positioning has to be possible as well as special
positioning of the extremities (arms, legs). In most cases, the table top
consists of several segments which are adjustable according to the patient’s
anatomy and the type of operation. A further property of modern
table systems is that the table top can be shifted on the column (
Fig. 4.22).
To enable intraoperative X-ray examination, it has to be made of
radiolucent materials. Last but not least, an adequate padding by special
mattresses of the table top is mandatory to avoid pressure lesions (decubital ulcers) (see Chapter 3: Principles of Gastrointestinal Surgery).
Nowadays, two types of operating tables exist: stationary systems and
mobile units. Both of these consist of three modules: the table top, the column, and the transporter. The way they are combined, however, varies.
4.3.3 Stationary Systems
They are more commonly used in Europe, and, in particular Germany
(
Fig. 4.23A). The table column is firmly anchored to the floor, and the
80
Biomedical Engineering in Gastrointestinal Surgery
Figure 4.22 Measures and functionality of a modern OR table system. Adjustments
in height, tilting in both directions and of the individual segments. Courtesy: B. Kulik,
Maquet, Rastatt, Germany.